JP2001108556A - Pressure sensor for internal combustion engine and pressure signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable one internal combustion engine pressure sensor disposed on the cylinder head of an internal combustion engine to simultaneously sense combustion pressure and detect abnormalities in a fuel injection system to thereby simplify an arrangement about the cylinder head, relating to the pressure sensor and a pressure signal processor for processing pressure signals output from the internal combustion engine pressure sensor. SOLUTION: A pressure sensor 30 is disposed integrally with an injector 10 mounted on a cylinder head 12 while facing a combustion chamber 13 in an internal combustion engine 11, and pressure within the combustion chamber 13 and vibration resulting from the injection of fuel from the injector 10 are sensed by the pressure sensor 30, which in turn outputs pressure signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor and a pressure signal processing device for an internal combustion engine, and more particularly to a pressure sensor for an internal combustion engine disposed on a cylinder head of the internal combustion engine and a signal output from the pressure sensor for the internal combustion engine. The present invention relates to a pressure signal processing device for processing a pressure signal.

[0002]

2. Description of the Related Art As is well known, in an internal combustion engine (hereinafter referred to as an engine) with advanced ignition timing or a higher compression ratio, and an engine equipped with a supercharger, the compression pressure increases near the full load. Knocking easily occurs. In knock control that suppresses the occurrence of knocking, knocking that occurs in the engine is detected by detecting engine vibration and by detecting combustion pressure in the combustion chamber, and if detected, retards the ignition timing. By doing so, the occurrence of knocking is suppressed.

Therefore, in order to perform knock control,
It is necessary to provide a knock sensor or a combustion pressure sensor in the engine. In particular, when a combustion pressure sensor is provided in an engine, since the combustion pressure sensor directly measures the pressure in the combustion chamber, it must be provided on the cylinder head so as to face the combustion chamber. However, in recent years, it has been desired to improve the fuel efficiency, the output, and the emission of the engine, and the engine tends to be multi-valve in order to cope with the demand. Along with this, it is necessary to arrange a large number of intake and exhaust valves in the cylinder head, and a cam mechanism for driving each valve is complicatedly arranged above the intake and exhaust valves. For this reason, in the configuration in which the combustion pressure sensor is disposed alone on the cylinder head, it is necessary to provide a mounting hole in the cylinder head, and thus the arrangement position of other components disposed around the cylinder head is limited by this. Receive.

To solve this problem, a spark plug incorporating a combustion pressure sensor has been proposed (JP-A-6-140125). According to the technique disclosed in the publication, since the combustion pressure sensor is integrated into the spark plug, it is not necessary to provide a mounting hole for the combustion pressure sensor in the cylinder head, and the combustion pressure sensor is disposed around the cylinder head. It is possible to ensure the degree of freedom of the arrangement position of other components.

[0005]

The internal combustion engine is provided with various diagnostic devices (diagnosis) in order to improve safety, and one of them is a diagnosis relating to an injector. In the diagnosis of this injector, the operation of the injector is checked,
The normality of the fuel injection state is diagnosed. Specifically, the injector is provided with a sensor capable of detecting the presence or absence of operation and the fuel injection state, and the injector is diagnosed based on the output signal of the sensor.

Conventionally, however, the combustion pressure sensor is built in the spark plug as described above, so that the cylinder head can be made compact around the cylinder head to some extent. However, a sensor for diagnosis of the injector is separately provided in the cylinder head. Needed. For this reason, it is not possible to sufficiently reduce the size around the cylinder head, and the arrangement position of other components also arranged around the cylinder head is limited by the diagnosis sensor of the injector. There was a point.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and by arranging a pressure sensor for an internal combustion engine in a fuel injection device, the detection of the combustion pressure and the fuel injection device can be performed with one pressure sensor for the internal combustion engine. It is an object of the present invention to provide a pressure sensor and a pressure signal processing device for an internal combustion engine, which are capable of detecting an abnormality of the internal combustion engine, thereby simplifying the configuration around the cylinder head.

