JPH0213136B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel injection system for an internal combustion engine in which fuel adjustment of a fuel injection pump for a diesel engine of an automobile is performed using an actuator such as an electromagnetic actuator or an electro-hydraulic actuator. Regarding a control device.

[Conventional technology]

Conventionally, the governor for fuel adjustment in this type of fuel injection pump has an all-speed-regulating (all-speed) characteristic that performs a regulating action in all rotational ranges from idling rotational speed at low engine speeds to maximum rotational speed. Alternatively, high-speed control is performed to prevent the engine from exceeding its maximum rotational speed, low-speed control is performed to ensure smooth idling at low speeds, and no regulating action is performed at intermediate speeds. Rotation speed area (M-
M) Mechanical governors that utilize the centrifugal force generated by the rotation of flight weights have been used.

The former type of mechanical governor with all-speed characteristics can maintain a constant rotation speed even when the engine load fluctuates at any rotation speed, so it can be used at a constant rotation speed, such as in generator engines and construction machinery engines. Suitable for work engines that need to be operated. However, for the engine installed in a car etc. to drive the vehicle, road conditions,
The driving vehicle must quickly control the vehicle speed to a desired speed by pressing the accelerator pedal in a timely manner according to the load, etc., and when using a governor with this all-speed characteristic, the pressing force of the accelerator pedal can be controlled sensitively. I can't convey that feeling. Another drawback is that the accelerator pedal tends to be heavy, making acceleration feel inferior. For this reason, mechanical governors with the latter M-M characteristic are used for automobiles, which can quickly control the vehicle speed by controlling the degree of depression of the accelerator pedal in accordance with road conditions and load.

By the way, due to the recent development of automobile-only expressways, there is a method of driving that provides a comfortable ride by keeping the engine speed as constant as possible even when the ground is uneven, and minimizing changes in vehicle speed. It became necessary to realize this.

[Problem to be solved by the invention]

However, when attempting to achieve such constant speed driving, a vehicle governor with only a highly responsive M-M characteristic is unable to maintain constant speed driving when load fluctuation factors such as ground undulations are added during driving. In order to maintain this, the driver must press the accelerator pedal in very small amounts and in a complicated manner, which increases the driver's fatigue and is not good for traffic safety.

Therefore, an object of the present invention is to provide a fuel injection control device that can easily operate a vehicle smoothly.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention controls the fuel injection amount of an internal combustion engine installed in a car and used for driving the car based on a fuel injection pattern with a predetermined speed regulating characteristic. In the injection control device, a first control means for controlling a fuel injection amount based on a fuel injection pattern having a regulating characteristic in the entire rotation speed range; The second one controls the fuel injection amount.
a control means, a rotation speed detection means for detecting the rotation speed of the engine, a determining means for determining whether the variation amount of the engine rotation speed is large or small with respect to a predetermined value based on a signal from the rotation speed detection means; a selection means for automatically selecting either the first control means or the second control means in response to a determination result of the means; and a selection means for automatically selecting either the first control means or the second control means based on the regulating characteristic of the control means selected by the selection means. The fuel injection control device for an internal combustion engine includes an actuator for metering fuel.

[Effect]

According to the above configuration, when the vehicle is running, both the fuel injection pattern with the high rotation speed and low rotation speed region regulating characteristics and the fuel injection pattern with the entire rotation speed range regulating characteristic are used, and the vehicle In addition to making it possible to run the engine smoothly, the switching of each fuel injection pattern is automatically executed based on the amount of fluctuation in engine speed, further reducing the burden on the driver. can be done.

〔Example〕

Examples of the present invention will be described below. FIG. 1 shows a first embodiment of the present invention, and its configuration and operation will be explained.

