Patent Publication Number: US-2016230727-A1

Title: Fuel injection pump

Description:
TECHNICAL FIELD 
     The present invention relates to techniques of a fuel injection pump. 
     BACKGROUND ART 
     Fuel injection pumps are known as pumps that deliver, at high pressure, a fuel to be injected into a combustion chamber of a diesel engine. The fuel injection pump delivers a fuel that is pressure-fed by allowing a plunger to vertically slide inside a plunger barrel to a plurality of delivery valves and pressure-feeds the fuel to a fuel injection nozzle from each of the delivery valves (Patent Document 1, for example). 
     In a diesel engine, it is necessary to significantly reduce “soot (hereinbelow, referred to as Sd)” due to restriction. In a diesel engine, it is effective to delay a fuel injection timing to significantly reduce Sd. On the other hand, in a diesel engine, the delay in the fuel injection timing significantly deteriorates a white smoke disappearance time (a time from engine start to the disappearance of white smoke). 
     On the other hand, the generation of white smoke also has a correlation with an initial injection rate. In a diesel engine, when the initial injection rate is high, a combustion temperature is reduced. The reduction in the combustion temperature results in imperfect combustion. The imperfect combustion results in the generation of white smoke. That is, the generation of white smoke can be reduced by reducing the initial injection rate. 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: JPH 11-44274 A 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     It is an object of the present invention to provide a fuel injection pump that enables white smoke in exhaust gas to be significantly reduced. 
     Solutions to the Problem 
     A fuel injection pump according to a first aspect of the present invention is configured to deliver, at high pressure, a fuel to be injected into a combustion chamber of a diesel engine, and includes a delivery valve disposed in the middle of a path for pressure-feeding the fuel from a plunger to a fuel injection nozzle and a damping valve disposed on a downstream side of the delivery valve. The damping valve includes a valve element which has an orifice formed on an axial part of the valve element and is biased toward an upstream side by a damping valve spring and a receiving element which has a passage hole formed on an axial part of the receiving element and is configured to abut against the valve element. A recess communicating with the passage hole is formed on a face of the valve element, the face facing the receiving element. 
     Preferably, in the fuel injection pump according to the first aspect of the present invention, the recess is formed in a cylindrical shape. 
     A fuel injection pump according to a second aspect of the present invention is configured to deliver, at high pressure, a fuel to be injected into a combustion chamber of a diesel engine, and includes a delivery valve disposed in the middle of a path for pressure-feeding the fuel from a plunger to a fuel injection nozzle and a damping valve disposed on a downstream side of the delivery valve. The damping valve includes a valve element which has an orifice formed on an axial part of the valve element and is biased toward an upstream side by a damping valve spring and a receiving element which has a passage hole formed on an axial part of the receiving element and is configured to abut against the valve element. A recess communicating with the passage hole is formed on a face of the receiving element, the face facing the valve element. 
     Preferably, in the fuel injection pump according to the second aspect of the present invention, the recess is formed in a cylindrical shape. 
     Effects of the Invention 
     According to the fuel injection pump of the present invention, it is possible to reduce the resistance produced in the second half of fuel injection, reduce the initial injection rate, and thereby significantly reduce white smoke in exhaust gas. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view showing the configuration of a fuel injection pump. 
         FIG. 2  is a schematic view showing the configuration of a delivery valve according to Embodiment 1. 
         FIG. 3  is a schematic view showing the configuration of a delivery valve according to Embodiment 2. 
         FIG. 4  is a schematic view showing the configuration of a delivery valve according to Embodiment 3. 
         FIGS. 5(A) to 5(C)  are schematic views showing the action of the delivery valve according to Embodiment 3. 
         FIG. 6  is a side view showing the configuration of a fuel injection pump according to Embodiment 4. 
         FIG. 7  is a side view showing the configuration of a fuel injection pump according to Embodiment 5. 
         FIG. 8  is a side view showing the configuration of a fuel injection pump according to Embodiment 6. 
         FIG. 9  is a side view showing the configuration of a fuel injection pump according to Embodiment 7. 
