JPS5968540A - Controller for air-fuel mixture of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent engine stall from generating due to stabilizing combustion, by providing a device detecting that operation of a reduction speed of a vehicle has been made and a device opening and closing a bypass air duct bypassing a throttle valve. CONSTITUTION:A solenoid control valve 32 is provided in a bypass air duct 31 bypassing a throttle chamber 16. A control unit 11 controls opening and closing of a solenoid control valve 32 and controls fuel through an injector 10. When operation of a reduction speed of a vehicle has been made, air is supplied to a suction air duct 9 by opening the solenoid control valve 32. An air-fuel ratio, therefore, can be prevented from reducing suddently. Thereby engine stall is prevented from occurring, because torque can be prevented from deteriorating.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention appropriately controls the air-fuel ratio in an internal combustion engine during a vehicle deceleration operation in which the throttle valve is substantially fully closed.
The present invention relates to a mixture control device that stabilizes combustion and prevents occurrence of engine stall.

As a conventional air-fuel mixture control device for an internal combustion engine, for example, the first
A combination of the fuel system shown in Figure 2, the air system shown in Figure 2, and the electronic control system is known.

In the fuel system shown in Figure 1, the fuel is in the Tsuyuel tank 1.
The fuel is sucked in by the fuel pump 2, pressurized, and pumped out. Next, the fuel pulsation generated in the fuel pump 2 is damped by the fuel damper 3, and the fuel filter 4
After dust and moisture are removed by the pressure regulator 5, the fuel is regulated to a constant fuel pressure and is injected into the injector (fuel injection valve) attached to the intake manifold 9 near the intake valve 8 of each cylinder 7 of the engine 6. 1
From 0, fuel is injected at a predetermined time by a predetermined injection amount T (injection time) calculated by the control unit 111 as described later.

Incidentally, surplus fuel is returned to the tsuyuel tank 1 from the pressure regulator 5. 12 is a water temperature sensor that detects the temperature of the cooling water; 13 is a cold start valve that is opened to increase the amount of fuel supplied when starting the engine when the temperature of the cooling water is low.

The air system is as shown in Figure 2, air is supplied to air cleaner 1.
The intake air amount Q is measured by the air flow meter 5, the intake air amount Q is adjusted by the throttle valve 17 in the throttle chamber 16, and the air is injected from the above-mentioned injector IO in the intake manifold 9. The air-fuel mixture is supplied to each cylinder 7 after being mixed with the fuel. The throttle chamber 16 has an off (off) state when the throttle valve 17 is open.
Low) signal, no on (high) signal when closed, slot 7)
Rusuisoji 18 is attached. 19 is a bypass passage for intake air when the throttle valve 17 is closed (that is, idling); 20 is an idle adjustment screw that adjusts the air flow rate in the bypass passage 19;
Reference numeral 1 denotes an air regulator which serves as an auxiliary air valve to increase the amount of air during startup and subsequent warm-up operation.

Next, the electronic control system is controlled in the control unit II by using the intake air amount Q signal from the L aphrometer 15 and the crank angle sensor 4I2 mounted on the crankshaft of the engine 6.
Basic injection amount Tp 'rp=+: (Q/N) (K is a constant) -
(Calculate 11.Furthermore, various information detected about the state of the engine and each part of the vehicle is input, and the correction of the injection amount is calculated.
The actual fuel injection amount T is determined, and the injector 10 is driven simultaneously in each cylinder once per engine revolution using this T.

To explain the various corrections in detail, the )\noteli voltage correction Ts as a correction due to fluctuations in the drive voltage of the injector 10 is as follows:
As shown in FIG. 3, depending on the internal voltage VB, Ts = a + b (14VB) - (21 (where a and b are constants) is given.

The water temperature increase correction Ft when the engine is not sufficiently warmed up is:
It is determined from the characteristic diagram shown in FIG. 4 according to the water temperature.

In order to obtain smooth starting performance and to smoothly transition from starting to idling, the post-starting increase correction KAs is as follows:
The initial value KAso when the starter motor is turned on is
It is determined from the characteristic diagram shown in FIG. 5 according to the water temperature at that time, and thereafter decreases to 0 as time passes.

The post-idle increase correction KAi, which is used to smooth the start when warm-up has not been performed sufficiently, is performed by adjusting the throttle switch 1.
Initial value KAi when 8 is turned off.

is determined from the characteristic diagram shown in FIG. 6 according to the water temperature at that time, and thereafter decreases to 0 with the passage of time.

In addition, correction using an exhaust sensor may be performed.

Furthermore, the following control is performed when starting the engine.

T+-Tpx (1-1-KAs)Xl, 3→-Ts・
...(3) T2 = TSTxKNSTxKTST
-...(The two values of 41 are calculated, and the larger one is set as the fuel injection amount at the time of starting.

