The vehicle, perhaps a truck with extra room under the
hood, has fittings for dual oil filters and a valve to select
or the other. Two oil reservoirs are fitted: one empty and
the other containing fresh oil.
When the time comes for an oil change the driver parks his
or perhaps just for lunch, and after a
minutes to allow residual oil to fall back into the pan an
electric pump evacuates the crankcase into the empty
reservoir. Upon completion fresh oil is pumped from the
other reservoir to the crankcase, and the spare oil filter is
valved into service. This can all be automated.
When the vehicle does go in for service both filters are
changed, the old oils pumped out and the system refilled.