CLIAMS:I Claim:

1 A governor for inline fuel injection pump comprising:
a pair of fly weights (105a) and (105b) in communication with a cam shaft (110);
characterized in that
a guide bushing comprising a first portion (115a) and a second portion (115b), said first portion (115a) connected to said pair of fly weights (105a) and (105b) and said first portion (115a) and said second portion (115b) are connected to each other through a spring and retainer assembly (120);
a linkage lever (130) comprising a first end and a second end, wherein said first end of said linkage lever (130) is fixed to said first portion (115a) of said guide bushing and is mounted pivotally on a guide lever (135) at a first pivot point (140), said linkage lever (130) adapted to move in accordance with said first portion (115a) of said guide bushing;
a fulcrum lever (145) comprising a first end and a second end, wherein said fulcrum lever (145) is mounted pivotally on said guide lever (135) at said first pivot point (140), and said second end is a second pivot point (155); and
a negative adaptation lever (150) comprising a first end and a second end, wherein first end of said negative adaption lever (150) is mounted pivotally at said second pivot point (155) and second end of said negative adaption lever (150) is connected to said linkage lever (130) such that said negative adaption lever (150) is enabled to swing between a maximum position and a minimum position in accordance with movement of said linkage lever (130).

2 The governor as claimed in claim 1, comprising a stopper (160) adjoined to said second pivot point (155), wherein said stopper (160) is adapted to restrict movement of said negative adaption lever (150) beyond said maximum position.

3 The governor as claimed in claim 1, wherein said first end of said fulcrum lever (145) is in hinge connection with a bottom portion (184) of a governor covering.

4 The governor as claimed in claim 1, wherein said guide lever (135) comprises a first end and a second end, wherein said first end is being fixed to said second portion (115b) of said guide bushing and said second end is in hinge connection with a top portion (180) of a governor covering.

5 The governor as claimed in claim 1, wherein said negative adaptation lever (150) is connected to a control rack 165 through a shackle lever (167).

6 The governor as claimed in claim 1, wherein said linkage lever (130) is fitted to a retainer of said spring and retainer assembly (120). ,TagSPECI:Field of the invention
[001] This invention relates to a governor for inline fuel injection pump.

Background of the invention
[002] Components in an inline fuel injection pump comprise a plunger and barrel assembly, delivery valve assembly, high pressure line, a control rack and fuel injection nozzle. Fuel injection quantity is required to be regulated depending on engine speed. During engine operation, the fuel injection quantity remains fixed for a defined speed range. As the engine speed increases above a maximum speed with respect to that defined speed range, the fuel injection quantity is required to be reduced.

[003] A variable speed governor is adapted to adjust the control rack position, which in-turn regulates the quantity of fuel injected, over a defined range of positions, based on the engine speed. The variable speed governor positions the control rack such that the fuel injection quantity remains fixed for a defined speed range and reduces when the engine speed is raised above the maximum speed with respect to that particular defined speed range. However if the engine is operating at a speed lower than the maximum speed, then no governing action takes place as the control rack halts its movement at a position that corresponds to the maximum speed with respect to that particular speed range. Therefore the quantity of fuel injected, when the engine is operating at lower speeds, is large and hence results in fuel wastage.

[004] To adjust the control rack when the engine is operating at a speed lower than the maximum speed, the pressure of fresh air at the intake manifold of the engine is measured. If it is determined that the pressure of fresh air is below a threshold value then it is inferred that the engine is operating at a speed lower than the maximum speed for that particular speed range. Upon such inference, the position of the control rack is altered further with respect to the position that corresponds to the maximum speed so that the quantity of fuel injected is reduced. However, such solution is limited to turbocharged engines only. Hence, there is still a need for a modified governor to alter the control rack position when the engine is operating at a speed lower than the maximum speed for a given operating speed range. An US patent number 5,325,831 discloses one such method of altering the control rack position.

Brief description of the accompanying drawings
[005] Figure 1 illustrates a governor, in accordance with one embodiment;

[006] Figure 2 is an exemplary graph that represents control rack positions at various engine speeds;

[007] Figure 3 and Figure 4 illustrates a governor that enables movement of the control rack when engine is being operated at a speed lower than maximum speed with respect to a defined speed range; and

[008] Figure 5 illustrates a governor that positions a control rack when engine is being operated at a speed higher than maximum speed with respect to a defined speed range.

Detailed description
[009] Figure 1 illustrates a governor for inline fuel injection pumps, in accordance with one embodiment.

