JPS61116045A - Number of idle revolutions control device for electronic control fuel injection internal-combustion engine - Google Patents

Abstract

PURPOSE:To provide the optimum number of revolutions suitable to an air conditioning condition, by a method wherein an on-off type air conditioning idle up control valve and a rotary type idle speed control valve are located in parallel on a bypass passage being installed in a manner to run around a throttle valve in a suction pipe. CONSTITUTION:By pass passages 3 and 3' are installed in a manner to run around a throttle valve 2 in a suction pipe 1 in an engine, and an on-off type air conditioner idle up control valve 5, which is opened during operation of an air conditioner 4 and closed during stop, is located on the bypass passage 3. A rotary type idle speed control valve 6, being capable of continuously changing a flow rate, is located on the bypass passage 3'. During air-conditioning operation in that an air conditioner switch SW1 is made, the idle speed control valve 6 is adapted to perform open loop control according to an air-conditioning condition by means of an open loop control means 7. During the open loop control, an open loop control desired value during open loop control is corrected by means of learning through the operation of a learning means 8 during given operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an idle speed control device for an electronically controlled fuel injection internal combustion engine.

Conventional technology In electronically controlled fuel injection internal combustion engines, a bypass passage is provided in the intake pipe to bypass the throttle valve in order to control the engine speed during idling operation, and an idle speed control valve (ESC valve) is installed in the bypass passage. are doing. The opening degree of the idle speed control valve is controlled so that an engine speed corresponding to predetermined air conditioning conditions is obtained. Conventionally, such an idle speed control valve employing a step-7 motor is known. However, although this method using a step motor improves control accuracy, it has the drawback of slow response speed. Therefore, a rotary type idle speed control valve has recently been proposed. In this rotary type idle speed control valve, the rotational drive solenoid applies rotational driving force to the valve body according to the current, and when the valve body is balanced with the spring force of the torsion spring, the valve body stops and obtains the opening degree according to the solenoid current. It is. This low-rise type idle speed control valve has the advantage of quick response.

Problems to be Solved by the Invention Since the step motor type idle speed control valve has a wide controllable range of flow rate, it is common to have a so-called idle-up function when the air engine operates. However, in the case of the Rokuri type, it is difficult to widen the flow rate range. In a rotary type idle speed control valve, the solenoid has a winding that drives the valve body in the opening direction and a winding that drives the valve body in the closing direction. A bimetallic stopper means is provided as a guard means to restrict the opening range of the valve body.
The upper and lower limits of the opening degree of the valve body are regulated according to the temperature. If the idle speed control valve is to have an idle up function, the guard range of the bimetal must be widened. If this happens, it will no longer function as a guard.

Means for Solving the Problems As shown in FIG. 1, according to the present invention, a bypass passage 3. is provided in the intake pipe 1 of the engine so as to bypass the throttle valve 2.
3', and the bypass passage 3 includes an on-off type air conditioner idle-up control valve 5 that is opened when the air conditioner 4 is activated and closed when it is stopped, and a low-pressure type idle speed control valve 6 whose flow rate is continuously variable. are installed in parallel, and an idle speed control valve 6 is installed in parallel to obtain the engine rotation speed according to the air conditioning conditions.
An idle speed control device is provided which includes an open loop control means 7 for controlling. Preferably, a learning means 8 is provided for correcting the open loop control target value by learning during a predetermined operation.

The open-loop control means 7 performs open-loop control of the opening degree of the idle speed control valve 6 when the air conditioner switch SW is turned on and the idle speed control valve 6 is activated in accordance with the air conditioning conditions, such as the cabin temperature and the air conditioner pro-switch position. The learning means 8 corrects the target value of the open-loop control by comparing the actual engine speed and the measured engine speed during a predetermined operation such as immediately after driving and stopping, or after starting and after warming up. However, this value will be used during the next open loop control.

In FIG. 2 of the embodiment, 12 is an air cleaner, 14 is an air flow meter, 16 is a throttle valve, 18 is a surge tank,
20 is an engine body, 22 is a fuel injection valve for each cylinder, 24 is a distributor, and 26 is a transmission. Since these are all well-known components for an electronically controlled fuel injection internal combustion engine, a detailed explanation of the connection relationship will be omitted.