In formula (4), TST, KNST, and KTST are determined according to the water temperature, engine speed, and elapsed time after startup, respectively.
They are obtained from the characteristics shown in FIGS. 7, 8, and 9, respectively.

However, with such conventional internal combustion engine mixture control devices, when deceleration is performed, in other words, the rotation speed of a special engine with a clutch connected when the throttle valve is fully closed or almost fully idle suddenly increases. 1st
As shown in Figure 0, there is a delay in the amount of air entering the cylinder, and fuel is supplied in an amount corresponding to Tp = K (Q/N), so the amount of air taken into cylinder C4 is relatively As the air-fuel ratio decreases, the air-fuel ratio becomes a little less than δ, and the air-fuel mixture becomes rich. When the air-fuel ratio decreases in this way, the 1-lux decreases, and the 1~
The decrease in torque promotes a decrease in the air-fuel ratio and further decreases the torque, leading to a shift in direction (a), resulting in the problem that enrichment is more likely to occur.

The present invention has been made in view of these conventional problems, and has a structure in which bypass air is replenished to correct the air-fuel ratio by increasing the air-fuel ratio when the engine speed suddenly decreases due to deceleration operation of the vehicle. It is an object of the present invention to provide a mixture control device for an internal combustion engine, which prevents a decrease in torque and prevents operational malfunctions such as engine stall.

The present invention will be explained below based on illustrated embodiments.

However, in FIG. 11 showing the overall configuration of one embodiment, the same components as those in the conventional drawings are given the same reference numerals to simplify the explanation.

In FIG. 11, a bypass air passage 31 is provided which bypasses the throttle chamber 16 of the intake manifold 9 and connects its upstream and downstream parts, and an electromagnetic control valve 32 is interposed in the high-pass air passage 31. The bypass air passage has its upstream end connected to the air flow meter 1 as shown by the chain line in the figure.
It may be connected upstream from 5. On the other hand, when the throat I/le chamber 16 is fully closed, the throttle half 17 is
In addition to providing a throttle switch 1 day that is N, a rotation speed sensor 33 that generates a pulse signal on the crankshaft or the like every 1 degree rotation of the engine, and a reference signal generator 34 that generates a pulse signal every 1 rotation of the engine. will be established. Furthermore, there is a vehicle speed sensor 35 that generates a pulse signal according to the vehicle speed, a clutch switch 36 that is turned on when the clutch is engaged, and a neutral switch that is turned on when the gear is in the neutral or rearrange position. Border 3F, Reno＼
- Equipped with sui-nochi 38.

Then, the throttle switch 185 rotation speed sensor 3
3. Reference signal generator 34. Vehicle speed sensor 35. Clutch sui, 1,36. Connect the neutral switch 37 and reverse switch 38 to the input terminal of the control unit 11, and also connect the controller I-low) Ii unit 1
An electromagnetic control valve 32 is connected to the output terminal of the control unit 1, and based on the above-mentioned signals, the signals are supplied to the fd output electromagnetic control valve 32 controlled by the control unit 1-11 to control opening and closing. ing. Further, the injector 10 is connected to the incoming output terminal of the control unit 11, and the fuel is controlled based on the basic injection amount TI).

FIG. 12 shows an embodiment of a control circuit for driving an electromagnetic control valve. In the figure, 18. Reference signal generator 34. 36. The signals from the neutral switch 37 and the rehearsing switch 3B are directly input to the arithmetic circuit 39. The signals from the rotation speed sensor 33 and the vehicle speed sensor 35 are input to each pulse counter 40. The number of pulses of the signal generated from the vehicle speed sensor 35 during a certain period of time is counted to calculate the engine rotation speed N and the vehicle speed, respectively, and each signal is input to the calculation circuit 39 64
2 is a memory that stores the latest n signals of the engine rotation speed N inputted from the arithmetic circuit 39; The average value of N is calculated, and it is determined whether or not the latest engine speed rl is smaller than the difference between the average value N and the set value (ΔN). Then, the arithmetic circuit 39 calculates the operating information based on the signals from each sensor, switch, and memory and the condition 1.2 of 2M4 (described later) regarding the preset operating state, etc.
The calculations described later are performed in rotational synchronization or time synchronization. The transistor 43 is ON-OFF controlled in accordance with the signal output from the arithmetic circuit 39, and opens and closes the electromagnetic control valve 32 connected to the collector terminal of the transistor 43.

44 is a battery.

Note that the conditions 1 and 2 described above are set as follows, for example.

As condition 1, fal The vehicle speed is less than the set value.

tb+throttle opening is less than the set value.

(C) The gear position is neutral (drive, not reverse).

(d11 Engine rotation number N is below the set value.

Condition 2 is as follows: (81 The engine speed N is a predetermined rotation speed or is smaller than the difference N-ΔN between the average rotation speed N for a predetermined time and the set value ΔN.

