Browse Topic: Differential gears

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Development of New Hybrid Transaxle for Mid-Size Sports Utility Vehicles2020-01-08504/14/2020
Toyota has developed a new Hybrid (HV) transaxle P810 for Mid-Size SUVs to improve fuel efficiency and power performance. The transaxle was developed based on Toyota's new development strategy - Toyota New Global Architecture (TNGA). By adopting technologies to shorten overall length of the transaxle, installation into the same engine compartment of Mid-Size sedans have been realized while also improving the motor output. This paper will introduce technologies regarding the new mount structure for shortening overall length, and furthermore, noise reduction related to this mount structure.
Nobuyasu, Seitaro, Iwata, Shigetsugu, Nishigaya, Masabumi, Hagino, Yoshiteru, Ito, Masatoshi, Aihara, Hiroshi
Research on Tracking Algorithm for Forward Target-Vehicle Using Millimeter-Wave Radar2020-01-07024/14/2020
In order to solve such problems that the millimeter-wave radar is of large computation, poor robustness and low precision of the target tracking algorithm, this paper presents an algorithmic framework for millimeter-wave radar tracking of target-vehicles. The target measurement information outside the millimeter- wave radar detection range is eliminated by the data plausibility judgment method based on the millimeter-wave radar detection parameters. Target clustering is made using Manhattan distance, to eliminate clutter interference and cluster multiple target measurements into one. The data association is made by use of nearest neighbor to determine the correspondence between information received measured by the radar and the real target. The vehicle is the key detection target of the vehicle millimeter-wave radar during road driving. These target-vehicles generally have no vertical movement or small moving speed in the vertical direction, so only the movement of the target-vehicle in the XY plane needs to be considered. Since the target-vehicle motion state has the characteristics of small mobility, a constant acceleration model is established based on the millimeter-wave radar motion coordinate system to describe the motion state of the front target-vehicle. The motion state are tracked and optimized by the algorithm of improved adaptive extended Kalman filter (IAEKF), because it is difficult to determine the statistical property of its measurement noise. A differential position system is formed by installing a base station on the ground and RT3000s on the ego-vehicle and target-vehicle, respectively. Differential Position System is formed by installing Base Station on the ground and high-precision inertial navigator RT3000s and RT-XLANs on the ego-vehicle and target-vehicle, respectively. By use of the differential position system, with effective communication, the relative distance and speed information between both vehicles can be obtained in real time to verify the accuracy of the millimeter-wave radar target tracking algorithm. Results show the proposed algorithm is feasible and of high estimation accuracy.
Song, Shiping, Wu, Jian, Yang, Yu, He, Rui, Chen, Xuesong, Li, Xin
Modelling and Control of a Novel Clutchless Multiple-Speed Transmission for Electric Vehicles2019-24-00639/9/2019
Conventional electric vehicles adopt either single-speed transmissions or direct drive architecture in order to reduce cost, losses and mass. However, the integration of optimized multiple-speed transmissions is considered as a feasible method to enhance EVs performances, (i.e. top speed, acceleration and grade climbing), improving powertrain efficiency, saving battery energy and reducing customer costs. Perfectly in line with these objectives, this paper presents a patented fully integrated electric traction system, as scalable solution for electrifying light duty passenger and commercial vehicles (1.5-4.2 tons), with a focus on minibuses (<20 seats). The adoption of high-speed motor coupled to multiple-speed transmission offers the possibility of a relevant efficiency improvement, a 50% volume reduction with respect to a traditional transmission, superior output torque and power density. The proposed clutchless four-speed transmission is specifically conceived and designed to have the good matching with the traction electric motor. Indeed, clutches and synchronizers are not required thanks to the small inertia of the traction motor and its fast regulation in both torque and speed mode (torque modulation process). Therefore, an advanced shifting control system/strategy has been developed to reduce the time shifting, linked to the degree of jerk and the power interruption, guaranteeing the coordination of all the gear-shifting actuators despite the randomness of the gear shifting process. After the description of the system layout, the paper gives an insight of the plant dynamic model and its equations. The controller architecture along with its strategies are also presented. The effectiveness of the proposed solution is proven through an extensive set of simulations carried out for a vehicle running on a real driving cycle.
Malafronte, Ludovica, Grandone, Mauro, Lega, Alberto, Pennese, Michele, Pianese, Cesare
Development of an Analytical Method for Rear Differential Gear Whine Noise Utilizing Principal Component Contribution by OTPA and CAE2019-01-15556/5/2019
The progress of vehicle electrification has reduced engine noise and the improvement of rear differential gear whine noise has become more important for customer satisfaction. Rear differential gear whine noise is a result of the vibration generated by the transmission error of the gears transmitted to the cabin from various paths. As several components have a contribution, identifying key paths to develop an effective countermeasure becomes time consuming. Operational transfer path analysis (OTPA) is one of the TPA methods to determine the main path and contributing part using only the operational data. However, in cases where many reference points are set on the same frame or body, the contribution becomes similar because of high correlation between the reference data set. As a result, finding the main transfer path becomes difficult. To overcome this issue, the principal component (PC) contribution obtained from the correlated reference signals was established by modifying the OTPA process. Through this process, important vibration behavior of the target structure can be obtained as the high contributing PC mode. In this paper, this approach was applied to a vehicle and verified. In addition, for applying the method, enormous signals at the reference and response points are necessary to be recorded simultaneously. This issue makes the method difficult to be applied especially to the high frequency phenomenon. This issue was solved by using frequency responses calculated from finite element (FE) models which were converted to transient data by inverse fast Fourier transform (FFT). After obtaining sufficient amount of data by using simulation, the data was used to identify the high contributing PC modes and the vibration modes. Using these findings, the vehicle was retrofitted, the vibration and sound pressure levels were confirmed to decrease and the effectiveness of the developed method was verified.
Nakatsuka, Miho, Miwa, Tetsuya, Yoshida, Junji
Drivetrain Analysis and Optimization of a Two-Speed Class-4 Electric Delivery Truck2019-01-50011/18/2019
The development, analysis, and comparison of battery electric class-4 medium-duty trucks equipped with three possible powertrain layouts, namely, direct drive, single-speed gearbox, and two-speed transmission options, are discussed in this paper. The problem definition is included and the performance evaluation criteria for the proposed truck architectures are defined, namely, acceleration time, top speed, and efficiency. Designs of four new traction motors are proposed and their benefits compared for use in medium-duty electric trucks (e-trucks). The procedure for gear-ratio range selection is outlined, the ranges of gear ratios for the single-speed gearbox and two-speed transmission powertrains being calculated for each of the proposed electric traction motors. The simulation and gear-ratio optimization tasks for the e-trucks are formulated. The energy consumption of the e-truck with the three possible powertrain combinations is minimized over the six driving cycles. The most efficient powertrain layouts that meet the performance criteria are determined.
