Browse Topic: Transmission control units

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“Rds_on” Based OBD for Pre-Supply Fuel Pump Driver ModulesSAE-PP-001601/26/2021
In automotive electronics on-board diagnostics does the fault diagnosis and reporting. It provides the level of robustness required for the control electronics against various faults. The amount of diagnostic information available via on board diagnostics are depends on the type of vehicle. Pre-supply fuel pump is the component in the common rail hydraulic system. It pumps the fuel from the fuel tank to the inlet valve of the high pressure fuel pump. Electronic control unit synchronizes its operation with high pressure fuel pump. A dedicated driver module in the ECU controls the operation of pre-supply fuel pump. The driver module consist of an ASIC with internal voltage, current monitoring modules for the fault diagnosis and the pre-drivers to control external HS and LS power stages. The software part of the OBD programmed in the internal memory of the ASIC. The “Rds_on” of the power MOSFETs are used for the fault detection purpose. The module designed to operate in dual frequencies and variable duty cycles. It ensures the optimum hydraulic performance of the pump and provides maximum possible diagnostic coverage against various faults. The on-board diagnosis against the faults such as motor inrush current, rotor Lock, short circuit to ground, short circuit to battery, line to line fault (short circuit between high side and low side pins) and open load are discussed in this paper. The wiring harness impedance has significant influence on the fault detection duration. The wiring harness length depends on the position of ECU and pump in the vehicle. Pre-supply fuel pump normally immersed in the fuel tank and ECU normally kept either in the dash board or mounted on the body of engine. The resistance and inductance of the wiring harness are the functions of wire diameter and length. The below are the parameters influences the fault diagnostics of the driver module discussed in this paper. • Fault detection threshold (Vth), • The “Rds_on” of the MOSFET, • Fault current magnitude, • Frequency at which power stage operates, • Duty cycle, • Thermal response of the MOSFET, • Safe operating conditions, • Blind bands and MOSFET turn on/off delays. These parameters possesses typical relationships each another depending on the operating modes of engine and ambient conditions.
MobrxivNonAdmin, Lindsay
Benchmarking a 2018 Toyota Camry UB80E Eight-Speed Automatic Transmission2020-01-12864/14/2020
As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry front wheel drive eight-speed automatic transmission was benchmarked. The benchmarking data were used as inputs to EPA’s Advanced Light-duty Powertrain and Hybrid Analysis (ALPHA) vehicle simulation model to estimate GHG emissions from light-duty vehicles. ALPHA requires both detailed engine fuel consumption maps and transmission torque loss maps. EPA’s National Vehicle and Fuels Emissions Laboratory has developed a streamlined, cost-effective in-house method of transmission testing, capable of gathering a dataset sufficient to characterize transmissions within ALPHA. This testing methodology targets the range of transmission operation observed during vehicle testing over EPA’s city and highway drive cycles. With this method, the transmission is tested as a complete system, as opposed to disassembling the transmission components and testing each separately. This paper describes the benchmarking process used to gather transmission data and the test results obtained. A UB80E eight-speed automatic transmission from a 2018 Toyota Camry was installed in an engine dynamometer test cell along with a 4-cylinder 2.5L A25A-FKS engine from the same vehicle. The test dataset collected from the transmission includes gear efficiencies, torque converter slippage and K factors, spin losses, oil temperature and pressure, and CAN bus data. The transmission data collected with this benchmarking method were used as inputs to the ALPHA full vehicle simulation model. ALPHA simulation results were validated using vehicle chassis dynamometer test data from the 2018 Toyota Camry containing this engine and transmission. The ALPHA simulation also allowed the Toyota UB80E transmission to be compared to other benchmarked transmissions.
Moskalik, Andrew, Stuhldreher, Mark, Kargul, John
Objectified Evaluation and Classification of Passenger Vehicles Longitudinal Drivability Capabilities in Automated Load Change Drive Maneuvers at Engine-in-the-Loop Test Benches2020-01-02454/14/2020
The growing number of passenger car variants and derivatives in all global markets, their high degree of software differentiability caused by regionally different legislative regulations, as well as pronounced market-specific customer expectations require a continuous optimization of the entire vehicle development process. In addition, ever stricter emission standards lead to a considerable increase in powertrain hardware and control complexity. Also, efforts to achieve market and brand specific multistep adjustable drivability characteristics as unique selling proposition, rapidly extend the scope for calibration and testing tasks during the development of powertrain control units. The resulting extent of interdependencies between the drivability calibration and other development and calibration tasks requires frontloading of development tasks. Usually, drivability calibration takes place towards the end of the vehicle development program as soon as a sufficient level of product maturity is achieved. Hence, for streamlining the entire development process, various powertrain engineering tasks need to be shifted from the overall vehicle level to component conception phases. In this context, highly dynamic and appropriated “Hardware-in-the-Loop” (HiL) component test benches are the means of choice. Particularly for drivability calibration tasks, an objectified evaluation and classification approach is indispensable to be applied at HiL test benches for the identification and evaluation of drivability influencing factors during those heterogeneous testing scenarios. Before this backdrop, this article presents the transfer and validation of an objectification and classification approach for longitudinal vehicle drivability capabilities from vehicle level to highly dynamic “Engine-in-the-Loop” (EiL) test benches. First, for two different “engine control unit” (ECU) drivability calibration data sets (sporty and comfort), a multitude of automated longitudinal drive maneuvers is performed in various gears and for different start conditions with a real vehicle on a proving ground. Subsequently, these test procedures are reproduced with the same combustion engine and ECU version at an EiL test bench. Thereto, modifications and enhancements to the test bench hardware, automation system and the real-time control models are required. Their influence on the objectified drivability test results and the degree of congruence between the drivability measurements with the real vehicle on the road and the EiL test bench are determined. In this context, internal combustion engine (ICE) related measurement data are presented for individual load change drive maneuvers. By utilizing a drivability objectification approach, the differences between the two ECU drivability calibrations are determined for both test scenarios. Furthermore, various characteristic drivability attributes are illustrated and explained for several gears for both test scenarios and also directly compared to each other. In addition, the gear specific identification and reflecting quality for the different characteristic drivability attributes for both ECU calibrations are illustrated and discussed in detail by utilizing characteristic 3D diagrams. The transferability of the drivability evaluation approach from the real vehicle to the EiL test bench is validated successfully. A good correlation in the characteristic drivability attributes can be achieved between both test scenarios.
Guse, Daniel, Heusch, Christian, Klein, Serge, Fahrbach, Timm, Andert, Jakob, Pischinger, Stefan, Tegelkamp, Stefan, Nijs, Martin, Scharf, Johannes
Two-Speed Transmission Gear Shift Process Analysis and Optimization Using Genetic Algorithm08-09-01-00011/16/2020
Electric Vehicle (EV) equipped with two-speed transmission has benefit in improving dynamic performance and saving battery consumption. However, during gear shift process, torque interruption and shift impact may lead to a bad shift quality. This work investigates gear shift process in an Automated Manual Transmission (AMT) configuration-based two-speed transmission. First of all, a typical gear shift process is analyzed. Parameters like motor speed, shift force, motor torque change rate, and speed difference between synchronizer and target engage gear are all included to find the relationships with shift duration. Then vehicle jerk is introduced as a criterion to evaluate shift impact. Besides, a comprehensive shift control strategy is developed. While keeping the output torque at wheels unchanged, the shift strategy also improved motor working efficiency after gear shift. Therefore, to determine an optimum shift strategy and achieve a balance among different parameters, Genetic Algorithm (GA) multi-objective optimization method is implemented. Through GA optimization, several solutions are presented and discussed. The final results can well satisfy the requirements of different objectives. This work provides a novel and efficient method for shift strategy development.
Cao, Zhan, Yang, Jiansen, Wang, Xinyu
Harness Model Development by co-simulation of the Transmission Black Box model and Vehicle model for a Medium Heavy Duty Internal Combustion based Powertrain2019-01-226812/19/2019
With the automotive industry moving toward model based development approach, detailed model integration plays an important role in the process. In comparison to map-based models, detailed models have higher fidelity with the results being more accurate & repeatable. High fidelity models are significant as it allows for early design validation through experimentation. The primary objective of this study is to develop a co-simulation between the transmission black box in Simulink and the vehicle model in GT-Suite. The secondary objective of this study is to understand the difference in the fidelity of the map based transmission model and the detailed transmission model. For the detailed transmission model, the transmission black box provided by the supplier, is a comprehensive model setup in the Simulink platform. The co-simulation is initialized from Simulink, where in Simulink acts as the primary platform. The commands are then forwarded to GT-Suite which is embedded in the Simulink environment as an S-function. The co-simulated model has been validated against the data from the field testing. On comparison with the map based transmission model, the detailed transmission model performs much better and is able to closely emulate the real world test results. Applications of this study include fuel economy estimation, performance analysis, component sizing and optimization for current and future powertrain configurations.
