Today, the contribution of the transportation sector on greenhouse gases is evident. The fast consumption of fossil fuels and its impact on the environment have given a strong impetus to the development of vehicles with better fuel economy. Hybrid electric vehicles fit into this context with different targets, starting from the reduction of emissions and fuel consumption, but also for performance and comfort enhancement. Lamborghini has recently invested in the development of a hybrid super sport car, due to performance and comfort reasons. Aventador series gearbox is an Independent Shift Rod gearbox with a single clutch and during gear shifts, as all the single clutch gearbox do, it generates a torque gap. To avoid the additional weight of a Dual Clutch Transmission, a 48V Electric Motor has been connected to the wheels, in a P3 configuration, to fill the torque gap, and to habilitate regenerative braking and electric boost functions. This paper discusses the usage of a control

Franceschi, Alessandro, Cavina, Nicolo, Parenti, Riccardo, Reggiani, Maurizio, Corti, Enrico

Dynamics and Control of Gearshifts in Wet-Type Dual Clutch Transmission for BEVs

2020-01-076704/14/2020

The dual clutch transmission is one of the possible choices for electric vehicle drivelines. The basic principle and control mode of shifting of wet dual clutch transmission are introduced, and the dynamic process of shifting of wet double clutch transmission is studied. Combined with the dynamic model of the wet clutch engagement process, the difference between the dynamic characteristics of the dual clutch transmission modeling using the Coulomb friction model and the dual-clutch transmission model using the average flow model and the micro-convex contact theory is analyzed. The shift control strategy of the dual clutch transmission proposes a correction method to improve the shifting smoothness. Studies have shown that the torque response of the wet clutch has significant hysteresis, and the improved control algorithm can significantly improve the shifting smoothness of the wet dual clutch transmission. Based on the dynamic model of the wet clutch, the torque interruption of the

Lou, Zhenxiong, Duan, Yupeng, Zhang, Yunqing

System Evaluation Method for Two Planetary Gears Hybrid Powertrain under Gray Relational Analysis Based on Fuzzy AHP and Entropy Weight Method

2020-01-043004/14/2020

Millions of configurations of power-split hybrid powertrain can be generated due to variation in number of planetary-gear sets (PG), difference in number, type and installation location of shift actuators (clutches or brakes), and difference in connection positions of power components. Considering the large number of configurations, complex structures and control modes, it is vital to construct an appropriate multi-index system evaluation method, which directly affects the requirement fulfillment, the time and cost of 2-PG system configuration design. Considering one-sidedness (dynamics and economic performance), simplicity (linear combination of indicators) and subjectivity (relying on expert experience) of previous system evaluation method of 2-PG system design, a more systematic evaluation method is proposed in this paper. The proposed evaluation system consists of five aspects, involving dynamic, economy, comfort, reliability and cost, and more than 20 indexes. To reduce the

Gu, Jiading, Zhao, Zhiguo, Chen, Yi

Internal Model Control during Mode Transition Subject to Time Delay for Hybrid Electric Vehicles

2020-01-096104/14/2020

With the rapid development of series-parallel hybrid electric vehicles (SPHEVs), mode transition from pure electrical drive to hybrid drive has attracted considerable attention. The presence of time delay due to response capacity of actuators and signal transmission of communication may cause decrease of speed tracking accuracy, even instable dynamics. Consequently, drivability of the SPHEV is unacceptable, and durability of the components is reduced. So far, plenty of control strategies have been proposed for mode transition, however, no previous research has been reported to deal with the time delay during mode transition. In this paper, a dynamic model with time delay of hybrid electric system is established. Next, a mode transition time-delay controller is proposed based on a two degree of freedom internal model controller (2-DOF-IMC). Considering the control plant has three inputs (the engine output torque, clutch transmitted torque and traction motor output torque) and two

Miao, Dongxiao, Chen, Li, Yi, Ping

Two-Speed Transmission Gear Shift Process Analysis and Optimization Using Genetic Algorithm

08-09-01-000101/16/2020

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

Cao, Zhan, Yang, Jiansen, Wang, Xinyu

Automatic Transmissions - Schematic Diagrams

J647_201911 (Current)11/19/2019

The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.

Automatic Transmission and Transaxle Committee

Modelling and Control of a Novel Clutchless Multiple-Speed Transmission for Electric Vehicles

2019-24-006309/09/2019

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

Malafronte, Ludovica, Grandone, Mauro, Lega, Alberto, Pennese, Michele, Pianese, Cesare

Dual Clutch Transmission Vibrations during Gear Shift: A Simulation-Based Approach for Clunking Noise Assessment

2019-01-155306/05/2019

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

Galvagno, Enrico, Dimauro, Luca, Mari, Gianluca, Velardocchia, Mauro, Vella, Angelo Domenico

Modeling and Validation of a Transmission E-Pump for Application in Hybrid Vehicles

2019-01-034904/02/2019

The Electric Pump (E-Pump) is a critical component in the hybrid transmission system. The E-Pump provides flow to maintain a stable line pressure when the engine is in an off state. The main applications of the E-Pump are Park Pawl engagement and disengagement, engine start-stop operation and shadow shifting. A Systems Engineering Approach was followed to develop a medium fidelity plant model for the E-Pump. The developed model was initially tested and validated in the Model in-the loop (MIL) environment. After initial validation, the model was integrated into the overall vehicle model which was then tested on the Software in-the loop (SIL) and Hardware in-the loop (HIL) environments. The model was validated across different platforms and several operating conditions. The basic applications of the E-Pump such as park pawl actuation, engine starting and shadow shifting were validated. The model was later validated using the data, which was acquired on a prototype vehicle run on a

