Apparatus and method for operating a hybrid drive system during an extended braking condition

摘要

A hybrid drive system for use in a drive train assembly of a vehicle includes a control apparatus that operates the hybrid drive system in either a normal energy recovery mode in response to a braking request or an extended braking mode in response to an extended braking request. In the normal energy recovery mode, fluid is pumped to an accumulator, which consumes kinetic energy of the vehicle and causes deceleration of the vehicle. In the extended braking mode, fluid is pumped through a pressure relief valve containing a restriction, which consumes the kinetic energy of the vehicle and causes deceleration of the vehicle. If the temperature of the fluid being pumped through the pressure relief valve exceeds a predetermined value, fluid is alternatively pumped through a pump/motor operating in a motoring mode, which consumes the kinetic energy of the vehicle and causes deceleration the vehicle.

主权项

1. A system comprising:
a hybrid drive system; and a control apparatus that operates the hybrid drive system in a normal energy recovery mode in response to a braking request and in an extended braking mode in response to an extended braking request; wherein deceleration of the hybrid drive system is accomplished in both the normal energy recovery mode and in the extended braking mode without the use of foundation brakes; when the hybrid drive system is operated in the normal energy recovery mode, fluid is pumped to an accumulator to consume kinetic energy; and when the hybrid drive system is operated in extended braking mode, fluid is pumped through either (1) a pressure relief valve containing a restriction or (2) a pump/motor operating in a motoring mode to consume kinetic energy.