Fuel injection device of diesel engine

A fuel injection device of a diesel engine capable of smoothly starting the diesel engine to match an environment around the engine by saving fuel, reducing the exhaustion of carbon dioxide, and suppressing black smoke in starting the diesel engine. A rack is operated by an actuator from a lowest rack position to a starting increased fuel amount position at a lower speed than that at which the rack is operated by the actuator from the lowest rack position to the starting increased fuel amount position at the maximum operating speed. The operating speed of the rack is set in two stages, and the later operating speed of the rack is reduced less than the operating speed of the rack up to a set intermediate rack target value P2. Then, the operating amount of the rack per hour is reduced after the ignition of the engine is recognized. Also, the operating speed of the rack is controlled according to an atmospheric temperature in starting the engine.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a fuel injection device of a diesel engine and more particularly to a control system of a rack position by a governor.

2. Background Art

In starting the diesel engine, the amount of fuel injection is typically increased for the start ability by making a starting fuel amount position of the rack in the fuel injection pump shifted to an increased starting fuel amount position. Providing enough amount of fuel to the engine keeps the start ability without considering the environment of the engine.

FIG. 24typically illustrates a conventional starting process of the engine. It is operated in the order, (a), (b), and (c) inFIG. 24. The left part ofFIG. 24illustrates a situation of the fuel injection pump. The center part ofFIG. 24illustrates a situation of a starter motor32. The right part ofFIG. 24illustrates a relation between the rack position and the elapsed time.

As shown inFIG. 24, an electronic governor41controls the amount of fuel injection of the fuel injection pump34; in this case, the amount is zero until the engine starts. When the starting switch is turned on, the rack is operated to a starting increased fuel amount position and the starter motor cranks up the engine. The electronic governor operates the rack to the position before the starter motor finishes cranking, and enough amount of fuel corresponding to the starting increased fuel amount position is supplied to cylinders of the engine1.

Japanese patent application H5-321699 discloses, for example, that the electronic governor adjusts the amount of fuel injection according to the temperature of the engine oil.

However, the larger amount of fuel than the is sufficient is supplied to the engine when the starter motor cranks up the engine. Therefore, the fuel consumption becomes higher in starting the engine, and surplus fuel may cause black smoke.

In the art, enough amount of fuel for starting the engine is supplied at the beginning and the fuel supply tends to become higher, so that the fuel consumption for starting the engine becomes higher.

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

The objective of the invention is to propose a fuel injection device of a diesel engine capable of smoothly starting the engine to match an environment around the engine, of saving fuel, and of suppressing black smoke in starting the engine.

Means of Solving the Problems

According to the invention, this objective is achieved by the device as follows.

A first feature of the invention is that a fuel injection device of a diesel engine comprises a means for increasing fuel amount in starting the engine, said means for increasing fuel amount comprises a rack operated within an operating speed range in a starting increased fuel amount position from the lowest rack position, said operating speed range is slower than the maximum rack operating speed.

A second feature of the invention is that the rack is operated at two step speeds, a first speed to a configured rack position and a second speed slower than first, during the operation of the rack from the lowest rack position to a starting increased fuel amount position.

A third feature of the invention is that target positions of the rack at the elapsed time are configured as a plurality of stages during the operation of the rack from the lowest rack position to a starting increased fuel amount position.

A fourth feature of the invention is that a fuel injection device of a diesel engine comprises a means for increasing fuel amount and a means for recognizing the ignition of the engine in starting the engine, wherein said means for increasing fuel amount comprises a rack operated from the lowest rack position to a starting increased fuel amount position and operated for reducing displacement of the rack per time after the ignition of the engine is recognized.

A fifth feature of the invention is that the rack is operated to the starting increased fuel amount position at the maximum operating speed after a predetermined time.

A sixth feature of the invention is that the operating speed of the rack is changed according to a temperature in starting the engine.

A seventh feature of the invention is that the set intermediate rack target position is changed according to a temperature in starting the engine.

In the case that the fuel injection device comprises an electronic actuator, the invention is embodied as follows.

A fuel injection device of a diesel engine comprising a rack operated by the actuator and a means for increasing fuel amount in starting the engine, wherein the rack is operated from the lowest rack position to a starting increased fuel amount position at a lower speed than that at which the rack is operated from the lowest rack position to the starting increased fuel amount position at the maximum operating speed. As a result, it is possible to ignite the engine at a necessary rack position for starting the engine at the state of low or high temperature.

A fuel injection device of a diesel engine comprising a rack operated by the actuator and a means for increasing fuel amount in starting the engine, wherein the rack is operated from the lowest rack position to a starting increased fuel amount position at the operating speed of the rack set in two steps, and the later operating speed of the rack is reduced less than the operating speed up to a set intermediate rack target value. As a result, it is possible to shorten the time to ignite, and it is possible to suppress black smoke in starting the engine.

A fuel injection device of a diesel engine comprising a rack operated by the actuator and a means for increasing fuel amount in starting the engine, wherein the rack is operated according to rack target positions that are set in numerous steps according to elapsed time and the rack target value is selected. As a result, it is possible to surely suppress black smoke and to save fuel in starting the engine.

A fuel injection device of a diesel engine comprising a rack operated by the actuator and a means for increasing fuel amount in starting the engine, wherein the rack is operated from the lowest rack position to a starting increased fuel amount position, the operating speed of the rack is reduced after the ignition of the engine is recognized. As a result, it is possible to avoid surplus fuel supply to the engine after the ignition and to suppress black smoke in starting the engine.

The rack is operated to the starting increased fuel amount position at the maximum operating speed after a predetermined time passes. As a result, it is possible to smoothly start the engine even if the engine drives a work machine or the work machine gives many loads to the engine.

The set intermediate rack target value is set according to a temperature in starting the engine. As a result, it is possible to start the engine according to the condition of fuel, to save fuel, to suppress black smoke, and to shorten the time required to start.

The operating speed of the rack is controlled according to a temperature in starting the engine. As a result, it is possible to start the engine according to the condition of fuel and to shorten the time required to start.

Moreover, the fuel injection device comprising a mechanical governor is concretely configured as follows.

A fuel injection device of a diesel engine comprising a means for increasing fuel amount in starting the engine by means of the operation of the rack by a governor lever which is connected to the mechanical governor and operates the rack, wherein a resistance body is contacted to the governor lever in starting the engine, and the operating speed of the governor lever7to the starting increased fuel amount position is reduced. As a result, it is possible to ignite the engine at a necessary rack position for starting the engine from the state of low temperature to the state of high temperature.