     
    
    
     EMBODIMENTS OF THE INVENTION 
     Embodiment 1 
     The configuration of a fuel injection pump  100  will be described with reference to  FIG. 1 . 
       FIG. 1  illustrates the fuel injection pump  100  in partially sectional view and side view. 
     The fuel injection pump  100  relates to Embodiment 1 of the fuel injection pump of the present invention. The fuel injection pump  100  is provided in a diesel engine. The fuel injection pump  100  delivers, at high pressure, a fuel to be injected into a combustion chamber of the diesel engine. 
     The fuel injection pump  100  includes a pump housing  102  which has a hole formed from the upper face toward the lower side thereof and a tubular plunger barrel  103  which is inserted into the hole of the pump housing  102 . A plunger  104  is vertically slidably inserted into the plunger barrel  103 . A pressure chamber  107  is formed above the plunger  104 . 
     A tappet  108  is inserted under the plunger  104  in such a manner that the tappet  108  can vertically slide inside the pump housing  102  integrally with the plunger  104 . A cam  109  abuts against the lower face of the tappet  108  through a roller  112 . The plunger  104  and the tappet  108  are biased downward by a plunger spring  105 . 
     The cam  109  is disposed on a cam shaft  110 . The cam shaft  110  is rotatably supported on the pump housing  102  of the fuel injection pump  100  through a cam bearing  111 . A delivery valve  10  is disposed above the plunger  104 . The delivery valve  10  will be described in detail below. 
     With such a configuration, the tappet  108  which is in sliding contact with the outer periphery of the cam  109  and the plunger  104  vertically slide in a reciprocating manner with the rotation of the cam shaft  110 , so that a fuel is pressure-fed by a fuel feed pump (not illustrated). The plunger  104  sliding toward the upstream side (downward) opens a barrel port  106 , and the pressure-fed fuel is thereby sucked into the pressure chamber  107 . The fuel sucked into the pressure chamber  107  is pressurized when the plunger  104  slides toward the downstream side (upward). 
     The configuration of the delivery valve  10  will be described with reference to  FIG. 2 .  FIG. 2  illustrates the delivery valve  10  in partially sectional view and side view. On the upper right side of  FIG. 2 , the configuration of a conventional valve element and a conventional receiving element, and the configuration of a valve element  15  and a receiving element  16  of the present embodiment are enlarged and compared. 
     The delivery valve  10  is provided with a tubular delivery valve case  11 , a delivery valve body  13 , and a delivery valve spring  14  which biases the delivery valve body  13  toward the delivery valve case  11 . 
     The delivery valve case  11  and the plunger barrel  103  are inserted into the hole which is formed on the pump housing  102  from the upper face toward the lower side thereof (refer to  FIG. 1 ). The delivery valve body  13  is vertically slidably inserted into the lower part of a spring housing section  12   d  of a casing  12  and biased toward the delivery valve case  11  (downward) by the delivery valve spring  14 . A space formed by the receiving element  16 , the spring housing section  12   d,  and the delivery valve body  13  is referred to as a delivery chamber R. 
     The casing  12  is a tubular member and inserted from the upper side of the fuel injection pump  100  into the hole which is formed on the pump housing  102  on the upper face thereof. A through hole is formed on an axial part of the casing  12 . A fuel discharge port  12   a,  a small-diameter fuel passage  12   b,  a guide body housing section  12   c,  the spring housing section  12   d,  and a delivery valve case fitting section  12   e  are formed inside the through hole of the casing  12  in this order from the upper side. 
     The fuel discharge port  12   a  is formed in a tapered shape expanding toward the downstream side on a downstream end of the through hole, and a high-pressure tube is connected to the fuel discharge port  12   a.  The small-diameter fuel passage  12   b  is formed under (on the upstream side of) the fuel discharge port  12   a  to receive one side of a damping valve spring  18 . The guide body housing section  12   c  is formed on the upstream side of the small-diameter fuel passage  12   b  to house a guide body  19  and a damping valve  17 . 
     The damping valve  17  includes the valve element  15  and the receiving element  16 . 
