Governor device of diesel engine

Abstract: In a governor device of a diesel engine, a control rack (11) of a fuel injection pump (2) is adapted to be controllably actuated by a balance between a governor spring (24) and an engine revolution speed detecting actuation means (19). A speed control member (39) is adapted to be manipulated for adjusting a tension force of the governor spring (24). A fuel limiting actuation member (51) serves to prevent an excessive fuel from being injected in the case that the speed control member (39) is manipulated for a quick acceleration. A quick acceleration state detecting means (54) serves to detect a quickly accelerated state of the engine (1) so as to change over the fuel limiting actuation member (51) to a fuel limiting position (X) and to a fuel limitation cancelling position (Y) depending on the lapse of time.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a governor device installed to a diesel engine, and more specifically to a governor device provided with a mechanical governor or a pneumatic governor. 2. Prior Art Generally, the aforementioned governor device is constructed as follows. A control rack of a fuel injection pump is adapted to be operatively controlled through a governor lever in accordance with a balance between a resilient force exerted to a fuel increasing side by a governor spring and a governor force exerted to a fuel decreasing side by an actuation member such as a governor weight and the like. Thereby, though a load of a diesel engine changes, an engine revolution speed can be maintained at a predetermined value. As such governor device, there has been known the one provided with two levers as a governor lever as disclosed in Japanese Utility Model Laid Open Publication No. 1987 -82345. This prior art was filed by an assignee of the present invention and is constructed as follows. That is, the governor lever comprises a fork lever to be engaged with the control rack and a spring lever actuated by a tension force of the governor spring. The spring lever is adapted to be received by a fuel limiting pin at the full load position, and the fork lever is adapted to be resiliently urged to the fuel increasing side by a starting spring. Since the aforementioned double-lever type governor device is capable of moving the control rack to a ptarting fuel increasing position by the starting spring through the fork lever, advantageously the engine can be readily started. There is, however, such a problem associated therewith, as black smoke is generated at the time of a quick acceleration of the engine. That is, when an acceleration lever and the like are quickly operated for a quick acceleration, the tension force of the governor spring is promptly increased. But, since there exists a time lag in an increase of the engine revolution speed, a balance between the governor force and the tension force of the spring is broken and then the spring lever and the fork lever are quickly swung to the fuel increasing side. Since the swing is quick, the fork lever is further swung to the fuel increasing side by both its inertial force and the tension force of the starting spring and to make the control rack overrun to the starting fuel increasing position even after the spring lever has been received by the fuel limiting pin. Thereby, a fuel injection quantity of the fuel injection pump becomes excessive to generate black smoke. Further, the problem of the smoke generated at the quick accelerating operation was caused also in a single-lever type governor device of a diesel engine with a turbocharger. That is, similarly to the above, the tension force of the governor spring is promptly increased by the quick accelerating operation of the acceleration lever and the like. But, there exists a time lag in the increase of the engine revolution speed as well as there also exists a time lag in an increase of a boost pressure of the turbocharger. Therefore, an excessive fuel is supplied relative to a less intake air to generate black smoke. SUMMARY OF THE INVENTION It is an object of the present invention to restrain a generation of black smoke even in the case that a diesel engine is quickly accelerated. JP-A-62159739 describes a system for restricting fuel injection at the start of acceleration. According to the present invention there is provided a governor device for a diesel engine having a fuel injection pump with a control rack resiliently urged to a fuel increasing side by a governor spring and to a fuel decreasing side in response to an input from an engine revolution speed detecting actuation means, the governor device comprising a speed control member that adjusts the tension force of the governor spring and which, when manipulated for quick acceleration, activates a fuel limiting actuation member to prevent excessive fuel injection, and quick acceleration state detecting means for detecting a position of an engine acceleration control element and operative to move the fuel limiting actuation member to a fuel limiting position for a predetermined time commencing at least from the time that quick engine acceleration is detected and, after lapse of said predetermined time, actuating the fuel limiting actuation member