The resistance body is contacted to the governor lever on the way to the starting increased fuel amount position. As a result, the operating speed is controllable on the way, and it is possible to suppress black smoke and to shorten the time required to start.

A damper device that comprises a casing installing a governor is contacted to the governor lever. As a result, it is possible to control the contacting position from the outside of the casing of the governor and to easily adjust.

The resistance body installs a temperature-sensitive element, so that the position where the resistance body is contacted to the governor lever is capable of being adjusted according to the temperature in starting the engine. As a result, it is possible to control the amount of fuel injection according to the temperature condition, and it is possible to suppress black smoke, and to shorten the time required to start.

In a fuel injection device of a diesel engine comprising a (CSD) and a means for increasing fuel amount in starting the engine by means of the operation of the rack, the position where the speed of the rack is changed is adjusted according to the condition of the CSD. As a result, it is possible to improve the engine start and suppress black smoke even in the fuel injection pump comprising the CSD.

In a fuel injection device of a diesel engine comprising a CSD and a means for increasing fuel amount in starting the engine by means of the operation of the rack, the operating speed of the rack is adjusted according to the condition of the CSD. As a result, it is possible to improve the engine start and suppress black smoke even in the fuel injection pump comprising the CSD.

EFFECT OF THE INVENTION

The fuel injection device of a diesel engine of the invention provides a diesel engine starting smoothly, matching an environment around the engine, saving fuel and suppressing black smoke in starting the engine.

An advantage is that the amount of hydrocarbon exhaust when the engine starts is reduced and black smoke is suppressed in starting the engine. A further advantage is that the amount of fuel required to start is reduced and that the response to the starting operation when the engine starts is improved. A still further advantage is that a smooth start is secured corresponding to the environment around the engine and that black smoke is suppressed.

DETAILED DESCRIPTION OF THE INVENTION

The Best Mode for Carrying Out the Invention

The invention is to improve the engine start by adjusting the operating speed of the rack in starting the engine.

First Embodiment

The preferred embodiment of the invention is as shown in the presentation below, making reference to the drawings.FIG. 1illustrates a sectional side view of the fuel injection device according to the invention.

In an especially preferred embodiment of the invention, the device is configured as an engine1, a starter motor32which helps to start the engine, a controller31, a start switch36, a fuel injection pump34, and a pick up sensor37which recognizes the engine condition.

The engine1comprises the starter motor32, the fuel injection pump34, the pick up sensor37, and a thermo sensor33. The starter motor32drives a crankshaft of the engine in starting the engine. The fuel injection pump34is controlled by the controller31, which measures the speed of revolution of the engine1and controls the fuel injection pump34on the basis of a map stored in the controller31and relating the revolution of the engine to the amount of fuel injection.

The fuel injection pump34compresses and supplies fuel synchronizing with the revolution of the crankshaft, and is controlled by the electronic governor (comprised in the fuel injection pump34). The pick up sensor37measures the speed of revolution of the crankshaft, and recognizes the situation of cranking or of driving. The thermo sensor33measures the temperature of the cooling water of the engine1.

The controller31is connected to the start switch36, the fuel injection pump34, the pick up sensor37, and the thermo sensor33. The controller31can recognize whether the start switch36is turned on or off, and can detect the speed of revolution of the crankshaft. And the controller31can control the fuel injection pump34. The start switch36is for driving the engine1or for stopping the engine1, and the start switch36has three positions, “ON (driving)”, “OFF (stopped)”, “START (cranking).” The start switch36is set to the ‘START’ position, and the starter motor32is driven and the cranking (starting the engine) is begun. The start switch36is returned automatically from ‘START’ position to ‘ON’ position, so that the start switch36remains at ‘ON’ position after the engine is started and the engine1is kept driving. The thermo sensor33allows the controller31to recognize the temperature of the cooling water of the engine1. The controller31detects the period that the start switch36is kept at ‘START’ position. And the starter motor32is driven during that period.

The fuel injection pump is described below.FIG. 2illustrates partly sectional side view of fuel injection device.

The fuel injection pump34compresses and supplies fuel synchronizing with the revolution of the crankshaft of the engine1. The electronic governor41electronically controls the amount of fuel injection that is compressed and supplied. The fuel injection pump34comprises the electronic governor41, a plunger42, a sleeve44, a pinion43, and a rack45. The plunger42slides up and down in the sleeve44synchronizing with the revolution of the crankshaft. The sleeve44is fixed in the casing of the fuel injection pump34, and is comprised with a port as an outlet of fuel.

The plunger42comprises a spiral groove. The relation between a position of the groove and a position of a port in the sleeve44makes the amount of fuel injection adjusted. The amount of fuel injection is adjusted according to the position of revolution of the plunger42in the sleeve44. The electronic governor41controls the position of revolution of the plunger42.

The pinion43is attached and fixed to the plunger42, and is meshed with the rack45. The electronic governor41controls the rack45to be slid. The electronic governor41slides the rack45and changes the position of the rack45, and the pinion43is revolved. Thus, the position of the revolution of the plunger42in the sleeve44is controlled, and the amount of fuel injection is controlled. The electronic governor41is comprised with a linear solenoid or electronic cylinder and is controlled by the controller31. In this embodiment of the invention, an arm connected to the rack45is connected to the one-side of the solenoid, so that the arm operates the rack45. The electronic governor41operates the rack45according to the speed of the revolution of the engine by means of the controller31, and properly controls the amount of fuel injection.

A cold start device (hereinafter “CSD”)50is comprised at the side of the sleeve44. The CSD50changes the amount of fuel injection and the timing of fuel injection according to the combustion temperature.

The CSD attached to the fuel injection pump is described below.

FIG. 3illustrates partly sectional side view of the CSD.

The CSD50changes the amount of fuel injection and the timing of fuel injection according to the combustion temperature by means of opening or shutting an oil passage between a sub port44band a combustion gallery44c. The CSD50is comprised with a cylinder51, a combustion chamber52, a piston53, a spring54, and a piston chamber55. The volume of the wax in the cylinder51changes according to the combustion temperature, so that the piston53is slid, and the oil passage between the sub port44band the combustion gallery44cis opened or shut. The cylinder51is comprised in the combustion chamber52into which fuel flows.

