JPS59110840A - Air-fuel ratio control device in engine provided with supercharger - Google Patents

Abstract

PURPOSE:To make it possible to monitor supercharged pressure with a simple device, by detecting an intake-air pipe pressure (supercharged pressure) with the use of an intake-air amount sensor and a rotational speed sensor which are used for controlling the air-fuel ratio of an engine, and as well by displaying the pressure on a display means. CONSTITUTION:An internal combustion engine provided with a supercharger includes an air-fuel ratio control section 121 in an arithmetic operating device 120, which computes the amount of fuel for producing a predetermined air-fuel ratio in accordance with the outputs of an intake air amount sensor 4 and a rotational speed sensor 9, and controls a fuel injection valve 5 at predetermined timing. In this case, the arithmetic operation device 120 is further provided with a pressure detecting section 122 to which the output signals from both sensors 4, 9 are fed. Further, this pressure detecting section 122 produces an electrical signal in accordance with a value Q/N, that is, the intake air amount Q is divided by the rotational speed N. This electrical signal, after being amplified, is displayed on a display meter 110, thereby monitor is made to supercharged pressure by reading the deflection of a needle on this meter 110.

Description

[Detailed Description of the Invention] Is this invention a supercharger? The present invention relates to an air-fuel ratio control device for an engine having a supercharger and displaying the supercharging state of the engine having an electronically controlled air-fuel ratio control device.

In automobile engines equipped with a supercharger, (1) the supercharging pressure is displayed as a driving indicator for the driver, and (2) the supercharging pressure is displayed to prevent the supercharging pressure from rising abnormally and causing damage to the engine. It is desirable to indicate the supercharging state, that is, the supercharging pressure, for the purpose of warning the driver. In particular, (2)
Warnings about abnormal boost pressure are essential to prevent serious accidents. Conventionally, in order to display all of this, boost pressure is detected by a total pressure sensor or pressure switch, and a meter or lamp is used to display the alarm. The system uses a method of displaying warnings using the following display means.

FIG. 1 shows a conventional air-fuel ratio control device for an engine having a supercharger. In FIG. 1, 1 is an engine, 2 is an intake pipe, and 3 is an exhaust pipe.

The intake pipe 2 is provided with an intake air amount sensor 4.

This intake air amount sensor 4 detects the intake air amount (1) to the engine 1 and outputs it to the arithmetic unit 12.

In addition, a fuel injection valve 5 and a throttle valve 6 are located near the engine 1.
, a pressure sensor 7 (pressure switch) are provided.

A gear 8 having a convex portion at a position corresponding to the top dead center of the engine 1 and interlocked with engine rotation is provided, and a proximity switch 9 is moved by the convex portion of the gear 8. This proximity switch 9, the fuel injection valve 5, and the pressure sensor 7 are connected to an arithmetic unit 12.

Furthermore, the engine 1 is also provided with a temperature sensor 10,
This temperature sensor 10 is also connected to a calculation device 12.

Further, a display means 11 such as a meter or a lamp is connected to the pressure sensor 7.

Note that 13 is a supercharging blower which is connected to an exhaust turbine 14 via a shaft 15.

Next, to explain the operation of the device shown in FIG. are doing.

Since the intake air amount sensor 4 is a known device, a detailed explanation will be omitted. The calculation device 12 calculates the amount of intake air based on the output of the intake air amount sensor 4, and calculates the amount of fuel constituting a predetermined air-fuel ratio.

Furthermore, the arithmetic unit 12 forms a pulse signal and pulses 1
The amount of fuel per cycle is calculated and given to a pulse signal with a time width commensurate with this amount. This pulse signal is amplified by an amplification means in the arithmetic unit 12 and pulse-driven to the rear outlet nl fuel injection valve 5'. By this, the fuel injection valve 5
In order to inject a predetermined amount of fuel, the opening/closing control is performed by the arithmetic unit 12, which is supplied with a pulse by the proximity switch 9 and the gear 8 every time the engine 1 reaches the top dead center. Since this pulse for each top dead center corresponds to the rotation speed of the engine 1, it is calculated as a setting parameter for the air-fuel ratio according to the rotation speed, and it affects the time width of the driving pulse of the fuel injection valve 5 mentioned earlier. That's what I do.

