JP2001207905A - Abnormality detection device of intake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely judge abnormality of an intake system by enabling to precisely maintain a reference pressure Pa even when a environment varies, without using an atmospheric pressure sensor. SOLUTION: Abnormality of the intake system is precisely determined by enabling to precisely maintain a reference pressure Pa even when environment varies, without using an atmospheric pressure sensor by prohibiting determination of abnormality as there is the possibility of the change in environment (difference of elevation) when specified time (t) passes after the reference pressure Pa is memorized while determining abnormality of the intake system when a detection pressure P of a boost pressure sensor 27 is less than (Pa+P1) by comparing a value that a specified value P1 is added to the reference pressure Pa and the detection pressure P of the boost pressure sensor 27 during working of an engine 1 with each other after the reference pressure Pa is memorized by memorizing a detection value of the boost pressure sensor 27 in an idling state of the engine 1 as the reference pressure Pa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detection device for an intake system, that is, an intake system for judging abnormalities of a pressure sensor and an intake passage in an internal combustion engine in which a pressure sensor detects pressure of the intake system.

[0002]

2. Description of the Related Art The intake pressure of an internal combustion engine (engine) is detected by a pressure sensor provided in an intake passage, and the fuel amount and the like are controlled in accordance with the detected intake pressure value. Therefore, the detection value of the pressure sensor for detecting the intake pressure is required to be accurate. However, abnormality in the detection value of the pressure sensor due to failure of the pressure sensor itself, clogging of the intake path due to clogging of the air cleaner, or clogging of foreign matter (soot or the like) due to introduction of exhaust gas into the intake path. (Abnormal intake system). Therefore, conventionally, an abnormality detection device that determines a failure of a pressure sensor or an abnormality of an intake path has been proposed (for example, Japanese Unexamined Patent Application Publication No.
9-112316).

The conventional abnormality detecting device detects an intake pressure by an intake pressure sensor, and learns a detected value of the intake pressure sensor in a stable state, that is, a predetermined reference value and a current detected value of the intake pressure sensor. And when the difference is large, an abnormality of the intake system including an abnormality of the intake pressure sensor is determined. For this reason, a reference intake pressure value is derived without using an atmospheric pressure sensor, and based on the reference value, the pressure sensor itself malfunctions and does not function normally, or an abnormality such as clogging occurs in the intake path. Can be determined.

[0004]

However, the conventional abnormality detecting device has a problem that when there is a large change in the environment between the place where the predetermined reference value is learned and the place where the intake pressure is detected by the intake pressure sensor. For example, if a significant difference in altitude occurs between a place where the intake pressure is detected by the intake pressure sensor by climbing a steep slope after deriving a predetermined reference value and a place where the predetermined reference value is derived, the current detection value is Since the pressure change due to the altitude difference is reflected, the difference between the detected value and the reference value becomes large even when the pressure sensor and the intake path are normal, and the abnormality of the intake system is determined. In addition, even when the intake air temperature changes, the detection value of the intake air pressure sensor may be affected by the temperature change and accurate determination may not be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an intake system abnormality detecting device capable of accurately determining an intake system abnormality even when an environmental change occurs without using an atmospheric pressure sensor. The purpose is to do.

[0006]

According to the first aspect of the present invention, a pressure storage means stores a pressure value of a pressure sensor in a predetermined operating state of an internal combustion engine as a reference pressure value. After the value is stored, the determination control means compares the reference pressure value with the detected pressure value of the pressure sensor during operation of the internal combustion engine to determine whether the intake system is abnormal. After a lapse of time, there is a possibility that an environment change may occur between the time when the reference pressure value is stored and the time when the pressure sensor detects, so that the abnormality determination of the intake system is prohibited, and the environment change is performed without using the atmospheric pressure sensor. Even if it occurs, the abnormality of the intake system is accurately determined.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the stop abnormality determining means determines a preset stop reference pressure value and a detected pressure value of the pressure sensor during stoppage of the internal combustion engine. In this case, the abnormality of the intake system at the time of stop is determined.