Morozov, Alexei, Humphries, Kieran, Rahman, Tanvir, Zou, Ting, Angeles, Jorge
Electric Vehicle with Multi-Speed Transmission: A Review on Performances and Complexities08-07-02-001112/4/2018
Electric vehicles (EVs) with multi-speed transmission offer improved performances compared to those with single speed transmission system in terms of top speed, fast acceleration, or gradeability along with driving range. In this study, relevant literature is extensively analyzed to explore the performances and associated complexities with multi-speed automatic manual/mechanical transmission (AMT) system in EVs. In EV powertrain, the only torque generator component is electric motor, which is not equally efficient throughout wider speed range. To the other end, vehicles need to run at different speeds in diverse driving conditions. The study shows that multi-speed transmission system enables efficient operation of electric motor by choosing an appropriate gear at different driving torque-speed demands and thus contributes to achieve desired vehicle performances at minimum energy consumption. To demonstrate the differences, both dynamic and economic performances with multi-gear system and single speed system are compared, and the results of various techniques are presented in the form of tables and bar charts. A quantitative analysis is also conducted to show the performance improvement achievable by employing multi-speed transmission concept in EVs. Apart from additional mass, gear ratio selection and torque interruption during gear shifting are major obstacles to improve drivetrain efficiency and riding comfort in EVs with multi-speed transmission system. For optimal gear ratio in transmission system, genetic algorithm (GA) is found to be implemented in most articles. It is also observed that variable shift schedule needs to be considered during the optimization process to get the paramount gear ratios. Tables and bar charts are used to show the results of recent relevant works to these issues. In this article, the readers would gain a comprehensive knowledge on how multi-speed transmission technology can outperform the single speed system within EV platform and what the inherent challenges are.
Ahssan, Md Ragib, Ektesabi, Mehran Motamed, Gorji, Saman Asghari
Efficient Component Reductions in a Large-Scale Flexible Multibody Model10-02-01-00013/5/2018
To make better use of simulations in the automotive driveline design process there is a need for both improved predictive capabilities of typical system models and increased number of variant evaluations carried out during system concept design phase. A previously developed large-scale multibody rotor dynamical powertrain model that combines detailed linear-elastic finite element components and nonlinear joints is used to more accurately simulate system response modes and their variations across the operating-range. However, the total simulation time is too long to include extensive parameter evaluations during the rapid design iterations, which will have a negative influence on the total understanding of the designed system's behaviour. Therefore this article is about reducing such a large-scale model to one that runs faster, but without losing the ability to predict the most fundamental system characteristics. Reduction methods considering defined stimuli-response relations are well established and used within the field of control systems, to balance prediction accuracy and evaluation effort, but are not yet commonly applied to large-scaled structural models and analysis of vibrations in continuous and lightly damped structures. Here, an implementation of two such state-space reduction methods into a common computational software workflow is described and their overall efficiency is compared to standard methods. Reductions are applied to two major structural components of the powertrain model. Steady-state simulations are performed for multiple engine speeds and responses related to vehicle noise and vibrations are compared using a quantitative error metric. The prediction accuracy, reduction and response simulation times of different model orders are evaluated, as well as the corresponding mode frequency spectra.
Andersson, Niclas S., Abrahamsson, Thomas
Development of Next Generation Gear Oil for Heavy Duty Vehicles2017-01-08903/28/2017
Heavy duty vehicles take a large role in providing global logistics. It is required to have both high durability and reduced CO2 from the viewpoint of global environment conservation. Therefore lubricating oils for transmission and axle/differential gear box are required to have excellent protection and longer drain intervals. However, it is also necessary that the gear oil maintain suitable friction performance for the synchronizers of the transmission. Even with such good performance, both transmission and axle/differential gear box lubricants must balance cost and performance, in particular in the Asian market. The development of gear oil additives for high reliability gear oil must consider the available base oils in various regions as the additive is a global product. In many cases general long drain gear oils for heavy duty vehicles use the group III or IV base oils, but it is desirable to use the group I/II base oils in terms of cost and availability. The main key technologies for group I/II oil-based gear oils are the additive components chosen and the formulation balance to achieve anti-wear optimum protection and extreme pressure conditions. This paper describes development focused on the evaluation of anti-wear and extreme pressure components using tests, the improvement of the extreme pressure properties, the provision of corrosion inhibition on the gear tooth surface, and the maintaining of friction properties for the synchronizers in the transmission. As a result, the lubricant gives durability and long drain interval performance, even blended in the group I/II base oils.
Nakamura, Yoichiro, Horikoshi, Masahisa, TAKEI, Yasunori, Onishi, Takahiro, Murakami, Yasuhiro, Hewette, Chip
Development of New Plug-In Hybrid Transaxle for Compact-Class Vehicles2017-01-11513/28/2017
To help respond to growing customer demand for environmentally friendly vehicles, a new transaxle for plug-in hybrid vehicles (PHVs) has been developed that achieves excellent fuel economy and ensures high performance when the PHV operates in electric vehicle (EV) mode. Under the basic concept of sharing a large number of parts with the transaxle in the all new Prius, the newly designed PHV transaxle was developed with the aim of enhancing EV power and range. To achieve our goal, the new transaxle uses a Dual Motor Drive System that operates the generator as a motor to supplement the existing motor. It also features an electrical oil pump (EOP) that improves cooling performance in EV mode. The developed transaxle helps to advance the PHV as a key next-generation environmentally friendly vehicle by maximizing the performance of the Toyota Hybrid System (THS) and achieving even better dynamic EV mode performance than the new Prius HV.
Suzuki, Yosuke, Nishimine, Akiko, Baba, Shinichi, Miyasaka, Kenji, Tsuchida, Michitaka, Endo, Hiroatsu, Yamamura, Norihiro, Miyazaki, Tomoyuki
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
Development of Shift Control System for Multi Stage Hybrid Transmission2017-01-11503/28/2017
Toyota Motor Corporation developed a new hybrid system, Multi Stage Hybrid System, for the Lexus flagship coupe LC500h with the aim of achieving an excellent balance between fuel economy and acceleration performance. The Multi Stage Hybrid Transmission used in this new hybrid system includes a shift device located immediately after the power split device and motor. Compared with previous hybrid systems, the new hybrid system improves fuel economy by reducing electrical loss in the optimal gears, which are selected depending on the driving state. The system also improves acceleration performance by increasing the driving force at low and medium vehicle speeds in lower gears. In addition, the range of the power split device that cooperates with the shift device was widened to enable both an electrically-controlled continuously variable transmission mode and a ten-speed transmission mode, which creates a direct shift feeling to improve driving pleasure. This system contains many independent variables given by the interactions of the engine, generator, motor, and shift device. Thus, conventional control methods were not appropriate for devising the shift control of the system. In addition, shift performance may also be affected by the particular constraints of a hybrid system, such as battery limitations. This paper describes the shift control system for the Multi Stage Hybrid Transmission that was developed to resolve these issues.
