초록 ▼

A fuel system for an engine is disclosed. The fuel system has a first source configured to pressurized fuel to a first pressure, and a second source configured to pressurized fuel to a second pressure. The fuel system also has a fuel injector configured to receive fuel at the first pressure and the

A fuel system for an engine is disclosed. The fuel system has a first source configured to pressurized fuel to a first pressure, and a second source configured to pressurized fuel to a second pressure. The fuel system also has a fuel injector configured to receive fuel at the first pressure and the second pressure, and a valve disposed between the fuel injector and the first and second sources. The valve is configured to modify the pressure of fuel from the first source based on a pressure of fuel from the second source.

대표청구항 ▼

What is claimed is: 1. A fuel system for an engine, comprising: a first source configured to pressurize fuel to a first pressure; a second source configured to pressurize fuel to a second pressure; a fuel injector configured to receive fuel at the first pressure and the second pressure; and a valve

What is claimed is: 1. A fuel system for an engine, comprising: a first source configured to pressurize fuel to a first pressure; a second source configured to pressurize fuel to a second pressure; a fuel injector configured to receive fuel at the first pressure and the second pressure; and a valve disposed between the fuel injector and the first and second sources, the valve being configured to modify the pressure of fuel from the first source by selectively passing a portion of the fuel from the first source to a drain based on a pressure of fuel from the second source. 2. The fuel system of claim 1, wherein the valve is further configured to selectively pass fuel from only the first source to the fuel injector. 3. The fuel system of claim 1, wherein the valve includes: a first valve element disposed between the first source and the fuel injector, the first valve element movable between a first position at which the fuel from the first source is directed to only the fuel injector, and a second position at which a portion of the fuel from the first source is directed to a drain; and a second valve element disposed between the second source and an end of the first valve element, the second valve element movable between a first position at which fuel from the second source is directed to the end of the first valve element to bias the first valve element toward its second position, and a second position at which fuel from the end of the first valve element is directed to a drain. 4. The fuel system of claim 3, further including a third valve element disposed between the second source and the first valve element, the third valve element movable between a first position at which fuel from the first source is passed to a drain and a second position at which fuel from the first source is blocked from the drain, wherein the movement is in response to a pressure differential between the fuel from second source and the fuel from the first source. 5. The fuel system of claim 4, wherein the fuel from the first source is at a higher pressure than the fuel from the second source. 6. The fuel system of claim 5, wherein modifying includes only lowering the pressure of the fuel from the first fuel source. 7. The fuel system of claim 3, further including a piezo device configured to move the second valve element between the first and second positions. 8. The fuel system of claim 1, further including a bypass circuit configured to pass fuel from the second source to fuel injector. 9. A method of injecting fuel, the method comprising: pressurizing a first fuel stream; pressurizing a second fuel stream; modifying the pressure of the first fuel stream by selectively draining a portion of the first fuel stream based on a pressure of the second fuel stream; and injecting the first fuel stream at the modified pressure. 10. The method of claim 9, further including selectively injecting only the first fuel stream and only the second fuel stream. 11. The method of claim 9, wherein selectively draining a portion of the first fuel stream lowers the pressure of the first fuel stream. 12. The method of claim 9, wherein the first fuel stream is pressurized to a higher pressure than the second fuel stream. 13. An engine, comprising: a block forming at least one combustion chamber; a crankshaft rotationally disposed within the block; a first fuel pump operatively driven by the crankshaft to pressurize fuel to a first pressure; a second fuel pump operatively driven by the crankshaft to pressurize fuel to a second pressure lower than the first; a fuel injector configured to receive the fuel from the first and second fuel pumps and selectively inject the fuel into the at least one combustion chamber; and a valve disposed between the fuel injector and the first and second fuel pumps, the valve being configured to: lower the pressure of fuel from the first fuel pump based on the pressure of fuel from the second fuel pump; and selectively pass fuel from only the first source to the fuel injector. 14. The engine of claim 13, wherein: the valve lowers the pressure of the fuel from the first source by selectively passing a portion of the fuel from the first source to a drain; and the portion of the fuel from the first source selectively passed to the drain is dependent on a pressure of the fuel from the second source. 15. The engine of claim 13, wherein the valve includes: a first valve element disposed between the first source and the fuel injector, the first valve element movable between a first position at which the fuel from the first source is directed to only the fuel injector, and a second position at which a portion of the fuel from the first source is directed to a drain; and a second valve element disposed between the second source and an end of the first valve element, the second valve element movable between a first position at which fuel from the second source is directed to the end of the first valve element to bias the first valve element toward its second position, and a second position at which fuel from the end of the first valve element is directed to a drain. 16. The engine of claim 15, further including a third valve element disposed between the second source and the first valve element, the third valve element movable between a first position at which fuel from the first source is passed to a drain and a second position at which fuel from the first source is blocked from the drain, wherein the movement is in response to a pressure differential between the fuel from second source and the fuel from the first source. 17. The engine of claim 15, further including a piezo device configured to move the second valve element between the first and second positions.