     The damping valve  17  is configured in such a manner that the valve element  15  is biased downward (toward the upstream side) by the damping valve spring  18  so as to abut against the receiving element  16 . 
     The valve element  15  faces the receiving element  16 . The valve element  15  is formed in a two-stage cylindrical shape and has an orifice  15   a  which vertically penetrates an axial part thereof. The valve element  15  has a cylindrical recess  15   b  which is recessed upward from the center of a face of the valve element  15 , the face facing the receiving element  16 . The recess  15   b  communicates with the orifice  15   a.  The recess  15   b  is formed in a cylindrical shape. The receiving element  16  is formed in a two-stage cylindrical shape and has a passage hole  16   a  which vertically penetrates an axial part thereof. 
     The spring housing section  12   d  is formed on the upstream side of the guide body housing section  12   c  to house the delivery valve spring  14  and the upper part of the delivery valve body  13 . The delivery valve case fitting section  12   e  which is fitted with the upper part of the delivery valve case  11  is formed under the spring housing section  12   d.    
     The action of the delivery valve  10  will be described. 
     When the pressure of the pressurized fuel inside the pressure chamber  107  (refer to  FIG. 1 ) exceeds a predetermined opening pressure for the delivery valve  10  and the damping valve  17 , the delivery valve body  13  and the valve element  15  slide toward the downstream side (upward) to open the delivery valve  10  and the damping valve  17 . Accordingly, the fuel is pressure-fed to a fuel injection nozzle (not illustrated) through the spring housing section  12   d,  the passage hole  16   a,  the small-diameter fuel passage  12   b,  and the fuel discharge port  12   a.    
     At this time, the resistance of the fuel flowing between the valve element  15  and the receiving element  16  immediately after the lift of the valve element  15  (in the first half of the fuel injection) is similar to that in a conventional configuration due to a small gap between the valve element  15  and the receiving element  16  even when the recess  15   b  is formed. However, when the lift of the valve element  15  exceeds a predetermined lift amount (in the second half of the fuel injection), the recess  15   b  sufficiently reduces a distance having the minimum fuel passage width (the minimum gap between the valve element  15  and the receiving element  16 ) from a conventional distance L 2  to a distance L 1 . Thus, the fuel injection amount is increased. 
     When this phenomenon is considered based on a fuel injection rate (a fuel injection amount per unit time), the fuel injection rate decreases in the first half of the fuel injection and increases in the second half of the fuel injection. That is, an initial injection rate of the diesel engine is reduced. 
     An effect of the delivery valve  10  will be described. 
     The delivery valve  10  makes it possible to reduce the initial injection rate of the fuel injection pump  100  and thereby significantly reduce white smoke in exhaust gas of the diesel engine. 
     Embodiment 2 
     The configuration of a delivery valve  20  will be described with reference to  FIG. 3 . 
       FIG. 3  illustrates the delivery valve  20  in partially sectional view and side view. On the upper right side of  FIG. 3 , the configuration of a conventional valve element and a conventional receiving element, and the configuration of a valve element  25  and a receiving element  26  of the present embodiment are enlarged and compared. 
     The delivery valve  20  relates to Embodiment 2 of the fuel injection pump of the present invention. A delivery valve case  21 , a casing  22 , a delivery valve body  23 , a delivery valve spring  24 , a damping valve spring  28 , and a guide body  29  of the delivery valve  20  respectively have configurations similar to the configurations of the delivery valve case  11 , the casing  12 , the delivery valve body  13 , the delivery valve spring  14 , the damping valve spring  18 , and the guide body  19  of the delivery valve  10 . Thus, description thereof will not be provided. 
     A damping valve  27  includes the valve element  25  and the receiving element  26 . 
     The damping valve  27  is configured in such a manner that the valve element  25  is biased downward (toward the upstream side) by the damping valve spring  28  so as to abut against the receiving element  26 . 
     The valve element  25  is formed in a two-stage cylindrical shape and has an orifice  25   a  which vertically penetrates an axial part thereof. The receiving element  26  is formed in a two-stage cylindrical shape and has a passage hole  26   a  which vertically penetrates an axial part thereof. The receiving element  26  has a cylindrical recess  26   b  which is recessed downward from the center of a face of the receiving element  26 , the face facing the valve element  25 . The recess  26   b  communicates with the orifice  25   a.  The recess  26   b  is formed in a cylindrical shape. 