[0008]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by taking the following means. The pressure sensor for an internal combustion engine according to the first aspect of the present invention is characterized by being integrally provided with a fuel injection device attached to a main body of the internal combustion engine.

According to the first aspect of the present invention, since the pressure sensor for the internal combustion engine is integrally attached to the fuel injection device, the pressure sensor is generated when the fuel injection device injects fuel by the pressure sensor for the internal combustion engine. Vibration can be detected. Thus, by being able to detect the operating state of the fuel injection device, it is possible to determine whether the fuel injection device is operating normally based on the pressure oscillation output from the internal combustion engine pressure sensor.

The pressure sensor for an internal combustion engine according to the second aspect of the present invention is configured so as to be integrally provided in a fuel injection device mounted on a main body of the internal combustion engine so as to face a combustion space, A pressure signal is output by detecting a pressure in the combustion space and a vibration accompanying the fuel injection of the fuel injection device.

According to the second aspect of the present invention, the pressure sensor for the internal combustion engine is provided integrally with the fuel injection device attached to the main body of the internal combustion engine so as to face the combustion space. With the use pressure sensor, it is possible to detect both the vibration generated when the fuel injection device injects the fuel and the combustion pressure in the combustion space (combustion chamber).
As described above, since the state of two internal combustion engines can be detected by one internal combustion engine pressure sensor, the configuration around the cylinder head can be simplified.

According to a third aspect of the present invention, there is provided a pressure signal processing device having pressure signal processing means for processing a pressure signal output by the internal combustion engine pressure sensor according to the second aspect, The processing means is characterized in that a vibration signal component accompanying the injection of the fuel injection device is extracted from the pressure signal output by the internal combustion engine pressure sensor.

According to the third aspect of the present invention, the vibration signal component accompanying the injection of the fuel injection device is extracted from the pressure signal output from the pressure sensor for the internal combustion engine by the pressure signal processing means. The components can be used separately. According to a fourth aspect of the present invention, in the pressure signal processing device according to the third aspect, further based on the vibration signal component extracted by the pressure signal processing means,
A fuel injection device abnormality determining means for performing abnormality determination of the fuel injection device is provided.

According to the fourth aspect of the present invention, the abnormality determination of the fuel injection device can be performed by the fuel injection device abnormality determination means. That is, the vibration signal component of the fuel injection device extracted by the pressure signal processing means is a signal reflecting the state of the fuel injection device. If the vibration signal component is not extracted when the command signal for injection to the fuel injection device is output, it can be determined that the fuel injection device is not operating. In addition, even if the vibration signal component is extracted, if the amplitude of the vibration signal is larger or smaller than the amplitude output in the normal state, it can be determined that the operation of the fuel injection device is not normal. Therefore, the fuel injection device abnormality determination unit can determine the abnormality of the fuel injection device based on the vibration signal component extracted by the pressure signal processing unit.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a pressure sensor 30 for an internal combustion engine (hereinafter simply referred to as a pressure sensor) and a pressure signal processing device 50 according to an embodiment of the present invention. In this embodiment, the pressure sensor 30 and the pressure signal processing device 50 are shown. Is applied to a diagnosis of a fuel injection device 10 (hereinafter, referred to as an injector).

In the following description, a gasoline engine 11 using gasoline as an example of an internal combustion engine (hereinafter referred to as an engine) will be described. However, the present invention relates to a diesel engine using light oil as fuel. Is also applicable. The present invention is characterized in that the pressure sensor 30 is provided integrally with the injector 10.
First, the configuration of the injector 10 in which the pressure sensor 30 is integrally provided will be described with reference to FIGS.

The injector 10 according to this embodiment is similar to the injector 10 shown in FIG.
As shown in FIG. 1, the engine 11 is arranged directly on the cylinder head 12 of the engine 11. That is, the injector 1
Reference numeral 0 denotes a configuration in which the engine is mounted on the cylinder head 12 so as to face a combustion chamber 13 which is a combustion space of the engine 11. As shown in FIG. 1, the injector 10 roughly includes a housing 15, a holder 16, and a valve body 1.
7, a coil assembly 20, a needle valve 22, an injection port 23, a spring 24, and the like.