Shetty, Aishwarya, Pasupathi, Santhosh, Vernham, Bruce, Bergsieker, Gerald
Hybrid Transmission for Optimizing Input Machine Operation08-08-02-000811/14/2019
The hybrid transmission with a single energy source is presented in this article, which has the ability to, under certain constraints, transfer the energy from the input shaft with arbitrary variable speed onto the output shaft with the variable speed required for an output machine or propelling member operation - without a control system. The transmission is in a way similar to a power-split transmission for hybrid electric vehicles sans the battery and a power-split control logic. Development of a dedicated control system enables the optimal operation of the input machine. As an example, the transmission is designed for a passenger automobile. For the chosen automobile type, the power train is modeled in MATLAB/Simulink. In drive simulations during the single New European Driving Cycle (NEDC), the powertrain efficiency and fuel consumption are obtained and compared with two comparable vehicles: the conventional one and the advanced HEV. The competitiveness of the proposed transmission is proven.
Jelaska, Damir, Perkušić, Milan, Podrug, Srdjan, Tvrdić , Vjekoslav
Dual Clutch Transmission Vibrations during Gear Shift: A Simulation-Based Approach for Clunking Noise Assessment2019-01-15536/5/2019
A novel methodology, for the assessment of Dual Clutch Transmission vibrations during gear shifts, is proposed in this paper. It is based on the capability to predict through numerical simulation a typical dynamic quantity used to objectively evaluate the vibrational behavior of a gearbox during experimental tests, i.e. the acceleration of a point on the external surface of the gearbox housing. To achieve this result, a two-step approach is proposed: an accurate simulation of the internal transmission dynamics and an offline uncoupled computation of the gearbox housing acceleration from the output of the simulation. The first step required the definition of a suitable nonlinear lumped parameter model of the car equipped with a DCT that was implemented in Amesim software. The second step, developed as a post processing tool in Matlab, is based on the knowledge of the inertance Frequency Response Functions (FRFs) between a single component of force applied in a bearing and a single component of acceleration in the measurement point. The indices used to assess the clunk severity are peak to peak amplitude and RMS of the gearbox housing acceleration. The effectiveness of this method is proven by comparing experimental and simulated trends of the clunk indices.
Galvagno, Enrico, Dimauro, Luca, Mari, Gianluca, Velardocchia, Mauro, Vella, Angelo Domenico
Integrated Multi-Physics Simulation for Full-Vehicle Low Frequency NVH Optimization in HEVs2019-01-14556/5/2019
The recent automotive industry trend towards electrification has created new challenges for NVH engineers. These challenges stem from new powertrain architectures and their complex interactions, the governing control strategies which aim to optimize energy management, and new unmasked sources of excitation. Additionally, vehicle manufacturers are attempting to reduce hardware testing in order to rapidly satisfy increasing production demand and to minimize its costs. Hence, to meet the above-mentioned challenges up front in the development process of Hybrid Electrical Vehicles (HEVs) while balancing competing design objectives of drivability, durability and NVH, a simulation-led design and optimization is required. NVH problems are often the result of mechanisms that originate through complex interactions between different physical domains (flow, electromagnetic, structural/mechanical, control logic, etc.) and the assembly of individual components into a complete system. Therefore, accurate system-level integrated models are becoming a requirement to solve modern NVH problems. Combining the optimal balance between simulation and experimental data, this article describes a joint effort between Ford and Gamma Technologies to develop a general methodology to perform full-vehicle low frequency NVH analysis. Using GT-SUITE software, a non-linear multi-physics simulation model of a rear wheel drive HEV was created. The model was exercised to accurately evaluate the effects of powertrain control strategy and component selection on low-frequency NVH performance during a tip-in regeneration, downshifting and in-gear acceleration maneuvers while minimizing the computational cost.
Gomez, Llorenc Foraste, Zeman, Jonathan, Liu, Jack
Development of Electric Oil Pump Controller in Hybrid Vehicle Based on PMSM (Permanent Magnet Synchronous Motor) and the AUTOSAR Platform2019-01-07654/2/2019
Traditional hybrid vehicles operated two types of oil pump, mechanical for combustion engine and electrical for electric motor, to supply oil pressure for automatic transmission in each power source. New hybrid vehicles has only one electrical pump to reduce system volume and to improve fuel efficiency. Purposes of this study are to make standardization of firmware development process for oil pump unit (OPU) and electric oil pump (EOP) and to apply permanent magnet synchronous motor (PMSM) instead of brushless DC (BLDC) motor. In old-fashioned non-operating system (OS) firmware, it was convenient to calculate control timing for motor control, however the firmware was deeply dependent to specific microcontroller Unit (MCU). In other words, much of efforts and time are needed if new MCU were applied. In this study, new standard development process for MCU firmware can be built up based on automotive open system architecture (AUTOSAR) platform by developing specific motor complex device driver (CDD). In existing system, the OPU supplied with high-voltage from battery drives the BLDC motor driven with six-step block commutation method through the hall sensor inputs. In new system of this study, sensorless vector control algorithm for PMSM is applied to improve motor performance and sensorless algorithm helps to reduce failure risk caused by position sensor.
Kim, Haejin, Ryu, Seung-yun, Yoo, Hojeong, Kim, Hyoungsu, Kim, Gyeongcheol
Sensor Selection for Selective Clutch Fault Isolation in Automatic Transmissions Based on Degree of Fault Tolerance2019-01-01174/2/2019
Multiple clutches are engaged to achieve a specific gear ratio in an automatic transmission (AT). When an engaged clutch loses pressure during the AT operation, it is classified as a clutch stuck off fault. Automatic transmissions can enter in neutral states because of these faults and the vehicle can lose power at the wheels. Our previous work describes a systematic way of performing sensor placement analysis for diagnosis of clutch faults in automatic transmissions. In this paper, we approach the issue from the point of view similar to that of functional safety according to the ISO 26262 standard; where a transmission functional safety concept should address transitioning to a safe state in case of hazards associated with stuck off clutches. We try to address the questions whether all the faults really need to be isolated from each other and whether it is possible to isolate only a subset of faults to reduce the number of required sensors and still maintain a reasonable performance/safety. A way to classify clutch faults based on fault tolerant actions and the degree of fault tolerance is described. A structural analysis-based approach is then used to answer the question of sensor placement for selective fault isolation. The proposed approach is applied to a 10-Speed automatic transmission as an example. The paper concludes by demonstrating the effectiveness of selective fault isolation and discusses other applications of the approach.
Deosthale, Eeshan Vijay, Ahmed, Qadeer, Rizzoni, Giorgio, Mohammed, Majed, Hathaway, Richard, Henning, Abigail A.
Design, Analysis, Simulation and Development of a Ravigneaux Gear-Train2019-26-02501/9/2019
With increased vehicular traffic density a trend has been observed where customers have started preferring automatic transmission in place of its manual version. This Automatic transmission not only shifts the gear automatically, with the help of sensors and actuators, but they are also tuned for better performance of the vehicle in terms of fuel efficiency and emission. This all comes at the cost of power consumption from the battery, increment in cost, weight and complexity. The main parts of an automatic transmission include Torque Convertor, Sensors, Actuators, Transmission Control Unit (TCU) with the epicyclic gear-train being the heart of it. In terms of use in the automotive, a system of epicyclic gear-train can provide only 2 gear ratios. Ravigneaux gear-train is the modified version of epicyclic gear-train where there are two set of Planet gears and Sun gears or Ring gears thereby capable of giving 4 gear ratios with a single system. This paper discusses the design analysis and optimization of Ravigneaux Gear-train. To compare it with Simpson gear-train, simulation of both the gear-trains are done on MATLAB(Simulink), keeping all other parameters of the vehicle like gear ratios, engine and vehicle parameters etc same and the results are compared. Acceleration for both the vehicles were same as the within 8 sec vehicle crossed the 100 kmph mark. Nature of Engine Power curve is also same for both of them. Finally, a table top model of Ravigneaux gear-train is manufactured and its performance is experimentally observed. The results are compared with percentage change in the velocity ratio and it was found that the results are within 10% of the calculated value.
