JP2008008208A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent excessive fuel injection caused by the accelerator operation of an engine. <P>SOLUTION: An engine mounted to a working vehicle is constituted as an engine provided with an injection mode change-over device characterized by enabling the change-over of a fuel injection control mode between an on-road mode in road traveling during which a time response of an accelerator opening responds quickly to actual operation and a work mode in work during which an actual operation quantity is corrected and a response is lowered in speed. When it is determined that engine operation is racing operation from a rising state of engine speed to accelerator operation, the engine responds to keep a fuel injection quantity low with respect to excessive accelerator operation. When an intake air temperature and a cooling water temperature are set values or smaller and accelerator operation speed is a set value or higher at no-loading, it is determined that engine operation is racing operation under a cold engine condition, and fuel injection timing is advanced and the number of times of pilot injection is increased. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine mounted on a work vehicle or a general vehicle.

Conventionally, the engine idling control device while the vehicle is stopped includes a vehicle stop state detection means, an accelerator opening state detection means (or an exhaust temperature state detection means), an accelerator opening time measurement means, and the like. When the vehicle is stopped and the accelerator opening is large and the engine is open (or the exhaust gas temperature is equal to or higher than a predetermined value) and the predetermined time has elapsed, it is determined that the engine is idling and the accelerator opening is By operating to the closed side, the intake air amount is suppressed and the fuel injection amount is also reduced, so that the engine speed can be lowered and the engine can be brought into an idle state, so that the amount of heat sent from the engine is reduced and the exhaust system is overheated. Is disclosed to prevent deterioration and damage of the exhaust system due to abnormal overheating. (For example, see Patent Document 1)
Japanese Patent Laid-Open No. 10-184396

  However, as described above, when it is determined that the engine is in the idling state as the engine idling control device while the vehicle is stopped, the engine speed is decreased by operating the accelerator opening degree to the closed side. Although the engine can be set to the idle state, when the work is performed on the work vehicle, the accelerator opening is normally set to the fully opened state and the work is started without decreasing the engine speed. In this case, there is an operational difficulty that it becomes easy to discharge white smoke due to excessive fuel injection due to idling and deteriorates fuel consumption, and requires a delicate accelerator operation. In particular, the emission of white smoke becomes noticeable when the friction of the engine drive unit is large or when the inertia mass of the vehicle is large immediately after starting.

  In view of the above, the present invention intends to eliminate operational difficulties that require a delicate accelerator operation during work.

  According to the first aspect of the present invention, in the engine mounted on the work vehicle, the injection control mode (1) at the time of fuel injection is changed to a road mode in road running or the like in which the time response of the accelerator opening quickly responds to the actual operation value. The engine is provided with an injection mode switching device characterized in that it can be switched between (1a) and a work mode (1b) in a work in which the actual operation value is corrected and responded gently.

  With such a configuration, when traveling on the road with a work vehicle, the accelerator opening of the engine can be made to be a driving maneuver for the operation of the operator by switching the injection control mode (1) to the road mode (1a). In addition to being able to respond quickly so as not to cause a problem, when performing work (for example, a farm field or the like), by switching the injection control mode (1) to the work mode (1b), the accelerator opening of the engine can be set to the operator. It can be made to respond slowly by correction so as to suppress idling even for a sudden operation.

  The invention according to claim 2 is characterized in that when it is determined that the idling operation is performed from the state in which the engine speed is increased with respect to the accelerator operation, a response for suppressing the fuel injection amount with respect to the excessive accelerator operation is performed. The configuration of the engine.

  With such a configuration, when the engine speed rapidly increases with respect to the accelerator operation, it is determined that the engine is idling, and the response of the accelerator opening is changed from an abrupt characteristic to a gradual characteristic, thereby unnecessary fuel injection. Can be prevented.

  In the third aspect of the invention, when no load is applied, when the intake air temperature and the cooling water temperature are lower than the set values and the accelerator operation speed is higher than the set value, it is determined that the air-blow operation is performed at the time of low temperature cooling, and the fuel injection timing is advanced. The engine configuration according to claim 2, wherein the angle is increased and the number of pilot injections is increased.

  With such a configuration, when the temperature of the intake air and cooling water is low below the set value and the accelerator operation is suddenly accelerated above the set value, it is determined that the engine is idling without load when the engine is cold. The idling operation can be suppressed by increasing the number of pilot injections together with the advance of the fuel injection timing.

  In the first aspect of the present invention, as described above, in the work vehicle, when traveling on the road, the road is switched to the road mode (1a), and the accelerator opening of the engine is quickly responded to the operation of the operator so as not to hinder the driving operation. Thus, on-road driving can be performed accurately, and at the time of work (for example, a field), the operation mode (1b) is switched, and the accelerator opening of the engine is suppressed by correcting the sudden operation of the operator. Since it can be made to respond slowly, excessive fuel injection can be suppressed and white smoke emission and fuel consumption deterioration can be reduced without requiring a delicate accelerator operation as in the prior art.

  In the second aspect of the invention, as described above, when the engine speed rapidly increases with respect to the accelerator operation, it is determined that the engine is idling, and the response of the accelerator opening is changed from a rapid characteristic to a gentle characteristic. In addition, unnecessary fuel injection can be prevented and black smoke emission can be suppressed even when the accelerator is operated suddenly.

  In the third aspect of the invention, as described above, when the temperature of the intake air and the cooling water is a low temperature that is lower than the set value and the accelerator operation is a sudden acceleration that is higher than the set value, It is possible to suppress misfire and white smoke due to the idling operation by determining the idling operation and advance the fuel injection timing, and it is possible to prevent an increase in combustion noise due to the advance angle by increasing the number of pilot injections. .

  In the engine mounted on the work vehicle, the injection control mode 1 at the time of fuel injection is corrected with respect to the actual operation value and the road mode 1a in the road traveling in which the time response of the accelerator opening responds quickly to the actual operation value. It is possible to switch to the work mode 1b at the time of the work that makes a response slowly. Further, when it is determined that the idling operation is performed from the state in which the engine speed is increased with respect to the accelerator operation, a response for suppressing the fuel injection amount is performed with respect to the excessive accelerator operation. In addition, when there is no load and the intake air temperature and the coolant temperature are lower than the set values and the accelerator operation speed is higher than the set values, it is determined that the engine is idling when the engine is cold and the fuel injection timing is advanced. Increase the number of pilot injections.

Embodiments of the present invention will be described below with reference to the drawings.
An outline of the pressure accumulation type fuel injection diesel engine will be described with reference to a system diagram as shown in FIG. The accumulator fuel injection is performed through a common rail 10 (accumulation chamber) having a required pressure for fuel supply to a fuel injection device that injects fuel into each cylinder.

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

  The high-pressure fuel in the common rail 10 is supplied to the fuel injection valves 17 corresponding to the number of cylinders through the high-pressure fuel supply passages 16, and the fuel injection valves 17 for each cylinder based on commands from the engine control unit 18 (hereinafter referred to as ECU). Is opened, and high-pressure fuel is injected into each combustion chamber of the engine.

Excess fuel (return fuel) in each fuel injection valve 17 is guided to a common return passage 20 by each return passage 19 and returned to the fuel tank 11 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 10 (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 11 according to the duty signal from the ECU 18, thereby reducing the fuel discharge amount to the common rail 10 side. It can be adjusted to control the common rail pressure.

  Specifically, the target common rail pressure is set according to the engine operating conditions, and the common rail pressure is feedback-controlled through 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. .

  As shown in FIG. 5, the ECU 18 of the pressure accumulation type fuel injection diesel engine in the work vehicle (agricultural work machine) has 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. Is provided.

  The traveling mode M1 is used when traveling without farming as droop control in which the output fluctuates due to fluctuations in the rotational speed. For example, when the traveling speed is reduced or stopped by applying a brake, As the traveling load increases, the engine speed decreases, so the traveling speed can be reduced or stopped safely.

  The normal work mode M2 is used when performing normal farm work as isochronous control in which the rotation speed is constant even when the load fluctuates and the output is changed according to the load. Sometimes, when the cultivated land is hard and resistance is applied to the cultivator blade, the combine makes it easy for the operator to control the output and maintain the rotational speed even when the harvest is heavy and the load increases during harvesting operations.

  In the heavy work mode M3, as in the normal work mode M2, the isochronous control that changes the output according to the load at a constant rotation speed even when the load fluctuates, and when the load limit is approached, the rotation speed is increased to increase the output. Control with heavy load control, especially used when farming near the load limit.For example, when plowing with a tractor, engine output even when encountering hard cultivated land Increases beyond the normal limit, so work is not interrupted.

  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.

