JPH02227525A - Air-fuel ratio control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To ensure proper air-fuel ratio required by an internal combustion engine by setting a correction zone corresponding to an engine revolution number and by correcting a specific air-fuel ratio by a correction amount set for the correction zone, when fuel used in the internal combustion engine is not a specific fuel. CONSTITUTION:Based on each of detecting signals from various sensors 60 to 72 for detecting driving state of an internal combustion engine 2, a passage for pressure control 52 is opened and closed via a pressure control valve 54 by a control means 58, whereby changes pressure in a pressure chamber 38 in an actuator 32. And an inlet 26 is opened and closed by a waste gate valve 30, displacement flowing through a bypass passage 24 is adjusted and supercharging pressure is controlled. At this time, when fuel used in the internal combustion engine is not a specific fuel, a correction zone corresponding to an engine revolution number is set by the control means 58. And a specific air-fuel ratio is corrected by the correction amount set for the correction zone so as to control to the air-fuel ratio required by the internal combustion engine 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air-fuel ratio control device for an internal combustion engine, and in particular, it controls the operating performance by maintaining the appropriate air-fuel ratio required by the internal combustion engine even when the fuel used is other than a specific fuel. The present invention relates to an air-fuel ratio control device for an internal combustion engine that can improve performance.

[Conventional technology]

BACKGROUND ART In internal combustion engines such as vehicles, in order to reduce fuel consumption rates and harmful exhaust gas components, feedback control type air-fuel ratio control devices have been proposed that converge to the air-fuel ratio that should provide the best combustion state.

Furthermore, a device for controlling the combustion state of an internal combustion engine is disclosed in, for example, Japanese Patent Laid-Open No. 62-233428. The system described in this publication causes a return from the second control characteristic to the first control characteristic when the fuel increases to a predetermined value or more while the vehicle is stopped, and prevents any (unrelated sudden) change in the fuel octane number. It reliably eliminates the noise caused by fluid level fluctuations in the fuel tank during start-offs, sharp turns, etc., and more accurately detects whether or not fuel has been refueled, i.e., whether the octane number may have changed, and prevents unnecessary combustion. This is to prevent changes in the

Furthermore, in internal combustion engines, fuels with different properties, such as regular gasoline or high-octane gasoline, may be supplied, and in this case, the properties of the fuel used are determined and the air-fuel ratio is controlled according to the fuel used. There is a need.

For example, as an internal combustion engine that determines the fuel used,
It is disclosed in Japanese Patent No. 0-75731.

The device described in this publication has a configuration that automatically and accurately determines the fuel used without adversely affecting driving performance.

On the other hand, some internal combustion engines with a supercharger are controlled to a specific air-fuel ratio set in accordance with high-octane gasoline as the specific fuel. In this case, as shown in Figure 6, when regular gasoline, which is a fuel other than the specified fuel, is used as fuel, the boost pressure is lowered than when using high-octane gasoline to avoid non-king. ing.

[Problem that the invention seeks to solve]

However, in the above-mentioned supercharged internal combustion engine, when the fuel used is other than the specified fuel, that is, when regular gasoline is used, the supercharging pressure is controlled to avoid the occurrence of non-king, but the fuel supply amount is Since it is supplied with the value set for specific fuel, that is, high octane gasoline,
Due to the difference in the amount of intake air, it is difficult to obtain the optimum air-fuel ratio when using regular gasoline, resulting in the inconvenience of reduced driving performance.

In addition, if the air-fuel ratio fluctuates unnecessarily in this way, the temperature of exhaust system parts, etc. may exceed the allowable limit temperature, reducing the performance of the internal combustion engine, and in the worst case, the internal combustion engine or supercharger may fail. This caused the inconvenience of damage.

[Purpose of the invention]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, an object of the present invention is to set a correction area corresponding to the engine speed when the fuel used in the internal combustion engine is other than a specific fuel, and to adjust the correction amount to a specific air-fuel ratio by the correction amount set in the correction area. By correcting and controlling the air-fuel ratio to the required air-fuel ratio of the internal combustion engine, even when the fuel used is other than the specified fuel, the operating performance can be improved to the appropriate air-fuel ratio required by the internal combustion engine, and the internal combustion engine, etc. can be protected. The object of the present invention is to realize an air-fuel ratio control device for an internal combustion engine.

[Means for solving problems]

In order to achieve this object, the present invention provides an air-fuel ratio control device for an internal combustion engine that controls the air-fuel ratio to a specific air-fuel ratio set according to a specific fuel, in which when the fuel used in the internal combustion engine is other than the specific fuel, the engine speed increases. The present invention is characterized by further comprising a control means for setting a correction area corresponding to the number of correction areas and correcting the specific air-fuel ratio by the correction amount set in this correction area to control the air-fuel ratio to the required air-fuel ratio of the internal combustion engine.

