Ford Research Laboratory is currently developing many technologies to enable future production of hybridelectric vehicles. One promising technology is the Modular Hybrid Transmission (MHT) system. This system has significant challenges of delivering substantial fuel economy benefits while maintaining acceptable drivability. To achieve substantial fuel economy improvements it is necessary to shut down the engine when its power output is not needed. Under normal operating conditions, the engine will shut down below 88 kph, anytime the driver fully releases the accelerator pedal. The engine will remain off until the driver commands a certain power level and then the engine will restart. The drivability problems occur when the driver's desire to accelerate changes quickly and the engine is still shut down. This situation can occur both from rest and while already moving. Launching a vehicle, without a torque converter, is a difficult challenge for a 4-speed automatic transmission. Given a particular induction motor torque capacity, the amount of 'electric only' drive capability the vehicle will have, is to a large part determined by the magnitude of torque required to start the engine turning. Once the MHT system is in its 'electric only' drive mode, to start the engine turning, without disturbing the torque already driving the wheels, only the induction motor torque capacity beyond what is required to start the engine turning can be made available. Since we purposely stop the engine while driving we end up needing to start the engine frequently and under various conditions. In the MHT system discussed in the paper, the torque converter has been replaced with a 40-kilowatt electric induction machine, which is coupled to a 300 volt - 3.6 Ah Lithium-Ion battery in a 1450 kg vehicle. Also, an added wet clutch system allows the engine to be disconnected from the electric machine enabling 'electric only' driving.
Challenges of engine starts and drivability in a parallel hybrid-electric system
Herausforderungen von Motorstart und Steuerbarkeit in einem parallelen hybrid-elektrischen System
2004
10 Seiten, 17 Bilder, 8 Quellen
Conference paper
English
Challenges of Engine Starts and Drivability in a Parallel Hybrid-Electric System
British Library Conference Proceedings | 2004
|Challenges of Engine Starts and Drivability in a Parallel Hybrid-Electric System
SAE Technical Papers | 2004
|Challenges of engine starts and drivability in a parallel hybrid-electric system
Automotive engineering | 2004
|Challenges of Engine Starts and Drivabilitv in a Parallel Hybrid-Electric System
British Library Conference Proceedings | 2004
|