JPS6312863A - Engine controller - Google Patents

Abstract

PURPOSE:To improve the starting and accelerating performance, by varying the low idle rotation of engine to second low idle rotation lower than a first low idle rotation when a transmission is shifted to neutral or reverse position. CONSTITUTION:Under such operating condition where an acceleration pedal 4 is not stepped while a shift lever 5 is set to N, R and a switch element 111 is closed, second low idle rotation (about 600rpm) lower than a first low idle rotation (about 1,000rpm) being set under other operating condition is commanded as a target rotation. A controller 11 compares the target rotation with an actual rotation fed from a rotation sensor 2, then the difference is applied with PID compensation thus producing a target injection quantity. Smaller one of the target injection quantity or an allowable maximum injection quantity corresponding to an engine rotation fed from a memory 6 is selected and utilized for positional control of a control rack 7 for a fuel injection pump 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine control device that changes the low idle rotation speed of the engine under specific shift conditions.

[Conventional technology]

Conventionally, one low idle speed is set for the engine.

[Problem that the invention seeks to solve]

From the standpoint of starting and acceleration, it is desirable that the engine's low idle speed be high. Because, in Figure 2, O→
This is because, as shown in the 10 m vehicle acceleration characteristic, the lower the low idle rotation speed, the longer the time required for acceleration.

On the other hand, as shown in Figure 3, the engine's fuel consumption when not driving increases as the low idle speed increases, so in order to reduce fuel consumption when not driving, it is necessary to lower the low idle speed as much as possible. desirable.

Furthermore, when going backwards, the accelerator is delicately operated and the brakes are frequently operated, so it is better to set the low idle rotation speed low in order to perform such operations smoothly.

However, conventionally, as mentioned above, only one low idle speed is set, so if this low idle speed is set high, it becomes impossible to reduce fuel consumption, and if it is set low, it is difficult to start or accelerate. This resulted in the inconvenience of poor performance.

[Means to try to solve problems]

In order to avoid such inconvenience, the present invention includes a shift position detection means for detecting that the shift position of the transmission is neutral and reverse, and when the shift position detection means detects neutral and reverse, An idle speed reducing means is provided for reducing the low idle speed of the engine from a first low idle speed to a second low idle speed lower than the first low idle speed.

[Effect]

According to the present invention, when the shift position of the transmission is neutral or reverse, the low idle rotation speed of the engine is changed from the first low idle rotation speed to the second low idle rotation speed.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of an engine control device according to the present invention, which is applied to an engine of a dump truck or the like.

In the figure, the accelerator sensor outputs a signal corresponding to the amount of depression (operation amount) of the accelerator pedal 4, that is, a signal indicating the target rotation speed Nr of the engine (not shown), and the engine rotation sensor 2 outputs a signal corresponding to the amount of depression (operation amount) of the accelerator pedal 4. Furthermore, the shift position detection sensor 3 outputs a signal indicating that the shift lever 5 is set to the neutral position N and the reverse position R, respectively. The shift lever 5 is used to set a shift position of a transmission (not shown).

Memory 6 contains the maximum allowable injection according to the engine speed N! 8 quantity, that is, the same injection quantity Q2 that limits the torque generated by the engine is stored.

The control rack 7 controls the injection amount of the fuel injection pump 8 by its positional displacement, and in this embodiment, a proportional solenoid 9 is used as an actuator for displacing the rack 7.

Note that the position of this rack 7 is detected by a position sensor 0.

A normally open switch element 111 provided in the controller 1 (consisting of a CPU, etc.) is closed when the shift position sensor 3 detects neutral N or reverse R. The switch element 111 receives a target engine rotation speed N commanded by the accelerator sensor. A signal that lowers the rotation speed (for example, 400 rpm) is sent to the setting device 11.
Two items have been added.

Now, assuming that the accelerator pedal 4 is not depressed, in this state, the accelerator sensor sends a signal that commands the first low idle speed (for example, 1000 "pl"), that is, commands the target engine speed N (L,). At this time, the shift lever 5 is set to N, RJ, 4.
Outer place flf (Fl.

F2. F3) and the switch 111 is in the open state, the controller 11 calculates the output difference between the sensor and the sensor 2, that is, the target engine rotation speed N.
(11) and the actual engine speed N, the deviation ΔN=N(Ll)−N8 is calculated (step 113), and a process of applying well-known PID compensation to this deviation ΔN is executed ( Step 114
).

As a result, the signal indicating the deviation ΔN is multiplied by 0, and this multiplied signal is the target fuel injection ff1 for eliminating the deviation ΔN.
This indicates Q1.

