Claims:We Claim
1. A governor (100) for an inline fuel injection pump, said governor (100) comprising:
a pair of fly weights (105a) and (105b) coupled to a cam shaft (110);
a guide bushing (116), a first end of said guide bushing (116) abutting said pair of fly weights (105a) and (105b);
a guide lever (135) coupled to said guide bushing (116);
a fulcrum lever (145) coupled to a governor covering (185) and connected to said guide lever (135) at a pivotal point (140); characterized in that
a retractable mechanism (143) coupled to said governor covering (185) of said governor (100) and adapted to move from a first position to a second position, said retractable mechanism (143) comprising:
a body (144); and
a screw (147) positioned within said body (144), said screw (147) comprising a head portion (149), and a stem (151) coupled to said head portion (149), and wherein a movement of said fulcrum lever (145) is restricted when the retractable mechanism (143) moves from the first position to the second position.

2. The governor (100) for an inline fuel injection pump in accordance with Claim 1 further comprising a spring member (153) positioned between said head portion (149) and said body (144).

3. The governor (100) for an inline fuel injection pump in accordance with Claim 2 further comprising a control rack (165) coupled to said fulcrum lever (145), and wherein a movement of said control rack (165) is restricted when said head portion (149) moves from the first position to the second position. , Description:Field of the invention
[0001] This invention relates to a governor for an inline fuel injection pump.

Background of the invention
[0002] IN Patent Application Number 4406/CHE/2013 describes a governor for an inline fuel injection pump. The governor includes a guide bushing comprising a first portion and a second portion. The first portion and the second portion are connected to each other via a spring and retainer assembly. The governor also includes a linkage lever comprising a first end and a second end. The first end of the linkage lever is fixed to the first portion of the guide bushing. The governor further includes a fulcrum lever mounted pivotally on a guide lever. Further, the governor includes a negative adaptation lever enabled to swing between a maximum position and a minimum position in accordance with a movement of the linkage lever.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a governor for an inline fuel injection pump in accordance with one embodiment of the invention.

Detailed description of the invention
[0004] A governor 100 for an inline fuel injection pump is described. The governor 100 comprises a pair of fly weights 105a and 105b coupled to a cam shaft 110 and a guide bushing 116, a first end of the guide bushing 116 abutting the pair of fly weights 105a and 105b. A guide lever 135 is coupled to the guide bushing 116. A fulcrum lever 145 is coupled to a governor covering 185 and connected to the guide lever 135 at a pivotal point 140. A retractable mechanism 143 is coupled to the governor covering 185 of the governor 100 and adapted to move from a first position to a second position. The retractable mechanism 143 comprises a body 144, and a screw 147 positioned within the body 144, the screw 147 comprising a head portion 149, and a stem 151 coupled to the head portion 149, and wherein a movement of the fulcrum lever 145 is restricted when the retractable mechanism 143 moves from the first position to the second position.

[0005] Figure 1 illustrates a governor 100 for an inline fuel injection pump. The governor 100 comprises a pair of fly weights 105a and 105b in communication with a cam shaft 110. The governor 100 is characterized by a guide bushing 116 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 100 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 116 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 116. Further, the governor 100 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 100 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.

[0006] Referring to Figure 1, the flyweights 105a and 105b are in communication with a cam shaft 110 through a drive shaft 107. The flyweights 105a and 105b are pivotally mounted on the 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 centrifugal force. The centrifugal force developed by the flyweights 105a and 105b is transmitted to a first portion 115a of the guide bushing 116 through pressure arms 109a and 109b. The first portion 115a of the guide bushing 116 and the second portion 115b of the guide bushing 116 is connected to each other through the spring and retainer assembly 120. The 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.

[0007] 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 116 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.

[0008] The guide lever 135 comprises a first end and a second end. The first end is fixed to the second portion 115b of the guide bushing 116 and the second end is in hinge connection with a top portion 180 of the governor covering 185.

[0009] The first end of the fulcrum lever 145 is in hinged connection with a bottom portion of the governor covering 185. The fulcrum lever 145 is pivotally mounted on the guide lever 135 at the first pivot point 140 such that the fulcrum lever 145 can move in accordance with the movement of the guide lever 135. The second end of the fulcrum lever 145 forms a second pivot point 155 as shown in Figure 1.

[0010] 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 165 undergoes movement in accordance with the movement of the negative adaption lever 150 thereby controlling a quantity of fuel injected.

[0011] The negative adaption lever 150 that controls movement of the control rack 165 for regulating the fuel injection at various engine speeds is explained in detail in the following paragraphs.

[0012] When the engine is being operated at low idle speed, the control lever 108 is at its zero throttle position. During such low idle speed, the tension lever 175 is positioned away from the bottom portion of the governor covering 185. 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. When the accelerator pedal is fully depressed, the control lever 108 is moved to a full throttle position. 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. 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.

[0013] 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. Such specific movement of the control rack 165 in the direction of the arrow 166 corresponds to increase in fuel injection quantity. Such increase in the 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.