Kumazaki, Kenta, Matsubara, Tooru, Kobayashi, Nobufusa, Kato, Shunya, Shiiba, Kazuyuki, Ando, Ikuo, Kimura, Hiromichi, Endo, Hiroatsu
Bond Graph Based Approach for Modeling of Automatic Transmission Dynamics2017-01-11433/28/2017
This paper describes a method for modeling the dynamics of planetary automatic transmissions by using bond graphs. Bond graph models for the most relevant planetary gear sets (single, double and stepped pinion and Ravigneaux) are summarized and used as building blocks to construct the "device-mapping" bond graphs of complete planetary transmissions. Examples used include the legendary Ford Model T transmission and state-of-the-art six- and ten-speed transmissions. A systematic procedure of deriving mathematical models based on the constructed bond graph models is described which can be applied to any clutch application combination. It is illustrated how device-mapping bond graph models can be converted into conceptual torque-path bond graphs for better insight on the analysis of transmission shift events. Lastly, the effect of system rotational inertias on shift dynamics is discussed for practical concerns.
Ivanovic, Vladimir, Tseng, H. Eric
Low-viscosity Gear Oil Technology to Improve Wear at Tapered Roller Bearings in Differential Gear Unit2016-01-220410/17/2016
Torque loss reduction at differential gear unit is important to improve the fuel economy of automobiles. One effective way is to decrease the viscosity of lubricants as it results in less churning loss. However, this option creates a higher potential for thin oil films, which could damage the mechanical parts. At tapered roller bearings, in particular, wear at the large end face of rollers and its counterpart, known as bearing bottom wear is one of major failure modes. To understand the wear mechanism, wear at the rolling contact surface of rollers and its counterpart, known as bearing side wear, was also observed to confirm the wear impact on the tapered roller bearings. Because gear oils are also required to avoid seizure under extreme pressure, the combination of a phosphorus anti-wear agent and a sulfurous extreme pressure agent are formulated. Because the latter could cause an antagonistic impact on the former, we focused on control of active sulfur content as well as the treat ratios to reduce wear at the tapered roller bearing while maintaining anti-seizure. Additive screening bench tests were performed considering operational conditions in actual gear unit-stand tests on the basis of the above-mentioned concept and the best formulation was identified as a breakthrough for low-viscosity gear oil. This low-viscosity gear oil technology was validated in the unit-stand tests. The sample oil based on the technology demonstrated equivalent performance for anti-wear while maintaining good anti-seizure, to the high-viscosity gear oil.
Mori, Takafumi, Suemitsu, Masanori, Umamori, Nobuharu, Sato, Takehisa, Ogano, Satoshi, Ueno, Kenji, Kuno, Oji, Hiraga, Kotaro, Yuasa, Kazuhiko, Shibata, Shinichiro, Ishikawa, Shinichiro
Dynamic Substructuring for Sources Contributions Analysis in Internal Combustion Engines2016-01-17616/15/2016
For vibration and acoustics vehicle development, one of the main challenges is the identification and the analysis of the noise sources, which is required in order to increase the driving comfort and to meet the stringent legislative requirements for the vehicle noise emission. Transfer Path Analysis (TPA) is a fairly well established technique for estimating and ranking individual low-frequency noise or vibration contributions via the different transmission paths. This technique is commonly applied on test measurements, based on prototypes, at the end of the design process. In order to apply such methodology already within the design process, a contribution analysis method based on dynamic substructuring of a multibody system is proposed with the aim of improving the quality of the design process for vehicle NVH assessment and to shorten development time and cost. The methodology here proposed is applied to assess vibrational contributions of an internal combustion engine without considering the corresponding Frequency Response Functions (FRF). Hence, the different excitations of the system (e.g. combustion, piston-liner interaction, bearing contact forces, etc.) are directly applied on the investigated geometry and their contributions are computed through numerical simulation. A comparison of the influence on the overall vibrations of the different excitations acting on an I3 engine will be done for structural vibration paths. The applicability and the accuracy of the methodology is finally discussed with reference to experimental measurements of a V6 engine. Two variants of the engine are investigated: the main differences between the two engine variants, mostly associated with piston-liner interaction forces, are investigated at mid-low frequency main engine orders for the entire speed range at full load condition. The proposed methodology is performed to assess the influence of these differences in terms of acceleration level on the external surface of the numerical model of the engine.
Acri, Antonio, Offner, Guenter, Resch, Thomas, Nijman, Eugene, Corradi, Roberto
A Study of Axle Fluid Viscosity and Friction Impact on Axle Efficiency2016-01-08994/5/2016
The growing need for improved fuel economy is a global challenge due to continuously tightening environmental regulations targeting lower CO2 emission levels via reduced fuel consumption in vehicles. In order to reach these fuel efficiency targets, it necessitates improvements in vehicle transmission hardware components by applying advanced technologies in design, materials and surface treatments etc., as well as matching lubricant formulations with appropriate additive chemistry. Axle lubricants have a considerable impact on fuel economy. More importantly, they can be tailored to deliver maximum operational efficiency over specific or wide ranges of operating conditions. The proper lubricant technology with well-balanced chemistries can simultaneously realize both fuel economy and hardware protection, which are perceived to have a trade-off relationship. In this study, Isuzu light duty truck axle, which is used in one of the highest selling cab-over vocational trucks in the global market, was tested on a full-scale axle test stand. The test stand was equipped with three electric motors and equipped and axle temperature control system. Two fluids, a commercial fluid of SAE 85W-90 (Fluid-A, Group-I with conventional additive) and the candidate fluid of SAE 75W-90 (Fluid-B, Group-III and the viscosity index improver and the new additive) were compared in this testing. This work describes the impact of fluid’s viscosity grade, friction (or traction) and additive chemistry on axle efficiency and durability performance. Additionally detailed results and analyses of the full-scale axle testing results will be presented.