The fuel is introduced into the sleeve44via the combustion chamber52. The cylinder51includes the wax that melts at a certain temperature. The piston53is attached to the tip of the rod of the cylinder51. The piston53is comprised in the piston chamber55. The piston53comprises a longitudinal hole, so that the upper space of the piston53can communicate with the lower space of the piston53. The piston53is slid according to the change of the volume of the wax and the oil passage between the sub port44band the combustion gallery44cis opened or shut. The lower portion of the piston53is contacted to the spring54, which biases the piston53upward.

In the CSD50, when the combustion temperature is low, the wax freezes and the piston53is slid upward, and the oil passage between the sub port44band the combustion chamber44cbecomes shut. This is an ON condition of the CSD50. As a result, the amount of fuel injection is increased and the timing of fuel injection is advanced. It is possible to change it for an electromagnetic valve to operate the CSD_50. In the controller31, the indication, whether the CSD50is “ON” or “OFF” is recognized as the condition of the CSD50.

The control system of the electronic governor41by means of the controller31is described below.

The controller31controls the position of the rack45in cranking the engine, so that smooth ignition of the engine is achieved and the black smoke is reduced in starting the engine. The start switch36is set in “OFF” position, and the rack45is operated toward the reduced fuel amount position until the zero fuel amount position after the conduction to the electronic governor41is released. The rack45is operated to the starting fuel amount position in starting the engine, so that the smooth start is achieved.

FIG. 4illustrates the operation of the rack.FIG. 4(a) illustrates the relation between the position of the rack and the speed of revolution of the engine.FIG. 4(b) illustrates the relation between the position of the rack and the elapsed time from starting.FIG. 5is a schematic illustration illustrating operation of the electronic governor and the starter motor in starting the engine.

In theFIG. 4(a), an axis of ordinate is the position of the rack; the upper side shows an increased fuel amount position. An axis of abscissa is the speed of revolution of the engine. A position R1of the rack is a starting fuel amount position of the rack45. The target value of the rack45is set in the position R1in starting the engine (when the start switch36is set in “START” position). In driving the engine1, R (the position of the rack45) is controlled according to V (the speed of revolution of the engine).

In theFIG. 4(b), an axis of ordinate is the ordered position of the rack, and an axis of abscissa is the elapsed time from starting. The two-dot chain line L0is the line showing the conventional operation of the rack. And the line L1is the line showing the operation of the rack in this embodiment. The hatched area is the area showing the tolerance of the time that the rack reaches the starting fuel amount position. The operating speed of the rack45as shown in L0or L1has no relation to the speed of revolution of the engine. The electronic governor41controls the position of the rack45to be the position ordered by the controller31. The actual position of the rack45at a certain time is different from the ordered position of the rack in terms of time and position.

The controller31orders the electronic governor41to control the rack45and operate the position of the rack45to the starting fuel amount position R1. The operating speed of the rack45is slower than the conventional and the arrival time is controlled as T1<T2. In theFIG. 4, the electronic governor41controls the rack45to be operated to the target position at a constant speed.

T1is simply the period that the rack45reaches the target position by the electronic governor41when the position R1is ordered as the target position, and T1depends on the performance of the electronic governor41. T1is usually about 0.1 seconds. As shown in the hatched area inFIG. 4, T2is as three times to eight times as T1. As a result, the amount of fuel injection is gradually increased, so that the excessive supply can be avoided and black smoke can be suppressed.

If it is desired to save fuel in starting the engine, the operating speed is constantly set and T2is set long. If it is desired to shorten the starting time, the operating speed is constantly set and T2is set short. If it is desired to save fuel in starting the engine and keep the conventional starting time, T2is set in 0.5-0.75 seconds. In this embodiment, we can achieve good engine start as T2is set at 0.7 seconds.

That is, the operating speed from the lowest position to the increased fuel amount position is set slower than the operating speed achieved by the highest operating speed of the actuator.

In this embodiment, as shown inFIG. 5, when the start switch36is set in “START” position, the rack45is operated from an initial situation (as shown inFIG. 5(a)) to the starting fuel amount position, and the starter motor32begins to crank. InFIG. 5, a graph in right side shows the relation between the position of the rack R and the elapsed time T. In this embodiment, the operating speed of the rack45is slower than the conventional one. Because of the cranking by the starter motor32, as shown inFIGS. 5(b) and (c), some fuel injections are done before the rack45reaches the starting increased fuel amount position, so that the amount of fuel injection can be gradually increased according to every timing by the cranking that injects fuel, thus there is a little error from the optimum amount of fuel injection for the ignition of the engine1.

As a result, saving fuel is achieved compared with the case that the rack45is operated to the position R0to supply enough for the engine start from the start.

A method to operate the rack45gradually to the starting increased fuel position is to change the target value of the rack according to time, or to control the inputs for the electronic governor41by means of a PI gain.

In the method to change the target value of the rack according to time, the integration of time is started when the start switch36is set in the “START” position. In the controller31, the target value of the rack45according to the integrated time is memorized, and the electronic governor41operates the rack45to the position of the target value. Thus, the rack45is gradually operated to the fuel increased side in starting the engine.

In the controller31, the target value of the rack45according to the integrated time is memorized in advance, so that the controller31can operate the rack45to the starting fuel position by means of the electronic governor41more slowly than the conventional.

FIG. 6illustrates an embodiment of the setting of the rack position according to the elapsed time.FIG. 6(a) illustrates an embodiment of the setting of the rack position according to the elapsed time.FIG. 6(b) illustrates an embodiment of the setting of the operating value of the rack according to the elapsed time.

In this embodiment as shown in theFIG. 6(a), the elapsed time, and the operated amount of the rack is divided into plural steps; each rack positions (R1a, R1b, R1c. . . R1) are set according to the elapsed times (t1, t2, t3. . . tn). And the controller31outputs the target value for the operation of the rack45according to this setting. As a result, the rack45is gradually operated to the starting fuel position R1. Thus, the target value of the rack45is set in plural steps according to the elapsed time from the engine start, and the target value is selected, so that easy setting of the operating speed of the rack, smooth engine start, saving a fuel and suppressing black smoke in starting the engine is achieved.

In this embodiment as shown inFIG. 6(b), the operating amount dR is set according to the elapsed times (t1, t2, t3. . . tn), and the rack45is operated in the amount dR after a certain period passes. The controller31outputs the rack position that is added to the former position in the amount dR when a certain period passes. As a result, the rack45is gradually operated to the starting fuel position R1.

