JPS6139502B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas recirculation control device that recirculates a portion of exhaust gas to an intake pipe.

Currently, internal combustion engines are subject to ignition timing control, air-fuel ratio control, and exhaust gas recirculation control, as shown in Japanese Patent Application Laid-open No. 18531/1983.

Furthermore, it is necessary to further improve the accuracy of these controls.

The present invention particularly aims to improve the accuracy of exhaust gas recirculation control, and this purpose is to improve the accuracy of exhaust gas recirculation control, and this purpose is as follows: (a) air flow rate calibration detection means for detecting the amount of intake air of an internal combustion engine; rotation detection means for detecting the rotation speed of the engine; (c) control means for transmitting a control signal to the injection valve based on the intake air amount and rotation speed detected by both of the detection means; Pressure detection means for detecting the pressure of the intake pipe; (e) Exhaust gas recirculation passage that recirculates part of the exhaust gas to the intake pipe; (f) Exhaust gas recirculation adjustment means that adjusts the amount of exhaust gas flowing through the exhaust gas recirculation passage. (g) storage means comprising an electric memory for storing a predetermined set exhaust recirculation rate corresponding to the rotational speed of the internal combustion engine and the pressure of the intake pipe; (h) storage means consisting of an electric memory for storing a predetermined set exhaust recirculation rate corresponding to the rotational speed of the internal combustion engine _and the pressure of the intake pipe; Exhaust gas recirculation rate = (K・P _M −Q _a /N)/(K・P _M ) where _K is a constant. This is achieved by an exhaust gas recirculation control device comprising an exhaust gas recirculation control means that controls the exhaust gas recirculation amount adjusting means so that the recirculation rate is equal to the set exhaust gas recirculation rate stored in the storage means.

The details will be explained below with reference to the drawings.

FIG. 1 is a system diagram showing the main configuration of the engine control device. The amount of air taken in through the air cleaner 10 is measured by an air flow meter 12, and an electrical output Q _A correlated with the air flow rate is input from the air flow meter 12 to a control device 14 consisting of a microcomputer.

Furthermore, an intake air temperature sensor 16 is installed in the air flow path of the air flow meter 12 to eliminate the influence of temperature. Further, a pressure transducer 22 for detecting intake pressure is provided downstream of the throttle valve 20 in the intake pipe 18 , and the output of the pressure transducer 22 is guided to the control device 14 . moreover,
Exhaust gas recirculation passage 26 connecting exhaust pipe 24 and intake pipe 18
is equipped with an exhaust gas recirculation amount adjusting section consisting of a pulse solenoid valve 28 and a negative pressure control valve 30, and the pulse width to the pulse solenoid valve 28 is controlled by a command signal from the control device 14, and the pulse width is 40 Hz at maximum. Driven by frequency.

Further, a fuel injection valve 32 is provided downstream of the intake pipe 18, and this fuel injection valve 32 is connected to the control device 1.
It is controlled by the signal from 4. Further, the rotation speed is determined from the crank angle sensor 34.

Next, a specific control method will be described.

In the embodiment _shown in _{FIG .
Assuming} that _the air _{amount Q a measured at}
・R/T _a・P _M (1) The first term in equation (1) is the total amount of gas in the cylinder, and the second term is the amount of fresh air sucked into the cylinder.

Here, the items V _h , R, and T _a can basically be considered to have the same influence during control, so equation (1) is expressed as: Exhaust recirculation rate = (K・P _M −Q _a /N)/ (K P _M ) ...(1)' may also be used.

In order to set the exhaust recirculation rate to a predetermined value using equation (1) or (1)', the exhaust recirculation rate must be set in advance in the memory circuit of the control device 14 in accordance with the engine speed N and the intake pressure P _M. It is stored as a voltage value or digital amount corresponding to the rate. In reality, the operating conditions are determined by two variables, N and P _M , and the values of N and P _M at that time and the output from the air flow sensor 14 are substituted into equation (1) or (1)' to determine whether the exhaust gas is The value of the recirculation rate is calculated in the control device 14, and compared with the stored value of the set exhaust recirculation rate mentioned above, the pulsed electromagnetic pulse shown in FIG. The driving frequency of the valve 28 may be controlled. As can be seen from equations (1) and (1)', this method uses the value of the difference between the total amount of gas in the cylinder and the amount of fresh air, so the exhaust recirculation amount including the amount of residual gas in the cylinder is It has the desired advantages and also has the advantage of being able to absorb errors caused by wear over time of intake and exhaust valves, piston rings, etc. around the engine.

[Brief explanation of the drawing]

The drawing is a main configuration diagram of the engine control device. 12... Air flow sensor, 14... Control device, 22... Pressure detector, 28... Pulse solenoid valve.

Claims (1)

[Scope of Claims] 1 (a) Air flow rate detection means for detecting the intake air amount of the internal combustion engine; (b) Rotation detection means for detecting the rotational speed of the internal combustion engine; (c) Detection from both of the detection means; (d) pressure detection means for detecting the pressure of the intake pipe of the internal combustion engine; (e) a part of the exhaust gas is transferred to the intake air; (f) Exhaust gas recirculation amount adjusting means for adjusting the amount of exhaust gas flowing through the exhaust gas recirculation passage; (g) Exhaust gas recirculation amount adjustment means that adjusts the amount of exhaust gas flowing through the exhaust gas recirculation passage; Storage means consisting of an electric memory for storing the set exhaust gas recirculation rate; (h) Exhaust recirculation rate = (K・P _M −Q _a /N) from the intake air amount Q _a , rotational speed N, and intake pipe pressure P _M )/(K P _M ) where K is a constant.The actual exhaust gas recirculation rate is determined based on the formula, and the above-mentioned An exhaust recirculation control device comprising an exhaust recirculation control means for controlling an exhaust gas recirculation amount adjustment means.