to move to a fuel limitation cancelling position, characterised in that an actuation rod of the fuel limiting actuation member is opposed to the control rack, the actuation rod being switchable over to the fuel limiting position or to the fuel limitation cancelling position and when a target value for a speed related parameter of the diesel engine exceeds a low speed range, said detecting means responds to generate an output to cause movement of the fuel limiting actuation member from the fuel limitation cancelling position to the fuel limiting position during said predetermined time, said detecting means being mounted in a speed control transmission system from the governor spring to an acceleration lever via the speed control member so as to make direct contact with said acceleration control element. According to the above-mentioned construction, the following advantages can be provided. When the diesel engine is operatively accelerated from its low revolution speed range, as mentioned above, a balance between the governor force and the tension force of the governor spring is broken and the control rack is apt to quickly shift to the fuel increasing side. Thereupon, the shifting farther than a predetermined distance is prevented for the required time by the fuel limiting actuation member changed over to the fuel limiting position. As a result, an excessive fuel is prevented from being injected into a combustion chamber of the diesel engine within the required time to restrain the generation of black smoke. Further, after the lapse of the aforementioned time, since the fuel limiting actuation member is changed over to the fuel limitation cancelling position, the control rack is allowed to shift to the fuel increasing side. But, at that time, the engine revolution speed has increased so that the governor force has become sufficiently large, and also the boost pressure has sufficiently increased even in the case of the engine with the turbocharger. Accordingly, even after the lapse of the required time, the fuel injection quantity can be prevented from becoming excessive, so that the generation of the black smoke can be restrained. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 through 6 show a first embodiment of the present invention; Figure 1 is a vertical sectional front view of a governor device; Figure 2 is a front view of a speed control member of the governor device; Figure 3 is a sectional view taken along the III - III directed line in Fig. 2; Figure 4 is an explanatory view of an operation of the governor device at the time of an engine start; Figure 5 is an explanatory view of the operation of the governor device under a low speed operating condition of the engine; Figure 6 shows changeover conditions of a fuel limiting actuation member, Figure 6(A) is a view showing a change of a target speed set by the speed control member relative to the lapse of time, and Figure 6(B) is a view showing a change of an actuation position of the fuel limiting actuation member relative to the lapse of time. DESCRIPTION OF THE PREFERRED EMBODIMENTS Figs. 1 through 6 show an embodiment of the present invention. Firstly, the whole construction thereof will be explained with reference to Figs. 1 through 3. As shown in Fig. 1, a diesel engine 1 has a pump housing 4 provided with a fuel injection pump 2 and a mechanical governor device 3. A gear case 5 is fixedly secured to the right side of the pump housing 4. The fuel injection pump 2 is inserted into the pump housing 4 from above the upper wall 4a of the pump housing 4 and fixedly secured to the upper wall 4a. A fuel injection camshaft 7 is rotatably supported by the pump housing 4 below the pump 2. A fuel injection cam gear 8 is fixedly secured to the right end of the camshaft 7. This cam gear 8 is interlockingly connected to a crankshaft ( not illustrated ). Four cams 9 mounted onto the camshaft 7 are brought into contact with respective pump element input portions 10 of the pump 2. A control rack 11 is internally fitted in the halfway height portion of the pump 2 so as to be shiftable in the right and left direction. A rack pin 12 is projected from the right portion of the control rack 11. In figures, the symbol R designates a fuel increasing side, and the symbol L does a fuel decreasing side. A mechanical governor 14 of the governor device 3 is constructed as follows. A governor shaft 15 is rotatably supported below the fuel injection camshaft 7 by the pump housing 4. A governor gear 16 fixedly secured to the right end of the governor shaft 15 is intermeshed with the cam gear 8. To the governor shaft 15, a weight holder 17 is fixedly secured and a governor sleeve 18 is externally fitted so as to be slidable in the right and left direction. A governor weight 19 as an engine revolution detecting actuation means is supported by the weight holder 17 so as to be centrifugally swingable. A centrifugal force of the governor weight 19 which varies as the engine revolution changes is transmitted to a rack pin 12 through the governor sleeve 18 and a sgovernor lever 20 in order. The governor lever 20 comprises a fork lever 23 engaged with the rack pin 12 and a spring lever 25 connected to the right end portion of a