JP2005273541A - Engine output control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an output control device for an engine, simplifying the construction of an intake system and effectively suppressing the hunting of engine rotational speed due to load fluctuation. <P>SOLUTION: The output control device for the engine 1 for controlling the throttle opening of a throttle valve 3 is equipped with a base throttle opening calculation means 13 calculating a base throttle opening vtvopto_base based on a map previously set according to accelerator opening and engine rotational speed, a stabilization correction opening calculation means 14 calculating a stabilization correction opening vtvopto_p performing proportional control on the throttle opening according to change in the base throttle opening vtvopto_base and the engine rotational speed, an integral increase correction opening calculation means 15 calculating an integral increase correction opening vtvopto suppressing fluctuation in the throttle opening when there is a large gradient of change in the stabilization correction opening vtvopto_p, and a target throttle opening output means 17 outputting a target throttle opening vtvoobj to an actuator 4 of the throttle valve 3 according to the base throttle opening vtvopto_base. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in an engine output control device in which a throttle valve is driven by an actuator based on an accelerator operation or the like to electrically control the throttle opening.

  For example, crane trucks and cleaning trucks are equipped with a PTO shaft that enables transmission of engine rotation to an auxiliary device, and the output of the engine is adjusted by operating an accelerator lever when the auxiliary device is activated. .

  However, in the case of a spark ignition engine such as a diesel engine that does not have a governor mechanism that limits the engine rotation speed, if the throttle valve opening is fixed via the accelerator lever during operation of the auxiliary device, the load fluctuation of the auxiliary device Accordingly, the rotational speed of the engine varies greatly, and the rotational speed of the PTO shaft is not stable.

  As countermeasures, Patent Document 1 proposes an engine output control device that stabilizes the rotational speed of the PTO shaft.

  Describing this, as shown in FIG. 6, a main throttle valve 31 and a sub-throttle valve 32 that adjust the intake air amount are interposed in the intake passage 2.

  An accelerator pedal and an accelerator lever (not shown) are mechanically interlocked with the main throttle valve 31 via wires and linkages, respectively. When the accelerator pedal is depressed during traveling of the vehicle, the main throttle valve 31 is opened and the engine output is increased.

While the accelerator lever is pulled in when the auxiliary device is operated, the main throttle valve 31 is maintained in the open state, while a control unit (not shown) is controlled to the amount of operation of the accelerator lever and the engine rotation speed based on a preset map 33. Accordingly, the opening degree of the sub-throttle valve 32 is controlled to keep the engine speed substantially constant.
JP 2001-280174 A

  However, in such a conventional engine output control device, it is necessary to interpose the sub throttle valve 32 along with the main throttle valve 31 in the intake passage 2, and the structure of the intake system becomes complicated. In addition to increasing the cost of the product, there are problems that the layout on the vehicle is difficult.

  Further, as shown in FIG. 7, there is a problem that hunting of the engine speed occurs with respect to a small load fluctuation of the engine and it is difficult to obtain a required load characteristic.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine output control device that simplifies the structure of the intake system and can effectively suppress hunting of the engine speed against load fluctuations. .

  In the present invention, in an engine output control device that includes a throttle valve that adjusts the intake air amount and an actuator that opens and closes the throttle valve, and controls the throttle opening of the throttle valve, the accelerator opening and the engine speed are adjusted. And a basic throttle opening degree calculation means for calculating a basic throttle opening degree vtvopto_base based on a preset map, and a stabilization correction for performing proportional control of the throttle opening degree in accordance with changes in the basic throttle opening degree vtvopto_base and the engine speed. Stabilization correction opening degree calculation means for calculating the opening degree vtvopto_p, and integral increase correction opening for calculating the integral increase correction opening degree vtvtopto that suppresses fluctuations in the throttle opening degree when there is a large gradient in the change of the stabilization correction opening degree vtvopto_p. Degree calculation means and basic And a target throttle opening degree output means for outputting the target throttle opening degree vtvoobj the actuator of the throttle valve in accordance with the throttle opening degree Vtvopto_base.

