Abstract: A charging system for a hybrid vehicle comprises an internal combustion engine, an electric motor generator coupled to the internal combustion engine and operable to be driven as a generator to produce a charging voltage and a battery coupled to the electric motor generator and configured to receive a charge voltage. The charging system further comprises an engine control computer coupled to the internal combustion engine, the electric motor generator and the battery. The engine control computer is configured to determine a threshold for a charging specific fuel consumption (CSFC), calculate an instantaneous CSFC; and initiate active charging of the battery if the instantaneous CSFC is less than or equal to the threshold CSFC.

Abstract: A fuel vapor canister is purged by admitting fuel vapor from the canister to the vehicle engine under control of a solenoid valve, the duty cycle of the valve being controlled to optimize the purge rate. Closed loop fuel correction and block learn fuel correction factors developed by the fuel control system are used to update a learned purge duty cycle which is stored in a keep-alive memory.

Abstract: Potentially damaging operation of a viscous converter clutch (VCC) is detected in relation to the slippage thereacross. The slippage is compared with a reference slip value indicative of excessive VCC slippage to develop a net overslip indicator. The value of the net overslip indicator changes in the direction of a first limit value so long as the detected slip is at least as great as the reference slip, and in the direction of a second limit value so long as the detected slip is less than the reference slip. When the net overslip indicator reaches the first limit value, the friction clutch is disengaged to release the VCC. According to a first embodiment, the transmission fluid temperature at the time of such deactivation is measured and stored, and the VCC is reactivated when transmission fluid temperature falls below the stored temperature, assuming other criteria for activation are also met.