Hoshino, Takashi, Qureshi, Farrukh, Virostko, Nicholas, Schiferl, Elizabeth, Gajanayake, Ananda, Hiroki, Motoji, Higuchi, Tomoya, Ishizaki, Keita
Development of New Hybrid Transaxle for Compact-Class Vehicles2016-01-11634/5/2016
1 As the demand for so-called eco-cars has been increasing recently, new hybrid transaxle P610 has been developed to achieve outstanding fuel economy and an excellent driving performance. P610 was installed in the 4th generation Prius, the first car to implement TOYOTA's new development strategy, TNGA (Toyota New Global Architecture). In order to accomplish the goal, radical reduction of mechanical loss, size and weight, dual-axle motor structure are adopted to draw out the potential capability of the THS (Toyota Hybrid System) to the maximum extent possible. Furthermore, placing the compact power train low, which is realized by installed the PCU(Power Control Unit) on top of the transaxle, led to provide the low center of gravity of the vehicle and excellent driving performance.
Taniguchi, Makoto, Yashiro, Takahisa, Takizawa, Keiji, Baba, Shinichi, Tsuchida, Michitaka, Mizutani, Tatsuhiko, Endo, Hiroatsu, Kimura, Hiromichi
Experimental Study on Performance of a Parallel Diesel Hybrid Vehicle Retrofitted with a Single Planetary Gear Train as an Add-On Transmission2016-28-01542/1/2016
The paper describes major design choices and development process used to produce a prototype of a rear-wheel drive parallel hybrid electric vehicle. This diesel electric hybrid vehicle is different from other hybrid with regard to the powertrain. The paper focuses on the design, development and performance evaluation of this unique parallel diesel electric vehicle which is based on multimode hybrid powertrain comprised of a single planetary gear train as an additional transmission along with the manual gearbox of the conventional diesel vehicle and AC induction motor. The implementation of the new design enables to overcome many problems encountered in the traditional vehicles. Constant mesh spur type simple planetary gear set transmission is designed for the intended application. To demonstrate the practical applicability of the transmission and this hybrid configuration, one prototype vehicle is built integrating the transmission. The hybrid system makes it easy to retrofit existing vehicles because the changes required in the vehicle drivetrain are minimum. Unlike the conventional diesel engine, the hybrid vehicle provides significant additional functionality to the driver. Five modes of operation, namely, engine-only, electric-only, hybrid power mode, engine/charge and regenerative braking modes are possible in the developed hybrid vehicle. Even if one system (the electrical system or the IC engine) fails, still the vehicle would remain functional on the other system. Its driving performance, fuel economy and emissions are measured and results are analyzed over a given drive cycle .The results showed that the hybrid vehicle is about 30% faster than the equivalent conventional vehicle. The fuel economy is increased by 26% approximately compared to the conventional powertrain.
Gupta, Ajay Kumar, Kartik, V, Ramanarayanan, C P
Prospects for Future Non-Manual Transmissions Developments for Vehicle Applications in Brazil2015-36-03489/22/2015
The purpose of this paper is to present the origins and the technology of the different types of non-manual transmissions systems currently available and the wide potential to incorporate such technologies to the vehicles made in Brazil. The Brazilian market is experiencing a huge increase in automated and automatic transmissions vehicles share, and the OEMs are adopting different strategies to offer competitive products with affordable prices to enter in this segment. Many different alternatives are available, and there is no obvious winner. This paper will describe the concepts, the architecture and the operations of such systems and point out the pros and cons of each one.
Fornari, Rafael V., Yamada, Decio, Suzuki, Alexandre
Experimental Investigation of Effect of Driveline Torsional Fluctuations on Overall NVH Performance of the Vehicle2015-01-21926/15/2015
Meeting various customer(s) requirements with the given automotive product portfolio within the stipulated time period is a challenge. Design of product configuration matrix is an intelligent task and it requires information about vehicle performance for different configurations which helps in deciding the level of new development. Most often the situation arises, particularly in the field of NVH, to strike the right balance between engine power and structural parameters of the body. The sensitivity of engine power on the overall NVH behavior is the key information necessary to take major business decisions. In this paper, the effect of change in torsional fluctuation of the engine on the NVH behavior of the rear wheel drive vehicle is experimentally studied. The torsional fluctuation of the driveline is given as an input with the help of an electric motor to the existing test vehicle at its differential end and the current NVH levels are measured. A test rig is built to change the levels of torsional vibration input to the vehicle. The threshold level of torsional fluctuation for the given vehicle structure is obtained by taking into account the target values of tactile vibration and subjective perception. The results are very useful in deciding the acceptable level of change in engine power without carrying any structural change. Also, for a given power, the set of structural changes necessary in the body and suspension linkages to meet the NVH criteria can be studied. The procedure is also extended to an all-wheel drive vehicle with the help of a two wheel drive chassis dynamometer. Obtaining subjective perception of the vehicle NVH even before making the vehicle of target configuration is an inherent advantage of the proposed technique. A good correlation is achieved with the objective results and subjective perception.
Rao, Manchi Venkateswara, Frank, Jos, Raghavendran, Prasath
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.
Modular 7-Speed Hybrid Dual Clutch Transmission 7H-DCT2802015-26-00331/14/2015
The contribution presents a new structurally optimized 7-speed hybrid DCT for transverse applications. Advantageously the seven forward speeds can be provided with only two shafts. The space of the usually third shaft can be used for the electric motor or the mechanical reverse speed. This modular integration can be realized by using mostly identical parts for the components of the gear set and the transmission housing. The direct connection of the electric motor to the differential helps to avoid additional gear set loads and efficiency losses. Such modular transmissions will help in future to reduce development and production costs.
Leesch, Mirko, Müller, Jörg, Liebold, Jens
Novel Mechanism Using Differential Gears for the Electromechanical Brake2014-01-03844/1/2014
As is well known, the brake systems of vehicles are used in order to decelerate or stop the vehicle while the driving. The operational principle of the brake is the conversion of kinetic energy into thermal energy. In this case, the thermal energy is released to the atmosphere. Recently, electromechanical brakes (EMB) were developed in order to replace hydraulic brake calipers. Such brake-by- wire systems are composed of an electronic pedal, electronic control unit (ECU), wire, and an electromechanical caliper. A typical electromechanical brake is similar to existing floating brakes. In other words, an inner pad pushes out one side of a disc driven by the energy of a motor; by means of a screw-thread gear. Then, the caliper slides in the opposite direction by reaction force and moves the outer pad toward the other side of the disc. Then pads clamp both sides of the rotating disc and stop the wheel. While effective, this design has the problem that there is a difference in the wear of the inner and outer pads. In this paper, we describe a novel electromechanical brake design. Specifically, the proposed mechanism has some new features related to the presence of differential, and rack-pinion, gears. Furthermore, the wear difference of the inner and outer pads can be minimized by using our proposed mechanism. So to speak, both pads are clamped at the same time by the initial braking force. In addition, we focused on how to use the device to improve the braking force during the initial braking.