The method to control the inputs for the electronic governor41by means of a PI gain is to adjust the operating speed of the rack45in a PI control used for the control of the electronic governor41.

FIG. 7illustrates a flow sheet illustrating the control of the electronic governor. In this embodiment as shown inFIG. 7, the position of an axle is detected in a processing61. In a processing62the target speed of revolution of the engine is computed by the detected position of the axle. In a processing63the target position of the rack is computed by comparing the computed target speed of revolution of the engine with the speed of revolution of the engine. The PI control is done in a processing64by comparing the computed target position of the rack with the position of the rack. The control signal from the processing64is converted into voltage in a processing65and is output to the electronic governor41comprised in the fuel injection pump in a processing66. In the processing66, the actual position of the rack is detected and used for the PI control in the processing64. The number of revolution of the engine1in a processing67is changed by adjustment of the electronic governor41in the processing66. The number of revolutions and the temperature of the cooling water of the engine1are detected in the processing67and are referred in the processing64,63and62. The condition of the engine1is affected by an outer load68. In the processing63, a starting signal for the starter motor32is detected, and the control of the rack is done according to the engine start.

A method of controlling the output for the electronic governor41by means of the PI gain is to slow the operating speed of the rack by the PI gain at the PI control for the electronic governor41. A feedback gain for the electronic governor41is weakened in starting the engine, so that a response to the target position is slowed and the operating speed of the rack45is slowed. As a result, it is easy and inexpensive to apply this to an existing composition.

It is possible to adjust the operating speed of the rack by the temperature.

FIG. 8illustrates a relation between the speed of the rack and a temperature. An axis of ordinate is the speed of the rack, and an axis of abscissa is the temperature.

A resistance of the lubricant at the lower temperature and an increase of fuel fluidity at the higher temperature increase the amount of fuel injection needed to start the engine1. For this purpose, an increase of the operating speed of the rack in a certain amount at low temperature or at high temperature, keeps the engine start smooth. It is also possible to adjust the operating speed of the rack by means of increasing or decreasing the time to reach the starting fuel amount position.

InFIG. 8, the area that is lower than a temperature A1is provided a lower temperature area and the area that is higher than a temperature A2is provided a higher temperature area, and the area between the A1and the A2is provided a normal temperature area. In the lower temperature area, the lower the temperature is, the more the operating speed of the rack is increased. In the higher temperature area, the higher the temperature is, the more the operating speed of the rack is increased. As a result, even if the temperature of the engine1is cold or hot, smooth starting of the engine can be achieved.

The relation between the operating speed of the rack and the temperature is memorized as a map in the controller31, and the operating speed of the rack according to the temperature is selected and the rack45is operated. The temperature that adjusts the operating speed of the rack is detected by a thermo sensor, as the temperature of the cooling water of the engine1, neighborhood of the engine, fuel, or lubricant.

A control flow of the amount of fuel injection in starting the engine is described below.

FIG. 9is a flow sheet illustrating the control of the engine.FIG. 10is a flow sheet illustrating the control of the amount of fuel injection in starting the engine.

The number of revolutions of the engine and predetermined number of revolutions to stop fuel injection are compared in a processing71. If the number of revolutions of the engine is smaller than a predetermined number of revolutions to stop fuel injection, then whether the start switch36is set in “START” position or not (whether the signal to start is turned on in the controller31or not) is detected in a processing72. If the start switch is not set in “START” position, then fuel injection stop control is done in a processing73, and it returns to the processing71. On the other hand, if the start switch is set in “START” position, then the starting amount control of fuel injection in the fuel injection pump34is done in a processing75.

If the number of revolutions of the engine is larger than a predetermined number of revolutions to stop fuel injection, then the number of revolutions of the engine and predetermined number of revolutions to finish starting the engine are compared in a processing74. If the number of revolutions of the engine is smaller than the predetermined number of revolutions to finish starting the engine, then the processing75is done. On the other hand, if the number of revolutions of the engine is larger than the predetermined number of revolutions to finish starting, then the fuel injection in the fuel injection pump34is normally controlled in a processing76.

In the control flow of the amount of fuel injection in starting the engine, as shown inFIG. 10, the control flow of fuel injection is selected according to the operating condition of the CSD50that controls the amount of fuel injection and the timing of fuel injection according to the combustion temperature. The control flow of fuel injection computes the target value of the rack position in starting the engine.

The operating condition of the CSD50is distinguished in a processing81. If the CSD50is operating, then the fuel injection is controlled according to the condition under which the CSD is operating, in a processing83. If the CSD50is not operating, then the fuel injection is controlled according to the condition under which the CSD is not operating, in a processing82. The control flow of the processing82and the processing83are the same. The parameters to compute the target value of the rack position in the processing82and in the processing83are different. So, the control of fuel injection according to the processing82is described below. In the processing82, the presence of the computation of the starting fuel amount position R0of the rack45and the time T2for the rack45to reach the R0is distinguished in a processing91. If they have not been computed, then the time T2is computed in a processing92, and if they have been computed, then the control flow is advanced to a processing93. In the processing93, whether a period of changing the position of the rack is passed is distinguished. If the period has not passed, then the processing82will end. If the period has passed, then the target value of the position of the rack45will be updated in a processing94. Thus, the electronic governor41operates and moves the rack45to the target position.

The amount of fuel injection is controlled according to the operating condition of the CSD50, thus by means of adjusting to the thermal-environmental change around the engine1, to smoothly start the engine and to suppress black smoke in starting the engine are achieved effectively.

Second Embodiment

A second embodiment of the invention about a control of the rack45in starting the engine is described below. In this embodiment, the operation of the rack is controlled in two steps; first, the rack45is operated to the position where the fuel can be compressed and supplied. Second, the rack45is gradually operated to the increased side. As a result, it is possible to shorten the time to operate the rack45in an area where the fuel cannot be compressed and supplied. And it is allowable to shorten the time for the engine1to be ignited.

FIG. 11illustrates an operation of the rack in this embodiment.FIG. 11(a) illustrates a relation between the rack position and the elapsed time.FIG. 11(b) illustrates a relation between the rack position at a point P2and the temperature. InFIG. 11(a), an axis of ordinate is an ordered position of the rack, and an axis of abscissa is the elapsed time from starting. A two-dot chain line L0is the line showing the conventional operation of the rack and a line L2is the line showing the operation of the rack according to the embodiment. The position R1is the starting fuel amount position, the position R2is the rack position where the fuel can be compressed and supplied in the fuel injection pump34.

