JP2015175284A - Internal combustion engine fuel injection control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine fuel injection control system capable of easily detecting that a throttle valve is in a fully closed state without the need of complicated control that causes a sharp increase in production cost.SOLUTION: A short circuit 23 is provided between a power supply voltage input section 31 and a signal output section 32 of an intake air pressure sensor 18 so as to be able to short-circuit the input section 31 and the signal output section 32. A throttle switch 24 for short-circuiting the input section 31 and the signal output section 32 when a throttle valve 13 is in a fully closed state is provided on the short circuit 23.

Description

  The present invention relates to a fuel injection control system for an internal combustion engine.

  In a fuel injection system for an internal combustion engine, a control device receives engine operation information such as a pressure in an intake passage and an engine rotation speed, and the control device controls an amount of fuel injection at a fuel injection valve based on the information. In the control of the fuel injection valve by such a control device, it is necessary to control the fuel injection amount in accordance with the operation state of the internal combustion engine such as fuel cut even when the throttle valve completely closes the intake passage. For this reason, it is important to accurately detect that the throttle valve is fully closed.

As a fuel injection system to cope with this, a throttle opening sensor that detects the opening of the throttle valve is provided, and the minimum detected value (minimum opening) by the throttle opening sensor is constantly updated and stored. When the detected value is equal to the stored minimum detected value, it is known that the throttle valve is determined to be fully closed (see, for example, Patent Document 1).
In this fuel injection system, when the detected value of the throttle opening sensor is equal to the stored minimum detected value, it is determined that the throttle valve is in the fully closed state. Even when is changed, the fully closed state of the throttle valve can be accurately detected.

JP-A-8-42385

  However, in the conventional fuel injection system, the detection information of the throttle opening sensor is monitored, and the update of the minimum detection value of the throttle valve is compared with the detection value of the throttle opening sensor and the stored minimum detection value. Must always be done on the controller side. For this reason, control by the control device becomes complicated, and it is necessary to add a dedicated base for the processing to the control device. Therefore, in this case, there is a concern that the production cost of the entire system will rise.

  Therefore, the present invention is intended to provide a fuel injection control system for an internal combustion engine that can easily detect that the throttle valve is in a fully closed state without requiring complicated control that causes an increase in production cost. is there.

In order to solve the above problems, a fuel injection control system for an internal combustion engine according to the present invention injects fuel into an intake passage (9), and supplies fuel from the fuel injection valve (17). A control device (16) for controlling the injection amount, a throttle valve (13) for adjusting the amount of intake air flowing through the intake passage (9), and a voltage signal corresponding to the pressure in the intake passage (9) as a signal output unit In the fuel injection control system for an internal combustion engine provided with an intake pressure sensor (18) that outputs to the control device (16) from (32), the power supply voltage input section (31) and the intake pressure sensor (18) A short circuit (23) capable of short-circuiting the input unit (31) and the signal output unit (32) is provided between the signal output unit (32) and the short circuit (23). When the throttle valve (13) is fully closed It is characterized in that the input unit (31) and said signal output section (32) a throttle switch for short-circuiting the (24) is provided on.
Thus, under the condition that the throttle valve (13) is opened, the short circuit (23) is opened, and the power supply voltage input part (31) and the signal output part (32) of the intake pressure sensor (18) are It will be in the state which does not short-circuit. Therefore, a voltage signal corresponding to the pressure in the intake passage (9) is taken into the control device (16) from the signal output unit (32) of the intake pressure sensor (18). On the other hand, when the throttle valve (13) is in the fully closed state, the throttle switch (24) closes the short circuit (23), and the power supply voltage input section (31) and the signal output section of the intake pressure sensor (18) ( 32) is short-circuited. Thereby, the specific voltage signal which passed through the short circuit (23) is input into a control apparatus (16). As a result, it can be detected by the same base of the control device (16) that the throttle valve (13) is fully closed.

