JPH03213660A - Fuel control device for engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a temporary over-rich phenomenon at the time of deceleration by constituting auxiliary air to be supplied into an intake passage at the time of deceleration in an engine in which fuel injection is controlled based on the pressure within the intake passage. CONSTITUTION:When an engine is in operation, intake pressure is changed owing to the opening and/or closing of respective throttle valves 241 and 242 and the like. In this case, change in intake pressure is detected by an intake pressure sensor 32 so that the result of the detection is inputted into an ECU 40. The quantity of fuel injection is then properly controlled based on the detected intake pressure, engine revolution and the like. When a decelerating operation condition is detected in a fuel control device as described above wherein intake pressure is abruptly lowered with the throttle valve abruptly and fully closed, an AAV (anti-after burn valve) 36 is opened, and auxiliary air from an air pump is constituted to be supplied to respective law loading independent intake passage 161 from air blow-out ports 37 with air-fuel mixture leaned so that the occurrence of an over-rich phenomenon is thereby prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for controlling the amount of fuel injected into an engine.

[Conventional technology]

Conventionally, engines in which the amount of fuel injection is adjusted by electronic control are equipped with an air flow meter or a hot wire type air sensor to detect the intake flow rate, and the amount of fuel injection is set based on the detection signal. It has become common to

However, since the air flow meter and hot wire type air flow sensor are relatively large, they are disadvantageous in terms of layout, tend to increase intake resistance, and tend to have a delayed response. Therefore, in recent years, as shown in Japanese Patent Application Laid-Open No. 59-15656, for example, an intake pressure sensor (MAR sensor) that detects the pressure inside the intake pipe has been installed, and based on the pressure detected by this sensor, a data map etc. is used to calculate the fuel consumption. Devices that set the injection amount have come to be known.

[Problem to be solved by the invention]

Generally, when the throttle valve of an engine is suddenly closed during deceleration, the negative pressure on the downstream side of the throttle valve temporarily increases, and this pressure carries the fuel adhering to the inner wall of the intake pipe to the combustion chamber. , over-richness may cause afterburn.

As a means to avoid this situation, A that detects the flesh pressure of the ventilation pipe during deceleration and automatically supplies auxiliary air into the intake pipe.
AV (＾nti Afterburn Valve)
It has come to be known that such an auxiliary air supply means is provided in an engine in which the amount of fuel injection is controlled based on the intake pressure as described above. In this case, the intake pressure sensor reads the pressure change due to the supply of the auxiliary air and increases the fuel injection amount, which may reduce the effect of diluting the fuel by the auxiliary air.

In view of these circumstances, the present invention provides fuel control that can perform appropriate fuel control based on intake pressure and can effectively prevent overrich phenomena caused by changes in intake pressure during deceleration. The purpose is to provide equipment.

[Means for Solving the Problems] The present invention provides fuel control for an engine that includes pressure detection means for detecting pressure in an intake passage, and control means for controlling fuel injection amount based on the detected pressure. In the device,
An auxiliary air supply means for supplying auxiliary air into the intake passage during deceleration is provided, and a pressure extraction part for detection by the pressure detection means is provided in the intake passage upstream of the air supply part by the auxiliary air supply means. It is placed on the side.

[For production]

According to the above configuration, the fuel injection amount is controlled based on the pressure in the intake passage, and the auxiliary air supply means supplies auxiliary air during deceleration, thereby preventing overrich from occurring. Moreover, since the pressure extraction part is provided at a position upstream of the air supply part by the auxiliary air supply means, the influence of the supply of the auxiliary air on the detection results of the pressure detection means is extremely small. The fuel injection amount is almost never increased with the supply of air.

〔Example〕

The figure shows the overall configuration of an engine in one embodiment of the present invention. Note that although a 〇-Tary engine is shown here as an example, the present invention is not limited to this and can be applied to other engines such as a reciprocating engine.

In the above figure, 10 is an engine main body, cylinders are provided before and after the engine main body, and each cylinder is provided with a rotor 12. A low-load intake boat 1 is located at a position facing into each cylinder.
41 and a high-load intake boat 142 are formed, and the low-load intake boat 141 has an independent low-load intake passage 161.
However, a high-load independent intake passage 162 is connected to the high-load intake boat 142 . Independent intake passage for each low load 1
61 joins the low-load collective intake passage 181 on its upstream side, and each high-load independent intake passage 162 joins the high-load collective intake passage 182 on its upstream side, and The passage 181 and the high load collective intake passage 182 are
It joins the collective intake passage 20 on its upstream side.

An air cleaner 22 is provided in this collective intake passage 20. A low-load throttle valve 241 is provided in the low-load collective intake passage 181 on the downstream side, and a high-load throttle valve 242 is provided in the high-load collective intake passage 182. The low load throttle valve 241 is opened as appropriate during both low load and high load, and the high load throttle valve 242 is opened only during high load. Load intake passage 1
Air is taken in only from 61 and 181, and when the load is high, air is also taken from high load intake passages 162 and 182.

Each independent intake passage 161,162 has these passages 16
An injector 26 is arranged which supplies fuel directly into the 1.162. In addition, the upstream and downstream parts of the low-load throttle valve 241 are ISO (Idle 5p).
eed Control) passage 28, and an ISC valve 29 is provided in this ISC passage 2B.
These control the engine speed at idle.