Moulick, Enanko, Wani, Kiran, Kapoor, Karan, Rawat, Ankit
Investigation of the Hybrid Operating Modes Regarding Efficiency, Emissions and Comfort for the Parallel-Series Hybrid Powertrain Concept DE-REX2018-01-18289/10/2018
The “Two-Drive-Transmission with Range-Extender” (called DE-REX) is an innovative hybrid powertrain concept using two electric motors and an internal combustion engine. The two electric motors are permanent magnet synchronous motors with a maximum power of 48 kW each. As combustion engine a 3 cylinder, turbocharged engine with a power of 65 kW is used. The aggregates are coupled to a transmission whose layout is characterized by consisting of two parallel 2-speed sub-transmissions. This layout offers a high flexibility and enables both parallel and series hybrid driving. The hybrid control unit (HCU) has to select the optimal driving mode and power distribution between the aggregates in regard to in some extend competing objectives like efficiency, emissions or driving comfort. In particular, the operation of the internal combustion engine with only two gear ratios is challenging. In the course of the publically funded DE-REX project, the DE-REX powertrain concept was designed, manufactured and set up at an X-in-the-loop test rig. In this paper, the operating point decision is investigated in selected driving situations focusing at the conflict of objectives between the efficiency, the emissions of the combustion engine and the driving comfort. Therefore different hybrid control strategies are introduced on the basis of measurements at the powertrain test rig. Each strategy was designed to aim for one of the objectives gaining advantage out of the high flexibility of DE-REX. The availability of three propelling machines, gear selection and different hybrid modes opens up a wide field of driving power supply possibilities. The different strategy approaches show how an innovative powertrain design can improve system characteristics of modern hybrid vehicles.
Fischer, S., Viehmann, A., Beidl, C., Rinderknecht, S.
Structural Analysis Based Sensor Placement for Diagnosis of Clutch Faults in Automatic Transmissions2018-01-13574/3/2018
This paper describes a systematic approach to identify the best sensor combination by performing sensor placement analysis to detect and isolate clutch stuck-off faults in Automatic Transmissions (AT) based on structural analysis. When an engaged clutch in the AT loses pressure during operation, it is classified as a clutch stuck-off fault. AT can enter in neutral state because of these faults; causing loss of power at wheels. Identifying the sensors to detect and isolate these faults is important in the early stage of the AT development. A universal approach to develop a structural model of an AT is presented based on the kinematic relationships of the planetary gear set elements. Sensor placement analysis is then performed to determine the sensor locations to detect and isolate the clutch stuck-off faults using speed sensors and clutch pressure sensors. The proposed approach is then applied to a 10-Speed AT to demonstrate its effectiveness. A simulator is developed to qualitatively study the effects of clutch stuck-off faults on speeds of different elements in an AT. Simulator results are presented to support the sensor placement analysis. Later, a comparative analysis of different sensor sets based on the cost and performance is conducted to choose the optimal sensor combination. This paper concludes by discussing in detail the different sensor sets that give different fault isolation performance and suggests that only increasing number of sensors does not guarantee better fault isolation.
Deosthale, Eeshan Vijay, Ahmed, Qadeer, Arasu, Mukilan, Rizzoni, Giorgio, Mohammed, Majed, Hathaway, Richard
Design Optimization of the Transmission System for Electric Vehicles Considering the Dynamic Efficiency of the Regenerative Brake2018-01-08194/3/2018
In this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car. Quasi static system models, including the vehicle model, the motor, the battery, the transmission system, and drive cycles are established in MATLAB/Simulink at first. Specifically, since the regenerative braking capability of the motor is affected by the SoC of battery and motors torque limitation in real time, the dynamical variation of the regenerative brake efficiency is considered in this study. To obtain the optimal gear ratios, iterations are carried out through Nelder-Mead algorithm under constraints in MATLAB/Simulink. During the optimization process, the motor efficiency is observed along with the drive cycle, and the gear shift strategy is determined based on the vehicle velocity and acceleration demand. Simulation results show that the electric motor works in a relative high efficiency range during the whole drive cycle. The energy economy of the case-study vehicle with the optimized a two-speed transmission is also compared to that of the baseline vehicle with fixed-ratio reduction gear.
Zhao, Bolin, Lv, Chen, Hofman, Theo, Steinbuch, Maarten, Zhang, Junzhi, Cao, Dongpu
Travelling Resistance Estimation and Sandy Road Identification for SUVs2018-01-05784/3/2018
The mechanical properties of sandy road are quite different from those of hard surface road. For vehicle control systems such as EMS (engine management system), TCU (transmission control unit) and ABS (antilock brake system), the strategies and parameters set for solid surface road are not optimal for driving on sandy road. It is an effective way to improve the mobility of all-terrain vehicles by identifying sandy road online and shifting the control strategies and parameters of control systems to sandy sets. In this paper, a sandy road identification algorithm for SUVs is proposed. Firstly, the vehicle signals, such as engine torque and speed, gear position, wheel and vehicle speed, are acquired from EMS, TCU and ESP (electronic stability program) through CAN (controller area network) bus respectively. Based on the information and longitudinal force equilibrium equation, the travelling resistance of vehicle is estimated. The hydraulic torque converter is divided into several parts to calculate the acceleration resistance instead of using the rotational inertia coefficient. Then, the sandy road identification algorithm is proposed mainly based on the travelling resistance. Finally, real vehicle tests are carried out on different road conditions. After cone index penetrometer and soil hygrometer are used to measure the sandy test fields, performances of the travelling resistance estimation method and sandy road identification algorithm are validated. The results show that the identification algorithm designed in the paper can identify the sandy terrain effectively.
Wu, Weixiang, Zhang, Jian, Zhao, Jian, Zhu, Bing
Product Line Engineering for Basic Software of Automotive Embedded Systems2018-01-14574/3/2018
In the early 1980s, an oxygen sensor was applied to improve the fuel efficiency of automotive embedded systems. Currently, the complexity of software development has being increased due to the emergence of various requirements and the electronic control devices to ensure the safety and convenience of the driver. The high-performance hardware embedded in the ECU is a big issue for the automobile industry. OEMs, TIERs, tool providers, and the others are aiming at a variety of unit reusability, including software and hardware, based on the plug-and-play architecture concept. It is enhancing the quality attributes (safety, performance, real-time) of various perspectives. Furthermore, international standard process (ISO 26262, A-SPICE) does not provide a direct methodology for dealing with requirements refinement procedures, standard specification methods, and traceability of extracts. Although the area of the conventional basic software, which is the other area excluding the application in the entire software of the embedded system, was not subject to reuse unit in the past, the reusability of the basic software becomes important due to various backgrounds, including explosion, management of system variations. However, there is a lack of an efficient methodology for the reuse-based development process of the basic software throughout the international automotive industry. In this paper, we acquire and evaluate core assets through a feature-based product engineering approach to TCU, AWD, and SCU in HYUNDAI AUTRON Powertrain Control Systems. By introducing the application examples of new system development, we examine the effects of the basic software reusability.
Park, Joonhyun, Han, SeonMi
Electronic Horizon: A Map as a Sensor and Predictive Control2017-01-19458/25/2017
During recent years, all major North American and European commercial vehicle OEMs have introduced predictive functionalities based on an electronic horizon for their on-highway fleets. This is a system concept that lets vehicles know what is happening on the road ahead and allows them to react to that information without driver involvement. When an electronic horizon is used in heavy-duty trucks, a significant reduction in fuel consumption is possible as a key application. This is achieved by optimizing the algorithms in the engine control unit, the transmission control device or other control units in the vehicle. There is a clear business case for the vehicle owners. In this paper we review the long development from early navigation technologies to an in-vehicle sensor, called an electronic horizon. We present an overview of different architectures from several perspectives as well as multiple use cases for commercial vehicles. Furthermore, we look at the future, in which the electronic horizon will be able to save location-related vehicle data and transfer it to a cloud or deliver dynamic data for the road ahead such as traffic jams, accidents or weather conditions. Finally, we examine the relevance of the electronic horizon for important future innovations such as the connected powertrain and autonomous driving.