Park, Tae-Sang, Jin, Sungho, Moon, Jeon IL, Yang, Seung-Han
Design Improvement of Differential Casing through CAE Strain Correlation2014-01-07564/1/2014
A differential casing is one of the important elements in the vehicle power train, whose objective is to house differential gears and take different loads coming from these gears. The function of a differential is to drive a pair of wheels while allowing them to rotate at different speeds. While taking a turn, the outer wheel needs to travel more compared to the inner wheel. This is possible due to the differential which rotates them at different speeds. This Paper highlights a simplified methodology to capture the differential casing failure and to resolve the same. The methodology adopted was then correlated with the test measurements to increase the confidence. During physical tests, strains are measured at different orientations of the differential casing and correlated with simulation results.
Londhe, Abhijit, Kangde, Suhas, N, Sreenadh
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
Two-Speed Automatic Transmissions of Electric Scooters2013-32-908710/15/2013
To effectively reduce the greenhouse gas emission, electric scooters have been developed and become a booming green transportation around the world. Most of these electric scooters possess a fixed reduction ratio in the powertrain, which makes them far from satisfactory-you can't have low cost, high performance and efficiency at the same time. However, as a silver bullet, one kind of two-speed transmission is developed. The two-speed transmission will shift automatically according to speed and throttle. An exquisite design with of a one-way clutch as well as a synchronizer effectively reduces the inevitable shocks while shifting. The electric scooter with such two-speed transmission will be launched on the market in 2013. This product successfully reaches the concept of high performance, high efficiency and rather low cost. The performance data of this scooter (equipped with 12″ tire), according to the test pattern of Taiwan E-scooter (TES), are 174kg in weight (including 75kg for driver), gradeability 17.8 degrees (32.1%), maximum speed 55.7 km/h, and efficiency 43.4 km/kWh.
Chen, Kuo-ching, Chuang, Keng-tso, Liu, Han-hsueh, Chen, Ching-ya
Development of Continuously Variable Transmission Fluid for Fuel Economy2013-01-258410/14/2013
We develop a new metal-belt continuously variable transmission fluid (CVTF) named FE to improve fuel economy and help reduce CO2 emissions. FE is a low-viscosity fluid that reduces friction loss at low temperatures. Low-viscosity fluids generally reduce hardware durability, resulting in reduced metal fatigue life. Therefore, FE is designed for maintaining oil film thickness throughout the life of a vehicle by optimizing the base oil and viscosity modifier. FE also exhibits long-term anti-shudder performance that enables frequent use of controlled-slip torque converter clutches for improving fuel economy, represented by the flex start system, without decreasing torque capacity between the belt and pulley. The key point in the formulation of design is the selection of a suitable friction modifier. A friction modifier is an additive that improves friction properties. In this study, a suitable friction modifier selectively acts on friction papers as clutch material, not metals of belt and pulley surfaces, and provides a longer anti-shudder durability. In this report, we present the concepts behind setting the performance targets and the formulation of the design of FE. Metal-to-metal friction, anti-shudder performance, and friction properties of shift clutches of FE are also evaluated and compared with other commercial CVTFs.
Fukumizu, Takahiro, Yamashita, Minoru, Ogawa, Masashi, Nishinosono, Junichi, Sato, Takehisa, Ishibashi, Sakura
The Design, Development and Industrialization of an New 8 Speed Automatic Transmission in China2013-01-12774/8/2013
Shengrui Transmission Limited Corporate (Shengrui) has developed a new 8 speed automatic transmission (SR 8AT) for front wheel drive (FWD) vehicle. The concept of SR 8AT is unique and different from the conventional automatic transmission. The design of the SR 8AT system and components are new and compact. By combining an innovative gear train which is similar with the conventional manual transmission and the simple planetary gear structure, SR 8AT achieved 8 speed with the shortest length of the FWD transmission, the competitive fuel economy and the smooth shift performance among comparable automatic transmissions.
Lu, Jan Gang
The World's First Transverse 8-Speed Automatic Transmission2013-01-12744/8/2013
We have developed the world's first 8-speed automatic transmission for transverse FWD/4WD vehicles. The aim of this new automatic transmission was to achieve world-class fuel economy while offering both smooth gear shift and sporty shift feeling suitable for luxury cars. This has been accomplished using wide spread gear ratio, outstanding low drag components and highly efficient hydraulic control system. In addition, we have achieved the compactness similar to current 6-speed automatic transmission by adopting new gear train and compact clutch layout. In this paper, the detail of this automatic transmission is introduced.
Aoki, Toshihiko, Kato, Hiroshi, Kato, Naoki, Masaru, Morise
Development of Wheel Loader Dynamic Simulation Model2013-01-11944/8/2013
This paper presents a 3D dynamic simulation model of a wheel loader. The objective of development of the wheel loader dynamic simulation model is to investigate power flow under both working and driving conditions. The wheel loader dynamic simulation model consists of 3 parts: Vehicle mechanical powertrain module, Hydraulic modules for working and steering, and Vehicle dynamic module. Vehicle powertrain module consists of engine, torque converter and transmission. Hydraulic modules consist of pump, valve, cylinder and attachments. In this paper, hydraulic powertrain is managed only for steering system because this paper has been focused on dynamic analysis of mechanical powertrain and vehicle. Front and rear bodies are connected by pin in the center of steering system. Action/reaction forces and moments applied to the pin are calculated by solving front/rear dynamic simultaneous equations. Forces and moments at the pin are considered to analyze how they have an effect on the dynamics of wheel loader. The wheel loader dynamic simulation model is validated through real measurement, and it is shown that proposed dynamic simulation model can represent actual dynamics of wheel loader.
Oh, Kwang Seok, Yun, Seungjae, Kim, Hakgu, Yi, Kyongsu, Ko, Kyungeun, Kim, Panyoung
Nomenclature and Terminology for Truck and Bus Drive AxlesJ923_201207 (Current)7/2/2012
This SAE Recommended Practice outlines basic nomenclature in common use for truck and bus drive axle designs. Over a period of years there have been many different designs introduced; however, for this report, only the most common have been selected and only their general construction is illustrated to show the nomenclature of the various parts.
