JPH0240046A - Fuel feed amount control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve running performance by a method wherein when it is decided that a throttle opening detecting value is abnormal, an intake air pressure detecting value detected by an intake air pressure sensor is compared with a high load area set value lower than a high load set value during normal running to discriminate whether the high load increase of a fuel feed amount is needed. CONSTITUTION:When a throttle opening detecting value TA is normal, an intake pressure detecting value PIM having high detecting precision on a flatland is utilized and a throttle opening detecting value on a highland is utilized to properly detect the high load area of an internal combustion engine. When the throttle opening detecting value TA is abnormal, the intake air pressure detecting value PIM by an intake pressure sensor 20 is compared with a high load area set value P2 lower than a high load area set value P1, and this comparison causes detection of a high load area. Thereby, a high load area on a highland can be properly detected without increasing a high load area and a detected region on a flatland so much. This constitution causes proper control of a fuel feed amount and improves running performance as fuel consumption and exhaust gas emission are maintained in an excellent state.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a device for controlling the amount of fuel supplied according to the operating state of an internal combustion engine, and particularly for increasing the amount of fuel supplied at times of high load. The present invention relates to a fuel supply amount control device.

<Prior Art> In general, means for detecting the high load range of an internal combustion engine include means for detecting based on the intake pressure in an intake pipe and means for detecting based on the opening degree of a throttle valve.

However, when detecting the high load range of an internal combustion engine using intake pressure, although it can be detected with relatively high accuracy on flat ground,
Atmospheric pressure decreases at high altitudes, resulting in detection errors. On the other hand, when detecting high load range by throttle opening,
Currently, there is a problem with the accuracy of the throttle opening sensor, and if an abnormality occurs in the throttle opening detection value, the high load range of the internal combustion engine cannot be accurately detected.

Therefore, a technique has been proposed for detecting the high load range of an internal combustion engine based on throttle opening and intake pressure (see, for example, Japanese Patent Publication No. 62-29622). In other words, the technology disclosed in this publication detects the intake pressure and the throttle opening, and when both of these detected values are below a predetermined value, the mixture supplied to the internal combustion engine is not enriched, and the mixture is not enriched. When one of the detected values exceeds a predetermined value, the air-fuel mixture is enriched.

<Problems to be Solved by the Invention> In the technique d3 disclosed in the above-mentioned publication, when the throttle opening detected by the throttle opening sensor becomes abnormal, for example, the air-fuel mixture is unnecessary. This may cause inconveniences such as enrichment. Therefore, in such a case, the high load range of the internal combustion engine must be detected based only on the intake pressure detection value detected by the intake pressure sensor. However, as described above, although it is possible to detect a high load area with high accuracy on a flat ground based on the intake pressure detection value, it is difficult to properly detect a high load area on a high ground.

Means for Solving the Problems> The present invention is configured as follows in order to solve the above problems.

In other words, the throttle opening sensor can detect the opening of a throttle valve installed in the throttle body that communicates with the intake pipe of the internal combustion engine, and the intake pressure sensor can detect the intake pressure in the intake pipe. .

The fuel supply amount control device of the present invention is characterized in that the thrower 1
- Appropriate value determining means for determining whether a throttle opening detection value detected by the opening sensor is normal or abnormal; and comparing the throttle opening detection value by the throttle opening sensor with its high load range setting value. Throttle opening determination means for determining whether a high-load increase in the fuel supply amount is necessary; and a throttle opening determination means for determining whether a high-load increase in the fuel supply amount is necessary; a first intake pressure determination means for determining whether or not it is necessary; and when the throttle opening detection value is determined to be abnormal by the appropriate value determination means, the intake pressure detection value by the intake pressure sensor is set to a normal high value. and second intake pressure determining means for determining whether a high load increase in fuel supply amount is necessary by comparing the high load range set value which is smaller than the load range set value.

According to the above configuration, the throttle opening detection value is normal, and the intake pressure detection value with high detection accuracy is used on flat ground.
And at high altitudes, by using the throttle opening detection value,
High load areas are accurately detected.

In addition, when the throttle opening detection value is abnormal,
Compare the intake pressure detected by the intake pressure sensor with a high load range setting value that is smaller than the normal high load range setting value to determine whether a high load increase in fuel supply amount is necessary. Detection is performed. Therefore, high load areas at high altitudes can be accurately detected without significantly increasing the number of areas detected as high load areas at flatlands.

<Example> Next, embodiments of the present invention will be described with reference to the drawings.

