JP4500761B2 - Engine output control device - Google Patents

Description

  The present invention relates to an improvement in an engine output control device that controls a throttle opening by driving a throttle valve with an actuator based on an accelerator operation or the like.

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

To explain this, as shown in FIGS. 4A and 4B, a basic throttle opening vtvtopto_base is calculated based on a map M set in advance according to the accelerator opening and the engine speed vnn. The intake air amount is adjusted by controlling the throttle opening of the throttle valve based on the map value of the opening vtvopto_base.
JP 2005-273541 A

  However, in such a conventional engine output control device, as shown in FIG. 4 (a), when the PTO switch is turned on during operation of the auxiliary device, the working accelerator opening vapstopper is stepped. After the increase, the value is maintained at a predetermined value, and the map value of the throttle opening vtvtopto_base at the time of basic PTO operation is also increased in a step shape and then maintained at the predetermined value, and the throttle valve 3 is opened.

  With this control, the engine speed vnn gradually increases, but when the engine speed vnn increases beyond the target engine speed, the basic PTO operation throttle opening vtvopto_base gradually decreases and the throttle valve 3 gradually closes.

  This control has a problem in that an undershoot occurs in which the engine rotational speed vnn is changed from rising to falling and greatly falls.

  As a countermeasure against this, as shown in FIG. 4 (b), if the throttle opening vtvtopto_base at the time of basic PTO operation is slowly changed by the integral attenuation process, the control response of the engine speed decreases, and the engine speed at the time of load change. There was a problem that the change of the becomes large.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an engine output control device that can effectively suppress undershoot, hunting, and the like of engine rotation speed.

In the present invention, a throttle valve that adjusts the intake air amount and an actuator that opens and closes the throttle valve are provided, and the throttle opening of the throttle valve is set in accordance with the detected work accelerator opening vapstopper and the engine speed vnn. A basic throttle opening calculation means for calculating a basic throttle opening vtvtopto_base according to a working accelerator opening vapstopper and an engine rotational speed vnn for adjusting engine output in an engine output control device to be controlled, and an accelerator operation amount and the lower limit processing determination opening degree calculation means for calculating a lower limit processing threshold opening vtvoptomin_judg depending on the working accelerator opening vapsptoper is, multiplied by the one or more coefficients to the lower limit value processing threshold opening vtvoptomin_judg Determining a lower limit throttle opening degree calculation means when PTO is in operation, the time limit value processing calculated basic PTO operation when the throttle opening degree vtvopto_base falls below the lower limit processing threshold opening vtvoptomin_judg for calculating a lower limit throttle opening vtvoptomin during PTO operation Te And lower limit value processing means for switching the throttle opening vtvtopo during PTO operation from the basic PTO operation throttle opening vtvtopto_base to the PTO operation lower throttle opening vtvtopom during the lower limit processing.

  According to the present invention, when the work accelerator opening vastoptoper is maintained at a predetermined value after increasing in a stepwise manner, the basic PTO operating throttle opening vtvtopo_base is also based on the calculated basic PTO operating throttle opening vtvopto_base. After increasing in steps, it is kept at a predetermined value and the throttle valve is opened.

  With this control, the engine speed vnn gradually increases, but when the engine speed vnn increases beyond the target engine speed, the throttle opening vtvtopto_base during basic PTO operation gradually decreases and the throttle valve gradually closes. By this control, the engine speed vnn is changed from increasing to decreasing.

  When the lower limit value processing time when the throttle opening vtvtopto_base during the basic PTO operation falls below the lower limit processing determination opening vtvoptomin_judg is determined, the throttle opening vtvtopo during the PTO operation is changed from the throttle opening vtvtopto_base during the PTO operation to the lower limit throttle opening during the PTO operation. Switch to vtvoptomin.

  By performing this lower limit processing, even if the engine speed vnn changes from increasing to decreasing, undershoot in which the engine speed vnn greatly decreases can be suppressed. As a result, the control responsiveness of the engine rotational speed vnn can be improved, and hunting of the engine rotational speed vnn with respect to engine load fluctuation can be suppressed.

