JPH01116265A - Fuel injection height correcting device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent air-fuel ratio from fluctuating due to a change of altitude by comparing an intake pressure with a reference pressure, set in the reference altitude, and correcting a fuel injection quantity being based on a difference between both the intake pressure and the reference pressure in the time of required opening of an intake throttle valve. CONSTITUTION:A control circuit 14 inputs in ignition signal from an ignition coil 22 in addition to detection values of an intake pressure sensor 16, intake throttle valve opening sensor 18, intake temperature sensor 20, etc., controlling the opening time of a fuel injection valve 12 to be calculated. The control circuit 14, which sets a reference intake pressure in a reference altitude corresponding to the required opening of an intake throttle valve 10, obtains an altitude being based on a difference between this reference intake pressure and the detection value of, the intake pressure sensor 16 corresponding to the same intake throttle valve opening, correcting the opening time of the fuel injection valve 12.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fuel injection altitude correction device for an internal combustion engine, and in particular, it is capable of correcting the amount of fuel injected and supplied to the internal combustion engine according to changes in altitude, and maintains an appropriate air-fuel ratio. The present invention relates to a fuel injection altitude correction device for an internal combustion engine that can achieve

[Conventional technology]

Devices that supply fuel to internal combustion engines include carburetors, fuel injection devices, and the like. The fuel injection system uses engine load, engine speed, cooling water temperature, intake air volume, intake air pressure, etc. as fuel injection amount setting factors, and sets the fuel injection amount supplied to the internal combustion engine according to the engine operating state. . For example, JP-A-58-13
The internal combustion engine disclosed in Japanese Patent No. 3433 uses a pressure sensor to detect the intake air pressure in the intake pipe as an absolute pressure when the internal combustion engine is operating, and sets the fuel injection amount.

The internal combustion engine disclosed in this publication is provided with a single pressure sensor, and corrects the absolute pressure in the intake pipe detected by the single pressure sensor during the period from power-on to the start of the internal combustion engine, that is, during the start of the internal combustion engine. This is stored in the control circuit as atmospheric pressure, which is a fuel injection amount setting factor. After the internal combustion engine is started, that is, while the internal combustion engine is running, the absolute pressure in the intake pipe detected by the single pressure sensor is used as the main fuel injection amount setting factor, and the fuel injection amount set by this main fuel injection amount setting factor is set. The fuel injection amount is corrected based on the atmospheric pressure, which is the stored fuel injection amount setting factor for correction, and the fuel injection amount is corrected in response to changes in atmospheric pressure.

[Problem that the invention seeks to solve]

Incidentally, the atmospheric pressure of air taken into an internal combustion engine varies depending on the altitude, and as the altitude increases, the atmospheric pressure decreases due to a decrease in air density. For this reason, internal combustion engines that set the fuel injection amount using the intake pressure as the main fuel injection amount setting factor and inject and supply fuel have the disadvantage that the air-fuel ratio becomes thinner as the altitude increases.

That is, as shown in Figure 4, altitude H and atmospheric pressure P are inversely proportional, and as altitude H increases, atmospheric pressure P decreases due to the decrease in air density.
decreases. In addition, as shown in Fig. 5, the opening degree θ of the intake throttle valve of the internal combustion engine and the intake pressure (absolute pressure) P in the intake passage
It is proportional to m, and as the opening degree θ of the intake throttle valve increases, the intake pressure Pm increases. However, even if the opening degree θ of the intake throttle valve is the same, as the altitude H increases, the atmospheric pressure P decreases. altitude H
At n, the intake pressure decreases to Pn.

In this way, when the fuel injection amount is set using the intake pressure Pm, which decreases as the altitude H increases, as the main fuel injection amount setting factor, as shown in FIG.
Even if they are the same, the required fuel injection time TAUo can be obtained by the intake pressure Po at the altitude Om, which is the reference altitude HO, but at a predetermined altitude H higher than this reference altitude Ho.
n, the intake pressure Pn is lower than the intake pressure Po.
Therefore, the fuel injection time TAUnL, which is shorter than the required fuel injection time TAUo, cannot be obtained. As a result, as shown in FIG. 7, as the altitude increases, the fuel injection time TAU becomes shorter, resulting in a disadvantage that the air-fuel ratio becomes thinner.

As a result, the air-fuel ratio becomes inappropriate, the output of the internal combustion engine decreases, the harmful components of the exhaust gas increase, and the fuel consumption rate worsens.

This problem of thinning of the air-fuel ratio due to the increase in altitude could not be solved by the internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 58-133433. What is disclosed in this publication is to store the absolute pressure in the intake pipe detected by a single pressure sensor during starting of the internal combustion engine as atmospheric pressure as a fuel injection amount setting factor for correction, and to The fuel injection amount, which is set using the intake pipe absolute pressure detected by the first pressure sensor as the main fuel injection amount setting factor, is corrected by the atmospheric pressure, which is the fuel injection amount setting factor for correction, and the fuel injection amount is adjusted to compensate for changes in atmospheric pressure. This corrects the injection amount. For this reason,
There is a problem in that the fuel injection amount cannot be corrected when the altitude during operation after starting the internal combustion engine is higher than the altitude during starting the internal combustion engine and the atmospheric pressure changes.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize a fuel injection altitude correction device for an internal combustion engine that can correct the amount of fuel injected and supplied to an internal combustion engine in accordance with changes in altitude and can optimize the air-fuel ratio.

