JP4081456B2 - Fuel injection pump - Google Patents

Description

  The present invention relates to a configuration for controlling the injection timing of a fuel injection pump for a diesel engine, and more particularly to a configuration for changing the injection timing at the start by a lead formed on a plunger. .

  2. Description of the Related Art Conventionally, there has been known a fuel injection pump having a configuration in which a plunger is slid vertically in a plunger barrel to compress fuel and pressure-feed it to a fuel injection nozzle via a discharge valve. In this fuel injection pump, an overflow subport 82 (hereinafter referred to as “subport 82”) is formed in the plunger barrel 80 in addition to a main port 81 serving as a fuel supply port, as shown in FIG. A structure having a mechanism for changing the injection timing by opening and closing by the advance angle actuator 85, that is, a low temperature start advance angle mechanism (hereinafter referred to as "CSD" (Cold Start Device)) is known ( For example, see Patent Document 1.) The CSD performs control to advance the start timing (injection timing) of fuel by the plunger 70 by closing the subport 82 at the time of starting, that is, advance angle control, thereby improving engine startability. ing. Further, in the CSD, an electromagnetic valve, a thermo element, or the like is used for the advance angle actuator 85 for closing the subport 82, and these are also disclosed in Patent Document 1.

  Moreover, as shown in FIG. 14, the structure which adjusts a fuel timing by providing various leads in the plunger 70 is also well-known (for example, refer patent document 2). In the configuration shown in FIG. 14, the plunger 70 is provided with the upper lead 71 in the right obliquely downward direction from the top of the plunger 70, and the lower lead 72 is also provided in the lower oblique direction below the upper lead 71. Yes. In addition, the inclination angle of the lower lead 72 is configured to be larger than the inclination angle of the upper lead 71, and the distance between the upper lead 71 and the lower lead 72 varies depending on the circumferential position of the plunger 70. . The plunger 70 configured in this manner is rotated by a governor device such as an electronic control governor in accordance with the pump rotation speed and the load, and the circumferential position of the plunger 70 with respect to the main port 81 is changed. As a result, the start timing (injection timing) of fuel pressure feeding and the period (fuel injection amount) during which the main port 81 is closed are changed.

  Further, in the configuration shown in FIG. 14, a sub-upper lead 73 is provided on the top of the plunger 70 so as to be displaced from the upper lead 71 in the circumferential direction. When the pump speed is low, the sub-upper lead 73 is provided. When the sub-port 82 is closed, fuel pumping is started.

  In FIG. 14, 81a, 81b, 81c, 81d indicate the pumping start position of the main port 81 to be changed according to the pump speed and load, and 81a is a high rotation and low load range. 81b corresponds to a low rotation and low load range, 81c corresponds to a high rotation and high load range, and 81d corresponds to a low rotation and high load range. Similarly, 82a, 82b, 82c, and 82d indicate the pumping start position of the subport 82 that is to be changed according to the pump speed and load, 82a is a high rotation and low load region, and 82b is low. The rotation and low load range, 82c corresponds to the high rotation and high load range, and 82d corresponds to the low rotation and high load range (for example, “during cold start”).

  In this configuration, the sliding speed of the plunger 70 is slow and the fuel tends to overflow from the subport 82d in a low rotation and high load range, so that the main port 81d is closed by the upper lead 71, and further, the sub upper portion When the sub port 82d is closed by the lead 73, the fuel pumping is started. For this reason, in particular, at the time of “low temperature start”, in order to improve the startability by accelerating the closing timing of the subport 82d, it is not necessary to wait for the subport 82d to be closed by the sub upper lead 73, and the CSD can I try to close it.

JP 2003-106240 A JP 2002-180929 A

  In the configuration of the conventional fuel injection pump described above, there are problems such as an increase in the number of parts and high cost, for example, it is necessary to mount an advance angle actuator such as a solenoid valve or a thermo element when adopting CSD. .

  On the other hand, in the conventional CSD, at the time of “low temperature start”, the timing for closing the subport 82d is advanced. However, the effective stroke for compression increases abruptly as the timing for closing the subport 82d is advanced. As shown in the increase amount Q shown in FIG. 2, the injection amount is greatly increased. For this reason, there is a problem that the combustion chamber cools due to a large increase in the injection amount, and on the contrary, the low-temperature startability deteriorates or the generation of black smoke increases.