Truck and Bus Powertrain Committee
Configuration Design, Development and Experimental Validation of Two New Powertrains for Parallel Hybrid Electric Vehicle2012-28-00241/9/2012
Hybridization of a light duty diesel vehicle based on two new different power train concepts for a parallel hybrid vehicle is discussed. The paper focuses on the design, development and performance evaluation of two new parallel HEV power trains. The diesel electric hybrid vehicles are different from other hybrids with regard to the power train. Two new hybrid drive-trains namely, a post-transmission architecture using an additional simple PGT, and a coupled PGT based parallel hybrid transmission are designed. To demonstrate the practical applicability, two research prototypes equipped with these power trains are built with the same degree of hybridization. The implementation of the new designs enables to overcome many problems encountered in the traditional vehicles. Among the various control strategies, a rule based control strategy is considered for the hybrid vehicles. The prototypes of hybrid electric vehicle are tested on chassis dynamometer and test tracks. Drive cycle used for testing of the vehicle is also discussed. Test results are analyzed and compared to an emulated diesel vehicle. The performance parameters include fuel consumption, mass emission, maximum speed and vehicle acceleration. Possible modes of operation in the intended configurations are also stated. Even if one system (the electrical system or the IC engine) fails, still the vehicle would remain functional on the other system. Based on this study, hybrid powertrain strategies for future vehicles are proposed.
Gupta, A. K., Ramanarayanan, C. P., Amarnath, C., Seth, B.
Lightweight Differential2011-36-010510/4/2011
For environmental issues, the Automotive Industry is always looking for opportunities in terms of weight and size reduction. This consequently results in fuel consumption reduction. This new concept is more compact, lighter, quieter, more efficient and with higher performance. These attributes are possible by a completely new differential design. The architecture of this space-saving component is completely different from traditional differential designs. Instead of using conventional differential pinions, the Lightweight Differential has spur gears arranged as a planetary gear set in one plane, as used in automatic transmissions. This means that the required space and weight are significantly reduced and the potential torque capacity is noticeably increased. The lightweight or spur gear differential has enormous advantages. It's possible to save up to 30 percent weight compared with a classic bevel gear differential while creating up to 70 percent more axial space due to the streamlined design. In specific terms this means a reduction in mass of up to three kilograms per differential and 90 millimeters of additional space in the transmission. The Lightweight Differential is an appropriate response to the challenge of increasing engine torques and the space gained in the transmission creates more room for larger double clutches or transfer boxes, as well as electronic components for modern hybrid solutions.
Hosokawa, Ricardo Shindi, Stevaux, Roberto, Martins, Alessandro
The Development of New Hino Hybrid Commercial Vehicles2011-01-21969/13/2011
In 1991, Hino Motors, Ltd. (Hino) launched the world's first hybrid city buses in the market. Thereafter, Hino has improved its hybrid vehicle technology and applied it to various commercial vehicles including city buses, sightseeing buses, medium-duty trucks and light-duty trucks. Recently, Hino has developed light-duty hybrid trucks, whose fuel efficiency has improved by 50% relative to its Diesel trucks. The significant improvement in fuel efficiency is achieved by four improvements in hybrid trucks. First, the hybrid system is improved: the change in the drive train layout, the relocation of a clutch, makes it possible to recoup the regenerative energy more efficiently. Second, the vehicle is also improved by the new hybrid engine, the reduction of the rotation speed of the engine during idling, and the improvement in the differential gear ratio. Third, new hybrid system controls are developed to bring benefits of the hybrid system to all drivers. Forth, low-cost but efficient units are developed to make fuel efficient hybrid vehicles prevail in the market. This paper discusses new Hino hybrid vehicle technologies developed for the light-duty trucks.
Suzuki, Shigeru
Passenger Car and Light Truck AxlesJ2200_201109 (Current)9/6/2011
This SAE Recommended Practice is intended to outline basic nomenclature for axle designs in common use for automotive drives. Over a period of years, there have been many different designs; however, for the purpose of this report, only the most common designs have been selected and only their general construction is illustrated to show the nomenclature of the various parts.
SAE IC Powertrain Steering Committee
Clutchless Geared Smart Transmission2011-01-20318/30/2011
Most passenger vehicles employ manual or automatic transmission in their power train. Recently, some automated geared transmission including the dual clutch transmission is gaining popularity for its fuel efficiency and smooth driving as well as convenience. In this study, we are proposing a new much simplified clutchless geared transmission which may transmit most powerful torque employing the power-merge planetary gear system to the final drive during gear shift with excellent smoothness in the transmitted torque. This transmission might work for the most kinds of vehicles having internal combustion engine including the hybrid vehicles.
Yoon, Yong-San, Kim, Kyung Soo, Kim, Sun Je
Factors Affecting Accuracy of Mechanically Driven Automotive Speedometer-OdometersJ862_201108 (Current)8/5/2011
This report is concerned with factors which affect accuracy of distance indication and speed indication of automotive type odometer speedometers. It is the intent to supply information regarding all items which affect the instrument.
Odometer and Speedometer Standards
New Drivetrain for Toyota's Flagship Lexus LFA Sports Car2011-01-14274/12/2011
Toyota Motor Corporation has developed a new drivetrain for their flagship Lexus LFA sports car. Passionate driving experience was pursued at the forefront of development. Superior vehicle performance, handling, and responsiveness that seem to anticipate the driver's intentions are achieved. Special vehicle packaging and component placement are adopted in the LFA in order to realize such performance. The engine, clutch, and front counter gear are positioned at the front of the vehicle, and the transaxle at the rear. The engine and transaxle are connected by a rigid torque tube. The transaxle is an automated manual transmission equipped with an electrohydraulic actuator for controlling both the shift and clutch operations. This actuator enables accurate control of the transmission and extremely quick response to shift paddle operation by the driver. This paper describes a general outline of the drivetrain and each component that has significantly contributed to LFA product appeal.
Kobayashi, Takahide, Masaru, Morise, Kano, Tomoyuki, Imafuku, Mizuki, Yamada, Masanobu
Next Generation Torque Control Fluid Technology, Part IV: Using a New Split-μ Simulation Test for Optimizing Friction Material-Lubricant Hardware Systems2010-01-223010/25/2010
Wet clutch friction devices are the primary means by which torque is transmitted through many of today's modern vehicle drivelines. These devices are used in automatic transmissions, torque vectoring devices, active on-demand vehicle stability systems and torque biasing differentials. As discussed in a previous SAE paper ( 2006-01-3271 - Next Generation Torque Control Fluid Technology, Part II: Split-Mu Screen Test Development) a testing tool was developed to correlate to full-vehicle split-mu testing for limited slip differential applications using a low speed SAE #2 friction test rig. The SAE #2 Split-Mu Simulation is a full clutch pack component level friction test. The purpose of this test is to allow optimization of the friction material-lubricant hardware system in order to deliver consistent friction performance over the life of the vehicle. In this paper we will describe the development of a new test based on the previous work including equipment modifications, data analysis and correlation to full-vehicle split-mu testing. This new tool allows the validation of new friction modifiers tailored to OEM-specific friction materials.