First, in FIG. 2 schematically showing a control device for a fuel supply system of a vehicle internal combustion engine, and FIG. 3 showing a block diagram of an electronic control unit 30 shown in FIG. A throttle body 13 is connected continuously to an intake pipe 12 that communicates with a cylinder 10 of an internal combustion engine.

A throttle valve 14 is provided inside the throttle body 13, and an injector 16 for fuel injection is provided in the throttle body 13 upstream of the throttle valve 14.

A throttle opening sensor 18 is attached to the throttle body 13 for detecting the opening of the throttle valve 14 and outputting a corresponding electric signal (analog signal). Further, the intake pipe 12 detects the intake pressure on the downstream side of the throttle valve 14, and a corresponding electric signal (
An intake pressure sensor υ2o that outputs an analog signal is provided.

Furthermore, other sensors for detecting the operating state of the internal combustion engine are provided in the cylinder 1o to detect the temperature of the cooling water, and generate an electric signal (analog signal) corresponding to the temperature of the cooling water.
The water temperature sensor 22 outputs the ignition timing of the internal combustion engine, and generates an electric signal (digital signal) corresponding to the ignition timing of the internal combustion engine.
The engine is equipped with an ignition timing sensor 24 that outputs ignition timing sensor 24 and the like.

The electrical signal output from the ignition timing sensor 24 generally uses the ignition timing signal of the rib coater to the disk 1.

The electronic control unit 30 is configured using a CPU 32 such as a microcomputer, as shown in FIG.

The electrical signals output from the throttle opening detection value 18, the intake pressure sensor 20, and the hot water sensor 22 are as follows:
After being corrected by the input interface 38 shown in FIG. 3 to a level that can be processed by the electronic control unit 3Q, the signal is sampled by the A/D converter 36, converted into a digital signal, and input to the CPU 32. On the other hand, the signal output from the ignition timing sensor 24 is waveform-shaped into a rectangular wave pulse signal of a required level by the detection circuit 38, and then similarly input to the CPU 32.

The CPtJ32 temporarily stores data input therein, calculation results, etc. in the RAM40, and
The operating status of the internal combustion engine is determined according to the internal system program. This CPU 32 determines an appropriate fuel injection amount corresponding to the operating state obtained by the judgment, and
A fuel injection amount control signal is output to the drive circuit 44 of the injector 16 shown in the figure.

The amount of fuel supplied to the internal combustion engine is generally controlled by controlling the ignition timing of the internal combustion engine and the fuel injection time by the injector 16. The fuel injection cylinder time AU is determined by the following equation (1).

TAU=T1 x Kl 2 in 10...(
1) In the above formula (1), T1 is the value of the basic fuel injection time by the injector 16, and KIK2 is a correction coefficient based on various parameters in each internal combustion engine. By the way, the correction coefficient 1 is the water temperature correction coefficient KTI.
Open, opening angle high load increase coefficient WOT, acceleration increase coefficient KTCI
, deceleration reduction coefficient K Te3, etc., is determined by the following equation (2).

Kl =KTHW xKWOT xKTCl xKTC
2...XKX...(2) Now,
The contents of the software processing by the Cl) U 32 are shown in the flowchart of FIG.

The process shown in this flowchart is a type of interrupt process that is synchronized with the sampling period of the A/D converter 36 shown in FIG. 3 and is started at the time of sampling of the Δ/D converter 36.

Therefore, the processing will be explained according to the flowchart shown in FIG. First, in step 61 of FIG. 1, it is determined whether the throttle opening detection value detected by the throttle opening sensor 18 is normal or abnormal. If the throttle opening detection value is normal, in step 62, the throttle opening detection value TA is compared with its high load range setting value TΔP. Throttle opening detection value TA is higher than its high load range setting value TAP (TA≧TAP)
When , it is determined that the internal combustion engine is in a high load range, and high load control is executed in step 65.

Further, in step 62, the throttle opening detection value TA is smaller than the high load range setting value TAP (TA<TAP).
When it is determined that
1, where the intake pressure detection value 1] IM is greater than the high load range setting value P1 (
When it is determined that PIM>Pl), step 65
High load control is executed in

Further, if it is determined in step 63 that the intake pressure detection value PIM is less than or equal to the high load range setting value P1 (PIM≦PI), low load control is executed in step 66.

After the high load control or low load control is executed in step 65 or step 66, the process proceeds to step 67, where the fuel injection time PAU of the injector 16 is calculated based on the equation (1) described above.

Note that the high load range set value TAP determined by the throttle opening sensor 18 and the high load range set value P determined by the intake pressure sensor 20
First, these are the values detected by the respective sensors 18 and 20 when the operating state of the internal combustion engine is in the high load range.

