Hybrid electric vehicles (HEV) come with some curious challenges compared to traditional internal combustion engines (ICE).
One common concern is that the start-stop engine mechanism can lead to increased engine wear due to a potential lack of oil lubrication. A new electric oil pump being developed may offer a solution.
In HEVs, start-stop systems will shut down the ICE when the vehicle is idling or coasting, and restart the engine when the driver hits the gas. The advantage of this is reduced fuel consumption and reduced CO2 emissions.
Unfortunately, the lubrication oil pump and air conditioning systems often shut down with the engine.
The lubrication problem is exacerbated in HEVs when switching between the electric motor and ICE engine systems. The concern is a lack of oil lubrication due to zero pump pressure when the vehicle runs on the electric motor.
Because there is no power delay on restart, this can mean high-speed rotary movement will begin before the hydrodynamic film is distributed through the engine. This will cause metal-to-metal contact and wear.
However, the new electric oil pump and electric air compressor in development by Brose will ensure these systems continue to function whether the vehicle is running on the electric motor or the standard engine.
This will help to avoid wear on the engine and bearings during start-stop and coasting driving modes when the ICE is not running.
Effectively, the oil pump is designed to maintain the oil pressure during these driving modes, without affecting handling or vehicle engine restart time.
The system is comprised of an electrically-commuted motor, an electronic control unit (ECU) and a hydraulic pump for a power range of 30 to 50 watts. It is also lighter than component systems, and available with either ferrite or rare-earth magnets, depending on the HEV’s requirements.
Brose will also be releasing an electric air compressor to run the car’s air conditioning while in electric motor operation.
Brose intends to begin series production on the oil pump in 2018, to create options for efficiency in both conventional drives and in electric and hybrid vehicles.
For more information on Brose and their oil pump development, check out their website.