  Conventionally, in a diesel engine, it is known to perform pilot injection that injects a small amount of fuel in a pulse manner prior to main injection, thereby shortening the ignition delay and reducing the so-called knocking noise peculiar to the diesel engine. .

  This pilot injection is performed once or twice before the main injection. However, by using the system of the common rail 10, the state of the pilot injection is changed according to the state of the engine. The generation of white smoke or black smoke due to noise reduction or incomplete combustion can be suppressed.

  As shown in FIG. 1, when the vehicle is traveling on the road, the injection control mode 1 at the time of fuel injection in the work vehicle equipped with the engine of the common rail 10 is switched to the road mode 1a, so that the accelerator opening is controlled by the operator. By responding quickly to the vehicle so as not to hinder the driving maneuver, it is possible to accurately drive on the road, and when performing work (for example, a field), the accelerator is opened by switching to the work mode 1b. Because it can be made to respond slowly to suppress sudden blow by the calculation correction using the engine ambient temperature, the inertia mass of the vehicle, etc., against the rapid operation of the operator, excessive fuel injection is suppressed, White smoke emission and fuel consumption deterioration can be reduced.

Further, as shown in FIG. 2, the engine speed increase is moderate in the case of the load operation 2b with respect to the rapid accelerator operation 2a, but in the no-load operation 2c, it is in an idling state and the engine speed rapidly increases. Therefore, a threshold value is set for ΔN / Δt, and if this threshold value is equal to or higher than a predetermined reference value, it is determined that the engine is idling and the fuel after the accelerator operation 2a is reached. By controlling the injection amount from the conventional rapid injection amount characteristic 2d to the gentle injection amount characteristic 2e, unnecessary fuel injection can be prevented and black smoke emission can be suppressed for the rapid accelerator operation 2a. Conventionally, the injection timing is often set closer to the retard for Nox countermeasures, but it tends to misfire due to idling due to sudden acceleration when no load is applied, and a large amount of white smoke is easily emitted. Many miracle Therefore, as shown in FIG. 3, the detection of the disconnection by the clutch sensor 3a or the detection of the neutral position by the gear shift position sensor 3b, the cooling water temperature by the water temperature sensor 3c and the intake air temperature by the intake air temperature sensor 3d are both below the set value, When the accelerator operation is suddenly accelerated beyond the set value by the accelerator opening sensor 3e, the engine ECU 18 determines that the engine is idling in a no-load state during low-temperature cooling and advances the fuel injection timing 3f. While misfire and white smoke due to blowing operation can be suppressed, an increase in the combustion noise due to the advance angle can be prevented by increasing the number of pilot injections 3g.

  Further, at low temperatures, the generation of white smoke and startability are also deteriorated due to poor ignition as well as a decrease in ambient temperature, and diesel knock due to poor ignition is also significant. Therefore, an engine using the system of the common rail 10 as shown in FIG. The fuel tank 11, the high-pressure pump 13, the fuel injection valve 17, the ECU 18, the water temperature sensor 3c, the intake air temperature sensor 3d, etc. are connected to each other, and two types of normal rail pressure maps 4a and low-temperature rail pressure maps are connected to the ECU 18. 4b is provided so as to be switchable.

  With such a configuration, as shown in the flowchart of FIG. 7, the ambient temperature is calculated from the cooling water temperature and the intake air temperature. When the temperature is low, the rail pressure is reduced in order to improve white smoke due to misfire and to improve the ignitability at start-up. In addition to switching to the increasing low temperature rail pressure map 4b, control is performed to switch the rail pressure to the normal rail pressure map 4a with priority given to noise when the engine is warmed up.

  Further, in the engine using the system of the common rail 10 as described above, as shown in FIG. 8, the atmosphere temperature is calculated from the cooling water temperature and the intake air temperature by providing the ECU 18 with a single rail pressure map 4 instead of two types. In order to improve white smoke due to misfire at low temperatures and ignitability at start-up, a correction value is calculated to increase the rail pressure and an increase correction is made. Control is performed to reduce the rail pressure.

  In a combined engine governor, the conventional mechanical governor has a decrease in the engine speed even when the engine speed is steady due to the speed fluctuation rate. As shown in Fig. 9, the operation mode of the combine is discriminated, and the engine speed using the common rail 10 is automatically switched and controlled, so that the isochronous control is selected at the time of cutting, threshing and culling discharge, and is rotated at the time of turning. The heavy load control is selected to prevent the decrease in the number and to secure the output, and the droop control is selected to ensure the safety when the brake is operated, so that the appropriate rotation speed control for each work mode is automatically performed. Can be selected and set.