The housing 15 is constituted by first to third housings 15A to 15C. The first housing 15A is located at the center in the vertical direction in the figure (arrow A in the figure).
(A1, A2 direction) is formed. A fuel pumped from a fuel pump is supplied to an upper end of the fuel passage 18, and a pipe 21 made of a magnetic material is disposed inside the fuel passage 18 so as to be movable in the directions of arrows A1 and A2 in the figure.

A wiring connector 19 is provided on the outer periphery of the upper portion of the first housing 15A. To the wiring connector 19, a cable (not shown) connected to an engine control unit 40 (hereinafter, referred to as ECU) described later is connected. In addition, the wiring connector 19
Are connected to a coil assembly 20 arranged on the outer periphery of the vaporizing portion of the first housing 15A. Therefore, EC
When the injector drive signal is output from U40, the injector drive signal is supplied to the coil assembly 20 via the wiring connector 19, and the coil assembly 20 is configured to be excited.

As described above, the pipe 21 provided in the fuel passage 18 is made of a magnetic material. In addition, the pipe 21 has arrows A1,
It is configured to be movable in the A2 direction. Therefore, when the coil assembly 20 is excited, the pipe 21
Moves in the directions of arrows A1 and A2 in the figure. On the other hand, the second housing 15B is fixed to the first housing 15A so as to cover around the coil assembly 20. A valve body 17 is fixed to a lower end of the second housing 15B via a holder 16. In this fixed state, the flange part 28 formed on the upper part of the valve body 17 is in a state of being joined to the first housing part 15A via the spacer 25.

A needle valve 22 is provided inside the valve body 17. The needle valve 22 is configured to be integrally joined to the lower end of the pipe 21 described above. Therefore, as described above, the ECU 40
When the injector 21 outputs an injector drive signal and the pipe 21 moves in the directions of arrows A1 and A2 in the figure, the needle valve 22 also moves in the directions of arrows A1 and A2 in the figure. Further, a coil spring 2 is provided above the needle valve 22.
The coil spring 24 urges the needle valve 22 downward (in the direction of arrow A2).

The lower end of the needle valve 22 opens and closes an injection port 23 formed at the lower end of the valve body 17. That is, when the needle valve 22 moves in the direction of arrow A2 in the figure, the tip of the needle valve 22 closes the injection port 23, and the needle valve 22 moves in the direction of arrow A2 in the figure.
When moved in one direction, the tip of the needle valve 22 opens the injection port 23.

When the drive signal is not supplied from the ECU 40, since the coil assembly 20 is not excited, the pipe 21 and the needle valve 22 are displaced in the direction of arrow A2 by the elastic force of the coil spring 24. Is in a closed state. Meanwhile, EC
When the drive signal is supplied from U40, the coil assembly 20 is excited, and the magnetic force causes the pipe 21 and the needle valve 22 to be displaced in the direction of the arrow A1 against the elastic force of the coil spring 24, so that the injection port 23 is opened. It will be in the valved state. When the injection port 23 is opened, the fuel supplied from the fuel pump passes through the fuel passage 18 and the injection port 2
3 is injected into the combustion chamber 13.

The third housing 15C is provided with the second housing 15C.
Is fixed to the outer peripheral position of the housing 15B. A fixing screw portion 26 is formed on an outer peripheral portion of the third housing 15C. Further, a piezoelectric sensor 30 which is a main part of the present invention is provided on the outer peripheral portion of the third housing 15C. The piezoelectric sensor 30 is, for example, a piezoelectric element having an annular structure, and is disposed so as to surround an outer peripheral portion of the third housing 15C. The piezoelectric sensor 30 is fixed to a sensor fixed holder 31, and the sensor fixed holder 31 is fixed to the outer peripheral portion of the third housing 15C. Therefore, the piezoelectric sensor 30 is configured to be integrally fixed to the third housing 15C (that is, the injector 10) via the sensor fixing holder 31.