Varnhagen, Dr. Raimund
Development of a Cruise Controller Based on Current Road Load Information with Integrated Control of Variable Velocity Set-Point and Gear Shifting2017-01-00893/28/2017
Road topography has a remarkable impact on vehicle fuel consumption for both passenger and heavy duty vehicles. In addition, erroneous or non-optimized scheduling of both velocity set-point and gear shifting may be detrimental for fuel consumption and performance. Recent technologies have made road data, such as elevation or slope, either available or measurable on board, thus making possible the exploitation of this additional information in innovative controllers. The aim of this paper is the development of a smart, fuel-economy oriented controller adapting cruising speed and engaged gear to current road load (i.e. local slope). Unlike traditional cruise controllers, the velocity set-point is not constant, but it is set by applying a mathematical transformation of the current slope, accounting for the mission time duration as well. A smart shifting logic operation has also been implemented according to the following rules: i) avoid excessive shifting; ii) choose suitable gear to deal with road load while iii) respecting engine operation constraints and iv) keep the engine speed in its maximum efficiency range. Furthermore, in order to enhance fuel economy, the opportunity to decouple the engine from the driveline (i.e. using the neutral gear), when resistant load is below a given threshold, has been explored. The proposed controller is assessed in terms of both fuel savings and travel time through an exhaustive simulation analysis carried out for a heavy duty truck running on different test routes and for multiple payload configurations.
D'Amato, Antonio, Donatantonio, Fabrizio, Arsie, Ivan, Pianese, Cesare
Multi-Performance Optimal Gearshift Schedule of Stepped Automatic Transmissions Adaptive to Road Slope2017-01-11373/28/2017
For the vehicle equipped with stepped automatic transmission (SAT) that has a fixed number of gears, gearshift schedule is crucial to improve the comprehensive performance that takes into account power performance, fuel economy, and driver’s performance expectation together. To optimize and individualize the gearshift schedule, an optimization method and an improved performance evaluation approach for multi-performance gearshift schedule were proposed, which are effective in terms of reflecting the driver's expectation on different performance. However, the proposed optimization method does not consider the influence of the road slope on the comprehensive performance. As the road slope changes the load of vehicle that is different from the load when a vehicle runs on a level road, the optimized gearshift schedule without considering road slope is obviously not the optimal solution for a vehicle equipped with SAT when it runs on ramp. To this end, the influence of the road slope on the gearshift behavior has been analyzed at first, and then an optimization method which takes into account the slope resistance has been proposed. Based on that, a number of multi-performance gearshift schedules adaptive to different road slopes have been optimized. To evaluate the improved gearshift schedule optimization method, simulations of driving on ramp with fixed slope angle under 100% throttle opening, and simulations of driving under a modified driving cycle on ramps with both fixed and changing slope angles using different gearshift schedules, have been carried out. The simulation results show that the proposed gearshift schedule could improve the vehicle performance through eliminating gearshift cycle with slight but acceptable reduction of fuel economy when it runs on ramp.
Yin, Xiaofeng, Lu, Han, Wu, Xiaohua, Zhang, Yongtong, Luo, Wei
A Unified Creep-Speed Control Approach for Automated Parking System2017-01-06093/28/2017
This paper presents a unified creep-speed controller specifically designed for the automated parking system of an automated manual transmission vehicle, whereby the engine management system, transmission control unit, and electronic stability control system can work cooperatively and harmoniously within the same control framework. First, a novel reference speed generator is designed and employs sinusoidal functions to produce the speed profile based on the maneuver-dependent distances computed by a path planner, such that the lag in vehicle response during start-up can be effectively reduced. Second, a well-tuned PID controller is adopted to determine the resultant longitudinal force in attempt to follow the reference speed and eliminate the distance error during the parking maneuvers. Third, the electronic control units in the powertrain and brake systems interact with one another and generate exclusive control actions in order to achieve the desired motion control command, where the non-smooth actuator nonlinearities are explicitly addressed. Finally, the proposed controller is validated through simulation to improve the tracking accuracy of the predefined time-dependent parallel-parking trajectory at creep speeds.
Song, Pan, Xie, Shugang, Zhong, Yuan, Gao, Bolin
Shift-by-Wire System for Lexus RWD Vehicles2017-01-10943/28/2017
Shift selection devices are desired to be flexible for design and layout, in order to realize the next generation of cockpits for Lexus vehicles. In addition, refined shift operation feelings are also required to be suitable for Lexus vehicles. To meet these demands, the Lexus LC500 has been equipped with a shift-by-wire system, which replaces the mechanical linkage between the shift selector and transmission with electrical signals and an actuator. This shift-by-wire system will be installed in a wide variety of Lexus powertrain lineup, including conventional gas vehicles and hybrid vehicles. Therefore, the next generation shift-by-wire system for Lexus has been developed with high reliability and applicability. This technology will be essential when autonomous driving and autonomous parking systems are realized in the near future. To enable shifting of the parking mechanism in a simple configuration regardless of the engine operation state, shifting of the parking mechanism is performed by an add-on electric parking actuator, and shifting the driving force direction is performed by a transmission control unit in each powertrain system. The shift selection method basically follows an “h” pattern shift lever and a push-type parking switch, which Toyota has used in hybrid vehicles for many years. Additionally, emotional shift selection devices are even more in tune with the driver’s senses. The new flat type high-output parking actuator is developed to enable adoption of this system in rear-wheel drive (RWD) vehicles. This application has a difficult installation environment in terms of space and heat between the transmission and the floor tunnel, and also requires large torque to shift the parking mechanism because of the comparatively high vehicle weight. This paper outlines the new system and its major technologies.
Nakade, Yusuke, Kamada, Atsushi, Ueno, Koki, Kume, Mikine, Sakaguchi, Kouji
Efficient Dual Clutch Transmission Family for Transversal, Transaxle Powertrains2017-26-00361/10/2017
The reduction of CO2 emissions at vehicle level through the improvement of transmission efficiency represents the essential goal of transmission development engineers. New requirements, such as the recovery of the kinetic energy of the vehicle while coasting, the hybridization of drivetrains and autonomous driving, are challenges that can best be overcome with automatic transmissions. Dual clutch transmissions (DCT) with power-on-demand actuation systems offer a particularly efficient method of meeting the new requirements. However, many markets show vehicle applications with production volumes of less than 100.000 units per year. FEV’s new DCT family is conceived especially for customers in these markets. The re-use of proven subsystems which are already in series production results in a "business case" for applications with lower volumes also. This article introduces this transmission family.
Steinberg, Ingo, Freiholtz, Dan, Hellenbroich, Gereon
“Rds_on” Based OBD for Pre-Supply Fuel Pump Driver Modules2017-26-03481/10/2017
In automotive electronics on-board diagnostics does the fault diagnosis and reporting. It provides the level of robustness required for the control electronics against various faults. The amount of diagnostic information available via on board diagnostics are depends on the type of vehicle. Pre-supply fuel pump is the component in the common rail hydraulic system. It pumps the fuel from the fuel tank to the inlet valve of the high pressure fuel pump. Electronic control unit synchronizes its operation with high pressure fuel pump. A dedicated driver module in the ECU controls the operation of pre-supply fuel pump. The driver module consist of an ASIC with internal voltage, current monitoring modules for the fault diagnosis and the pre-drivers to control external HS and LS power stages. The software part of the OBD programmed in the internal memory of the ASIC. The “Rds_on” of the power MOSFETs are used for the fault detection purpose. The module designed to operate in dual frequencies and variable duty cycles. It ensures the optimum hydraulic performance of the pump and provides maximum possible diagnostic coverage against various faults. The on-board diagnosis against the faults such as motor inrush current, rotor Lock, short circuit to ground, short circuit to battery, line to line fault (short circuit between high side and low side pins) and open load are discussed in this paper. The wiring harness impedance has significant influence on the fault detection duration. The wiring harness length depends on the position of ECU and pump in the vehicle. Pre-supply fuel pump normally immersed in the fuel tank and ECU normally kept either in the dash board or mounted on the body of engine. The resistance and inductance of the wiring harness are the functions of wire diameter and length. The below are the parameters influences the fault diagnostics of the driver module discussed in this paper. Fault detection threshold (Vth), The “Rds_on” of the MOSFET, Fault current magnitude, Frequency at which power stage operates, Duty cycle, Thermal response of the MOSFET, Safe operating conditions, Blind bands and MOSFET turn on/off delays. These parameters possesses typical relationships each another depending on the operating modes of engine and ambient conditions.