It is desirable that a resistor (28) is interposed in the short circuit (23).
In this case, when the throttle valve (13) is fully closed and the short circuit (23) is closed, the voltage value of the power supply voltage is decreased by the resistance (28) of the short circuit (23), and the decreased voltage Is output from the signal output section (32) of the intake pressure sensor (18). For this reason, the voltage signal output when the throttle valve (13) is in the fully closed state is the voltage of the resistor (28) rather than the voltage value output when the electrical path of the intake pressure sensor (18) is short-circuited. Lowers the descent. Therefore, it is possible to determine when the throttle valve (13) is in the fully closed state and when there is a short circuit failure.

The intake pressure sensor includes a failure determination unit (25) that determines whether or not there is a failure in the electrical path of the intake pressure sensor (18), and corresponds to the minimum intake pressure (P1) during normal operation of the internal combustion engine. The voltage value of the voltage signal of (18) is V1, and the voltage value of the voltage signal of the intake pressure sensor (18) corresponding to the maximum intake pressure (P2) during normal operation of the internal combustion engine is larger than V2 and V2, and the power supply voltage When the voltage value smaller than the voltage value of V3 is V3, the resistance value of the resistor (28) interposed in the short circuit (23) is the intake pressure when the short circuit (23) is closed. The voltage signal Vout of the sensor (18) is set to be in a range of V2 <Vout <V3, and the failure determination unit (25) determines that the voltage signal Vout of the intake pressure sensor (18) is V3 ≦ Vout. In the electric path of the intake pressure sensor (18) It may be determined that there is a fault failure.
In this case, when the voltage signal Vout of the intake pressure sensor (18) is in the range of V2 <Vout <V3, the control device (16) determines that the throttle valve (13) is in the fully closed state and the fuel injection valve (17 ) Is controlled. When the voltage signal Vout of the intake pressure sensor (18) is in the range of V3 ≦ Vout, the failure determination unit (25) determines that there is a short circuit failure in the electrical path of the intake pressure sensor (18). With the above configuration, it is possible to determine when the throttle valve (13) is in the fully closed state and when the electrical path is short-circuited.

Further, when the voltage value smaller than V1 is set to V0, the failure determination unit (25) determines that the intake pressure is lower when the voltage signal Vout of the intake pressure sensor (18) is in a range of Vout ≦ V0. It may be determined that there is a disconnection failure in the electrical path of the sensor (18).
As a result, it is possible to determine from the voltage signal Vout of the intake pressure sensor (18) when the throttle valve (13) is in the fully closed state, when the electrical path is short-circuited, and when there is a disconnection failure.

Further, a rotational speed sensor (19) for detecting an engine rotational speed of the internal combustion engine and outputting a detection signal to the control device (16), an intake pressure of the intake passage (9), an engine rotational speed of the internal combustion engine, An injection map (33) in which the fuel injection amount is determined based on the engine speed, a throttle fully-closed injection table (34) in which the fuel injection amount is determined based on the engine speed of the internal combustion engine, and the intake passage (9) Ignition map (36) in which the ignition timing of the ignition plug (8) is determined based on the intake pressure of the engine and the engine rotational speed of the internal combustion engine, and ignition timing of the ignition plug (8) based on the engine rotational speed of the internal combustion engine A throttle fully-closed ignition table (37), and when the throttle valve (13) is not fully closed, the control device (16) and the ignition map (33) and the ignition The fuel injection amount of the fuel injection valve (17) and the ignition timing of the spark plug (8) are controlled with reference to the top (36), and when the throttle valve (13) is fully closed, the throttle The fuel injection amount of the fuel injection valve (17) and the ignition timing of the spark plug (8) are controlled with reference to the fully closed injection table (34) and the throttle fully closed ignition table (37). Also good.
In this case, when the throttle valve (13) is in the fully closed state, the intake pressure sensor (18) cannot detect the pressure in the intake passage (9). At this time, the throttle fully closed injection table (34) and the throttle fully closed By referring to the closing ignition table (37), it is possible to appropriately control the fuel injection amount of the fuel injection valve (17) and the ignition timing of the ignition plug (8).

