JP2007263012A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent drop of load and overturn of a vehicle at a time of quick acceleration or quick deceleration of an industrial vehicle performing cargo work. <P>SOLUTION: In this engine control device, throttle opening is controlled not to change according to operation quantity but to change smaller than the same when accelerator opening change quantity, namely operation quantity of an acceleration pedal by a driver is larger than a predetermined value. Consequently, inertia force acting on the industrial vehicle at a time of quick acceleration and deceleration can be kept small and drop of load and turnover of the vehicle can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control apparatus, and more particularly to an engine control apparatus that performs throttle control suitable for stable running of an industrial vehicle that performs a cargo handling operation.

  In an industrial vehicle that performs a cargo handling operation such as a forklift, the load position of the load is at a position away from the center of gravity of the vehicle. Therefore, the moment applied to the vehicle changes depending on the weight of the load. In addition, the moment applied to the vehicle also varies greatly depending on the lift height of the load caused by raising and lowering the fork. For this reason, especially when a heavy load is lifted high, the moment applied to the vehicle becomes large, and the traveling of the vehicle becomes unstable.

  Conventionally, such an industrial vehicle has used a mechanical throttle (hereinafter referred to as “mechanical throttle”) that is interlocked with the depression of the accelerator pedal (accelerator operation) by the driver. However, since this mechanical throttle moves according to the driver's accelerator operation, if the accelerator is operated suddenly while the vehicle is carrying a heavy load, the drop in the load or the There is a risk of overthrow. In particular, when such a sudden accelerator operation is performed while the vehicle is turning, the risk increases.

  FIG. 11 is an explanatory diagram showing problems at the time of sudden acceleration and deceleration of a vehicle when a mechanical throttle is employed in a forklift. (A) represents the case where the vehicle has suddenly returned the throttle from the steady running state. (B) represents a case where the vehicle has suddenly returned the throttle from the acceleration state. In (A) and (B), the horizontal axis represents time, and the vertical axis represents the accelerator opening, the actual throttle opening (referred to as “actual throttle opening”), and the acceleration of the vehicle from the top. (C) represents the lateral force applied to the load when the vehicle starts suddenly with a large steering angle. The horizontal axis represents time, and the vertical axis represents the accelerator opening, the actual throttle opening, and the lateral acceleration (referred to as “lateral G”) applied to the load from the top. Furthermore, (D) represents the forward force applied to the load when the vehicle suddenly starts to reverse in a forward tilt state. The horizontal axis represents time, and the vertical axis represents the accelerator opening, the actual throttle opening, and the forward inertial force applied to the load from the top.

In the figure, the state quantity such as the accelerator opening changes in a step shape because the result of sampling at a constant cycle is shown (the same applies hereinafter).
As shown in FIG. 5A, the accelerator pedal opening degree is increased by depressing the accelerator pedal almost constantly and releasing the foot from the accelerator pedal while the vehicle is in a steady running state, or by quickly returning the pedal without releasing the foot. When it decreases rapidly, the actual throttle opening also decreases at the same rate in conjunction with the accelerator opening. At this time, the negative acceleration increases due to the rapid throttle operation, and the possibility that the load on the fork falls due to its inertial force increases.

  Furthermore, as shown in FIG. 5B, when the accelerator opening decreases rapidly from the state where the vehicle is accelerated by depressing the accelerator pedal, the load on the fork has a larger inertial force. Works. For this reason, the possibility that the load will fall further increases.

Further, as shown in FIG. 5C, when the vehicle starts suddenly with the steering wheel turned largely off, the lateral G becomes large and the possibility of the load falling increases.
Furthermore, as shown in FIG. 4D, when the vehicle suddenly starts to back in a forward tilt state, inertial force in the forward direction is applied to the load as compared to when the vehicle is traveling on flat ground. For this reason, the possibility of the load falling increases.

  By the way, as a technology for preventing a cargo collapse, a cargo drop, and a fall accident when turning a cargo handling vehicle, for example, a vehicle speed control device that controls the vehicle speed by changing the speed at which the throttle is closed according to the turning state of the vehicle and the vehicle speed is proposed. (For example, refer to Patent Document 1).