Further, a sensor spacer 32 is provided below the piezoelectric sensor 30. The sensor spacer 32 is interposed between the cylinder head 12 and the piezoelectric sensor 30 in a state where the injector 10 is disposed on the cylinder head 12. The sensor spacer 32 is, for example, an annular metal washer,
The function of preventing the piezoelectric sensor 30 from directly contacting the cylinder head 12 is provided.

The injector 10 having the above structure is attached to an opening 14 formed in the cylinder head 12. The shape of the opening 14 is a shape corresponding to the outer shape of the injector 10. Further, a screw portion 14A is formed at a predetermined portion of the upper portion of the inner wall of the opening portion 14,
A fixing screw 26 formed on the third housing 15C of the injector 10 is screwed into the screw 14A.

Accordingly, the injector 10 is fixed to the cylinder head 12 by screwing the fixing screw 26 to the screw 14A. In a state where the injector 10 is fixed to the cylinder head 12, the injector 1
The lower end of 0 (the end in the direction of arrow A <b> 2 in the figure) is in a state facing the combustion chamber 13 through the opening 14. In this fixed state, the pressure sensor 30 is pressed against the cylinder head 12 via the sensor spacer 32.

Accordingly, the combustion pressure in the combustion chamber 13 is applied to the injector 10, and the combustion pressure is applied to the pressure sensor 30 via the needle valve 22 and the housing 15. Therefore, according to the configuration of the present embodiment, the injector 1
0 by the pressure sensor 30 attached to the combustion chamber 13.
It becomes possible to detect the combustion pressure in the inside. On the other hand, as described above, the injector 10 is configured such that the needle valve 22 moves to inject fuel when a drive signal is supplied from the ECU 40. At the time of this fuel injection, high-pressure fuel is injected from the injection port 23, and therefore, the injector 10 generates vibration (hereinafter, referred to as injection vibration) due to the fuel injection.

This injection vibration does not occur when fuel is not being injected. Further, when the injection vibration, injection pressure of fuel injected from the injection port 23 (hereinafter, referred to as fuel injection pressure P _I) is known to correlate to. Therefore, by integrally attaching the pressure sensor 30 to the injector 10, it is possible to detect the operating state of the injector 10 (that is, whether fuel injection is performed or not) by the pressure sensor 30. can, and when doing the fuel injection, by utilizing the correlation between the injection time of the vibration and the fuel injection pressure, it is possible to detect the fuel injection pressure P _I. Further, as described above, the pressure sensor 30 can also detect the combustion pressure in the combustion chamber 13.

That is, according to the present embodiment, the operating state of the injector 10, the fuel injection pressure P _I , and the combustion pressure in the combustion chamber 13 can be detected by one pressure sensor 30. Thus, by one pressure sensor 30,
Since the above-mentioned state detection can be performed, the configuration around the cylinder head 12 can be simplified as compared with a configuration in which sensors for detecting the individual states are separately provided.

Subsequently, the pressure sensor 30 having the above-described structure is used.
Is mainly connected to the pressure signal processing device 50 to which FIG.
This will be described with reference to FIG. The pressure signal processing device 50
In brief, it is constituted by the ECU 40 and the alarm 41. The ECU 40 constitutes pressure signal processing means for processing a signal including the above-described state detection information output from the pressure sensor 30 (hereinafter, this signal is referred to as a pressure signal).

As shown in FIG. 3, the ECU 40 includes a low-pass filter 42 (hereinafter referred to as LPF), a high-pass filter 43 (hereinafter referred to as HPF), a central processing unit 44 (hereinafter referred to as CPU), and a read-only memory 45. (Hereinafter referred to as a ROM). The alarm 41 is for issuing a warning when an abnormality is determined in an abnormality determination process of the injector 10 performed by the ECU 40 described later. The warning means is not specified. For example, an alarm lamp may be provided on an instrument panel in the driver's seat to light it, or a warning sound may be generated.