  According to the present invention, a short circuit is provided between the input portion of the power supply voltage and the signal output portion of the intake pressure sensor, and the input portion and the signal output are only provided in the short circuit when the throttle valve is fully closed. Since the throttle switch for short circuiting is provided, the throttle valve is fully closed without adding a special base to the control device, and the same control device for detecting the pressure in the intake passage Can be detected by the base. Therefore, according to the present invention, it is possible to easily detect that the throttle valve is in the fully closed state while eliminating the need for complicated control that causes an increase in production cost by eliminating the throttle opening sensor.

1 is a diagram showing an overall configuration of an internal combustion engine according to an embodiment of the present invention. It is a figure showing typically some fuel injection systems of one embodiment of this invention. It is a figure showing typically some fuel injection systems of one embodiment of this invention. It is a voltage signal-intake pressure characteristic figure of an intake pressure sensor of one embodiment of this invention. FIG. 2 is a fuel injection amount-engine speed correspondence diagram (throttle fully-closed injection table) employed in the fuel injection system of one embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an overall configuration of an internal combustion engine 1 mounted on a motorcycle. In the figure, reference numeral 2 denotes a piston slidably accommodated in the cylinder 3, and reference numeral 4 denotes a crankshaft connected to the piston 2 via a connecting rod 5. A cylinder head 6 is disposed above the cylinder 3, and a spark plug 8 is attached to the cylinder head 6 so as to face the combustion chamber 7. An intake passage 9 and an exhaust passage 10 are connected to the cylinder head 6. An intake valve 11 that opens and closes the intake passage 9 in conjunction with the rotation of the crankshaft 4 is attached to a connection portion of the cylinder head 6 with the intake passage 9. An exhaust valve 12 that opens and closes the exhaust passage 10 in conjunction with the rotation of the crankshaft 4 is attached to a connection portion between the cylinder head 6 and the exhaust passage 10.

  A throttle valve 13 for adjusting the amount of intake air flowing through the intake passage 9 is provided downstream of the air cleaner (not shown) of the intake passage 9. The throttle valve 13 is connected to a throttle operator 15 provided on the handle portion 14 of the motorcycle so as to be interlocked by a wire cable. In this embodiment, an example in which the throttle operator 15 and the throttle valve 13 are connected by a wire cable has been described. However, a detection sensor for detecting an operation amount is provided on the throttle operator 15 side, and the throttle valve A drive motor may be provided on the 13th side, and the drive motor may be driven based on the detection value of the detection sensor.

  A fuel injection valve 17 that injects fuel into the intake passage 9 under the control of the control device 16 is attached downstream of the throttle valve 13 in the intake passage 9. The control device 16 controls the flow rate and injection timing of fuel injected from the fuel injection valve 17 into the intake passage 9, the ignition timing of the spark plug 8, and the like. An intake pressure sensor 18 for detecting the pressure in the intake passage 9 is attached to a position downstream of the throttle valve 13 in the intake passage 9 and upstream of the fuel injection valve 17. A signal detected by the intake pressure sensor 18 is input to the control device 16. On the other hand, a crank angle sensor 19 (rotational speed sensor) for detecting the rotational position of the crankshaft 4 is attached to the crankshaft 4. The rotation angle signal detected by the crank angle sensor 19 is also used as a signal for grasping the engine rotation speed in the control device 16.

2 and 3 are diagrams schematically showing a part of the fuel injection system of the internal combustion engine 1. In these drawings, reference numeral 20 denotes a battery mounted on the vehicle, and reference numeral 21 denotes a throttle drum that rotates integrally with the throttle valve 13.
The intake pressure sensor 18 employed in the fuel injection system of this embodiment has a pressure-sensitive element whose resistance value changes according to the pressure in the intake passage 9. Further, the intake pressure sensor 18 is a voltage obtained by dropping the power supply voltage Vcc by the resistance of a pressure sensing element corresponding to the pressure in the intake passage 9 and the input unit 31 connected to the power supply voltage Vcc (for example, 5 V) of the battery 20. And a signal output unit 32 that outputs the signal Vout to the control device 16.