More specifically, the internal combustion engine is a diesel engine whose intake pressure is substantially equal to the atmospheric pressure, and a reference value which is a pressure value of the pressure sensor in a predetermined operating state is a pressure value of the pressure sensor in an idling state. It is preferred that Then, the pressure value of the pressure sensor when the accelerator opening is equal to or more than the predetermined opening at the predetermined rotation speed of the diesel engine is set as the detected pressure value of the pressure sensor during operation of the internal combustion engine, and the pressure sensor detects the pressure value with respect to the reference value. It is preferable to determine the abnormality of the intake system when the pressure value is not high. Prior to this determination, the stop abnormality determination means compares the pressure value of the pressure sensor when the diesel engine is not rotating with the lowest conceivable pressure value (stop reference pressure value). It is preferable to determine the abnormality of the pressure sensor itself when the pressure value becomes equal to or less than the pressure value.

[0009]

FIG. 1 is a schematic configuration of an internal combustion engine (diesel engine) provided with an intake system abnormality detection device according to an embodiment of the present invention. FIG. 2 is a determination control means and stop abnormality determination. The control flowchart of the means is shown.

As shown in FIG. 1, a combustion chamber 2 is formed in each cylinder of a diesel engine (engine) 1, and an intake port 3 opened and closed by an intake valve 11 is provided for each combustion chamber 2. An intake passage 4 is connected to the intake port 3, and outside air is sucked into the intake passage 4 via an air cleaner 5, a supercharger 6 and an intercooler 7 (white arrows in the figure),
Outside air is introduced from the intake passage 4 into the combustion chamber 2. Also, an exhaust port 9 opened and closed via an exhaust valve 12 for each combustion chamber 2
The exhaust port 9 is connected to the exhaust passage 8. The exhaust passage 8 is connected to the supercharger 6, and the exhaust gas is discharged to the outside via the catalyst 10 after the supercharger 6 rotates to supercharge the intake air (black arrows in the figure).

The intake passage 4 and the exhaust passage 9 are connected to the EGR passage 2
The EGR passage 21 is opened and closed by an EGR valve 22, and an appropriate amount of exhaust gas is mixed into the intake passage 4. By mixing the exhaust gases to the intake passage 4, and appropriately controls the air excess ratio is suppressed nitrogen oxides (NO _X) and suspended particulate matter (PM) to a minimum. Since the diesel engine does not have an intake throttle, the intake air amount cannot be controlled to control the excess air ratio, and the excess air ratio is controlled by mixing the exhaust gas into the intake passage 4 so that the nitrogen oxidation is performed. things the (NO _X) and suspended particulate matter (PM) are minimized.

The intake passage 4 downstream of the EGR valve 22
Is provided with an intake air temperature sensor 25 for detecting an intake air temperature and a boost pressure sensor 27 as a pressure sensor for detecting an intake air pressure via a boost pressure hose 26. Also, the crank angle of the engine 1 is detected to determine the engine speed.
A crank angle sensor 28 for detecting Ne is provided. Information detected by the intake air temperature sensor 25, the boost pressure sensor 27, and the crank angle sensor 28 is input to the ECU 29. Also, E
Accelerator opening (APS) information is input to the CU 29, and the ECU 29 sends the fuel injection pump 30
A control signal is sent to the electronic governor 31 and the timer control valve 32 to control the fuel injection amount.

The ECU 29 is provided with a pressure storage means for storing the detected pressure value P of the boost pressure sensor 27 at the time of idling as a predetermined operating state of the engine 1 as a reference pressure value Pa substantially corresponding to the atmospheric pressure. Also, the ECU 29
During the operation of the engine 1 after the reference pressure value Pa is stored. For example, when the engine speed Ne is N rpm (1600 rpm)
APS is X% (70%) or more: In the case of a flat ground, the detected pressure value P of the boost pressure sensor 27 and the reference pressure value Pa are compared with each other in the operating state す る which rises by about 250 mmHg with respect to the atmospheric pressure. 27 detected pressure value P is 250mmH
g is smaller than the reference value Pa (for example, 100 mmHg).
And a determination control means for determining an abnormality of the intake system when the value does not exceed the value added to.