governor spring 24. The fork lever 23 and the spring lever 25 are swingably supported at their lower portions by the pump housing 4 through a lever pivot 26. A governor force F of the governor sleeve 18 acts on an input roller 27 disposed at the lower portion of the fork lever 23. The fork lever 23 and the spring lever 25 are interlocked by a torque spring 28 ( refer to Figs. 4 and 5 ). The control rack 11 is resiliently urged to the fuel increasing side R by the tension force 5 of the governor spring 24 through the spring lever 25 and the fork lever 23 in order. To the contrary, the control rack 11 is resiliently urged to the fuel decreasing side L by the governor force F through the fork lever 23. When the engine revolution changes as an engine load varies, the control rack 11 controls the fuel injection quantity of the fuel injection pump 2 in accordance with the balance between the spring tension force S and the governor force F so that the engine revolution speed can be returned to a set revolution speed. A fuel limiting pin 29 is fixedly secured to the upper wall 4a of the pump housing 4. The spring lever 25 is received by the fuel limiting pin 29 at a full load position B ( refer to Fig. 4 or Fig. 5 ) and further restrained from moving to the fuel increasing side R. The fork lever 23 comprises a vertically elongated lever body 31 and a thrust arm 32 horizontally slidably disposed at the upper portion of the lever body 31. The pin 12 of the control rack 11 is held between the upper portion of the lever body 31 and the right portion of the thrust arm 32 without any fitting gap. Thereby, a reactivity from the governor lever 20 to the rack pin 12 is increased. Between the left portion of the thrust arm 32 and a housing left wall 4c there is mounted a starting spring 33 for resiliently urging the control rack 11 to the fuel increasing side R. Further, between the right portion of the thrust arm 32 and the gear case 5 there is mounted an idle limit spring 34 for preventing the control rack 11 from moving to a fuel non-injection position. For setting the engine revolution speed, there is provided a means for adjusting the tension force S of the governor spring 24. This means will be explained with reference to Figs. 1 through 3. As shown mainly in Figs. 2 and 3, an inside cover plate 36 and an outside cover plate 37 are attached to a front wall 4b of the pump housing 4 in order, and a pin 38 is rotatably supported by the outside cover plate 37. A speed control member 39 is fixedly secured to the outer end portion of the pin 38, and a speed control arm 40 is fixedly secured to the inner end portion of the pin 38. The speed control member 39 is adapted to be manipulated within a swing-angular extent defined by a low speed limit bolt 42 and a high speed limit bolt 43, through a revolution limiting arm 41 fixedly secured to the pin 38. The lower portion of the speed control arm 40 and the left upper swinging portion of the spring lever 25 are connected by the governor spring 24. An engine stop lever 47 is fixedly secured to the outer end portion of another pin 46 rotatably supported by the outside cover plate 37, and a stopping arm 48 is fixedly secured to the inner end portion of the pin 46. When the engine is stopped, the stop lever 47 is turned clockwise so that the rack pin 12 is forcedly moved to the fuel decreasing side L by the stopping arm 48 through the governor lever 20 and then the control rack 11 is changed over to a stop position E ( refer to Fig. 4 or Fig. 5 ). Incidentally, the turning manipulation for the stop lever 47 is restrained by another limit bolt 49. In the governor device 3 constructed as mentioned above, there is provided a means for preventing the fuel from being excessively supplied in the case that the speed control member 39 is manipulated for the quick acceleration. That is, as shown in Fig. 1, a solenoid 51 as the fuel limitation actuating member is fixedly secured to the housing left wall 4c, and an actuation rod 52 of the solenoid 51 is opposed to the left end surface of the control rack 11. A limit switch 54 and an electronic timer as the quick acceleration state detecting means are arranged in series in a feed circuit 53 for the solenoid 51. Incidentally, the symbol 57 designates a battery, and the symbol 58 designates an engine key switch. The limit switch 54, as shown in Fig. 2, is fixedly secured to the left upper portion of the outside cover plate 37. A contact 60 of the limit switch 54 is opposed to the base portion of the speed control member 39. Under the condition that the speed control member 39 is manipulated to a low speed revolution range ( for sample, a low speed range not more than ab. 1200 rpm in the case that the rated revolution is 3000 rpm ), the contact 60 is resiliently urged by the speed control member 39 so that the limit switch 54 is held in the opened circuit state ( electrically non-communicated state, the same hereinafter ). Thereby, the solenoid 51 is held in the electrically non-communicated state so that the actuation rod 52 is held in a fuel limitation cancelling position Y. To the contrary, in the case that the speed control member 39 is manipulated to a position beyond the low speed revolution