A bypass passage 28 is provided so as to bypass the throttle valve 16, and the bypass passage 2 has branch portions, 28", 28
” to the surge tank 18. A negative pressure operated idle up control valve 3 is connected to the bypass passage branch 28”.
0 is set. The idle-up control valve 30 is connected to a diaphragm 32, and a spring 34 exerts a biasing force in a direction to close the control valve 30. The three-way switching solenoid valve 36 is operated by the air conditioner control amplifier 44 to switch between a white position that communicates the diaphragm 32 with the air filter 38 and a black position that communicates the diaphragm 32 with the negative pressure boat 40 of the surge tank 18. Driven. The same amplifier 44 also drives a compressor 46. That is, when the air conditioner switch SWI is turned on, the amplifier 44 starts operating the air conditioner compressor 46, and the three-way solenoid valve 36 starts operating.
is the blacked position, the negative pressure of the negative pressure port 40 acts on the diaphragm 32, and the idle amplifier control valve 30 opens,
Idle up is performed. Air conditioner switch SW1 is O
When the FF is on, the air conditioner compressor 46 is stopped, the solenoid valve 36 is at the self-destructive position, atmospheric pressure acts on the diaphragm 32, the idle amplifier control valve 30 is closed, and idle-up is not performed.

50 is a rotary type idle speed control valve, which is installed above the second branch 28' of the bypass passage 28. The control valve 50 has a detailed configuration as shown in FIG. 3.4. A cylindrical valve opening 53 is formed in the housing 51;
A valve body 54 is rotatably disposed in this valve opening 53. The valve body 54 includes a valve member 54a and its upper and lower end plates 54b.
It consists of An inlet vibrator 57 and an outlet vibrator 58 are inserted into the housing 51 so as to form an angle of 180°, and the valve opening 5
3, air is inflowed as shown by the arrow j1, and air is taken out as shown by the arrow j2. End plate 5 of valve body 54
A rotating shaft 59 is attached to 4b, and the upper and lower ends of the rotating shaft 59 are pivotally supported by the housing 51 by bearings 60 and 61. A magnet 63 having a circular cross section is fixed on the rotating shaft 59, and a winding 64 is arranged with the magnet 60 sandwiched therebetween. Winding 64.
65 form magnetic fluxes in opposite directions as Nj and N2, respectively, in FIG. 5, thereby urging the magnets 63 to rotate in opposite directions as indicated by arrows f1 and f2, respectively. Therefore, the valve body 54 is connected to the arrow r1. It is urged to rotate in the direction according to r2. The rotating shaft 59 is hollow, through which a torsion spring 67 such as a piano wire is inserted, and the lower end is connected to the housing by the third
(Figure), and the upper end is fixed to the rotating shaft at p2. A constant period pulse signal current is applied to the windings 64 and 65 from a drive circuit, which will be described later, to alternately drive these windings. The magnet 63 is rotated more in the C1 direction or more in the C2 direction according to the ratio of the driving time of each winding to the period of the pulse signal (so-called duty ratio).
As a result, in FIG. 4, the valve body enters as shown by the solid line between the fully closed position where it separates the donkey vibe 57 and the outlet vibe 58, and the fully open position where it enters as shown by the broken line 54' and communicates the donkey vibe 57 and the outlet vibe 58. will move according to the duty ratio. Conversely, the flow rate of air passing through the idle speed control valve 50 is controlled according to the duty ratio.

See Figure 6.

The idle speed control valve 50 further includes a bimetallic safety (guard) mechanism. This safety mechanism consists of a coiled bimetal 70 disposed at the bottom of the housing 51 and a guard plate 71 fixed to the lower end of the rotating shaft 59. The outer end 70' of the bimetal 70 is fixed to the housing-side piece 72 by a screw 73, and the inner end 70' is free and located in a notch 71'' formed in the guard plate 71. Therefore, the rotation angle of the guard plate 71, in other words, the valve body 54 connected to the rotating shaft 59, can be achieved within a range in which the opposing inner surface of the guard plate notch 71' does not come into contact with the bimetal free end 70'. By regulating the rotation angle range of the valve body 54 in this way, even if the winding 64 or 65 should be disconnected, the intake air amount of the engine can be prevented from becoming significantly excessive or insufficient. A water jacket 75 (Fig. 3) is formed around the bimetal 70 at the bottom of the housing 51, a hot water vibrator 76 is attached to the water jacket 75, and the hot water pipe 76 is connected to the engine body 20.
The engine cooling water is introduced into the water jacket 75 by communicating with a water tank (not shown) in the water jacket 75 . Therefore, the bimetal 70 expands and contracts in accordance with the engine temperature as shown by the arrow g in FIG.
Control as shown. That is, as the engine temperature increases (as the engine warms up), the required air amount decreases, and the flow rate control range accordingly shifts to the low flow rate side.