(The bl clutch is in the connected state.

(The set time has elapsed since the Cl clutch was connected.

Next, a specific example of a control system for the electromagnetic control valve 32 in such an apparatus will be explained according to the flowcharts shown in FIGS. 13 to 16. In the case shown in FIG. 13, first, it is determined whether condition 1 is satisfied based on information regarding condition 1 among the signals from each sensor, switch, and memory (101), and it is satisfied (YES). ), then it is determined whether condition 2 is satisfied based on the information regarding condition 2 (102), and when this is also satisfied (YES), that is, when conditions 1 and 2 are both satisfied, Then, the output of the arithmetic circuit 39 turns on, turning on the transistor 43, opening the electromagnetic control valve 32, and opening the bypass air passage 31 (103).

As a result, when a deceleration operation is performed to reduce the engine speed N, such as when the clutch is connected with the throttle valve 17 fully closed, intake air is replenished via the bypass air passage 31. On the other hand, there is a delay in increasing the intake air amount Q detected by the air flow meter 15 on the upstream side of the throttle valve 17 due to the replenishment, and therefore, the fuel injection amount Tp=K (Q
/N), the amount increases quickly due to a decrease in engine speed, but there is a delay in increasing the amount due to intake air replenishment. Therefore, the delay in increasing the amount of air taken into the cylinder is balanced with the delay in increasing the amount of fuel injection, making it possible to prevent a sudden drop in the air-fuel ratio, that is, to prevent the air-fuel mixture from becoming too rich, and to prevent a decrease in Li-rek. As a result, engine stalls and other malfunctions of the engine can be effectively prevented.

Also, either condition 1 or 2 is no longer satisfied (No.
) In the IW, the output of the arithmetic circuit 35 is turned OFF, the transistor 43 is turned OFF, and the no-input air passage 3 is turned OFF.
1 is closed (104), and normal air-fuel ratio control is performed.

In addition, the engine speed N is transferred to the memory 424 for each calculation (
105) Finish each operation.

Next, what is shown in FIG. 14 will be explained.

First, determine whether conditions 1 and 2 are satisfied or not.
1L112), if both are satisfied (YES), flag 1 (Fl) = 1, hula knob 2 (F2) -
1 (113), and turns on the transistor 43 to open the bypass air passage 31 and replenish air (114).
).

When only condition 2 is no longer satisfied from this state (NO
), F1=1, F2=1 based on the previous calculation result.
115, 116), set F 2 = O and set the counter C1 (117)
.

At this time, the bypass air passage 31 is kept open. When this state continues, Cl=C1-1 is calculated to measure the duration (11B
) After a predetermined time or after a predetermined rotation (when the determination result (119) of C1 becomes CI≦0), set Fl-0 (120) and turn off the transistor 43 to close the bypass air passage 31 ( 1'21) Furthermore, if Condition 1 is no longer satisfied in a state in which both Conditions 1 and 2 are satisfied, the transistor 43 is immediately turned off to close the bypass air passage 31.

The period number of rotations N is transferred to the memory (122) as in the previous embodiment. That is, in this control method, when conditions 1 and 2 are both satisfied and air replenishment is being performed, condition 2 is satisfied.
When this is no longer satisfied, air is replenished for a predetermined period of time from this point on, and then the bypass air passage 31 is closed to return to normal air-fuel ratio control.

In the system shown in FIG. 15, when conditions 1.2 are both satisfied and the bypass air passage 31 is open, when only one of conditions 1.2 is no longer satisfied, a predetermined After a period of time, the bypass air passage 31 is closed.

That is, it is necessary to determine whether condition 1 is satisfied 131
), when it is satisfied, the counter I = 1 and 1
32), If not satisfied, set I=O (133
). Next, it is necessary to determine whether condition 2 is satisfied or not.13
4) If satisfied, calculate I-1+113
5), and then the result of this calculation is determined (136). The above calculation result is l-2 (conditions 1 and 2 are both satisfied)
If so, set F1=1 and F2=1 (137), turn on the transistor 43, and open the bypass air passage 31 (138). From this state, when only one of conditions 1 and 2 is no longer satisfied, 1=1. F1
= 1°F2-1 (139, 140, 141)
, F 2 = 0 and the counter C1 is set (142).

At this time, the bypass air passage 31 is kept open. If this state continues, calculate C1=C1-1 in the same way as the control method described above143)
, the value of CI is determined (144), and when C1≦0, it is set to Fl-0 (145), and the transistor 43 is turned off to close the bypass air passage 31 (144).
46). Further, when both conditions 1 and 2 are no longer satisfied (I=0), the transistor 43 is immediately turned off to close the bypass air passage 31. The engine speed N is transferred to the memory for each calculation (147).