  Further, in the detection circuit of the intake pressure sensor 18, a short circuit 23 that can short-circuit the input unit 31 and the signal output unit 32 between the input unit 31 of the power supply voltage Vcc and the signal output unit 32 of the intake pressure sensor 18. Is provided. The short circuit 23 includes a throttle switch 24 that short-circuits the input unit 31 and the signal output unit 32 only when the throttle valve 13 is fully closed, and a resistor 28 having a predetermined resistance value. It has been. The throttle switch 24 is constituted by, for example, a normally open contact switch, and is pressed by an operation arm 21a of a throttle drum 21 that rotates integrally with the throttle valve 13 when the throttle valve 13 is fully closed. Yes. FIG. 2 shows the state of the short circuit 23 when the throttle valve 13 is open, and FIG. 3 shows the state of the short circuit 23 when the throttle valve 13 is fully closed. The form of the throttle switch 24 is not limited to that of this embodiment, and various forms can be adopted as long as the short circuit 23 is closed when the throttle valve 13 is fully closed. Further, the type of the throttle valve 13 is not limited to the illustrated rotary type, and may be a direct acting type.

  The control device 16 refers to different maps and tables when the throttle valve 13 is not fully closed and when the throttle valve 13 is fully closed, and determines the fuel injection amount of the fuel injection valve 17 and the spark plug 8. Control ignition timing. That is, when the throttle valve 13 is not fully closed, the control device 16 refers to the injection map 33 in which the fuel injection amount is determined based on the intake pressure of the intake passage 9 and the engine speed of the internal combustion engine 1. While controlling the fuel injection amount of the injection valve 17, the ignition timing of the spark plug 8 is determined with reference to the ignition map 36 in which the ignition timing is determined based on the intake pressure of the intake passage 9 and the engine speed of the internal combustion engine 1. Control. When the throttle valve 13 is in the fully closed state, the control device 16 refers to the throttle fully closed injection table 34 as shown in FIG. 5 in which the fuel injection amount is determined based only on the engine speed of the internal combustion engine 1. Then, the fuel injection amount of the fuel injection valve 17 is controlled, and the ignition timing of the ignition plug 8 is determined with reference to the throttle fully closed ignition table 37 whose ignition timing is determined based only on the engine speed of the internal combustion engine 1. Control.

  The control device 16 also includes a failure determination unit 25 that determines whether or not there is a failure in the electrical path of the intake pressure sensor 18. When the failure determination unit 25 determines that there is a failure in the electrical path, the control device 16 turns on the warning indicator lamp 30 on the display panel to notify the driver of the failure.

Here, FIG. 4 is a voltage signal-intake pressure characteristic diagram of the intake pressure sensor 18 of this embodiment. In the figure, P1 is the minimum intake pressure during normal operation of the internal combustion engine 1, and P2 is the maximum intake pressure during normal operation of the internal combustion engine 1.
The intake pressure sensor 18 has a value between a minimum voltage value V1 corresponding to the minimum intake pressure P1 and a maximum voltage value V2 corresponding to the maximum intake pressure P2 during normal operation except when the throttle valve 13 is in a fully closed state. The voltage signal Vout is output from the signal output unit 32 to the control device 16. Here, when V3 is set to a voltage value larger than the maximum voltage value V2 and smaller than the power supply voltage Vcc, the resistance value of the resistor 28 interposed in the short circuit 23 is determined by the voltage signal Vout of the intake pressure sensor 18 as follows: It is set to be in the range of V2 <Vout <V3. Therefore, when the short circuit 23 is closed by the throttle switch 24 and the input portion 31 of the power supply voltage Vcc and the signal output portion 32 of the intake pressure sensor 18 are short-circuited, the voltage signal Vout in the range of V2 <Vout <V3 is controlled. 16 is input. When receiving the voltage signal Vout, the control device 16 refers to the injection map 34 and the ignition map 36 to control the fuel injection amount of the fuel injection valve 17 and the ignition timing of the spark plug 8.