Mathew, Renny
Signal Generator for Prediction of Transient Control Signals of an Automotive Transmission Control Unit Depending on Scalar Calibration Parameters2016-01-215510/17/2016
In this investigation an innovative signal generator will be introduced, which enables the generation of transient control signals for the gearshift process. The signals are generated merely depending on scalar transmission control unit (TCU) calibration parameters. The signal generator replaces the comprehensive TCU software within the simulation environment. Thus no extensive residual bus simulation is required. Multiple experimental models represent the core part of the signal generator. To predict the system behavior of the underlying system, the models are trained using measured data from a powertrain with automatic transmission mounted on a test rig. The results demonstrate that the introduced signal generator is suitable to predict transient control signals for the gearshift operation accurately. In combination with an additional powertrain model it is possible to simulate the gearshift process and subsequently to evaluate the gearshift comfort. The signal generator allows a rapid implementation of a simulation environment for TCU calibration with less modeling effort in comparison with the implementation of the original TCU software. Due to a flexible approach, the signal generator offers to predict signals with any course. Hence, it also allows to predict gearshift-comfort relevant signals directly without using a powertrain model. In conclusion the introduced signal generator emphasizes an universal tool with high potential for model based calibration.
Rot, Ivan, Rinderknecht, Stephan
Addressing Variation in Full Vehicle Automatic Transmission Fluid Fuel Economy Testing2016-01-220710/17/2016
With government mandates, original equipment manufacturers are increasingly focusing on fuel economy and finding efficiency gains throughout the vehicle. Lubricant companies have been asked to design fluids that aid in this effort. Demonstrating real gains becomes complex given the intricacies of these systems and methods range from bench top screen tests to component test stands to full vehicle testing. This paper addresses the variation that was encountered when testing automatic transmission fluid efficiency within a full vehicle test. While it is well known that variability in testing conditions such as engine load or vehicle speed will lead to variability in results, the magnitude of their impact on average throughout the test cycle suggests that repeat testing may not be sufficient to guard against improper conclusions. In fact, our data indicates that typical differences in average conditions across the cycle can be associated with predictable impacts in test results of 0.7%-1% for vehicle fuel economy (in miles per gallon) when tested on the Highway Fuel Economy Test (HFET). In this paper we discuss an empirical model that quantifies the impact average operating conditions observed during the HFET test cycle can have on the miles per gallon reported for that cycle. This model explains differences between laboratories as well as replications over time at the same laboratory. In many cases normalizing test results to adjust for the average operating conditions could be an economical way to improve the ability to discriminate among fluids.
Schiferl, Elizabeth, Hunt, Timothy N., Slocum, Robert
In-Tractor Cloud: A Vision of Service-Oriented System Design Enabled by High-Speed In-Vehicle Networks for a Safer Task and Machine Management2016-01-81309/27/2016
Automotive industry compartment is undertaking a massive technology revolution. ADAS systems and infotainment promise to change the way that customers mean travel and transportation radically, through several use cases. The key enabling technologies for this trend are Ethernet and its newly standardized physical layer, IEEE 802.3bw 100BASE-T1 (a.k.a. BroadR-Reach). From an architectural point of view, the evolution of the applications that rely on Automotive Ethernet resembles in many ways the evolution that the IT has had in the last decades. In the IT world, increased throughput and computational power to the end-user enabled technologies like multimedia streaming; scalability and availability requirements, together with the increased complexity of IT infrastructure, led to the “Anything as a Service” paradigm and Software Defined Networks. For what concerns commercial vehicles, new use cases and the enhancement of some existing ones, require the adoption of a high-speed network like Ethernet. The paper proposes a novel approach that enables new perspectives and applications in commercial vehicles and especially in Agricultural Machines, borrowing the best practices and the background of IT technologies and is intended to be a seminal work to delineate a new concept in the commercial, Agricultural and Heavy-Duty vehicles system design, especially for what concerns the network and services. The work will first review the established IT semantics and architectures, then the possibilities and challenges of commercial vehicles applications will be examined, pointing to real use-cases. The emerging paradigm is here called “In-Tractor Cloud”. This paradigm brings advantages like scalability, component reuse, HW/SW decoupling and better resource utilization, providing a future-proof architecture. The paper describes a promising system approach where computation, platform, redundancy, are conceived as services, and it shows how this paradigm will enable a very efficient and service oriented management of Security, Privacy, Dependability, Performance and Safety.
Malaguti, Giorgio, Ruggeri, Massimiliano, Dariz, Luca, Selvatici, Michele
Vehicle and Drive Cycle Simulation of a Vacuum Insulated Catalytic Converter2016-01-09674/5/2016
A GT-SUITE vehicle-aftertreatment model has been developed to examine the cold-start emissions reduction capabilities of a Vacuum Insulated Catalytic Converter (VICC). This converter features a thermal management system to maintain the catalyst monolith above its light-off temperature between trips so that most of a vehicle’s cold-start exhaust emissions are avoided. The VICC thermal management system uses vacuum insulation around the monoliths. To further boost its heat retention capacity, a metal phase-change material (PCM) is packaged between the monoliths and vacuum insulation. To prevent overheating of the converter during periods of long, heavy engine use, a few grams of metal hydride charged with hydrogen are attached to the hot side of the vacuum insulation. The GT-SUITE model successfully incorporated the transient heat transfer effects of the PCM using the effective heat capacity method. A variety of conventional, stop-start and hybrid electric vehicles have been simulated over standard drive cycles using this model. For each vehicle, prep-cycle simulations were followed by soak simulations of differing time periods. Model predictions show that the VICC was able to maintain converter temperatures above 300°C for at least 12 hours for all of the simulated vehicles and standard prep-cycles. Furthermore, this heat retention ability directly translated to a proportional reduction in cold-start exhaust emissions. With the introduction of intermediate soak times as part of the EPA emissions test regulations, the benefits of the VICC should be seen in all standard drive cycle emissions tests. The simulation results of the GT-SUITE model demonstrate the contribution of the Vacuum Insulated Catalytic Converter in meeting stringent future emission standards.
Daya, Rohil, Hoard, John, Chanda, Sreedhar, Singh, Maneet
Neural Network Transmission Control2016-01-00894/5/2016
This Application is using Multilayer Perceptron Algorithm to predict the shifting gear timing based on throttle percentage, vehicle velocity, time history and engine speed, in order to enhance the fuel efficiency, shifting time, power loss and driver’s comfort during shifting. The model makes no assumptions about how transmission performance aspects like gears slipping time or the existence of distinct environments like high temperature affects the power train system performance. Instead, the model can learn to model any type of distortion or additive noise in the sensor data; induced in the CAN protocol, through sufficient training data characterization. The network will be implemented on an AMESim model to characterize the operating temperatures and optimize the gearbox design to work with an optimal temperature and advance to this temperature during operation. Multilayer Perceptron Algorithm possesses important properties such as many degrees of freedom, non-linearity, and dissipations. The identification of stability attractors of the lyapunov function with associative memories and input - output mappers is one of the foundations of neural network paradigms through controlling the locations of the attractors in the state space of the system. The Algorithm role to take the form of the nonlinear dynamic equation that manipulates the locations of the attractors for the purpose of encoding information in a desired form. In this way, it is possible to establish an intimate relationship between the physics of the transmission and the algorithms computations.
Barakat, Mohamed Samy, Abdelaziz, Mohamed
GPGPU-Based High Performance Parallel Computation Method for Valve Body Failure Mode2016-01-13534/5/2016
The method that enables a Simulink model to execute parallel computation by using GPGPU technology is introduced. The GPGPU, General-purpose computing on graphics processing units, is a technology to accelerate program by using graphic card instead of CPU computation. This method was developed to reduce the time to detect failure mode of automatic transmission’s valve body. The valve body is the major part of automatic transmission. It is extremely important to confirm the functional safety of automatic transmission in the case that any parts of valve body failed. We have developed Simulink-based valve body failure mode simulator, and made a considerable contribution for this work. However, the number of failure mode is increasing recently. Therefore, we made the simulator to compute at a high-speed using GPGPU technology. We have sharply reduced the computation time and strengthened the computing ability to support the detection for an increasing amount of failure modes. In addition, we have automated almost a whole detection process and have made the simulator easier to use and scalable from now.
