Modern cars have lots of electric stuff like fans etc.The oil pump does not need to much energy to spin so making it electric would not be a nightmare on a car with an orthodox electrical system .The oil pressure could be regulated be PWM comtrol of the electric oil pump motor speed .My question is would it increase engine life if it is primed up before cranking ?Is it true that stop start has a big effect on car engine life ?
It only seems like driving an oil pump is easy, in reality driving an oil pump is very hard. The biggest issue is the viscosity of the oil especially when it's cold.
The second issue is, the oil pump is the most critical component of the engine. A bad oil pump leads to engine failure 100% of the time. A bad fan or a bad electric water pump or a bad fuel pump don't lead to immediate engine failure. A mechanically driven oil pump is guaranteed to spin when the engine is spinning.
The ware effects of dry engine starts are exaggerated for daily drivers. Overnight the critical components retain enough oil to allow the engine to build oil pressure before engine damage occurs. When engines sit for weeks at a time a shortening of life from a dry start may occur but it is hard to quantify.
I think a good compromise might be to have an electric pump for priming but a mechanical pump for general engine operation.