Whitticar, David, Basu, Shubhamita, Greene, Galen, Henley, Matthew, Parham, Dwight, Prengaman, Christopher, Schiferl, Elizabeth, Baker, Mark, Bartley, Stuart, Huston, Michael E.
Evaluation of NOx and Fuel Consumption Reduction Potential of Parallel Diesel-Hybrid Powertrains using Engine-In-the-Loop Simulation2010-32-01289/28/2010
Turbocharged diesel engines are popular propulsion systems for automotive applications like trucks or passenger cars because of their high efficiency and advantageous torque characteristic. The high NOx emissions due to their combustion process and missing three-way catalyst are, however, a disadvantage. Consequently, to satisfy future emission legislations, NOx emissions must be reduced. In addition, growing environmental awareness requires reduction of CO2 emissions, respectively, consumption. Hybridization is an effective method to achieve these multiple goals. The general tendency in direction of electrification of the powertrain leads to a diversity of drive concepts. In this context, the study of the entire system is as important as the analysis and evaluation of the interaction of the system components. The development of an intelligent control strategy managing the different operating states like stop/start, braking energy recuperation, load point shifting and electric driving is fundamental, too. Simulation is a powerful tool for these purposes and allows exploring different configurations of powertrains without cost-intensive and time-consuming production of prototypes. An appropriate approach to improve the accuracy of the results is the replacement of a virtual component in the simulation model by real hardware (Engine-in-the-Loop EIL). Thus, the real diesel engine is in interaction with the virtual powertrain and both operate in real time. A closed loop control is created where real hardware operates with virtual model components via defined interfaces. This paper shows how at the Institute for Powertrains & Automotive Technology (IFA) of the Vienna University of Technology intelligent control strategies were developed enabling the reduction of NOx emissions by up to 35% and the consumption by up to 15% by means of a parallel diesel-hybrid powertrain. Furthermore, different hybrid powertrain concepts were analyzed with the aim of demonstrating their advantages and disadvantages concerning the achievement of these goals. In this context, the method of the EIL simulation, used to obtain a high accuracy of the results, is described as well.
Teiner, Philipp, Schneeweiss, Bernhard
Acoustics of Hybrid Vehicles2010-01-14026/9/2010
The technology used in hybrid vehicle concepts is significantly different from conventional vehicle technology with consequences also for the noise and vibration behavior. In conventional vehicles, certain noise phenomena are masked by the engine noise. In situations where the combustion engine is turned off in hybrid vehicle concepts, these noise components can become dominant and annoying. In hybrid concepts, the driving condition is often decoupled from the operation state of the combustion engine, which leads to unusual and unexpected acoustical behavior. New acoustic phenomena such as magnetic noise due to recuperation occur, caused by new components and driving conditions. The analysis of this recuperation noise by means of interior noise simulation shows, that it is not only induced by the powertrain radiation but also by the noise path via the powertrain mounts. The additional degrees of freedom of the hybrid drive train can also be used to improve the vibrational behavior. As an example it is shown with a multi-body simulation of the drive train how its low frequency vibrations can be reduced with a targeted control of the electric motors.
Eisele, Georg, Wolff, Klaus, Wittler, Michael, Abtahi, Roozbeh, Pischinger, Stefan
Development of a parallel hybrid electric vehicle2009-28-004512/13/2009
This paper describes the development of a prototype parallel hybrid electric vehicle (HEV). Parallel configuration of HEV is achieved through an epi-cyclic transmission. A single stage epi-cyclic transmission is designed, developed and integrated into a vehicle equipped with conventional manual transmission. An internal combustion diesel engine and an electric motor are connected through epi-cyclic transmission to the propeller shaft of the vehicle. This parallel HEV provides five basic modes of operation namely engine mode, electric mode, power mode, engine/charge mode and regenerative braking mode. Each of these modes is obtained with the help of an electromagnetic clutch and brake integrated in the epi-cyclic gearbox. The selection of a mode depends upon the requirements of the vehicle. A feasible clutching logic and control strategy of parallel HEV is developed for operation of the vehicle in city, highway and high power requirement conditions. The advantage of such hybrid electric vehicle is that the performance of parallel HEV on engine mode is almost the same as that of the unmodified vehicle while it is also capable of purely electric low speed operation including launch from rest. The operational flexibility and better performance of the developed hybrid vehicle makes it a good choice for a parallel HEV.
Gupta, Ajay Kumar, Landge, B A, Seth, Bhartendu
Heavy Truck Driveline Components Modeling and Thermal Analyzing2009-01-290510/6/2009
In heavy truck driveline system, the components often include clutch, transmission, transfer case, drive shaft, etc. A fluid torque converter could be equipped in front of the transmission in order to improve the starting performance. Meanwhile, a hydraulic retarder could be introduced for auxiliary braking so as to adapt the truck to the brake on long downgrade in mountainous regions. Thus, the driveline heat load would have a notable increase. Both the fluid torque converter and the hydraulic retarder would produce a large quantity of heat, and a special cooling system is needed for adjusting the transmission fluid temperature with which the gains are potentially very large [1]. The heat load for driveline is often calculated based on empirical formula. For the heavy truck, however, if the heat value is underestimated, driveline components would suffer from overheated damage. On the other hand, if the heat value is overestimated, it will lead to the oversize radiator and affect the underhood arrangement. In this paper, we focus in the heavy truck with the gross vehicle weight of 80,000 kg, which is equipped with the fluid torque converter and the hydraulic retarder. The driveline model is built based on 1D simulation tool. The heat load of each primary heating component is calculated referring to the existing driving cycle and combining with the actual driving condition of the truck. On these bases, the parameters and the layout of cooling devices (such as the oil cooler) could be set for the heavy truck working properly in different driving conditions.
Tan, Gangfeng, Guo, Xuexun, Wang, Bin, Yan, Jun
Torque Converter-type High Fuel Economy CVT for Small Passenger Vehicles2009-01-15414/20/2009
A newly developed 1.3L, 1.5 L class CVT with a torque converter was mounted in the second generation FIT, which is aimed at realizing both higher fuel economy and exhilarating acceleration performance. As the main technologies used in the new CVT, a torque converter was used for a start-off method, an oil pump driven with small radius rotors via a chain and a structure with the bearing was mounted on the drive pulley cover. Particularly, as a type of fuel economy enhancement technology, the distance between two pulleys was increased, thus reducing friction torque. Also, creep control was used to enhance idling fuel economy, and start-off lockup clutch control was used to enhance launch fuel economy. As a result of these technologies, the transmission efficiency was 1.7% higher than that of the previous FIT CVT, and torque amplification effect of the torque converter during launch enabled achievement of higher fuel economy and exhilarating acceleration performance.