Suzuki, Tomonori, Mani, Tsutomu, Tsuchida, Kenichi, Yamaguchi, Masamichi
Performance Evaluation Approach Improvement for Individualized Gearshift Schedule Optimization2016-01-11474/5/2016
To improve the comprehensive performance of vehicles equipped with stepped automatic transmission (SAT), the optimization of gearshift schedule should take into account various performance such as power performance, fuel economy, etc. In addition, the SATs would become more acceptable if the optimized gearshift schedule could also be individualized to reflect the driver’s expectation on vehicle performance to a reasonable extent. For the purpose of ensuring the comprehensive performance and improving the individual-ability (i.e., the ability to adapt to different driver’s performance expectation) of vehicles equipped with SAT, a linear weighted method has been proposed to construct a performance evaluation function, which applies different weights to represent driver’s expectation on performance by using these weights to multiply the normalized value of each sub-performance index. Taking this evaluation function as the optimization objective, several gearshift schedules of a vehicle equipped with an automated manual transmission (AMT) have been optimized with genetic algorithm (GA). Although the optimized power performance dominated and fuel economy dominated gearshift schedules can reflect the driver’s intention, the change of the control parameters is not very sensitive to the change of the weights in some areas. To this end, an improved evaluation approach to make the gearshift schedule be more sensitive to the change of the weights has been proposed. In this approach, the optimal solutions for each sub-performance are calculated at first, and then the square of the difference between the normalized optimal value and the normalized actual value of each sub-performance index is used to replace the normalized value of each sub-performance index in the linear weighted method, to construct the improved evaluation function. Simulation results show that the modified evaluation function can improve the sensitivity of the change of gearshift control parameters to the change of weights, and the gearshift schedules can be individualized by assigning different value to the weights to satisfy different driving preference.
Yin, Xiaofeng, Lu, Han, Zhao, Xiaojuan, Wu, Xiaohua, Zhang, Yongtong
Comparison of Parameter-Identified Simulation Models with Different Detailing Level to Reproduce the Side Shaft Torque of an Automotive Powertrain with Automatic Transmission2016-01-11484/5/2016
The underlying basic model represents a powertrain with automatic transmission including a torque converter. It is based on a greybox-modeling approach, which refers to ordinary differential equations with identified parameters and characteristic curves. The validated basic model is extended in order to reproduce the system behavior and especially the side shaft torque during a gear shift process. Therefore the model is extended by a transmission model with clutches for gear shifting in order to simulate specific powertrain dynamics additionally. The parameters have already been determined for the basic model using a method for isolated and structured parameter identification based on measurement data of an automotive powertrain test bench. A comparable structured parameter identification method is applied to obtain the parameters of the extended model. The extended model will be compared with a state observer which is based on a low-order model and neglects the detailed consideration of submodels with nonlinear characteristics. The observer also reconstructs the side shaft torque during the entire maneuver and will be consulted as an alternative approach for estimating non-measurable states in the system. Comparing the extended model with the observer model will illustrate the limits and potentials of both approaches. The simulation results are compared and evaluated based on the measured side shaft torque. Within this study the extended powertrain model is used as reference model that describes the vehicle dynamics for the considered maneuver precisely, whereas the observer is an alternative approach trying to reach similar results mainly obtained from the measured speed signals.
Yousif, Leonard, Rot, Ivan, Rinderknecht, Stephan
A New Control Scheme for Automated Manual Transmission with Electromagnetic Powder Clutch2015-24-25479/6/2015
This study aims to provide modeling and control approaches for automated manual passenger and commercial vehicle transmissions in order to improve the overall disengagement-gear shifting-engagement performance using electromagnetic powder clutch (EMPC). The rationale behind selecting this clutch is its rapid behavior. During the modeling procedure of the EMPC, the analogy between this type of clutches and dry plate friction clutches has been exploited and a simple control method is proposed. The study also includes modeling method for gear shifting and selecting mechanisms of the automated manual transmission gearbox as well as development and implementation of controllers which is designed for these mechanisms. Automated manual transmission gearbox is utilized due to its combination of ease of construction and ability for electronic automation.
Ergenc, Ali Fuat, Ergenc, Alp, Erdogan, Caner, Dumanli, Alper
Design of an Eddy Current Torque Bypass Clutch for Seamless Automated Manual Transmissions of Electric and Hybrid Vehicles2015-01-91437/1/2015
This paper presents the design and experimental validation of an eddy current torque transfer clutch for use inside Automated Manual Transmissions (AMTs) to perform seamless gear upshifts. Electric vehicles (EVs) with a single-ratio gearbox may provide high levels of smoothness, but using a multi-speed gearbox provides significant benefits in terms of vehicle acceleration, top speed, powertrain cost, mass, and energy consumption. AMTs can provide smooth shifts without torque interruption when coupled to a normally-open torque bypass clutch. However, conventional dry friction clutches are not best suited for such torque bypass due to wear and controllability concerns, while wet clutches would decrease powertrain efficiency due to viscous losses. An eddy current clutch would be highly controllable, simple to manufacture, low-cost, robust, and do not wear compared to friction clutches. The potential of eddy current clutches is assessed from a representative case study consisting of a ∼190 Nm clutch for a seamless two-speed AMT. The clutch design is based upon Wouterse's model, which is further refined using a Finite Element Analysis (FEA) on the clutch magnetic circuit. A prototype clutch is built and installed inside an existing AMT. The measured clutch coupling torque agrees well with Wouterse's model results, with a maximum error of 6%. The AMT performed seamless gear upshifts on a test bench thanks to the eddy current clutch, which confirms their viability for torque bypass.
Pouliot, Gabriel, Lacerte, Marc-Olivier, Plante, Jean-Sebastien, Micheau, Philippe
Application of Slope Sensor in Hill-Start to AMT (Automated Manual Transmission) Vehicles2015-01-11084/14/2015
In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock. In addition, it can also avoid backward sliding and engine over-speed effectively. Furthermore, hill-start with low-cost slope sensor and optimal clutch controller can reduce clutch wear, extend the life of dry clutch and improve the drivability.
Chu, Hongqing, Chen, Yong, Guo, Lishu, Gao, Bingzhao, Chen, Hong
Multi-Objective Optimization Employing Genetic Algorithm for the Torque Converter with Dual-Blade Stator2015-01-11194/14/2015
The traditional automotive torque converter (TC) is equipped with a single-blade stator, at the suction side of which there is an apparent boundary layer separation at stalling condition because of its large impending angle. The separation flow behind the suction side of stator blade is found to create large area of low-energy flow which blocks effective flow passage area, produces more energy losses, decreases impeller torque capacity and transmission efficiency. It is found effective to suppress the boundary layer separation by separating the original single-blade stator into a primary and a secondary part. The gap between them guides high-energy flow at the pressurized side of the primary blade to the suction side of the secondary one, which helps to make boundary layer flow stable. As a result, the impeller torque capacity and torque ratio at low-speed ratio increase tremendously at the cost of little drop of maximum efficiency. The original matching property between the torque converter and the engine is changed with the increase of impeller torque capacity of the dual-blade stator TC. Furthermore, the Genetic Algorithm(GA) is utilized to optimize matching relation of blade angles among each runner based on the presented modified one-dimensional flow model, and the Pareto frontier with stalling torque ratio and maximum efficiency of the dual-blade stator TC considered is obtained at the premise of unchanged original torque capacity. The new Pareto frontier is improved significantly compared to that of the single-blade one.
Wu, Guangqiang, Wang, Lijun
Integrated Control Strategy in the Power-On Upshift Process of Automatic Transmission Based on Transmission Output Torque2015-01-02314/14/2015
Gear-shift process of automatic transmission (AT) can be achieved with hydraulic control system which operates clutches or brakes' engagement or disengagement. According to the state of engagement elements, gear-shift process can be divided into torque phase and inertia phase. This article analyses gear-shift process of automatic transmission with the lever analogy and got the variation of the transmission's output torque. Then, the control principle of clutch to clutch shift is studied. This article takes power on up shift as study example and minimum of transmission output torque fluctuations during shifting as control target. Then this article analysis two control principles including inertia phase engine & transmission integrated control principle and entire shift process engine & transmission integrated control principle. For the factors that affect shifting during different stages and the characteristics of different shift control principles, clutch pressure observer based on input-to-state stability (ISS) is designed and applied to the entire shift process engine & transmission integrated control principle. Finally, the proposed control principle is applied on the vehicle simulation platform, Simulation results are compared to the results of power-on up shift without engine & transmission integrated control and integrated control strategy based on the transmission output torque observer which is designed based on the torque converter model. It is proved that the transmission output torque overshoot peak with inertia phase engine & transmission integrated control strategy is decreased significantly and shifting jerks are reduced. Shift quality is improved significantly.
