Abstract: A control strategy for a hybrid electric vehicle (HEV) to meet driver expectation for hill holding or creep capability found in conventional automobiles with an automatic transmission. The strategy is activated when the PRNDL is in drive or low-drive position and no accelerator applied. Alternatively, the strategy can also require no brake being applied as well. The strategy can use the traction motor, generator motor or engine to achieve creep or hill holding. The engine is used when the traction motor temperature exceeds a predefined value or the engine is already running. If the engine is not running, the strategy can determine when to start it and regulate the amount of engine torque needed to hold the vehicle on the hill using the generator motor. The strategy maintains efficient engine usage and minimizes battery usage and loss.

Abstract: A diagnostic system for controlling an engine low oil pressure indicator in a hybrid electric vehicle includes a powertrain having an engine and an electric traction motor, an oil pressure sensor/sending unit mechanically connected to the engine, an engine speed sensor/sending unit mechanically connected to the engine, a controller having connections to the oil pressure sensor and engine speed sensor, a low oil pressure indicator electrically connected to the controller, a mode selector having modes for “off” and “run/start”, the controller being configured to prevent activation of the low oil pressure indicator when the mode selector is in the “run/start” mode and the engine is not running.

Abstract: The present invention provides a method and system for determining “engine on” status in a Hybrid Electric Vehicle. A controller determines the engine is necessary and then checks the current “engine on” status. If the engine is not currently running, the controller proceeds to start the engine by commanding the generator to spin or “motor” the engine. The controller then starts fuel flow and spark within the engine to create combustion. A measuring device is then used to determine the crankshaft speed. The controller receives this measurement and determines whether the measured variations in crankshaft speed exceed a calibratable threshold. If the calibratable threshold is exceeded, combustion is determined to be occurring and the engine is on. The controller then turns on the “engine on” status flag.