Kannan, Kaushik, Veeramurthy, Gangarjun, Yamazaki, Mark

Coordinated Mode Transition Control for a Novel Compound Power-Split Hybrid Electric Vehicle

2019-01-130604/02/2019

Because of the direct connection between the compound power split hybrid transmission (CPSHT) and the engine in hybrid electric vehicle (HEV), engine ripple torque (ERT) can lead to obvious jerks when the mode transition from electric driving mode to hybrid driving mode occurs. In order to enhance the riding comfort, two additional wet clutches are mounted in this novel CPSHT and the relevant coordinated control strategy is developed. Firstly, after the description of the mechanical and hydraulic parts of the novel CPSHT, the dynamic plant model including driveline model, engine ripple torque and clutch torque is deduced. Secondly, the mode transition process in the original and current designs are compared and analyzed with the equivalent level diagram and the encountered problems are stated. Thirdly, a coordinated control strategy is designed to determine the target motor torque, clutch torque, engine torque, and the moment of fuel injection based on the second-order sliding mode

Shen, Dengfeng, Guehmann, Clemens, Zhang, Tong

Theoretical and Experimental Investigation on Power Loss of Vehicle Transmission Synchronizers with Spray Lubrication

2019-01-002801/15/2019

Besides optimal engine systems, high-efficiency vehicle transmissions are generally also required to improve fuel economy in automotive applications. For the energy loss analysis in transmissions, most research focused on the major mechanical components, such as gears, bearings and seals, while the other mechanical losses, like synchronizer losses, were usually not considered. With increasing number of synchronizers in modern transmissions, a recent study indicates that the power loss analysis of synchronizers should also be developed and appended for a more accurate investigation on overall power losses in transmissions. The function of synchronizer is to equalize the different rotational speeds of shafts and gear wheels by frictional torques, for which the synchronizer must be cooled and lubricated in order to enhance the service life. With the supplement of lubricants, fluid friction is generated due to the differential speed, when the synchronizer is in neutral position. This fluid

Liu, Zhihong, Shen, Ye, Rinderknecht, Stephan

Prediction of Oil Flow inside Tractor Transmission for Splash Type Lubrication

2019-26-008201/09/2019

This study introduces a method to examine the flow path of the lubricant inside a transmission housing of a tractor. A typical gearbox has several loads bearing elements which are in relative sliding motion to each other which causes heat to be released. The major sources of friction as well as heat are the meshing teeth between gears (sun/planet, planet/ring & power/range drive gear), thrust washers, thrust bearings and needle roller bearings. The churning of oil performs the vital function of both lubricating these sliding interfaces and cooling these sources of heat, thereby preventing failure of the gearbox. In this paper, we have applied VOF multiphase flow model and sliding meshing to simulate the fluid flow during splashed lubrication within a mating gear box. Lubrication oil dynamics and oil surface interaction with the air is modeled using VOF multiphase approach. The gear motion is imparted through sliding mesh technique, it automatically reconfigures the mesh for the space

Santra, Tanmay Sushant, Raju, Kumar, Deshmukh, Rahul, Gopinathan, Nagarajan, Paradarami, Udaya, Agrawal, Ayush

The Influence of Friction Modifiers in Fully Formulated Motorcycle Engine Oils

2018-32-002410/30/2018

Globally, emissions legislation placed on motorcycles is becoming ever more stringent [1]. One way of meeting these new regulations is to use friction modifiers (FMs) in the engine oil to reduce frictional losses in the engine. This is, however, complicated by the fact that many motorcycles use a common oil sump for both the engine and a lubricated clutch. It is often the case that if a FM reduces friction in a steel/steel contact it will also reduce friction in a steel/friction material contact. Therefore, it is usually viewed that there will be a necessary compromise between maximizing engine efficiency and maintaining efficient clutch performance. In this paper we examine the effect of a range of organic FMs on commercial fully formulated motorcycle engine oils (MCOs) using benchtop tribotests and full-scale rig tests (SAE #2 clutch test machine). The results show that by careful selection of appropriate FM chemistry it is possible to reduce steel/steel friction whilst maintaining

Gillespie, David, Moody, Gareth, Viadas, Aitziber

A Review of the State of the Art of Electric Traction Motors Cooling Techniques

2018-01-0057

04/03/2018

This paper provides a review on state-of-art modern cooling systems employed for thermal cooling of electric motors for vehicle applications. In recent years, the pursue of a more sustainable and ecofriendly mobility has pushed the research towards the development of electric vehicle powertrain systems. Besides the evident advantages of the adoption of electric traction systems in terms of pollution and efficiency, the need of an effective cooling system for the electric machine components gained more and more importance in order to maintain high efficiency and ensure high durability. In fact, it is known that high temperatures can be harmful for the electric motor: besides the evident damages for mechanical parts, the influence on the permanent magnet properties is not negligible [1] [2]. In this fast-evolving environment, different solutions for the thermal problem have been researched and adopted, each one with its own pros and cons. Those who face the development of a PM machine

Carriero, Alberto, Locatelli, Matteo, Ramakrishnan, Kesavan, Mastinu, Gianpiero, Gobbi, Massimiliano