The rack45is operated to the position R2, after the start operating of the engine1is begun. The rack45is gradually operated to the position R1from R2, that is, the operating speed before the point P2is same as the conventional one, and the operating speed after the point P2is slower than the conventional one.

In this embodiment, the time to operate the rack to the starting fuel amount position T2is the same as in first embodiment.

In the control of the rack after the point P2, the method like the above mentioned can be also taken. As a result, it is possible to shorten the time to operate to the point P2, so that when the control signal for still slower operation is output after the point P2, it is possible for an operator to smoothly start the engine1.

It is allowable to decrease the amount of increased fuel after the point P2where the fuel is actually compressed and supplied, so that it is possible to appropriately supply the fuel and prevent surplus supply of the fuel to the cylinder of the engine1. The above-mentioned method is also available for controlling the movement of the rack45after the point P2.

When the rack is operated from the lowest position to the starting fuel amount position, the operating speed is set in two steps. The later operating speed of the rack is reduced less than the operating speed of the rack up to the set intermediate rack target value R2. As a result, it is possible to shorten the time for the rack45to be operated to the minimum necessary fuel position for start the engine and it is possible to improve the response to the operation of the start switch.

The point P2is adjustable according to the temperature and is able to be controlled by means of the temperature detected by the controller31and the combustion temperature detected by the CSD50.

InFIG. 11(b), an axis of ordinate is the set rack position R2at the point P2, and an axis of abscissa is the temperature. A line L21is the line showing the change of the R2according to the temperature when the CSD50is turned off. A broken line L22is the line showing the change of the R2according to the temperature when the CSD50is turned on.

A resistance of the lubricant at the lower temperature and an increase of fuel fluidity at the higher temperature increase the amount of fuel injection needed to start the engine1. For this purpose, the lowest position to start the engine becomes higher fuel position than the normal condition, at the lower temperature or higher temperature. The controller31detects the temperature, and then it controls the first target position R2according to the temperature, so that it is possible to shorten the time it takes to ignite the engine and the time that the rack reaches the starting fuel amount position.

InFIG. 11(b), the area that is lower than a temperature A1is provided a lower temperature area and the area that is higher than a temperature A2is provided a higher temperature area, and the area between the A1and the A2is provided a normal temperature area. In the lower temperature area, the lower the temperature is, the more the operating speed of the rack is increased. In the higher temperature area, the higher the temperature is, the more the operating speed of the rack is increased. As a result, even if the temperature of the engine1is cold or hot, smooth starting of the engine can be achieved. The relation between the first target position of the rack45and the temperature is memorized as a map in the controller31, and the operating speed of the rack according to the detected temperature is selected and the rack45is operated. The temperature that adjusts the first target position of the rack is detected by a thermo sensor, as the temperature of the cooling water of the engine1, fuel, lubricant, or the engine neighborhood. When the CSD50is turned on, the position of the rack set by the R2is adjusted according to the situation. When the CSD50is off, the position R2is controlled as shown by the line L21. When the CSD50is turned on, as shown by the broken line L22, the position R2is reduced from the condition that the CSD50is off, and the amount of fuel supplied in starting the engine is adjusted. As a result, suppressing black smoke in starting the engine and saving fuel by means of suppressing the surplus supply to the engine is achieved.

Moreover, the operating speed of the rack45after the point P2can be adjusted according to the temperature or the condition of the CSD50. Thus, the engine start that is more adjusted to the condition of the engine is achieved.

For example, if the temperature of the cooling water of the engine1is lower than a certain temperature and the CSD50is turned on, the position of the rack corresponding to the point P2reduced to a point P20and the operating amount of the rack is increased after a point P22. The operating speed of the rack before the point P20is quick, and the rack position gradually becomes increased after the point P20. In this situation, the inclination of the line L20is larger than that of the line L2. Thus, if the temperature around the engine is low, the rack position corresponding to the point P2is reduced, and the operating speed of the rack for increased side is increased, so that saving a fuel and suppressing black smoke is achieved.

FIG. 12is a flow sheet illustrating the control of the amount of fuel injection in starting the engine.

The flow sheet as shown inFIG. 12corresponds to the processing75described in the first embodiment, and is fundamentally able to use the control flow as shown inFIG. 9.

The flow sheet as shown inFIG. 12is to select the control flow of the fuel injection according to the operating condition of the CSD50. The first target value of the rack position R2is computed by the control flow of the fuel injection.

The operating condition of the CSD50is distinguished in the processing81. The control flow of a processing182and a processing183are the same, so the processing182, for instance, is described below. In the processing182, the presence of the computation of the first target value R2of the position of the rack45is distinguished in a processing191. If the R2has not been computed, then the R2is computed in a processing192, and if the R2has been computed, then the control flow advances a processing193.

The processing193controls the operation of the rack after the point P2and controls the position of the rack45corresponding to the predetermined update period.

In the processing193, whether a period has passed or not is distinguished. If the period has not passed, then the processing182is finished, and if the period has passed, then the target value of the rack45is updated in a processing194. Thus, the electronic governor41operates and moves the rack45to the target position.

Third Embodiment

A third embodiment of the invention about a control of the rack45in starting the engine is described below.

In this embodiment, the operating speed of the rack is controlled in three steps; first, the rack45is operated to the position where the fuel can be compressed and supplied and, second, gradually operated to the increased side. Third, the operating speed of the rack is slowed after the ignition of the engine is recognized. The operating speed before the ignition of the engine is controlled more quick than the operating speed after the ignition of the engine.

As a result, it is possible to prevent the surplus supply of the fuel to the engine, and the lower fuel consumption and suppressing black smoke are achieved.

FIG. 13illustrates an operation of the rack in the third embodiment.FIG. 13(a) illustrates an operation of the rack.FIG. 13(b) illustrates a change of an operation of the rack according to the CSD. InFIG. 13, an axis of ordinate is an ordered position of the rack, and an axis of abscissa is the elapsed time from starting. In this embodiment, the operation of the rack45before a point P3is the same as in second embodiment. The point P3is the position of the rack where the ignition of the engine1is recognized and the time when the ignition of the engine1is recognized.