[Effect]

According to the configuration of the invention, the control means sets a correction area corresponding to the engine speed when the fuel used by the internal combustion engine is other than the specific fuel, and corrects the specific air-fuel ratio by the correction amount set in the correction area. The air-fuel ratio is controlled to the required air-fuel ratio of the internal combustion engine. Thereby, even when the fuel used is other than the specified fuel, it is possible to obtain the appropriate air-fuel ratio required by the internal combustion engine, improve driving performance, and protect the internal combustion engine and the like to improve durability.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

1 to 5 show a first embodiment of the invention. In FIG. 1, 2 is an internal combustion engine, 4 is a compressor 6
and an exhaust turbine 8, 10 is an intake passage, and 12 is an exhaust passage. An air cleaner 16 is provided in the first intake passage 10-1 on the upstream side of the compressor 6 of the supercharger 4 via an air flow meter 14, and an ink cooler 18 and an intake passage are provided in the second intake passage 10-2 on the downstream side of the compressor 6. A surge tank 22 is provided via a throttle valve 20. The internal combustion engine 2 also has a first exhaust passage 1.
The exhaust turbine 8 of the supercharger 4 is provided on the downstream side of 2-1,
A second exhaust passage 12-2 communicates with the downstream side of the exhaust turbine 8.

The first exhaust passage 1 bypasses the exhaust turbine 8 of the supercharger 4.
A bypass passage 24 is provided to communicate between the exhaust passage 2-1 and the second exhaust passage 12-2. One end of the bypass passage 24 communicates with an inlet 26 that opens into the first exhaust passage 12-1, and the other end communicates with an outlet 28 that opens into the second exhaust passage 12-1. This bypass passage 24
The inlet 26 is opened and closed by a wastegate valve 30. This wastegate valve 30 is operated by an actuator 3
2.

This actuator 32 has a pressure chamber 38 and an atmospheric chamber 40 defined by a diaphragm 36 in a main body 34 . An operating rod 4 is attached to one side of this diaphragm 36.
One end of the actuating rod 42 is connected to the operating rod 42, and the other end of the operating rod 42 is connected to a rotating lever 44 connected to the waste gate valve 30.

Further, the atmospheric chamber 40 of the actuator 320 main body 34
A spring 46 is disposed to bias the diaphragm 36 in the direction in which the pressure chamber 38 is contracted.

The pressure chamber 38 of the actuator 32 is opened at the other end of a pressure guiding passage 48 whose one end is opened to the second intake passage 10 - 2 on the downstream side of the supercharger 4 .

Further, on one end side of this pressure guiding passage 48, a first constriction portion 50 is provided.
is provided.

A pressure control passage 52 communicates in the middle of this pressure-control passage 48, with one end communicating with the pressure-control passage 48 and the other end communicating with the first intake passage 10-1 on the upstream side of the supercharger 4. There is.

A pressure control valve 54, which is a duty solenoid, is provided in the middle of the pressure control passage 52 and is operated according to a duty value in order to adjust the pressure acting on the pressure chamber 38 of the actuator 32 from the pressure guiding passage 48. Further, in the pressure control passage 52, a pressure control valve 54 is connected to the pressure control passage 48 from the pressure control valve 54.
A second constriction portion 56 having a predetermined opening area is provided to adjust the pressure acting on the second constriction portion 56 to a predetermined value.

The pressure control valve 54 includes a control means 5 for controlling the operation of the pressure control valve 54 in order to control the supercharging pressure according to each control factor.
8 is in contact.

This control means 58 includes an ignition signal detection section 60 that detects the engine speed, an intake air temperature sensor 62 that detects the intake air temperature, a cooling water temperature sensor 64 that detects the cooling water temperature of the internal combustion engine 2, and an atmospheric pressure sensor 64 that detects the temperature of the cooling water of the internal combustion engine 2. An atmospheric pressure sensor 66 for detecting acceleration, a vehicle speed sensor 68 for detecting acceleration, a knock sensor 70 for detecting non-king, and a throttle sensor 72 are in communication. Furthermore, a battery 74 is connected to the control means 58 .

Further, the internal combustion engine 2 is controlled to a specific air-fuel ratio set in accordance with high-octane gasoline, which is a specific fuel.

On the other hand, when the fuel used in the internal combustion engine 2 is regular gasoline other than high-octane gasoline, the control means 58 controls the correction range (χo1χ1, χ2,
...χn) (see Figure 4.5) and the correction amounts (yO, y1, y2, . . .
・yn) (see Figure 5) to correct the specific air-fuel ratio,
For example, the amount of fuel supplied and the amount of intake air are adjusted (by operating each control mechanism (not shown) to control the air-fuel ratio to the required air-fuel ratio of the internal combustion engine 2. The correction area is as shown in FIG.
It is set based on the engine speed and load.

Next, the operation of this embodiment will be explained by the flowchart shown in FIG.
This will be explained based on the timing chart of FIG.

