I. Field of the Invention
The present invention relates generally to direct injection internal combustion engines and, more particularly, to a fuel system for such engines which reduces the stress imposed on the fuel system components.
II. Description of Related Art
Direct injection internal combustion engines are becoming increasingly popular in the automotive industry due in large part to their high efficiency and fuel economy. In such a direct injection engine, at least one fuel injector is mounted in a bore formed in the engine block which is open directly to the internal combustion chamber. A high pressure fuel rail is coupled to the fuel injector which, when open under control of the engine control unit, injects fuel directly into the internal combustion engine.
Since the injectors of the direct injection engine are open directly to the internal combustion chamber, the fuel in the fuel rails must necessarily be maintained at a relatively high pressure. Typically, a cam driven piston pump is used to pressurize the fuel rail.
One disadvantage of direct injection internal combustion engines, however, is that the fuel system components move slightly relative to each other in response to the high pressure fuel injection pulses and pump pulses. This, in turn, imparts stress on the fuel system components which can result in cracking or other component failure.
The present invention provides a device for reducing movement of the fuel rails in a direct injection fuel engine thereby reducing mechanical stress on those components.
In brief, the present invention provides several different approaches for reducing movement of the fuel rail in the fuel system. In one embodiment of the invention, a clamp extends across and is secured to both side by side fuel rails. By clamping the rails together, movement of the rails relative to the other fuel system components is reduced. Furthermore, the fuel rails may be either rigidly clamped together or may be resiliently clamped together with an elastomeric member.
In another form of the invention, a moving mass is attached to the fuel rails with a resilient member. Consequently, movement of the moving mass opposes any movement of the rails thus effectively canceling the movement of the rails during operation of the fuel system.
In still another embodiment of the invention, a flexible fluid conduit fluidly connects the fuel rails to the fuel injectors. This flexible fluid conduit thus reduces or altogether eliminates movement of the fuel rails caused by movement of the fuel injectors.
A better understanding of the present invention will be had upon reference to the following detailed description when read in conjunction with the accompanying drawing, wherein like reference characters refer to like parts throughout the several views, and in which:
With reference first to
At least one fuel injector 26 is associated with each combustion chamber 24. Each fuel injector 26 is positioned within a fuel injector bore 28 formed in the engine block 22 which is open to the combustion chambers 24. Each fuel injector 26, furthermore, is then fluidly coupled to a fuel rail 30 having an internal fuel chamber 32. A high pressure fuel pump (not shown) provides pressurized fuel to the fuel rail chambers 32 which, in turn, supply that pressurized fuel to the injectors 26. Furthermore, the fuel injectors illustrated in
Typically, the fuel injectors 26 are rigidly secured to their associated fuel rail 30. Upon each injection of fuel, the fuel injector 26 moves slightly away from the combustion chamber 24 which causes a like movement in its associated fuel rail 30. Such movement of the fuel rail 30 in turn imparts mechanical stress on the fuel system components.
With reference now to
A moving mass 44 is also secured to the clamp 40 by a resilient member or spring 46. The resilient member 46 allows the moving mass 44 to move relative to the clamp 40 and thus relative to the fuel rails 30.
In operation, as the fuel injectors impart movement to their associated fuel rails 30, the moving mass 44 moves thus effectively canceling any movement of the fuel rails 30. Furthermore, the clamp 40 itself alone reduces movement of the fuel rails 30 during operation of the internal combustion engine.
Although two fuel rails 30 are indicated in
With reference now to
In practice, the clamp 50, by rigidly securing the fuel rails 30 together, reduces movement of the fuel rails 30 and the resultant mechanical stress on the fuel system components from such movement.
With reference now to
With reference now to
In practice, the dampener 70 dampens vibrations of the fuel rails 30 in a lateral direction as indicated by arrows 78 in
With reference now to
Consequently, as best shown in
With reference now to
A resilient member 102, preferably constructed of an elastomeric material, is disposed across the top of the clamp 100. A moving mass 104 is then positioned within the resilient member 102 so that the resilient member 102 is sandwiched in between the moving mass 104 and the clamp 100.
In operation, the resilient member 102 allows the moving mass 104 to move slightly relative to the fuel rails 30. The moving mass 104, by moving, dampens the movement of the rails 30 and reduces component stress.
With reference now to
Still referring to
In order to secure the locator 120 to the engine block, the injector bore 28 includes an internally threaded portion 126 at its outer end. Consequently, by threadably securing the locator to the engine block 20, the locator 120 simply, but effectively, locks the fuel injector 26 against axial movement relative to the engine block.
Alternatively, the fuel injector 26 can be made of a non-metallic material with the threads to engage the thread portion 126 on the engine block formed integrally on the fuel injector 26.
From the foregoing, it can be seen that the present invention provides several different devices for reducing, or altogether eliminating, movement of the fuel rail relative to the engine block. Stress on the fuel system components resulting from movement of the fuel rail relative to the engine block during operation of the internal combustion engine is substantially reduced.
Having described our invention, however, many modifications thereto will become apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.