JPH0364642A - Rotation frequency control device of engine - Google Patents

Abstract

PURPOSE:To prevent an abnormal reduction of the actual rotation frequency by controlling by the larger side value of the control amount of an air control valve in a bypass conduit pipe and a specific control amount, for a specific time after it becomes the first idle condition where the coolant temperature is less than a specific value, and after it becomes the second idle condition where the coolant temperature is at the specific value or higher. CONSTITUTION:In the first bypass conduit pipe 10 to bypass a throttle valve 7 in a suction pipe 3, an air control valve 11 to present the opening amount responding to the duty ratio of the driving signal is provided. And in the second bypass conduit pipe 12 to bypass the throttle valve 7, a wax type first idle air valve 13 to close perfectly when the coolant temperature is at a specific value or higher is provided. And, in a control unit 20, when it is detected that the condition is in a specific time after the first idle condition where the coolant temperature is less than the above specific value, and after the second idle condition where the coolant temperature is at the above specific value or higher, the larger side control amount is selected from the control amount of the air control valve 11 and a preset specific control amount, and the air control valve 11 is controlled thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine rotation speed control device, and particularly to control of the rotation speed during fast idle control.

[Conventional technology]

Generally, the amount of fuel supplied is determined by the amount of air supplied to the engine, so it is known that the engine rotational speed can be controlled by controlling the amount of air supplied.

Conventional engine speed control devices use fast idle air pulp (FI), whose opening changes in inverse proportion to the cooling water temperature, during fast idle control until the engine warms up.
The amount of FIAV bypass air that passes through the FIAV bypass air (AV), and the idle speed control air il that passes through the air control valve that is controlled to a certain opening (the amount of rotational speed feed bank correction according to the deviation between the actual rotational speed and the target rotational speed) The rotation speed of the engine is controlled by supplying the larger of the predetermined correction amounts (the larger of the predetermined correction amounts to the basic air amount) to the engine. During idle control after warm-up, this device controls the opening degree of the air control valve by feedback control of the idle rotation speed so that the actual rotation speed converges to the target rotation speed.

[Problem to be solved by the invention]

The conventional engine speed control device is as described above.
Normally, as the fast idle air valve closes, the actual rotation speed approaches the target rotation speed, but there may be a discrepancy in the cooling water temperature due to a misalignment between the position where the engine cooling water temperature is detected and the fast idle air valve, or when the outside temperature is low and the engine starts warming up. Due to reasons such as low engine cooling water temperature or delayed temperature response of the fast idle air valve, feedback control of the idle speed may start immediately after warm-up even though the fast idle air valve is open. In this case, depending on the conditions, the feedback correction acts to reduce the idle speed control air amount and also reduces the FIAV bypass air amount, resulting in insufficient air supply, and the actual rotation speed may be significantly lower than the target rotation speed. There were problems such as a decrease in engine speed and, in the worst case, an engine stall.

The present invention has been made to solve the above-mentioned problems, and it prevents an abnormal drop in the actual rotation speed by continuing fast idle control for a predetermined time even if the coolant temperature reaches a predetermined temperature. The purpose is to obtain an engine speed control device that can control the engine speed.

[Means to solve the problem]

The engine rotation speed control device of the present invention includes an air control valve;
A first idle state in which the coolant temperature is less than the predetermined temperature in an apparatus including a valve means that is fully closed at a temperature near a predetermined temperature and a control means that controls an air control valve to perform feedbank control of the idle rotation speed. , a detection means for detecting that a second idle state in which the temperature is higher than a predetermined temperature is reached within a predetermined time; is used selectively.

[For production]

In the engine speed control device of the present invention, the valve means may not be fully closed but open when the first idle state shifts to the second idle state. means is fully closed, and the control means extends the fast idle control for a predetermined period of time to control the air control valve '4'.
nI is clamped to a minimum predetermined control amount, and after the valve means is fully closed, feedbank control of the rotational speed is performed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a configuration diagram showing an engine rotation speed control device etc. according to an embodiment of the present invention. In the figure, reference numeral 1 is a spark ignition type engine installed in, for example, a car, which inhales main air through an air cleaner 2, an intake pipe 3, and an intake branch pipe 4. type fuel injection valve 5
It is supplied by injection from a single unit. This fuel amount is, for example, the intake pipe 3
This is determined by a fuel control system (which may be an electronic control unit 20, which will be described later, but is not shown) based on the output signal of the pressure sensor 6 that detects the internal pressure as an absolute pressure.

7 is a throttle valve that adjusts the main intake air amount of the engine 1 by the driver's arbitrary operation of the accelerator pedal (not shown), 8 is a throttle opening sensor that detects the opening of the throttle valve 7, and 9 is a throttle valve. 7 is fully closed, and turns on when detected.

