JPS59115448A - Controller for intake air amount of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the engine brake performance and fuel consumption by controlling an idle-speed control valve by a certain value towards the closure side for a certain time after a throttle valve is perfectly closed, if a car-speed is higher than a set value, in the captioned apparatus. CONSTITUTION:An intake-air amount controller is equipped with an electromagnetic-type air control valve 50 which is installed in an idle air by-pass 48 which by-passes a throttle valve 32 and controls the intake air according to the duty ratio of a pulse signal and a means for setting the fundamental control value having the duty ratio of the pulse signal according to the number of revolution of the engine. Further, said controller is equipped with a correction means for the increased amount for the fundamental control value at the time when the throttle valve 32 is perfectly closed, a means for reduction-controls the fundamental control value for a certain time from the time when the throttle valve 32 is perfectly closed in the case when the car-speed is over a set value, and a means for transmitting a pulse signal into the electromagnetic-type air control valve 50.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the control of the amount of intake air in an automobile engine, and more specifically, the present invention relates to the control of the amount of intake air in an automobile engine, and more particularly, to the -Relates to an electronic intake air control device comprising an off-operation air control valve (idle speed control valve).

Electronically controlled fuel injection systems (EFI) can control the air-fuel ratio of the combustion mixture according to various requirements, and are now being used as fuel supply systems for automobile engines from the viewpoint of purifying exhaust gas and improving fuel economy. It is often used in place of a vaporizer. In the EFI system called the L-Jetronic system, the fuel injection amount is calculated by the device's microcomputer according to the intake air amount measured by an air flow meter installed in the intake system, and a predetermined amount of fuel is injected. is injected into intake air by an injector to form a combustion mixture. The amount of intake air is controlled by a throttle valve linked to the vehicle's accelerator pedal. The idle speed of the engine is determined by the amount of intake air that flows through the gap between the slot valve and the throttle valve when the throttle valve is fully closed.Dust adheres to this gap as the engine is operated for a long period of time. Therefore, the amount of intake air during idling decreases over time, which causes the engine's idling speed to decrease. Furthermore, the idle speed may change over time as the engine internal resistance decreases after the new engine has finished its break-in. Furthermore, in a vehicle equipped with a near conditioner, torque converter, four-wheel steering, etc., the amount of air at idle must be added when these devices are operated. Therefore, the conventional EF
In an engine with an I device, is it possible to adjust the throttle valve by air? An air control valve is installed in this pi/thousand passage, and by controlling the operation of this air control valve, the amount of intake air at idle is adjusted, thereby bringing the idle speed to the target value. It's under control.

In this specification, such an idle air pipe 14' space passage is referred to as an "air torque control passage",
The air control valve will also be referred to as ``1 idle speed control valve'' or simply ``rIscv''.

There are three types of conventionally used 15CVs: a negative pressure operated type, a step motor type, and an on/off type with a linear solenoid. The present invention relates to the latter linear solenoid type 15CV, and this type of 15CV is turned on/off by being supplied with a pulsed drive current from an electronic control unit (ECU) mounted on an automobile. The flow rate of idle air through the 15CV is proportional to the "duty ratio," which is the percentage of time that -f malus flow is actually provided within a unit of time. Therefore, if the data ratio is calculated to an appropriate value by the microprocessor of the electronic control unit (ECU), the idle speed can be controlled to the target value. The obtained duty ratio is transferred to the output register of the microprocessor and outputted to the rscv as a malus signal having a predetermined duty ratio.

The 15CV is also used to provide the idle speed 1x control passage with functionality similar to a mechanical dashpot. That is, if the throttle valve is suddenly closed during deceleration, the air-fuel mixture becomes overrich, causing engine stall or unburned gas being discharged. Therefore,
Conventionally, when the throttle valve is fully closed while driving under a certain load, the
3 seconds), the I5CV is opened extra to increase the amount of intake air passing through the ISCV.

However, when the vehicle speed is high, the engine speed is also high,
′! , Since the engine is rotationally driven by the drive system,
Even without the dashpot function, there is no risk of engine stalling. However, operating the dashpot when the vehicle speed is high causes problems such as unnecessary air being sucked in, which worsens the engine braking effect and worsens fuel efficiency.