This vehicle speed control device sets a limit vehicle speed according to the steering angle, and when the current vehicle speed exceeds the limit vehicle speed, the difference between the current vehicle speed and the limit vehicle speed and the limit vehicle speed are exceeded. The speed at which the throttle is closed is changed based on the time. Thus, the vehicle speed is gradually reduced without giving a shock to the vehicle.
Japanese Patent No. 2842875

  However, although the technique described in the above cited document 1 can solve to some extent the problem of preventing load collapse due to centrifugal force during turning of a cargo handling vehicle, unloading and falling accidents, the vehicle is suddenly accelerated and suddenly decelerated. It has not been possible to prevent a large inertial force from being instantaneously applied to the vehicle and the load from falling or the body from being overturned.

Such a problem may occur not only with a forklift but also with other industrial vehicles as long as the vehicle performs a cargo handling operation.
The present invention has been made in view of the above points, and is an engine control device capable of preventing a drop of a load and an overturn of the vehicle at the time of sudden acceleration and sudden deceleration of an industrial vehicle performing a cargo handling operation. The purpose is to provide.

  In order to solve the above problems, the present invention is an engine control device that controls an engine mounted on an industrial vehicle that performs a cargo handling operation, and changes the opening of a throttle valve based on the detected accelerator opening. Throttle control amount calculation means for calculating a control amount, throttle valve control means for controlling a throttle valve based on the control amount calculated by the throttle control amount calculation means, and the throttle control amount calculation means, An engine control device is provided, comprising: a reduction correction unit that reduces the control amount to be calculated when the amount of change in the accelerator opening is greater than a predetermined value.

  According to such an engine control device, when the accelerator opening change amount, that is, the amount of operation of the accelerator pedal by the driver is larger than a predetermined value, the throttle opening does not change at a rate corresponding to the operation amount. , It is controlled to change at a smaller rate.

  According to the engine control apparatus of the present invention, when the accelerator opening change amount is larger than a predetermined value, the throttle opening change amount is controlled to be small. For this reason, it is possible to reduce the inertial force applied to the industrial vehicle at the time of rapid acceleration / deceleration, and it is possible to prevent the load from falling or the vehicle from overturning.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the engine control device of the present invention is applied to a forklift (corresponding to an “industrial vehicle”). FIG. 1 is a schematic configuration diagram showing the overall configuration of the forklift according to the present embodiment.

  The forklift 1 includes a mast 2 erected so as to extend vertically in front of the vehicle, a fork 3 provided so as to be movable up and down along the mast 2, and driving up and down of the fork 3 or swinging the mast 2 in the front-rear direction. A predetermined drive mechanism or the like is provided. The driver operates the vehicle 4 and loads the cargo on the fork 3 by operating the steering 4 and the operation lever 5 provided in front of the driver's seat. Various parts to be described later for engine control are disposed in each part of the vehicle, and an engine 6 and an electronic control unit (hereinafter referred to as “ECU”) 7 for controlling the engine 6 are provided inside the vehicle. Is provided. In the present embodiment, the ECU 7 constitutes an engine control device.

FIG. 2 is a block diagram showing the ECU and its input / output.
The ECU 7 includes a CPU (Central Processing Unit) that executes various arithmetic processes, a ROM (Read Only Memory) that stores various control arithmetic programs and data, and a RAM (Random Access) that stores numerical values and flags of arithmetic processes in a predetermined area. Memory), A / D (Analog / Digital) converter that converts an input analog signal into a digital signal, an input / output interface for inputting / outputting various digital signals, and a bus line to which each of these devices is connected. ing.

  The ECU 7 takes in output signals from various sensors that detect the state of the vehicle including the engine 6 and calculates control amounts for engine control, and outputs drive signals based on the control amounts to various actuators provided in the engine 6. Output.