Although not shown, the ECU 40 is connected to various sensors for detecting the operating state of the engine 11, such as a rotational speed sensor and an accelerator opening sensor. The ECU 40 detects the operating state of the engine 11 based on the output signals of these sensors, performs optimal fuel injection control according to the detected operating state, and performs optimal fuel injection to the injector 10. It outputs a drive signal that can be performed.

Here, the pressure signal output from the pressure sensor 30 will be described. As described above, the pressure sensor 3
The pressure signal output from 0 includes three pieces of information such as the operating state of the injector 10, the fuel injection pressure P _I , and the combustion pressure in the combustion chamber 13. Among them, the information can be obtained as a vibration signal of the injector 10 generated at the time of injection (hereinafter, this signal is referred to as an injector operation signal), and the other information is obtained as a combustion pressure signal generated in the explosion stroke. Obtainable.

The above-mentioned injector operation signal is about 7 kHz.
It is known that the signal has a relatively high frequency component of z to 12 kHz. It is known that the combustion pressure signal is a signal having a frequency component lower than the frequency band of the injector operation signal of about 5 kHz or less. As described above, since the injector operation signal and the combustion pressure signal have different frequency characteristics, it is possible to separate the pressure signal output from the pressure sensor 30 into the injector operation signal and the combustion pressure signal. In this embodiment, the pressure sensor 30
The LPF 42 and the HPF 43 described above are used as means for separating the pressure signal output from the ECU into an injector operation signal and a combustion pressure signal.

Specifically, since the injector operation signal is a signal having a relatively high frequency component as described above,
By passing through F43, the injector activation signal can be separated from the pressure signal. Further, since the combustion pressure signal is a signal having a low frequency component, the combustion pressure signal can be separated from the pressure signal by passing through the LPF 42. The injector operation signal and the combustion pressure signal generated in this way are sent to the CPU 44, and the CPU 44 performs predetermined processing described later based on the signals.

FIG. 5 shows a pressure signal and the LPF 42 (cutoff frequency 1.5 kHz) and the HPF 43 from the pressure signal.
4 shows the injector activation signal and the combustion pressure signal separated by using (cutoff frequency 2.0 kHz). In each figure, the vertical axis indicates the output voltage,
The horizontal axis indicates time. Each drawing also shows the injection signal.

FIG. 5A shows a pressure signal output from the pressure sensor 30. FIG. 5B shows the LP.
Shown is the combustion pressure signal separated from the pressure signal by passing through F42. FIG. 2 also shows a waveform of a combustion pressure signal detected by a separate combustion pressure detection device (referred to as a reference combustion pressure signal waveform). When this reference combustion pressure signal waveform is compared with the combustion pressure signal waveform obtained in the present embodiment, the combustion pressure signal waveform is very similar to the reference combustion pressure signal waveform, and thus the pressure sensor 30 is connected to the injector 10. It can be seen that the combustion pressure can be detected with high accuracy even with the attached structure.

FIG. 5C shows the injector operation signal separated from the pressure signal by passing through the HPF 43. As described above, when the injection occurring in the injector 10 during fuel injection vibration has a correlation with the fuel injection pressure, thus also the injector actuation signal and the fuel injection pressure P _I have the correlation. That is, it is possible to determine the fuel injection pressure P _I from the injector actuation signal.

Here, the fuel injection from the injector operation signal is performed.
Shot pressure P_IThe following describes a specific method for determining Burning
Injection pressure P_ICan be injected by using FIG.
The amplitude of the operation signal (arrow V in FIG. 5C)_PFrom)
You can ask. Fig. 6 shows the experimentally determined indicators.
Maximum amplitude V of the actuator operation signal_PAnd fuel injection pressure P_IRelationship with
FIG. As shown in the figure, the injector
Maximum amplitude V of motion signal_PAnd fuel injection pressure P_IIs approximately proportional
is there. Therefore, the maximum amplitude V shown in FIG. _PAnd fuel injection pressure P
_IIs stored in the ROM 45 as a map.
The maximum required from the injector operation signal
Amplitude V_PFrom the fuel injection pressure P_ICan be calculated
You.