In FIG. 2, reference numeral 80 indicates a control circuit for controlling the operation of the idle speed control valve 50, which forms an operation signal to the idle speed control valve 50 based on signals from sensors that detect various operating conditions. The control circuit 80 is configured as a microcomputer system, and includes a microprocessing unit (MPU) 81, a memory 82, an input port 83, an output port 84, and a bus that interconnects these and transfers data and instructions. It consists of 85. The input port 83 receives signals from the following sensors. Air flow meter 14 produces a signal relating to the amount of intake air Q. The throttle valve 16 is connected to a throttle switch SW87 and generates a signal LL indicating the idle opening degree of the throttle valve 16. A rotation speed sensor 89 is provided so as to face the rotating magnet 24b on the distribution shaft 24a of the distributor 24, and generates a signal corresponding to the engine rotation speed NE. A vehicle speed sensor 90 is provided in the transmission 26 and generates a signal corresponding to the rotational speed of the output shaft of the transmission, that is, the vehicle speed SPD. Water temperature sensor 91 in engine body 20
is provided to generate a signal THW depending on the engine water temperature. The air conditioner amplifier 44 outputs a signal A/indicating the operation of the air conditioner.
C is input. There is a sensor that detects the position of the lever 93 when operating the air conditioner operation panel 92 in the vehicle interior.
Signals LO1MED and HI are generated according to the low air volume position, intermediate air volume position, and high air volume position of No. 3.

Further, the vehicle room temperature sensor 94 generates a signal corresponding to the temperature THR in the vehicle interior.

The MPU 81 uses the signals from these sensors to form a duty signal according to a program described later and sends it to the output port 8.
4 to the QISC valve drive circuit 96. Figure 8 is I
The SO valve driving circuit 96 is shown, and includes transistors T1 and T2 whose bases and emitters are connected in series to the windings 64 and 65 of the idle speed control valve 50, and an inverter I connected to the base of one transistor T1. Become.

The duty signal DUTY is applied to the transistors TI and T2 from the output port 84, the transistor T1 is turned on when the duty signal is at the low level, and the transistor T1 is turned on when the duty signal is at the Ht and gh levels. The cycle F of the duty signal is constant, but the duration X of the high level is varied. This causes the windings 64, 65 to be alternately energized, resulting in the idle speed control valve 50 depending on the duty ratio x/F.
Opening control is realized.

The control circuit has hardware and software for controlling the fuel injector 22. Since this is not related to the features of the present invention, a detailed explanation will be omitted, but as is well known, the MPU 81 receives the intake air amount Q from the air flow meter 14 and the engine rotational speed from the rotational speed sensor 89 according to the program in the memory 82. The fuel injection amount is calculated from NE and other signals and sent to the output port 84. Drive circuit 9
8, the fuel injection valve 22 is driven so that the calculated amount of fuel is injected.

Next, software for controlling the idle speed of the present invention will be explained with reference to the flowchart shown in FIG. The operation of the present invention will also be clear from the explanation of this flowchart. In FIG. 9, 100 indicates the start of the idle speed control routine, and M
Execution is started when an interrupt signal is applied to the interrupt port of the PU 81. In step 102, MPU
81 is the throttle opening signal L of the throttle switch 87
L is loaded and it is determined whether the throttle valve 16 is at the idle position. If it is in the idle position, it is determined as Yes, and 1
Proceed to step 04. In this step, the vehicle speed sensor 9
A vehicle speed signal SPD from 0 is loaded and it is determined whether the vehicle is moving, for example whether SPD is greater than 2.5 km/hour. If No, it is determined that the engine is idling.

At 106, it is determined whether the air conditioner operating state flag AC5W is 1 or not. Here flag AC3W is air conditioner signal A/C
1 when the air conditioner compressor 46 is operating.
, is set to O during the stop (Fig. 11(a)). If the air conditioner is stopped, the process branches to No, and the closed loop control routine during normal idling operation when the air conditioner is not operating is executed. 108 is the set idle speed NF when the air conditioner is not operating
A determination is made as to whether the rotational speed NE actually measured by the rotational speed sensor 89 is greater than or equal to the rotational speed NE. The rotation speed NE is the set value NF.

If it is larger, proceed to step 110 and reduce the air conditioner non-operation duty ratio equivalent value DUTY'' by 7%, and if the rotation speed NE is smaller than the set value NFo, proceed to step 112 and increase DUTY'' by α%. . Step output 114 stores the value of DUTY' in the memory area of DG. As will be described later, this DC is the opening degree reduction compensation bone (D
This is the base learning value that is added to AC). In step 116, since the air conditioner is not operating, the correction value DA is
C is assumed to be zero. In step 118, from DG to DAC
The duty ratio DUTY is obtained by subtracting . D.A.
Since C is set to zero at step 116, the value of DUTY is 110 or 1 during this closed loop control when the air conditioner is not operating.
It matches DUTY' calculated in step 12.