  According to the present invention, based on the map value of the basic throttle opening degree vtvopto_base, the stabilization correction opening degree vtvopto_p that performs proportional control of the throttle opening degree according to the change of the engine speed is calculated, and this stabilization correction opening degree vtvopto_p When there is a large gradient in the change, the integral increase correction opening degree vtvopto that suppresses fluctuations in the throttle opening is calculated, and this integral increase correction opening degree vtvopto is output as the target throttle opening degree vtvvoj.

  This makes it possible to improve the control response of the throttle opening to changes in engine speed and to prevent the amount of change in the throttle opening from becoming excessive, and effectively hunting the engine speed against engine load fluctuations. Can be suppressed.

  Further, the conventional sub-throttle valve can be eliminated, and the structure of the intake system is simplified, so that the cost of the product can be reduced and the on-vehicle layout becomes easy.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, as the intake valve of each cylinder is opened, the engine 1 sucks the air-fuel mixture into each cylinder from the intake passage 2, compresses the air-fuel mixture with a piston 7, and uses an ignition plug 6. As the exhaust valve is opened, the exhaust gas is discharged to the exhaust passage 9 and these processes are repeated continuously.

  Gas fuel such as CNG and LPG stored in the fuel cylinder is supplied to the intake passage 2 from the fuel injection nozzle 22 through the fuel supply passage 21. The control unit 2 inputs detection signals for various operating conditions, and drives the gas control valve 23 to adjust the amount of fuel injected from the fuel injection nozzle 22 so that the air-fuel mixture reaches the target air-fuel ratio.

  A throttle valve 3 for adjusting the amount of intake air is interposed in the intake passage 2. The throttle valve 3 is opened and closed by an actuator 4. A throttle opening that is the opening of the throttle valve 3 is detected by a throttle opening sensor (not shown). The control unit 10 controls the throttle opening to the target throttle opening by the driving force of the actuator 4.

  A bypass passage 8 that guides intake air by bypassing the throttle valve 3 and an auxiliary intake valve 5 that adjusts the amount of intake air flowing through the bypass passage 8 are provided. The control unit 10 adjusts the opening degree of the auxiliary intake valve 5 to perform feedback control so that the engine speed matches the target idle speed.

  The rotation of the engine 1 is transmitted to wheels via a transmission, a propeller shaft, a differential gear, a drive shaft, etc. (not shown), and is transmitted from the transmission to various auxiliary devices such as an in-vehicle crane via a PTO shaft.

  In order to adjust the output of the engine 1, an accelerator pedal and an accelerator lever (not shown) are provided, respectively, and an accelerator operation amount of the accelerator pedal and the accelerator lever is detected by an accelerator opening sensor (not shown). Further, a PTO switch (not shown) is provided, and is turned on when the auxiliary device driven via the PTO shaft is operated, and is turned off when the auxiliary device is not operated.

  The control unit 10 receives an engine rotation speed signal output from the crank angle sensor 11, an accelerator opening signal output from the accelerator opening sensor, a signal output from the PTO switch, and the like, and drives the throttle valve 3 to open and close. A drive signal is output to the actuator 4 to be operated.

  The control unit 10 includes a travel basic throttle opening calculation means 12 that calculates a travel basic throttle opening vtvoff based on a map set in advance according to the accelerator opening and the engine speed, and according to the accelerator opening and the engine speed. And a basic throttle opening calculation means 13 for calculating a basic throttle opening vtvopto_base based on a preset map, and a stabilization correction for performing proportional control of the throttle opening in accordance with changes in the basic throttle opening vtvopto_base and the engine speed. Stabilization correction opening degree calculation means 14 for calculating the opening degree vtvopto_p, and integral increase correction for calculating the integral increase correction opening degree vtvopto that suppresses fluctuations in the throttle opening degree when there is a large gradient in the change of the stabilization correction opening degree vtvopto_p. Opening calculation means 15; Selection means 16 for selecting the basic throttle opening vtvtopto_base and the running basic throttle opening vtvoff according to the ON / OFF state of the TO switch, and the target throttle opening according to the selected basic throttle opening vtvtopto_base or the running basic throttle opening vtvoff And a target throttle opening output means 17 for outputting the degree vtvobj.