  Accordingly, in view of the above problems, the present invention can control the injection timing in the same manner as CSD without providing an advance angle actuator, and suppress the increase in the injection amount at “low temperature start”. The configuration of the injection pump is proposed.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

In claim 1, an upper lead (7a) is provided on the top of the plunger (7) in a diagonally lower right direction, and is below the upper lead (7a) and on the peripheral surface of the plunger (7). The lower lead (7b) is provided in the right oblique downward direction, and the upper lead (7a) and the lower lead (7b) are provided at positions facing the main port (21) provided in the plunger barrel (8), A vertical groove (7c) is formed from the upper surface of the plunger (7) toward the lower lead (7b), and the top of the plunger (7) is shifted in the circumferential direction from the upper lead (7a), A sub-upper lead (7d) is provided facing diagonally downward to the right, and a starting lead (7f) is provided on the top of the plunger (7) to the right of the sub-upper lead (7d). (7f) is the end of the top of the plunger (7) That is, the sub upper lead (7d) and the start lead (7f) are formed at the edge between the upper end surface and the peripheral surface of the plunger (7), and the overflow subport (22) provided in the plunger barrel (8). ), And at the periphery of the plunger (7), below the upper lead (7a) and to the right of the lower lead (7b) is a start injection amount adjustment lead (7u) to the right. The start injection amount adjustment lead (7u) is formed by a groove (7n) communicating with the groove (7m) forming the lower lead (7b). The upper left end portion of the lead (7u) is disposed at a position higher than the lower right end surface of the lower lead (7b), and the start lead (7f) against the closure of the overflow subport (22) at the time of start. ) Of the main port (21) Relative release is to use the starting time injection amount adjustment leads (7u).

In claim 2, an upper lead (7a) is provided on the top of the plunger (7) in a direction obliquely downward to the right, and below the upper lead (7a) and on the peripheral surface of the plunger (7). The lower lead (7b) is provided in the right oblique downward direction, and the upper lead (7a) and the lower lead (7b) are provided at positions facing the main port (21) provided in the plunger barrel (8), A vertical groove (7c) is formed from the upper surface of the plunger (7) toward the lower lead (7b), and the top of the plunger (7) is shifted in the circumferential direction from the upper lead (7a), A sub-upper lead (7d) is provided facing diagonally downward to the right, and a starting lead (7f) is provided on the top of the plunger (7) to the right of the sub-upper lead (7d). (7f) is the end of the top of the plunger (7) That is, the sub upper lead (7d) and the start lead (7f) are formed at the edge between the upper end surface and the peripheral surface of the plunger (7), and the overflow subport (22) provided in the plunger barrel (8). ), And a start injection amount adjustment lead (7uA) is provided below the start lead (7f). The start injection amount adjustment lead (7uA) is provided below the start lead (7f). The groove (7p) is formed in the circumferential surface of the plunger (7) of the plunger (7) toward the lower right direction, and the groove (7p) communicates with the longitudinal groove (3c). The start lead (7f) is used for closing the subport (22), and the start injection amount adjusting lead (7uA) is also used for opening the overflow subport (22) .

  As effects of the present invention, the following effects can be obtained.

According to the first aspect of the present invention , the upper lead (7a) is provided on the top of the plunger (7) so as to be directed diagonally downward to the right, and is below the upper lead (7a) and around the plunger (7). On the surface, a lower lead (7b) is provided in a right obliquely downward direction, and the upper lead (7a) and the lower lead (7b) are opposed to a main port (21) provided in the plunger barrel (8). A vertical groove (7c) is formed from the upper surface of the plunger (7) toward the lower lead (7b), and the top of the plunger (7) is positioned circumferentially with the upper lead (7a). The sub upper lead (7d) is provided in the right obliquely downward direction, and the start lead (7f) is provided on the top of the plunger (7) to the right of the sub upper lead (7d). The starting lead (7f) is the top of the plunger (7). The sub upper lead (7d) and the start lead (7f) are formed at the end surface of the plunger (7), that is, at the edge between the upper end surface and the peripheral surface of the plunger (7). (22) is provided at a position opposite to the upper lead (7a) on the peripheral surface of the plunger (7) and to the right of the lower lead (7b). The starting injection amount adjustment lead (7u) is formed by a groove (7n) communicating with the groove (7m) forming the lower lead (7b), and the starting injection is performed. The upper left end portion of the quantity adjusting lead (7u) is disposed at a position higher than the lower right end surface of the lower lead (7b), and the starting lead is closed against the closing of the overflow subport (22) at the time of starting. (7f) and the main port (2 Against opening of), because it uses the startup time injection amount adjustment leads (7u), at the time of start-up, together with improved start time early in startability of pumping at the start leads, starting time injection amount By using the adjustment lead, the fuel pumping end time is advanced to prevent a significant increase in the injection amount.
Further, in the present invention, the advance timing actuator required for the conventional CSD is not provided, and the injection timing control similar to the CSD can be performed, so that the number of parts can be reduced and the cost can be reduced.