10 is a first bypass conduit that bypasses the throttle valve 7 on the downstream side of the fuel injection valve 5; 11 is an air control valve that is provided between the first bypass conduits 10 and controls the cross-sectional area of the flow path; An electromagnetic control valve is used whose opening degree corresponds to the duty ratio of the signal. 12 is a second bypass conduit that bypasses the throttle valve 7; 13 is a well-known wax-type fast pipe that is provided between the second bypass conduits 12 and controls its flow passage cross-sectional area according to the cooling water temperature of the engine 1; With idle air pulp, when engine 1 warms up, it becomes fully closed.

1st. Each one end of the second bypass conduit 10.12 is connected to each air inlet of the intake pipe 3 section provided between the fuel injection valve 5 and the throttle valve 7; The other ends of the second bypass conduits 10.12 are commonly connected to the air outlet of the intake pipe 3 section provided downstream of the throat valve 7.

The ignition system of the engine 1 is connected to an ignition control system (which may be an electronic control unit 20, but not shown) that forms an ignition signal from engine operating state parameters, and in response to this ignition signal, the primary An igniter 15, an ignition coil 14, a distributor (not shown), and a spark plug (not shown) for controlling on/off of the 11 m.
It is composed of etc.

16 is a cooling water temperature sensor that detects the temperature of the engine 1, for example, a cooling water temperature sensor; 17 is an electric load switch for turning on a load such as an air conditioner; 1 is a neutral switch that generates a torque converter signal for the automatic transmission; 19
is a vehicle speed sensor that detects vehicle speed by outputting a pulse signal with a frequency proportional to the rotational speed of the axle.

Reference numeral 20 denotes an electronic control unit that is operated by being supplied with power from a battery 21 via a key switch 22, which detects idle/non-idle states from each output signal from an idle switch 9 and a vehicle speed sensor 19, and when idle, the ignition coil is activated. 14, the signal from the cooling water temperature sensor 16, each signal from the electric load switch 17 and the neutral switch 18, etc. to determine the control amount of the air control valve 11, or when the air control valve 11 is not idling. The control amount during open loop control is determined and the air control valve 11 is driven and controlled.

Next, the electronic control unit 20 will be explained with reference to FIG. 100 is a microcomputer that calculates idle rotation control amounts, etc. according to a predetermined program.
PU 200, a free running counter 201 for measuring the rotation period of the engine 1; a multi-configuration timer 202 for measuring time every 100 days and the duty ratio of the drive signal applied to the air control valve 11; an analog input signal An A/D converter 203 that converts the signal into a digital signal, an input port 204 that inputs the digital signal as it is,
RAM 205 as a work memory, ROM 206 that stores programs such as the flowchart in Figure 3.
, an output boat 207 for outputting drive signals, a common bus 208, and the like. 101 is a first human powered ink face circuit which shapes the waveform of the primary side ignition signal of the ignition coil 14 and outputs it to the microcomputer 100 as an interrupt signal. When this interrupt signal occurs, the CPU
200 reads the value of the counter 201, calculates the cycle of the engine rotation speed from the difference from the previous value, and stores it in the RAM 205. A second manual ink face circuit 102 removes noise components from the output signal of the cooling water temperature sensor I6 and outputs the output signal to the A/D converter 203. 1
Reference numeral 03 denotes a third human power interface circuit, which controls the on signals of the idle switch 9 and the electric load switch 1, the neutral safety signal when turned on from the neutral switch 18, and the pulse signal from the vehicle speed sensor 19 to predetermined levels, and controls the human power boat 204. Output to. 104 is an output interface circuit which amplifies the drive signal from the output port 207 and outputs it to the air control valve 11. Reference numeral 105 denotes a power supply circuit which maintains the voltage from the battery 21 at a constant voltage when the key switch 22 is turned on. l
supply power.