This duty ratio data is set to the output port 84. As a result, in the drive circuit 9G, the transistors T1 and T2 are alternately turned on, and the windings 64 and 65 are alternately driven. Therefore, the idle speed control valve 50 takes an opening degree according to the duty ratio. Through such closed loop control, the rotational speed when the air conditioner is not in operation is controlled to a set value NFo (for example, 650 rpm) as shown in A in FIG. 11(b). When the air conditioner is not operating, the air conditioner switch SWI is OFF, so the solenoid valve 36 takes the white position, and atmospheric pressure acts on the diaphragm 32, so the idle amplifier control valve 30
is closed (FIG. 11 (c)), and the flow rate of the idle speed control valve 50 at this time is DG (2). The control state is closed loop control (e).

When the air conditioner switch SWI is turned on to switch the air conditioner from stop to operation at time tl in FIG. 11, the air conditioner amplifier 44 switches the solenoid valve 36 to the black position,
The negative pressure of the negative pressure boat acts on the diaphragm 32 and the idle up control valve 30 opens (FIG. 11(c)). Air is therefore introduced into the surge tank 18 via the bypass passage 28, 28'. Then, the engine speed rapidly increases as shown in B of the same figure (d). At time t1 when the air conditioner is switched from stop to start, flag AC3W switches to 1 (a)
, the determination at 106 in FIG. 9 becomes Yes, and the process proceeds to the open loop control routine when the idle is up at 120 or less. 120
In the step, calculation of the idle speed control valve opening reduction correction amount DAC corresponding to the necessary increase in rotational speed due to air conditioner operation is executed. As shown in FIG. 12, in the memory 82 there is a map of correction values DAC for obtaining a set rotational speed according to the vehicle interior temperature T)tR, and the DAC value corresponding to the temperature is interpolated. In step 124, a learning correction value a of the idle rotation speed during operation of the air conditioner, which is calculated by a learning routine described later, is added to the vehicle interior temperature THR. Next, the process goes to step 118, where a learning base value D is determined to set the rotation speed to a predetermined value in closed loop control when the air conditioner is activated.
D is obtained by subtracting the idle up correction amount DAC from G.
It is considered UTY. As a result, the opening degree of the idle speed control valve is modified in accordance with the cabin temperature THR. As mentioned above, since the duty ratio and the opening degree of the idle speed control valve correspond (Fig. 6), the rotation speed when the air conditioner is activated changes depending on the temperature THR of the passenger compartment (Fig. 11 (B)). It is controlled as shown in C. For example, depending on whether the temperature in the vehicle compartment is high, medium, or low, the DAC changes from low to high as shown in Figure 12 (d), and the idle speed changes from 950 rpm to 850 rpm.
, 750 rpm. As described above, during normal operation of the air conditioner, open-loop control of the engine speed is performed according to the temperature THR of the passenger compartment (FIG. 11(c)).

When the switch SWI is turned OFF to stop the air conditioner at point 2 in FIG. 11, the idle-up control valve is instantaneously closed as shown in (c), and the judgment at 106 in FIG. 9 becomes Yes. Enter normal closed loop control. At this time D
Since AC is zero, the set opening of the idle speed control valve rapidly increases to DG (X in FIG. 11(d)). Since the rotary type has a quick response, it can easily follow such a sudden increase, and the rotational speed is quickly controlled to the set value NFO when the air conditioner is not operating, and no stall occurs.

FIG. 10 shows a learning correction routine for the idle-up correction DAC in open loop control when the air conditioner is activated. This is a time interrupt routine that is executed every fixed period of time (for example, 32 msec). At 202, data from the vehicle speed sensor 90 is loaded, and it is determined whether the vehicle is stopped. If the vehicle is not stopped, the process branches to No, and the learning permission flag X5PD is set.

When the vehicle stops, the judgment of 202 switches to No, and 2
Proceeding to step 06, it is determined whether the learning permission flag X5PD is 1 or not. In the first routine after the vehicle stops, the flag X5PD is 1, the determination at 206 is Yes, and the process proceeds to 208. In step 208, it is determined whether the temperature from a sensor that detects the warm-up state of the engine, such as the sensor 91 that detects the temperature of engine cooling water, has reached a temperature that corresponds to when the engine is warmed up. If the water temperature rHw is, for example, 80° C. or higher, it is determined that warm-up is required, and the process proceeds to 210. At 210, it is determined from the LL signal from the throttle sensor 87 whether it is an idle opening loop control unit. In addition, at 211, the air conditioner operation flag A
It is determined whether C3W is 1 or not. 208.210 and 21
A determination of Yes in both cases 1 indicates idling operation in which the engine is warmed up and the air conditioner is activated, and it is determined that this is a condition that may be learned.