As shown in FIG. 3, the pressure control valve 54 is normally operated and controlled by a preset open duty value (OPDTY) to open and close the pressure control passage 52. and,
When accelerating, the control means 58 controls the amount of change in the throttle valve 20;
The acceleration state is determined based on the amount of change in intake air, etc., and the duty value of the pressure control valve 54 is corrected for a certain period of time, and then the duty value is attenuated by integrating the time.

Then, it is determined whether the fuel used is regular gasoline or not (step 102), and if it is regular gasoline and step 102 is YES (as shown by position A in FIG. 3),
In step 104, 0PDTY=OPDTY (
When refueling with high-octane gasoline) x R (%) (R: a constant of 1 or less) In other words, it is R times the 7-knob value of open duty value control.

Or, 0PDTY=RG (%) (RG - duty value % when refueling with regular gasoline). As a result, the pressure control valve 54 opens and closes the pressure control passage 52 to change the pressure in the pressure chamber 38 of the actuator 32, and the wastegate valve 30 opens and closes the pressure control passage 52.
Opening and closing to adjust the amount of exhaust gas flowing through the bypass passage 24,
Controls boost pressure.

Next, the value of the engine rotational speed is input, and it is determined in step 106 whether or not it is in the correction area. If it is a correction area and YES in step 106, a plurality of correction coefficients (χO1χ
1, χ2, ... yn), and each correction coefficient (
The fuel supply amount, intake air amount, etc. are changed by the air-fuel ratio correction amount (yO, )'1, )'2, ... yn) set corresponding to χO1χ1, χ2, ... yn), and the specified The air-fuel ratio is corrected to appropriately control it to the required air-fuel ratio of the internal combustion engine 2.

This correction control ends when the engine speed and load change and go out of the correction range (as shown by position B in FIG. 3). That is, as shown in FIG. 3, the specific air-fuel ratio is corrected to the required air-fuel ratio by the time t from position A where regular gasoline is determined to position B where it is no longer in the correction area.

On the other hand, if it is not regular gasoline and the answer is No in step 102, and if it is not in the correction range and is No in step 106, the specific air-fuel ratio is not corrected.

As a result, the internal combustion engine 2 is equipped with a supercharger 4 and is controlled to a specific air-fuel ratio set in accordance with high-octane gasoline.
Even when regular gasoline is used, when the pressure control valve 54 is operated to control the boost pressure, the fuel system and intake system are operated and controlled in response to this boost pressure to control the air pressure. Since the fuel ratio can be controlled appropriately, even when the fuel used is high-octane gasoline or regular gasoline, the optimal air-fuel ratio can be obtained and driving performance can be improved.

In addition, since the air-fuel ratio can be controlled appropriately, it is possible to suppress the permissible temperature limit of exhaust system parts, etc., and prevent damage to the internal combustion engine 2, supercharger 4, etc. The feeder 4 can be protected and its durability can be improved.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention,
When the fuel used by the internal combustion engine is other than a specific fuel, a correction area corresponding to the engine speed is set, and the specific air-fuel ratio is corrected by the correction amount set in the correction area to control the air-fuel ratio to the required air-fuel ratio of the internal combustion engine. By providing the means, even when the fuel used is other than the specific fuel, the air-fuel ratio required by the internal combustion engine can be adjusted to improve the operating performance, and the internal combustion engine, etc. can be protected.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, FIG. 1 is a schematic diagram of an air-fuel ratio control device for an internal combustion engine, FIG. 2 is a flowchart explaining the operation of this embodiment, and FIG. 3 is an open duty system. Timing chart of value control and air-fuel ratio correction, 4th
The figure is an explanatory diagram showing a correction area set based on engine speed and load, and FIG. 5 is a diagram explaining a table of engine speed, correction area, and correction amount. FIG. 6 is a diagram showing boost pressure control when using high-octane gasoline and when using regular gasoline, respectively. In the figure, 2 is an internal combustion engine, 4 is a supercharger, 10 is an intake passage, 18 is an intake throttle valve, 24 is a bypass passage, 26 is an inlet, 28 is an outlet, 30 is a wastegate valve, 32 is an actuator, and 38 is a a pressure chamber, 48 a pressure guiding passage, 52 a pressure control passage, 54 a pressure control valve, 58 a control means;
60 is an ignition signal detection unit, 62 is an intake air temperature sensor, 6
4 is a cooling water temperature sensor, and 72 is a throttle sensor.

Claims (1)

[Claims] 1. In an air-fuel ratio control device for an internal combustion engine that controls the air-fuel ratio to a specific air-fuel ratio set according to a specific fuel, if the fuel used by the internal combustion engine is other than the specific fuel, a correction area is set corresponding to the engine speed. An air-fuel ratio control device for an internal combustion engine, further comprising a control means for correcting the specific air-fuel ratio using a correction amount set in the correction area to control the air-fuel ratio to a required air-fuel ratio of the internal combustion engine.