In this embodiment, the operating condition detector 1 that detects the operating conditions of the engine 7, which is a diesel engine, as an electric signal is an accelerator operation amount detector 1a (FIGS. 3 and 8).
), rotation speed detector 1b (Fig. 2, Fig. 3, Fig. 8)
Figure). The M-M characteristic pattern generation circuit 2 (second control means) for normal running and the all-speed characteristic pattern generation circuit 3 (first control means) for constant speed running are electrical control circuits. It has a characteristic that an output V _P corresponding to a target fuel injection amount to be injected into the engine 7 can be obtained by inputting an accelerator operation amount signal and a rotation speed signal from the operating condition detector 1. The circuit diagrams of the M-M characteristic pattern generation circuit 2 and the all-speed characteristic pattern generation circuit 3 are shown in FIG. 3 and FIG. 8, respectively. Switch 4 is a selection switch (selection means)
The output of the M-M characteristic generating circuit 2 or the output of the all-speed characteristic generating circuit 3 can be selected according to the driver's will. The electromagnetic or electro-hydraulic actuator 5 drives the adjusting member of the fuel injection pump 6 to adjust the amount of fuel corresponding to the target injection amount characteristic V _P selected by the switch 4 and supply it to the engine 7 .

Figure 2 is an example of a constant speed driving detection circuit that can automatically switch from the M-M characteristic generating circuit 2 to the all-speed characteristic generating circuit 3 without the driver operating a switch when driving at a constant speed. I will explain it together. The rotation speed signal generation circuit 201 is the rotation speed detector 1
A circuit that generates a rotational speed signal V N by an electric signal representing the engine rotational speed N detected at b, that is, a pulse voltage signal with a frequency proportional to the rotational speed _N ,
The operational amplifier 212 outputs a rotational speed signal V _N that is approximately linearly proportional to the rotational speed N. The transistor 211 shapes the waveform of the pulse voltage signal from the rotation speed detector 1b. The differentiating circuit 202 is a circuit that outputs only the rotational speed variation _VL of the rotational speed signal _VN . The full-wave rectifier circuit 203 is an operational amplifier 23
1,232, this circuit performs full-wave rectification of the rotational speed variation V _L . The comparison circuit 204 is a circuit (discrimination means) that compares the output of the full-wave rectification circuit 203 by the operational amplifier 241 and the constant rotation setting value V _S , and if the rotation speed variation V _L is within the set rotation speed variation. For example, the comparator circuit output is almost the ground voltage (zero), and if it is outside the set rotation speed fluctuation, it is almost the power supply (200).
voltage.

The selection circuit 205 is a two-contact analog switch 2.
51 (selection means) is a selection circuit between the all-speed characteristic generation circuit 3 and the M-M characteristic generation circuit 2. If the output of the comparison circuit 204 is zero, that is, within the set rotation speed fluctuation, the analog switch 251 is turned off. The output of all speed characteristic circuit 3 is
Further, if the output of the comparison circuit 204 is the power supply (200) voltage, the analog switch 251 is turned on.
Select the output of the M-M characteristic generating circuit 2.

As detailed above, in the first embodiment, the engine 7
When the rotational speed variation due to the load is small, the constant speed operation detection circuit 8 detects the constant speed operation state intentionally performed by the driver and generates an all speed characteristic as the target injection amount V _P which is the output from the selection circuit 205. Select circuit 3.

FIG. 3 shows one embodiment of the MM characteristic circuit 2, and the configuration and operation will be explained below based on the MM characteristic (pattern) of FIG. 6. The rotational speed signal generation circuit 301 is configured to detect rotational speed of the rotational speed detector 1b among the operating conditions of the engine.
This is a circuit that generates a rotational speed signal V N by an electric signal representing the engine rotational speed N detected by the engine, that is, a pulse voltage signal with a frequency proportional to the rotational speed _N.
Rotational speed signal V _N output from operational amplifier 312
The relationship between the rotational speed N and the rotational speed N is almost linear as shown in FIG. Transistor 311 is rotation speed detector 1
This is to waveform shape the pulse voltage signal from b. In Fig. 4, the rotational speed signals corresponding to the rotational speed N ₀ , N ₁ , N ₂ , N ₃ , N ₄ are V _N0 , V _N1 , V _N2 ,
V _N3 and V _N4 .

