CLIAMS:I Claim:
1. A Governor for a Fuel Injection pump, said governor comprising;
at least a pair of flyweights (102);
a fulcrum lever (104);
a linkage lever (106) connecting said fulcrum lever (104) to a control rack (108); characterized in that
a solenoid (110);
a hinge(112); and
a hinge lever (114).
said solenoid (110) connected to one end of said hinge lever (114) while another end of said hinge lever (114) interfaces with said fulcrum lever(104) via said hinge (112).
2. The governor of claim1, wherein said governor is mounted on an inline fuel injection pump.
3. The governor of claim1, wherein said solenoid 110 is mounted in the governor
,TagSPECI:The following specification particularly describes the invention and the manner in which it is to be performed.

Field of the invention
[001] This invention relates to the field of governors in a fuel injection pump.

Background of the invention
[002] Cold starting phenomena is a common problem encountered in automotive engines when the vehicle’s engine temperature is cold relative to its normal operating temperature. Starting a vehicle during cold start condition usually involves supplying an increased quantity of fuel during the initial stage of cold starting. Once the vehicle is started it is observed that there is a drop from the initial drastic demand for fuel and the fuel demands becomes further less as the vehicle reaches idle condition. The supply of fuel from the fuel injection pump is controlled by means of a control rack; the control rack interfaces the governor with the fuel injection pump. There is a need for the vehicle to ramp up faster from zero speed to idle condition, but with the existing fuelling trend between zero speed to idle speed, engine takes longer time to ramp up & stabilize at idle speed. Hence there is a need to shape the fuelling trend for each type of engine.

[003] Prior art patent application JP 2002155763 discloses a fuel injection equipment for automotive diesel engine, having solenoid installed at back side of governor which limits movement of control rack before reaching start up position during engine start up. A governor is attached to a fuel injection pump which moves a control rack to a start up position during engine start up, to increase fuel injection quantity. A solenoid is attached at back side of the governor, which limits movement of control rack before reaching the start up position during engine start up based on the coolant temperature, so that rack does not move more than the start up position after engine starts or when coolant temperature is beyond a particular threshold temperature.

Brief description of the accompanying drawings
[004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:
[005] FIG. 1 illustrates a governor for a fuel injection pump.

Detailed description of the embodiments
[006] FIG. 1 illustrates a governor for a fuel injection pump. The governor comprises at least a pair of flyweights 102, a fulcrum lever 104, and a linkage lever 106 connecting the fulcrum lever 104 to a control rack 108. The control rack is indicated to have two positions; position A indicates highest fuel delivery and B indicates fuel delivery during low idle speed of the engine. The flyweights 102 are connected to the linkage lever 106 with the help of the fulcrum lever 104. The governor is characterized in having a solenoid 110, a hinge 112, and a hinge lever 114. One end of the hinge lever 114 is connected to the solenoid 110 while another end of the hinge lever 114 interfaces with the fulcrum lever 104 via the hinge 112. The hinge 112 divides the length of the hinge lever 114 in a specified ratio. The ratios of the length of the lever depends upon the movement of the control rack, the point of interface of the hinge lever 114 on to the fulcrum lever 104 and the total movement of hinge lever 114 when solenoid is energized.

[007] The function of the solenoid 110 is to control the movement of the hinge lever 114 and thereby provide an additional stiffness to the fulcrum lever 104 during cold starting condition of the engine. This in turn will result in controlled movement of the control rack 108. The solenoid 110 is configured to receive information from the electronic control unit (ECU) during cold starting. The solenoid 110 may be excited through the ignition switch, once the solenoid 110 is excited, the hinge lever 114 is pulled upwards and away from the hinge 112, this causes the fulcrum lever 104 to move towards the control rack 108 pushing the control rack 108 to the delivery position A. Depending upon the stiffness of the starting spring the movement of the control rack 108 is regulated with respect to the movement of the flyweights 102.

[008] Before starting of the engine, the flyweights 102 are at rest and the starting spring moves the control rack 108 for maximum stroke i.e. towards the position A. This will ensure sufficient fuel to start the engine. When the engine starts the flyweights 102 move outwardly with respect to one another. At this stage the fulcrum lever pulls the control rack 108 towards the point B against the stiffness of the starting spring thereby reducing fuel delivery to the engine. Since, point B indicates fuel delivery at low idle speed of the engine, when the control rack 108 reaches point B, the solenoid 110 is excited. The excitation of solenoid 110, causes the hinge lever 114 to pulled away from the hinge 112, the hinge lever 114 pushes the fulcrum lever 104 against the starting spring. The activated solenoid 110 then holds the control rack 108 at a constant position thereby ensuring minimum constant fuel delivery to the fuel injection pump. The solenoid holds the control rack 108 at a constant position till such time during which the engine is idling. The solenoid is configured to be de-excited during ramp up phase that follows the idling phase. During ramp up phase the control rack 108 movement is only dependent on the movement of flyweights 102.

[009] The stiffness of the starting spring with respect to the governor force generated by rotation of the flyweights 102 determines control rack 108 position during engine speed increase from zero speed to low idle speed in the engine start process. By using the solenoid 110, we have additional flexibility to maintain constant position of the control rack 108, during idling, thereby ensuring minimum fuel delivery during idling condition.

[0010] Consider an example of using the above mentioned governor for controlling the fuelling rate in a fuel injection pump. Once the engine is started during cold start, initially there is an increased demand for fuel and that corresponds to the maximum position of the control rack 108. The control rack 108 is generally calibrated for a traverse between approximately 0mm to 21 mm. The engine tries to reach the idle condition, through progressive drop in fuel demand and retraction of control rack 108, the solenoid when excited 110 holds the control rack 108 at a given position, thereby ensuring adequate fuelling for a given position of the control rack 108. This means that even during idling the engine continues to receive a certain minimum and constant quantity of fuel, this ensures faster ramp up leading to a quick warm up of the engine.

[0011] Upon ramp up of the engine, the solenoid 110 is de-excited through the signals from the ECU; the movement of the control rack 108 is then dependent only with respect to the movement of flyweights 102.

[0012] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of position of the hinge, shape of the hinge lever and position the solenoid and mounting of the governor. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims