JPH0968088A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain highly accurate optimal control by switching/communicating a pressure sensor to/with either one of an intake pipe and opening to the atmosphere through a three-way solenoid valve, and setting an operation condition on the basis of a measured value by the pressure sensor and an operation parameter. SOLUTION: After a power source is closed and is initially set, information from respective sensors except a pressure sensor 7 is read in, and is stored in a RAM 22. Next, whether or not an electric current is carried to a three-way solenoid valve 6 is judged, and when an electric current is not carried, detecting data of the pressure sensor 7 is stored in the RAM 22 as data of intake air pressure, and when an electric current is carried, the detecting data is stored in the RAM 22 as atmospheric pressure data. A fuel injection quantity and opening of an idle control valve are calculated on the basis of measured data from the respective sensors stored in the RAM 22. Next, this calculated calculation value is corrected by the atmospheric pressure data, and control signals of a fuel injector 12 and the idle control valve are outputted by this corrected calculation value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to an intake pipe pressure and atmospheric pressure measuring means for setting operating conditions.

[0002]

2. Description of the Related Art Conventionally, there is known a control device for an internal combustion engine of a speed density control system (SD system) which estimates a load from an intake pipe pressure and an engine speed and controls an injection amount of a fuel injection device. There is. In order to control the injection amount and the like of the fuel injection device by the SD method, it is necessary to measure the intake pipe pressure, the atmospheric pressure, and the engine speed. Therefore, two pressure sensors, one for measuring the intake pipe and one for measuring atmospheric pressure, have been used.

Thus, when two pressure sensors are used,
There is a problem that the error of each sensor is accumulated, the error of the air flow rate obtained from the measured value becomes large, and the pressure sensor is expensive, so that the manufacturing cost becomes high. In order to solve this problem, the pressure detecting device proposed in Japanese Patent Laid-Open No. Sho 60-98329 uses a pressure sensor connected to the intake pipe to throttle the engine when the engine speed is below a certain value near the throttle valve fully open position. The atmospheric pressure data is obtained by correcting the data obtained by measuring the pressure in the intake pipe downstream of the valve.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No.
According to the pressure detection device proposed in Japanese Patent No. 98329,
For example, when moving from a highland to a lowland, the altitude changes and the atmospheric pressure also changes, but it is difficult to open the throttle valve due to the low load on the downhill, and the data of the changed atmospheric pressure cannot be obtained. was there.

The present invention has been made in view of the above points, and an object thereof is to obtain pressure data in the intake pipe and atmospheric pressure data with one pressure sensor, and further, When moving from highlands to lowlands,
An object of the present invention is to provide a control device for an internal combustion engine that can reliably obtain data of changed atmospheric pressure.

[0006]

In a control device for an internal combustion engine according to the present invention, a pressure sensor is switched to communicate with either an intake pipe or an atmosphere open via a three-way solenoid valve, and the intake pipe pressure by the pressure sensor is communicated. Also, the operating condition is set based on the measured value of the atmospheric pressure and the operating parameter of the internal combustion engine.

[0007] In the control device for an internal combustion engine,
The operation period of the engine is divided so that the first predetermined period and the second predetermined period are alternately continuous, the pressure sensor is communicated with the intake pipe in the first predetermined period, and the pressure sensor is operated in the second predetermined period. It communicates with the atmosphere.

In the above arrangement, the intake pipe internal pressure data obtained by measuring the pressure of the intake pipe when the pressure sensor is in communication with the intake pipe is used as control data and stored in the memory. Atmospheric pressure data obtained by measuring atmospheric pressure when the pressure sensor is open to the atmosphere is used as control data and is also stored in the memory. When the pressure sensor cannot measure the intake pipe internal pressure, the intake pipe internal pressure data required for control can be the data stored in the memory up to that point. The same applies to atmospheric pressure data. The first predetermined period may be set to a time at which a change in atmospheric pressure, which affects control, appears to some extent when the vehicle is moving in a place having a height difference. Further, the second predetermined period may be set to a time at which the pressure sensor portion is at atmospheric pressure when the three-way solenoid valve is switched from the state in which the pressure sensor is in communication with the intake pipe to the atmosphere.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A control device for an internal combustion engine to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is a block diagram showing a control device for an internal combustion engine to which the present invention is applied.
In the figure, reference numeral 1 denotes an internal combustion engine body, air is supplied to a cylinder 5 through a throttle body 2 and an intake pipe 4, and fuel is injected from a fuel injector 12. The amount of intake air is controlled by the throttle valve 3 which works in conjunction with the accelerator pedal. The fully closed state of the throttle valve 3 is detected by the throttle sensor 13. Further, when the throttle valve 3 is fully closed, the intake air amount is controlled by the idle control valve 10 arranged in the bypass passage.

The intake air temperature sensor 9 detects the temperature of the intake air in the intake pipe 4, and the water temperature sensor 11 detects the temperature of the cooling water.
The crank angle sensor 8 detects the rotation angle of the crank.
The pressure sensor 7 is open to the atmosphere when the three-way solenoid valve 6 is energized, and the intake pipe 4 is released when the three-way solenoid valve 6 is not energized.
Is communicated to.

