Abstract: A mean vehicle speed Va and a mean variation .DELTA.Va are factors reflecting a current driving condition and an expected driving condition of a vehicle, which relate to a charge-discharge amount of a battery. A target state SOC* of the battery is calculated from the mean vehicle speed Va and the mean variation .DELTA.Va. The charge-discharge amount of the battery increases with an increase in mean vehicle speed Va and mean variation .DELTA.Va. The lower charging state of the battery results in the higher charge-discharge efficiency. The structure of the present invention sets the target state SOC* of the battery and controls the actual state of the battery to the target state SOC*, thereby enhancing the charge-discharge efficiency of the battery and ensuring a sufficient supply of electric power required for driving the vehicle.

Abstract: An electrical distribution system for a motor vehicle comprises an engine, an electrically-conductive structural portion of the vehicle and a battery having a positive terminal and a negative terminal. The system also includes a starter motor having an electrical current return electrically coupled to the engine and an electrical generator having an electrical current return electrically coupled to the engine. Also, the system comprises an electrical current return path from the structural portion to the engine and an electrical current return conductor electrically and mechanically coupled between the engine and the structural portion. In addition, the system contains a capacitor coupled in series with the electrical current return conductor. In a variation of the disclosed system, the connections to the structural portion of the vehicle are made to the body and/or chassis of the vehicle. Systems built to according to the present invention have been demonstrated to have very advantageous properties.

Abstract: A system and method for controlling operation of a diesel electric traction vehicle of the type including a synchronous generator driven by a diesel engine for producing alternating current (AC) electric power, the AC electric power being converted to direct current (DC) electric power and transferred over a DC link to a plurality of DC to AC inverters, and each of the inverters being coupled to transfer controlled frequency power to at least one AC electric traction motor coupled in driving relationship to at least one wheel-axle set of the vehicle. A computer-based control system controls operation of the engine, generator and inverters in response to a power command signal. The control system computes power supplied by the generator from calculated torque developed by the AC traction motors and electric power losses in the inverters and other circuit elements coupling power from the generator to the motors.

Abstract: A hybrid drive system including an engine and an electric motor at least one of which is operated as drive power source to drive a motor vehicle in a selected one of different operation modes. The system is adapted to prevent concurrent operations to change the operation mode and the speed ratio of a power transmitting device or the ratio of torque distribution to front and rear drive wheels, or concurrent operations to change the operation mode and switch the power transmitting device from a non-drive state to a drive state, for avoiding a shock due to a torque variation which would arise from the concurrent operations. The system is alternatively adapted to cut a power transfer from the drive power source to the power transmitting device, or hold the output of the drive power source substantially constant, when the power transmitting device is switched from the non-drive state to the drive state.