InFIG. 13(a), the rack45is operated to the position R2, after the starting operation of the engine1is begun. The electronic governor41sets the rack to the position R2as the first target value of the rack position. Thus, the operating speed before the point P2is same as the conventional one and the rack after the point P2the rack45is operated to the increased side at the set operating speed. In the control of the operation between the point P2and the point P3, the former control described in second embodiment is available.

After the controller detected the ignition of the engine1, the rack is operated by the operating speed that is set as the after ignition speed. The pick up sensor37detects the speed of revolution of the crankshaft of the engine1and is provided around the crankshaft of the engine1. The ignition of the engine is detected by the pick up sensor37.

After the ignition of the engine is detected, the operating speed of the rack is reduced less than the operating speed between the point P2and the point P3. As a result, the engine can start by a minimum amount of fuel injection by raising the amount of fuel injection from the situation of the engine ignition gradually. Saving a fuel in starting the engine and suppressing black smoke and reducing the exhaustion of carbon dioxide are achieved.

In this embodiment, the control according to the CSD is described below.

InFIG. 13(b), the point P20is the first target position of the rack45. A point P30is the position of the rack where the ignition of the engine1is recognized and the time when the ignition of the engine1is recognized.

If the CSD50is turned on, the operating speeds of the rack after the point P20and after the point P30are set according to the condition of the CSD50.

In the composition as shown inFIG. 13(b), the operating speed of the rack between the point P20and the point P30is increased compared to the condition that the CSD50is turned off. After the point P30, The operating speed of the rack is also increased compared to the operating speed after the point P3.

In the fuel injection pump providing the CSD, the operating speed of the rack after the ignition of the engine is controlled according to the operating condition of the CSD50, which makes it possible to control the amount of the fuel injection in starting the engine according to the characteristic of the fuel injection pump, to save a fuel, and to suppress black smoke.

A control system of the third embodiment is described below.FIG. 14is a flow sheet illustrating the control of the engine in the third embodiment. The flow sheet as shown inFIG. 14is almost the same as the flow sheet in the second embodiment, but there is a difference in the processing for distinguishing the ignition of the engine and changing the incremental amount of the rack position according to the presence of the ignition of the engine. The flow until the processing192is similar to the second embodiment. The ignition of the engine is distinguished in a processing201. If the engine1has not ignited, then the control is done according to the control flow for the situation that has not ignited in a processing195. The update period is distinguished in a processing193, and the target position of the rack is set in a processing194, according to the amount of the rack movement corresponding to the ignition at the update period. If the engine1has ignited, then the control is done according to the control flow for the situation that has ignited in the processing204. The update period is distinguished in a processing202, and the target position of the rack is set in a processing203, according to the amount of the rack movement corresponding to the ignition at the update period. In this embodiment, the amount of the rack movement at the update period is set as follows; the amount of the rack movement when the engine ignites is smaller than the amount of the rack movement when the engine doesn't ignite.

As a result, it is possible to control the amount of fuel injection according to the condition of the engine and to save fuel in starting the engine and to improve the durability of the filter and the catalyst in the exhaust passage.

Fourth Embodiment

A fourth embodiment of the invention is described below.

FIG. 15illustrates an operation of the rack.FIG. 15(a) is a schematic illustration illustrating a detection mechanism of a work machine.FIG. 15(b) illustrates a relation between the rack position and the elapsed time in being equipped with the work machine.

In this embodiment, the operating speed of the rack is controlled according a load given to the engine when the engine ignites. For example, when a work vehicle comprising the engine1is equipped with the work machine210, the work machine210gives load to the engine1when the engine ignites. It is necessary, in this case, to increase the fuel in order to keep the revolution of the engine1. In this embodiment, the connection of the work machine is detected by the controller31through a sensor211and others. If the engine1receives loads in starting the engine1, then the speed of the rack is increased. If the engine1receives few loads, then the speed of the rack is reduced.

As shown inFIG. 15(a), the sensor211is connected to the controller31, and the connection of the work machine is detected. The controller31controls the fuel injection pump34according to the connection of the work machine.

In starting the engine, the rack45is operated to the rack position R2. After the point P2, the rack45is operated to the increased side at the set speed. The controller31detects the ignition of the engine and the connection of the work machine. If the work machine is connected, then the rack45is operated to the increased side at the set speed in high load. If the work machine is not connected, then the rack45is operated to the increased side at the set speed in low load. In this embodiment, the speed at high load is larger than the speed before the engine ignites (between the point P2and P3). The amount of the fuel supply to the engine is controlled to increase so that the engine1is started enough. The speed at low load is smaller than the speed before the ignition of the engine, which saves a fuel for ignition.

In the control flow in this embodiment, a processing to distinguish the connection of the work machine is added to the above-mentioned flow204, and other control systems are the same as in third embodiment.

FIG. 16is a flow sheet illustrating the control of the ignition in the forth embodiment. The update period is distinguished in the processing202. If the update period has passed, then the connection of the work machine is distinguished in a processing212. If the work machine is connected, then the target value of the rack is updated with the increase in high load in a processing212. If the work machine is not connected, then the target value of the rack is updated with the increase in low load in a processing213. In this embodiment, the increase at high load is more than the increase without the ignition of the engine, and the increase at low load is less than the increase without the ignition of the engine.

As a result, it is possible to control the amount of fuel injection according to the loads that are given to the engine in starting the engine and it is possible to save fuel and to suppress black smoke, so that the operator can start the engine without considering the environment around the engine.

In this embodiment, like the above-mentioned, it is also possible to control the speed of the rack according to the condition of the CSD50. The control adjusting to the condition of the CSD50makes it possible to keep advantage of the CSD50, to save fuel and to suppress black smoke in starting the engine.

Fifth Embodiment

A fifth embodiment of the invention is as shown in the presentation below, making reference to the drawings.

The embodiment is about a fuel injection pump comprising a mechanical governor. The control of the rack45is the same as the above-mentioned control system.

Here, the fuel injection pump is described below.FIG. 17is a partly sectional side view of the governor.

The pinion43is attached and fixed to the plunger42, and is meshed with the rack45. The actuator162controls the rack45to be slid. The actuator162slides the rack45and changes the position of the rack45, and the pinion43is revolved. Thus, the position of the revolution of the plunger42in the sleeve44is controlled, and the amount of fuel injection is controlled. The cold start device (hereinafter “CSD”)50is comprised at the side of the sleeve44. The CSD50changes the amount of fuel injection and the timing of fuel injection according to the combustion temperature.