Next, a description will be given of an abnormality detection process of the injector 10 which is performed based on the maximum amplitude _VP and the fuel injection pressure P _I obtained as described above. FIG.
5 is a flowchart showing an abnormality detection process executed by the CPU 44 in the ECU 40. When the abnormality detection process shown in the figure is started, first, in step 100, it is determined whether or not the injector 10 is injecting fuel.
The determination process in step 100 is performed based on, for example, whether a drive signal is supplied to the injector 10 from the ECU 40.

As a result, when it is determined that the drive signal is not supplied from the ECU 40, the abnormality determination processing for the injector 10 cannot be performed, and therefore the processing is performed in step 1
02, the presence or absence of an unprocessed injector is determined.
Here, the unprocessed injector refers to an injector for which an abnormality determination process has not been performed. The engine 11 has a plurality of cylinders, and an injector 10 is provided for each cylinder. Since the abnormality determination processing according to the present embodiment is performed for each of the injectors 10, Step 10
Two processes are provided. If it is determined in step 102 that there is an unprocessed injector, the process returns to step 100, and the undetermined injector is subjected to abnormality determination processing in step 100 and subsequent steps. On the other hand, the abnormality determination processing is performed for all the injectors 10, and thus, if it is determined in step 102 that there is no unprocessed injector, the abnormality determination processing ends.

On the other hand, in step 100, when the driving signal from the ECU40 to the injector 10 is determined to have been supplied, the process proceeds to step 10, the detection process of the maximum amplitude V _P of the above-mentioned is performed. That is, as described above, to separate the injector actuation signal through the pressure signal output from the pressure sensor 30 to the HPF 43, determine the maximum amplitude V _P from the injector actuation signal. In addition, in subsequent step 106, based on the maximum amplitude V _P obtained in Step 104, by using a map corresponding to FIG. 6 which is stored in advance in the ROM 45, the fuel injection pressure P _I
Is calculated.

[0044] Subsequently in step is performed 108, the maximum amplitude V _P obtained in Step 104, whether or not within the range of the amplitude which occurs when the injector 10 is operating normally or not. If the injector 10 as described above performs the fuel injection, the vibration is generated in the injector 10, the magnitude of the vibration is proportional to the maximum amplitude V _P. Also, depending on the operating state, the injector 10
Of the fuel injection amount changes, and accordingly, the magnitude of the vibration generated in the injector 10 also changes. At this time, a change in vibration generated when the injector 10 is operating normally can be obtained in advance by an experiment.

Now, the maximum amplitude V _P corresponding to the maximum vibration generated when the injector 10 is operating normally obtained by the experiment is set as the maximum amplitude value V _MAX, and when the injector 10 is operating normally. the maximum amplitude V _P corresponding to the minimum of the vibration generated to the minimum amplitude value V _MIN. In step 108, the maximum amplitude V _P of the current injector 10 calculated in step 104, whether a value between the maximum amplitude value V _MAX and the minimum amplitude value V _MIN described above can be determined (V _{MIN <V P <V MAX)} .

[0046] Then, if it is a negative determination in step 108, i.e. if the maximum amplitude V _P is the maximum amplitude value V _MAX is larger than or the maximum amplitude V _P is determined to the minimum amplitude value V _MIN smaller than the processing Proceeds to step 110 and activates an alarm indicating that injector 10 is not operating properly. This allows the driver to recognize that the injector 10 is not operating properly.

Here, the maximum amplitude V of the injector 10
_{If P} is equal to or greater than the maximum amplitude value V _MAX, a case such as excessive drive signal from the ECU40 to example injector 10 for some reason it has been supplied, and the maximum amplitude V _P is the minimum amplitude value V _MIN of the injector 10 In the following cases, for example, E
This is the case where no drive signal is supplied from the CU 40.