[0010] The governor comprises a pair of fly weights 105a and 105b in communication with a cam shaft 110. The governor is characterized by a guide bushing comprising a first portion 115a and a second portion 115b. The first portion 115a is connected to the pair of fly weights 105a and 105b. Further the first portion 115a and the second portion 115b are connected to each other through a spring and retainer assembly 120. The governor is also characterized by a linkage lever 130 comprising a first end and a second end. The first end of the linkage lever 130 is connected to the first portion 115a of the guide bushing and mounted pivotally on a guide lever 135 at a first pivot point 140. The linkage lever 130 is adapted to move in accordance with the first portion 115a of the guide bushing. Further, the governor is characterized by a fulcrum lever 145 comprising a first end and a second end. The fulcrum lever 145 is mounted pivotally on the guide lever 135 at the first pivot point 140. The governor is also characterized by a negative adaption lever 150 comprising a first end and a second end. The first end of the negative adaption lever 150 is mounted pivotally on the fulcrum lever 145 at a second pivot point 155 and the second end of the negative adaption lever 150 is connected to the linkage lever 130 such that the negative adaption lever 150 is enabled to swing between a maximum position and a minimum position in accordance with movement of the linkage lever 130.

[0011] Referring to Figure 1, the flyweights 105a and 105b is in communication with a cam shaft 110 through a drive shaft 107. The flyweights 105a and 105b are pivotally mounted on a drive shaft 107 that is in communication with the cam shaft 110 of a fuel pump. When the cam shaft 110 rotates, the flyweights 105a and 105b develop a centrifugal force. The centrifugal force, developed by the flyweights 105a and 105b, is transmitted to a first portion 115a of the guide bushing through pressure arms 109a and 109b. The first portion of the guide bushing 115a and the second portion 115b of the guide bushing is connected to each other through the spring and retainer assembly 120. Stiffness of the spring in the spring and retainer assembly 120 is lesser than the stiffness of the spring 177 and the stiffness of the governor spring 170.

[0012] The first end of the linkage lever 130 is fixed to a retainer of the spring and retainer assembly 120 such that any movement of the first portion 115a of the guide bushing is imparted to the linkage lever 130. Also, the linkage lever 130 is pivotally mounted on the guide lever 135 at the first pivot point 140 as shown in Figure 1. The second end of the linkage lever 130 is connected to the second end of the negative adaption lever 150.

[0013] The guide lever comprises a first end and a second end. The first end is fixed to the second portion 115b of the guide bushing and the second end is in hinge connection with a top portion 180 of the governor covering.

[0014] The first end of the fulcrum lever 145 is in hinge connection with a bottom portion 185 of the governor covering. The fulcrum lever 145 is pivotally mounted on the guide lever 135 at the first pivot point 140 so that the fulcrum lever 145 can move in accordance with the movement of the guide lever 135. The second end of the fulcrum lever forms a second pivot point 155 as shown in Figure 1.

[0015] The first end of the negative adaption lever 150 is mounted pivotally at the second pivot point 155 as shown in Figure 1 and the second end of the negative adaption lever 150 is connected to the linkage lever 130 so that the negative adaption lever 150 can move in accordance with the movement of the linkage lever 130. Also the pivotal mounting at the second pivot point 155 enables the negative adaption lever 150 to swing between a maximum position and a minimum position in accordance with movement of the linkage lever 130. The negative adaption lever 150 is connected to the control rack 165 through a shackle lever 167. The control rack undergoes movement in accordance with the movement of the negative adaption lever 150 thereby controlling quantity of fuel injected.

[0016] The negative adaption lever 150 that controls movement of the control rack for regulating the fuel injection at various engine speeds is explained in detail in the following paragraphs.

[0017] When engine is being operated at low idle speed, the control lever 108 is at zero throttle position. During such low idle speed, the tension lever 175 is positioned away from the bottom portion 185 of the governor covering. Such positioning of the tension lever 175 corresponds to a control rack position that delivers minimum quantity of fuel so that the engine is not stalled at low idle speed. The control rack position that corresponds to the delivery of minimum fuel quantity is indicated at point 302a in an exemplary graph shown in Figure 2.

[0018] When the accelerator pedal is fully depressed, the control lever 108 is moved to a full throttle position as shown in Figure 3. The control lever 108 being at the full throttle position corresponds to a defined speed range at which the engine can be operated. Such movement of the control lever 108 moves a swiveling lever 117.

[0019] The movement of the swiveling lever 117 moves the tension lever 175 as the swiveling lever 117 is connected to the tension lever 175 through a governor spring 170. Such movement of the swiveling lever 117 stretches the governor spring 170, thereby a spring force is developed by the governor spring 170.

[0020] The tension lever 175 moves such that it abuts itself to a stopper 184 located at the bottom portion 185 of the governor covering as shown in Figure 3. Also, the negative adaption lever 150 is positioned at a minimum position that is away from the stopper 160 as shown in Figure 3.

[0021] Movement of the tension lever 175 results in movement of the control rack 165, for a specified distance, in the direction of the arrow 166 shown in Figure 3. Such specific movement of the control rack 165 in the direction of the arrow 166 corresponds to increase in fuel injection quantity. The movement of the control rack 165 in the direction of the arrow 166 is indicated by the line 302b in the exemplary graph shown in Figure 2. Further, the control rack 165 position remains constant for a specific time period as represented by the line 302c.

[0022] Such increase in fuel injection quantity leads to increase in engine speed. Hence even if the position of the control lever 108 is unchanged, the engine speed continues to increase since the engine begins to gain momentum due to the increase in the fuel injection quantity.