  Next, the control operation executed by the control unit 10 will be described with reference to the flowchart of FIG. This routine is executed at regular intervals.

  First, in steps 1 and 2, the detected values of the engine speed and the accelerator opening are read, and in step 3, it is determined whether the PTO switch is on or off. The processing performed in step 3 corresponds to the selection unit 16.

  When the PTO switch is ON, the routine proceeds to step 4 where a basic throttle opening vtvtopto_base is calculated based on a map 19 set in advance according to the accelerator opening and the engine speed. The processing performed in step 4 corresponds to the basic throttle opening calculation means 13.

  In the following step 5, a stabilization correction opening degree vtvopto_p is calculated according to the basic throttle opening degree vtvopto_base and the engine speed. The processing performed in step 5 corresponds to the stabilization correction opening degree calculation means 14.

  In the following step 6, the integral increase correction opening degree vtvopto is calculated based on the stabilization correction opening degree vtvopto_p. The processing performed in step 6 corresponds to the integral increase correction opening degree calculation means 15.

  On the other hand, when the PTO switch is OFF, the routine proceeds to step 7, where the traveling basic throttle opening vtvoff is calculated based on the map 18 set in advance according to the accelerator opening and the engine speed. The processing performed in step 7 corresponds to the traveling basic throttle opening degree calculation means 12.

  In step 8, the target throttle opening vtvvoj is output in accordance with the selected basic throttle opening vtvopto_base or the traveling basic throttle opening vtvoff. The processing performed in step 8 corresponds to the target throttle opening output means 17.

Next, the structure of the stabilization correction opening degree calculation means 14 is demonstrated based on the (a) figure of FIG. The stabilization correction opening degree calculation means 14 performs proportional control of the throttle opening degree in accordance with changes in the engine speed. More specifically, the difference between the current engine speed (vnn) _n and the engine speed (vnn) _n−1 one cycle before is calculated as ΔN. The stabilization correction opening calculation means 14 inputs ΔN, the basic throttle opening value (vtvopto_base) _n, and the throttle opening proportionality constant KP_TVOPTO at the time of PTO operation as a parameter obtained from the experiment, and based on these, the stabilization correction opening is performed. The degree vtvopto_p is calculated by the following equation.
vtvopto_p = (vtvopto_base) _n −ΔN × KP_TVOPTO (1)
FIG. 3B shows how the map value vtvopto_base and the stabilization correction opening vtvtopto_p of the engine speed and the basic throttle opening change during the operation of the engine 1. When the engine speed fluctuates periodically, the map value vtvtopto_base of the basic throttle opening follows the engine speed with a delay, but by the above processing performed by the stabilization correction opening calculation means 14, The stabilization correction opening degree vtvopto_p compensates for this delay.

  According to the characteristic shown in FIG. 3B, when the engine speed increases, the target throttle opening vtvovoj is corrected to the close side with respect to the map value vtvopto_base of the basic throttle opening, and the engine rotation speed The rise can be suppressed early. On the other hand, when the engine speed decreases, the target throttle opening degree vtvvoj is corrected to the open side with respect to the map value vtvopto_base of the basic throttle opening degree, so that the decrease in engine speed can be suppressed early.

  The integral increase correction opening calculation means 15 is configured to suppress fluctuations in the throttle opening when there is a large gradient in the change of the stabilization correction opening vtvtopto_p.

  The flowchart of FIG. 4A shows a routine for calculating the integral increase correction opening degree vtvtopto, which is executed in the control unit 10 at regular intervals.

This will be explained. First, in step 1, the stabilization correction opening vtvtopto_p is read as A. In the subsequent step 2, the integral increase correction opening degree vtvtopto is set to B and calculated by the following equation. However, (vtvopto) _n−1 is the previous integral increase correction opening degree, and IITVOPTOSTP is the integral increase value.
B = (vtvopto) _n-1 + IITVOPTOSTP (2)
Subsequently, the process proceeds to step 3 to determine whether the stabilization correction opening degree A and the integral increase correction opening degree B are large or small.

