JP2007092626A - Engine for work equipment - Google Patents

Abstract

An automatic control of an output according to a change in engine load reduces a handling burden on a work driver, and a fuel injection control from a pressure accumulating chamber simplifies a control mechanism to improve control responsiveness and fuel consumption. Improvement and noise reduction.
An isochronous control drive map (A) for maintaining a constant engine speed even when a load on the engine fluctuates, and a droop control drive map (B) for varying the engine speed in accordance with the load. Set and keep the engine speed constant even when the load fluctuates using the isochronous control drive map (A) during normal load work, and increase the load using the droop control drive map (B) when not working Accordingly, the engine is provided with a control device that automatically adjusts the fuel injection amount from the pressure accumulation chamber to each cylinder so as to allow a decrease in the engine speed.
[Selection] Figure 21

Description

  The present invention relates to an engine mounted on a working machine such as a combine, a tractor, or a rice transplanter.

2. Description of the Related Art Agricultural machines such as tractors and combines control engine output in response to various load conditions such as traveling for simple movement and traveling while driving the working machine.
For example, an actuator for control adjustment is connected to a governor, an actuator is operated in accordance with a work mode of a work machine, a fuel injection amount is changed by the governor, and an engine output is controlled.
JP 2000-220486 A

  Agricultural working machines are greatly different in load fluctuations applied to the engine during traveling such as cutting and plowing. Furthermore, during the work, the engine load greatly fluctuates due to the amount of crops and the cultivated land, and the engine speed is likely to change, making it difficult for the operator to operate.

  Therefore, the present invention aims to reduce the handling burden on the work driver by automatically controlling the output according to engine load fluctuations. Conventionally, as described above, the governor is set according to the work mode. Adjustment and engine rotation control are performed, but this method of automatically adjusting the governor has a problem that the control mechanism becomes complicated and the control responsiveness is poor.

  Therefore, in the present invention, by using a common rail system that performs fuel injection control from the pressure accumulating chamber to each cylinder of the engine, the control mechanism is simplified, control responsiveness is improved, fuel efficiency is improved, and noise is reduced. Let it be an issue.

The above object of the present invention is achieved by the following configuration.
That is, the invention of claim 1 includes an isochronous control drive map A that maintains a constant engine speed even when the load on the engine fluctuates, and a droop control drive map B that varies the engine speed according to the load. The engine speed is kept constant even when the load fluctuates using the isochronous control drive map A during normal load work, and the droop control drive map B is used during non-work as the load increases. The working machine engine is provided with a control device that automatically adjusts the fuel injection amount from the pressure accumulating chamber to each cylinder so as to allow the engine speed to decrease.

According to the first aspect of the present invention, the engine control mode is changed by switching the work implement between normal work and non-work.
According to a second aspect of the present invention, a heavy load control drive map C for increasing the engine speed as the load increases is set, and pressure accumulation is performed based on the heavy load control drive map C during heavy load work. By configuring the engine so as to control the fuel injection amount from the chamber to each cylinder, it can cope with particularly heavy work.

  According to the first aspect of the invention, during normal load work, a constant engine speed is always maintained even when the load fluctuates, and the work can be stably performed at a constant work speed. Can be operated safely and easily. In addition, when traveling when not working, for example, if the brake is applied to reduce or stop the traveling speed, the engine speed decreases as the traveling load increases. In addition, the stop can be performed safely, and for example, the operator can detect the load state of the engine when climbing.

  Further, in the invention according to claim 2, when the work load is larger than the normal work load, the engine speed is increased to increase the output, so that the work limit can be widened, and a wide range of situations can be handled. Work efficiency.

  First, the outline | summary is demonstrated about a pressure accumulation type fuel-injection diesel engine. The accumulator fuel-injected diesel engine is a system in which a fuel supply to an injector that injects fuel into each cylinder in a diesel engine is performed through a common rail (pressure accumulator chamber) at a required pressure. The fuel injection control state will be described.

  The fuel in the fuel tank 10 is sucked into the high pressure pump 13 driven by the engine through the fuel filter 12 through the suction passage 11, and the high pressure fuel pressurized by the high pressure pump 13 is guided to the common rail 15 through the discharge passage 14. Stored.

  The high-pressure fuel in the common rail 15 is supplied to injectors (fuel injection valves) 17 corresponding to the number of cylinders through the high-pressure fuel supply passages 16, and for each cylinder based on a command from an engine control unit (hereinafter referred to as “ECU”) 18. The injector 17 is opened to supply high pressure fuel into each combustion chamber of the engine.

Excess fuel (return fuel) in each injector 17 is led to a common return passage 20 by each return passage 19 and returned to the fuel tank 10 by this return passage 20.
In addition, a pressure control valve 21 is provided in the high-pressure pump 13 in order to control the fuel pressure in the common rail 15 (common rail pressure). This pressure control valve 21 adjusts the flow area of the return path 20 of the surplus fuel from the high-pressure pump 13 to the fuel tank 10 by a duty signal from the ECU 18, thereby adjusting the fuel discharge amount to the common rail 15 side. Thus, the common rail pressure can be controlled. Specifically, the target common rail pressure is set according to the engine operating conditions, and the common rail pressure is fed back via the pressure control valve 21 so that the common rail pressure detected by the common rail pressure sensor 22 matches the target common rail pressure. Control.

FIG. 2 is a signal input control block diagram of the ECU 18.
Engine speed sensor 30, cylinder discrimination sensor 31, accelerator pedal or accelerator lever opening sensor 25, intake air turbo pressure sensor 33, intake temperature sensor 34, radiator water temperature sensor 35, intake air temperature sensor 36, position of work lever Information on the sensor 37, common rail pressure sensor 22, and timer 42 is input to the ECU 18, and a glow plug control signal 38, an injector control signal 39, and a common rail pressure control signal 40 are output from the ECU.

Next, the control state of the diesel engine will be described with reference to a data map and a flowchart.
In a diesel engine, it is known to perform a pilot injection that injects a small amount of fuel in a pulse manner prior to a main injection, thereby shortening an ignition delay and reducing a so-called knocking noise peculiar to a diesel engine.

  Conventionally, the pilot injection is fixed to be performed once or twice before the main injection, but in the embodiment of the present invention, this is changed according to the state of the engine, thereby reducing noise and incomplete combustion. The generation of white smoke and black smoke is suppressed.

The engine warm-up state is detected by the radiator water temperature sensor 35, and pilot injection is controlled as follows.
As shown in FIG. 3, the ECU stores a pilot injection control map including the relationship between the water temperature, the injection timing, the common rail rail pressure 52, and the number of pilot injections. The pilot injection timing, the number of times and the common rail pressure are determined according to the detected temperature of the water temperature sensor 35. Change control is performed as follows.

  When the engine is cold, the injection timing is advanced, the number of injections is increased, the common rail pressure is increased, the fuel is atomized, the ignitability is improved, the noise is reduced, and the generation of white smoke is suppressed. Yes.

  This pilot injection control map (FIG. 3) has start-up injection timing data 50 used when starting the engine. The starting injection timing data 50 is data used until the water temperature is low and reaches a predetermined rotation speed, and is delayed from the normal data 51. By using this data, the generation of black smoke at start-up can be suppressed.

  At the time of start-up, since the common rail pressure is low, fuel injection is not immediately performed even if the ignition key is turned. The combustion chamber is warmed by the glow and waits until the common rail pressure reaches a predetermined pressure.

  Further, the relationship between the water temperature, the injection timing, the common rail rail pressure, and the number of pilot injections can be stored as a calculation formula instead of a map. In this case, the capacity of the storage unit can be reduced.

Furthermore, the injection timing to be changed depending on the water temperature may be changed not only for the pilot injection but also for the main injection.
After the engine is started, pilot injection is controlled by a pilot injection control map showing the relationship between the engine speed and the fuel injection amount in FIG. The pilot injection is performed once to twice, but a transition region for changing the number of pilots by shifting the time for each cylinder is provided between the pilot number regions.

  In the transition region, for example, in the case of a four-cylinder engine, when switching from no pilot to one pilot as shown in FIG. By increasing the number of cylinders that perform pilot injection at regular intervals, a rapid increase in noise can be suppressed.

The start of pilot injection in this transition region may be started at equal intervals by two cylinders with the firing order set as the cylinder order or by skipping one cylinder as shown in FIG.
Diesel engines generate black smoke and increase noise during sudden acceleration, etc. To prevent this, the opening speed of the accelerator pedal is detected and the interval between the number of pilot injections and the main injection is changed. I am doing so.

  In the acceleration state as shown in FIG. 7, pilot injection control as shown in FIG. 8 is performed. In other words, the pilot injection is decreased and the pilot injection timing is shortened as the acceleration is accelerated from the rapid acceleration, and the pilot injection amount is increased.

  Pilot injection is also performed when misfire is detected by the engine speed sensor 30 in steady rotation. FIG. 9 shows pilot injection at the time of misfire detection. In the first misfire detection, the amount of pilot injection is small and the interval from the main injection is short, but if this still fails, the amount of pilot injection is increased. And widen the interval with the main injection. This suppresses an increase in combustion noise and suppresses the generation of white smoke. TDC in the figure indicates the top dead center of the crank.

  FIG. 10 is a map for correcting the common rail pressure from the outside air temperature, that is, the temperature measured by the intake temperature sensor 34 and the radiator water temperature sensor 35. When starting the engine in a cold region, the common rail pressure is increased to reduce the fuel particles. I am trying. Thereby, generation | occurrence | production of the white smoke at the time of starting can be suppressed. Further, by not performing fuel injection until the above-mentioned common rail pressure is reached, it is possible to prevent the combustion chamber from staying in useless fuel, improve the ignitability, and suppress the generation of black smoke.

  In a diesel engine that controls the common rail pressure, the fuel injection amount can be changed without changing the injection time by changing the common rail pressure. Therefore, when the engine overheat is detected by the radiator temperature sensor 35 or the like, the common rail pressure is changed. If the pressure is lowered, the amount of fuel injection is reduced and the rotation can be lowered. At this time, instead of directly reducing the common rail pressure, a pseudo abnormal high pressure signal may be sent to the common rail pressure detection signal to reduce the rail pressure using an automatic lowering function at the time of abnormal high pressure.

  If the engine is stopped for a long period of time, oil will be removed from the sliding parts in the engine, and a sudden increase in rotation at the start may cause engine seizure. This time is measured by the timer 42, and when a predetermined time elapses, the engine is prevented from being damaged by moderately increasing the rotation regardless of the rapid opening operation of the accelerator.

  FIG. 11 is a fuel injection control map at the time of starting rotation. The normal accelerator control F that enables a rapid increase in rotation at the normal starting time is used, and the starting after a long stop is performed by using a gentle rotation increasing control G. Control the injection amount.

  FIG. 12 shows an example in which the non-injection cranking control H that does not increase the rotation of the engine for several seconds even when the accelerator is opened and has the time for feeding the lubricating oil is used for starting after a long stop. It is. In this case, it is also possible to increase the rotation by detecting that the oil pressure of the lubricating oil has risen instead of elapse of a predetermined time.

FIG. 13 is a control flowchart using the above accelerator maps, and selects the controls F, G, and H to be used at the set elapsed time after the engine is stopped.
This start control is also effective in a case where a starter with the manual accelerator being opened may be used in an agricultural machine in which the accelerator is manually operated.

  Agricultural machines sometimes run and stop repeatedly while the work machine is fully rotated. In this case, the engine is driven from the stop while the engine is fully rotated by the manual accelerator. In this case, the traveling speed is adjusted by the clutch operation so as not to start suddenly, but it is dangerous if not used. Therefore, as shown in FIG. 14, a normal drive L and a start drive M are provided in the fuel injection control map, and when starting with the manual accelerator full as shown in the flowchart of FIG. 15, the start drive M is used for driving. The torque is lowered than usual to reduce the starting shock.

  In the above case, as another means, as shown in FIG. 16, the fuel injection control map is provided with a start drive S having a reduced rotational speed, and the engine rotation at the start is reduced as shown in FIG. You may do it.

  Agricultural machines such as combine and tractor perform spot turn or sudden turn in order to reduce the turning radius, but at this time the engine is loaded and noise increases. Pilot injection is used to prevent this. The pilot injection is started by a signal that the turn or the sudden turn is started as turning information of the steering wheel or the like, and the pilot injection is ended at the end of the turn and only the main injection is made. The number of pilot injections increases from 1 to 2 and decreases.

  In a diesel engine, if the fuel injection amount is increased by a rapid accelerator opening operation, the rotation cannot catch up and black smoke is generated. However, by performing the control of FIG. I try to suppress it. That is, when the accelerator opening speed is larger than the set value, the fuel injection is performed in accordance with the rotational speed obtained by reducing the fuel injection amount by 50 rpm.

  Further, in order to prevent black smoke from being generated due to the turbocharger's supercharging pressure being low in a diesel engine with a turbocharger that compresses intake air, when the supercharging pressure is lower than a set value as shown in the flowchart of FIG. The fuel injection is controlled with an injection amount map lower than the normal fuel injection amount map. In this case, as shown in the flowchart of FIG. 20, if the supercharging pressure is low, the common rail pressure can be increased to atomize the fuel and suppress the generation of black smoke.

  Agricultural implements equipped with a diesel engine will stop the engine because the load is abnormally high if the work is started with the hydraulic equipment of the main unit such as a combine or tractor not warmed up even if the engine is warmed up. Sometimes. Therefore, the hydraulic pressure of the main body is detected and sent to the ECU, and the injection timing is adjusted so that the torque is increased when the hydraulic pressure is low.

  As shown in FIG. 21, the ECU of the accumulator fuel-injected diesel engine of the farm work machine is provided with three types of control modes, that is, a travel mode M1, a normal work mode M2, and a heavy work mode M3 in relation to the rotational speed and the output torque.

  The traveling mode M1 is a droop control B in which the output fluctuates due to fluctuations in the number of rotations, and is used when traveling without farming. When traveling for mere movement, for example, if braking is applied to reduce or stop the traveling speed, the engine speed decreases as the traveling load increases. In addition, the stop can be performed safely, and for example, the operator can detect the load state of the engine when climbing.

  The normal work mode M2 is an isochronous control A in which the rotation speed is constant and the output is changed according to the load even when the load fluctuates, and is used when normal farm work is performed. For example, if it is a combine, it is a harvesting work, and if it is a tractor, it is a cultivating work, and even if there is a lot of harvest and the load increases, the output will fluctuate even if the cultivated land is hard and the cultivating blade is resisted. The rotation speed is maintained, so that the driving operator can easily operate.

  In the heavy work mode M3, as in the normal work mode M2, even when the load fluctuates, the isochronous control A that changes the output according to the load at a constant rotational speed is increased near the load limit to increase the output by increasing the rotational speed. This is a control with heavy load control C added, especially when farming is performed near the load limit. For example, when working on a tractor with a tractor, even if it encounters a particularly hard cultivated land, the engine output increases beyond the normal limit, so the work is not interrupted.

  The engine speed increases at the time of work near the engine output limit, so that the traveling speed increases. To prevent this, a transmission may be provided in the traveling transmission path to control the traveling speed to be constant.

  These work modes M1, M2, and M3 are configured to be switched by an operation of a work mode changeover switch, a shift operation of a travel shift lever, an operation of turning on and off a work clutch, or the like.

That is, the operation mode changeover switch may be configured to arbitrarily switch between the traveling mode M1, the normal operation mode M2, and the heavy operation mode M3.
Further, when the sub shift lever is shifted to the “high speed” position, the shift operation may be detected by a limit switch or a potentiometer and automatically switched to the travel mode M1.