Reference numeral 20 is a control circuit, which comprises a microcomputer 21, a RAM 22, a ROM 23 and an input / output interface 24. The control circuit 20 performs a calculation for controlling the engine to an optimum operating state based on the signals from the above-mentioned sensors, and the fuel injector 1
2 and control signals of the idle control valve 10 are output, and the three-way solenoid valve 6 is controlled.

Next, the operation of the control circuit 20 will be described with reference to FIGS. When the power is turned on, initialization is performed and then the routine shown in FIG. 2 is repeatedly executed. In this routine, in step S1, the information from each sensor other than the pressure sensor 7 is read and the RAM2 is read.
Store it in 2. Next, in step S2, it is determined whether or not the three-way solenoid valve is energized. When energized, the process proceeds to step S4, and when not energized, the process proceeds to step S3. In step S3, the detection data of the pressure sensor 7 is stored in the RAM 22 as intake pressure data, and the process proceeds to step S4.

In step S4, the fuel injection amount and the opening degree of the idle control valve are calculated based on the measurement data from the sensors stored in the RAM. Next, atmospheric pressure data Pat
The calculated value is corrected by a, and the process proceeds to step S6. In step S6, the control signals for the fuel injector 12 and the idle control valve are output based on the corrected calculated value, and this routine ends.

FIG. 3 is a routine for controlling the three-way solenoid valve, which is executed at regular intervals. When this routine is called, first, in step S10, the flag F
Is determined to be 0, and if F = 0, step S13.
If F = 0 is not satisfied, the process proceeds to step S11. In step S13, the flag F is set to 1, and then
In step S14, the first timer that counts the first predetermined period is started, and this routine ends.

In step S11, it is determined whether or not the flag F is 1, and when F = 1, the process proceeds to step S15.
When F = 1 is not satisfied, the process proceeds to step S12. In step S15, it is determined whether or not the first timer has counted up. If the first timer has not been counted up, this routine is ended, and if it is counted up, the process proceeds to step S16. Flag F in step S16
Is set to 2, then the process proceeds to step S17, the three-way solenoid valve is energized, and the first timer is reset in step S18, and the process proceeds to step S19. In step S19, a second timer that counts the second predetermined period is started, and this routine ends.

In step S12, it is determined whether or not the second timer has been counted up. If the second timer has not been counted up, this routine is ended, and if it is counted up, the process proceeds to step S20. In step S20, the detection data of the pressure sensor 7 is stored in the RAM 22 as atmospheric pressure data, and the process proceeds to step S21. In step S21, the second timer is reset, then in step S22, the energization of the three-way solenoid valve is stopped, and in step S23, the flag F is set to 0 and the routine is finished.

The count time of the first timer is set to a time at which the atmospheric pressure changes to a certain extent to affect the control when the vehicle is moving in a place having a height difference.
The second counting period is set to a time at which the pressure sensor portion is at atmospheric pressure when the three-way solenoid valve is switched from the state in which the pressure sensor communicates with the intake pipe to the atmosphere.

In the above control device, the average value of the measured values of the past n times or the weighted average value may be used as the data of the intake pressure or the atmospheric pressure. Further, the measurement value of the intake pressure may be obtained after a predetermined period of time after switching the pressure sensor of the three-way solenoid valve so as to communicate with the intake pipe.

[0019]

As described above, the control device for an internal combustion engine according to the present invention can obtain the pressure data in the intake pipe and the atmospheric pressure data with one pressure sensor, so that the manufacturing cost is reduced. Moreover, even when moving from a highland to a lowland, the data of the changed atmospheric pressure can be surely obtained, so that the optimum control of the internal combustion engine can be always executed. Further, since the common pressure sensor measures the atmospheric pressure and the intake pressure, the error of the pressure sensor does not accumulate, and since the atmospheric pressure is directly measured, accurate data can be obtained and highly accurate optimum control can be achieved. Can be executed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control device for an internal combustion engine to which the present invention is applied.

FIG. 2 is a flowchart showing an operation of the control device.

FIG. 3 is a flowchart showing an operation of the control device.

[Explanation of symbols]

 1 Internal combustion engine body 2 Throttle body 3 Throttle valve 4 Intake pipe 5 Cylinder 6 Three-way solenoid valve 7 Pressure sensor 8 Crank angle sensor 9 Intake temperature sensor 10 Idle control valve 11 Water temperature sensor 12 Fuel injector 13 Throttle sensor 20 Control circuit 21 Microcomputer 22 RAM 23 ROM 24 I / O interface

Claims (2)

[Claims] 1. A pressure sensor is connected to one of an intake pipe and an atmosphere open via a three-way solenoid valve for communication, and based on measured values of the intake pipe pressure and atmospheric pressure by the pressure sensor and operating parameters of an internal combustion engine. A control device for an internal combustion engine, which sets operating conditions. 2. The engine operating period is a first predetermined period and a second period.
2. The pressure sensor is communicated with the intake pipe during the first predetermined period, and the pressure sensor is communicated with the atmosphere during the second predetermined period. Control device for internal combustion engine.