Further, when the reference time Pa reaches the predetermined time t after the reference pressure value Pa is stored, the determination control means determines that the predetermined time t is, for example, 300 seconds (a height difference that generates a pressure difference of 100 mmHg is about 1000 m). , The shortest travel time, which is considered to be the fastest at an altitude of about 1000 m, is about 300 sec.), When the reference pressure value Pa is stored and when the boost pressure sensor 27 detects, the environmental change, that is, , A pressure change affecting the judgment occurs, an altitude difference occurs and the reference pressure value Pa
Since there is a possibility that the intake pressure value becomes excessively lower than the + predetermined value P1, it has a function of prohibiting abnormality determination of the intake system. Although the predetermined time t is selected based on the case where the height difference is a factor, other environmental changes (such as a temperature difference) are determined by the predetermined time t.
It can also be applied as a selection factor.

Therefore, even if an environmental change occurs without using an atmospheric pressure sensor, a value for determining an abnormality in the intake system can be held with high accuracy, and the abnormality can be accurately determined. .

The ECU 29 stores a preset stop reference pressure value, for example, a minimum pressure value P2 (for example, 300 mmHg: equivalent to an altitude of 6000 m) that can be considered when the vehicle runs.
And the detected pressure value P of the boost pressure sensor 27 when the engine 1 is not rotating, that is, the detected pressure value P of the boost pressure sensor 27 when the engine 1 is stopped,
If the detected pressure value P of the boost pressure sensor 27 is less than the minimum pressure value P2, it is determined that there is no output from the boost pressure sensor 27, and the intake system (the boost pressure sensor 27
Stop abnormality determination means for performing abnormality determination of itself) is provided.

The determination control means and the stop abnormality determination means will be described in detail with reference to FIG.

As shown in the figure, in step S1, it is determined whether the IG switch is on and the engine speed Ne is 0 rpm, that is, whether the engine 1 is not rotating.
When it is determined in step S1 that the engine 1 is not rotating, in step S2, the lowest pressure value P2 that can be considered when the vehicle runs (for example, 300 mmHg: equivalent to an altitude of 6000 m)
And the current detected pressure value P of the boost pressure sensor 27 is compared. In step S2, the detected pressure value P is equal to the minimum pressure value P2.
Is less than the pressure, it is determined that there is no output from the boost pressure sensor 27.
Is determined to be abnormal (stop abnormality determining means), and a warning light A indicating that the boost pressure sensor 27 itself is abnormal such as disconnection of the electric wiring is turned on in step S3.

When it is determined in step S1 that the engine 1 is rotating, and in step S2, the detected pressure value P
Is not less than the minimum pressure value P2, that is, the detected pressure value P
Is greater than or equal to the minimum pressure value P2, it is determined in step S4 whether or not the engine 1 is idling, which is a predetermined operating state. When it is determined in step S4 that the engine 1 is idling, the detected pressure value P of the boost pressure sensor 27 is stored as a reference pressure value Pa (corresponding to substantially atmospheric pressure) in step S5 (pressure storage means). That is, in the case of a diesel engine, since the intake throttle is not provided, or the intake throttle is not used at the time of idling, the detected pressure value P of the boost pressure sensor 27 during idling becomes substantially equal to the atmospheric pressure, and the boost pressure sensor 27
Can be regarded as the atmospheric pressure.

In step S5, the detected pressure value P is set to the reference pressure value.
After storing as Pa, it is determined in step S6 whether the reference pressure value Pa is equal to or greater than the determination value P3. The determination value P3 is, for example,
The pressure is set to 600 mmHg (environmental conditions that correspond to an altitude of 2000 m and the detected pressure value P of the boost pressure sensor 27 may not be sufficiently increased). When it is determined in step S6 that the reference pressure value Pa substantially equivalent to the atmospheric pressure is equal to or greater than the determination value P3,
Since the detection pressure value P of the boost pressure sensor 27 is sufficiently increased, the timer is started in step S7, and the process proceeds to step S4. If it is determined in step S6 that the reference pressure value Pa is less than the determination value P3, the process returns because the detection pressure value P of the boost pressure sensor 27 may not be sufficiently increased.

If it is determined in step S4 that the engine 1 is not idling, it is determined in step S8 whether the reference pressure value Pa has been stored. Normally, after the engine 1 is started, the vehicle travels through the idling state, so that the above-described processes in steps S4 to S7 are executed, and the reference pressure value Pa is already stored. In step S8, the reference pressure value Pa is stored. It is determined that pressure value Pa has been stored. If it is determined in step S8 that the reference pressure value Pa is not stored, a return is made, so that the process can proceed to the next step after the reference pressure value Pa is stored.

After it is determined in step S8 that the reference pressure value Pa has been stored, the timer is started (step S7).
It is determined in step S9 whether a predetermined time has elapsed since the start. That is, in step S9, it is determined whether the elapsed time T is less than or equal to the predetermined time t. Elapsed time T in step S9
Is determined to exceed the predetermined time t, the stored reference pressure value Pa is deleted in step S10, and the process returns (function for inhibiting abnormality determination).

For example, assuming that the vehicle has climbed at an altitude of about 1000 m at the highest speed after storing the reference pressure value Pa,
A pressure difference of 0 mmHg will occur. Since the boost pressure sensor 27 detects an absolute pressure, if a pressure difference of 100 mmHg is generated, the detection value of the boost pressure sensor 27 may be excessively low with respect to the reference pressure value Pa. Therefore, about 1000
A predetermined time t (for example, 300 sec) is set as the shortest running time considered to be able to climb the altitude of m at the fastest speed. If the elapsed time T exceeds the predetermined time t, an environmental change (altitude difference) affecting the determination is made. ) May occur, the process of the abnormality determination is prohibited as a return, and the reference pressure value Pa can be stored again.

Therefore, even if an environmental change (altitude difference) occurs without using an atmospheric pressure sensor, the reference pressure value Pa for judging the abnormality of the intake system can be held with high accuracy.

If it is determined in step S9 that the elapsed time T is shorter than the predetermined time t, that is, if it is determined that the environment such as the altitude has not changed significantly since the reference pressure value Pa was stored, In step S11, the engine speed Ne is N
rpm (eg, 1600 rpm) and APS is X% (eg,
70%), that is, whether the engine 1 is under a certain load condition or not. If the engine 1 is under a certain load condition, on a flat ground, the intake pressure increases relative to the atmospheric pressure by P ₀ (for example, about 250 mmHg). If it is determined in step S11 that the engine 1 is at or above a certain load condition, the process proceeds to step S9 and waits for the engine 1 to be in or above a certain load condition within a predetermined time t.

If it is determined in step S11 that the engine 1 is under a certain load condition, the boost pressure sensor 27
A predetermined pressure P1 (for example, 10
In step S12, the value obtained by adding 0 mmHg) is compared. If more than the load conditions that the engine 1, the case of flat ground, the intake pressure to the atmospheric pressure because relatively P ₀ increases, detecting the addition of P ₀ is less than the predetermined value P1 to a reference pressure value Pa with a margin This is a comparison value with the pressure value P.

If it is determined in step S12 that the detected pressure value P is equal to or greater than the value obtained by adding the predetermined value P1 to the reference pressure value Pa (Pa + P1), the detection value of the boost pressure sensor 27 has been obtained normally. , Return. If it is determined in step S12 that the detected pressure value P is less than the value (Pa + P1), the intake pressure has not risen in the predetermined state with respect to the reference pressure value Pa, and thus the intake system may be clogged. Is present (it is determined in step S2 that the boost pressure sensor 27 itself is not abnormal), and a warning lamp B indicating that an abnormality has occurred in the intake path or the like is turned on in step S13.

Therefore, on the assumption that there is no environmental change (altitude difference) affecting the determination of an abnormality in the intake system,
Without using an atmospheric pressure sensor, it is possible to determine an abnormality of the boost pressure sensor 27 itself and an abnormality such as clogging of the intake system.

In the above embodiment, the boost pressure sensor 2
7 is provided with a warning light A for warning of an abnormality of itself and a warning light B for warning of an abnormality of the intake path. However, a single warning light may be used to simply warn of an abnormality of the intake system. In addition, although the present invention is applied to a diesel engine that is not affected by the intake throttle at idling, even if the engine is throttled at idling, the reference pressure value Pa
The above technique can be applied by correcting the comparison value or the comparison value.