[0014] 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 116. Due to the centrifugal force exerted, the first portion 115a of the guide bushing 116 travels for a specific distance against a spring force in the direction of the arrow 712 thereby compressing the spring 120. The movement of the first portion 115a of the guide bushing 116 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, 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 116 in the direction of the arrow 712.

[0015] 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.

[0016] 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 the control rack 165 at lower engine speeds.

[0017] As the engine speed continues to increase, the first portion 115a of the guide bushing 116 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 116 until the spring in the spring and the retainer assembly 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. At the maximum position, the negative adaption lever 150 abuts to the stopper 160. The stopper 160 restricts the movement of the negative adaption lever 150 to the maximum position.

[0018] 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 165 moves correspondingly in the opposite direction of the arrow 704, thereby decreasing the quantity of fuel injected into the engine.

[0019] Hence, the angular displacement of the negative adaption lever 150 between the minimum position and the maximum position controls movement of the control rack 165 so that regulation of the fuel quantity can be achieved at lower engine speeds.

[0020] 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 116 and the second portion 115b are considered to be a single unit. Thereby the 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, against a spring force of the spring 177 until the spring 177 is compressed completely.

[0021] Such movement of the guide bushing 116 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.

[0022] 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 185 moves away. The movement of the tension lever 175 is imparted to the control rack 165. 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.

[0023] The angular displacement of the negative adaption lever 150 between the minimum and maximum position displaces the control rack 165 at lower engine speeds since the first portion 115a of the guide bushing 116 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 165 is thereby used to regulate the quantity of fuel injected. Hence, the fuel injection quantity can be correctively adjusted even at lower engine speeds.

[0024] A retractable mechanism 143 is coupled to the governor covering 185 of the governor 100. The retractable mechanism 143 may be adapted to move from a first position to a second position. The second position is closer to the fulcrum lever 145 than the first position. The retractable mechanism 143 comprises a body 144 and a screw 147 that is positioned within the body 144. The screw 147 comprises a head portion 149 and a stem 151 that is coupled to the head portion 149. The stem 151 of the screw 147 is inserted within the body 144 of the retractable mechanism 143 and fastened to a retractable member 179. A spring member 153 is positioned between the head portion 149 and the governor covering 185.

[0025] In its equilibrium position, the screw 147 of the retractable mechanism 143 is at a first position. When the retractable member 143 is manually moved by a user, the screw 147 of the retractable mechanism 143 is moved from the first position to the second position. The movement of the screw 147 causes the head portion 149 to be moved from the first position to the second position against a force of the spring member 116. A movement of the fulcrum lever 145 is restricted when the retractable mechanism 143 moves from the first position to the second position.

[0026] When the fulcrum lever 145 is rotated in the anticlockwise direction, the rotation of the fulcrum lever 145 is translated to a movement of the control rack 165. The movement of the control rack 165 facilitates increasing a quantity of fuel that is delivered from the high pressure fuel pump. Therefore, when the retractable mechanism 143 is moved from the first position to the second position, the head portion 149 is moved from the first position to the second position, thereby causing a restriction in the movement of the fulcrum lever 145 that abuts against the head portion 149 of the screw 147. The restriction in the movement of the fulcrum lever 145 causes a restriction in the movement of the control rack 165. The restriction in the movement of the control rack 165 limits the quantity of fuel that is delivered from the high pressure fuel pump. The limitation to the quantity of fuel that is delivered from the high pressure fuel pump correspondingly limits the torque and power that may be delivered by the engine.

[0027] When the retractable mechanism 143 is moved from the first position to the second position, the head portion 149 is moved from the first position to the second position. The movement of the head portion 149 from the first position to the second position causes a restriction in the rotation of the fulcrum lever 145. The restriction in the rotation of the fulcrum lever 145 causes a restriction in the rotation of the negative adaptation lever 150 that is pivoted to the second pivot point 155. The restriction in the rotation of the negative adaptation lever 150 causes a restriction in the movement of the shackle lever 167. The restriction in the movement of the shackle lever 167 causes a restriction in the movement of the control rack 165. The restriction in the movement of the control rack 165 causes a reduced quantity of fuel to be delivered from the high pressure fuel pump.

[0028] A working of the governor 100 for the inline fuel injection pump is described as an example. When it is desired to reduce a torque on the engine, the retractable member 179 is pressed by the user. Therein, the head portion 149 of the screw 147 is moved from the first position to the second position against a resistance of the spring member 116. Due to the movement of the head portion 149 of the screw 147 from the first position to the second position, a movement of the fulcrum lever 145 is restricted in the anticlockwise direction. Due to the restriction in the movement of the fulcrum lever 145 in the anticlockwise direction, the movement of the control rack 165 is restricted. Due to the restriction in the movement of the control rack 165, the torque and power supplied by the engine is restricted. Therefore, the high pressure fuel pump can be operated at reduced loads, thereby improving the fuel efficiency of the engine.

[0029] 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.