  On the other hand, when the short circuit 23 is not closed by the throttle switch 24 but a short circuit failure occurs in the electrical path of the intake pressure sensor 18, a voltage signal Vout larger than V3 is not transmitted through the resistor 28. 16 is input. At this time, the control device 16 determines that the electrical path has a short circuit failure by the failure determination unit 25 and turns on the warning indicator lamp 30.

  Further, when V0 is set to a voltage value smaller than the minimum voltage value V1, when the electrical path of the intake pressure sensor 18 is broken, a voltage signal Vout in the range of Vout ≦ V0 is input to the control device 16. . At this time, the control device 16 determines that the electrical path has a disconnection failure by the failure determination unit 25, and turns on the warning indicator lamp 30.

In the fuel injection control system according to this embodiment, a short circuit 23 is provided between the input part 31 of the power supply voltage Vcc and the signal output part 32 of the intake pressure sensor 18, and all of the throttle valve 13 is provided in the short circuit 23. Since the throttle switch 24 for short-circuiting the input unit 31 and the signal output unit 32 when provided is closed, it is detected that the throttle valve 13 is fully closed without adding a special base to the control device 16. can do. That is, in this fuel injection control system, it is possible to detect that the throttle valve 13 is fully closed by using the base of the control device 16 that handles the voltage signal Vout of the intake pressure sensor 18 as it is.
Therefore, in this fuel injection system, it is possible to easily detect that the throttle valve 13 is in a fully closed state while eliminating the need for complicated control that leads to an increase in production cost by eliminating the throttle opening sensor. it can.

  Further, in the fuel injection control system according to this embodiment, since the resistor 28 having a predetermined resistance value is interposed in the short circuit 23, the voltage value output when the throttle valve 13 is fully closed is absorbed. The voltage value is lower by the voltage drop of the resistor 28 than the voltage value output when the electrical path of the atmospheric pressure sensor 18 is short-circuited. Therefore, in this fuel injection control system, it is possible to easily determine when the throttle valve 13 is in the fully closed state and when there is a short circuit failure.

  Specifically, in this fuel injection control system, when the short circuit 23 is closed, the voltage value Vout of the intake pressure sensor 18 is V2 <Vout <when the short circuit 23 is closed. When the voltage signal Vout of the intake pressure sensor 18 is set to be in the range of V3 and V3 ≦ Vout, the failure determination unit 25 determines that there is a short-circuit failure in the electrical path of the intake pressure sensor 18. I am doing so. Therefore, in this fuel injection control system, it is possible to easily determine when the throttle valve 13 is in the fully closed state and when there is a short circuit failure based on the value of the voltage signal Vout.

  Further, in the fuel injection control system of this embodiment, when the voltage signal Vout is in the range of Vout ≦ V0, it is determined that there is a disconnection failure in the electric path of the intake pressure sensor 18. Therefore, in this fuel injection control system, not only when the throttle valve 13 is in the fully closed state and when there is a short-circuit failure, but also a disconnection failure can be easily determined based on the value of the voltage signal Vout. .

  Further, the fuel injection control system of this embodiment refers to the injection map 33 and the ignition map 36 using the intake pressure of the intake passage 9 and the engine speed of the internal combustion engine 1 as parameters when the throttle valve 13 is not fully closed. When the throttle valve 13 is in the fully closed state by controlling the fuel injection amount of the fuel injection valve 17 and the ignition timing of the spark plug 8, the throttle fully closed injection table using only the engine speed of the internal combustion engine 1 as a parameter. 34 and the throttle fully closed ignition table 37 are used to control the fuel injection amount of the fuel injection valve 17 and the ignition timing of the spark plug 8. For this reason, even when the throttle valve 13 in which the pressure of the intake passage 9 cannot be detected by the intake pressure sensor 18 is fully closed, the fuel injection amount of the fuel injection valve 17 and the ignition timing of the spark plug 8 are appropriately controlled. can do.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 8 ... Spark plug 9 ... Intake passage 13 ... Throttle valve 16 ... Control device 17 ... Fuel injection valve 18 ... Intake pressure sensor 19 ... Crank angle sensor (rotation speed sensor)
DESCRIPTION OF SYMBOLS 23 ... Short circuit 24 ... Throttle switch 25 ... Failure determination part 28 ... Resistance 31 ... Input part 32 ... Signal output part 33 ... Injection map 34 ... Throttle fully closed injection table 36 ... Ignition map 37 ... Throttle fully closed ignition table P1 ... Minimum intake pressure P2 ... Maximum intake pressure