Further, a vehicle speed sensor may be provided so that when the actual vehicle speed exceeds the set speed, the mode is automatically switched to the travel mode M1.
Further, for example, in a combine, when the harvesting clutch and the threshing clutch are operated together, this state may be detected by a limit switch or a potentiometer and automatically switched to the normal work mode M2. . As a result, in normal mowing and threshing work, the engine speed is maintained constant even when the load increases, and the rotation speed of the barrel of the threshing section, the swing speed of the swing shelf, the air volume of the red pepper, etc. are kept constant. It is possible to work with high efficiency while maintaining.

  Further, for example, in a tractor, when the shift lever enters the high speed range, this may be detected by a limit switch or a potentiometer and automatically switched to the heavy work mode M3. That is, in a tractor, on the road or in a field, there are cases where it is going to start with the speed change lever in the high speed range. In such a heavy load state, the engine rotation is increased against the load. , Smooth start and occurrence of engine stall can be prevented.

  Further, for example, when a tilling clutch is engaged and operated in a tractor, this state may be detected by a limit switch or a potentiometer and automatically switched to the heavy work mode M3. In other words, in a state where the tillage work is performed while rotating the tillage rotary at a low speed while suppressing noise, when the hard board is reached, the engine rotation speed is increased to overcome this heavy load and perform the tillage work. Work efficiency can be improved.

  The heavy load near the overload in the heavy work mode M3 increases the rotation to the engine torque limit value as shown in FIG.

Schematic configuration diagram of an accumulator fuel injection diesel engine according to the present invention Control block diagram of an embodiment of the present invention The optimal rail pressure by the water temperature of this invention Example, and an injection timing map. Control map of engine speed and pilot injection number of embodiment of the present invention Cylinder control map for pilot injection at start-up Cylinder control map for pilot injection at start-up in another embodiment Rotation rising pattern diagram of the embodiment Pilot injection pattern diagram at the time of rotation rise of the embodiment of the present invention Injection timing chart at the time of misfire of the embodiment of the present invention Common rail pressure correction diagram of the embodiment of the present invention Start control map of the embodiment of the present invention Start control map according to another embodiment of the present invention FIG. 3 is a control flowchart for starting the engine according to the embodiment of the present invention. Drive map of the embodiment of the present invention Start control flowchart of the embodiment of the present invention Drive map of another embodiment of the present invention Start control flow chart of another embodiment of the present invention Sudden accelerator start control flowchart of the embodiment of the present invention Booster pressure control flowchart of the embodiment of the present invention Booster pressure control flowchart of another embodiment of the present invention Rotation speed and output control mode diagram of the embodiment of the present invention Rotational speed and output control map according to another embodiment of the present invention

Explanation of symbols

A Drive map for isochronous control B Drive map for droop control C Drive map for heavy load control 10 Fuel tank 11 Suction passage 12 Fuel filter 13 Supply pump 14 Discharge passage 15 Common rail (accumulation chamber)
16 High pressure fuel supply passage 17 Injector (fuel injection valve)
18 Engine control unit (ECU)
DESCRIPTION OF SYMBOLS 19 Return path 20 Return path 21 Pressure control valve 22 Common rail pressure sensor 25 Opening sensor 30 Engine speed sensor 31 Cylinder discrimination sensor 33 Turbo pressure sensor 34 Suction temperature sensor 35 Radiator water temperature sensor 36 Suction air temperature sensor 37 Work lever position sensor 38 Glow plug control signal 39 Injector control signal 40 Common rail pressure control signal 42 Timer

Claims (2)

  An isochronous control drive map (A) that maintains a constant engine speed even when the load on the engine fluctuates and a droop control drive map (B) that changes the engine speed according to the load are set. The engine speed is kept constant even when the load fluctuates using the isochronous control drive map (A) during load work, and the engine is increased as the load increases using the droop control drive map (B) during non-work. A working machine engine comprising a control device that automatically adjusts a fuel injection amount from a pressure accumulating chamber to each cylinder so as to allow a decrease in rotational speed.   A heavy load control drive map (C) for increasing the engine speed as the load increases is set. Based on this heavy load control drive map (C) during heavy load work, the pressure accumulator chamber is connected to each cylinder. The working machine engine according to claim 1, wherein the fuel injection amount is controlled.

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