Next, the controller executes a process of reading out the allowable maximum injection amount Q2 corresponding to the engine speed N from the memory 6 based on the output of the engine speed sensor 2. Then, a signal indicating the above-mentioned maximum allowable injection ff1Q2 and the above-mentioned injection f
The smaller signal among the signals indicating f1Q1 is selected (step 115), and this selected signal is converted into a rack position command signal (step 116).

The controller 1 then determines the deviation between the rack position command signal obtained in step 116 and the rack position signal output from the rack position sensor 0 (step 117). This deviation signal is sent to the D/A converter 12.
and is applied to the proportional solenoid 9 via the drive circuit 13, and as a result, the position of the control rack 7 is controlled so that the rack position deviation signal becomes zero.

In this way, the rotational speed ΔN becomes zero, that is, the engine rotational speed becomes the first low idle rotational speed N (Ll
) The injection lift of the injection pump 8 is controlled so that

When the accelerator pedal 4 is depressed, the fuel injection amount is similarly controlled so that the rotational speed deviation ΔN=N − N becomes zero, thereby increasing the engine rotational speed to the target rotational speed Nr. .

Note that if the target injection ff1Q1 corresponding to the deviation ΔN is larger than the limited injection ff1Q2 read out by the memory 6, the target injection amount Q is limited to Q2.
There is no risk that the engine will generate more torque than the allowable torque.

Next, the shift lever 5 is moved to the neutral position N or the reverse position R.
The following describes the case where it is set to .

In this case, since the switch element 111 is opened,
A process of subtracting the output of the setter 112 from the output of the accelerator sensor is executed (step 118), thereby converting the target rotational speed N to N - N.

0 Assuming that accelerator pedal 4 is not depressed now,
This changed target rotation speed is the second low idle rotation speed Nr(L)=N(Ll)N.

r becomes. Therefore, this O - idle speed N.

(L2) and the actual engine speed N. deviation ΔN=N
The fuel injection amount of pump "8" is controlled so that (L2)-Ne becomes zero, and thereby the engine is rotated at the second low idle rotation speed Nr (L2).

This example works in this way, so as mentioned above, N (Ll) is 1000 rpm and No is 400 rpm.
rpm, the low idle rotation speed when the shift lever 5 is set to a position other than N or R is 10
00rpl, and when the same lever is set to positions N and R, it becomes 600rl)In.

Therefore, the speed stages Fl and F2 for forward traveling are
．． When either F3 is selected, good starting acceleration is achieved based on the high low idle speed when driving forward, and low low idle speed when in neutral, i.e. when not driving, reduces fuel consumption and noise. can be achieved. Furthermore, when reversing, the low idle speed allows delicate accelerator operation, and the engine's braking performance is also improved in response to brake operation.

In the above embodiment, the first. I am trying to select the second low idle speed, but
Of course, it is also possible to provide the transmission with a sensor that detects the shift state and select each of the above low idle rotational speeds based on the output of this sensor.

Further, in the case of a vehicle equipped with an automatic transmission, the shift state is electrically known from the signal for selecting the transmission clutch, so the above-mentioned first. It is also possible to select a second low idle speed.

〔Effect of the invention〕

According to the present invention, when the shift position of the transmission is neutral or reverse, the low idle rotation speed of the engine is automatically set from the first low idle rotation speed to the second low idle rotation speed lower than this rotation speed. be done.

Therefore, it is possible to improve the starting acceleration when the vehicle is traveling forward, and to reduce fuel consumption and engine noise when the vehicle is not traveling. There are also advantages such as ease of delicate accelerator operations when moving backwards.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an engine control device according to the present invention, FIG. 2 is a graph illustrating the relationship between low idle speed and acceleration time, and FIG. 3 is a graph showing the relationship between low idle speed and acceleration time. It is a graph illustrating the relationship with fuel consumption amount. DESCRIPTION OF SYMBOLS 1... Accelerator sensor, 2... Engine rotation sensor, 3... Shift position sensor, 4... Accelerator pedal, 5... Shift lever 16... Memory, 7... Control rack, 8 ...Fuel injection pump, 9...
Proportional solenoid, 11... Controller, 111...
・Switch, 112...setting device. Idle rotation 1q (rl) m) Idle rotation speed (rpm)

Claims (1)

[Scope of Claims] Shift position detection means for detecting that the shift position of the transmission is neutral and that the shift position is reverse, and when the shift position detection means detects neutral and reverse, the low idle of the engine An engine control device comprising: an idle rotation speed reducing means for lowering the rotation speed from a first low idle rotation speed to a second low idle rotation speed lower than the first low idle rotation speed.