Furthermore, the opening degree of IsCν is generally feedback-controlled according to the engine speed when the engine is idling, and while the vehicle is running, the l5CV stores the opening degree at the time of feedback control in memory and uses only that opening degree. However, since the ISCV is open during driving, the effectiveness of engine braking may be reduced.

The present invention was devised in view of the problems of the prior art, and it is an object of the present invention to provide an intake air amount control device that can improve engine braking performance and improve fuel efficiency.

Therefore, the present invention provides that when the vehicle speed is higher than the set value, the IS
The purpose is to control CV to the closed side by a certain value.

For this reason, the intake air amount control device of the present invention is provided with a throttle valve of an internal combustion engine in a bypass passage/pass and adjusts the intake air flowing through the bypass passage according to the duty ratio of a pulse signal.・An off-action type electromagnetic air control valve, ・Basic control value setting means for setting the basic control value of the duty ratio of the Mars signal according to the rotation speed of the engine, and a basic control value setting means for setting the basic control value of the duty ratio of the Mars signal, basic control value increase correction means for adding an increase correction value to the basic control value over a predetermined time when the throttle valve is fully closed when the vehicle speed is equal to or higher than a set value; a reduction correction means for reducing and correcting the basic control value over a second predetermined period of time; and output means for outputting to the air control valve.

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

FIG. 1 is a schematic diagram of an electronically controlled fuel injection engine equipped with an intake air amount control device of the present invention. The engine intake system has an air flow meter housing 10 connected to an air cleaner (not shown). Intake pipe 12, surge tank 14. Intake manifold 1, β.

It consists of an intake port 18, and an injector 2o is installed in the intake manifold 16 for each cylinder. The injector 20 is connected to a pressurized fuel supply system (not shown), and opens in response to a signal output from an electronic control unit (ECU) 30 to inject a predetermined amount of fuel into the intake air. It is designed so that a mixture for combustion can be formed.

The intake pipe 12 is provided with a tough throttle valve 32 that is linked to the vehicle's accelerator pedal.
A well-known throttle position sensor 34 having a plurality of contacts is connected to the shaft of No. 2, and is capable of outputting a signal corresponding to the throttle opening to the electronic control unit 30.

The air flow meter housing 1o is provided with a measuring plate 36 for measuring the intake flow rate, the latter being 36V.
: and are connected to a potentiometer-type intake air amount sensor 38, which sends a signal according to the intake air amount to the electronic control unit 3.
0 can be output.

An idle speed control passage 48 is provided between the intake pipe 12 and the surge tank 14, bypassing the throttle valve 32, so that even when the throttle valve 32 is fully closed, intake air can still flow through the passage 48. It is designed to be supplied to the engine. This passage 48 is provided with an on/off type electromagnetic air control valve, ie, an idle speed control valve (ISCV) 50, so that the amount of intake air flowing through the passage 48 can be controlled. This air control valve (l5CV) 50 is controlled on and off by a gust-like drive current output from the electronic control unit 30, and the amount of intake air depends on the duty ratio of the input pulse signal.

The IJ computer 52 is provided with a known rotation angle sensor, and is capable of outputting a signal to the electronic control unit 30 in accordance with the angular position and rotational speed of the engine crankshaft. 56 is a cylinder block, 58 is a piston, 60 is an exhaust manifold, and 62 is a vehicle speed sensor.

FIG. 2 is a block diagram of the electronic control unit (ECU) 30 shown in FIG. 1, and 1ECU 3O is a program-controlled microcomputer. Electronic control unit (E
The ECU) 30 is a microprocessor (
MPU) 70 and a read-only memory IJ (ROM) that stores programs for calculation processing and calculation constants.
72, a random access memory (RAM) 74 consisting of a non-volatile storage section and a volatile storage section, and a clock 76 that generates various clock signals. MPU
70, ROM72, and RAM 741d common/sub8
The clock 76 is connected to the MPU
It is connected to MPU 70 and sends a clock signal directly to MPU 70.

The analog signal from the air flow meter 38 is sent to the buffer 8.
0 and A/D converter 84 via multiplexer 82
is input to the input/output port 8, converted to a digital signal, and sent to input/output port 8.
6 and the common path 78 to the MPU 70.

A signal from the throttle position sensor 34 is read into the MPU 70 via an input port 88, and is input to the vehicle speed sensor 62.
The signals from the rotation angle sensor 54 are read into the MPU 70 via the shaping circuit 90 and the input port 88, respectively.

Based on the data read from each sensor and stored in the RAM 74, the MPU 70 calculates the duty ratio of 15CV by performing arithmetic processing, which will be described later, in accordance with the program stored in the ROM 72. Similarly, it is transferred to a register in the MPU 70, and is down-counted by the clock signal from the clock 76, and sent as a signal with a desired duty ratio to the drive circuit 92 via the output port 9°, where it is amplified. and is supplied to the l5CV 50 in the form of a driving current.

FIG. 3 is a flowchart of a program for calculating the duty ratio of r scv. This duty ratio calculation routine is an interrupt routine started by a signal from the rotation angle sensor 54, and is executed every revolution of the crankshaft. It is something that will be done.

In Stella f101, this is the learned value of the duty ratio recorded in the non-volatile RAM of the RAM 74 in the previous routine. is read and moved to volatile RAM. Step 102 is a step for determining whether or not the engine is under conditions that allow feed control of the l5CV50.
For example, the starter switch is turned OFF by determining the starter switch, engine cooling water temperature, vehicle speed, and throttle opening.
F. When the cooling water temperature is above the set value, the vehicle speed is zero, and the throttle valve is fully closed, proceed to step 103 and below, and proceed to step 15.
Feedback control of CV50 is performed. If the starter is operating, the coolant temperature is below the set value, the vehicle speed is high, or the throttle valve is open, the step
Below 201, the 15CV 50 is controlled by open Luso.

If the feedback condition is satisfied, in step 103, a target idle speed NF of the engine is selected depending on the operating state of accessory devices such as a near conditioner and a torque converter. That is, when the near conditioner's fungus reseller is being driven or when the torque converter is in the drive range, the engine load at idle changes, so a different target idle speed NF is selected.

In step 104, the difference IME-NFI between the current engine speed NE and the target engine speed NF is calculated. In order to feedback-control l5CV50 by proportional-integral operation based on lNg-NFI obtained in this way, steps 105 to 111 perform a procedure for calculating the following equation.

D=D1+DP+DT・・・・・・・・・・・・・・・
(1) Here, D is the final duty ratio of the pulse current applied to 15CV50, Dl is the integral term of the duty ratio, DP is the proportional term, and D is the prospective term. Integral term DI
The reason for using this is to take the duty ratio of the previous routine (the routine in Figure 3 is executed every revolution of the crankshaft as mentioned above) and use it as a starting point to correct the duty ratio. The proportional term DP was used to quickly recover when the control target rotation speed significantly overshoots or undershoots, and the prospective term DT is used to quickly recover when a load is applied to the near conditioner, torque converter, etc. This is to bring the rotation speed closer to the target value.

That is, in step 105, the correction amount ΔD1 of the integral term DI is R
Read from OM72. For this reason, a map as shown in FIG. 4(a) is stored in advance in the ROM 72 in the form of a table. For example, NE is 690 (rpm) and NF is 700 (rpm), so IME-NFl=
10 (rpm), ΔD1 can be set to o, o2 (%) ◎ In step 106, the integral term of the previous routine, II
The current Dl is obtained by adding the C correction amount ΔD1 (D, ←D1
+ΔD, ).

Next, in step 107, l obtained in step 104 is
A proportional term is read from the ROM 72 based on Ng-NFI. For this reason, a map shown in FIG. 4(b) is previously stored in the ROM 72 in the form of a table. This map is, for example, l NE-NF 1= 100 (r
pm), Dp can be set to 0.5C%). Figure 4(a)? As is clear from comparing the map in (b), D shown in Fig. 4(b),
The map has a linear portion at .DELTA.D1 shown in FIG. Therefore, ΔD1 is suitable for slightly correcting Dl, and D is suitable for quickly correcting the duty ratio when the deviation between the current rotation speed and the target rotation speed (i.e., INB-NFI) is large. suitable for

In step 108, the ROM is stored in advance in accordance with the operating state of the near conditioner and the shift state of the torque converter.
The prospective term DT is read from a similar map stored in 72.

In step 109, +DP is calculated and the sum is the learned value of the duty ratio. (Do ← D engineering + DP).

Then, in step 110, this learning value is determined. If RAM7
The previous routine D is stored in a predetermined area of the non-volatile RAM of No. 4. is updated. The learned value is stored in the non-volatile RAM in this way. is used during open loop control, which will be described later.

Next, in step 111, calculation of equation (1) is performed,
The obtained final duty ratio is determined by MP in step 112.
Moved to register U 70. The procedures of steps 101 to 112 described above are not substantially different from conventional feedback control programs.

Next, control of intake air amount during open loop of the present invention,
That is, a control program with a dashpot function will be described. When it is determined in step 102 that the feedback condition is not satisfied, the process proceeds to Stella f201, where it is determined whether or not the throttle valve is fully closed. If it is not fully closed, the process proceeds to Stella 7D202, and if it is fully closed, the process proceeds to step 209.

In the Stella 7° 202, the intake air amount Q measured by the air flow meter 38 and the engine rotation speed N detected by the rotation angle sensor 54 are used to set the intake air per engine rotation -tQ/N to a set value, for example, 0. , 31/rev or not. Since Q/N corresponds to the engine load, it is determined whether the engine load is medium load or not.

If Q/N<0.31/rev, Stella 7'204
If Q/N≧0.371/rev, the value of the load discrimination counter C is set to 250. This load discrimination counter C is constructed using a predetermined area of the RAM 74, and as shown in FIG.
4m ae e due to the interrupt routine executed every time
The number is decremented each time.

Therefore, in step 203, the value of counter C is 25.
Even if it is set to 0, if the state of Q/N < 0.37/rev continues for 1 second, the value of counter C becomes zero. If the throttle valve is fully closed at Lost Step 7'2011C, In step 209, it is determined whether 2.5 seconds have elapsed since the throttle was fully closed. If 2.5 seconds have not elapsed since the throttle was fully closed, it is determined in step 210 whether or not the value of the load determination counter C is zero. cNo means that the Q/N exceeded 0.3 l/rev within 1 second before the throttle valve was fully closed (there was a medium load condition), and 2 after the throttle valve was fully closed. This means that 5 seconds have not passed. This is the case when a Dalasi pot operation must be carried out to increase the amount of intake air. Therefore, cN.

In this case, in step 211, the increase correction term DsP for the dashpot function is set to 4.

Conversely, in step 210, being c-o means that Q/N is 06 within 1 second before the throttle valve is fully closed.
This means that it has never exceeded 31/rev (there has been no medium load state). In this case, there is no risk of engine stalling even if the intake amount is not increased, so step 2
11 and proceeds to step 205.

If 2.5 seconds have passed since the throttle was fully closed in the Stella F201c, the possibility of engine stall has decreased. Therefore, in this case, the process proceeds to step 204, where 0.1 is decremented from the numerical value 4ch of the dash pit function increase correction term DsP previously set in step 211. As mentioned above, this duty ratio calculation routine is repeated every engine revolution, so step 20
If the engine rotates 40 times under the condition of proceeding from 9 to step 204, the value of DsP set for the 4th section in step 211 becomes zero. From the above, if the throttle valve is fully closed within 1 second from a medium load state, then 2.5
DBP is maintained at 4 for the second, and after 2.5 seconds, DBP is maintained at 4!
The value of IP attenuates with each engine revolution and becomes zero after 40 revolutions. As long as the DBP value is large, the dashpot effect can be obtained. Each of the above steps is substantially different from the conventional method.

Next, the Stella F205 determines whether the vehicle traveling speed is 10 km/h or more according to the present invention.

If the speed is 1 ob/h or more, the engine speed is high and the engine is rotationally driven by the drive system, so there is no risk of an engine storm. Therefore, preferably, in step 206, the dash board F function correction term D8P
Erase the value to zero. Note that step 206 does not necessarily have to be provided. Vehicle speed is 10k+++/
If it is more than h, the dashpot effect is required, so proceed to step 207.