On the other hand, if a positive determination is made in step 108, that is, if it is determined that the injector 10 is operating normally, the process proceeds to step 112. In step 112, it is determined whether or not the fuel injection pressure P _I obtained in step 106 is within a predetermined pressure range. The processing in step 108, even when it is determined that the injector 10 is operating correctly, for example, abnormality of the fuel pump, the abnormality of the suction tube for transporting the fuel, the fuel injection pressure P _I is the default The fuel pressure may not be reached. Step 112 is provided to detect these abnormalities.

Specifically, in the CPU 44, the ECU
The maximum fuel injection pressure P _MAX and the minimum fuel injection pressure P _MIN generated when the injector 10 normally performs the injection processing based on the drive signal output from 40 are calculated, and the current fuel injection pressure P _MIN obtained in step 106 is calculated. It is determined whether the fuel injection pressure P _I is a value between the above-described maximum fuel injection pressure P _MAX and the minimum fuel injection pressure P _MIN (P _MIN <P _I <P
_MAX ).

If a negative determination is made in step 112, that is, it is determined that the current fuel injection pressure P _I is larger than the maximum fuel injection pressure P _MAX or that the fuel injection pressure P _I is smaller than the minimum fuel injection pressure P _MIN. in a case where it is, the process proceeds to step 114, abnormality in the fuel injection pressure P _I starts an alarm to indicate that has occurred. This allows the driver to recognize that an abnormality has occurred in the fuel injection pressure P _I (that is, there is a possibility that an abnormality has occurred in the fuel pump or the suction tube).

In the above-described embodiment, the processing of steps 108 to 114 shown in FIG. 4 corresponds to "fuel injection apparatus abnormality determination means" described in the claims. In the above embodiment, the engine was not particularly limited.
The present invention is applicable to various engines. That is,
It can be widely applied to four-cylinder diesel engines, six-cylinder diesel engines, four-cylinder gasoline engines, six-cylinder gasoline engines, and the like.

In the above embodiment, the pressure sensor 3
The arrangement position of 0 is defined as the outer peripheral position of the housing of the injector 10. However, the disposition position of the pressure sensor 30 is not limited to this, and may be disposed at any other position as long as it can detect the combustion pressure and the vibration generated in the injector 10. FIG. 7 shows an example in which the pressure sensor 30 is arranged at another position. In the configuration shown in FIG. 7A, the pressure sensor 30 is arranged at a joint position between the upper surface of the flange portion 28 of the valve body 17 and the housing 15. In the configuration shown in FIG. 7B, the pressure sensor 30 is connected to the lower surface of the flange 28 of the valve body 17 and the housing 15.
It is arranged between the lower end and the flange portion 29. In the configuration shown in FIG. 7C, the pressure sensor 30 is disposed between the second housing 15B and the third housing 15C that constitute the housing 15. As described above, the arrangement position of the pressure sensor 30 can be variously selected.

In this embodiment, the pressure signal is separated into the injector operation signal and the combustion pressure signal by performing the filtering process on the injector operation signal as described above. A configuration may be employed in which each signal is separated using signal separation means. In the above embodiment, only the injector operation signal and the combustion pressure signal are separated from the pressure signal. However, the pressure signal detected by the pressure sensor 30 includes vibration generated by knocking. Therefore, in addition to the LPF 42 and HPF 43 described above,
By further providing a filter having an appropriate band capable of extracting knocking vibration, it is possible to adopt a configuration in which a knock signal is detected.

[0054] Further, in the above embodiment, a configuration using the fuel injection pressure P _I obtained from the injector actuation signal to the abnormality determination of the injector 10, the fuel injection pressure P _I
The use of the fuel injection method is not limited to this. For example, it is possible to calculate the amount of fuel actually injected by the injector 10 based on the fuel injection pressure P _I and reflect the calculated amount in the air-fuel ratio control. It is.