  Further, in the engine of the tractor using the common rail 10, it is determined that the engine speed is to be implemented by lowering the work implement and is automatically switched to isochronous control, and conversely, the work is terminated by raising the work implement. In addition to automatically switching to droop control, when the work equipment rises during turning, switching to droop control automatically switches the engine speed control before work, during work, and during turning. Can work on.

  Further, in the tractor engine using the common rail 10, as shown in FIG. 5, there are provided three kinds of control modes of the traveling mode M 1, the normal working mode M 2, and the heavy working mode M 3 according to the relationship between the rotational speed and the output torque. However, among these, by providing a working depth adjustment dial 5 that automatically switches between the normal working mode M2 and the heavy working mode M3 as working modes according to the working depth state during work, as shown in FIG. For example, the normal operation mode M2 is set up to the level value = 6 of the adjustment dial 5, and the heavy operation mode M3 is set up to the level value = 7 or more, so that the engine speed decreases when the load increases due to the cultivation depth. Can be suppressed.

  In the tractor engine using the common rail 10, the normal work mode M2 and the heavy work mode M3 as the work mode are automatically switched according to the PTO lever position (rotational speed) 6 as shown in FIG. By performing the setting, for example, the normal work mode M2 is set at the first speed position 6a and the second speed position 6b, the heavy work mode M3 is set at the third speed position 6c and the fourth speed position 6d, and the heavy work mode M3 is set at the reverse rotation position 6e. By setting the rotation increase control to the work mode M3, it is possible to suppress a decrease in the engine speed when the load increases.

  Further, in the tractor engine using the common rail 10, the rotation mode control is added to the three kinds of control modes of the traveling mode M1, the normal work mode M2, and the heavy work mode M3 as shown in FIG. By providing the work switching dial 7 that can be switched to an appropriate mode according to the conditions, for example, when traveling on the road 7a is in the traveling mode M1, during plowing 7b is in the normal working mode M2, and in 4WD 7c is the heavy working mode M3. In addition, the automatic work 7d is set to the normal work mode M2 ++ rotation reduction control, and the super full turn 7e is set to the heavy work mode M3 (normal work) + rotation reduction control (turning). Can be implemented.

  In addition, when tilling work on a tractor, conventionally, the vertical movement of the work implement is performed by operating a manual lever when turning the vehicle body at the end of the field, or the vertical angle of the handle is detected automatically. Although there are things to do, for those that operate the manual lever, it is necessary to operate at the same time as the steering wheel operation to turn the car body, so the burden on the operator's arm becomes heavy, and the detection of the turning angle of the steering wheel In the case of automatic up-and-down operation by the operator, there is a problem that the work implement cannot be moved up and down as the operator intends, and there are few things that are operated with the operator's legs when driving the tractor, so the load on the legs is small. The operator's burden can be reduced by moving the work machine up and down by kicking (stepping for a moment). It should be noted that it takes a long time to depress the brake pedal in a normal brake operation, and the operator's will can be determined by the length of the depressing time.

  Further, in the engine using the common rail 10, as shown in FIG. 13, a spring or the like for attaching an urging force is attached to the swirl control plate 9 for intake control provided in the intake port 8, and the balance between the boost pressure and the spring force is provided. By controlling the direction of the control plate 9 mechanically, for example, when the boost pressure is high, the control plate 9 is fully opened a, and as the boost pressure decreases, the control plate 9 is gradually closed by the spring force b. Swirl can be generated. Thus, since the swirl can be controlled with a simple configuration using a spring or the like, it is possible to improve the cost by electric control of a conventional motor or the like and perform control at low cost.

  Further, in the engine using the common rail 10, as shown in FIG. 14, the fuel consumption amount is calculated from signals such as the rail pressure, the number of injections, and the injection time by the ECU 18, and the fuel sensor 23 provided in the fuel tank 11 is used. By linking the detected fuel level, the fuel monitor system 24 can display the fuel consumption rate, the remaining amount of fuel, the estimated fuel replenishment time, and the like. Conventionally, only the remaining amount of fuel was displayed.

  Also, for operations related to the setting of constant speed operation with an electronically controlled engine, conventionally, a switch for setting operation at a constant speed is set regardless of the current operating condition (engine speed) when pressed. However, when the rotational speed is set regardless of the current operating conditions, it is difficult to reflect the operator's will.