The accelerator operation amount detection circuit 302 is a circuit that detects electric signals (voltage signals) V _A and V B representing the accelerator operation amount A or _B detected by the accelerator operation amount detector 1a among the operating conditions of the engine, Potentiometers 321, 322 that slide or rotate via links connected to the accelerator pedal
is output by The accelerator operation amounts A and B and the accelerator operation amount signal V _A or V _B are shown in Fig. 5, respectively.
As shown in Fig. 7, the accelerator operation amount A ₀ , A ₁ ,
The accelerator operation amount signals corresponding to A ₂ , B ₀ , B ₁ , and B ₂ are V _A0 , V _A1 , V _A2 , V _B0 , V _B1 , and V _B2 , respectively. The comparison circuit 303 is a circuit for comparing the rotation speed signal V _N from the operational amplifier 331 and the voltage value V _N1 corresponding to the rotation speed N ₁ from the potentiometer 333, and when V _N <V _N1 , the analog switch 332 on, when V _N ≧ V _N1 , analog switch 332
is turned off, and when V _N <V _N1 , the accelerator operation amount signal V _A is output from the accelerator operation amount detection circuit 302.
A target injection amount signal V P corresponding to the target injection amount signal V _P is output. The target injection amount signals corresponding to the accelerator operation amount signals V _A0 , V _A1 , and V _A2 are V _PA0 , V _PA1 , and V _PA2 .

The differential amplifier circuit 304 includes operational amplifiers 341 and 34.
2, and the differential amplification gains are G ₁ (G ₁ = V _PA − V _PB )/(V _N2 − V _N1 )), 1,
When the outputs are V _D1 and V _D2 , the rotation speed signal V _N and the voltage value V _N1 from the potentiometer 333 cause V _D1
= G ₁ (V _N −V _N1 ), and the accelerator operation amount signal V _A
Therefore, V _D2 = V _A − V _D1 = V _A − G ₁ (V _N − V _N1 ). The comparison circuit 305 is a comparison circuit between the rotational speed signal V _N from the operational amplifier 352 and the voltage value V _N2 corresponding to the rotational speed N ₂ from the potentiometer 351, and when V _N > V _N2 , the output of the operational amplifier 352 is approximately the power supply (200) voltage, and when V _N ≦V _N2, the output of the operational amplifier 352 is approximately the ground potential (zero).

The selection circuit 306 uses the NOR gate 361 and the analog switch 362 to set the rotation speed signal V _N to V _N1 ≦
This is a circuit that selects the output V _D2 of the differential amplifier circuit 304 as the target injection amount signal V _P when V _{N ≦V N2, and only when V N ≧ V N1} from the operational amplifier 331.
The input of the NOR gate 361 is ground potential (zero), and the NOR gate 3 is activated only when V _N ≦V _N2 from the comparator circuit 305.
The input of 61 becomes the ground potential (zero), and the analog switch 362 turns on when V _N1 ≦V _N ≦ V _N2 and outputs the target injection amount signal _VP to the differential amplifier circuit 304.
Select the output V _D2 of.

The comparison circuit 307 compares the rotational speed V _N by the operational amplifier 372 and the rotational speed N ₃ by the potentiometer 371.
This is a comparison circuit with the voltage value V _N3 corresponding to V _N <
When V _N3 , the output of the operational amplifier 372 becomes almost the power supply (200) voltage, and when V _N ≧ V _N3 , the output of the operational amplifier 372
The output of 72 is approximately at ground potential (zero).