     The action of the delivery valve  20  will be described. 
     When the pressure of the pressurized fuel inside the pressure chamber  107  exceeds a predetermined opening pressure for the delivery valve  20  and the damping valve  27 , the delivery valve body  23  and the valve element  25  slide toward the downstream side (upward) to open the delivery valve  20  and the damping valve  27 . Accordingly, the fuel is pressure-fed to a fuel injection nozzle (not illustrated) through a spring housing section  22   d , the passage hole  26   a,  a small-diameter fuel passage  22   b,  and a fuel discharge port  22   a.    
     At this time, the resistance of the fuel flowing between the valve element  25  and the receiving element  26  immediately after the lift of the valve element  25  (in the first half of the fuel injection) is similar to that in a conventional configuration due to a small gap between the valve element  25  and the receiving element  26  even when the recess  26   b  is formed. However, when the lift of the valve element  25  exceeds a predetermined lift amount (in the second half of the fuel injection), the recess  26   b  sufficiently reduces a distance having the minimum fuel passage width (the minimum gap between the valve element  25  and the receiving element  26 ) from a conventional distance L 2  to a distance L 1 . Thus, the fuel injection amount is increased. 
     When this phenomenon is considered based on a fuel injection rate (a fuel injection amount per unit time), the fuel injection rate decreases in the first half of the fuel injection, and the fuel injection rate increases in the second half of the fuel injection. That is, an initial injection rate of the diesel engine is reduced. 
     An effect of the delivery valve  20  will be described. 
     The delivery valve  20  makes it possible to reduce the initial injection rate of the fuel injection pump  100  and thereby significantly reduce white smoke in exhaust gas of the diesel engine. 
     Embodiment 3 
     The configuration of a delivery valve  30  will be described with reference to  FIG. 4 . 
       FIG. 4  illustrates the delivery valve  30  in partially sectional view and side view. 
     The delivery valve  30  relates to Embodiment  3  of the fuel injection pump of the present invention. A delivery valve case  31 , a casing  32 , a delivery valve body  33 , and a delivery valve spring  34  of the delivery valve  30  respectively have configurations similar to the configurations of the delivery valve case  11 , the casing  12 , the delivery valve body  13 , and the delivery valve spring  14  of the delivery valve  10 . Thus, description thereof will not be provided. 
     A damping valve  37  includes an inner valve element  35   i,  an outer valve element  35   o , a receiving element  36 , and a support  39 . The inner valve element  35   i  is biased downward (toward the upstream side) from the support  39  by an inner damping valve spring  38   i  so as to abut against the receiving element  36 . The outer valve element  35   o  is biased downward (toward the upstream side) from the casing  32  by an outer damping valve spring  38   o  so as to abut against the receiving element  36 . 
     The inner valve element  35   i  is formed in a two-stage cylindrical shape and has an orifice  35   a  which vertically penetrates an axial part thereof. The outer valve element  35   o  is formed in an annular shape. The receiving element  36  is formed in a two-stage cylindrical shape and has a passage hole  36   a  which vertically penetrates an axial part thereof. The support  39  is formed in a two-stage cylindrical shape and has a passage hole  39   a  which vertically penetrates an axial part thereof. 
     The outer valve element  35   o  is engaged with a stepped part of the inner valve element  35   i.  That is, a biasing force of the outer damping valve spring  38   o  and a biasing force of the inner damping valve spring  38   i  are applied to the inner valve element  35   i.    
     The action of the delivery valve  30  will be described with reference to  FIGS. 5(A) to 5(C) . 
       FIGS. 5(A) to 5(C)  illustrate the delivery valve  30  in partially sectional view and side view. 