In the second aspect of the present invention , the upper lead (7a) is provided on the top of the plunger (7) so as to be directed diagonally downward to the right, and is located below the upper lead (7a) and around the plunger (7). On the surface, a lower lead (7b) is provided in a right obliquely downward direction, and the upper lead (7a) and the lower lead (7b) are opposed to a main port (21) provided in the plunger barrel (8). A vertical groove (7c) is formed from the upper surface of the plunger (7) toward the lower lead (7b), and the top of the plunger (7) is positioned circumferentially with the upper lead (7a). The sub upper lead (7d) is provided in the right obliquely downward direction, and the start lead (7f) is provided on the top of the plunger (7) to the right of the sub upper lead (7d). The starting lead (7f) is the top of the plunger (7). The sub upper lead (7d) and the start lead (7f) are formed at the end surface of the plunger (7), that is, at the edge between the upper end surface and the peripheral surface of the plunger (7). (22) is provided at a position opposite to the start lead (7f), and a start injection amount adjustment lead (7uA) is provided below the start lead (7f). The start injection amount adjustment lead (7uA) Is formed by a groove (7p) provided on the peripheral surface of the plunger (7) in the lower right direction, and the groove (7p) communicates with the longitudinal groove (3c). The start lead (7f) is used for closing the overflow subport (22), and the start injection amount adjustment lead (7uA) is also used for opening the overflow subport (22) . During start-up, pumping is performed with the start lead. With a start timing earlier by improving the startability, by advancing the end timing of the delivery of pressurized fuel by starting injection quantity adjustment lead, thereby preventing a significant increase in the injection quantity.
Further, in the present invention, the advance timing actuator required for the conventional CSD is not provided, and the injection timing control similar to the CSD can be performed, so that the number of parts can be reduced and the cost can be reduced.
Furthermore, in the present invention, the stroke (operation amount) of the control rack can be minimized, and the fuel injection pump as a whole can be reduced in size.

  The start lead is provided at the top of the plunger for the purpose of controlling the injection timing in the same way as CSD without the advance angle actuator and suppressing the increase in the injection amount at “low temperature start”. The start lead closes the sub-port provided in the plunger barrel and starts to pump fuel. The start injection amount adjustment lead is provided on the peripheral surface of the plunger, and at the start, the start injection amount adjustment lead is provided. This is achieved by opening the main port provided in the plunger barrel and terminating the fuel pumping.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a partial cross-sectional side view showing a configuration around a plunger in the first embodiment, and FIG. 2 is a development view of the plunger in the first embodiment.

  FIG. 3 is a block diagram of an apparatus related to the rotation control of the plunger, FIG. 4 is a diagram showing the relationship between the pump rotation speed and the injection timing, and FIG. 5 is a diagram showing the relationship between the pump rotation speed and the injection amount.

  FIG. 6 is a development view of the plunger in the second embodiment, FIG. 7 is a view showing the relationship between the pump speed and the control rack position, and FIG. 8 is a view showing effective strokes for the start lead and the sub upper lead.

  9A is a diagram showing the relationship between the pump rotation speed and the injection amount, FIG. 9B is a diagram showing the relationship between the rack position and the pump rotation speed, and FIG. 9C is the injection timing and the pump rotation. It is a figure which shows the relationship of a number.

  FIG. 10 is a view showing an embodiment in which a thermo element is applied to a mechanical governor, and FIG. 11 is a front view showing the structure of the thermo element.

  FIG. 12A is a diagram showing the state of the thermo element during the warm start, and FIG. 12B is a diagram showing the state of the thermo element during the low temperature start.

  13 is a partial cross-sectional side view showing a configuration around a conventional CSD, FIG. 14 is a developed view of a plunger showing the arrangement of a conventional lead, and FIG. 15 is a pump rotation speed and injection in a configuration including a conventional CSD. It is a figure which shows the relationship of quantity.

  In the following description, the left side in FIG. 2 is the left side, and the right side is the right side.

  In the first embodiment, as shown in FIGS. 1 and 2, the overflow subport 22 provided on the plunger barrel 8 is closed by the start lead 7f provided on the top of the plunger 7 at the time of start. For adjustment of the injection amount, a dedicated start injection amount adjustment lead 7u corresponding to the start lead 7f is provided.

