US Patent 7891341 Control device for internal combustion engine

A fuel supply system includes a first non-return valve for a low-pressure delivery connection pipe and a second non-return valve for a pump supply pipe. The former non-return pipe does not allow fuel to flow from the low-pressure delivery pipe to the low-pressure supply pipe. The second non-return valve does not allow fuel to flow from pump supply pipe to the low-pressure supply pipe. Upon determining that air purging is necessary, an engine ECU operates a feed pump for approximately one second and then opens, for dummy injection, an in-cylinder injector and an intake manifold injector.