     As shown in  FIG. 5(A) , when the pressure of the pressurized fuel inside the pressure chamber  107  exceeds a predetermined opening pressure for the damping valve  37 , the fuel pressure-fed through the passage hole  36   a  of the receiving element  36  overcomes the biasing forces of the inner damping valve spring  38   i  and the outer damping valve spring  38   o,  so that the inner valve element  35   i  and the outer valve element  35   o  are lifted toward the downstream side (upward) (in the first half of the fuel injection). At this time, the inner valve element  35   i  and the outer valve element  35   o  receive resistance produced by the biasing forces of the inner damping valve spring  38   i  and the outer damping valve spring  38   o.    
     As shown in  FIG. 5(B) , when the inner valve element  35   i  and the outer valve element  35   o  are further lifted toward the downstream side (upward), the upper end face of the inner valve element  35   i  comes into contact with the lower end face of the support  39 . 
     As shown in  FIG. 5(C) , when the upper end face of the inner valve element  35   i  comes into contact with the lower end face of the support  39 , the outer valve element  35   o  is separated from the inner valve element  35   i  and lifted toward the downstream side (upward) (in the second half of the fuel injection). At this point, since the outer valve element  35   o  receives resistance produced only by the biasing force of the outer damping valve spring  38   o , the lift amount increases. Thus, the fuel injection amount becomes larger than that in the first half of the fuel injection. 
     When this phenomenon is considered based on a fuel injection rate (a fuel injection amount per unit time), the fuel injection rate decreases in the first half of the fuel injection, and the fuel injection rate increases in the second half of the fuel injection. That is, an initial injection rate of the diesel engine is reduced. 
     An effect of the delivery valve  30  will be described. 
     The delivery valve  30  makes it possible to reduce the initial injection rate of the fuel injection pump  100  and thereby significantly reduce white smoke in exhaust gas of the diesel engine. 
     Embodiment 4 
     The configuration of a fuel injection pump  400  will be described with reference to  FIG. 6 . 
       FIG. 6  schematically illustrates the fuel injection pump  400 . 
     The fuel injection pump  400  relates to Embodiment  4  of the fuel injection pump of the present invention. The fuel injection pump  400  is similar to the fuel injection pump  100  according to Embodiment 1 except for a part particularly described below. 
     A recess  408   a  is formed on the lower face of a tappet  408 . There is not a roller between the recess  408   a  and the lower face of a tappet  408 . The recess  408   a  is formed in a circular arc shape when viewed from a direction perpendicular to a cam shaft  410 . The recess  408   a  varies a contact position between a cam  409  and the recess  408   a  depending on the shape of the cam  409 . Thus, the timing and amount of vertical reciprocating slide of a plunger  404  caused by the cam  409  are varied. That is, the fuel injection amount can be varied without changing the profile of the cam  409 . The recess  408   a  is formed so that the fuel injection amount increases in the second half of fuel injection. 
     Such a configuration enables an initial injection rate of the diesel engine to be reduced. That is, it is possible to reduce the initial injection rate of the fuel injection pump  400  and thereby significantly reduce white smoke in exhaust gas of the diesel engine. 
     Embodiment 5 
     The configuration of a fuel injection pump  500  will be described with reference to  FIG. 7 . 
       FIG. 7  illustrates the fuel injection pump  500  in partially sectional view and side view. 
     The fuel injection pump  500  relates to Embodiment 5 of the fuel injection pump of the present invention. The fuel injection pump  500  is similar to the fuel injection pump  100  according to Embodiment 1 except for a part particularly described below. 
     A capacity addition mechanism  510  communicates with a delivery chamber R. The capacity of the capacity addition mechanism  510  decreases as the engine speed increases and increases as the engine speed decreases. The capacity addition mechanism  510  is provided with a passage  511 , a cylinder chamber  512 , a fuel chamber  512   a,  a piston  513 , a solenoid  514 , and a controller  550 . 
     The cylinder chamber  512  forms the fuel chamber  512   a  by the piston  513 . The passage  511  allows the delivery chamber R formed on a casing and the fuel chamber  512   a  to communicate with each other. The piston  513  slides inside the cylinder chamber  512  to increase or reduce the capacity of the fuel chamber  512   a.  The solenoid  514  is connected to the controller  550  to drive the piston  513  to reciprocate. 
     The controller  550  is connected to the solenoid  514  and an engine speed senor  551  which detects the engine speed of an engine (not illustrated) provided with the fuel injection pump  500 . The controller  550  has a function of controlling the solenoid  514  to drive the piston  513  so as to reduce the capacity of the cylinder chamber  512  as the engine speed increases and controlling the solenoid  514  to drive the piston  513  so as to increase the capacity of the cylinder chamber  512  as the engine speed decreases. 
     The action of the capacity addition mechanism  510  will be described. With the capacity addition mechanism  510 , the capacity of the cylinder chamber  512  of the capacity addition mechanism  510  is added to the capacity of the conventional delivery chamber R. Thus, a time lag occurs when the injection pressure is transmitted to a fuel injection nozzle (not illustrated) to delay a fuel injection timing. That is, providing the capacity addition mechanism  510  delays the fuel injection timing over the entire engine speed (first control). 
     On the other hand, in the capacity addition mechanism  510 , the capacity of the cylinder chamber  512  is reduced as the engine speed increases. Thus, although the fuel injection timing is delayed over the entire engine speed by the first control, the time lag is eliminated before the injection pressure is transmitted to the fuel injection nozzle (not illustrated) to advance the fuel injection timing. That is, the fuel injection timing is advanced compared to that during the first control only when the engine speed is high (second control). 
     An effect of the capacity addition mechanism  510  will be described. 
     The capacity addition mechanism  510  enables the generation of Sd and deterioration in a white smoke disappearance time to be improved. That is, since the fuel injection timing is delayed over the entire engine speed by the first control and advanced by the second control only when the engine speed is high, the generation of Sd and the deterioration in the white smoke disappearance time can be improved. 
     Embodiment 6 
     The configuration of a fuel injection pump  600  will be described with reference to  FIG. 8 . 
       FIG. 8  illustrates the fuel injection pump  600  in partially sectional view and side view. 
     The fuel injection pump  600  relates to Embodiment 6 of the fuel injection pump of the present invention. The fuel injection pump  600  is similar to the fuel injection pump  100  according to Embodiment 1 except for a part particularly described below. 
     A capacity addition mechanism  620  communicates with a delivery chamber R. The capacity of the capacity addition mechanism  620  decreases as the engine speed increases and increases as the engine speed decreases. The capacity addition mechanism  620  is provided with a passage  621 , a cylinder chamber  622 , a piston  623 , a switching valve  624 , and a hydraulic pump  625 . 
     The passage  621 , the cylinder chamber  622 , a fuel chamber  622   a,  and the piston  623  respectively have configurations similar to the configurations of the passage  511 , the cylinder chamber  512 , and the piston  513  of Embodiment 5. Thus, description thereof will not be provided. 
     The cylinder chamber  622  is divided into the fuel chamber  622   a  and an operating oil chamber  622   b  by the piston  623 . The switching valve  624  is disposed between the hydraulic pump  625  and the cylinder chamber  622 . The switching valve  624  has a function of supplying an operating oil to the operating oil chamber  622   b  of the cylinder chamber  622  when the pressure of the operating oil fed from the hydraulic pump  625  becomes a predetermined pressure or more. The hydraulic pump  625  is driven by an engine provided with the fuel injection pump  600 . 
     The action of the capacity addition mechanism  620  will be described. With the capacity addition mechanism  620 , the capacity of the cylinder chamber  622  of the capacity addition mechanism  620  is added to the capacity of the conventional delivery chamber R. Thus, a time lag occurs when the injection pressure is transmitted to a fuel injection nozzle (not illustrated) to delay a fuel injection timing. That is, providing the capacity addition mechanism  620  delays the fuel injection timing over the entire engine speed (first control). 
     On the other hand, in the capacity addition mechanism  620 , when the operating pressure by the hydraulic pump  625  increases to a predetermined pressure or more as the engine speed increases, the switching valve  624  is switched to supply the operating oil to the operating oil chamber  62   b.  Accordingly, the piston  623  inside the cylinder chamber  622  moves toward the fuel chamber  622   a  to reduce the capacity of the fuel chamber  622   a.  Thus, although the fuel injection timing is delayed over the entire engine speed by the first control, the time lag is eliminated before the injection pressure is transmitted to the fuel injection nozzle (not illustrated) to advance the fuel injection timing. That is, the fuel injection timing is advanced compared to that during the first control only when the engine speed is high (second control). 
     An effect of the capacity addition mechanism  620  will be described. The capacity addition mechanism  620  enables the generation of Sd and deterioration in a white smoke disappearance time to be improved. That is, since the fuel injection timing is delayed over the entire engine speed by the first control and advanced by the second control only when the engine speed is high, the generation of Sd and the deterioration in the white smoke disappearance time can be improved. 
     Embodiment 7 
     The configuration of a fuel injection pump  700  will be described with reference to  FIG. 9 . 
       FIG. 9  illustrates the fuel injection pump  700  in partially sectional view and side view. 
     The fuel injection pump  700  relates to Embodiment 7 of the fuel injection pump of the present invention. The fuel injection pump  700  is similar to the fuel injection pump  100  according to Embodiment 1 except for a part particularly described below. 
     A capacity addition mechanism  730  communicates with a delivery chamber R. The capacity of the capacity addition mechanism  730  decreases as the engine speed increases and increases as the engine speed decreases. The capacity addition mechanism  730  is provided with a passage  731 , a cylinder chamber  732 , a piston  733 , and a synchronous link  734 . 
     The passage  731 , the cylinder chamber  732 , a combustion chamber  732   a,  and the piston  733  respectively have configurations similar to the configurations of the passage  511 , the cylinder chamber  512 , the combustion chamber  512   a,  and the piston  513  of Embodiment 5. Thus, description thereof will not be provided. 
     A regulator lever  752  is disposed on an engine provided with the fuel injection pump  700 . The regulator lever  752  is operated to turn to adjust the fuel injection amount of the fuel injection pump  100  to control the engine speed. 
     One end of the synchronous link  734  is turnably supported on the other end side of the piston  733 , and the other end of the synchronous link  734  is turnably supported on one end side of the regulator lever  752 . The synchronous link  734  supports the piston  733  and the regulator valve  752  so as to reduce the capacity of the cylinder chamber  732  when the regulator lever  752  is turned to control the engine speed at a high speed and increase the capacity of the cylinder chamber  732  when the regulator lever  752  is turned to control the engine speed at a low speed. 
     The action of the capacity addition mechanism  730  will be described. 
     With the capacity addition mechanism  730 , the capacity of the cylinder chamber  732  of the capacity addition mechanism  730  is added to the capacity of the conventional delivery chamber R. Thus, a time lag occurs when the injection pressure is transmitted to a fuel injection nozzle (not illustrated) to delay a fuel injection timing. That is, providing the capacity addition mechanism  720  delays the fuel injection timing over the entire engine speed (first control). 
     On the other hand, in the capacity addition mechanism  730 , the capacity of the cylinder chamber  732  is reduced by turning the regulator lever  752  so as to increase the engine speed. Thus, although the fuel injection timing is delayed over the entire engine speed by the first control, the time lag is eliminated before the injection pressure is transmitted to the fuel injection nozzle (not illustrated) to advance the fuel injection timing. That is, the fuel injection timing is advanced compared to that during the first control only when the engine speed is high (second control). 
     An effect of the capacity addition mechanism  730  will be described. 
     The capacity addition mechanism  730  enables the generation of Sd and deterioration in a white smoke disappearance time to be improved. That is, since the fuel injection timing is delayed over the entire engine speed by the first control and advanced by the second control only when the engine speed is high, the generation of Sd and the deterioration in the white smoke disappearance time can be improved. 
     INDUSTRIAL APPLICABILITY 
     The present invention is applicable to a fuel injection pump. 
     DESCRIPTION OF REFERENCE SIGNS 
     
         
           10 : Delivery valve 
           15 : Valve element 
           15   a : Orifice 
           15   b : Recess 
           16 : Receiving element 
           16   a : Passage hole 
           17 : Damping valve 
           100 : Fuel injection pump