Primary steering enabler during engine failure

摘要

A system and method are provided for maintaining hydraulic steering for a machine during engine out or engine lugging conditions. The machine includes a torque-controlled transmission driven by an engine, the engine further being linked to a hydraulic steering pump that provides hydraulic power to a steering actuator. The machine may be, for example, a wheel loader or an off highway truck. The system and method include detecting an undesirable reduction of engine speed while the machine is travelling, and responsively reducing the transmission power to maintain the engine speed at a desired level to power the hydraulic steering pump. When the reduced requested transmission power reaches zero, a power reversal through the transmission is commanded to maintain the engine speed at the desired level to power the hydraulic steering pump.

主权项

1. A method of providing steering in a machine having a torque-controlled transmission driven by an engine, the engine further being linked to a hydraulic steering pump that provides hydraulic power to a steering actuator, the method comprising:
detecting an undesirable reduction of engine speed while the machine is travelling at a speed pursuant to a torque command to the transmission; reducing the transmission power via the torque command to maintain the engine speed at a desired level to power the hydraulic steering pump; and when the reduced transmission power reaches zero, commanding a power reversal through the transmission to maintain the engine speed at the desired level to power the hydraulic steering pump.