The composition of the governor41is described below. The amount of fuel injection by means of the fuel injection pump is mainly controlled by the amount of revolution of a spring lever shaft12. The governor41exists between the spring lever shaft12and the fuel injection pump, and controls the amount of fuel injection according to the number of revolution of the engine or others.

The governor41comprises, in a casing2, a governor weight8, a slide sleeve9, and governor lever assembles. The governor lever assembles are configured as a tension lever3, an adjust lever6, a governor lever7. The center of the tension lever3is pivoted to a revolution shaft4, which is provided in the transversal direction. The tension lever3is 3 direction extended shape and the edges are extended forward, downward and upward.

The front end of the tension lever3is connected to the spring lever11through a spring10. The upper end of the tension lever3is a contact portion14. The lower portion of the tension lever3is connected to the adjust lever6and to the governor lever7.

The upper end of the governor lever7is connected to the rear end of a control lever13operating the rack45and the amount of fuel injection is controlled. The adjust lever6and the governor lever7are connected to the tension lever3by means of an adjust shaft5, and are capable of inclining against the tension lever3. The adjust shaft5is an attachment pin for the governor lever7and the adjust lever6, and is provided in parallel to the revolution shaft4. The adjust lever6and the governor lever7are capable of inclining longitudinally.

Lower portion of the adjust lever6and the governor lever7are connected to a connection spring7b. The lower portions of the adjust lever6and the governor lever7are biased to be adjacent to each other.

When the spring lever shaft12is revolved clockwise to the drawing, the tension lever3is revolved counterclockwise through the spring10connected to the spring lever11and the control lever13is moved backward by the governor lever7. Thus, the amount of fuel supply to the engine is increased.

When the number of revolutions is increased, the governor weight8put out the slide sleeve9backward by the centrifugal force, and the adjust lever6is pushed in the direction of clockwise. Thus, the tension lever3is biased clockwise and inclined in the direction of clockwise without the position of the spring lever11is not changed. The control lever13is moved forward through the governor lever7, so that the amount of fuel supply to the engine.

In the rear face of the casing2, a stop solenoid161, an actuator162, and a limiter15are provided. The stop solenoid161revolves the governor lever7forward by means of contacting the governor lever7by a rod projected forward when the engine stops. Thus, the rack45is slid to the fuel decreased side, and the fuel supply by the fuel injection pump34is stopped. On the other hand, when the engine starts, the rod is returned backward and moved away from the governor lever7. The governor lever7is biased toward the casing2so that the upper portion of the governor lever7is revolved backward.

The tip of a rod comprised in the actuator162contacts the rear face of the governor lever7, so that the actuator162can adjust the position of the governor lever7.

The limiter15is provided at the upper portion of the casing2, and the amount of backward revolution is limited by the contact to a contact body14.

The control system of the governor41by the controller31is described below. The controller31controls the position of the rack45in cranking the engine, so that smooth ignition of the engine is achieved and the black smoke is reduced in starting the engine. When the start switch36is set in “OFF” position and the conduction to the stop solenoid161is stopped, then the rack45is operated to the fuel decreased side and stops at the position; there is no fuel supply. The controller31operates the rack45to the starting fuel amount position by conducting to the stop solenoid161and the actuator162, so that smooth starting of the engine is achieved.

In this embodiment, the operation of the rack45is the same as the operation as shown inFIG. 4.

In this embodiment, the governor lever7is controlled by the actuator162after the stop solenoid161is released.

A stop solenoid can be used as the actuator162. And it is advantageous as follows to use the stop solenoid whose returning speed (the sliding speed for the increased side) is slower than the stop solenoid161. By the situation that the actuator162contacts to the governor lever7, it is possible for the governor lever7to be held at the speed of revolution for the increased side, and the sudden fuel supply, in starting the engine, is avoided. While the start switch36is set in “START” position, the actuator162is released and the resistance to the revolution of the governor lever7is generated, so that the revolution of the governor lever7is controlled.

Thus, it is possible, in handily composing, to control the speed of revolution of the governor lever7for the increased side and to gradually increase the fuel supply in starting the engine and try to bring the fuel amount close to the best amount to ignite the engine.

In other composition of the actuator162, the actuator162is configured as a linear solenoid and the stroke of the linear solenoid is controlled sequentially by the controller31, and the revolution of the governor lever7is controlled.

That is, the position of the rack45is capable of being controlled by the controller31connected to the actuator162.

In this embodiment, as shown inFIG. 18, when the start switch36is set in “START” position, the rack45is operated from an initial situation as shown inFIG. 18(a) to the starting fuel amount position and the starter motor32begins cranking the engine1. InFIG. 18, a graph on the right side shows the relation between the position of the rack R and the elapsed time T. In this embodiment, the operating speed of the rack45is slower than the conventional, so that in the cranking of the starter motor32, the plural fuel injection is done, as shown inFIGS. 18(b) and (c), before the rack45arrival to the starting fuel amount position.

The amount of fuel injection can be gradually increased according to the each timing of the cranking that injects fuel, thus there is little error from the optimum amount of fuel injection for the ignition of the engine1.

As a result, saving fuel is achieved compared with the case that the rack45is operated to the position R0to supply enough for the engine start from the start.

A method to operate the rack45gradually to the starting fuel amount position is a method to change the target value of the rack according to the elapsed time, or a method to control the input to the actuator162by means of the PI gain.

In the method to change the target value of the rack according to time, the integration of time is started when the start switch36is set in the “START” position. In the controller31, the target value of the rack45according to the integrated time is memorized, and the actuator162operates the rack45to the position of the target value. Thus, the rack45is gradually operated to the fuel increased side in starting the engine.

In the controller31, the target value of the rack45according to the integrated time is memorized in advance, so that the controller31can operate the rack45to the starting fuel position by means of the actuator162more slowly than the conventional.

FIG. 19illustrates an operation of the governor lever and the actuator in a fifth embodiment. The governor lever7and the actuator162are operated in the order, (a), (b), and (c) inFIG. 19.

As shown inFIG. 19(a), if the engine stops, then the stop solenoid161and the actuator162are contacted to the governor lever7, and the stop solenoid161limits the backward revolution of the governor lever7.

