JPH0868355A - Fuel injection amount control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To simplify the air bleeding mechanism and reduce the cost when there is a fuel-free location in the fuel passage. A fuel sensor 45 is provided in a fuel pipe 22 communicating with an injector 19. During normal operation, the central processing unit (CPU) 54 adjusts the fuel injection amount from the injector 19 so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. Further, when the CPU 54 starts the engine 1,
It is determined whether fuel is present in the vicinity of the fuel sensor 45. When fuel is not present, it is determined that air remains in the fuel pipe 22 or the like, and the injector 1
9 is forcibly controlled to open. Therefore, the air is pushed by the fuel and is discharged from the opened injector 19 without providing a dedicated pipe and an electromagnetic check valve. Further, when the air is sufficiently discharged, the normal valve opening control is switched to avoid the situation where the injector 19 is opened and released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for controlling an injection amount of fuel supplied from a fuel pump of an internal combustion engine to an injector by a valve opening operation of the injector.

[0002]

2. Description of the Related Art Conventionally, air remains in the fuel passage after the engine is assembled, after maintenance and disassembly, or after lack of gas. Therefore, when starting the engine thereafter, it is necessary to remove this air.

As such a technique, for example, the actual fairness 5-
The thing disclosed by the 19571 gazette is known. In this technique, an air bleed pipe from a fuel pump that pressure-feeds the fuel to the injector, and an electromagnetic check valve installed in the air bleed pipe are provided. Then, when the engine is assisted in starting (at the time of glow plug residual heat), the fuel pump and the electromagnetic check valve are energized to discharge the air in the fuel pipe. With this configuration,
It is possible to automatically bleed air and prevent fuel from leaking to the outside.

[0004]

However, in the above-mentioned prior art, a dedicated pipe and an electromagnetic check valve for exhausting air are required. Therefore, the mechanism is complicated and the cost is increased.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a fuel injection amount control device for controlling the injection amount of fuel by the valve opening operation of an injector, in which fuel is injected into a fuel passage. An object of the present invention is to provide a fuel injection amount control device for an internal combustion engine that can simplify the air bleeding mechanism and reduce the cost when there is a nonexistent portion.

[0006]

In order to achieve the above object, in the invention described in claim 1, as shown in FIG. 1, an intake passage M2 connected to an engine body M1 of an internal combustion engine.
And an injector M3 capable of injecting pressurized fuel to the engine body M1 from a tip end facing the intake passage M2 by a valve opening operation, and a fuel passage M5 connecting the injector M3 and the fuel tank M4. , A fuel pump M6 that sucks the fuel in the fuel tank M4 and pressure-feeds it to the injector M3, an operating state detection unit M7 that detects the operating state of the engine body M1, and a period during which the engine body M1 is driven. , The injector M3 at predetermined timings based on the detection result of the operating state detecting means M7.
The normal valve opening control means M8 for controlling the valve opening, the judgment means M9 capable of judging that there is a fuel-free area in at least a part of the fuel passage M5, and the judgment means M9 When it is determined that the fuel-free portion is present in at least a part of the passage M5, the fuel pump M6 is driven for a predetermined time until the fuel reaches the injector M3.
The gist is a fuel injection amount control device for an internal combustion engine including a forced valve opening control means M10 for forcibly opening the injector M3.

Further, in the invention described in claim 2,
The fuel injection amount control device for an internal combustion engine according to claim 1, wherein the determination means M9 is a fuel sensor that is capable of detecting the presence or absence of fuel provided in the injector M3 or the fuel passage M5 in the vicinity of the injector M3. Further, the gist of the forced valve opening control means M10 is to terminate the forced valve opening control of the injector M3 when the presence of fuel is determined by the fuel sensor.

[0008]

According to the invention described in claim 1, as shown in FIG. 1, the fuel connecting the injector M3 and the fuel tank M4 provided in the intake passage M2 connected to the engine body M1 of the internal combustion engine. Fuel pump M provided in passage M5
The fuel in the fuel tank M4 is sucked by 6 and sent under pressure to the injector M3. Further, by the valve opening operation of the injector M3, the pressurized fuel can be injected from the tip portion facing the intake passage M2 to the engine body M1. Then, the operating state detecting means M7 detects the operating state of the engine body M1. While the engine body M1 is driven, the normal valve opening control means M is based on the detection result of the operating state detection means M7.
8, the injector M3 is valve-opened at a predetermined timing.