  That is, the ECU 7 includes an engine speed sensor 11 that detects the engine speed, an accelerator opening sensor 12 that detects the amount of operation of the accelerator pedal by the driver, and a throttle opening sensor 13 that detects an electronic throttle opening, which will be described later. A steering angle sensor 14 for detecting the turning angle of the steering wheel 4, a load sensor 15 for detecting the weight of the load loaded on the fork 3, a lift height sensor 16 for detecting the lift height of the fork 3, and the horizontal direction of the vehicle Sensors and switches such as a tilt sensor 17 for detecting a tilt with respect to the gear, a shift position sensor 18 for detecting a current shift position by the transmission, an ignition switch 19, and a power steering switch 20 for driving a hydraulic pump of the power steering are connected. .

  The ECU 7 includes an injector 21 provided for each cylinder for supplying fuel, a fuel pump 22 for pumping fuel from the fuel tank and supplying the fuel to the injector 21, an igniter 23 for generating high voltage for ignition for each cylinder, Various actuators such as an electronic throttle 24 for adjusting the amount of intake air by controlling the opening of the throttle valve not to be operated and a starter motor 25 for cranking the engine 6 are connected. The ECU 7 performs predetermined control calculation processing according to a control program stored in the ROM.

  Next, the engine control method of the present embodiment will be described. This engine control method is characterized by throttle opening control based on the accelerator opening (referred to as “throttle control”). Therefore, only the throttle control will be described here, and description of other controls such as fuel injection control and ignition timing control will be omitted.

  FIG. 3 is an explanatory diagram showing an outline of the throttle control in the case of deceleration of the vehicle. In the figure, the horizontal axis represents time, and the vertical axis represents the accelerator opening, the accelerator opening change amount, and the actual throttle opening from the top.

  This throttle control roughly calculates the accelerator opening change amount, and if the change amount is larger than a preset throttle change limit value (corresponding to “predetermined value”), the throttle opening control is performed. The amount is limited to the throttle change amount limit value, and is changed. The throttle change amount limit value is set as a change amount of the throttle opening that exceeds this value, the possibility of drop of the load or rollover of the vehicle increases. That is, the throttle change amount limit value is a limit value of the change amount of the throttle opening set in order to ensure stable vehicle travel and safe cargo handling work, and is set as appropriate according to the state of the vehicle.

  Here, since “the amount of change in throttle opening” and “the amount of change in accelerator opening” are compared as the ratio of each control amount (that is, the ratio to the maximum control amount:%), both are directly It corresponds. However, when comparing the two as the absolute values of the control amounts, when the accelerator opening change amount is larger than the change amount corresponding to the throttle change limit value, the throttle opening control amount is set to the throttle change limit value. It will be changed and limited to the value.

  Here, if the amount of change in the accelerator opening is equal to or less than the limit value for changing the throttle, as in the case of steady running of the vehicle, it is linked to the accelerator opening (that is, corresponding to the rate of change in the accelerator opening). ) Throttle control using the throttle opening as the target control amount is performed. For this reason, the actual throttle opening changes in accordance with the depression amount of the accelerator pedal by the driver.

  On the other hand, when the accelerator opening change amount exceeds the throttle change amount limit value due to sudden deceleration of the vehicle, throttle control is performed with the throttle opening amount that uses the throttle change amount limit value as the change amount as the target control amount. For this reason, as shown in the figure, the actual throttle opening decreases at a rate smaller than the accelerator opening change amount. However, in order to finally realize a throttle opening corresponding to the amount of accelerator pedal operation by the driver, the throttle opening remains within the throttle change limit even after the accelerator opening has converged to a constant value such as zero. It decreases with the amount of change corresponding to the value. That is, the actual throttle opening continues to change up to the throttle opening corresponding to the total change in the accelerator opening. In this way, the change amount of the actual throttle opening is guarded by the throttle change amount limit value, thereby preventing a sudden change in the behavior of the vehicle due to sudden deceleration.

  In the figure, the throttle control at the time of sudden deceleration of the vehicle is shown. However, at the time of sudden acceleration, basically the same control is performed except that the direction of change of the accelerator opening and the throttle opening is reversed. Is done. For this reason, the description of the throttle control during sudden acceleration of the vehicle is omitted.

