Electric hydraulic PAS pumps

[murpia]

A lot of cars now use electric pumps to power conventional hydraulic PAS systems. Feel can be made speed sensitive, less parasitic losses on the engine, etc.

Is there a good primer anywhere on the details of the technology?

Questions that spring to mind are:

Who are the usual suppliers?
What kind of motors, brushed or brushless DC?
Is there a separate PAS control module?
Or a separate power module (control in the engine ECU)?
What new sensors are in use (pump pressure, pump speed, rack pressure etc.)?

Thanks, Ian

 

[Porsche356supersport]

Hi Ian,

I'm involved in this area because we supply a motor positon sensor for an EPAS motor application. I hope I can provide you some assistance. For any specific questions please PM me.

Who are the usual suppliers?
Globe Motors, EBM Papst, Denso, Brose, AMK, Mitsubishi Electric, Mark IV, ASMO, NIDEC, IXETIC and AISIN.

What kind of motors, brushed or brushless DC?
In the majority of cases BLDC motors are used.

Is there a separate PAS control module?
Typically there is a steering ECU which is provided the signal from the BLDC motor position sensor.

What new sensors are in use (pump pressure, pump speed, rack pressure etc.)?
Sensors are essentially used for motor commutation. In the past three-phase hall effect arrays were used. These arrays have the problem that at high speeds they miss phases which effects the commutation of the motor. Our AMR based sensor is used to measure speed, direction of rotation and position. Another possibility is to use a resolver to measure the same characterisitics of the motor. The signal is sent to the ECU and contrasted with the signal from the steering angle and torque sensor to confirm functionality.

Do you mind if I ask what your interest is in this area?

Best Regards

 

[murpia]

Our interest is in replacing an engine driven hydraulic pump with an electric powered pump. Not for power steering but for a transmission application.

We've spec'd an industrial motor with a separate controller for the prototype. But in the longer term we'd need a supplier of an automotive motor with integrated controller that can survive in the engine compartment.

Electric power steering pump motors look ideal, although the pump would not be the same.

Thanks, Ian

 

[Porsche356supersport]

Hi Ian, I don't represent any of these companies so this should not be considered as a promotion. However the following companies should be able to help you Ixetic, Nidec
and Brose. PM me if you want specific contacts at these companies. Best Regards