The Stella f207 determines whether one second has elapsed since the throttle was fully closed. If it is before 1 second has elapsed, the vehicle speed is high, so it is desirable to ensure the engine braking effect. Therefore, the process proceeds to step 208, and the process proceeds to step 11.
Learning value updated with 0, and -dash? Using the correction term Dsp for the cut function, calculate D←Do+1)8P-5% to obtain the final duty ratio. put it here,
Since DsP is erased to zero in Stella 7t'' 206, the final duty ratio is actually D=D, -5ch, and therefore, D is the learned value of the basic duty ratio during feedback control. The value has been corrected by reducing the amount by 5 inches.In this way, the engine braking performance for 1 second after the throttle is fully closed is improved.

If it is determined in step 207 that one second has elapsed, the process advances to step 212 and D+-Do+Ds.

Let be the final duty ratio. In this case also step 20
6, Dsp is erased to zero, so the final duty ratio is actually D=D.

Therefore, if the vehicle speed is 10 km/h or more and 1 second has passed after the throttle is fully closed, the learned value of the basic duty ratio will be used. is used.

If the vehicle speed is 10 km/h or less in step 205, the process proceeds to step 212 and sets D(-Do+DIIP as the final duty ratio. In this case, DBP is also the value of the 4th coefficient set in step 211.
Since the final duty ratio has a value of 0 to 3.9t4 which is attenuated by 4, the final duty ratio is a value that can exhibit the dashpot function according to the value of DBP.

The final duty ratio thus obtained at Stella 7' 208 or 212 is transferred to the output register at Stella f112.

Final step 11 of the duty ratio calculation routine described above
The duty ratio value stored in the register of the MPU 70 in step 2 is then tJ? used to form a pulse signal.

That is, a clock signal is outputted to the register from the clock 76 every unit time, which is formed by dividing the pulse width of one cycle of the t4 pulse signal outputted from the register into a large number of parts, and the value of the duty ratio stored in the register is equal to the one described above. 0 is counted down every unit time.During this period, as long as the value in the register exists, the register outputs QN and f pulses, and when the register reaches zero, the 0N-4' pulse ends and one cycle of the pulse signal ends. . This)4 pulse signal is input to the drive circuit 92 via the output hoard 90, and the drive circuit amplifies the Nockles signal and sends it to l5CV50 in the form of a driving pulse current, thereby opening the l5Cv. Since the pulse current for
It will be controlled by 10FF.

As is clear from the above, in the intake air amount control device of the present invention, when the vehicle running speed is above a certain value, the basic control value is corrected by decreasing it over a certain period of time after the throttle valve is fully closed. Since this is provided, it is possible to sufficiently exert the engine braking effect while the vehicle is traveling at a speed higher than the predetermined value, and the fuel consumption rate can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a part of an engine engine equipped with the intake air amount control device of the present invention, Fig. 2 is a block diagram of the electronic control unit, Fig. 3 is a flowchart of the duty ratio calculation program, and Fig. 4 (,) and FIG. 4(b) show an example of a map of the correction part of the integral term and the proportional term of the duty ratio, and FIG. 5 is a flowchart of the decrement routine of the load discrimination counter C. 12...Intake pipe, 14...Surge tank, 30...
・Electronic control unit, 32...throttle valve\4
8... Idle speed control passage (Pinox for idle air), 50... Idle speed control valve (electromagnetic air control valve).

Claims (1)

[Claims] An on/off type electromagnetic air control valve is provided on a bypass that controls the throttle valve of an internal combustion engine, and adjusts the intake air flowing through the bypass according to the duty ratio of a Noyal signal, and basic control value setting means for setting a basic control value of a duty ratio of a master pulse signal; basic control value increase correction means for adding an increase correction value over time; and reduction correction means for reducing the basic control value over a second predetermined time period after the throttle valve is fully closed when the vehicle speed is equal to or higher than a set value. and,
An intake air amount control device for an internal combustion engine, comprising an output means for outputting a pulse signal having a duty ratio corresponding to a basic control value to which an increase correction value has been added or a reduction correction value has been added to an electromagnetic air control valve. .