In addition, the low load control by the process of step 66 is performed by adding 10■ to the high load increase coefficient in equation (2) described above.
'', and the high load control by the process of step 65 sets this high load increase coefficient KWO to a value greater than 11, for example, 11.

When the throttle opening detection value is determined to be abnormal in step 61 of FIG. 1, in step 64, the intake pressure detection value PIM detected by the intake pressure sensor 20 and the normal high load range setting value P1 The set value P2, which is a smaller value, is compared. When it is determined that the intake pressure detection value PIM is larger than the high load range setting value P2 (PIM>p2), high load control is executed in step 65. Further, in step 64, the intake pressure detection value P
When it is determined that IM is less than or equal to the high load range setting value P2 (PIM≦P2), low load control is executed in step 66.

According to the process based on the flowchart shown in FIG. 1, the high load region at high altitudes can be properly detected even when the throttle opening detection value is abnormal.

In addition, as a general means of processing in step 61, the analog signal (voltage signal) output from the throttle opening sensor 18 indicates an abnormal value (low voltage or high voltage) that cannot occur in reality, and this When detected, it may be determined that the throttle opening detection value is abnormal.

Further, as described above, the high load range setting value P2 of the throttle opening used in the process of step 64 is set to a smaller value than the high load range setting value P1 used in the process of step 63. And this P2
Even in places where the atmospheric pressure is low, such as at high altitudes, if the actual opening degree of the throttle valve 14 is too large, the internal combustion engine can be determined to be in a high load range (approximately 600 m1l).
It is set to (+,).

In the tenth embodiment, the area of the ROM 42 that stores the process of step 61 in FIG. An appropriate value determining means is configured to determine the appropriate value. Further, the area of ROM=12 which stores the process of step 62 and the CPU 32 which executes this step 62 mainly constitute the throttle opening degree determining means. Furthermore, an area of the ROM/i2 that stores the processing of steps 63 and 64, and a CPU 32 that executes the processing of steps 63 and 64.
The first intake pressure determining means and the second intake pressure determining means are mainly composed of the first intake pressure determining means and the second intake pressure determining means.

<Effects of the Invention> According to the present invention, when the throttle opening detection value is normal,
The high load range of the internal combustion engine can be appropriately detected by using the intake pressure detection value, which has high detection accuracy, in flatlands and by using the throttle opening detection value in highlands. In addition, when the throttle opening detection value is abnormal, the intake pressure detection value by the intake pressure sensor is compared with a high load range setting value that is smaller than the normal high load range setting value, and the high load range is detected based on this. Therefore, high load areas at high altitudes can be accurately detected without significantly increasing the number of areas detected as high load areas at flatlands. For these reasons, the amount of fuel supplied to the internal combustion engine can be appropriately controlled, and driving performance can be improved while maintaining good fuel efficiency and exhaust gas emissions.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, FIG. 1 shows the processing content for controlling the fuel supply amount executed by the CP ("rl-chart"), and FIG. 2 shows the intake system of the internal combustion engine. FIG. 3 is a block diagram showing the configuration of the electronically controlled unit shown in FIG. 2. . 12...Intake pipe 13...Throttle body 1/I...Throttle valve 18...Throttle opening sensor 20...Intake case sensor TA...Detected value of opening to thrower 1 TΔP...High load range setting value of throttle opening PJM・
・・Inspiratory pressure detection value

Claims (1)

[Scope of Claims] A device for controlling the amount of fuel supplied according to the operating state of an internal combustion engine, which detects the opening degree of a throttle valve provided in a throttle body communicating with an intake pipe of the internal combustion engine. an intake pressure sensor capable of detecting intake pressure in an intake pipe; an appropriate value determining means for determining whether a throttle opening detection value detected by the throttle opening sensor is normal or abnormal; Throttle opening determination means for comparing a throttle opening detected by a throttle opening sensor with a high load range setting value to determine whether a high load increase in fuel supply amount is necessary; and an intake pressure determined by the intake pressure sensor. a first intake pressure determining means that compares the detected value with a high load range setting value to determine whether a high load increase in fuel supply amount is necessary; and a throttle opening detected value is determined by the appropriate value determining means. When an abnormality is determined, the intake pressure detected by the intake pressure sensor is compared with a high load range setting value that is smaller than the normal high load range setting value to determine whether a high load increase in fuel supply amount is necessary. A fuel supply amount control device for an internal combustion engine, comprising a second intake pressure determining means for determining whether or not the intake pressure is high.