Here, if it is determined that A ≧ B, the process proceeds to step 4 where the integral increase correction opening degree (vtvopto) _{n is set} to (vtvopto) _n−1 + IITVOPTOSTP.

On the other hand, when it is determined that A <B, the routine proceeds to step 5 where the integral increase correction opening degree (vtvopto) _n is set as the stabilization correction opening degree (vtvopto_p) _n .

  FIG. 4B shows how the stabilization correction opening degree vtvopto_p and the integral increase correction opening degree vtvtopto change during operation of the engine 1. When the stabilization correction opening degree vtvopto_p does not rise rapidly, the stabilization correction opening degree vtvopto_p is output as it is, and when the stabilization correction opening degree vtvopto_p rapidly rises, the integral increase correction opening degree that increases proportionally with the passage of time. replaced by vtvopto.

  When the operating region is located where the slope of the map value vtvopto_base of the basic throttle opening is large, the slope of the stabilization correction opening vtvopto_p also increases. However, as shown in FIG. By replacing the rapidly increasing portion of the correction opening degree vtvopto_p with the integral increase correction opening degree vtvopto, it is possible to suppress an excessive change amount of the throttle opening degree. By performing the integral increase correction of the throttle opening in this way, it is possible to prevent the throttle valve 3 from opening abruptly and to suppress the load fluctuation of the engine 1.

  As described above, when the PTO switch is turned ON during the operation of the auxiliary device, the stabilization correction opening vtvtopto_p that performs proportional control of the throttle opening according to the change in the engine speed based on the map value of the basic throttle opening vtvtopto_base. Is calculated, and when there is a large gradient in the change of the stabilization correction opening vtvopto_p, an integral increase correction opening vtvopto that suppresses the fluctuation of the throttle opening is calculated. The target throttle opening degree output means 17 outputs the target throttle opening degree vtvobj. Thereby, at the time of the operation of the auxiliary device, it is possible to improve the control response of the throttle opening with respect to the engine speed change and to prevent the change amount of the throttle opening from becoming excessive, and against the load fluctuation of the auxiliary device. The engine speed hunting can be effectively suppressed.

  On the other hand, when the PTO switch is turned off when the auxiliary device is not operated, the basic driving throttle opening vtvoff calculated according to the accelerator opening and the engine speed is selected by the basic driving throttle opening calculation means 12 based on the map. The target throttle opening degree output means 17 outputs the target throttle opening degree vtvoobj through the means 16. Thereby, when the vehicle is traveling, the throttle opening is controlled in accordance with the map value of the traveling basic throttle opening vtvoff, so that the responsiveness of the output control of the engine 1 can be ensured.

  The selection means 16 can automatically switch the output control when the auxiliary device is in operation and when it is not in operation by selecting the basic throttle opening vtvtopto_base and the traveling basic throttle opening vtvoff according to ON / OFF of the PTO switch.

  In addition, since the conventional sub-throttle valve can be eliminated to simplify the structure of the intake system, the cost of the product can be reduced and the layout on the vehicle can be facilitated.

  Next, an embodiment applied to a vehicle without a PTO shaft will be described. In addition, the same code | symbol is attached | subjected to the same structure part as the said embodiment.

  As shown in FIG. 5, the control unit 10 includes a basic throttle opening degree calculation means 13 for calculating a basic throttle opening degree vtvtopto_base based on a map set in advance according to the accelerator opening degree and the engine speed, and the basic throttle opening degree. There is a large gradient in the stabilization correction opening degree calculation means 14 for calculating the stabilization correction opening degree vtvopto_p that performs proportional control of the throttle opening degree according to the change in vtvtopto_base and the engine speed, and the change in the stabilization correction opening degree vtvopto_p. Integral increase correction opening degree calculating means 15 for calculating an integral increase correction opening degree vtvopto that suppresses fluctuations in the throttle opening amount, and target throttle opening degree output means for outputting the target throttle opening degree vtvvoj according to the basic throttle opening degree vtvopto_base With 17 .

  That is, the control unit 10 shown in FIG. 5 has a configuration in which the traveling basic throttle opening calculation means 12 and the selection means 16 are not provided from the configuration of the control unit 10 shown in FIG.