[0023] Due to such increase in the engine speed, the flyweights 105a and 105b fly out and hence exert a centrifugal force on the first portion 115a of the guide bushing. Due to the centrifugal force exerted, the first portion 115a of the guide bushing travels for a specific distance against a spring force in the direction of the arrow 712 in Figure. 4 thereby compressing the spring 120 as shown in Figure 4. The movement of the first portion 115a of the guide bushing in the direction of the arrow 712 is imparted to the first end of the linkage lever 130. Consequently, the second end of the linkage lever 130 undergoes angular movement in the opposite direction, indicated by the arrow 704 in Figure 4, as the linkage lever 130 is pivoted at the first pivot point 140. The angular movement of the linkage lever 130 about the first pivot point 140 is proportional to the distance travelled by the first portion 115a of the guide bushing in the direction of the arrow 712.

[0024] Due to the movement of the second end of the linkage lever 130 in the direction of the arrow 704, the negative adaption lever 150 also undergoes an angular displacement, from its minimum position, in the direction of the second end of the linkage lever 130. The angular displacement of the negative adaption lever 150 is proportional to the angular movement of the linkage lever 130 in the direction of the arrow 704.

[0025] As a result of the angular displacement of the negative adaption lever 150, the control rack 165 is further displaced by a specific distance in the direction of the arrow 704. Such displacement corresponds to further increase in the fuel injection quantity. Hence, the governor enables movement of control rack at lower engine speeds.

[0026] As the engine speed continues to increase, the first portion 115a of the guide bushing continues to move against the spring force of the spring in the spring and the retainer assembly 120 until the spring is compressed to a maximum extent. Such movement of the first portion 115a of the guide bushing until the spring 120 is compressed to a maximum extent results in the negative adaption lever 150 attaining the maximum position by swinging along the direction of the arrow 704 of Figure 4.

[0027] The movement of the control rack 165 that corresponds to movement of the negative adaption lever 150 from the minimum position to the maximum position along the direction of the arrow 704 is represented by the line 302d in the exemplary graph shown in Figure 2.

[0028] At the maximum position, the negative adaption lever 150 abuts to the stopper 160 as shown in Figure 4. The stopper 160 restricts the movement of the negative adaption lever 150 to the maximum position. The control rack position that corresponds to the negative adaption lever 150 being positioned at the maximum position is represented by the line 302e in the exemplary graph shown in Figure 2.

[0029] Similarly, as the engine speed decreases, the negative adaption lever 150 undergoes angular displacement from the maximum position until it reaches the minimum position. As a result of such movement of the negative adaption lever 150, the control rack moves correspondingly, in the opposite direction of the arrow 704, thereby decreasing the quantity of fuel injected as the engine speed decreases.

[0030] Hence, the angular displacement of the negative adaption lever 150 between the minimum position and the maximum position controls movement of a control rack 165 so that regulation of the fuel quantity can be achieved at lower engine speeds.

[0031] The quantity of the fuel injected when the negative adaption lever 150 is at the maximum position increases the engine speed further and hence the centrifugal force exerted by the fly weights 105a and 105b also increases. Further, when the spring included in the spring and retainer assembly 120 is compressed to the maximum extent, the first portion 115a of the guide bushing and the second portion 115b are considered to be a single unit thereby first portion 115a and the second portion 115b can move simultaneously as a single unit. As the centrifugal force exerted by the fly weights 105a and 105b increases, the first portion 115a and the second portion 115b, moves as a single unit, in the direction of the arrow 712, of Figure 5, against a spring force of the spring 177 until the spring 177 is compressed completely.

[0032] Such movement of the guide bushing moves the guide lever 135 in the direction of the arrow 714 thereby moving the fulcrum lever 145 in the same direction. Such movement of the fulcrum lever 145 moves the control rack 165 in the direction of the arrow 714. This reduces the quantity of the fuel injected. The movement of the control rack 165 until the spring 177 is completely compressed is represented by the line 302f of the exemplary graph in Figure 2.

[0033] When the spring 177 is completely compressed and the engine speed further increases, the tension lever 175 that is abutted to the stopper 184 of the governor covering moves away as shown in Figure 5. The movement of the tension lever 175 is imparted to the control rack 165. Such movement of the control rack 165 is represented by the line 302g. Such movement of the control rack 165 reduces the quantity of fuel delivered at engine speeds higher than the maximum speed of the defined speed range.

[0034] The angular displacement of the negative adaption lever between the minimum and maximum position displaces the control rack at lower engine speeds since the first portion 115a of the guide bushing undergoes movement at lower engine speeds against the spring force of the spring included in the spring and retainer assembly 120. Also, the stiffness of the spring is such that it undergoes compression due to the movement of the first portion 115a of the guide bushing during lower engine speeds. The displacement of the control rack is thereby used to regulate the quantity of fuel injected. Hence, the fuel injection quantity can be correctively adjusted even at lower engine speed.

[0035] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to leverage and dimensions of various levers are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.