At 212, the learning permission flag X5PD is reset, and at 212, the learning permission flag X5PD is reset.
At step 14, the set rotational speed NT corresponding to the cabin temperature THR at that time is mapped. The set rotational speed NT with respect to the temperature T and HR of the vehicle compartment is as shown in the graph of Fig. 13.
A map corresponding to this graph is stored in the memory 82, and the MPU 81 calculates the set rotation speed NT at that time with respect to the detected cabin temperature THR by interpolation. 216
In step , the actual rotational speed NE and the set rotational speed NT are compared. If the set rotation speed NE is smaller than the actual rotation speed, the process proceeds to step 218, and the learning correction value a is set to 0.5.
% will be reduced. Conversely, if the set rotational speed NT is greater than the measured rotational speed, the learning correction value a is increased by 0.5%. This learning correction value a is added to the DAC during open loop control while the air conditioner is operating in the routine of FIG. 9 (step 124).

Through such learning, idle operation when the air conditioner is activated will not deviate from the set value regardless of open loop control.

The learning permission flag X5PD is reset at 206 in the next routine. Therefore, as shown in FIG. 14, the flag X5PD is set while the vehicle is running, is set only when the routine is executed for the first time after stopping, and is set down thereafter.

That is, the learning correction of a is performed only when the vehicle is stopped.

The implementation shown in FIG. 15 is a modification of step 120 in FIG.
, , the value of the DAC is changed according to Hl. There are no other differences.

A normal idle-up control valve has an adjustment screw 200 at 202 in Fig. 2 for fine adjustment of the rotation speed during idle amplifier.
It is installed along the route shown in . In this invention, since the idle speed control valve is controlled in an open loop, the adjustment screw 20
0 is moved, the operation of the idle speed control valve is irrelevant, and the idle amplifier rotation speed can be adjusted by the screw 200. Furthermore, since closed-loop corrections through learning are limited to one time immediately after the vehicle starts running,
Learning is not performed when operating the idle amplifier adjustment screw, so the rotational speed will not become unfocused. Note that the timing at which learning is performed is not limited to the example;
This can be done during idling operation when the air conditioner is operated and there is no risk of it being touched by zero. For example, it can be done only once immediately after the engine is started, and various other possibilities are possible.

Effects of the Invention According to this invention, by using the idle up control valve and the rotary idle speed control valve together, the idler knob can be modified to suit the operating conditions of the air conditioner. The optimal rotation speed can be obtained, and the fuel consumption rate can be improved. Furthermore, the width of the guard of the bimetal 70 can be made smaller than when a single idle speed control valve supplies the necessary air even when the air conditioner is operating. Even if the idle speed control valve malfunctions, the flow rate shared by the control valve is small, so that the engine speed will not be greatly deviated.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the present invention. FIG. 2 is a diagram showing the configuration of the embodiment. FIG. 3 is a longitudinal sectional view of the idle speed control valve. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a perspective view showing the principle of construction of the idle speed control valve. FIG. 6 is a graph showing the air flow rate characteristics with respect to the duty ratio of the idle speed control valve. FIG. 7 is a graph showing the bimetal guard characteristics of the idle speed control valve. FIG. 8 is a diagram showing the drive circuit configuration of the idle speed control valve. FIGS. 9 and 10 are flowcharts illustrating the software configuration of the present invention. FIG. 11 is a timing diagram. FIG. 12 is a graph showing a change in the idle speed control valve opening degree correction DAC during idle up with respect to the temperature of the vehicle interior. FIG. 13 is a graph showing changes in the set engine speed with respect to the cabin temperature during idle amplification. FIG. 14 is a graph showing changes in vehicle speed and changes in the learning permission flag. FIG. 15 shows another embodiment for changing the set number of times. 16...Throttle valve 22...Fuel injection valve 28...Bypass passage 30...Idle up control valve 46...Air conditioner compressor 50...Idle speed control valve 80...Control circuit

Claims (1)

[Claims] In an electronically controlled fuel injection internal combustion engine, a bypass passage is provided in the intake pipe of the engine to bypass a throttle valve, and an on-off type air conditioner idle-up control valve is provided in the bypass passage, which is opened when the air conditioner is activated and closed when the air conditioner is stopped. and a rotary-type idle speed control valve with a continuously variable flow rate are installed in parallel, and the idle speed control valve is equipped with an open-loop control means that controls the idle speed control valve so that an engine speed corresponding to the air conditioning conditions is obtained. Device.