Injection system for internal combustion engine enables use of pre-delivery pump with low output pressure

摘要

The injection system has a pre-delivery pump (1) for delivering fuel from a fuel tank (4), a downstream high pressure pump (6) with at least one inlet valve that opens when a predefined difference pressure is exceeded and a branched flushing line (13) connected to the high pressure pump for flushing it with fuel, and a difference pressure valve (16) in the flushing line that only allows the fuel flow in the flushing line when an opening difference pressure is exceeded to accelerate the pressure build-up during engine starting. The opening difference pressure of the valve in the flushing line is higher than the inlet valve opening pressure, which is lower than or equal to 0.9 bar, and is lower than 2 bar.