Common rail system for injection IC engine has the high pressure fuel pump lubricated by fuel tapped off the low pressure feed and returned into the fuel tank

摘要

A common rail fuel feed system for an IC engine has fuel pumped from the fuel tank (1) by a low pressure pump (3). The low pressure feed delivers fuel to the high pressure pump (6) via a non return valve (11) which opens at a preset pressure. Some of the low pressure fuel is returned to the fuel tank via a control valve (8). The return flow fuel also lubricates the high pressure fuel pump. No separate return line is required for fuel leaks.