range, the contact 60 is projected so that the limit switch 54 is changed over to the closed circuit state ( electrically communicated state, the same hereinafter ). Thereby, an elctricity is fed to the solenoid 51 for a required time for example, around from 0.5 secs. to 1.0 sec. ) set by a timer 55 so that the actuation rod 52 is advanced to be changed over to the fuel limiting position X. After the lapse of the required time set by the timer 55, the solenoid 51 is returned to the electrically non-communicated state so that the actuation rod 52 is retreated to the fuel limitation cancelling position Y. The operation of the governor device 3 will be explained with reference to Figs. 4 through 6. Figs. 4 and 5 are explanatory views of the operation thereof schematically showing Fig. 1 respectively. In Fig. 6(A), the solid line M indicates a change of a target revolution speed to be set by the speed control member 39, and the alternate long and short dash line N indicates a change of the actual revolution speed of the engine. In Fig. 6(B), the solid line U indicates a change of the position of the actuation rod 52 of the fuel limiting solenoid 51, and the alternate long and two short dashes line W indicates a change of the positiori of the left end surface of the control rack 11. When the engine is started, as shown in Fig. 4, the speed control member 39 is manipulated to the starting position. Thereupon, the spring lever 25 is pulled to the fuel increasing side R by the governor spring 24 so as to be received by the fuel limiting pin 29 at the position corresponding to the full load position B. The fork lever 23 is further pulled by the starting spring 33 to the fuel increasing side R so as to move the the control rack 11 to the starting position D via the torque-up position C. By the way, though the limit switch 54 is in the closed circuit state, the timer 55 has already run down and the solenoid has gotten to the electrically non-communicated state. Therefore, the actuation rod 52 is held at the fuel limitation cancelling position Y by a retreating spring 51a so that the control rack 11 is allowed to move leftward. As shown in Fig. 5, at the time of thelow speed operation of the engine, the speed control member 39 is manipulated to the low speed revolution range indicated by the solid line view. Under this low speed operating condition, the control rack 11 is controlled through the governor lever 20 in accordance with the balance between the tension force S of the governor spring 24 and the governor force F of the governor weight 19. By the way, in the case that an overload is imposed to the engine, the torque-up spring 28 serves to resiliently urge the fork lever 23 to the fuel increasing side R so as to make the engine running tenacious. Further, since the contact 60 of the limit switch 54 is adapted to be pushed and retreated by the speed control member 39, the limit switch 54 is held in the opened circuit state. Thereby, the solenoid 51 is held in the electrically non-communicated state, and the actuation rod 52 is at the fuel limitation cancelling position Y similarly to the above. Then, when the speed control member 39 is manipulated for the quick acceleration from the aforementioned low speed revolution range ( refer to the alternate long and two short dashes line in Fig. 5 and the time t1 in Fig. 6 ), the tension force S of the governor spring 24 promptly increases and to the contrary, the increase of the engine revolution speed delays. Therefore, the balance between the governor force F and the spring tension force S is broken, so that the spring lever 25 and the fork lever 23 are quickly swung to the fuel increasing side R. Since the swinging is quick, the fork lever 23 is further swung to the fuel increasing side R by the leftward inertial force and the tension force of the starting spring 33 even after the spring lever 25 has been received by the fuel limiting pin 29. Thereupon, the control rack 11 is forced so as to overrun to the left side outside the torque-up position C. However, since the speed control member 39 gets out of the low speed revolution range and the limit switch 54 gets to the electrically communicated state prior to the leftward smovement of the the control rack 11, the actuation rod 52 is changed over to the fuel limiting position X during the required time T1 ( around from 0.5 secs. to 1.0 sec. ) set by the timer 55. Therefore, the control rack 11 is prevented from overrunning to the fuel increasing side R beyond the torque-up position C during the required time T1. As a result, it can be prevented that an excessive fuel is injected into the combustion chamber of the engine as well as the generation of the black smoke can be restrained. After the time t2 past the required time T1, since the solenoid 51 is changed over to the electrically non-communicated state, the actuation rod 52 is changed over to the fuel limitation cancelling position Y to allow the control rack 11 to move to the fuel increasing side R. But, at that time, since the engine revolution speed has increased and the governor force F has become sufficiently large, it can be restrained that the fuel injection quantity becomes excessive. Incidentally, the