  For this reason, as shown in FIG. 15 (a), the engine speed 25b is set by the accelerator operation 25a, and after the accelerator operation 25a is completed, the constant operation mode switch 26 for operating the engine at an arbitrary constant speed is turned ON. When the elapsed time T is greater than the predetermined constant time Ts, the constant operation is performed at the conventional set operation speed. When the elapsed time T is smaller than the predetermined time Ts as shown in FIG. The rotation speed set by the accelerator operation 25a at the time is set as a new operation speed, and the speed of the constant rotation operation mode is determined based on the time interval between the accelerator operation 25a and the mode switch 26. Can be set.

  In addition, as shown in FIG. 16A, when the engine speed 25b is set by the accelerator operation 25a and the operation after the accelerator operation 25a is not performed and the constant operation mode switch 26 is turned ON, When the mode switch 26 is turned on during the accelerator operation 25a as shown in FIG. 16 (b), the engine speed 25b at that time is set to a new set rotation. The constant operation mode can be set according to the relation between the ON state of the mode switch 26 and the accelerator operation 25a.

  Also, in tractors and combines that are equipped with cabins equipped with air conditioning, conventionally, WAX components in the fuel are deposited at low temperatures and the fuel is clogged. Since the problem that the engine output is reduced has occurred, as shown in FIG. 17, an air conditioning duct 27 is arranged to guide around the fuel filter 12 connected to the fuel tank 11, and a fuel temperature sensor. By controlling the temperature by turning the electromagnetic valve 29 on and off by detecting 28, the fuel temperature can be properly controlled. Therefore, the engine can be stopped due to fuel clogging at low temperatures and the output can be reduced at high temperatures. Can be prevented. Even if the fuel pipe in front of the fuel filter 12 is allowed to pass through the air conditioning duct 27, the same effect as described above can be obtained.

  It can be used for general vehicles as well as work vehicles such as tractors and combines.

The diagram which shows the state which can switch an accelerator opening degree to road mode and work mode. The diagram which shows the change state of the engine speed and fuel injection quantity with respect to accelerator operation. The block diagram which shows the idling response | compatibility in the no-load state at the time of the low temperature cooling by ECU. The system figure which shows the pressure accumulation type fuel injection diesel engine by a common rail. The diagram which shows the relationship between the engine speed and output torque by three types of control modes. The system figure which shows the state which provided the rail pressure map for normal and low temperature in ECU. The flowchart figure which shows the procedure which switches a rail pressure map with atmospheric temperature. The system figure which shows the state which provided the rail pressure map which can carry out increase correction in ECU. FIG. 4 is a diagram showing a state of automatic switching of a control mode by discriminating a combine working mode; The top view which shows control mode switching according to the plowing depth state with a plowing depth adjustment dial. The diagram which shows the switching state of a control mode automatically according to a PTO lever position. The top view which shows control mode switching according to the operation | work form with an operation | work switching dial. The top view which shows the action state of the swirl control board provided in the intake port of the engine. The schematic circuit diagram which shows the display state to the monitor of the fuel related information calculated by ECU. (A) The diagram which shows the engine operating speed by mode switch ON after accelerator operation. (B) The diagram which shows the engine operating speed by the mode switch ON after accelerator operation. (A) The diagram which shows the engine operating speed by mode switch ON after accelerator operation. (B) The diagram which shows the engine operating speed by the mode switch ON after accelerator operation. The schematic diagram which shows the state which has arrange | positioned the fuel filter of the engine in the middle of the air-conditioning duct.

Explanation of symbols

1. Injection control mode 1a. Road mode 1b. Working mode

Claims (3)

  In an engine mounted on a work vehicle, an injection control mode (1) at the time of fuel injection is changed from an on-road mode (1a) in road driving in which a temporal response of an accelerator opening responds quickly to an actual operation value, and an actual operation. An engine provided with an injection mode switching device characterized in that it is possible to switch to a work mode (1b) during a work in which the value is corrected and responded gently.   2. The engine according to claim 1, wherein when it is determined that the idling operation is performed from an increase state of the engine speed with respect to the accelerator operation, a response for suppressing the fuel injection amount is performed with respect to an excessive accelerator operation.   At no load, when the intake air temperature and the coolant temperature are below the set value and the accelerator operation speed is above the set value, it is determined that the engine is idling at low temperature cooling, the fuel injection timing is advanced, and the number of pilot injections is set. The engine according to claim 2, wherein the engine is increased.

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