In the embodiment described above, the detection value of the boost pressure sensor 27 in the idling state of the engine 1 is stored as the reference pressure value Pa corresponding to the atmospheric pressure, and the reference pressure value is stored.
After Pa is stored, the value obtained by adding the predetermined value P1 to the reference pressure value Pa is compared with the detected pressure value P of the boost pressure sensor 27 during operation of the engine 1, and the detected pressure value P of the boost pressure sensor 27 is determined. If it does not satisfy (Pa + P1), it is determined that the intake path is abnormal. Then, when a predetermined time t has elapsed after the reference pressure value Pa is stored, the environment (height difference) may be changed, so that the determination of the abnormality is prohibited. For this reason, it is possible to accurately maintain the reference pressure value Pa even if an environmental change occurs without using an atmospheric pressure sensor, and it is possible to accurately determine an abnormality in the intake system.

Since it is determined whether or not the detected pressure value P of the boost pressure sensor 27 is equal to or higher than the minimum pressure value P2 while the engine 1 is idling, the boost pressure sensor 27 (intake system) itself at the time of stoppage is determined. Can be determined, and an abnormality that cannot be determined by comparing the above-described reference value and the detected value can be determined.

[0032]

According to the first aspect of the present invention, the pressure storage means stores the pressure value of the pressure sensor in a predetermined operating state of the internal combustion engine as a reference pressure value, and after the reference pressure value is stored, the determination control is performed. The means compares the reference pressure value with the detected pressure value of the pressure sensor during operation of the internal combustion engine to determine whether the intake system is abnormal, and stores the reference pressure value when a predetermined time has elapsed after the reference pressure value is stored. Since the environmental change may occur between the time when the pressure is detected and the time when the pressure sensor detects, the abnormality determination of the intake system is prohibited. Therefore, even if the environmental change occurs without using the atmospheric pressure sensor, the intake system may be changed. Can be accurately determined.

[0033] In the present invention according to claim 2, in addition to the configuration of claim 1, the stop abnormality judging means determines a predetermined stop reference pressure value and a detected pressure value of the pressure sensor during stoppage of the internal combustion engine. Is compared to make an abnormality determination, so that an abnormality determination of the intake system at the time of stoppage can be made.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an internal combustion engine (diesel engine) provided with an intake system abnormality detection device according to an embodiment of the present invention.

FIG. 2 is a control flowchart of a determination control unit and a stop abnormality determination unit.

[Explanation of symbols]

 Reference Signs List 1 diesel engine (engine) 3 intake port 4 intake passage 5 air cleaner 6 turbocharger 26 boost pressure hose 27 boost pressure sensor 29 ECU

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Setsuo Nishihara 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F-term (reference) 3G084 AA01 BA33 CA03 CA07 DA13 DA27 EA07 EA11 EB20 EB22 EB24 EC01 FA02 FA11 FA33 FA38 3G301 JB09 JB10 KA07 KA28 NA08 ND25 ND30 ND40 NE20 PA07Z PA10Z PE01Z PE03Z

Claims (2)

[Claims] 1. An intake system abnormality detecting device, comprising: a pressure sensor for detecting an intake system pressure of an internal combustion engine; and determining an intake system abnormality based on a detected value of the pressure sensor. While having a pressure storage means for storing the pressure value of the pressure sensor in the state as a reference pressure value,
After the reference pressure value is stored, the reference pressure value is compared with the detected pressure value of the pressure sensor during operation of the internal combustion engine to determine whether the intake system is abnormal, and the reference pressure value is stored and determined. An intake system abnormality detection device comprising: a determination control unit that prohibits an intake system abnormality determination after a lapse of time. 2. A stop abnormality according to claim 1, wherein a predetermined stop reference pressure value is compared with a detected pressure value of said pressure sensor during stoppage of said internal combustion engine to determine an abnormality of said intake system at stoppage. An abnormality detection device for an intake system, comprising a determination unit.