Then, the fuel passage M is judged by the judging means M9.
It can be determined that there is a fuel-free location in at least part of 5. When the determination means M9 determines that there is a fuel-free portion in at least a part of the fuel passage M5, from when the fuel pump M6 is driven until the fuel reaches the injector M3. Forced valve opening control means M10 for the required predetermined time
Thus, the injector M3 is forcibly controlled to open.
Therefore, it is possible to bleed air without leaking fuel to the outside without providing a dedicated air bleeding pipe, electromagnetic check valve, or the like.

According to the second aspect of the present invention, in addition to the function of the first aspect, the determining means M9 is provided in the injector M3 or the fuel passage M5 in the vicinity of the injector M3. The fuel sensor can detect the presence or absence of fuel. When the presence of fuel is determined by the fuel sensor, the forced valve opening control means M10 ends the forced valve opening control of the injector M3. Therefore, the injector M3 is not opened and released even though the air is completely exhausted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
It will be described with reference to FIG. FIG. 2 shows a schematic configuration of a multi-cylinder gasoline engine (hereinafter, simply referred to as an engine) 1 as an internal combustion engine mounted on a vehicle, and peripheral devices thereof. The cylinder block 1a and the cylinder head 1b of the engine 1 form an engine body. In the cylinder block 1a, the same number of cylinder bores 2 as the number of cylinders are arranged side by side in a direction orthogonal to the paper surface, and a piston 3 is housed in each cylinder bore 2 so as to be vertically reciprocable. The piston 3 is connected to the crankshaft 5 by a connecting rod 4. Then, the reciprocating motion of the piston 3 is converted into a rotary motion by the connecting rod 4, and the crankshaft 5 is rotationally driven.

A combustion chamber 6 is formed above the piston 3, and an intake passage 7 and an exhaust passage 8 communicate therewith.
A communication portion between the combustion chamber 6 and the intake passage 7 is an intake port 9, and the intake port 9 is opened and closed by an intake valve 11 attached to the cylinder head 1b so as to be movable up and down. Further, a communication portion between the combustion chamber 6 and the exhaust passage 8 is an exhaust port 10, and the exhaust port 10 is attached to the cylinder head 1b so as to be vertically movable.
It is opened and closed by 2.

In the intake passage 7, an air cleaner 13, a throttle body 14, a surge tank 15, and an intake manifold 16 are arranged in this order from the upstream side toward the cylinder head 1b.
Are arranged, and the outside air is taken into the combustion chamber 6 via these. A throttle valve 17 is supported by a shaft 18 in the throttle body 14 so as to be integrally rotatable.
The shaft 18 is connected to an accelerator pedal (not shown) by a cable or the like. Then, when the driver depresses the accelerator pedal, the depressing operation is transmitted to the shaft 18 via a cable or the like, and the throttle valve 17 causes the shaft 1 to move.
It rotates together with 8. The rotation of the throttle valve 17 opens and closes the intake passage 7 to adjust the amount of intake air to the combustion chamber 6. The surge tank 15 is a tank for smoothing the pulsation of intake air and preventing intake interference of each cylinder. Note that, in FIG. 2, the intake manifold 16 is illustrated to be larger than other portions for convenience of description.

The intake manifold 16 is equipped with the same number of injectors 19 as the number of cylinders. A tip portion 19a of each injector 19 faces the intake passage 7, and fuel is injected from the tip portion 19a toward the intake port 9 of the corresponding cylinder.

The injector 19 is connected to one delivery pipe 21. The delivery pipe 21 is connected to the fuel tank 23 by a fuel pipe 22.
A fuel passage is formed by both pipes 21 and 22.
A fuel filter 24 and a pressure regulator 25 are provided in the middle of the fuel pipe 22, and a fuel pump 26 is connected to the tip of the fuel filter 24 in the fuel tank 23. The fuel in the fuel tank 23 is sucked and discharged by the operation of the fuel pump 26. Fuel pump 2
The fuel discharged from 6 is the pressure regulator 2
5, it is sent to the delivery pipe 21 by pressure through the fuel filter 24 and the fuel pipe 22. The pressure-fed fuel is distributed to each injector 19 by the delivery pipe 21, and is injected when the injector 19 opens. In addition,
The pressure regulator 25 is provided for each injector 1
It has a function of keeping the pressure of the fuel pumped to 9 at a constant pressure and returning excess fuel (return fuel) to the fuel tank 23.

