Patent ID: 6098733
Filing Date: 2000-08-08
Classification: B60K,B60L,B60W,Y02T,Y10S

Abstract:
A hybrid drive system for a motor vehicle, comprising:an engine operated as a first drive power source by combustion of a fuel;an electric energy storage device which is charged with an electric energy by operation of said engine;an electric motor operated as a second drive power source by the electric energy stored in said electric energy storage device; anda controller for selecting a low-load drive mode in which only said electric motor is operated to drive the vehicle, when a load as represented by a running condition of the vehicle and acting on the hybrid drive system is in a predetermined low-load range, and a high-load drive mode in which at least said engine is operated to drive the vehicle, when said load is in a predetermined high-load range in which said load acting on the hybrid drive system is higher than that in said predetermined low-load range, said running condition being represented by an amount of power currently required by an operator of the vehicle to drive the vehicle,and wherein said controller includes;emergency drive control means operated in the event of a failure of one of said engine and said electric motor as said first and second drive power sources, for operating the other of said first and second drive power sources to drive said motor vehicle; andrange changing means for changing one of said predetermined low-load and high-load ranges which corresponds to said other of said first and second drive power sources, when said other of said first and second drive power sources is operated by said emergency drive control means,said range changing means comprising upper limit changing means for narrowing said predetermined low-load range by reducing an upper limit of said low-load range, when said electric motor is operated as said other drive power source by said emergency drive control means in the event of a failure of said engine, so as to limit an output power produced by said electric motor to a value corresponding to the reduced upper limit of said low-load range, so that an amount of consumption of the electric energy by said electric motor is reduced to increase a distance of running of the motor vehicle by operation of said electric motor by the electric energy stored in said electric energy storage device.