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Training / Education

Fundamentals of Modern Vehicle Transmissions

2021-06-14
Starting with a look at the transmission's primary function -- to couple the engine to the driveline and provide torque ratios between the two -- this updated and expanded seminar covers the latest transmission systems designed to achieve the most efficient engine operation. Current designs, the components and sub-systems used, their functional modes, how they operate, and the inter-relationships will be discussed. A manual transmission display will be used to explain ratios and how they function within the driveline.
Training / Education

Analysis and Design of Hybrid Transmission System

2021-05-13
There appears to be a significant gap between the Chinese and international hybrid technologies in terms of vehicle fuel consumption, system integration and cost control. This course has been designed to increase an engineers’ knowledge of hybrid transmission development, hybrid system design, and hybrid vehicle powertrain integration. The course focuses on energy efficiency in electric vehicles (EV) and HEV fuel economy while maintaining and improving engineering for optimal power and performance, cost control, and occupant comfort.
Technical Paper

Design of Baja SAE Gearbox for Optimal Performance and Minimum Weight

2020-11-30
2020-32-2311
Baja SAE is an intercollegiate competition where teams design and build a single-seat off-road vehicle that is powered by a small 10 HP Briggs & Stratton engine. Due to this power constraint, it is crucial to optimize the vehicle's weight and performance. The purpose of this paper is to demonstrate the process of simulating, designing, manufacturing, and testing the gearbox of the vehicle. The design process began by creating a vehicle dynamics simulation, which included engine performance, CVT Shifting, tire slipping, vehicle mass, rotational inertia, air drag, rolling resistance, weight shift, and drivetrain efficiency. These calculations predicted acceleration times, top speed, and optimal gear ratio. An often-neglected parameter that was analyzed was the rotational inertia in the drivetrain system. The results showed the effective mass of the vehicle increased 12% above the weight of the vehicle, primarily due to the weight and size of the CVT primary pulley.
Technical Paper

An Electric-Drive to Parallel-Drive Mode Transition Control Strategy for a P2 Hybrid Powertrain

2020-10-22
2020-01-5099
Hybrid powertrains have become many original equipment manufacturers (OEMs)’ choice to meet ever-stringent fuel consumption regulations. A P2 powertrain technology is widely adopted by automotive OEMs to reuse existing engines and transmission production capacity and reduce investment. A standalone P2 module of an integrated e-motor with an engine decoupling wet clutch is developed and applied in a transverse-mounted P2 hybrid powertrain system. A P2 hybrid powertrain controller has been developed to test and validate the P2 module and control strategy. This P2 powertrain system with a decoupling clutch capable of slipping control enables the vehicle launch or low-speed drive in engine direct-drive mode. A control algorithm that controls the clutch slipping to transmit the desired cranking torque from P2 e-motor to fast-start the engine during the drive mode change from Electric drive to Parallel drive has been developed and validated.
Standard

Adaptive Cruise Control (ACC) Operating Characteristics and User Interface

2020-10-12
WIP
J2399
Adaptive cruise control (ACC) is an enhancement of conventional cruise control systems that allows the ACC-equipped vehicle to follow a forward vehicle at a pre-selected time gap, up to a driver selected speed, by controlling the engine, power train, and/or service brakes. This SAE Standard focuses on specifying the minimum requirements for ACC system operating characteristics and elements of the user interface. This document applies to original equipment and aftermarket ACC systems for passenger vehicles (including motorcycles). This document does not apply to heavy vehicles (GVWR > 10,000 lbs. or 4,536 kg). Furthermore, this document does not address other variations on ACC, such as “stop & go” ACC, that can bring the equipped vehicle to a stop and reaccelerate. Future revisions of this document should consider enhanced versions of ACC, as well as the integration of ACC with Forward Vehicle Collision Warning Systems (FVCWS).
Technical Paper

Analytical Rotordynamic Study of a High-Speed Gear Transmission System for Race Applications

2020-09-30
2020-01-1502
In motorsport power transmission systems, high-speed operation can be associated with significant rotordynamic effects. Changes in the natural frequencies of lateral (bending) vibrational modes as a function of spin speed are brought about by gyroscopic action linked to flexible shafts and mounted gear components. In the investigation of high-speed systems, it is important that these effects are included in the analysis in order to accurately predict the critical speeds encountered due to the action of the gear mesh and other sources of excitation. The rotordynamic behaviour of the system can interact with crucial physical parameters of the transmission, such as the stiffnesses of the gear mesh and rolling element-to-raceway contact in the bearings. In addition, the presence of the gear mesh acts to couple the lateral and torsional vibration modes of a dual-shaft transmission through which a torque flows.
Technical Paper

In-Depth PHEV Driveline Torsional Vibration Induced Vehicle NVH Response Study by Integrated CAE/Testing Methodology

2020-09-30
2020-01-1507
In this paper, a 1-D refined driveline model in AMESIM was built up, for a P2.5 topology PHEV. The model includes detailed engine, damper, dual clutch transmission, differential, motor, half-shaft, wheel, body, suspension, powertrain mounting and powertrain rigid body, The objective of the simulation is to predict torsional vibration induced vehicle NVH response under different driving scenarios. Firstly, the torsional vibration modes were predicted, and the critical modes were identified. This enabled a good understanding of modal alignment, identification of countermeasures and provide feedback to other engineering teams in the early stages of vehicle development.
Technical Paper

On Predicting Automotive Clutch Torsional Vibrations

2020-09-30
2020-01-1508
Automotive clutches are prone to rigid body torsional vibrations during engagement, a phenomenon referred to as take-up judder. This is also accompanied by fore and aft vehicle motions. Aside from driver behaviour in sudden release of clutch pedal (resulting in loss of clamp load), and type and state of friction lining material, the interfacial slip speed and contact temperature can significantly affect the propensity of clutch to judder. The ability to accurately predict the judder phenomenon relies significantly on the determination of operational frictional characteristics of the clutch lining material. This is dependent upon contact pressure, temperature and interfacial slip speed. The current study investigates the ability to predict clutch judder vibration with the degree of complexity of the torsional dynamics model. For this purpose, the results from a four and nine degrees of freedom dynamics models are compared and discussed.
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