Yamaguchi, Masaaki, Ootaki, Mitsurou, Ito, Keisuke, Nirasawa, Hideo, Totsuka, Hirohiko
Lean Cr Containing PM Materials for Optimized Cost-Performance2008-32-00749/9/2008
Cr containing PM steels aid optimization of cost-performance for power transmission components in hydrostatic transmissions. Components such as final drive gears and differential gear sets are typical manufactured from sintered materials containing high levels of alloying elements such as Cu, Ni and Mo. Utilisation of Cr-Mo PM materials presents materials with improved cost - performance ratio via improved materials properties combined with improved dimensional tolerances.
Milligan, David, Howe, Ian, Haberberger, Thomas, Cerini, Richard
Jam-Free, Fail-Safe Flight Control System with Asymmetric Load Alleviation Capability2008-01-22638/19/2008
A dual cable flight control Driving System presented here functions the same way as current flight control systems in normal operation. However, if a jam occurs this System automatically transfers the command to the non-jammed side without pilot’s intervention. It enables either pilot to continue controlling the aircraft despite jamming, with no extra effort, no delay in action, and no threat of over-controlling the aircraft as a result of jamming. Current designs always require pilot’s action involving critical time delays in controlling the aircraft. For the same flight regime this System retains the same pilot effort force and the same cockpit control deflection as the non-jammed system. If unjamming occurs (icing condition) it automatically reverts back to normal operation without any pilot’s intervention. In normal operation the System is able to automatically balance-out asymmetric loads between surfaces thus leading to some load reduction and possible weight saving. It is also fail-safe.
Djuric, Mihailo (Mimi) P.
Two-Degree-of-Freedom Controller Design for Clutch Slip Control of Automatic Transmission2008-01-05374/14/2008
To improve shift quality of vehicle with clutch-to-clutch gear shifts, a two-degree-of-freedom controller, including a clutch pressure estimator, is designed for clutch control during the inertia phase of the shift process. The controller is designed based on a low order linear model which is derived from dynamics of the proportional pressure control valve and the vehicle drive line. Then the calculated controller is evaluated on the constructed nonlinear powertrain simulation model. Simulation results show that the rotational speed difference clutch can track the desired trajectory well, and shock can be reduced by designing suitable feedforward compensator.
Gao, Bingzhao, Chen, Hong, Sanada, Kazushi
Block-oriented Models of Torque Gap Filler Devices for AMT Transmissions2008-01-06314/14/2008
Vehicles equipped with Automated Manual Transmissions (AMT) for gear shift control show many advantages in terms of reduction of fuel consumption and improvement of driving comfort and shifting quality. In order to increase both performance and efficiency, an important target is focused on the minimization of the typical torque interruption during the gear shift, especially in front of the conventional automatic transmission. Recently, AMT are proposed to be connected with planetary gears and friction brakes, in order to reduce the torque gap during the gear change process. This paper is focused on a block-oriented simulation methodology developed in Matlab/Simulink/Stateflow® environment, able to simulate the performance of a complete FWD powertrain and in particular to predict dynamic performance and overall efficiency of the AMT with innovative Torque Gap Filler devices (TGF). A comparison between traditional Manual Transmission (MT) system and AMT with TGF device is presented, focusing in particular on the gear shift control strategies able to improve the performance of these systems. Some dynamic simulations are discussed in order to validate the proposed model and to simulate performance and limitations of this mechanical solution.
Velardocchia, Mauro, D'Alfio, Nicolò, Bonisoli, Elvio, Galvagno, Enrico, Amisano, Fabrizio, Sorniotti, Aldo
Development of Active-Front-Steering System (Differential Gear Type)2008-01-05004/14/2008
We have developed a new active-front-steering system which contributes to the vehicle safety improvement. This system includes two motors and differential gear unit in one body. It makes possible to compensate steer angle and control reactive torque simultaneously. This means driver assistance control without interference on driver. This concept has a potential to omit tuning process on each vehicle, and reduce weight and cost. We have proved the effect of driver assistance control by this system.
Yamanaka, Kosuke, Nakano, Shirou
Electrical Variable Cam Phase Shifter for Internal Combustion Engine2008-01-13514/14/2008
This paper presents a new concept for an electro-mechanical cam phase shifting device (eCPS) along with its control structure. The proposed eCPS features a positive differential gear mechanism with a unique self-locking characteristic. Proof-of-concept simulations were performed using both ADAMS and Simulink analysis tools to evaluate the validity of the concept and its performance. Comparisons with other cam phasers were also discussed. Results confirmed the frictional locking mechanism which not only allows for reduced control effort but also provides the system with an important fail-operational feature. The frictional locking mechanism significantly reduces the reliability burden upon the electric machine. It was indicated that eCPS compares favorably with hydraulic cam phasers in shifting range, position holding, slew rate, system stiffness and power consumption. The performance of eCPS is independent from engine performance characteristics and environmental conditions.
Ai, Xiaolan, Wilmer, Matthew, Remboski, Donald
Development of a New Fuel-Efficient Manual Transmission Oil2007-01-397310/29/2007
Reducing the viscosity of a manual transmission oil is the most effective way to obtain a fuel economy effect with the lubricant. However, there are concerns that a lower viscosity may result in a thinner oil film, causing a decline in extreme pressure performance (anti-seizure and anti-wear performance) and anti-pitting performance at the high temperature condition. Therefore, a method for maintaining sufficient oil film thickness is needed for oils with reduced viscosity. In this study, attention was focused on the effects of the base oil and the viscosity index improver. As a result, a new manual transmission oil has been developed that provides an oil film thickness equal to that of current oil even though its viscosity has been reduced by half compared with the level of current oil. Specifically, the base oil is formulated with a high-viscosity mineral oil (Group I) and the molecular weight of the viscosity index improver has been reduced. In addition, the use of a special poly-methacrylate in the formulation has substantially improved the oil film thickness. The results of laboratory tests conducted with actual manual transmissions confirmed that the new oil provides performance equal to that of current oil. There was no sign that the reduction of viscosity caused any decline in extreme pressure performance or anti-pitting performance. In tests conducted with actual transmissions, it was found that lower viscosity had the effect of reducing friction by 10-20% in an actual operating temperature range of -10° to 80°C. Evaluations conducted with actual transmissions also showed that the new oil improved low-temperature shiftability by 40% at -5°C.
Matsuzaki, Kentaro, Yamamoto, Toyokazu, Abe, Saburo, Sagawa, Takumaru, Nakamura, Kiyotaka
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