JP6534876B2 - engine - Google Patents

Description

  The invention relates mainly to an engine provided with at least two pressure sensors.

  2. Description of the Related Art Conventionally, various pressure sensors for detecting pressure such as atmospheric pressure, intake pressure, and exhaust pressure are provided in an engine. Patent documents 1 to 3 disclose an engine that includes these pressure sensors and performs control according to the detected value of the pressure sensors.

  The engine of Patent Documents 1 and 2 includes an atmospheric pressure sensor, an intake pressure sensor, and a control unit such as an ECU. The control unit obtains a difference between detection values of the atmospheric pressure sensor and the intake pressure sensor at the timing when the atmospheric pressure and the intake pressure become equal (after the engine is stopped, etc.). The control unit determines that the atmospheric pressure sensor or the intake pressure sensor is abnormal if the difference between the detection values of the atmospheric pressure sensor and the intake pressure sensor exceeds a predetermined threshold.

  The engine of Patent Document 3 includes a pressure sensor and an ECU. The pressure sensor is disposed inside the intake pipe. In this engine, one pressure sensor is used to detect atmospheric pressure and intake pressure. That is, the ECU handles the detection value of the pressure sensor immediately after the start of the engine as the atmospheric pressure. Also, the ECU handles the detected value of the pressure sensor during operation of the engine as the intake pressure. The ECU corrects the intake pressure using the atmospheric pressure detected in advance to obtain a corrected intake pipe pressure, and determines the fuel injection amount and the ignition timing based on the corrected intake pipe pressure.

JP 2008-303718 A JP, 2009-174501, A Unexamined-Japanese-Patent No. 5-149187

  By the way, patent documents 1 and 2 aim at detecting and notifying a user of abnormalities in an atmospheric pressure sensor or an intake pressure sensor. However, as described above, in Patent Documents 1 and 2, it is determined that there is an abnormality only when the difference between the detection values of the atmospheric pressure sensor and the intake pressure sensor exceeds a predetermined threshold. Therefore, when the detection accuracy of the pressure sensor gradually decreases, the engine is continuously controlled using the detection value whose detection accuracy has decreased until the pressure sensor is determined to be abnormal. Here, the pressure such as the intake pressure is one of the important state values when controlling the engine, and when the engine is controlled using the intake pressure or the like with reduced detection accuracy, the engine performance can be sufficiently exhibited. It may disappear.

  Further, in order to reduce the amount of calculation of the process of determining the fuel injection amount and the ignition timing based on the two state values of the atmospheric pressure and the intake pressure, Patent Document 3 combines the two state values into one state value. It is just one of them. Therefore, Patent Document 3 does not disclose a technique for correcting a decrease in detection accuracy of a pressure sensor.

  The present invention has been made in view of the above circumstances, and its main object is to use pressure by correcting the lowered detection accuracy even if the detection accuracy of the pressure sensor is gradually decreased. To provide an engine capable of executing control.

Means and effect for solving the problem

  The problem to be solved by the present invention is as described above, and next, means for solving the problem and its effect will be described.

According to an aspect of the present invention, an engine having the following configuration is provided. That is, the engine includes a first pressure sensor, a second pressure sensor, and a control unit. The first pressure sensor is an atmospheric pressure sensor that detects an atmospheric pressure during engine operation as a first detection value. The second pressure sensor is disposed at a position different from the first pressure sensor, and detects a pressure of intake or exhaust as a second detection value. The control unit performs engine control. The control unit detects the first detection value and the second detection value before starting the engine after power is supplied to the first pressure sensor and the second pressure sensor, and A shift amount which is a difference between the second detection value and one detection value is obtained, and the second detection value detected during engine operation is offset and corrected so as to eliminate the shift amount .

Thereby, even if the second pressure sensor is deteriorated due to the use environment and the passage of time and the pressure detection accuracy is lowered, the second pressure sensor is corrected by obtaining the amount of displacement as described above, It is possible to suppress a decrease in detection accuracy of the second pressure sensor. Therefore, the engine can be controlled using more accurate intake pressure or exhaust pressure or the like. In addition, the first pressure sensor is an atmospheric pressure sensor, and the atmospheric pressure sensor is less likely to deteriorate as compared to other pressure sensors that are in contact with high-pressure intake gas or high-temperature exhaust gas. By correcting the pressure sensor, the error of the second pressure sensor can be largely suppressed (to the extent of the first pressure sensor). Further, by obtaining the amount of deviation at the above timing, the pressure of each part of the engine is approximately equal to the atmospheric pressure before starting the engine, so by measuring the pressure at this timing, the second detection value for the first detection value The amount of deviation can be accurately grasped.

