JPS6338642U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a preferred embodiment of the exhaust gas recirculation device according to the present invention, Fig. 2 is a flowchart showing the control flow of this embodiment, and Fig. 3 is the output of the oxygen concentration sensor. Figure 4 is a diagram showing the relationship between current value and air-fuel ratio. Figure 4 is a diagram showing the relationship between air-fuel ratio that changes due to EGR and the amount of exhaust black smoke emitted as NOx and exhaust particulate. FIG. 6 is a diagram showing the flow rate characteristics of the exhaust recirculation valve and intake throttle valve with respect to the signal negative pressure of the example, and FIG. 6 is a diagram showing the relationship between the load and EGR amount obtained by the control of this example, and FIGS. FIG. 10 is a diagram for explaining the general relationship between the load of a diesel internal combustion engine, the air-fuel ratio, and the air-fuel ratio and the exhaust amount of exhaust particulate. In the figure, 3 is an exhaust pipe, 5 is an exhaust recirculation valve, 6 is an intake throttle valve, 5a, 6a are diaphragms, 7 is a valve opening control means, 9 is a negative pressure supply pipe, 10 is a vacuum switching valve, 12 is an oxygen concentration sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A sensor for detecting the oxygen concentration in exhaust gas, and calculating an air-fuel ratio based on the detected value of the sensor,
An exhaust gas recirculation device comprising: valve opening control means for controlling an exhaust recirculation valve and an intake throttle valve so that the air-fuel ratio becomes equal to a set air-fuel ratio. (2) The opening and closing directions of the exhaust gas recirculation valve and the intake throttle valve are controlled in opposite directions by signal negative pressure supplied to the diaphragm at the same time, and the valve opening means is controlled by the oxygen The air-fuel ratio is detected based on the output signal from the concentration sensor, and the vacuum switching valve installed in the negative pressure supply pipe is duty-controlled so that the detected value becomes equal to a pre-stored set value. The exhaust gas recirculation device according to claim 1, which is configured to vary the signal negative pressure.