  Hereinafter, the configuration of the first embodiment will be described in detail. As shown in FIG. 1, the plunger 7 slides up and down in the plunger barrel 8, and the plunger barrel 8 is formed with a main port 21 serving as a fuel supply port and a sub-port 22 for overflowing fuel. In FIG. 2, the peripheral surface of the plunger 7 is shown expanded, and the position corresponding to the fuel pumping start position for each of the main port 21 and the subport 22 provided in the plunger barrel is set for each pump rotation speed and load. It represents. Regarding the main port 21, respectively, 21a is a high rotation and low load range (at high idle), 21b is a low rotation and low load range (at low idle), 21c is a high rotation and high load range (at rated time), and 21d is The pumping start position in the case of low rotation and high load range (at start-up) is shown. Similarly, regarding the sub-ports 22, 22 a is a high rotation and low load range (at high idle), 22 b is a low rotation and low load range (at low idle), 22 c is a high rotation and high load range (at rated time), Reference numeral 22d denotes a pumping start position in the case of a low rotation and a high load range (at the time of starting).

  Further, as shown in FIG. 3, the plunger 7 is rotated by the operation of the control rack 3 by the governor device 2, and as described above, the main port 21, the sub port 22 and the plunger according to the rotation speed and the load. 7 is changed. In the first embodiment, the configuration of the governor device 2 is not particularly limited, and an electronic control type controlled by the controller 1 or a mechanical configuration without the controller 1 can be adopted.

  In FIG. 2, an upper lead 7 a is provided on the top of the plunger 7 in a diagonally downward direction to the right, and the lower lead 7 b is located on the peripheral surface of the plunger 7 below the upper lead 7 a. It is provided obliquely downward. These upper lead 7 a and lower lead 7 b are formed by carving a groove in the plunger 7. Further, a vertical groove 7c is formed from the upper surface of the plunger 7 toward the lower lead 7b. The upper lead 7a and the lower lead 7b are provided at positions facing the main port 21 provided in the plunger barrel. In the first embodiment, the lower lead 7b is used at the time of high idle, low idle, and rated. With this configuration, when the plunger 7 is raised, the main port 21 starts to close by the upper lead 7a, and when the main port 21 is completely closed, fuel feeding is started. Further, when the plunger 7 moves up, the main port 21 (21a, 21b, 21c) starts to open by the lower lead 7b, and high-pressure fuel in the fuel pressure chamber above the plunger 7 overflows into the main port 21 through the vertical groove 7c. Thus, the fuel pumping is completed.

  A sub-upper lead 7d is provided on the top of the plunger 7 in a diagonally downward right direction with a position shifted in the circumferential direction with respect to the upper lead 7a. The sub upper lead 7d is carved on the top of the plunger 7. The sub upper lead 7d is provided at a position facing the sub port 22 provided in the plunger barrel. In the first embodiment, the sub-upper lead 7d is used during low idle. With this configuration, when the pump speed is low and the load is low, the plunger 7 has a low sliding speed and the fuel from the subport 22b tends to overflow. After 22b begins to close, fuel pumping starts when the subport 22b is completely closed. As described above, the sub-upper lead 7d delays the start timing of fuel pumping, that is, retards control when the pump idling is low and the load is low.

  A starting lead 7f is provided on the top of the plunger 7 on the right side of the sub upper lead 7d. The starting lead 7f is formed at the top end surface of the plunger 7, that is, the edge between the upper end surface of the plunger 7 and the peripheral surface. In the first embodiment, the starting lead 7f is used at the time of starting. With this configuration, at the time of starting with a low pump speed and a high load, the subport 22d starts to close by the start lead 7f. The start lead 7f is arranged above the sub upper lead 7d, and at the start, the start timing of fuel pumping is advanced compared to the low idling, that is, the advance angle control is performed. To be done.

  In addition, a start-time injection amount adjustment lead 7u is provided in the diagonally lower right direction below the upper lead 7a on the peripheral surface of the plunger 7 and to the right of the lower lead 7b. The starting injection amount adjusting lead 7u is formed by a groove 7n communicating with the groove 7m forming the lower lead 7b. Further, the upper left end portion of the starting injection amount adjustment lead 7u is disposed at a position higher than the lower right end surface of the lower lead 7b. In the first embodiment, the starting injection amount adjusting lead 7u is used at the time of starting. With this configuration, the main port 21d starts to be opened by the starting injection amount adjustment lead 7u at the time of starting with a low pump speed and a high load. Since the upper left end portion of the starting injection amount adjusting lead 7u is arranged at a position higher than the right lower end surface of the lower lead 7b, the lower lead 7b is extended in the diagonally downward direction to the main port 21d. The main port 21d starts to open at an early stage as compared with the configuration in which the fuel pumping is terminated by opening the. As described above, the start injection amount adjustment lead 7u can advance the timing at which the main port 21d starts to open, that is, the end timing of fuel pumping.