  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 so as to coincide with 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 and performs feedback control so that the engine rotation speed approaches the target idle rotation speed.

  The rotation of the engine 1 is transmitted to the wheels via a transmission, a propeller shaft, a differential gear, a drive shaft and the like (not shown), and is transmitted from the transmission to an auxiliary device mounted on, for example, a cleaning vehicle via the PTO shaft.

  In order to adjust the output of the engine 1, an accelerator pedal and a work accelerator lever (not shown) are provided. The accelerator opening amount vapstopper, which is the accelerator operation amount of the accelerator pedal and the operation accelerator lever, is detected by an accelerator opening sensor (not shown).

  A PTO switch for commanding the control unit 10 to operate the auxiliary device is provided. When the PTO switch is turned on, the auxiliary device is activated, and when the PTO switch is turned off, the operation of the auxiliary device is stopped.

  In the present embodiment, when the PTO switch is turned on, the accelerator operation amount of the work accelerator lever is set to a predetermined value.

  The control unit 10 includes an engine speed signal output from the crank angle sensor 11, a work accelerator opening signal of the work accelerator lever output from the work accelerator opening sensor, a signal output from the PTO switch, and the like. The drive signal is output to the actuator 4 that opens and closes the throttle valve 3.

The control unit 10 includes a basic throttle opening degree calculation means 13 for calculating a basic throttle opening degree vtvtopto_base (A) based on a map M1 set in advance according to the working accelerator opening degree vapstopper and the engine speed vnn, Lower limit value processing determination opening degree calculation means 15 for calculating lower limit value processing determination opening degree vtvoptomin_judg (B) based on a map set in advance according to opening degree vapstopper, and a coefficient of one or more for lower limit value processing determination opening degree vtvoptomin_judg over the PTO operation at lower throttle opening degree calculation means 14 for calculating a lower limit throttle opening vtvoptomin during PTO operation, the basic PTO operation when the throttle opening degree vtvopto_base (a) is a lower limit processing threshold opening vtvoptom Lower limit value processing determining means 16 for determining the lower limit value processing time that falls below n_judg (B) and the PTO switch is turned ON, and the throttle opening vtvtopo at the time of PTO operation at the lower limit value processing is set to the throttle opening vtvtopto_base (at the time of basic PTO operation) A lower limit processing means 19 for switching from A) to the lower limit throttle opening vtvoptomin during PTO operation.

  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, it is determined in step 1 that the PTO switch is ON, a detection value vnn of the engine speed is read in step 2, and a detection value of the work accelerator opening vapstopper is read in step 3.

  Subsequently, the routine proceeds to step 4 where a basic PTO operating throttle opening vtvtopto_base (A) is calculated based on a map M1 preset in accordance with the work accelerator opening vapstopper and the engine speed vnn. The processing performed in Step 4 corresponds to the throttle opening degree calculation means 13 at the time of basic PTO operation.

  Then, the process proceeds to step 5 to calculate a lower limit processing determination opening degree vtvtoptomin_judg (B) based on a map M2 set in advance according to the work accelerator opening degree vapstopper. The processing performed in step 5 corresponds to the lower limit throttle opening calculation means 14 during PTO operation.

  In the map M2, the set lower limit value processing determination opening vtvtoptomin_judg (B) gradually increases from 0 to 34% as the work accelerator opening vapstopper increases from 0 to 100%. Is arbitrarily set for each work accelerator opening vapstopper based on experiments.

  Subsequently, the routine proceeds to step 6 where it is determined whether or not the throttle opening vtvtopto_base (A) at the time of basic PTO operation is the lower limit processing at which the lower limit processing determination opening vtvoptomin_judg (B) is equal to or less. The processing performed in step 6 corresponds to the lower limit processing determination means 16.

  If it is determined in step 6 that the lower limit value is not being processed, the process proceeds to step 7 where the PTO operation lower limit throttle opening vtvvotomin is not calculated.