Next, the operation of this embodiment will be described with reference mainly to FIG. 3 among FIGS. 1 to 3. First, in step S1, it is determined whether the throttle valve 7 is fully closed, the idle switch 9 is turned on, the vehicle is stopped, and the vehicle speed sensor 19 is in an idle state in which no pulse is generated within a predetermined time. Proceed to S2, ignition coil 14
The actual rotation speed Ne is calculated based on the rotation period detected from the ignition signal on the primary side of the engine. In step S3, engine 1
The target rotational speed Nt, which is independent of the cooling water temperature, is calculated according to the operating state of the engine, for example, whether the electric load switch 17 is on or off, whether the neutral switch 18 is on or off, that is, whether the automatic transmission is in the neutral range or the drive range. In the next step S4, a basic air amount QiAsi that is unrelated to the cooling water temperature is calculated according to the operating state of the engine 1. This basic air amount QIIAsE is for maintaining the target rotational speed Nt. In step S5, it is determined whether the timing is every 100 μs or not, and if the timing is not the timing, the process jumps to step S14, and if the timing is the timing, the process proceeds to step S6. In step S6, the target rotation speed Nt and the actual rotation speed Nt
Using the ΔN map shown in FIG. 4 from the deviation ΔN of e, + is calculated for the control gain Δ corresponding to the deviation ΔN. Next, in step S7, the rotation speed feedback correction 1tQ, which was obtained last time 100 m5 ago, is calculated. , and the control gain ΔKl is added to obtain a provisional rotation speed feedback correction amount Q vya'. In the next step S8, the cooling water temperature sensor 16 is connected to the second human interface circuit 102 and the A/D converter 20.
Cooling water temperature (direct WT) representing the cooling water temperature read through 3
FIA assumed that Fast Idle Air Pal would close
It is determined whether or not the set water temperature value for V fully closed determination is equal to or higher than WTr+Av. In reality, the fast idle air valve 13 is fully closed at a water lA value close to this set water temperature value for FIAVI close determination. If it is not greater than but less than, the process proceeds to step S9, where a timer (in this embodiment, a soft timer) is set to an initial value for the predetermined time To, and then the process proceeds to step 310, where a provisional rotation speed feedback correction amount Q. r. ' and a predetermined set air amount Q□8, and select the larger one as the rotation speed feedback correction amount Q. ,.

Close and set.

On the other hand, if it is determined in step S8 that the cooling water temperature value WT is equal to or higher than the set water temperature value W T F I A V for FIAV fully closed determination, the process proceeds to step 311 and the above-mentioned timer value is set to 1.
After decrementing by 1, for example, by 00ms (limited to 0), the process proceeds to step S12. Step S1
2, whether or not the timer value is 0, that is, WT
It is determined whether a predetermined time T0 has elapsed since ≧WTFIAV, and if the above-mentioned timer value is 0, step 31
If the timer value is 0 and the predetermined time T0 has elapsed, the process advances to step 513. In step 513, the temporary rotational speed feedback correction 1tQ□1 is set to the rotational speed feedbank correction amount QN,ll.

After the processing of step S1O or S13, or step S
After determining that it is not the timing in step 5, step S1
Proceed to step 4. In step S14, the basic air amount QIA3E
and the rotational speed feedback correction amount Qsrs to obtain the idle speed control air IQ. ．． Find c. Step S
In step 15, the duty ratio is calculated using the idle speed control air IQ,,c using the Q+sc manbu shown in FIG. As shown in FIG. 6, this duty ratio is determined by setting the period of the drive signal for driving the air control valve 11 to be T, and the on-time period during one period to be T. N, it is given by ON TXloo [21. Next step S
16 outputs a drive signal corresponding to the duty ratio to the boat 207.
and the air control valve 1 via the output ink face circuit 104
1 and drive and control it.

On the other hand, if it is determined in step S1 that the idle switch 9 is off or that the vehicle speed sensor 19 is in a non-idling state where it is generating pulses, the process advances to step S17, and the air I QOPEN, which is the value at which oven loop control is entered, is determined. The idle speed control air fiQ. ．． .

Set as . After processing step 317, step 5
Proceed to step 15 and perform the same operation as above.

Note that after the process of step S16, the process returns, but after returning, other main routine processes (fuel supply control,
After performing ignition timing control), the process returns to step S1 and repeats the above operation.

Figure 7 shows the actual rotational speed Ne and cooling water'/
H Ia W T, FIAV bypass air amount Qr+av passing through the fast idle air valve 13, rotation speed feedback correction fftQ. □ It shows the change in idle speed control air 'JQ+sc over time t. Until the time of warming up, the cooling water temperature value WT rises, and accordingly, the FIAV bypass air II Q F I A V
decreases because the fast idle air valve 13 gradually closes. In response to this decrease in the amount of air, the actual rotational speed Ne approaches the target rotational speed Nt. At time 1, WT=WT Due to the deviation, the fast idle air valve 13 is still open and supplies a large amount of FIAV bypass air QFIAV to the engine. However, in this embodiment, feedback control of idle rotation is started after time To has elapsed from time Ll, and during this time period (from time L1 to tz), fast idle control is continued and the provisional rotation speed feedbank correction amount is The larger one of Q8□" and set air IQ,... is used as the rotation speed feedback correction ff1Q, □. Until time t2 when the predetermined time T0 has elapsed, the actual rotation speed Ne exceeds the target rotation speed NL. Therefore, the idle speed control air amount Q, , rotation speed feedback correction ffQ
, , are clipped to the set air amount QIH. As a result, the actual rotational speed Ne gradually decreases and approaches the target rotational speed. During this period (time t, ~tz), the fast idle air valve 13 is fully closed and the FTAV bypass air ME
Q r l AV becomes 0. In this state, and in a state where the actual rotational speed Ne approaches the target rotational speed Nt, the feedback control of the idle rotational speed is started from time t2, so that the actual rotational speed Ne smoothly converges to the target rotational speed Nt.

Conventionally, feedback control of the idle rotation speed is started from a state where the fast idle air valve is open at time t and the actual rotation speed Ne is larger than the target rotation speed Nt to some extent, as shown by the dashed line. For this reason, immediately after time t1, the rotation speed feedback correction f
As f1Qsyll rapidly decreases from Q M +, FIAV bypass air IQF1Av also decreases. Due to this double reduction in the air supply amount, the actual rotational speed Ne temporarily becomes significantly lower than the target rotational speed NL.

As shown by the broken line Q r ln v, when the temperature at the start of warm-up is relatively high, W T -W T -lA
Since the fast idle air valve is fully closed before the time t+, which becomes v, and the feedback control is started after this complete closing, there is no problem in either the present embodiment or the conventional example.

In the waveform diagram in Figure 7, QNFI is input to Q until time 1z.
However, the actual rotation speed Ne decreased quickly at time t2.
If Ne is previously below Nt, the period QNFI' becomes larger than Q□8 and is used as Q,□. As a result, at time t2, the actual rotational speed Ne is approximately equal to the target rotational speed Nt.

FIG. 8 shows another embodiment of the present invention, in which step S9 in FIG. 3 is deleted as shown in FIG. 8(a), and step S1 is changed as shown in FIG. Same as S
The third point is that steps S20 and 321 are provided between
Unlike the process shown in the figure, other aspects are the same. Step S1
If it is determined that the idle state is reached, the process proceeds to step S20, and the cooling water temperature WT is set to the set water temperature value W for FIAV fully closed determination.
It is determined whether the value is greater than or equal to T F I s v. If not, an initial value of 70 minutes for a predetermined time is set in the timer in step 321, and after the clock is set, the process moves to step S2, and the WT
If it is ≧WTrIAV, the process proceeds to step S2. Other processing is the same as in FIG. 3, so its explanation will be omitted.

Note that in step S8, the cooling water temperature (IWT may be newly read and compared with WT and AV, but in step S20
The results of the comparison may be determined by flag identification.

(Effects of the Invention) As described above, according to the present invention, the predetermined coolant temperature is determined so that the valve means is fully closed at a temperature close to the predetermined temperature, and the first idle state,
Within a predetermined period of time after entering the second idle state where the temperature is higher than the predetermined temperature, the control amount of the air control valve and the predetermined limit are adjusted by feedback control of the rotation speed. Since the larger one of 1 N is selectively used and the rotational speed is then subjected to feedbank control, it is possible to prevent an abnormal decrease in the actual rotational speed.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an apparatus, etc. according to an embodiment of the present invention, and FIG.
The figure is a block diagram showing the configuration of the electronic control device etc. in Fig. 1, Fig. 3 is a flow diagram showing the flow of operation according to an embodiment of the present invention, and Fig. 4 is the rotation speed deviation ΔN and control gain ΔKT.
A diagram showing the relationship between the idle speed control air f and FIG.
A diagram showing the relationship between f1Q,,c and the duty ratio, FIG. 6 is an explanatory diagram for explaining the duty ratio of the drive signal, and FIG. 7 is an illustration for explaining the operation according to an embodiment of the present invention. FIG. 8 is a partial flow diagram showing a modified part of the operation according to another embodiment of the present invention. In the figure, l... Engine, 3... Intake pipe, 5... Electromagnetic fuel injection valve, 6... Pressure sensor, 7... Throntle valve, 9... Idle switch, 10... ... first bypass conduit, 11 ... air control valve, 12 ... second
Bypass conduit, 13...Fast idle air valve, 14...Ignition coil, 16...Cooling water temperature sensor, 19...Vehicle speed sensor, 20...Electronic control unit, 21...Battery. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] An air control valve is provided in a first bypass passage that bypasses the throttle valve of the engine, and an air control valve is provided in a second bypass passage that bypasses the throttle valve, and the air control valve opens and closes depending on the temperature of the coolant of the engine and maintains a predetermined temperature. and a valve means that fully closes at a temperature higher than or equal to a temperature in the vicinity of A first idle state in which the coolant temperature is lower than the predetermined temperature based on the operating state parameters of the engine; , further comprising a detection means for detecting that the coolant temperature is within a predetermined time after the coolant temperature reaches the second idle state equal to or higher than the predetermined temperature, and the control means receives a detection signal from the detection means, An engine rotation speed control device characterized in that the larger one of the control amount of the air control valve and a predetermined control amount is selectively used.