The selection circuit 308 uses an AND gate 381 and an analog switch 382 to determine whether the rotation speed signal V _N is V _N2 <
When V _N < V _N3 , the accelerator operation amount signal by the potentiometer 322 is used as the target injection amount signal V _P
This is a selection circuit that outputs V _B , and the comparison circuit 305
Therefore, when V _N > V _N2 , the input of the AND gate 381 becomes the power supply voltage (200), and from the comparator circuit 307, when V _N < V _N3 , the input of the AND gate 381 becomes the power supply voltage, and the analog switch 382 becomes
It is turned on when V _N2 <V _N <V _N3 , and outputs a value corresponding to the accelerator operation amount signal V _B , which is the output of the accelerator operation amount detection circuit 302, as the target injection amount signal V _P. Accelerator operation amount signal V _B0 , V _B1 , V _B2
The target injection amount signals corresponding to are V _PB0 , V _PB1 , and V _PB2 .

The differential amplifier circuit 309 includes operational amplifiers 391 and 39
2, the gain is G ₂ (G ₂ = V _PB2 / (V _N4
-V _N3 )), 1, and if _the outputs are V _S1 and V _S2 , respectively, then V _S1 = V _S1 =
G ₂ (V _N −V _N3 ), and V _S2 = V _B − V _S1 = V _B − G ₂ (V _N − V _N3 ) due to the accelerator operation amount signal V _B.

The selection circuit 310 includes an analog switch 313,
This is a selection circuit using a not gate 314, and when V _N ≧ V _N3 from a comparator circuit 307, the not gate input becomes the ground potential (zero), and the analog switch 3
13 is turned on, and V _S2 is set as the target injection amount signal V _P.
Select and output.

With the configuration and operation detailed above, M-M in FIG.
The circuit of FIG. 3 outputs a characteristic (pattern).

FIG. 8 shows an embodiment of the all-speed characteristic circuit 3, and its configuration and operation will be explained. The accelerator operation amount detector 1a slides or rotates potentiometers 817 and 818 via a link connected to the accelerator pedal, and the relationship between the accelerator operation amount C and the resistance value R of the potentiometer 817 is expressed as follows. The relationship is as shown in Figure 9, and due to C ₂ = 2C ₁ and C ₃ = 3C ₁ , R ₂ = 2R ₁ and R ₃ = 3R ₁ . The relationship between the accelerator operation amount C and the accelerator operation amount signal V _C from the potentiometer 818 and the resistor 819 is V _C = UC ² (U is a constant) as shown in Fig. 11, and the accelerator operation amount
The accelerator operation amount signals corresponding to C ₁ , C ₂ , and C ₃ are V _CS1 , V _CS2 , and V _CS3 , respectively.

The rotation speed signal generation circuit 807 generates a rotation speed signal using an electric signal representing the engine rotation speed S detected by the rotation detector 1b among the engine operating conditions, that is, a pulse voltage signal with a frequency proportional to the rotation speed 7.
This circuit generates V _S , and the relationship between the rotation speed signal V _S output from the operational amplifier 816 and the rotation speed S is almost linear as shown in FIG. 10, and is proportional to the resistance R of the potentiometer 817. Because of the amplification relationship, the accelerator operation amount C=C ₁ , C=C ₂ , C
When = C ₃ , the relationships shown in Fig. 10 are obtained.
The rotation speed signal for the rotation speed S ₁ at the accelerator operation amount C=C ₁ is V _S1 , the rotation speed signal for the rotation speed S ₂ at the accelerator operation amount C=C ₂ is V _S2 , the rotation at the accelerator operation amount C=C ₃ The rotational speed signal for the number S ₃ is V _S3 .

The differential amplification circuit 804 is a differential amplification circuit using an operational amplifier 841, and a rotation speed signal generation circuit 807.
When inputting the output V _S and the accelerator operation amount V _C , the first
Obtain the all-speed characteristics shown in Figure 2.

In the above embodiment, the M-M characteristic generating circuit 2
Although the all-speed characteristic generating circuit 3 is constructed from an analog circuit, it is also possible to easily perform similar control using a microcomputer as a modification of the present invention.