[Means for solving problems]

In order to achieve this object, the present invention provides an intake pressure detection means for detecting the intake pressure of an internal combustion engine that injects and supplies fuel, and sets the intake pressure at a reference altitude corresponding to the required time state of the intake throttle valve of the internal combustion engine. To correct the amount of fuel injected and supplied to the internal combustion engine according to the difference between a reference intake pressure and a predetermined intake pressure detected by the intake pressure detection means at a predetermined altitude corresponding to the required opening state of the intake throttle valve of the internal combustion engine. It is characterized by providing a control means for controlling.

[Effect]

According to the configuration of the present invention, the control means controls the reference intake pressure set at the reference altitude corresponding to the required opening state of the intake throttle valve of the internal combustion engine, and the predetermined standard intake pressure set corresponding to the required opening state of the intake throttle valve of the internal combustion engine. By controlling the amount of fuel injected and supplied to the internal combustion engine to be corrected according to the difference between the intake pressure and the predetermined intake pressure detected by the intake pressure detection means at altitude, the amount of fuel injected and supplied to the internal combustion engine is corrected in accordance with changes in altitude. . This achieves optimization of the air-fuel ratio.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

1 to 3 show embodiments of this invention. In Figures 1 and 2, 2 is an internal combustion engine that injects and supplies fuel;
4 is an intake passage, 6 is a combustion chamber, 8 is an exhaust passage, 10 is an intake throttle valve, 12 is a fuel injection valve, and 14 is a control circuit as a control means.

The operation of the fuel injection valve 12 , which is attached to the intake passage 4 and directed toward the combustion chamber 6 of the internal combustion engine 2 , is controlled by a control circuit 14 . The control circuit 14 includes a pressure sensor 16 serving as an intake pressure control means for detecting the intake pressure in the intake passage 4, an opening sensor 18 for detecting the opening state of the intake throttle valve 10, and an opening sensor 18 for detecting the intake air temperature in the intake passage 4. An ignition coil 2 is connected to a temperature sensor 20 to input an ignition signal for setting injection timing.
2 is connected. Further, although not shown, other sensors 24 such as a cooling water temperature sensor and an 02 sensor are connected to the control circuit 14. These various sensors 1
The control circuit 14 controls the operation of the fuel injection valve 12 based on the signals input from the internal combustion engine 2 to inject fuel to the internal combustion engine 2 . For example, the intake pressure Pm detected by the pressure sensor 16
is the main fuel injection amount setting factor, and each detection signal of the opening sensor 18, temperature sensor 20, and other sensors 24 is used as the fuel injection amount setting factor for correction to set the fuel injection time TAU, and the ignition coil 22 is ignited. The operation of the fuel injection valve 12 is controlled according to the fuel injection time TAU in order to inject the fuel at the injection timing set by the signal.

As shown in FIG. 5, the intake pressure Pm detected by the pressure sensor 16 varies even if the opening degree of the intake throttle valve 10 is the same.
When the altitude changes from Om, which is the reference altitude HO, to the predetermined altitude Hn, the intake pressure PO decreases to the intake pressure Pn. In this way, as the intake pressure Pm decreases from Po to Pn, as shown in FIG. 6, at the altitude Om which is the reference altitude HO, the required fuel injection time TAU
.

However, at a predetermined altitude Hn higher than this reference altitude HO, the intake pressure P is lower than the intake pressure PO.
Because of n, it is not possible to obtain a fuel injection time TAUnL shorter than the required fuel injection time TAUo. As a result, as shown in FIG. 7, as the altitude increases, the fuel injection time TAU becomes shorter, resulting in a disadvantage that the air-fuel ratio becomes thinner.

As a result, the air-fuel ratio becomes inappropriate, the output of the internal combustion engine decreases, the harmful components of the exhaust gas increase, and the fuel consumption rate worsens.

In order to prevent such inconvenience, in the present invention, the control circuit 14 controls the required opening state θ of the intake throttle valve 10.
The reference intake pressure PO at the reference altitude HO is set corresponding to the required opening state θ of the intake throttle valve 10, and the reference intake pressure Po set at the reference altitude HO corresponding to the required opening state θ of the intake throttle valve 10 and the required opening of the intake throttle valve 10 are set. A predetermined altitude Hn corresponding to the state θ
Control is performed to correct the amount of fuel injected and supplied to the internal combustion engine 2 according to the difference from the predetermined intake pressure Pn detected by the pressure sensor 16.

Next, the operation will be explained according to FIG.

Control starts (100) L, internal combustion engine 2 starts (10
1) Then, fuel injection is started (102). The control circuit 14 detects (103) the opening degree θ of the intake throttle valve 10 and the intake pressure Pm of the intake passage 4 based on the signals inputted from the pressure sensor 16 and the opening sensor 18. The difference (Po-Pn) between Po and the predetermined intake pressure Pn detected by the pressure sensor 16 is calculated (104)L, and a correction value is calculated (105). With this correction value, the internal combustion engine 2
Fuel is injected (106). Next, it is determined whether or not the internal combustion engine 2 is starting (107) L. If it is still starting, the process jumps to step 10.3, and steps 103 to 1 are performed.
Execute 06. If the start is complete, end (10B
). In the control after the start is completed, as described above, θ and Pm are detected, the difference between them is calculated, a correction value is calculated, and fuel is injected into the internal combustion engine 2 based on the correction value. .

That is, the fuel injection time TAU is set at the altitude Om, which is the reference altitude Ho. A reference intake pressure PO is set corresponding to each opening degree of the intake throttle valve IO at this reference altitude HO. The reference intake pressure corresponding to the opening degree θ of the intake throttle valve 10 at this time is defined as the PO1 fuel injection time TAUo.

When the altitude increases from the reference altitude HO to the predetermined altitude Hn, the intake pressure corresponding to the opening degree θ of the intake throttle valve 10 becomes P as shown in FIG.
n, and the fuel injection time becomes TAUn. At this predetermined altitude Hn, the fuel injection time TAUo at the reference altitude Ho and the fuel injection time TA at the predetermined altitude Hn
There is a disadvantage that the fuel injection time corresponding to the difference from Un (TAUo-TAUn) is insufficient, and the air-fuel ratio becomes lean.

Therefore, the corrected fuel injection time T
AUH, and determine k that satisfies TAUH=TAUoX (1+k (Po-Pn)).

Here, the reason why TAUH is not set as TAUo is that the air density and atmospheric temperature change due to changes in altitude, so these are corrected using the constant k. Therefore, the opening degree θ of the intake throttle valve 10 detected by the opening sensor 18 is equal to the reference intake pressure Po and the predetermined altitude Hn detected by the pressure sensor 16.
From the relationship with the predetermined intake pressure Pn in (Po−Pn
) = 0, the reference altitude Ho is the altitude Qm, so
k-,0.

In this way, the control circuit 14 corrects the fuel injection time TAU based on the relationship between the opening θ of the intake throttle valve 10 detected by the opening sensor 18 and the reference intake pressure Po and the predetermined intake pressure Pn detected by the pressure sensor 16. By doing so, it is possible to increase the injection time at high altitudes, prevent the air-fuel ratio from becoming thinner, and optimize the air-fuel ratio.

Therefore, the output of the internal combustion engine 2 can be improved, the harmful components of exhaust gas can be reduced, and the fuel consumption rate can be improved.

〔Effect of the invention〕

As described above, according to the present invention, the control means corresponds to the reference intake pressure set at the reference altitude corresponding to the required opening state of the intake throttle valve of the internal combustion engine and the required opening state of the intake throttle valve of the internal combustion engine. By controlling to correct the amount of fuel injected and supplied to the internal combustion engine according to the difference between the intake pressure and the predetermined intake pressure detected by the intake pressure detection means at a predetermined altitude,
The amount of fuel injected and supplied to the internal combustion engine can be corrected according to altitude changes.

Thereby, the air-fuel ratio can be optimized, the output of the internal combustion engine can be improved, harmful components of exhaust gas can be reduced, and the fuel consumption rate can be improved.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of a fuel injection altitude correction device for an internal combustion engine, FIG. 2 is a block diagram of a control means, and FIG. 3 is a flowchart of control. . Figures 4 to 7 are diagrams illustrating fluctuations in air-fuel ratio due to changes in altitude, and Figure 4 is a diagram showing the relationship between altitude and atmospheric pressure.
Figure 5 is a diagram showing the relationship between intake throttle valve opening and intake pressure;
FIG. 6 is a diagram showing the relationship between intake pressure and fuel injection time, and FIG. 7 is a diagram showing the relationship between altitude and air-fuel ratio. In the figure, 2 is an internal combustion engine, 4 is an intake passage, 8 is an exhaust passage, 10 is an intake throttle valve, 12 is a fuel injection valve, 14 is a control circuit, 16 is a pressure sensor, and 18 is an opening sensor. Patent Applicant Suzuki Motor Co., Ltd. Agent Patent Attorney Yoshi Saigo Practical Figure 1 Figure 2 Figure 3 Figure 6 Figure 7

Claims (1)

[Claims] An intake pressure detection means for detecting the intake pressure of an internal combustion engine to which fuel is injected and supplied is provided, and a reference intake pressure set at a reference altitude corresponding to the required opening state of the intake throttle valve of the internal combustion engine and the intake throttle valve of the internal combustion engine are provided. A control means is provided for controlling the amount of fuel injected and supplied to the internal combustion engine in accordance with the difference between the intake pressure detected by the intake pressure detection means at a predetermined altitude and the required opening state. Fuel injection altitude correction device for internal combustion engines.