JPS623148A - Fuel injection control method - Google Patents

Abstract

PURPOSE:To prevent engine stall by increasing the intake air-flow passing through the side path detouring a throttle valve upon decision that the detection signal caused on malfunction of specific detecting means or disconnection of electric path is inadequate thus executing idle-up. CONSTITUTION:Specific detecting means or a pressure sensor 4 for detecting main fuel injection setting factor or the supply air pressure (intake tube pressure), various detecting means or a water temperature sensor 6, an intake air temperature sensor 8, a rotation sensor 10, an input switch 12, etc. are provided to feed the output signals to a control circuit 2. Upon decision that the voltage level of pressure sensor 4 is inadequate, the control circuit 2 will control the fuel injection valve 14 thus to control the fuel injection to setting level on the basis of other detection signal such as the engine rotation sensed through the rotation sensor 10. At the sametime, a gate valve 24 is opened to open the side path 22 thus to increase the supply air flow and to execute idle up.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel injection control method, and in particular, to a method for controlling fuel injection when a main fuel injection amount setting factor is detected, such as when a specific detection means malfunctions or when an electrical circuit is disconnected. The present invention relates to a fuel injection control method that can prevent engine drivability from being impaired and ensure running stability.

[Conventional technology] Electrically detects the operating status of an internal combustion engine and injects fuel
In the so-called electronically controlled fuel injection control method for controlling the fuel injection amount, the operating state of the internal combustion engine is detected by various detection means including at least one specific detection means that should detect the main fuel injection amount setting factor, and Inspection...

8 various detection signals input from the detection means 1-7 control
・ ] 0 where the fuel injection amount is controlled by the circuit For example,
The main fuel injection amount setting factor is determined by the specific detection means such as a pressure sensor or an air flow meter.
In addition to detecting the intake pipe pressure, which is the supply air pressure, or the intake air flow rate, which is the supply air flow rate, various detection means such as a rotation speed sensor and a throttle valve opening sensor are used to detect the engine rotation speed, which is a factor for setting the fuel injection amount. Detects the throttle valve opening and
The fuel injection amount is controlled by a control circuit based on various detection signals including the detection signal of the specific detection means. or,
A pressure sensor and a rotational speed sensor are provided as specific detection means to detect intake pipe pressure and engine rotational speed, which are the main fuel injection amount setting factors. Some control the amount of fuel injection.

[Problems to be Solved by the Invention] By the way, due to malfunction of the specific detection means that should detect the main fuel injection amount setting factor, for example, a pressure sensor, disconnection of the power supply or output electric circuit, etc., the control circuit may not function properly. If the detection signal is no longer input, control of the fuel injection amount will be impaired. Therefore, in such cases, conventionally, the fuel injection amount has been controlled to a predetermined value that is generally set depending only on the engine speed. Alternatively, as disclosed in Japanese Patent Application Laid-Open No. 60-43142, the air-fuel ratio is controlled by adjusting the opening of the throttle valve to a predetermined opening set based on the engine speed and the amount of fuel supplied per revolution. Ta.

However, in the former case, the fuel injection amount is uniquely determined by the engine speed, and in the latter case, the throttle valve opening, that is, the intake air flow rate, is uniquely determined by the engine speed and the fuel supply amount per revolution. The barrel intake air flow rate is determined. For this reason, when the accelerator pedal is depressed, etc., errors occur in the control of the fuel injection amount and intake air flow rate, respectively, compared to control when the detection signal from the pressure sensor serving as the specific detection means is appropriate. As a result, engine drivability is impaired, such as engine stalling due to an inappropriate air-fuel ratio, resulting in unstable running. - [Object of the Invention] Therefore, the object of the present invention is to detect the engine operating state by various detection means including at least one specific detection means for detecting the main fuel injection amount setting factor, and to receive input from these various detection means. In a fuel injection control method in which the amount of fuel injection is controlled by a control circuit based on various detection signals, engine drivability is prevented from being impaired in the event of malfunction of the specific detection means or electrical circuit disconnection, etc., and running stability is improved. The object of the present invention is to realize a fuel injection control method that can ensure reliable fuel injection control.