  As described above, the start lead 7f is provided on the top of the plunger 7, and at the time of start, the subport 22 provided in the plunger barrel 8 is closed by the start lead 7f to start the fuel pumping. The start injection amount adjustment lead 7u is provided on the peripheral surface, and at the time of start, the main port 21 provided in the plunger barrel 8 is opened by the start injection amount adjustment lead 7u to finish the fuel pressure feed. .

  With the above configuration, as shown in FIG. 4, at the time of starting, the start lead 7f is used, so that the injection timing can be advanced (advanced), and startability can be improved. Further, as shown in FIG. 5, at the time of start-up, the start-up injection amount adjustment lead 7u is used, so that the start-up timing of pumping is advanced by the start-up lead 7f, but the start-up injection amount adjustment lead. By 7u, the fuel pumping end time is advanced, so that the injection amount can always be kept at a certain level, and the combustion chamber is cooled by a large increase in the injection amount, and the generation of black smoke is increased. The occurrence of defects can be prevented.

  In the second embodiment, as shown in FIG. 6, instead of providing the starting injection amount adjusting lead 7u below the upper lead 7a, a starting injection amount adjusting lead 7uA is provided below the starting lead 7f. It is what. The start-time injection amount adjustment lead 7uA is provided on the peripheral surface of the plunger 7 below the start lead 7f in a diagonally rightward direction, and is formed by a groove 7p. The groove 7p communicates with the vertical groove 3c.

  As described above, the start lead 7f is provided on the top of the plunger 7, and at the time of start, the subport 22 provided in the plunger barrel 8 is closed by the start lead 7f to start the fuel pumping. The starting injection amount adjustment lead 7u is provided on the peripheral surface, and at the time of starting, the sub-port 22 is opened by the starting injection amount adjustment lead 7u to finish the fuel pressure feed.

  With the above configuration, as shown in FIG. 4, at the time of starting, the start lead 7f is used, so that the injection timing can be advanced (advanced), and startability can be improved. In addition, at the time of starting, when the subport 22d is opened by the starting injection amount adjustment lead 7uA, the fuel pumping ends. By providing the starting injection amount adjusting lead 7uA, the fuel pumping ends. The time can be advanced. In this way, while the start timing of pumping is advanced by the start lead 7f, the injection end timing of fuel is advanced by the start injection amount adjustment lead 7uA, so that the injection amount is always kept at a constant level. It is possible to prevent the occurrence of problems such as cooling the combustion chamber due to a large increase in the injection amount and an increase in the generation of black smoke.

  Further, by providing the start injection amount adjustment lead 7uA on the start lead 7f side as described above, when switching from the start to another low idle, high idle, or rated time, that is, when switching the lead to be used. The stroke (operation amount) of the control rack 3 can be minimized. In the case where the starting injection amount adjustment lead 7u is provided on the upper lead 7a side as in the first embodiment, it is necessary to rotate the plunger 7 by the diameter of the main port 21d. In this case, the switching can be performed by rotating the plunger 7 by the diameter of the subport 22d. As described above, by minimizing the stroke (operation amount) of the control rack 3, the fuel injection pump as a whole can be reduced in size.

  As shown in FIG. 7, conventionally, the injection amount is increased at the time of starting, and when the pump rotational speed reaches a certain value, the increase of the injection amount is terminated. Then, the rotational speed at which the increase in the injection amount is terminated is set as the starting injection amount end rotational speed M. When the starting injection amount end rotational speed M is reached, the position of the control rack 3 is adjusted by the governor device 2 (see FIG. 3). The injection timing is retarded (solid line 33) as shown in FIG. 4 (solid line 31), and the injection amount is reduced (solid line 32) as shown in FIG. However, if the position of the control rack 3 is changed when the pump rotational speed reaches the starting injection amount end rotational speed M in this way, the rotational speed corresponding to the accelerator instruction value (hereinafter referred to as “target rotational speed”). It takes a long time to reach up to (Nset), and there is a problem that the start-up of the engine is particularly bad at low temperature start. Therefore, in this third embodiment, in addition to the first and second embodiments described above, the following configuration is adopted in order to improve the engine start-up at the time of cold start.