The pressure (negative pressure) in each low-load independent intake passage 161 is
A pressure take-out port 31 is provided for taking out the pressure, and each pressure take-out port 31 is connected to a common intake pressure sensor (MAP sensor: pressure detection means) 32 via a pressure take-out passage 30. This intake pressure sensor 32 detects the pressure in the low-load independent intake passage 161 transmitted through the pressure extraction passage 30 and converts it into an electric signal, and the detection signal is sent to the ECU (control means). 40 is input.

Furthermore, in this device, each low-load independent intake passage 161
An air outlet 37 is provided at a position on the downstream side of the pressure outlet 31, and an air pump (not shown) is connected to each air outlet 37 via an air supply passage 34. is A AV (Ant
i Afterburn Valve) 36 is provided.

This AAV36 consists of a diaphragm, and opens when the low-load throttle valve 241 closes during deceleration and the intake pressure suddenly drops, and the air-fuel mixture becomes rich as the intake pressure suddenly drops. Sometimes, the above AAV36
is opened and auxiliary air is supplied to the low-load independent intake passage 161, thereby preventing afterburn due to over-richness.

In addition to the intake pressure sensor 32, the ECU 40 receives detection signals from a throttle sensor 38, an engine speed sensor (not shown), a water temperature sensor, an atmospheric pressure sensor, an intake temperature sensor, and the like. This ECU 40 is configured to control the actual fuel injection amount based on the intake pressure detected by the intake pressure sensor 32 and the engine rotation speed.

Next, the operation of this device will be explained.

While the engine is running, the intake pressure changes due to the opening and closing of each throttle valve 241, 242, etc., and this change is detected by the intake pressure sensor 32, and the detection result is
It is input to the CU 40. The ECU 40 controls the appropriate amount of fuel injection based on the detected intake pressure and engine speed.

During such driving, when the throttle valve is suddenly fully opened during deceleration and the intake pressure drops rapidly, fuel adhering to the inner wall of the intake pipe will be carried into the combustion chamber. By opening the AAV 36 when the pressure decreases, auxiliary air is automatically supplied from the air outlet 37 into each low-load independent intake passage 161, and the air-fuel mixture is diluted, thereby preventing an overrich phenomenon. .

Here, if the auxiliary air supplied through the AAV 36 affects the pressure detection of the intake pressure sensor 32, the fuel injection amount will be increased accordingly, and the effect of diluting the air-fuel mixture by the auxiliary air will be weakened. In the device, as shown in the figure above, a pressure outlet 31 for detecting the intake pressure sensor 32 is provided at a position upstream of the auxiliary air outlet 37, so that the auxiliary air is The influence on the detection result of the intake pressure is suppressed to a minimum, and the dilution effect by the AAV 36 is maintained.

Furthermore, as shown in this embodiment, ■SC passage 28
If the outlet for the air passing through is provided on the upstream side of the pressure outlet 31, changes in the intake pressure caused by opening and closing of the ISC valve 29 can be accurately read by the intake pressure sensor 32.

In addition, in this embodiment device, the pressure extraction section for detecting the pressure inside the intake pipe is connected to a low-load independent intake passage 161 which has a relatively small intake air amount and has a small pulsation amplitude even under high load.
Since the above-mentioned pulsation amplitude is provided in the intake pressure sensor 3
The effect on the detection results of 2 is extremely small, and therefore,
The intake pressure can be accurately detected in a wide range of operating ranges from low load to high load, which has the effect of always performing appropriate fuel control.

Note that the present invention can be widely applied to engines in which fuel control is performed based on intake pressure, regardless of the specific structure of the intake device. For example, the present invention is not limited to having two intake passages for each cylinder, one for low load and one for load, as shown in the above embodiment, but is also applicable to those in which each cylinder has a single intake passage. The same effect as above can also be obtained.

〔Effect of the invention〕

As described above, in a device that controls the fuel injection amount based on the pressure in the intake passage, the present invention supplies auxiliary air into the intake passage during deceleration. In addition, it is possible to prevent the occurrence of a temporary overrich phenomenon when the pressure is detected by the pressure detection means. Since the auxiliary air is provided at the position of , the auxiliary air has almost no effect on the intake pressure detection results.

This has the effect of maintaining the dilution effect of the auxiliary air.

[Brief explanation of drawings]

The figure is a configuration diagram of an engine intake system according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Engine body, 161... Independent intake passage for low load, 26... Injector, 31... Pressure outlet, 32... Intake pressure sensor (pressure detection means), 36
...AVV (auxiliary air supply means), 37...auxiliary air outlet, 40...ECLI (control means). engine body n

Claims (1)

[Claims] 1. In an engine fuel control device comprising a pressure detection means for detecting the pressure in the intake passage and a control means for controlling the fuel injection amount based on the detected pressure, an auxiliary gas is inserted into the intake passage during deceleration. An auxiliary air supply means for supplying air is provided, and a pressure take-off part for detection by the pressure detection means is provided in the intake passage at a position upstream of the air supply part by the auxiliary air supply means. Features: Engine fuel control device.