In addition, there are 12 calculation units and a temperature sensor 1 that detects the engine width.
It receives an output of 0 and is used as a setting parameter for the air-fuel ratio corresponding to the temperature.

The above air-fuel ratio control operation is a well-known technique, and a more detailed explanation will be omitted.

Now, the pressure sensor (pressure switch) 7 is connected to a port provided downstream of the throttle valve 6 of the intake pipe 2.
This is a known device consisting of a diaphragm or the like that responds to the pressure within the intake pipe 2, and generates an N-side signal in response to the pressure.

7 according to this pressure? : The electric power signal is applied to the display means 11, and displays according to the suction pipe pressure.

This display can be an analog display depending on the boost pressure, or
It is also possible to display the lamps in accordance with the abnormal boost pressure.

In addition, the electric output of the pressure sensor (pressure switch) 7 is also given to the arithmetic unit 12, and when the intake pipe pressure (supercharging pressure) increases abnormally, the pulse that drives the fuel injection valve 5 is stopped. Therefore, engine 1 stops. This fuel supply stop function is an extremely important function in an air-fuel ratio control device for the engine 1 having a supercharger.

That is, the exhaust turbine 14Fi is strongly energized when the engine output is large, and therefore the supercharging blower 13 linked to this is strongly energized to strengthen the supercharging and further increase the engine output, which is a positive feedback. Because of the system structure, there is a concern that when the boost pressure rises abnormally, if left unchecked, the output will increase to the point of damage to the engine.

Therefore, when an abnormal boost pressure is detected, an effective and reliable safety measure is to stop the fuel supply as described above in order to stop the engine.

However, the above-mentioned safety measures are rarely required, and simply displaying the supercharging state on the display means 11 is not directly related to engine operation, and the performance of the pressure sensor (pressure column) 7 cannot be said to be directly related to the engine operation. cannot be said to be very high.

Furthermore, EGR gas (not shown) is injected into the intake pipe 2.
In addition, there is a high risk that deposits may adhere to the operating part of the pressure sensor (pressure cass inch) 7 and interfere with its operation due to the fact that exhaust gas from the engine is blown back into the intake pipe 2.

This malfunction is fatal when the purpose is to protect against abnormal boost pressure that rarely requires operation.

This invention was made in view of the above circumstances, and eliminates the pressure sensor (pressure switch) with low performance and low reliability, and increases the output of the intake air amount sensor divided by the output of the total rotation speed sensor (hereinafter referred to as Q/N). To provide an air-fuel ratio control device for an engine having a supercharger, which is capable of displaying supercharging pressure with high reliability by using a supercharger, and which is economically advantageous without increasing the scale of the device. With the goal.

Embodiments of an air-fuel ratio control device for an engine having a supercharger according to the present invention will be described below with reference to the drawings.

FIG. 2 shows one embodiment of the invention, and parts unnecessary for the explanation of the invention are omitted. In FIG. 2, reference numeral 120 denotes an arithmetic unit, which is composed of an air-fuel ratio control section 121 and a pressure detection section 122.

The air-fuel ratio control section 121 has a function equivalent to that of the arithmetic unit 12 shown in FIG. 1, and the explanation of its operation will be omitted since it would be redundant. Further, the pressure detection section 122 receives the output of the intake air amount sensor 4 and the output of the proximity switch 9 according to the rotation speed. The pressure detection unit 122 is shown in FIGS. 3 and 4.
The configuration is as shown in the figure.

In FIG. 3, the 123ii dividing section is the intake air amount Q
Q/N is calculated and output using an electric signal according to the rotation speed N and an electric signal according to the rotation speed N.

The intake air amount Q of the engine is expressed as QP, N, and η by the intake pipe pressure P, the engine speed N, and the volumetric efficiency 7.

Therefore, since there is a relationship such as Q/Noc P, η, the value of Q/N is considered to be indicated by the intake pipe pressure P'.
Ru. Here, it is safe to assume that the volumetric efficiency is constant within the normal operating range of the engine.

Therefore, the electrical output Q/Nk of the dividing unit 123 is
When the width is increased and displayed on the display meter 110, the pointer of the display meter 110 will display the intake pipe pressure.

Next, in FIG. 4, 123 is the same as the divider 13 in FIG. 3, and the output Q/N of this divider 123 is compared with the reference signal 126 by a comparison amplifier 125. .

The output of the comparison amplification section 125 is connected to an indicator lamp.

Now, the operation of the dividing section 123 is as explained with reference to FIG. 3, and all electrical signals are generated according to the intake pipe pressure. The reference signal 126 is an electric signal corresponding to the limit value of the intake pipe pressure (supercharging pressure), that is, the abnormal supercharging pressure set value. (supercharging pressure), and if the intake pipe pressure rises abnormally, the indicator lamp 111 is lit. The reference signal 126 can also be set to correspond to two large pressures, and it goes without saying that in this case the indicator lamp 111 will indicate the start of supercharging of the engine.

Although the volumetric efficiency was approximated as constant above, strictly speaking, n changes depending on the state of the engine, that is, the intake air amount Q and the rotation speed N. Therefore, the division unit 123 in FIGS. 3 and 4
It goes without saying that if the value of Q/H is corrected using both input parameters, it is possible to more accurately indicate the intake pipe pressure P'(+7).

As described above, in the air-fuel ratio control device for an engine having a supercharger according to the present invention, the pressure sensor (pressure switch) 111 with low reliability for detecting the intake pipe pressure is not used and the air-fuel ratio control device for the engine is not used. The intake pipe pressure is fully detected by fully utilizing the intake air amount sensor and the rotation speed sensor, which makes it possible to display the supercharging pressure with high reliability.

In addition, the division of Q/N and the comparison with the reference pressure can be performed in common with all calculation units such as the microprocessor that makes up the air-fuel ratio control unit, so there is no need to increase the scale of the equipment, so there is an economical effect. It's also a big deal.

[Brief explanation of drawings]

FIG. 1 shows a schematic configuration of a conventional air-fuel ratio control device for an engine having a supercharger. FIG. 2 is a diagram showing the configuration of an embodiment of an air-fuel ratio control device for an engine having a supercharger according to the present invention, and FIGS. 1 is a block diagram showing a configuration example of a pressure detection section in an air-fuel ratio control device of 1...engine, 2...intake pipe, 3...
Exhaust pipe, 4... Intake amount sensor, 5... Fuel injection valve,
120... Arithmetic device, 121... Air-fuel ratio control unit, 1
22...Pressure detection section, 123...Divide section, 125.
... Comparison amplifier section, 110 ... Display meter, 111 ...
・Indication lamp. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Procedural amendment (voluntary) Commissioner of the Japan Patent Office 1, case description Possessed IQ [1lIf: 57-2
No. 22534 No. 2, Title of the invention Air-fuel ratio control device for an engine with a supercharger 3, Person making the amendment Representative: Hitoshi Katayama Department 4, Agent 5, Claims of the specification to be amended and details of the invention Column 6 of the explanation and each of the amendments (1) The entire scope of claims in the description is corrected as shown in the appendix. (2) On page 6, line 9, "(pressure rande)" is corrected to "(pressure switch)". 7. Amendment of list of attached documents Scope of patent claims 1 or more copies 2. Claims: An intake air amount sensor that detects the intake air amount of an engine, a rotation speed sensor that detects the entire rotation speed of the engine, and at least the above intake air amount. A calculation that receives all the outputs of the sensor and rotational speed sensor, generates an electric signal corresponding to the value obtained by dividing the output of the intake air amount sensor by the output of the rotational speed sensor, and supplies it to the display means that displays the supercharging state of the engine. An air-fuel ratio control device for an engine, which has a supercharger and a fuel injection valve that supplies the entire engine.

Claims (1)

[Claims] An intake air amount sensor that detects the intake air amount of the engine, a rotation speed sensor that detects the engine rotation speed, and a rotation speed sensor that receives the outputs of at least the intake air amount sensor and the rotation speed sensor. A supercharging system consisting of a calculation device that generates an electrical signal according to the value divided by the output and supplies it to a display means that displays the supercharging state of the engine, and a fuel injection valve that receives the electrical signal and supplies fuel to the engine. Air-fuel ratio control device for an engine with a feeder.