Fuel injection system for IC engine has surplus fuel from high pressure rail fed back into high pressure pump via a separate pump

摘要

A fuel injection system for an IC engine has a high pressure fuel pump (5) feeding a common rail (3). Surplus and leaked fuel, from the high pressure circuit, is returned to the input of the high pressure pump using a separate pump (12) and non return valve (13). This increases the pumping efficiency of the system and enables a smaller delivery pump (2) to be fitted into the fuel tank. The separate pump can be driven mechanically or electrically and draws fuel from the return fuel line. Any surplus fuel is returned to the fuel tank in the normal way.