  As shown in FIG. 3, the third embodiment employs an electronic control governor that controls the governor device 2 by the controller 1 and electronically controls the rotation of the plunger 7 via the control rack 3. In the controller 1, the governor device 2 is controlled by a program stored in advance, and the position of the control rack 3 is changed or held.

  FIG. 7 shows the position of the control rack 3 with respect to the pump rotation speed. Among these, the dotted line 34 shows the position of the control rack 3 at the time of low temperature start, and is started by the governor device 2 until the pump speed reaches the speed N just before the target speed Nset. It shows that the position of the control rack 3 at that time is held. Thus, the start lead 7f and the start-time injection amount adjustment lead 7u are used until the pump speed reaches the speed N immediately before the target speed Nset.

  Note that the rotational speed difference between the target rotational speed Nset and the rotational speed N, which means “immediately before”, is set in advance according to the temperature at the start of the program in addition to a predetermined value in the program. May be. For example, when the temperature is extremely low, the difference in rotation speed between the target rotation speed Nset and the rotation speed N is made smaller, that is, the rotation speed N is set to be close to the target rotation speed Nset. Even in such a case, such as ensuring a good start-up of the engine. Further, the position of the control rack 3 at the time of start-up is maintained until “just before” because when the target rotational speed Nset is reached, the control rack 3 is moved from the start-up position to the normal temperature (low idling time). This is because the position is changed to the position at the time of high idle and at the time of rating.

  In this way, as shown in FIG. 7, the position of the control rack 3 at the time of starting is maintained by the electronic control governor until the rotational speed N is reached at the time of low temperature starting (dotted line 34). As shown in FIG. 4, even after the engine is started, the early injection timing is maintained (dotted line 35), and the engine can be started up well. Further, as shown in FIG. 5, even after starting, a state where the injection amount is large is maintained (dotted line 36), and this also makes it possible to improve the engine startup.

  In the fourth embodiment, a sub upper lead 7d (see FIGS. 2 and 6) is provided on the top of the plunger 7, and at the time of low temperature start, the overflow subport is closed by the start lead 7f and fuel pumping is started. In addition, at the time of warm-up start, the sub-upper lead 7d closes the overflow sub-port and starts to pump fuel.

  As shown in FIG. 8, in the region D where the sub upper lead 7d and the start lead 7f are switched at the top of the plunger 7, the subport closing timing (cam lift) changes abruptly (characteristics). As a result, the effective stroke changes abruptly (see the characteristic line L2). For this reason, in the region D, a sudden increase / decrease in the injection amount occurs, and stable fuel injection cannot be performed, that is, the injection amount cannot be controlled. For example, the rack position Q is set at the low temperature start, the start using the start lead 7f (low temperature start area A2) is performed, the rack position P is set after the start, and the sub upper lead 7d (normal control area A3). When the normal operation using is performed, it passes through the uncontrollable area A1 in which the injection amount increases (that the area D of the plunger 7 is used). The increase causes a problem that black smoke increases. However, at the time of warm start, since the startability is good, there is no need to use the start lead 7f. That is, it can be said that there is no problem even if starting at the rack position P at the time of warm start. By starting at the rack position P in this way, since the subsequent rack position adjustment is performed only in the normal control area A3, injection is performed in the uncontrollable area A1 (area D of the plunger 7). There is no such thing. Therefore, as described above, at the time of warm start, the sub upper lead 7d is used instead of the start lead 7f.

  The following two are proposed as embodiments for carrying out the fourth embodiment. The first is due to the electronic control governor. In this case, a known electronic control governor is adopted in the governor device 2 shown in FIG. 3, and the position of the control rack 3 is changed by the electronic control governor. The electronic control governor is controlled by the controller 1. When an engine start command is input, the controller 1 determines whether the engine is in a low temperature state or a warm state based on a detection value of a temperature sensor (not shown). If it is determined that the temperature is low, the electronic control governor is operated to use the start lead 7f and the position of the control rack is set to the rack position Q in FIG. On the other hand, if it is determined that the engine is in the warm state, it is determined that the warm-up is started, and the electronic control governor is operated to use the sub upper lead 7d, and the position of the control rack is set to the rack position P in FIG. Set.

  As described above, since the sub upper lead 7d is used during the warm start, the lead switching between the start lead 7f and the sub upper lead 7d after the start is not performed, and black smoke increases due to the lead switching. Such a problem does not occur. (A) to (c) of FIG. 9 explain this. In (a), the injection amount is different at the low temperature start and the warm start, and is indicated by a dotted line at the low temperature start. In this way, the rotational speed increases and a temporary increase in the injection amount occurs when the lead is switched. However, this does not occur at the start of the warm state. In (b), for the rack position, the start lead 7f is used at the time of low temperature start (start lead area), and the sub upper lead 7d is used at the time of warm start (normal lead area). Show. Further, (c) shows that the advance timing is performed at the low temperature start but the advance angle is not performed at the warm start in the injection timing.

  The second is due to a mechanical governor (see FIG. 10). In the case of the electronic control governor described above, the rack position switching control is performed by the control of the controller 1, but in this example, a thermo element 30 as shown in FIGS. Thus, the position of the control rack 3 is changed. As shown in FIGS. 10 to 12, the governor lever 41 is linked to the control rack 3 via a link 42. Further, the thermo element 30 acts on the governor lever 41 to advance and retract the control rack 3 via the link 42. The thermo element 30 is fixed to the governor case 44. Further, the thermo element 30 is provided with a piston 31 that advances and retreats in a direction orthogonal to the advancing and retreating direction of the link 42, and the advancing and retreating operation of the piston 31 is performed by an actuator 32. The actuator 32 expands the piston 31 at the time of warm-up start (at the time of warm-up), and contracts the piston 31 at the time of low-temperature start (at the time of low temperature). The piston 31 includes a large diameter portion 31 a on the side close to the actuator 32 and a small diameter portion 31 b on the side far from the actuator 32. At the time of warm-up (at the time of warm-up), the large-diameter portion 31a is brought into contact with the contact portion 42a at the end of the link 42, so that the link 42 moves in the right direction, that is, in the injection amount decreasing direction. Then, the rack position P (see FIG. 8) is set, whereby the sub upper lead 7d is used. At the time of low temperature start (low temperature), the small diameter portion 31b is brought into contact with the contact portion 42a at the end of the link 42, so that the link 42 is moved in the left direction in the drawing, that is, the injection amount decreasing direction (see FIG. 12 (b)), the rack position P (see FIG. 8) is set.

  As described above, even in the configuration of the mechanical governor, the rack position can be set according to the temperature state. Further, the thermo element 30 does not require electrical control, and can be retrofitted to a fuel injection pump equipped with an existing mechanical governor.

  In the fifth embodiment, the position of the control rack set at the low temperature start and the warm start, that is, the rack position P and the rack position Q are configured to be changeable. The positional relationship between the start lead 7f and the sub upper lead 7d with respect to the sub port is adjusted to avoid problems such as inability to control the injection amount due to the use of the region D of the plunger 7 (see FIG. 8). In the configuration described in the fourth embodiment, the following two are proposed as modes for embodying the fifth embodiment. When the electronic control governor is used, the controller 1 stores the control information in which the rack position P and the rack position Q corresponding to the temperature state are mapped, and the control information can be changed. It becomes.

  On the other hand, with respect to the mechanical governor, in the thermo element 30, the actuator 32 having a circular cross section is rotatably inserted into the governor case 44, and the bolt 36 is inserted into the base 35 of the actuator 32 through an arc-shaped long hole 35 a. The structure is fixed by The center position 32c of the actuator 32 and the center position 31c of the piston 31 are arranged eccentrically. As described above, the position of the piston 31 can be moved in the left-right direction in the figure by loosening the bolt 36 and rotating the base 35 as necessary. The lead 7d can be changed.

  The present invention is applicable to a fuel injection pump in which an overflow subport is formed in the plunger barrel and the injection timing is adjusted by opening and closing the overflow subport. In addition, in a fuel injection pump having a conventional CSD, by applying the present invention, it is possible to adopt a configuration in which an advance angle actuator such as a solenoid valve or a thermo element is omitted.

  Further, since the sub upper lead is used at the time of warm start, the lead is not switched between the start lead and the sub upper lead after the start, and there is a problem that black smoke increases due to the lead switching. There is nothing. In addition, even after starting, the early injection timing is maintained, and the engine can be started well. Further, even after starting, the state where the injection amount is large is maintained, and this also makes it possible to improve the engine startup. Also, in the configuration of the mechanical governor, the rack position can be set according to the temperature state.