Wei, Qingkai, Lei, Yulong, Li, Xingzhong, Hu, Boqin, Liu, Zhengwei, Song, Bin
Generic software architecture for cost efficient powertrain electrification2015-01-16304/14/2015
Hybrid-electric vehicles provide additional functionality compared to conventional vehicles. So-called ‘hybrid’ software functions are required to coordinate the conventional powertrain control and these additional control functions. A key factor to reduce the fuel consumption lies in optimal control of the entire interconnected powertrain. This paper aims to provide a framework for efficient interface definition, connection and coordination of control units for hybrid electric vehicles. Such a framework supports an efficient development of control unit architectures and the distribution of software functions. The generic approach necessitates modular software functions. It defines the distribution of these functions in control units optimized with respect to reuse, interfaces and compatibility with different powertrain topologies and electrification variants, especially also considering compatibility with a conventional powertrain and its electric hybridization.
Ebner, Wolfgang, Stolz, Michael, Bachinger, Markus, Korsunsky, Evgeny
Model-Based Optimization for an AMT Clutch Control during the Vehicle Starting2015-01-01614/14/2015
With the continuous growth in the emission requirements and higher riding comfort demand, the shift quality becomes more and more an important evaluation index of the automated transmission control algorithms. Traditionally, the shift quality is assessed subjectively by the driver's feeling and then adjusted based on the calibration engineer experience. This classical calibration has disadvantages, such as low reproducibility of the shifting event and a high dependence on the driver's driving habit, so here a model-based multi-objective optimization method is proposed, and the optimization of the clutch control parameters during the vehicle starting is used as an example. Firstly, a Modelica® based vehicle model is introduced. A second-order sliding mode control is applied to track the clutch position trajectory. The clutch engagement point and the clutch engagement speed in the slipping stage are taken as the optimization objects. The shift quality, clutch engagement duration and mean longitudinal jerk during the vehicle starting, are taken as the evaluation criteria. An evolutionary multi-objective optimization method (non-dominated neighbor immune algorithm, NNIA) is chosen to find out the optimal control parameters. Finally the optimal clutch control parameters are determined based on a proposed mathematical function in different accelerator positions, and the testing results show that the optimized clutch control meets the driver's requirements in different conditions.
Huang, Hua, Di, Di, Chu, Yuqiang, Guehmann, Clemens
General Motors Front Wheel Drive Seven Speed Dry Dual Clutch Automatic Transmission2015-01-10934/14/2015
General Motors has introduced a new front wheel drive seven speed dry dual clutch automatic transmission in 2014. The 250 Nm input torque rated gear box was designed and engineered for a global market in both front wheel drive and all-wheel drive configurations. The transmission has integrated start/stop capability enabled by the use of an electric motor driven pump and a pressurized accumulator. The architecture selected was chosen for optimization of packaging, fuel economy, mass, shift pleasability, and NVH. High mileage durability and world class drivability were the cornerstone deliverables during the engineering and design process Fuel efficiency is estimated to be 3% - 10% improvement over a conventional six speed automatic transmission. FWD variant wet mass of 78.1 kg was achieved through the rigorous engineering processes used to optimize the transmission system.
Clark, Kirby S., Singh, Tejinder, Buffa, Ronald P., Gayney, Jack M., Cousins, William L., Xie, Zhe, Moorman, Steven P., Wilson, Alexandria, Fannin, Michael P., Graham, Mark L., Preston, Christopher B., Solt, Michael B., Varda, David J., Gilmore, Mark R., Foulkes, Martin G., Risko, Rebecca K.
Comparison of Powertrain System Configurations for Electric Passenger Vehicles2015-01-00523/10/2015
Electric vehicles (EV) are considered a practical alternative to conventional and hybrid electric passenger vehicles, with higher overall powertrain efficiencies by omitting the internal combustion engine. As a consequence of lower energy density in the battery energy storage as compared to fossil fuels powered vehicles, EVs have limited driving range, leading to a range phobia and limited consumer acceptance. Particularly for larger luxury EVs, electric motors with a single reduction gear typically do not achieve the diverse range of function needs that are present in multi-speed conventional vehicles, most notably acceleration performance and top speed requirements. Subsequently, multi-speed EV powertrains have been suggested for these applications. Through the utilization of multiple gear ratios a more diverse range of functional needs can be realized without increasing the practical size of the electric motor. The major limitation of multi-speed EV powertrains is that the increased transmission complexity introduces additional losses to the vehicle. Through a number of simulations this paper studies the integration of multispeed transmission with EV platforms. Particularly, it investigates the performance improvements of both B and E class vehicle platforms realized through utilization of two and three speed transmissions. Also the potential application of hybrid energy storage systems (i.e. batteries combined with super-capacitors) is studied. Results demonstrate that there can be significant benefits attained for both small and large passenger vehicles through the application of multi-speed transmissions. However, optimization of these ratios must be considered in the analysis.
Walker, Paul D., Roser, Holger, Zhang, Nong, Fang, Yuhong
Controls Development and Vehicle Refinement for a 99% Showroom Ready Parallel Through the Road Plug-In Hybrid Electric2014-01-290610/13/2014
This paper details the control system development process for the University of Washington (UW) EcoCAR 2 team over the three years of the competition. Particular emphasis is placed upon the control system development and validation process executed during Year 3 of the competition in an effort to meet Vehicle Technical Specifications (VTS) established and refined by the team. The EcoCAR 2 competition challenges 15 universities across North America to reduce the environmental impact of a 2013 Chevrolet Malibu without compromising consumer acceptability. The project takes place over a three year design cycle, where teams select a hybrid architecture and fuel choice before defining a set of VTS goals for the vehicle. These VTS are selected based on the desired static and dynamic performance targets to balance fuel consumption and emissions with consumer acceptability requirements. The UW team selected a Parallel through the Road hybrid architecture due to its combination of performance capabilities, high power path efficiency, and reliability due to separated electric and biodiesel powertrains. Over the course of the three year competition, the controls team developed a number of primary operating modes and strategies to control these powertrains. The different modes are examined in detail, along with how various software testing methodologies were used to validate the safety and performance of the vehicle in simulations. Key improvements in Year 3 are examined, in addition to investigating their effects on the vehicle's ability to meet VTS goals set by the team. Many validation tests were conducted using dynamometer testing at Argonne National Labs, which showed that the vehicle would be able to meet the majority of VTS goals during the Year 3 Competition Dynamic Events.
Crain, Trevor, Mallory, Michael Ryan, Cawley, Megan, Fabien, Brian, Reinhall, Per
Challenges and Opportunities in Variant Calibration of Hybrid Vehicles2014-01-288910/13/2014
The automotive industry is racing to introduce some degree of hybridization into their product ranges. Since the term “hybrid vehicle” can cover a wide range of differing technologies and drivetrain topologies, this has led to a large amount of vehicles that call themselves “hybrid”. This poses an interesting challenge for marketers to differentiate these vehicles from the incumbents. However, it is not just the marketers who are faced with challenges, the developers of such hybrid drivetrains are faced with a rise in technical complexity due to the wide range of operating modes hybridization introduces. As propulsive torque is being generated in more than one place in a hybrid vehicle, the transitions from conventional drive to electrically supported drive bring with them complex aspects of multi-dimensional system control. The challenge is to be able to implement hybrid technology in an existing drivetrain, while adapting the existing components as required. The functional variability of hybrid technology, however, permits a range of possible implementations and the control calibration tasks themselves need to be well structured concerning hand-over, traceability and robustness. The only way to manage this exploding complexity is to apply methodical approaches to the calibration task and employ partial test automation when developing hybrid vehicles. The key to handling the exploding complexity of hybrid drivetrains is to employ a systematic and methodical approach, which eliminates repeated loops of calibration effort. By combining special tools and methodologies used for calibration projects, the client's calibration targets of driveability, CO2 reduction, maximum battery lifetime, and safety in hybrid vehicles can be achieved by both efficiency improvements and increased quality.
Kokalj, Gerhard, Schatz, Patrick, Zach, Christoph
Investigation of NVH Characteristics of a Downsizing Vehicle2014-01-20426/30/2014
The automotive industry permanently enhances Downsizing concepts due to environmental commitments and energy consumption concerns. Even in the category of city- and supermini-cars, great efforts are made for the development of highly charged engines with small displacement. So far the main focus of these developments is set on the reduction of CO2 emissions and fuel consumption. However these are not the only aspects, which have to be fulfilled by the vehicle in order to meet the demands of the customers and to be successful in competition. The NVH characteristics of such Downsizing vehicles have to match a class-specific level, which can only be achieved by additional measures. Regarding this, a view of the dynamic behavior of the entire vehicle is required. At the Institut für Kraftfahrwesen Aachen (ika) the potential for reducing fuel consumption and CO2 emissions of a Downsizing concept is investigated using a city-car as reference. For this purpose, among other things, the three-cylinder-engine of the reference car is replaced by a highly charged two-cylinder-engine with same power output but smaller displacement. Apart from the environmental aspects the NVH behavior of the Downsizing concept is investigated and optimized in a holistic approach including measurements and simulations. Focus of this paper is the analysis and the improvement of the NVH-phenomenon “shuffle”, which is excited by load change procedures of the two-cylinder-engine. With the help of a simulation model several measures for reducing “shuffle” are evaluated with respect to the acceleration of the vehicle. The measurements, the developed simulation model and the corresponding results are represented in this paper.