Further, in the above-described embodiment, the configuration in which the pressure sensor is provided on the injector is shown. However, from the viewpoint of making the area around the cylinder head compact, the pressure sensor is provided on the valve provided on the cylinder head. A configuration is also conceivable. In the case of this configuration, the detection of the combustion pressure is performed with the valve closed.

[0056]

According to the present invention, the following various effects can be realized. According to the first aspect of the present invention, it is possible to detect the vibration generated when the fuel injection device injects the fuel with the pressure sensor for the internal combustion engine, so that the pressure vibration output from the pressure sensor for the internal combustion engine is detected. It can be determined whether the fuel injection device is operating properly based on the following.

According to the second aspect of the present invention, the vibration generated when the fuel injection device injects the fuel and the combustion pressure in the combustion space (combustion chamber) are determined by one internal combustion engine pressure sensor. Both can be detected, and the configuration around the cylinder head can be simplified. According to the third aspect of the present invention, since the vibration signal component accompanying the injection of the fuel injection device is extracted from the pressure signal output from the pressure sensor for the internal combustion engine by the pressure signal processing means, the signal component related to this injection Can be used separately.

According to the fourth aspect of the present invention, since the vibration signal component of the fuel injection device extracted by the pressure signal processing means is a signal reflecting the state of the fuel injection device, the fuel injection device abnormality determination means It is possible to determine the abnormality of the fuel injection device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an injector provided with a pressure sensor and a pressure signal processing device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an attachment position of an injector in an internal combustion engine.

FIG. 3 is a block diagram of a pressure signal processing device according to one embodiment of the present invention.

FIG. 4 is a flowchart illustrating a process performed by the pressure signal processing device.

FIG. 5 is a diagram showing a pressure signal output from the pressure signal, and a combustion pressure signal and an injector operation signal generated by the pressure signal processing device.

FIG. 6 is a diagram showing a relationship between an amplitude of an injector operation signal and a fuel injection pressure.

FIG. 7 is a view showing a modification of the mounting position of the pressure sensor with respect to the injector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Injector 11 Internal combustion engine 12 Cylinder head 13 Combustion chamber 15 (15A-15C) Housing 17 Valve body 20 Coil assembly 22 Needle valve 23 Injection port 24 Coil spring 26 Fixing screw part 30 Pressure sensor 31 Sensor fixing holder 32, 33 Sensor spacer 40 ECU (Engine Control Unit) 41 Alarm 42 LPF (Low Pass Filter) 43 HPF (High Pass Filter) 44 CPU (Central Processing Unit) 50 Pressure Signal Processing Unit

Continued on the front page F-term (reference) 2F055 AA21 AA23 BB19 CC55 DD09 EE23 FF28 FF31 GG11 HH03 3G066 AA02 AA07 AB02 AD12 BA67 BA69 CC01 CC06T CC14 CD25 CD26 CD28 DC00 DC04 DC09 DC17 3G084 AA01 AA03 FA33 FA33

Claims (4)

[Claims] 1. A pressure sensor for an internal combustion engine, which is provided integrally with a fuel injection device attached to a main body of the internal combustion engine. 2. A fuel injection device, which is mounted on a main body of an internal combustion engine so as to face a combustion space, and is integrally provided with a fuel injection device. A pressure sensor for an internal combustion engine, which detects accompanying vibration and outputs a pressure signal. 3. A pressure signal processing device comprising: a pressure signal processing means for processing a pressure signal output by the pressure sensor for an internal combustion engine according to claim 2; A pressure signal processing device configured to extract a vibration signal component accompanying the injection of the fuel injection device from a pressure signal output by a pressure sensor. 4. The pressure signal processing device according to claim 3, further comprising: a fuel injection device abnormality determination unit that determines abnormality of the fuel injection device based on the vibration signal component extracted by the pressure signal processing unit. A pressure signal processing device comprising: