KR930006055B1 - Idle control apparatus of engine - Google Patents

Abstract

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Description

Idle control of engine

1 is a block diagram of the entire apparatus according to the first embodiment of the present invention.

2 is a block diagram of a control device and the like in the first diagram.

3A and 3B are flowcharts showing CPU operation in the control device.

4 is a graph showing an atmospheric pressure detection region.

5 is a graph showing the pressure loss of the intake system with respect to engine speed as a parameter of throttle opening.

* Explanation of symbols for the main parts of the drawings

1: engine 2: intake manifold

3: intake pipe main body 4: air cleaner

5: injector 6: throttle valve

7: Bypass barrel 10: Throttle opening degree sensor

12: exhaust teaware 13: air-fuel ratio sensor

16: igniter 100: microcomputer

101,102: first and second input interface circuit 104: output interface circuit

105,106: first and second power supply circuits

The present invention relates to an engine idle control device for detecting the atmospheric pressure to control the opening and closing of the bypass passage bypassing the throttle valve.

Conventionally, this type of device is provided with an atmospheric pressure sensor separate from a pressure sensor that detects the intake manifold pressure of the downstream intake passage as an absolute pressure in the bypass passage bypassing the throttle valve. The opening and closing of the bypass passage was controlled in the idle state of the engine in accordance with the detected atmospheric pressure state.

Since the idle control device of the conventional engine is configured as described above, since an expensive atmospheric pressure sensor is provided separately from the pressure sensor, the device itself becomes expensive.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an idle control device for an engine that can control the opening and closing of the bypass passage in an idle state without using an atmospheric pressure sensor.

Moreover, the idle control apparatus of the engine which concerns on this invention is an opening / closing means which opens and closes a throttle opening degree sensor and a bypass passage, a pressure sensor which detects intake manifold pressure as absolute pressure, a rotation speed detection means, a throttle opening degree, and an engine In-area detection means for detecting that the rotation speed is greater than or equal to a predetermined time in the atmospheric pressure detection region, computing means for calculating a atmospheric pressure detection value by adding a set value to a pressure signal at the time of detection, and opening / closing according to a comparison result of the atmospheric pressure detection value and a predetermined value A control means for controlling the opening and closing of the means is provided.

The idle control apparatus of the engine according to the present invention detects the pressure by a pressure sensor and corrects the pressure signal as a set value by the calculation means since the intake manifold pressure is stable below a predetermined pressure loss when the detection means in the area detects it. The atmospheric pressure detection value is calculated, and the opening and closing of the bypass passage is executed by the control means at the time of idling according to the comparison result of the atmospheric pressure detection value and the predetermined value.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 shows an embodiment of the present invention, in which 1 is a well-known engine mounted on a vehicle, for example, 2 is an intake manifold of the engine 1, 3 is connected to an upstream port of the intake manifold 2, The intake pipe main body constituting the intake pipe as the intake manifold 2, 4 is an air cleaner installed at the inlet of the intake pipe main body 3, 5 is to inject fuel into the intake pipe main body 3 to supply the engine 1 It is an injector. 6 is a throttle valve installed in the intake pipe main body 3 to regulate the degree of intake air to the engine 1 by adjusting a degree of opening of the intake passage, and 7 is a throttle of the intake pipe main body 3. Bypass passages connected upstream and downstream of the valve 6 and bypassing the throttle valve 6, 8 are provided in the bypass passage 7 and the solenoid valve 9 opens and closes the bypass passage 7, It is a pressure sensor attached to the intake pipe main body 3 on the downstream side in the passage passage 7, detecting the intake manifold pressure P therein as an absolute pressure, and outputting a pressure signal having a magnitude corresponding to the detection output. 10 moves with the throttle valve 6, and outputs an analog voltage according to the opening degree of the throttle valve 6, for example, a potentiometer type throttle opening sensor, 11 is the coolant temperature WT of the engine 1 A coolant temperature sensor for detecting the temperature, 12 is an exhaust manifold of the engine 1, 13 is an air-fuel ratio sensor for detecting the oxygen concentration of the exhaust gas in the exhaust manifold 12, 14 is a three-way catalyst for purifying exhaust gas Is a converter. 15 is an ignition coil for supplying a high voltage to an ignition plug (not shown) of the engine 1, 16 is a collector of a switch transistor star is connected to the primary coil end of the ignition coil 15, and the ignition coil 15 It is an igniter to turn ON and OFF. Reference numeral 17 denotes a control device, which inputs various parameters of the engine 1, performs various kinds of discrimination, calculation, etc. using the data stored in advance, and controls the injector 5, the solenoid valve 8, and the like.

Next, with reference to FIG. 2, FIG. 3A, FIG. 3B, the internal structure of the said control apparatus 17 etc. is demonstrated in detail. In FIG. 8, 100 is a microcomputer, a CPU200 executing the flow shown in FIGS. 3A and 3B, a counter 201 functioning as a timer, a timer 202 for measuring the rotation period of the engine 1, and an analog A / D converter 203 for converting a signal into a digital signal, an input port 204 for inputting and transmitting a digital signal, a nonvolatile RAM 205 serving as a work memory, and the like shown in FIGS. 9A and 9B. ROM 206, which stores the flow shown in the program and stores data for comparison determination and calculation, an output port 207 for outputting the calculated fuel injection amount and solenoid valve 8, and the It is comprised in the common bus 208 etc. which connect each component in common.

101 is a first input interface circuit connected to the connection portion between the ignition coil 15 and the igniter 16, for inputting an ignition signal for detecting the engine speed N _E to the timer 202, and 102 a pressure sensor ( 9), a second input interface circuit for sequentially introducing analog output signals from the throttle opening sensor 10, the coolant temperature sensor 11, and the air-fuel ratio sensor 13 into the A / D converter 203, (103) Is a third input interface circuit for inputting other various signals. 104 is connected between the output port 207 and the injector 5 or the solenoid valve 8, the output signal from the microcomputer 100 as an injector (a pulse of a width corresponding to the fuel injection amount or an on / off signal). 5) and the output interface circuit 105 outputted to the solenoid valve 8 are connected to the + side of the battery 18 grounded at the − side via a key switch 19 to supply power to the microcomputer 100. The first power supply circuit 106 is a second power supply circuit that is always connected to the + side of the battery 18 and continues to supply power to the RAM 205.

4, the horizontal axis represents the engine speed N _E , the vertical axis represents the throttle opening degree θ, and indicates the range of the atmospheric pressure detection region as an oblique portion. The lower limit value θ _A (N _E) of the atmospheric pressure detection zone is the revolution number of the engine appears as the throttle opening degree value of θ corresponding to the N _E, and a larger value as the engine speed N _E is increased, corresponding to the engine revolution number N _E The throttle opening degree value is stored in the form of a map in the ROM 206 in advance. This atmospheric pressure detection region is located between 80 ° and the lower limit θ _A (N _E ) of the atmospheric pressure detection region, and the pressure loss in the intake passage downstream from the bypass passage 7 is 5 degrees. ? P _A (for example,? P _A is 30 mmHg) or less shown in FIG.

5, the horizontal axis represents the engine speed N _E , the vertical axis represents the pressure loss ΔP _B of the intake system, and when the pressure loss P _B is 0, the intake manifold pressure P becomes equal to atmospheric pressure. When the throttle opening degree θ is at the lower limit value θ _A (N _E ) of the atmospheric pressure detection region, it becomes constant as the pressure loss ΔP _B = ΔP _A as shown by the straight line L ₁ . DELTA P _A becomes DELTA P _A x 1/2, which is a set value for correcting the pressure loss of the intake passage downstream from the bypass passage 7 and is stored in the ROM 206 in advance. When the throttle opening degree θ is completely open, as shown by the curve L ₂ , the pressure loss ΔP _A increases with the increase of the engine speed N _E at a value close to zero, and approaches the pressure loss ΔP _A. When the throttle valve is opened to correspond to the engine speed in the atmospheric pressure detection region, the pressure loss is in the region between the straight line L ₁ and the curve L ₂ .

Next, the operation will be described. The outside air passes through the intake pipe main body 3 and the intake manifold 2 in an amount according to the opening degree of the throttle valve 6 together with the fuel injected by the injector 5 from the air cleaner 4. Inhaled by 1). In addition, when the solenoid valve 8 is on, the bypass passage 7 is opened, and air or the like is sucked into the engine 1 through the bypass passage 7. After intake, each well-known process of the engine 1 is performed. At the time of ignition, the igniter 16 is controlled from ON to OFF, and the ignition coil 15 supplies high voltage to an ignition plug (not shown) of the engine 1 to perform ignition. In addition, the exhaust gas is cured by the three-way catalytic converter 14 through the exhaust manifold 12 and discharged to the outside. The above operation is repeatedly executed to rotate the engine 1.

Next, an operation of executing the CPU 200 in the microcomputer 100 inside the control device 17 will be described. First, when the key switch 19 is turned on, a voltage is applied from the battery 18 to the first power supply circuit 105. The first power supply circuit 105 applies a constant voltage to the microcomputer 100. As a result, the operation of the controller 17 is started. Initially, initial setting is made at the start of operation, and for example, the value of the counter 201 as the timer TM is reset to zero. The interruption is interrupted every predetermined time by the start of the operation, and the flow of the interrupt routine shown in FIGS. 3A and 3B is repeatedly executed.

First, the engine speed N _E is calculated and stored in the RAM 205 based on the measurement data of the timer 202 which measures the rotation period of the engine 1 in step 301. The timer 202 also inputs an ignition signal generated when the igniter 16 changes from on to off from the igniter 16 via the first input interface circuit 101 (m-1) during ignition times. We measure time until m ignition. This measurement data is stored in the RAM 205 as another routine. Next, in step 302, a pressure signal indicating the intake manifold pressure P at the pressure sensor 9 and a throttle opening degree signal indicating the throttle opening θ at the throttle opening degree sensor 10 are input to the second input interface circuit 102. And are sequentially stored independently in the RAM 205 via the A / D converter 203. Next, in step 303, the volume efficiency C _EV of the engine 1 determined by the intake manifold pressure P and the engine speed N _E is calculated. Next, in step 304, the basic pulse width T _PWO of the fuel injection amount is calculated by a calculation formula of T _PWO = K (coefficient) x P x C _EV .