Furthermore, in the three control methods described above, if the solenoid control valve 32 continues to open for a predetermined period of time or after a predetermined rotation after the bypass air passage 31 opens, the solenoid control valve 32 is immediately closed. At the same time, the electromagnetic control valve 32 remains unchanged until the operating conditions reach normal air-fuel ratio control that does not require replenishment of air from the bypass air passage 31.
may be held in a closed state, and the detection of the deceleration operation state may be started again from the time when the above-mentioned operating conditions are satisfied.

An example of such a control system is shown in FIG.

This example is applicable to the control method shown in FIG.

That is, it is necessary to determine whether condition 1 is satisfied 151
), if it is satisfied, then it is determined whether condition 2 is satisfied or not (152), ? If 8 has been added, the value of <Fl is determined based on the previous calculation result (153).

The value of Fl is based on the previous calculation result, and if either condition 1.2 was not satisfied and the bypass passage 31 was closed last time, F1 is set to 0 (15
4), it is determined that F1=O. As a result, the setting counter Ca1r is set to Fl-1 (155)
-F2=O and set 156),) transistor 43 to O.
N, the no-pass air passage 31 is opened and air is replenished (157).

When this state continues, the values of Fl and F2 are F1=
1. It is determined that F2=O (153, 158), and to measure its duration, calculate Ca1r=Ca1r -1 (159)), and after a predetermined time or after a predetermined rotation (Ca
To judge the value of ir, set it to 160) (when z Ca1r≦0), set F2=1, and set (161)
,) Bypass air passage 3 with Runcisor 43 turned OFF
1 is closed (162).

Then, when the bypass air passage 31 is closed in this way, it is determined as F2-1 until either condition 1 or 2 is satisfied (158), so the bypass air passage 31 is closed as it is. It will remain as it is.

After that, if either condition 1 or 2 is no longer satisfied, F
1-0, and when conditions 1 and 2 are satisfied, control toward the lean side can be performed by replenishing air. Then, the engine speed N is transferred to the memory for each calculation (16
3).

As explained above, according to the present invention, when the engine speed decreases due to the connection of the throttle valve when the special throttle valve for deceleration operation is fully closed, the bypass passage provided by bypassing the throttle valve and the throttle valve is opened. Since the air-fuel ratio is subjected to lean correction control by replenishing intake air, a decrease in torque can be prevented, and engine stalling and other malfunctions of the engine can be effectively prevented.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing the fuel system of a conventional mixture control device for an internal combustion engine, Figure 2 is a configuration diagram showing the air system and electronic control system of the same device, and Figure 3 is a configuration diagram showing the fuel injection amount in the same device. Figure 4 is a diagram showing the battery voltage correction characteristic, Figure 4 is a diagram showing the cooling water temperature increase correction characteristic, Figure 5 is a diagram showing the increase correction characteristic after starting, and Figure 6 is the graph showing the increase correction characteristic after idling. Figure 7 is a diagram showing the cooling water temperature correction characteristic at startup, Figure 8 is a diagram showing the engine rotation speed compensation characteristic at startup, and Figure 9 is a diagram showing the engine speed compensation characteristic at startup. Diagram showing the post-elapsed time correction characteristics, Figure 10 fat
, (bl, (cl, (di) is a diagram showing various characteristics of the same device under predetermined operating conditions, No. 1154 is an overall configuration diagram showing one embodiment of the present invention, and Fig. 12 is a mixture of the above embodiment. 13 to 16 are flowcharts showing different control system embodiments of the control system. 6. Engine 9. Intake manifold 10
... Injector 11 ... Control controller, 2. ] 1 - ] 5 ... Air flow meter 17 ... Throat valve 31 ... Bypass air passage 32.
... Solenoid control valve 33 ... Rotation speed sensor + 34 ...
Reference (signal) generator 35...Vehicle speed sensor 36...
・Thalassochi Isochi 37...neutral switch
38...Rehearsing switch 39...Arithmetic circuit 40.41...Pulse counter 42...Memory 43...Transistor 44...Hasoteri patent applicant Nissan Motor Co., Ltd. agent Patent attorney Fujio Sasashima

Claims (1)

[Claims] Detects the engine speed (N) and the amount of air (Q) taken into the intake passage upstream of the engine's throttle valve.
In an internal combustion engine air-fuel mixture control device that controls the air-fuel ratio of the air-fuel mixture by supplying an amount of fuel corresponding to /N to an intake passage as a basic supply amount, means for detecting that a vehicle is decelerated. A bypass air passage bypassing the throttle valve and supplying air to the intake passage, and a means for opening and closing the bypass air passage are provided, and when the vehicle is decelerated t'A, the bypass air passage is opened and the intake passage is opened. 1. An air mixture control device for an internal combustion engine, comprising an air amount control means for replenishing air.