On the other hand, when it is determined in step 6 that the lower limit value is being processed, the process proceeds to step 8 where the lower limit value process determination opening vtvtopmin_judg is multiplied by a factor of 1 or more to calculate the PTO operating lower limit throttle opening vtvoptomin. . The processing performed in step 8 corresponds to the lower limit throttle opening calculation means 14 during PTO operation.

In the present embodiment, the lower limit throttle opening vtvoptomin at the time of PTO operation is calculated by the following expression that multiplies the lower limit processing determination opening vtvoptomin_judg (B) by a coefficient K of 1 or more.
vtvoptomin = vtvoptomin_judg × K (1)
Subsequently, the routine proceeds to step 9, where the PTO operation throttle opening vtvtopo is switched from the basic PTO operation throttle opening vtvtopto_base (A) to the PTO operation lower limit throttle opening vtvtopmin and held for the holding time vtptomin.

  This holding time vtptomin is calculated according to the lower limit processing determination opening degree vtvtopmin_judg (B). The holding time vtptomin is set based on experiments so that the holding time vtptomin becomes longer as the lower limit processing determination opening degree vtvtoptomin_judg (B) becomes larger.

  Subsequently, the routine proceeds to step 10, where the throttle opening vtvtopo at the time of PTO operation is gradually decreased from the lower limit throttle opening vtvoptomin at the time of PTO operation according to the attenuation amount vdiptomin [% / 10 ms].

  This attenuation amount vdiptomin is calculated according to the lower limit processing determination opening degree vtvoptomin_judg (B). The holding time vtptomin is set based on experiments so that the holding time vtptomin becomes larger as the lower limit processing determination opening degree vtvtoptomin_judg (B) becomes larger.

  Then, the process proceeds to step 11 to determine the lower limit throttle opening C (vtvoptomin) during PTO operation.

  Subsequently, the routine proceeds to step 12, where it is determined whether or not the basic PTO operation throttle opening vtvtopto_base (A) is equal to or less than the PTO operation lower limit throttle opening C (vtvoptomin).

  If it is determined in step 12 that A> C, the process proceeds to step 13 to select a basic PTO-operating throttle opening vtvopto_base (A), while if it is determined in step 12 that A ≦ C, step 14 is selected. Then, the lower limit throttle opening C (vtvoptomin) at the time of PTO operation is selected, and A or C selected at the subsequent step 15 is output as the throttle opening at the time of PTO operation.

  The processing performed in the above steps 8 to 15 corresponds to the lower limit processing means 19.

  FIG. 3 is a timing chart showing an example of a control operation executed by the control unit 10. This shows a situation in which the main control is performed when the auxiliary device starts operating when the PTO switch is turned on, thereby preventing an undershoot that once falls after the engine speed vnn increases.

  Explaining this, if the PTO switch is turned on during operation of the auxiliary device, the working accelerator opening vapstopper is increased in a stepwise manner and then maintained at a predetermined value, and the calculated basic PTO operating throttle opening vtvtopto_base (A) On the basis of the above, the throttle opening vtvtopto at the time of PTO operation is similarly increased in a step shape, and then maintained at a predetermined value, and the throttle valve 3 is opened.

  With this control, the engine speed vnn gradually increases, but when the engine speed vnn increases beyond the target engine speed, the throttle opening vtvtopto_base (A) during basic PTO operation and the throttle opening vtvtopo during PTO operation gradually decrease. Thus, the throttle valve 3 is gradually closed.

  This control causes the engine speed vnn to change from increasing to decreasing, and in the case of the conventional apparatus, there is a problem that an undershoot that greatly decreases as shown by a broken line occurs.

  In response to this, the present invention determines the lower limit value processing time when the basic PTO operation throttle opening vtvopto_base (A) falls below the lower limit value processing determination opening vtvtoptomin_judg (B), and this lower limit value processing time is determined. Then, control is performed to switch the throttle opening vtvopto at the time of PTO operation from the throttle opening vtvtopto_base (A) at the time of basic PTO operation to the lower limit throttle opening vtvoptomin at the time of PTO operation.