Next, in step 305, it is determined whether the output condition of the air-fuel ratio sensor 13 is active or not (or the detected temperature level of the coolant temperature sensor 11, etc.) or not, and the feedback condition of the air-fuel ratio is satisfied. In step 306, the feedback correction term C _FB of the fuel injection time is calculated by proportional integration control in accordance with the output of the air-fuel ratio sensor 13, and when the feedback condition is not satisfied, the correction term C _{FB is set} to 1 in step 307. Set to. The process proceeds to the step 308 after the processing of the step 306 or the step 307, and the pulse width T _PW of the fuel injection amount is calculated according to the calculation formula of T _PW = T _PWO x C _FB and stored in the RAM 205. . Next, the process proceeds to step 309, and the atmospheric pressure read from the ROM 206 in correspondence with the engine speed N _E of the rotation speed signal read by the throttle opening degree θ indicated by the throttle opening degree signal read from the RAM 205. Whether the detected throttle opening degree θ and the engine speed N _E are within the atmospheric pressure detection area in the oblique part of FIG. 4 is determined whether or not the lower limit value θ _A (N _E ) of the detection area is greater than or equal to. If out of the atmospheric pressure detection region at θ < θ _A (N _E ) as step 309, the counter 201 value, that is, timer TM is reset to 0 as step 310, and atmospheric pressure as θ ≥ θ _A (N _E ). If it is in a detection area, it will progress to step 311.

In step 311, the counter 201 value, i.e., the timer TM is counted up, and then, the flow proceeds to step 312, and it is determined whether or not the timer TM is equal to or greater than the predetermined value TMo, 313), the atmospheric pressure detection value indicating the atmospheric pressure P _A by the calculation is calculated according to the formula of P _A = P + DELTA P _A x 1/2. Here, a value indicating the intake manifold P is read from the RAM 205 and a value equivalent to DELTA P _A x 1/2 is read from the ROM 206.

After the processing of step 310, when it is determined in the step 312 that TM <TMo is less than a predetermined value, and after the processing of the step 313, the process proceeds to step 314. Whether or not the atmospheric pressure P _A according to the operation in step 314 is less than the predetermined pressure P _A6 i.e. to determine the atmospheric pressure P _A represents the atmospheric pressure by the operation detection value or not less than a predetermined set value of. If it is determined in step 314 that less than P _A <P _A0 , the air density of the atmosphere is lean, and as step 315, the solenoid valve 8 is controlled to be turned on via the output port 207 and the output interface circuit 104. When the bypass passage 7 is opened and P _A ≥ P _A0 is reached, the air density in the atmosphere is sufficient, and the solenoid valve 8 is controlled to be OFF in the same manner as the step 316 as described above in the bypass passage 7. To close it. After the processing of step 315 or 316, the process proceeds to the next step.

In this embodiment the opening and closing of the bypass passage 7 is particularly effective in the idling state of the engine 1 and the throttle valve 6 is set at the idling opening degree in idling, with respect to the solenoid valve according to the state of atmospheric pressure. By 8, the bypass passage 7 is opened and closed.

In the above embodiment, the lower limit value θ _A (N _E ) of the atmospheric pressure detection region may be used as a predetermined step of the engine speed N _E , may be obtained by watering calculation, and the lower limit value ΔP _A of the pressure loss is constant. It may be changed in response to the N _E.

As described above, according to the present invention, when the engine speed and the throttle opening degree are within a predetermined atmospheric pressure detection range, the atmospheric pressure detection value is calculated by adding a set value to a pressure signal from a pressure sensor that detects the intake manifold pressure. It is configured to control the opening and closing of the bypass passage bypassing the throttle valve depending on whether or not the detected value is less than a predetermined value, so that an inexpensive configuration can be obtained.

Claims (1)

The throttle opening degree sensor 5a which detects the opening degree of the throttle valve which limits the amount of main air intake to the engine, the opening-closing means 8 which opens and closes the bypass passage which bypasses the throttle valve, and the said bypass passage Pressure sensor 9 for detecting the intake manifold pressure of the intake passage on the downstream side with absolute pressure, rotation speed detection means 15 and 16 for detecting the rotation speed of the engine, and throttle opening in the throttle opening sensor In-region detection means for inputting a degree signal and a rotational speed signal from the rotational speed detection means and detecting that the pressure signal is longer than or equal to a predetermined time in an atmospheric pressure detection region where the pressure loss in the intake passage becomes less than or equal to a predetermined value ( 312) and arithmetic means 313 which receives the detection signal of the detection means in the area, adds a set value to the pressure signal in the said pressure sensor, and calculates an atmospheric pressure detector; In response to the comparison result of the atmospheric pressure detection value previously set predetermined value preset idling control apparatus of an engine provided with a control means (314, 315, 316) for controlling the opening and closing of the closing means.