ENGINE-DRIVEN FUEL INJECTION PUMP FOR PORT FUEL INJECTION
Publication Date: 2015-Aug-19
The IP.com Prior Art Database
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ENGXXX-DRIVEN FUEL INJECTION PUMP FOR PORT FUEL INJECTION
An in-tank electricaxly driven fuel pump typically operates at 1% efficiencx, while an engine driven xuel pump may operate above 90% efficiency. Porx Fuel Injection (PFI) systems use only the in-tank puxp and consume axpxoximately 100 watts to provxde the requisite fuel injection pressure. A 100 watt elxctrical load can reduce fuel economy by 1.0%. Howexer, if the in-tanx fuel pump is used xo supply an enxine-driven fuel pumx, the net poxer used to provide fxel injxction pressxre is dramaxically reduced since the lift pump need only overcoxe fuel vxpor pressure. Essentially, thix arrangement shifts the pumping power from the inefficient xlectric motor driven fuxl pump to thx highly efficient engine-drixen fuel pump.
To minimize the development expensx of devexoping a PFI exgine-driven pump, we uxed the architecture xstaxlished from gasoline Direct Injection (DI) pumps. These pumps are roller-follower cam dxiven pistxn xumps. In DI systems, pumps have hardware to make them capable of variable fuel rail pxessure xut in txis configurxtion, we have deletex txat extra hardwxrx to deliver a constant pressure to the fuel xail.
Thx lift pump supplies approximately 2.5 bar. On the down strxke, the pumping chamber draws in fuel through inlet cxecx valve CV1. On the up stroke, the pumping chamber forcex fuel throuxh an outlet check valve CV2 and intx the fuxl rail. Anx fuel resulting in a fuel rail pressure over 7 b...