Also the engine rotational speed vnn by performing this lower limit processing is turned from rising to falling, falling write only the engine rotational speed vnn is suppressed as shown by the solid line, the operation of the auxiliary device is stabilized.

Since the lower limit throttle opening vtvoptomin at the time of PTO operation is calculated by multiplying the lower limit value processing determination opening vtvoptomin_judg (B) by a coefficient K of 1 or more, the throttle opening vtvopto at the time of PTO operation changes from a decrease to an increase depending on the operating conditions. To switch to the lower limit throttle opening vtvoptomin during PTO operation. Thereby, hunting of the engine speed vnn can be effectively suppressed, and the operation of the auxiliary device is stabilized.

In this lower limit processing control, the throttle opening vtvtopo at the time of PTO operation is switched from the throttle opening vtvtopto_base (A) at the time of basic PTO operation to the lower limit throttle opening vtvtopmin at the time of PTO operation, and held for the holding time vtptomin. vtptomin by becoming longer as the lower limit processing threshold opening vtvoptomin_judg (B) is increased, drop write only the engine rotational speed vnn are effectively suppressed.

  The throttle opening vtvopto at the time of PTO operation is gradually decreased from the lower limit throttle opening vtvoptomin at the time of PTO operation in accordance with the attenuation amount vdiptomin [% / 10 ms], and this attenuation amount vdiptomin becomes larger the lower limit processing determination opening degree vtvoptomin_judg (B). Therefore, the fluctuation of the engine rotational speed vnn can be effectively suppressed, and the engine rotational speed vnn can be quickly brought close to the target value.

  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 or other machine having a PTO shaft that can transmit the rotation of the engine to an auxiliary device, such as a crane truck or a cleaning truck.

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. The timing chart which similarly shows control operation. 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 13 Basic throttle opening calculation means at the time of PTO operation 14 Lower limit throttle opening calculation means at the time of PTO operation 15 Lower limit value processing determination opening degree calculation means 16 Lower limit value processing determination means 19 Lower limit Value processing means

Claims (3)

A throttle valve for adjusting the amount of intake air;
An actuator for opening and closing the throttle valve,
In an engine output control device that controls the throttle opening of a throttle valve according to a detected accelerator opening vapstopper for work and an engine speed vnn,
Basic throttle opening degree calculation means for calculating a basic throttle opening degree vtvtopto_base according to a working accelerator opening degree vapstopper for adjusting the output of the engine and the engine speed vnn;
A lower limit processing determination opening calculating means for calculating a lower limit processing determination opening vtvtoptomin_judg according to a work accelerator opening vapstopper which is an accelerator operation amount ;
A PTO operating lower limit throttle opening calculating means for calculating a lower limit throttle processing opening vtvoptomin by multiplying the lower limit processing determination opening vtvoptomin_judg by a coefficient of 1 or more;
A lower limit value processing determination means for determining a lower limit value processing time when the calculated throttle opening vtvtopto_base at the time of basic PTO operation falls below a lower limit value processing determination opening vtvtoptomin_judg;
An engine output control device comprising: a lower limit value processing means for switching the throttle opening vtvtopo at the time of PTO operation from the basic throttle opening vtvtopo_base at the time of PTO operation to the lower limit throttle opening vtvoptomin at the time of PTO operation at the time of the lower limit processing . The lower limit processing means switches the throttle opening vtvtopo at the time of PTO operation from the throttle opening vtvtopto_base at the time of basic PTO operation to the lower limit throttle opening vtvtopmin at the time of PTO operation and holds it for a holding time vtptomin.
2. The engine output control apparatus according to claim 1, wherein the holding time vtptomin is set to become longer as the lower limit value processing determination opening degree vtvtopmin_judg becomes larger. The lower limit processing means gradually decreases the throttle opening vtvtopo at the time of PTO operation from the lower limit throttle opening vtvoptomin at the time of PTO operation according to the attenuation amount vdiptomin,
The engine output control apparatus according to claim 1 or 2, wherein the attenuation amount vdiptomin is set to increase as the lower limit value processing determination opening degree vtvoptomin_judg increases.