Next, the flow of the throttle control process of the present embodiment will be described.
FIG. 4 is a flowchart showing the overall flow of the throttle control process executed by the ECU. This process is repeated until the engine 6 starts and then stops. Hereinafter, the flow of this process will be described using step numbers (hereinafter referred to as “S”).

  The ECU 7 first calculates the current accelerator opening based on the input signal from the accelerator opening sensor 12 (S1). Subsequently, the accelerator opening change amount is calculated using the previously calculated accelerator opening value (S2), and it is determined whether the change amount is positive or negative (S3). At this time, if the accelerator opening change amount is negative, a deceleration time process described later is executed (S4), and if the accelerator opening change amount is positive, an acceleration process described later is executed (S5). If the amount of change in accelerator opening is zero, the process is terminated as it is.

  FIG. 5 is a flowchart showing a flow of deceleration processing executed in throttle control. FIG. 6 is an explanatory diagram showing a control map used for deceleration processing. (A) is a control map used when the vehicle suddenly decelerates from steady running. (B) is a control map used when the vehicle suddenly decelerates from the acceleration state. In each figure, the horizontal axis represents the accelerator opening change amount, and the vertical axis represents a guard value (referred to as a “basic guard value”) that serves as a base for calculating the throttle change limit value. Further, FIG. 7 is a correction map for calculating a correction coefficient for correcting the basic guard value in order to calculate the throttle change limit value according to the state of the vehicle. (A) represents a product load term coefficient K1, which is a correction coefficient using the weight of the load as a parameter. (B) represents a lift height term coefficient K2, which is a correction coefficient using the lift height of the fork 3 as a parameter. Further, (C) represents an inclination term coefficient K3 that is a correction coefficient using the inclination angle of the vehicle body as a parameter.

As shown in FIG. 5, in the deceleration time process, first, based on the input signal from the product load sensor 15, it is determined whether or not there is a current load (S11).
At this time, if it is determined that there is a load (S11: YES), it is then determined whether or not the previous accelerator opening change amount is positive (S12). At this time, if the previous accelerator opening change amount is zero or negative (S12: NO), the basic guard value 1 is calculated based on the control map of FIG. 6A (S13). The basic guard value 1 is a guard value when the vehicle decelerates from steady running or further decelerates from the decelerated state, and decreases as the accelerator opening change amount increases. This is because the degree of sudden deceleration increases as the amount of change in accelerator opening increases, so the basic guard value is reduced to further limit the amount of change in throttle opening so that the shock to the vehicle does not increase. Is. Thereby, the fall of a load and the overturn of a vehicle are prevented.

  On the other hand, if the previous accelerator opening change amount is positive (S12: YES), the basic guard value 2 is calculated based on the control map of FIG. 6B (S14). This basic guard value 2 is a guard value when the vehicle suddenly decelerates from the acceleration state. In this case, since the inertial force applied to the vehicle is further increased, it is necessary to make the basic guard value stricter in order to prevent the load from falling or the vehicle from overturning. For this reason, as shown in the figure, the basic guard value 2 is set smaller than the basic guard value 1 with respect to the accelerator opening change amount, and the throttle change amount limit value is further limited.

  Subsequently, the basic guard value calculated as described above is corrected based on the state of the vehicle. This is because the inertial force applied to the vehicle and its load changes not only due to the deceleration, but also changes depending on the loading condition of the load on the fork 3 and the traveling environment of the vehicle.

  First, the weight of the current load is calculated based on the input signal from the product load sensor 15, and the product load term coefficient K1 is calculated using the correction map of FIG. 7A (S15). Since the traveling of the vehicle becomes unstable as the weight of the load increases, the product load term coefficient K1 decreases as the weight of the load increases, so that the basic guard value is corrected to be smaller to further limit the throttle change amount limit value. I have to.

  Subsequently, the current lift height of the fork 3 is calculated based on the input signal from the lift height sensor 16, and the lift height term coefficient K2 is calculated using the correction map of FIG. . Since the vehicle travel becomes more unstable as the lift height of the fork 3 becomes higher, the lift height term coefficient K2 becomes smaller as the lift height of the fork 3 becomes higher. The limit value is more limited.