Elm, Jan Hendrik, Viehöfer, Jens, Biermann, Jan-Welm
Measurement and Modeling of Perceived Gear Shift Quality for Automatic Transmission Vehicles2014-01-91255/9/2014
This study was conducted to develop and validate a multidimensional measure of shift quality as perceived by drivers during kick-down shift events for automatic transmission vehicles. As part of the first study, a survey was conducted among common drivers to identify primary factors used to describe subjective gear-shifting qualities. A factor analysis on the survey data revealed four semantic subdimensions. These subdimensions include responsiveness, smoothness, unperceivable, and strength. Based on the four descriptive terms, a measure with semantic scales on each subdimension was developed and used in an experiment as the second study. Twelve participants drove and evaluated five vehicles with different gear shifting patterns. Participants were asked to make kick-down events with two different driving intentions (mild vs. sporty) across three different speeds on actual roadway (local streets and highway). After each event, participants were asked to complete the rating of the four descriptive terms as well as a comprehensive rating on the gear-shifting event. Along with this subjective evaluation, changes of mechanical properties during the event also were recorded. This included shift time and delay, acceleration profile, and jerk. Consequently, a series of statistical analysis revealed the relationship between each subdimension on subjective quality and their associated mechanical properties. Models of comprehensive shift quality, based on the ratings of the subdimensions for driving intentions and speeds, were also developed. The study provided a unique framework to assess subjective driving quality related to mechanical control variables in a multidimensional way, which is applicable to improve the quality of a vehicle.
Jeon, Byeong wook, Kim, Sang-Hwan
Research on Shift Control Strategy in Braking Conditions of Automatic Transmission Vehicles based on Fuzzy Inference2014-01-17424/1/2014
In a traditional shift control strategy, the gear range is selected based on the throttle opening and the vehicle speed. The disadvantage of two-parameter based system is that the shift map is lack of adaptability in certain special conditions. The driving environment and the true intentions of the drivers are not fully taken into account by the shift control system. Therefore, improving the feasibility of the shift control strategy for the true intentions of the driver and driving environment is of great significance. Under braking conditions, Automatic transmission shift map with two parameters is unable to use engine braking effectively, which affects the drivability and safety of vehicles greatly. This paper presents a newly developed shift control strategy under braking conditions. First of all, the necessity of engine braking was analyzed. Then, this paper proposed a shift control strategy based on fuzzy inference of braking duration, load, braking deceleration and the vehicle speed. The fuzzy inference system considers drivers' intentions and driving environment. Road tests indicated that the proposed shift control strategy improved driving safety of automatic transmission vehicle under braking conditions.
Fu, Yao, Lei, Yulong, Liu, Ke, Zhang, Yuanxia, Zeng, Huabing
Study of Power Losses in a Two-Speed Dual Clutch Transmission2014-01-17994/1/2014
This paper mainly studies the power losses in a refined two-speed dual clutch transmission which is equipped in a electric vehicle test rig. Both numerical and experimental investigations are carried out. After theoretical analysis of the power losses original sources, the developed model is implemented into simulation code to predict the power losses. In order to validate the effectiveness of the proposed model, results from experimental test are used to compare the difference the simulation and test. The simulation and test result agree well with each other. Results show that the power losses in the two-speed are mainly generated by multi-plate wet clutch drag torque and gear churning loss.
Zhou, Xingxing, Walker, Paul, Zhang, Nong, Zhu, Bo, Ruan, Jiageng
Development of Two Oil Pumping System for Automatic Transmission2014-01-17664/1/2014
The efforts to improve automatic transmission (AT) efficiency for vehicle fuel economy are constantly continuing. In an AT the oil pump is the largest power loss factor. Therefore the effect on fuel economy is very high. The AT oil pump system has structural contradictions (high pressure × high flow), and the efforts to improve these areas are concentrated. In this paper, a two oil pumping system was designed to improve the efficiency and performance of a 6 speed AT installed in a Hybrid Electric Vehicle (HEV) [1], and the improvement was confirmed by a prototype experiment. As a result of the experiment, two pumping system was shown to improve vehicle fuel economy while reducing noise and oil pressure vibration.
Hwang, Jin Young, Jo, Se Hwan, Wi, Tae Hwan, Son, Woo Churl
Simulations of Drag Torque in Multi-Plate Wet Clutch Affecting Synchronizers in a TC+AMT Transmission2014-01-17144/1/2014
Drag torque in multi-plate wet clutch consumes engine energy, but also has significant affect on synchronization process during shifting. The mathematical models of drag torque and shift synchronization process were established, and the results carried out by Matlab/Simulink simulation were compared with experiment results as well. It is demonstrated that the models are correct and accurate. The influences of friction pair gap in multi-plate wet clutch, cooling oil flow and properties of cooling oil under different temperature etc. on drag torque, shift synchronization time and energy were analyzed. The conclusions have certain guiding significance to the multi-plate wet clutch theoretical study and structural design as well as transmission system matching.
Sun, Shaohua, Lei, Yulong, Li, Xingzhong
Research on Intelligent Self-Learning System for the Electro-Pneumatic Automated Manual Transmission Gear Position2014-01-17414/1/2014
In the electro-pneumatic automated mechanical transmission (AMT) system, the manufacturing, assembly, wear, replacement and other issues often lead to gear position change and some differences in various gears of transmission, which reduces the success rate and even results in abnormally working. To solve these problems, based on the intelligent control theories of fuzzy PI control, this research developed an intelligent self-learning system for the AMT gear position. This system contains the position initialization module after assembling (offline module) and the position correction module in use (online module). The system can automatically recognize gear position deviation and actively correct it, which improves the robustness of shift actuator. The precise control of shift actuator is the key of this self-learning system. However, due to the compressibility of air and uncertainty of external flexible dynamics, it is difficult to establish accurate models of the system in each stage, so conventional PID control methods have been unable to accurately control the position of shift cylinder. In this study, the flow equation of shift valve is established based on analysis of the operating principles of electronically controlled pneumatic AMT, and then a fuzzy PI control strategy is developed according to fuzzy control theory. With the platform of pure electric car equipped electrically controlled pneumatic AMT, a series of field vehicle tests were carried out and the results showed that the development of intelligent AMT shift position self-learning system can effectively achieve self-learning of shift position accurately with good consistency and higher efficiency.
Sun, Shaohua, Li, Shunbo, Fu, Yao, Yang, Cheng
Development of a New Wet Dual Clutch Transmission Transmission and Driveline2014-01-17244/1/2014
To meet the requirements of low fuel consumption, good driving performance, vehicle packaging constraint, and manufacturing feasibility, a new wet dual clutch transmission family has been developed by SAIC Motor. This paper will provide a design overview of the transmission architecture, main characteristics, key subsystems and control strategies. The paper will also provide an overview of the development process, and the fuel economy benefit to the vehicle. The transmission family adopts compact layout of gears and shafts, wet dual clutch, hydraulic system for actuation of clutch and forks, integrated parking system, integrated fork and synchronizer system, etc. To achieve compact package target, a coaxial dual clutch with integrated damper system, two countershafts system, and optimized layout of gear system are adopted. The technical features for low fuel consumption include waved clutch plates, targeted cooling of wet clutch, optimized gear ratios, optimized control strategies. The technical features for high driving performance include optimized control on clutch pre-filling and clutch swap, close loop control on gear engagement, optimized control on different driving mode. The newly developed 6-speed dual clutch transmission was applied to the new ROEWE550 vehicle equipped with 1.8L turbo and 1.8L natural aspirated gasoline engines. The vehicle was launched to China market in the middle of 2013. The newly developed wet DCT improves not only vehicle dynamic performance, but also fuel economy, with above 5% acceleration improvement and above 8% fuel consumption reduction.
Jiang, Chao, Huang, Wenhua, Fang, Weirong, Xin, Jun
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