  In this case, when the vehicle is running, it is possible to improve the control response of the throttle opening with respect to the engine speed change and to prevent the change amount of the throttle opening from becoming excessive, and the engine speed with respect to the load fluctuation is reduced. Hunting can be effectively suppressed.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The engine output control device of the present invention can be applied to a vehicle including a PTO shaft that can transmit the rotation of the engine to an auxiliary device, such as a crane truck or a cleaning car, and is not limited thereto, and does not include a PTO shaft. It can also be applied to vehicles.

1 is a system diagram of an engine output control apparatus showing an embodiment of the present invention. The flowchart which similarly shows control operation. Similarly, (a) is a block diagram of the stabilization correction opening degree calculation means, (b) is a characteristic diagram showing each control value. Similarly, (a) is a flowchart showing a routine for calculating the integral increase correction opening degree vtvopto, and (b) is a characteristic diagram showing each control value. The system figure of the engine output control apparatus which shows other embodiment of this invention. The block diagram which shows a prior art example. The control characteristic figure of a conventional example similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 3 Throttle valve 4 Actuator 10 Control unit 12 Travel basic throttle opening calculation means 13 Basic throttle opening calculation means 14 Stabilization correction opening calculation means 15 Integral increase correction opening calculation means 16 Selection means 17 Target throttle Opening output means

Claims (4)

A throttle valve for adjusting the amount of intake air;
An actuator for opening and closing the throttle valve,
In the engine output control device that controls the throttle opening of the throttle valve,
Basic throttle opening degree calculation means for calculating a basic throttle opening degree vtvtopto_base based on a map set in advance according to the accelerator opening degree and the engine speed;
Stabilization correction opening degree calculation means for calculating a stabilization correction opening degree vtvopto_p for performing proportional control of the throttle opening degree according to a change in the basic throttle opening degree vtvopto_base and the engine rotation speed;
An integral increase correction opening degree calculation means for calculating an integral increase correction opening degree vtvopto that suppresses fluctuations in the throttle opening degree when there is a large gradient in the change of the stabilization correction opening degree vtvopto_p;
An engine output control device comprising target throttle opening degree output means for outputting a target throttle opening degree vtvvoj to an actuator of the throttle valve in accordance with a basic throttle opening degree vtvoptto_base. The stabilization correction opening degree calculation means calculates the difference between the current engine speed (vnn) _n and the engine speed (vnn) _n−1 before one execution cycle as ΔN, and this ΔN and the basic throttle opening value 2. The stabilization correction opening degree vtvopto_p is calculated as vtvtopto_p = (vtvopto_base) _n− ΔN × KP_TVOPTO based on (vtvopto_base) _n and a preset throttle opening proportionality constant KP_TVOPTO during PTO operation. The engine output control device described. The integral increase correction opening calculation means calculates an integral increase correction opening vtvtopo = (vtvopto = () based on a preset integral increase value IITVOPTOSTP and an integral increase correction opening (vtvopto) _n−1 one execution cycle before. vtvtopto) _n-1 + IITVOPTOSTP, and when the correction correction opening vtvopto_p is greater than or equal to the integral increase correction opening vtvtopto, the integral increase correction opening (vtvopto) _{n is set} to (vtvopto) _n-1 + IITVOPTPOSTP 3. The engine according to claim 1, wherein when the opening vtvtopto_p is smaller than the integral increase correction opening vtvtopto, the integral increase correction opening (vtvopto) _n is set as the stabilization correction opening (vtvopto_p) _n . Output control device. Traveling basic throttle opening calculating means for calculating a traveling basic throttle opening vtvoff based on a map set in advance according to the accelerator opening and the engine speed;
A PTO switch that switches between activation and deactivation of an auxiliary device driven by the engine;
Selecting means for selecting a basic throttle opening vtvtopto_base and a traveling basic throttle opening vtvoff according to a signal from the PTO switch;
4. The target throttle opening degree output means is configured to output a target throttle opening degree vtvvoj in accordance with the selected basic throttle opening degree vtvopto_base or the traveling basic throttle opening degree vtvoff. The engine output control device according to one.

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