  Further, the current inclination angle of the vehicle body is calculated based on the input signal from the inclination sensor 17, and the inclination term coefficient K3 is calculated using the correction map shown in FIG. Since the traveling of the vehicle becomes unstable as the vehicle body inclination angle increases, the inclination term coefficient K3 decreases as the vehicle body inclination angle increases, and the basic guard value is corrected to be smaller to further limit the throttle change amount limit value. I am doing so.

  Then, a throttle change amount limit value is calculated (S18). This throttle change limit value is calculated from the following equation (1) using the product load term coefficient K1, the lift height term coefficient K2, and the tilt term coefficient K3.

Throttle change limit value = basic guard value (1 or 2) × K1 × K2 × K3 (1)
Subsequently, it is determined whether or not the accelerator opening change amount is equal to or greater than the throttle change amount limit value during deceleration (S19). At this time, if the accelerator opening change amount is equal to or larger than the throttle change amount limit value (S19: YES), the throttle opening target control amount (referred to as "throttle opening control amount") is set as the throttle change amount limit value. (S20), and the electronic throttle is driven (energized) so as to achieve the target control amount (S22).

  On the other hand, when it is determined in S11 that there is no load (S11: NO) and when it is determined in S19 that the accelerator opening change amount is smaller than the throttle change limit value (S19: NO), throttle opening control is performed. The amount is set to be the amount of change in the throttle opening corresponding to the current accelerator opening (S21), and the electronic throttle is driven (energized) to realize the target control amount (S22).

  FIG. 8 is a flowchart showing the flow of acceleration processing executed in throttle control. Moreover, FIG. 9 is explanatory drawing showing the control map used for the process at the time of acceleration. (A) is a control map used when the vehicle is accelerated when the steering is off in the R range (back). (B) is a control map used when the vehicle accelerates when the steering is not cut in the R range. In both figures, the horizontal axis represents the accelerator opening change amount, and the vertical axis represents the basic guard value. Furthermore, (C) is a control map used when the vehicle starts straight and the vehicle is abruptly started when the steering is cut off. In the figure, the horizontal axis represents the tilt angle of the vehicle body, and the vertical axis represents the basic guard value. Further, FIG. 10 is a correction map for calculating a correction coefficient for correcting the basic guard value in order to calculate the throttle change limit value according to the state of the vehicle. (A) represents a product load term coefficient K4, which is a correction coefficient using the weight of the load as a parameter. (B) represents an inclination term coefficient K5, which is a correction coefficient using the inclination angle of the vehicle body as a parameter.

As shown in FIG. 8, in the acceleration process, first, based on the input signal from the product load amount sensor 15, it is determined whether or not there is a current load (S31).
At this time, if it is determined that there is a load (S31: YES), it is then determined whether the current shift position is in the R range (back) based on the input signal from the shift position sensor 18 (S32). ). At this time, if it is determined that the shift position is in the R range (S32: YES), it is subsequently determined whether or not there is a steering angle based on an input signal from the steering angle sensor 14 (S33). At this time, if it is determined that there is a steering angle (S33: YES), a basic guard value 3 is calculated based on the control map of FIG. 9A (S34). This basic guard value 3 is a guard value when the vehicle is moving backward and accelerating with the steering turned off, and decreases as the accelerator opening change amount increases. This is because the degree of rapid acceleration increases as the amount of change in accelerator opening increases, and the centrifugal force applied to the vehicle increases, so the basic guard value is reduced to further limit the amount of change in throttle opening. This prevents the vehicle from falling or overturning the vehicle.

  On the other hand, when it is determined in S33 that there is no steering turning angle (S33: NO), the basic guard value 4 is calculated based on the control map of FIG. 9B (S35). This basic guard value 4 is a guard value when the vehicle is accelerating in a straight line in the rear direction. However, since the steering is not turned off, the risk of falling of the load or rollover of the vehicle is reduced. The value is more moderate.

  If it is determined in S32 that the shift position is not in the R range (S32: NO), it is subsequently determined whether or not there is a steering turning angle (S36). At this time, if it is determined that there is a steering angle (S36: YES), a basic guard value 5 is calculated based on the control map of FIG. 9C (S37). This basic guard value 5 is a guard value when the vehicle is accelerating with the steering turned off, but since it is forward, the possibility that the load is supported by the fork 3 from the rear and falls is small, The guard value is further increased to make the throttle change limit value more gradual.

  Subsequently, the basic guard value calculated as described above is corrected based on the state of the vehicle. This is in consideration of changes depending on the loading condition of the load on the fork 3 and the traveling environment of the vehicle, as in the deceleration process.

  First, the weight of the current load is calculated based on the input signal from the load sensor 15, and the reverse load product coefficient K4 is calculated using the correction map of FIG. 10A (S38a). Similarly, the product load term coefficient K4 at the time of forward movement is calculated (S38b). It should be noted that the product load term coefficient K4 during forward travel and reverse travel may be calculated using the same correction map. In this case, if the weight of the load becomes too large, the possibility of the vehicle overturning due to the centrifugal force increases, so the product load term coefficient K4 basically increases as the weight of the load increases. When it exceeds, it tries to become small.

  Subsequently, the current inclination angle of the vehicle body is calculated based on the input signal from the inclination sensor 17, and the inclination term coefficient K5 is calculated using the correction map of FIG. Since the influence of the inertial force applied to the vehicle increases as the vehicle body inclination angle increases, the inclination term coefficient K5 decreases as the vehicle body inclination angle increases, so that the basic guard value is corrected to a smaller value and the throttle change amount limit value is further increased. I try to limit it.

Then, a throttle change limit value is calculated (S40). This throttle change amount limit value is calculated from the following equation (2) using the product load term coefficient K4 and the inclination term coefficient K5.
Throttle change limit value = basic guard value (3, 4 or 5) × K4 × K5 (2)
Subsequently, it is determined whether or not the accelerator opening change amount is equal to or greater than the throttle change amount limit value during deceleration (S41). At this time, if the accelerator opening change amount is equal to or greater than the throttle change amount limit value (S41: YES), the throttle opening control amount is set to be a change amount corresponding to the throttle change amount limit value ( In step S42, the electronic throttle is driven (energized) so as to realize the target control amount (S44).

  On the other hand, when it is determined that there is no load in S31 (S31: NO), when it is determined that there is no steering turning angle in S36 (S36: NO), and in S41, the accelerator opening change amount is greater than the throttle change amount limit value. Is determined to be small (S41: NO), the throttle opening control amount is set to be the amount of change in the throttle opening corresponding to the current accelerator opening (S43), and the target control amount is realized. Then, the electronic throttle is driven (energized) (S44).

  As described above, according to the engine control apparatus of the present embodiment, when the accelerator opening change amount, that is, the accelerator pedal operation amount by the driver is larger than the throttle change amount limit value, the throttle opening amount Is controlled so as not to change according to the operation amount, but to change with a throttle change amount limit value smaller than that. For this reason, it is possible to reduce the inertial force applied to the industrial vehicle at the time of rapid acceleration / deceleration, and it is possible to prevent the load from falling or the vehicle from overturning.

  In the above embodiment, as shown in FIG. 3, when the accelerator opening change amount is larger than the throttle change amount limit value, instead of changing the throttle opening control amount, the accelerator opening amount is Even after convergence to zero, etc., the change in the throttle opening is continued. However, when the unintentional change in throttle opening gives the driver a sense of incongruity, that is, when the change-over time is long enough to be experienced, the accelerator opening converges to zero etc. almost simultaneously. Changes in the throttle opening may be converged.

  Further, in the above embodiment, the throttle change amount limit value is the limit value of the change amount of the throttle opening set in order to ensure stable vehicle driving and safe cargo handling work, but the limit value is Further, it may be a limit value at which the load does not drop or the vehicle overturns, or may be a limit value obtained by multiplying the limit value by a predetermined safety factor.

  In the above embodiment, the example in which the presence or absence of the steering angle is determined based on the input signal from the steering angle sensor 14 is shown in FIG. 8, but depending on whether or not the power steering switch 20 is turned on. You may make it judge. That is, since the power steering switch 20 is automatically turned on when the steering is turned by a predetermined minute angle, it is determined that there is a steering turning angle based on the output signal. In this way, it is possible to reduce the cost by omitting the steering angle sensor 14.

  Further, in the above-described embodiment, an example in which the engine control device of the present invention is applied to a forklift has been shown. However, the present invention can also be applied to other industrial vehicles other than a forklift that performs a cargo handling operation.

It is a schematic structure figure showing the whole forklift truck composition of an embodiment. It is a block diagram showing ECU and its input-output. It is explanatory drawing showing the outline of throttle control taking the time of deceleration of a vehicle as an example. It is a flowchart showing the whole flow of the throttle control processing which ECU performs. It is a flowchart showing the flow of the process at the time of deceleration performed in throttle control. It is explanatory drawing showing the control map used for the process at the time of deceleration. It is a correction map for calculating a correction coefficient for correcting the basic guard value in order to calculate a throttle change amount limit value according to the state of the vehicle. It is a flowchart showing the flow of the process at the time of acceleration performed in throttle control. It is explanatory drawing showing the control map used for the process at the time of acceleration. It is a correction map for calculating a correction coefficient for correcting the basic guard value in order to calculate a throttle change amount limit value according to the state of the vehicle. It is explanatory drawing showing the problem at the time of the sudden acceleration of a vehicle at the time of employ | adopting a mechanical throttle in a forklift, and a sudden deceleration.

Explanation of symbols

1 Forklift 3 Fork 4 Steering 6 Engine 7 ECU
12 Accelerator opening sensor 14 Steering angle sensor 15 Load sensor 16 Lift height sensor 17 Tilt sensor 18 Shift position sensor 24 Electronic throttle

Claims (8)

An engine control device that controls an engine mounted on an industrial vehicle that performs a cargo handling operation, and a throttle control amount calculation unit that calculates a control amount for changing the opening of a throttle valve based on a detected accelerator opening; ,
Throttle valve control means for controlling the throttle valve based on the control amount calculated by the throttle control amount calculation means;
The throttle control amount calculating means, when the change amount of the accelerator opening during a predetermined time is larger than a predetermined value, a decrease correction means for correcting the calculated control amount to decrease;
An engine control device comprising:   2. The engine control apparatus according to claim 1, wherein the reduction correction means changes the correction of the control amount according to the direction of change of the accelerator opening.   The decrease correction means corrects the amount of change in the control amount to be smaller when the accelerator opening changes from positive to negative than when the accelerator opening changes from negative to negative. The engine control device according to claim 2. Shift position detecting means for detecting the shift position of the industrial vehicle,
3. The engine control apparatus according to claim 2, wherein the throttle control amount calculation means changes the correction of the control amount depending on whether or not the shift position is in an R range. A steering angle detecting means for detecting a steering angle of the industrial vehicle;
3. The engine control apparatus according to claim 2, wherein when the change in the accelerator opening is positive, the reduction amount correction means changes the change amount of the control amount in accordance with the steering angle. . The industrial vehicle is a forklift;
A lift height detecting means for detecting a lift height of the fork of the forklift,
2. The engine control apparatus according to claim 1, wherein the throttle control amount calculation means changes a change amount of the control amount in accordance with the lift height.   2. The engine control apparatus according to claim 1, wherein the throttle control amount calculation means changes the correction of the control amount according to an inertial force applied to a load of the industrial vehicle. An engine control device that controls an engine mounted on an industrial vehicle that performs a cargo handling operation, and a throttle control amount calculation unit that calculates a control amount for changing the opening of a throttle valve based on a detected accelerator opening; ,
Throttle valve control means for controlling the throttle valve based on the control amount calculated by the throttle control amount calculation means,
The engine control device according to claim 1, wherein the throttle control amount calculation means limits a control amount to be calculated when a change amount of the accelerator opening during a predetermined time is larger than a predetermined value.

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