A mixture of fuel injected from each injector 19 and outside air introduced into the intake passage 7 is introduced into the combustion chamber 6 through the intake port 9 when the intake valve 11 is opened. In order to ignite the air-fuel mixture introduced into the combustion chamber 6, a semiconductor ignition type ignition device is provided. This ignition device includes an ignition coil 28 and an igniter 29 that generate a high voltage by utilizing a transient phenomenon of an electric circuit, a distributor 31 that distributes the high voltage to each cylinder, and an ignition plug 32 that is a discharge unit. Has been done.

Then, the air-fuel mixture introduced into the combustion chamber 6 is burned by the ignition of the spark plug 32, and the piston 3,
The driving force of the engine 1 can be obtained via the connecting rod 4, the crankshaft 5, and the like. In this way, the combustion chamber 6
The burned gas (exhaust gas) that has been burned in (1) is led out from the exhaust port 10 to the exhaust passage 8 when the exhaust valve 12 is opened.

In the exhaust passage 8, an exhaust manifold 33 and a catalytic converter 34 are arranged in this order from the cylinder head 1b toward the downstream side, through which exhaust gas is exhausted to the outside. The catalytic converter 34 is a device that purifies hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxide (NOx) in the exhaust gas by the action of the catalyst 35.

In order to detect the operating state of the engine 1, an air flow meter 46, an intake air temperature sensor 47, a throttle sensor 48, a water temperature sensor 49, an oxygen sensor 50, a rotation speed sensor 51, a crank angle sensor 52, etc. are provided. There is. These components constitute an operating state detecting means. The air flow meter 46 is an air flow meter that measures the amount of air taken in by the engine 1, and the intake air temperature sensor 47 is mounted in the air flow meter 46 and flows through the intake passage 7 due to a change in the resistance value of a built-in thermistor. The change in intake air temperature (intake air temperature) is detected.

The throttle sensor 48 is attached to the throttle body 14 and detects the opening of the throttle valve 17 (throttle opening). The water temperature sensor 49 is attached to the water outlet and detects the temperature of the cooling water of the engine 1 (cooling water temperature). More specifically, like the intake air temperature sensor 47, the water temperature sensor 49 is composed of a thermistor whose resistance value greatly changes with temperature, and detects a change in cooling water temperature by a change in resistance value. The cooling water temperature corresponds to the temperatures of the cylinder block 1a and the cylinder head 1b.

The oxygen sensor 50 is attached to the exhaust manifold 43 and detects the oxygen concentration in the exhaust gas. The oxygen sensor 50 has a characteristic that the output voltage changes rapidly near the stoichiometric air-fuel ratio.

Rotation speed sensor 51 and crank angle sensor 5
Both 2 are built in the distributor 41.
The rotation speed sensor 51 is composed of one timing rotor having a large number (for example, 24) of protrusions on its outer circumference and one pickup coil. This rotation speed sensor 5
In No. 1, when the timing rotor makes one revolution, the pickup coil generates the same number of pulse signals as the protrusions at each equal crank angle (for example, 30 °). The crank angle sensor 52 is composed of one timing rotor having one protrusion on the outer circumference and two pickup coils. In this crank angle sensor 52, when the timing rotor makes one revolution, each pickup coil alternately generates one pulse signal at every crank angle of 360 °.

Further, in this embodiment, a fuel sensor 45 constituting a judging means is provided in the fuel pipe 22 immediately before the delivery pipe 21. If the fuel sensor 45 is, for example, a thermistor used for warning of the remaining fuel amount, a float sensor, or the like, the current is turned on / off or the voltage (resistance) value is changed depending on the presence or absence of fuel. Any sensor may be used. That is, the fuel sensor 45 determines the presence or absence of fuel in the vicinity of the injector 19 (whether the fuel pipe 22 is full of fuel or air is present), and the presence or absence of fuel at that time. Is output (fuel signal).

The air flow meter 46 and various sensors 4
5, 47 to 52 are electrically connected to the input side of an electronic control unit (hereinafter referred to as “ECU”) 53. Further, the injectors 19 and the igniter 39 are connected to the ECU 53.
Is electrically connected to the output side of.

As shown in FIG. 3, the ECU 53 includes a central processing unit (hereinafter referred to as CPU) 54 as a normal valve opening control means and a forced valve opening control means, a read-only memory (hereinafter referred to as ROM) 55, and a random access memory ( Below R
AM) 56, a backup RAM 57, an external input circuit 58, and an external output circuit 59, which are connected to each other by a bus 60. The CPU 54 executes various arithmetic processes according to a preset control program, and the ROM 55 stores in advance control programs and initial data necessary for the CPU 54 to execute arithmetic processes. The RAM 56 temporarily stores the calculation result of the CPU 54, and the backup RAM 57 is backed up by a battery so as to retain various data even after the power is turned off. The external input circuit 58 has an A / D converter (analog / digital converter). For example, the intake air temperature signal from the intake air temperature sensor 47, the water temperature sensor 4
An analog signal such as the cooling water temperature signal by 9 is converted into a digital signal.