[Means for Solving the Problems] In order to achieve this object, the present invention detects the operating state of the internal combustion engine using various detection means including at least one specific detection means for detecting the main fuel injection amount setting factor. In a fuel injection control method in which the fuel injection amount is controlled by a control circuit based on various detection signals input from these various detection means, the detection signal input from the specific detection means to detect the main fuel injection amount setting factor is appropriate. If the judgment of this detection signal is appropriate, the fuel injection amount is controlled according to the internal combustion engine operating state based on the various detection signals including this detection signal, and the fuel injection amount is controlled according to the operating state of the internal combustion engine. If the determination is negative, the fuel injection amount should be controlled to a predetermined value that is set based on the remaining various detection signals other than this detection signal, and the intake air flow rate should be increased. It is characterized by communicating with a side passage provided by bypassing the valve part.

[Operation] According to the method of the present invention, when the detection signal input from the specific detection means is determined to be appropriate, the fuel injection amount is controlled based on various detection signals including this detection signal. On the other hand, if it is determined that the input detection signal is inappropriate due to malfunction of the specific detection means or electrical circuit disconnection, the fuel injection amount is controlled to a predetermined value set based on the remaining various detection signals, and the intake passage is A side passage that bypasses the throttle valve portion is communicated to increase the air supply flow rate and idle up. In this way, by increasing the idle when a specific detection means malfunctions or the electrical circuit is disconnected, engine stalling due to an inappropriate air-fuel ratio when stepping on the accelerator is avoided, and engine operability is prevented from being impaired. do.

[Example] Next, embodiments of the present invention will be described in detail based on the drawings.

1 to 4 show embodiments of this invention.

In FIG. 3, various detection means are connected to the input side of the control circuit 2. A pressure sensor 4 is connected to the input side of the control circuit 2 as a specific detection means for detecting the intake pipe pressure which is the supply air pressure which is the main fuel injection amount setting factor. Water temperature sensor 6 to detect;
An intake temperature sensor 8 that detects the intake air temperature, which is the supply air temperature in the intake passage; a rotation speed sensor 10 that detects the engine rotation speed;
Other input switches 11 and the like are connected.

The control circuit 2, which receives detection signals from various detection means including these specific detection means, controls the operation of the fuel injection valve 14 connected to the output side based on the various detection signals, thereby controlling the fuel injection amount.

This invention secures running stability by preventing engine operability from being impaired in the event of malfunction of the pressure sensor 4 serving as the specific detection means or disconnection of the power source or output electric line 16. It is. Therefore, as shown in FIG. 2, an electromagnetic opening/closing valve 24 is connected to the output side of the control circuit 2 for opening and closing a side passage 22 provided in a bypass of the throttle valve 20 portion of the intake passage 18.

Further, a warning lamp 26 is connected to the output side of the control circuit 2 as a warning means for issuing a warning when the pressure sensor 4 malfunctions or the electrical circuit 16 is disconnected.

In addition, in FIG. 3, the reference numeral 28 is an ignition switch.

The control circuit 2 performs control as shown in FIG. A voltage value is input as a detection signal from the pressure sensor 4, which is a specific detection means for detecting the above fuel injection amount setting factor. It is determined whether this voltage value is appropriate. The voltage value corresponds to the pressure value within the intake pipe, as shown in FIG. Therefore, if a voltage value corresponding to a pressure value is input, it is determined to be appropriate. If the voltage value does not correspond to the pressure value due to malfunction of the pressure sensor 4, or if the voltage value is not input due to disconnection of the electric line 16, a negative determination is made.

If the voltage value of the pressure sensor 4 is determined to be appropriate, that is, YES, various sensors 4 to 4 including the voltage value
Based on the detection signal from the engine 12, the fuel injection valve 14 is controlled to control the fuel injection amount according to the operating state of the internal combustion engine.

At this time, the on-off valve 24 is closed to block the side passage 22 to prevent the intake air flow rate, which is the supply air flow rate, from increasing unnecessarily. This makes the figure? To ensure drivability by appropriately supplying fuel to internal combustion engines (not shown) according to operating conditions.

If the determination of the voltage value of the pressure sensor 4 is negative, that is, NO, the fuel is adjusted to a predetermined value set based on the rotation speed, which is the detection signal of the rotation speed sensor 10, for example, the remaining various detection signals other than the voltage value. The operation of the fuel injection valve 14 is controlled to control the injection amount. At this time, the opening/closing valve 24 is opened to open the side passage, thereby increasing the intake air flow rate, which is the intake air flow rate, and idling up. In addition, the warning lamp 26
lights up or flashes.

In this way, since the idle is raised when the pressure sensor 4, which is a specific detection means, malfunctions or the electrical circuit is disconnected, engine stalling due to an inappropriate air-fuel ratio when stepping on the accelerator is avoided, and engine operability is impaired. It is possible to prevent the vehicle from being damaged, and to ensure driving safety. Also,
In this embodiment, since a warning means is provided, it is possible to easily search for a failure location.

In this embodiment, a pressure sensor is used as an example of at least one specific detection means that should detect the main fuel injection amount setting factor, but other detection methods such as an air flow meter or hot wire detection means can be similarly controlled. It can be done. Also,
When a pressure sensor and a rotation speed sensor are provided as specific detection means for detection, the same control can be performed when one of the specific detection means, for example, the pressure sensor malfunctions or the electrical circuit is disconnected.

[Effects of the Invention] As described above, according to the method of the present invention, if the input detection signal is not appropriate due to malfunction of the specific detection means that should detect the main fuel injection amount setting factor or disconnection of the electric circuit, this detection The fuel injection amount is controlled to a predetermined value set based on the remaining various detection signals other than the signal, and the intake air flow rate is increased to idle up. In this way, by increasing the idle when a specific detection means malfunctions or the electrical circuit is disconnected, engine stalling due to an inappropriate air-fuel ratio when stepping on the accelerator can be avoided, and engine drivability can be prevented. It is possible to prevent this and ensure running stability.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Figure 1 is a flowchart of control, Figure 2 is a schematic explanatory diagram of a side passage provided in the intake passage, and Figure 3 is fuel injection control for carrying out the method of this invention. FIG. 4, which is a circuit diagram of the apparatus, is a graph showing the relationship between pressure values and voltage values. In the figure, 2 is a control circuit, 4 is a pressure sensor, 6 is a water temperature sensor, 8 is an intake temperature sensor, 10 is a rotation speed sensor, 14
1 is a fuel injection valve, 16 is an electric circuit, 18 is an intake passage, 20 is a throttle valve, 22 is a side passage, and 24 is an on-off valve.

Claims (1)

[Claims] The operating state of the internal combustion engine is detected by various detection means including at least one specific detection means that should detect the main fuel injection amount setting factor, and the fuel injection amount is controlled by a control circuit based on various detection signals input from these various detection means. In the fuel injection control method, it is determined whether or not a detection signal inputted from the specific detection means to detect the main fuel injection amount setting factor is appropriate, and if the determination of the detection signal is appropriate, Controlling the fuel injection amount according to the internal combustion engine operating state based on the various detection signals including this detection signal,
If the determination of the detection signal is negative, the fuel injection amount is controlled to a predetermined value set based on the remaining various detection signals excluding this detection signal, and the intake air of the internal combustion engine is controlled to increase the intake air flow rate. A fuel injection control method characterized by connecting a side passage provided by bypassing a throttle valve portion of the passage.