Electric Oil Pump (EOP) Description and Operation

Description

This transaxle has a standard mechanical oil pump (MOP) connected to the input shaft to generate oil pressure when the input shaft rotates. As a hybrid, this transaxle also has an electric oil pump (EOP). Because the hybrid has an Auto-Stop function that starts and stops the engine as needed, the Auto-Stop function prevents the mechanical oil pump (MOP) from operating and generating sufficient pressure for the transaxle to operate. When the vehicle stops with the engine off, the mechanical oil pump (MOP) cannot generate sufficient oil pressure during initial start-up (less than 5 km/h) or during low-speed driving. For these reasons, the electric oil pump (EOP) takes over this role as an auxiliary device capable of generating the required oil pressure when the vehicle is stopped or moving at low speed. The electric oil pump (EOP) supplies oil pressure not only to the Under Drive Brake (UD/B), but also to the Engine Clutch (E/C).

• During low-speed driving or Auto-Stop of the engine, it supplies oil pressure to the Under Drive Brake (UD/B) of the automatic transaxle.
• It supplies oil pressure to the Engine Clutch (E/C) when engine power is required.

  

EOP Operation

Start-Up and Slow Driving (Low Speed)	Item	Operation	Description
	HSG	Stopped	- Vehicle is driven by the electric motor (EV mode) > The EOP operates to supply hydraulic pressure to 1st gear in the automatic transaxle during vehicle start-up.
	Motor	Rotation
	Engine	Stopped
	E Clutch Electronic	Disconnect
	EOP	Rotation
	B	1st Gear
Auto Stop	Item	Operation	Description
	HSG	Stopped	- The EOP operates to supply hydraulic pressure (to be ready for vehicle start-up) > You may hear the EOP operating noise
	Motor	Stopped
	Engine	Stopped
	E Clutch Electronic	Disconnect
	EOP	Rotation
	B	D Range