Various signals from the air flow meter 46, the intake air temperature sensor 47, the throttle sensor 48, the water temperature sensor 49, the oxygen sensor 50, the rotation speed sensor 51, the crank angle sensor 52 and the fuel sensor 45 are input to an external input circuit 58. It The CPU 54 detects the intake air amount, intake air temperature, throttle opening, cooling water temperature, oxygen concentration, engine speed, crank angle signal, fuel signal, etc. based on these signals.

On the other hand, during normal operation, the CPU 54 sets the air-fuel ratio (air in the air-fuel mixture sucked into the engine 1 /
The fuel weight ratio) A / F is detected from the output signal of the oxygen sensor 50, and the fuel injection amount from the injector 19 is adjusted so that the air-fuel ratio A / F becomes the stoichiometric air-fuel ratio. In order to adjust the fuel injection amount, the CPU 54 calculates the target fuel injection time which is the valve opening time of the injector 19 based on a predetermined calculation formula. Then, after calculating the target fuel injection time, the CPU 54 outputs a drive signal corresponding thereto to the injector 19 via the external output circuit 59. The output of this signal controls the valve opening time of the injector 19 to inject a predetermined amount of fuel. In this way, feedback control is performed so that the air-fuel ratio A / F becomes the stoichiometric air-fuel ratio (normal valve opening control).

Next, the operation and effect of this embodiment constructed as described above will be described. The flowchart of FIG. 4 shows a “start-up injector control routine” for controlling the injector 19 when the engine 1 is started, among the processes executed by the CPU 54.
This routine is executed at every predetermined timing after the ignition key is set to the starting position and the rotation of the crankshaft 5 by the starter is started.

When the routine of FIG. 4 is started, the CPU 5
First, in step 101, 4 reads a detection signal based on the detection results from the air flow meter 46 and various sensors 45, 47 to 52, and the like. These detection signals include
A fuel signal from the fuel sensor 45 is also included.

Next, in step 102, the CPU 54 determines whether or not fuel is present in the vicinity of the fuel sensor 45 based on the fuel signal read by the fuel sensor 45 this time. Then, when it is determined that the fuel does not exist near the fuel sensor 45 at present, the CPU 54 determines that the air needs to be deflated, and step 1
In 03, the injector 19 is opened. At this time, all the injectors 19 may be opened, or only a specific injector 19 may be opened. Then, the CPU 54 once ends the subsequent processing.

On the other hand, when it is determined in step 102 that fuel is present in the vicinity of the fuel sensor 45, the CPU 54 determines that it is not necessary to bleed the air, and in step 104, the normal operation described above is performed. The injector control (normal valve opening control) is executed, and the subsequent processing is temporarily ended. As described above, in the "start-up injector control routine", the injector 19 is appropriately controlled according to the presence or absence of fuel.

As described above, according to this embodiment,
At the time of starting the engine 1, it is determined whether or not fuel is present in the vicinity of the fuel sensor 45. If no fuel is present, it means that the engine is currently installed immediately, immediately after maintenance and disassembly, or immediately after running out of gas. , Delivery pipe 2
1 or the air is judged to remain in the fuel pipe 22. Then, in such a case, as shown in FIG. 5, the injector 19 is forcibly controlled to open. Therefore, the air existing in the delivery pipe 21 or the fuel pipe 22 is pushed by the fuel and is discharged from the tip end portion 19a of the injector 19 that is open. Therefore, the air can be reliably discharged without providing a dedicated pipe and an electromagnetic check valve for discharging the air in the fuel. As a result, the mechanism can be simplified and the cost can be significantly reduced.

At this time, the air is discharged into the intake port 9. Therefore, even if the fuel is discharged together with the air due to the forced opening of the valve, it is possible to reliably prevent the fuel from leaking to the outside.

Further, in this embodiment, when the fuel reaches the position of the fuel sensor 45, the delivery pipe 2
1 or the air in the fuel pipe 22 is sufficiently discharged, and it is determined that the fuel is full. Then, as shown in FIG. 5, the valve opening control of the injector 19 is switched from the forced valve opening control until then to the normal valve opening control. That is, the fuel injection control is executed almost regularly based on the crank angle signal from the crank angle sensor 52. Therefore, it is possible to avoid the situation where the injector 19 is opened and released even though the air is completely exhausted. As a result, it is possible to prevent fuel from leaking due to continuous valve opening, and thus to prevent fuel from accumulating on the spark plug 32 or the like, and preventing the accumulated fuel from smoking. You can

The present invention is not limited to the above embodiment, but may be configured as follows, for example. (1) In the above embodiment, the fuel sensor 45 is connected to the fuel pipe 2
Although it is configured to be provided in No. 2, it may be provided in the delivery pipe 21 or may be provided directly in the injector 19.