Claims (5)

A fuel injection valve (17) for injecting fuel into the intake passage (9);
A control device (16) for controlling the fuel injection amount from the fuel injection valve (17);
A throttle valve (13) for adjusting the amount of intake air flowing through the intake passage (9);
An internal combustion engine fuel injection control system comprising: an intake pressure sensor (18) that outputs a voltage signal corresponding to a pressure in the intake passage (9) from a signal output unit to the control device (16);
The short circuit which can short-circuit the said input part (31) and the signal output part (32) between the input part (31) of the said power supply voltage, and the said signal output part (32) of the said intake pressure sensor (18) (23) is provided,
The short circuit (23) is provided with a throttle switch (24) for short-circuiting the input unit (31) and the signal output unit (32) when the throttle valve (13) is fully closed. A fuel injection control system for an internal combustion engine.   The fuel injection control system for an internal combustion engine according to claim 1, wherein a resistance (28) is interposed in the short circuit (23). A failure determination unit (25) for determining whether or not there is a failure in the electrical path of the intake pressure sensor (18);
The voltage value of the voltage signal of the intake pressure sensor (18) corresponding to the minimum intake pressure (P1) during normal operation of the internal combustion engine is V1, and the intake pressure corresponding to the maximum intake pressure (P2) during normal operation of the internal combustion engine. The resistance value of the resistor (28) interposed in the short circuit (23) when the voltage value of the voltage signal of the atmospheric pressure sensor (18) is V2 and the voltage value larger than V2 and smaller than the power supply voltage is V3. Is set such that when the short circuit (23) is closed, the voltage signal Vout of the intake pressure sensor (18) is in the range of V2 <Vout <V3,
The failure determination unit (25) determines that there is a short circuit failure in the electrical path of the intake pressure sensor (18) when the voltage signal Vout of the intake pressure sensor (18) satisfies V3 ≦ Vout. The fuel injection control system for an internal combustion engine according to claim 2.   When the voltage value smaller than V1 is set to V0, the failure determination unit (25) determines that the intake pressure sensor (25) has a voltage signal Vout of the intake pressure sensor (18) in a range of Vout ≦ V0. 18. The fuel injection control system for an internal combustion engine according to claim 3, wherein it is determined that there is a disconnection failure in the electrical path of 18). A rotation speed sensor (19) for detecting the engine rotation speed of the internal combustion engine and outputting the detection signal to the control device (16);
An injection map (33) in which the fuel injection amount is determined based on the intake pressure of the intake passage (9) and the engine rotational speed of the internal combustion engine;
A throttle fully-closed injection table (34) in which the fuel injection amount is determined based on the engine speed of the internal combustion engine;
An ignition map (36) in which the ignition timing of the spark plug (8) is determined based on the intake pressure of the intake passage (9) and the engine speed of the internal combustion engine;
A throttle fully-closed ignition table (37) in which the ignition timing of the ignition plug (8) is determined based on the engine speed of the internal combustion engine,
When the throttle valve (13) is not fully closed, the control device (16) refers to the injection map (33) and the ignition map (36) to determine the fuel injection amount of the fuel injection valve (17). The ignition timing of the spark plug (8) is controlled, and when the throttle valve (13) is in a fully closed state, the throttle fully closed injection table (34) and the throttle fully closed ignition table (37) are referred to. The fuel injection control of the internal combustion engine according to any one of claims 1 to 4, wherein a fuel injection amount of the fuel injection valve (17) and an ignition timing of the spark plug (8) are controlled. system.

Images