〔Effect of the invention〕

As described above, according to the present invention, not only a fuel injection pattern with regulating characteristics in a high rotation speed and constant rotation speed range, but also a fuel injection pattern with regulating characteristics in the entire rotation speed range can be used as a pattern used for driving a car. For example, when controlling a car to run at a constant speed, the car can be driven by shifting to a fuel injection pattern with regulating characteristics over the entire rotation speed range, thereby reducing the driver's complicated accelerator operations. This can be made unnecessary and provides a comfortable driving experience. Furthermore, since the amount of variation in engine speed is detected and the fuel injection pattern is automatically switched based on the magnitude of this detected value, there is an excellent effect of further reducing the burden on the driver.

[Brief explanation of drawings]

1 and 2 are configuration diagrams of a fuel injection control device for an internal combustion engine as a first embodiment of the present invention, and FIG. 3 is a diagram of the M-M characteristic pattern generation circuit 2 in FIGS. 1 and 2. Electrical circuit diagram, Fig. 4 is a characteristic diagram of rotation speed vs. rotation speed signal for explaining the operation of the M-M characteristic pattern generation circuit, and Fig. 5 is a characteristic diagram for explaining the operation of the M-M characteristic pattern generation circuit. Characteristic diagram of accelerator operation amount vs. accelerator operation amount signal, Figure 6 is M
-A characteristic diagram of the rotation speed versus target injection amount signal for explaining the operation of the M characteristic pattern generation circuit, FIG.
- A characteristic diagram of accelerator operation amount versus accelerator operation amount signal for explaining the operation of the M characteristic pattern generation circuit, FIG. 8 is an electric circuit diagram of the all-speed characteristic pattern generation circuit 3 in FIGS. 1 and 2,
Fig. 9 is a characteristic diagram of accelerator operation amount versus potentiometer resistance value to explain the operation of the all-speed characteristic pattern generation circuit, and Fig. 10 is a characteristic diagram of the rotation speed to explain the operation of the all-speed characteristic pattern generation circuit. Figure 11 is a characteristic diagram of the accelerator operation amount versus rotational speed signal to explain the operation of the all-speed characteristic pattern generation circuit. Figure 12 is a characteristic diagram of the rotational speed signal versus the all-speed characteristic pattern generation circuit. FIG. 3 is a characteristic diagram of the rotational speed versus target injection amount signal for the purpose of the invention. 1...Operating condition detector, 1a...Accelerator operation amount detector, 1b...Rotation speed detector, 2...M-M
Characteristic pattern generation circuit, 3... All-speed characteristic pattern generation circuit, 4... Switch, 5... Electromagnetic or electro-hydraulic actuator, 6...
Fuel injection pump, 7... Engine, 8... Constant speed operation detection circuit, 201... Rotation speed signal generation circuit, 202
... Differential circuit, 203 ... Full-wave rectifier circuit, 204
... Comparison circuit, 205 ... Selection circuit, 301 ...
Rotation speed signal generation circuit, 302...Accelerator operation amount detection circuit, 303...Comparison circuit, 304...Differential amplifier circuit, 305...Comparison circuit, 306...Selection circuit, 307...Comparison circuit, 308... Selection circuit, 309... Differential amplifier circuit, 310... Selection circuit.

Claims (1)

[Scope of Claims] 1. A fuel injection control device for an internal combustion engine that is mounted on a vehicle and used to drive the vehicle by controlling the fuel injection amount of the internal combustion engine based on a fuel injection pattern with predetermined speed regulating characteristics to drive the vehicle. , a first control means for controlling the fuel injection amount based on a fuel injection pattern having a regulating characteristic in the entire rotation speed range; and a first control means for controlling the fuel injection amount based on a fuel injection pattern having a regulating characteristic in a high rotation speed and a low rotation speed region second to control
a control means, a rotation speed detection means for detecting the rotation speed of the engine, a determination means for determining whether the variation amount of the engine rotation speed is large or small with respect to a predetermined value based on a signal from the rotation speed detection means; a selection means for automatically selecting either the first control means or the second control means in response to a determination result of the means; and a selection means for automatically selecting either the first control means or the second control means based on the regulating characteristic of the control means selected by the selection means. A fuel injection control device for an internal combustion engine, comprising an actuator for metering fuel.