(2) In the above embodiment, the fuel sensor 45 detects the presence or absence of fuel, but the sensor may be omitted. For example, when the engine 1 is started after being assembled, at least once,
The forced valve opening control may be executed as in this embodiment for a predetermined time that is empirically determined in advance. In addition, a separate switch is provided so that it can be recognized after maintenance and disassembly or after running out of gas based on the operation of turning on the switch. When the switch is turned on, it is empirically determined beforehand. The forced valve opening control may be executed for a predetermined time.

That is, if there is some means capable of determining that fuel is not present in the fuel pipe 22 or the like, the fuel sensor 45 or the like may not be provided. (3) In the above-described embodiment, the pressure regulator 25 is provided in the fuel tank 23. However, the pressure regulator 25 is provided in the middle of the delivery pipe 21 or the fuel pipe 22, and excess fuel is supplied to the fuel tank in the return passage. The configuration may be such that it can be returned to 23.

(4) The injection method by the valve opening control of the injector 19 in the normal valve opening control may be group injection or independent injection. (5) In the above-described embodiment, the embodiment is applied to the gasoline engine, but may be applied to the diesel engine.

[0039]

As described in detail above, according to the present invention,
In a fuel injection amount control device that controls the fuel injection amount by the valve opening operation of an injector, it is possible to simplify the air bleeding mechanism and reduce the cost when there is a portion where fuel does not exist in the fuel passage. It has an excellent effect.

In particular, according to the second aspect of the invention, it is possible to prevent the fuel from leaking due to the continuous valve opening, and to prevent the accumulated fuel from being smoked. it can.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing a fuel injection amount control device for an internal combustion engine in one embodiment embodying the present invention.

FIG. 3 is a block diagram showing an electrical configuration of an ECU in one embodiment.

FIG. 4 is a flowchart showing a “start-up injector control routine” executed by a CPU in one embodiment.

FIG. 5 is a timing chart for explaining the valve opening state of the injector with respect to time in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 1a ... Cylinder block which comprises an engine body, 1b ... Cylinder head which constitutes an engine body, 7 ... Intake passage, 19 ... Injector, 21
... delivery pipe forming a fuel passage, 22 ... fuel pipe forming a fuel passage, 23 ... fuel tank, 26 ... fuel pump, 45 ... fuel sensor as judging means, 46 ... air flow meter constituting operating state detecting means, 47 ... Intake temperature sensor constituting operating state detecting means, 48 ... Throttle sensor constituting operating state detecting means, 49 ... Water temperature sensor constituting operating state detecting means, 50 ... Oxygen sensor constituting operating state detecting means, 51 ... a rotation speed sensor that constitutes the operating state detecting means, 52 ... a crank angle sensor that constitutes the operating state detecting means, 54 ... a CPU that constitutes the normal valve opening control means and the forced valve opening control means.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area F02M 69/00

Claims (2)

[Claims] 1. An injector provided in an intake passage connected to an engine body of an internal combustion engine, capable of injecting pressurized fuel to the engine body from a tip end facing the intake passage by a valve opening operation; A fuel pump that is provided in a fuel passage that connects a fuel tank, sucks the fuel in the fuel tank, and pressure-feeds the fuel to the injector; an operating state detection unit that detects an operating state of the engine body; During normal operation, there is a normal valve opening control means for controlling the valve opening of the injector at every predetermined timing based on the detection result of the operating state detection means, and a portion where fuel does not exist in at least a part of the fuel passage. That the fuel is absent in at least a part of the fuel passage. In this case, a forced valve opening control means for forcibly controlling the valve opening of the injector is provided for a predetermined time required from the time when the fuel pump is driven until the fuel reaches the injector. A fuel injection amount control device for an internal combustion engine. 2. The determination means is composed of a fuel sensor which is provided near the injector in the injector or the fuel passage and can detect the presence or absence of fuel,
2. The fuel injection for an internal combustion engine according to claim 1, wherein the forced valve opening control means ends the forced valve opening control of the injector when the presence of fuel is determined by the fuel sensor. Quantity control device.