position for preventing the overrun of the control rack 11 by the actuation rod 52 may be set to the fuel decreasing side L beyond the torque-up position C or the full load position B. Further, the aforementioned limit switch 54 may be disposed in a speed control transmission system from the governor spring 24 to an acceleration lever ( not illustrated ) via the speed control member 39. Accordingly, the limit switch 54 may be so disposed as to be opposed to the revolution limiting arm 41 interlocked to the speed control member 39, the speed control arm 40, and the acceleration lever and so on. Furthermore, the quick acceleration state detecting means may be an acceleration detecting switch instead of the limit switch. Instead that the fuel limiting solenoid 51 and the engine stop lever 47 are separately provided, the fuel limiting solenoid may comprise a double-acting solenoid so that the engine can be stopped by making use, of the solenoid. Further, there may be provided a hydraulic cylinder adapted to be driven by means of a hydraulic pressure delivered from an engine lubrication oil feed pump as well as the fuel limiting actuation member may comprise this hydraulic cylinder and a stop valve. Thereupon, the quick acceleration state detecting means may be composed of an engine revolution speed detecting means ( for example, an intake negative pressure detecting means, an alternator voltage detecting means, a means for detecting a revolution speed of a ring gear connected to the crankshaft and the like ). When the engine revolution speed exceeds the low speed revolution range, the hydraulic cylinder is advanced to the fuel limiting position by opening the stop valve depending on that detection signal. Incidentally, the aforementioned solenoid 51 may be so constructed as to be actuated by the engine revolution speed detecting means. The governor device may comprise a pneumatic governor instead of the mechanical governor. In this case, the engine revolution speed detecting actuation means is composed of a diaphragm type cylinder to be actuated by the intake negative pressure instead of the governor weight.

Claims: A governor device for a diesel engine (1) having a fuel injection pump (2) with a control rack (11) resiliently urged to a fuel increasing side (R) by a governor spring (24) and to a fuel decreasing side (L) in response to an input from an engine revolution speed detecting actuation means (19), the governor device comprising an engine speed control member (39) that adjusts the tension force of the governor spring (24) and which, when manipulated for quick acceleration, activates a fuel limiting actuation member (51) to prevent excessive fuel injection, and quick acceleration state detecting means (54) for detecting a position of an engine acceleration control element and operative to move the fuel limiting actuation member (51) to a fuel limiting position (X) for a predetermined time (T1) commencing at least from the time that quick engine acceleration is detected and, after lapse of said predetermined time, actuating the fuel limiting actuation member (51) to move to a fuel limitation cancelling position (Y), characterised in that an actuation rod (52) of the fuel limiting actuation member (51) is opposed to the control rack (11), the actuation rod (52) being switchable over to the fuel limiting position (X) or to the fuel limitation cancelling position (Y); in that a quick acceleration is detected when the position of said acceleration control element indicates a target value for the engine speed exceeding a low speed range, whereupon said detecting means (54) responds to generate an output to cause movement of the fuel limiting actuation member (51) from the fuel limitation cancelling position (Y) to the fuel limiting position (X) during said predetermined time (T1), said detecting means (54) being mounted in a speed control transmission system from the governor spring (24) to an acceleration lever via the speed control member (39) so as to make direct contact with said acceleration control element. A governor device as defined in claim 1, wherein said control rack (11) is resiliently urged to the fuel increasing side (R) by the governor spring (24) through a fork lever (23) and a spring lever (25), in that order and pushed to the fuel decreasing side (L) by the engine revolution speed detecting actuation means (19) through the fork lever (23), said spring lever (25) is adapted to be received by a fuel limiting pin (29) at the full load position (B), and said fork lever (23) is adapted to be resiliently urged to the fuel increasing side (R) by a starting spring (33). A governor device as defined in claim 1, wherein said diesel engine (1) is equipped with a turbocharger. A governor device as defined in claim 1, wherein said quick acceleration state detecting means (54) is attached to the speed control member (39).

Inventors: MORIOKA KAZUYOSHI, MURATA MUTSUMI, NAGAHAMA MASAHIRO, SHIRAISHI YASUNORI, UMEDA YUZO, YAMADA SETSUO, MORIOKA, KAZUYOSHI, MURATA, MUTSUMI, NAGAHAMA, MASAHIRO, SHIRAISHI, YASUNORI, UMEDA, YUZO, YAMADA, SETSUO
Applicants: KUBOTA KK, KUBOTA CORPORATION
Application year: 1990
Main classification: F02D1
IPC codes: F02D1, F02B3, F02M59