When the start switch36is set in “START” position, the stop solenoid161is slid backward and the contact with governor lever7is released. Thus, the governor lever7is contacted to the actuator162and, the amount of projection of the actuator162determines the angle of the governor lever7. That is, the actuator162controls the position of the rack45through the governor lever7and the control lever13. The actuator162gradually revolves the governor lever7backward, and the governor lever7contacts the limiter15. Thus, the maximum amount of backward revolution of the governor lever7is determined.

From the stop solenoid161is released to the limiter15is contacted; the governor lever7is controlled by the actuator162, which can control the fuel supply in starting the engine.

The actuator162is connected to the controller31, which can variously operate.

It is possible to adjust the operating speed of the rack by the temperature, like the above mentioned.

Sixth Embodiment

In a sixth embodiment, a damper adjusts the speed of revolution of the governor lever and controls the speed of the rack45.

The governor lever is contacted to a resistance body, which reduces the operating speed of the governor lever to the starting fuel amount position.

FIG. 20illustrates an operation of the governor lever and the rack in a sixth embodiment.FIG. 20(a) illustrates a relation between the governor lever and the damper.FIG. 20(b) illustrates a relation between the rack position and the elapsed time.

In this embodiment, the damper165controls the operating speed of the rack45after the stop solenoid161is released. The damper165is the resistance body to the governor lever7.

The damper165is comprised at the rear portion of the casing of the fuel injection pump; a rod166is projected forward from the damper165. As shown inFIG. 20(a), until the stop solenoid161is released, there is a distance between the tip of the rod166and the governor lever7as a revolution angle of the governor lever7(D1). Thus, after the stop solenoid161is released, the governor lever7is revolved by the angle D1without contacting to the damper165.

The governor lever7is contacted to the tip of the rod166and after, the governor lever7is revolved receiving the resistance from the damper165, and the limiter15stops that revolution. The speed of revolution of the governor lever7is reduced by the resistance from the damper165while angles range D2.

InFIG. 20(b), the area until the point P2that has not received the resistance from the damper165corresponds to the angle range D1, and the area that has received the resistance from the damper165corresponds to the angle range D2. That is, a member operating the rack45is contacted to a resistance body that gives resistance according to the operation toward the fuel increased side, and the operating speed of the rack45is reduced. As a result, surplus fuel supply to the engine can be avoided, and saving a fuel and suppressing black smoke in starting the engine can be achieved. The characteristic of the damper165can be easily adjusted by means of the shape of orifice or others. A connecting member with a rod of the stop solenoid161is provided, so that the projection of the rod of the stop solenoid161can make the rod166of the damper165projected.

Seventh Embodiment

The composition that can change the contacting position between the damper and the governor lever7is described below, in a seventh embodiment.

FIG. 21illustrates a composition in a seventh embodiment.FIG. 21(a) illustrates a composition of the connection between the damper and the actuator.FIG. 21(b) illustrates a relation between the rack position and the elapsed time in this embodiment.

A casing of the damper165is connected to a rod of an actuator167, and the actuator167can adjust the position of the damper165. Thus, the timing that the damper165contacts to the governor lever7can be changed. As shown inFIG. 21(b), the position of the damper165is adjusted in a range D3inFIG. 21(a), and then the timing that the operating speed of the rack45becomes gradual can be adjusted. The position of the damper165operated by the actuator167is capable of adjusting according to the above-mentioned CSD50, the temperature of the cooling water, the temperature of lubricant, or the temperature of fuel. The method as shown inFIG. 11(a) is available as the method to adjust the position.

As a result, it is possible to control the fuel smoothly and quickly by means of controlling the amount of fuel supply in starting the engine according to the environment around the engine, and saving a fuel and suppressing black smoke is achieved.

Eighth Embodiment

An eighth embodiment of the invention is as shown in the presentation below.

In this embodiment, the resistance force of the damper is controllable, that is, the operating speed of the rack45is controlled by controlling the speed of revolution of the governor lever7according to the load condition or the temperature of the engine.FIG. 22illustrates a composition in eighth embodiment.FIG. 22(a) illustrates a composition of the resistance force of the damper is controllable.FIG. 22(b) illustrates a relation between the rack position and the elapsed time.

A damper170comprises a piston in the closed cylinder, and a rod that contacts to the governor lever7is connected to the piston. The cylinder is filled with hydraulic fluid, and the front portion of the cylinder is connected with the rear portion of the cylinder through a variable valve171. By adjusting the variable valve171, it is possible to control the resistance that is from outflow and inflow of hydraulic fluid by the movement of the piston.

That is, as shown inFIG. 22(b), the governor lever7is contacted to the damper170, and the variable valve is operated, so that the resistance of hydraulic fluid in the cylinder is controlled and the operating speed of the rack45can be controlled. The variable valve171is connected to the controller31, and it is possible to supply fuel according to the environment around the engine by means of adjusting the variable valve171according to the ignition of the engine or the connection of the work machine.

Ninth Embodiment

The composition that can change the contacting position between the damper and the governor lever7, using a temperature-sensitive element, is described below, in a ninth embodiment.

FIG. 23illustrates a composition in ninth embodiment.FIG. 23(a) illustrates a composition of the connection among the temperature-sensitive element, the damper, and the actuator.FIG. 23(b) illustrates a relation between the rack position and the elapsed time in this embodiment.

The casing of the damper165is connected to a tip of the temperature-sensitive element180. The temperature-sensitive element180is equipped with the casing2, and when the temperature-sensitive element is warmed, the tip is projected toward the governor lever7. When the temperature-sensitive element is cooled, the tip is returned away from the governor lever7.

The temperature-sensitive element180is provided in a fuel chamber181comprised in a fuel passage, so that the temperature of fuel is transferred. Thus, the position of the damper165is controlled according to the temperature of fuel. If the temperature of fuel is low, the timing of contacting to the governor lever7is delayed, and the initial fuel supply is increased. That is, a point P4is changed to the point P2inFIG. 22(b). As a result, it is available to smoothly start the engine by increasing the fuel under the low temperature condition. It is possible to control the fuel smoothly and quickly by means of controlling the amount of fuel supply in starting the engine according to the environment around the engine, and saving a fuel and suppressing black smoke is achieved. The wax used in the CSD50is applicable as the temperature-sensitive element.

INDUSTRIAL APPLICABILITY

According to the invention of the present application, the fuel injection device can be suitably applicable to a control mechanism of an amount of fuel.