High-pressure fuel feed pump

Abstract

A high-pressure fuel feed pump force-feeding fuel to a common rail for storing high-pressure fuel, comprising a fuel force-feeding means for force-feeding fuel and a fuel oil quantity regulating means for regulating the amount of fuel oil flowing into a compression chamber, the fuel oil quantity regulating means further comprising a fuel path leading the fuel sucked from a fuel tank to the compression chamber and a throttle valve installed in the fuel path and changing the cross-sectional area of the fuel path so as to vary the quantity of the fuel oil passing therethrough, wherein the throttle valve is slid in the direction generally perpendicular to the flowing direction of the fuel passing through the inside of the fuel path so that a valve disc regulating the fuel flow rate can be moved smoothly without being obstructing by a fluid pressure.

1 . (amended) a high-pressure fuel feed pump that is employed in a fuel injection system for injecting fuel into a combustion chamber of an internal combustion engine to force feed the fuel into a common rail where high-pressure fuel is stored, comprising: 
 a fuel force-feeding means that includes a compression space into which the fuel flows and sends out the fuel delivered into said compression space after compressing the fuel through a reciprocal movement of a plunger; and    a fuel oil quantity regulating means that regulates the quantity of fuel oil flowing into said compression space, characterized in that: 
 said fuel oil quantity regulating means includes a fuel path through which the fuel drawn out of a fuel tank is guided into said compression space and a throttle valve that is provided in said fuel path and changes the cross sectional area of said fuel path to vary the quantity of said fuel oil passing through said fuel path;  
 and the direction along which the fuel flows through said fuel path connected to a upstream side of said throttle valve and the direction along which the fuel flows through said fuel path connected to a downstream side of said throttle valve are both set substantially perpendicular to the direction along with said throttle valve slides.  
   
     
     
         2 . A high-pressure fuel feed pump according to  claim 1 , characterized in that: 
 said fuel oil quantity regulating means comprises: 
 an elastic member that applies force to said throttle valve along the closing direction;  
 an orifice formed inside the said path through which the fuel having been drawn from said fuel tank flows;  
 a pressure chamber provided to apply force to said throttle valve along the opening direction by using the pressure of the fuel having passed through said orifice and flowed therein; and  
 a pressure regulating valve that is provided within a first return path connecting said pressure chamber with said fuel tank and is electronically controlled by a specific control device.  
   
     
     
         3 . A high-pressure fuel feed pump according to  claim 2 , characterized in that: 
 a second return path communicating with said fuel tank is connected to the pressure chamber; and    an emergency stop valve that opens when specific conditions are present is provided in said second return path.    
     
     
         4 . A high-pressure fuel feed pump according to  claim 3 , characterized in that: 
 said specific conditions are;    the level of the pressure inside said common rail is equal to or higher than a predetermined level and said pressure regulating valve has remained in an open state over a predetermined length of time or longer.