  Further, according to the thermo element, it is not necessary to perform electrical control, and it is possible to retrofit it to a fuel injection pump equipped with an existing mechanical governor. In addition, the positional relationship between the start lead and the sub upper lead with respect to the sub port can be adjusted to avoid such a problem that the injection amount cannot be controlled.

It is a side surface partial sectional view which shows the structure of the periphery of the plunger in Example 1. FIG. It is an expanded view of the plunger in Example 1. FIG. It is a block diagram of the apparatus regarding rotation control of a plunger. It is a figure which shows the relationship between pump rotation speed and injection timing. It is a figure which shows the relationship between pump rotation speed and injection quantity. It is an expanded view of the plunger in Example 2. FIG. It is a figure which shows the relationship between a pump rotation speed and a control rack position. It is a figure shown about the effective stroke with respect to each of a starting lead and a sub upper part lead. (A) is a figure which shows the relationship between pump rotation speed and injection quantity. (B) is a figure which shows the relationship between a rack position and pump rotation speed. (C) is a figure which shows the relationship between an injection timing and pump rotation speed. It is a figure shown about the Example formed by applying a thermo element to a mechanical governor. It is a front view similarly shown about the structure of a thermo element. (A) is a figure which shows the state of the thermo element at the time of a warm start. (B) is a figure which shows the state of the thermo element at the time of a cold start. It is side surface partial sectional drawing which shows the structure of the periphery of the conventional CSD. It is an expanded view of the plunger shown about arrangement | positioning of the conventional lead | read | reed. It is a figure which shows the relationship between the pump rotation speed and injection quantity in a structure provided with the conventional CSD.

Explanation of symbols

7 Plunger 7a Upper lead 7b Lower lead 7f Start lead 7u Injection amount adjustment lead at start 21 Main port 22 Sub port

Claims (2)

An upper lead (7a) is provided on the top of the plunger (7) so as to be inclined downward to the right. The lower lead (7b) is provided below the upper lead (7a) and on the peripheral surface of the plunger (7). The upper lead (7a) and the lower lead (7b) are provided at positions facing the main port (21) provided in the plunger barrel (8), and the plunger (7) A vertical groove (7c) is formed from the upper surface toward the lower lead (7b), and the top portion of the plunger (7) is displaced in the circumferential direction from the upper lead (7a), so that the sub upper lead (7d) And a starting lead (7f) is provided on the top of the plunger (7) to the right of the sub-upper lead (7d). The starting lead (7f) (7) Top end face, that is, plunger 7) formed at the edge between the upper end surface and the peripheral surface, and the sub upper lead (7d) and the starting lead (7f) are opposed to the overflow subport (22) provided in the plunger barrel (8). The start injection amount adjustment lead (7u) is directed diagonally downward to the right below the upper lead (7a) on the peripheral surface of the plunger (7) and to the right of the lower lead (7b). The starting injection amount adjusting lead (7u) is formed by a groove (7n) communicating with the groove (7m) forming the lower lead (7b), and the starting injection amount adjusting lead (7u) The upper left end is disposed at a position higher than the lower right end surface of the lower lead (7b), and at the time of starting, the start lead (7f) is used for closing the overflow subport (22), When the main port (21) is opened, the start Fuel injection pump, characterized by the use of injection quantity adjustment lead (7u). An upper lead (7a) is provided on the top of the plunger (7) so as to be inclined downward to the right. The lower lead (7b) is provided below the upper lead (7a) and on the peripheral surface of the plunger (7). The upper lead (7a) and the lower lead (7b) are provided at positions facing the main port (21) provided in the plunger barrel (8), and the plunger (7) A vertical groove (7c) is formed from the upper surface toward the lower lead (7b), and the top portion of the plunger (7) is displaced in the circumferential direction from the upper lead (7a), so that the sub upper lead (7d) And a starting lead (7f) is provided on the top of the plunger (7) to the right of the sub-upper lead (7d). The starting lead (7f) (7) Top end face, that is, plunger 7) formed at the edge between the upper end surface and the peripheral surface, and the sub upper lead (7d) and the starting lead (7f) are opposed to the overflow subport (22) provided in the plunger barrel (8). The start injection amount adjustment lead (7uA) is provided below the start lead (7f), and the start injection amount adjustment lead (7uA) is a plunger (7) below the start lead (7f). The groove (7p) is formed in the circumferential surface of the outer peripheral surface of the subflow port (22) at the time of starting and communicates with the vertical groove (3c). A fuel injection pump characterized in that the start lead (7f) is used for closing and the start time injection amount adjusting lead (7uA) is used for opening the overflow subport (22) .

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