The engine includes a plurality of second pressure sensors, and the control unit determines whether the absolute value of the amount of deviation is equal to or more than a predetermined threshold value for each of the second pressure sensors. In the case where the absolute value of the displacement amount is equal to or greater than a predetermined threshold value for at least one of the second pressure sensors, it is preferable to notify an abnormality and prohibit engine start.

In the engine, the plurality of second pressure sensors are provided, and the control unit obtains the amount of deviation for each of the second pressure sensors, and the second detection value of each of the plurality of second pressure sensors so as to eliminate the amount of deviation. It is preferable to offset and correct.

In the engine described above, the first pressure sensor is preferably attached to the control unit.

  In general, since the control unit is composed of a large number of substrates and the like, the control unit is provided at a position where heat and vibration are not easily transmitted. Therefore, the atmospheric pressure sensor disposed in the control unit is less likely to deteriorate as compared with other pressure sensors. Therefore, by correcting the second pressure sensor based on the atmospheric pressure sensor, the error of the second pressure sensor can be largely suppressed (to the level of the atmospheric pressure sensor).

The schematic plan view of an engine. Explanatory drawing which shows typically the flow of gas, and various sensors. The graph which shows the result of the experiment which measured various pressure values using the pressure sensor of the new article and the pressure sensor which deteriorated by prolonged use. The flowchart which shows the process which correct | amends the detection value of the pressure sensor which detection accuracy fell, and controls an engine. The graph which shows the outline of the processing which amends the detection value of other pressure sensors, when the shift amount of the detection value of other pressure sensors to atmospheric pressure sensor is smaller than a threshold. The graph which shows the state in case the deviation | shift amount of the detected value of the other pressure sensor with respect to an atmospheric pressure sensor is more than a threshold value.

  Next, embodiments of the present invention will be described with reference to the drawings. The engine 100 is a diesel engine and is mounted on a working machine, a ship, and the like.

  First, the outline of the engine 100 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the engine 100 includes an intake pipe 20, a supercharger 21, a supercharger pipe 24, an intake manifold 26, and a breather hose 27 as members of an intake system.

  The suction pipe 20 sucks in gas from the outside. The suction pipe 20 is provided with a filter for removing dust and the like in the gas.

  The supercharger 21 includes a turbine 22 and a compressor 23 as shown in FIG. The turbine 22 is disposed inside the exhaust pipe 31 and configured to rotate using exhaust gas. The compressor 23 is disposed inside the connection point between the suction pipe 20 and the supercharging pipe 24, is connected to the same shaft 21 a as the turbine 22, and rotates as the turbine 22 rotates. The supercharger 21 can compress air and forcibly take in air by rotation of the compressor 23.

  The supercharging pipe 24 supplies the gas sucked by the supercharger 21 to the intake manifold 26. The intake manifold 26 divides the gas supplied from the supercharging pipe 24 into a number (four in the present embodiment) corresponding to the number of cylinders and supplies the divided gas to the cylinder head 10. A cylinder head cover 11 and an injector (fuel injection device) 12 are disposed in the cylinder head 10. The injector 12 is controlled by an ECU (engine control unit, control unit) 50 shown in FIG. Since the ECU 50 is provided with a large number of electronic devices weak to heat and vibration, the ECU 50 is disposed at a position where heat and vibration are not easily transmitted.

  The injector 12 injects fuel into the combustion chamber at a predetermined timing. Specifically, the injector 12 is configured to perform main injection near the top dead center (TDC). Further, the injector 12 can perform pre-injection for noise reduction immediately before the main injection, or can perform pilot injection for NOx reduction and noise reduction at a timing before the pre-injection. Also, the injector 12 performs after injection for the purpose of reduction of PM and purification of exhaust gas and temperature rise immediately after main injection, or post injection for the purpose of temperature rise at a timing after the after injection, etc. You can do

  Power can be generated by thus injecting fuel and driving the piston. In the combustion chamber, blow-by gas, exhaust gas and the like are generated by burning the fuel. The breather hose 27 supplies blow-by gas generated in the combustion chamber to the suction pipe 20. This can prevent the unburned gas from being discharged to the outside.

  Further, as shown in FIG. 2, an intake pressure sensor (second pressure sensor) 51 and an intake temperature sensor 52 are attached to the intake manifold 26.

  The intake pressure sensor 51 detects the pressure (intake pressure) of the gas in the intake manifold 26 and outputs the pressure to the ECU 50. The intake air temperature sensor 52 detects the temperature of the gas in the intake manifold 26 and outputs it to the ECU 50. The intake pressure sensor 51 and the intake temperature sensor 52 may be disposed not in the intake manifold 26 but in a pipe or the like upstream therefrom.

  The engine 100 includes an exhaust manifold 30, an exhaust pipe 31, and an exhaust gas purification device 32 as members of the exhaust system. The exhaust gas purification device 32 may be disposed at a position slightly apart from the engine 100.

  The exhaust manifold 30 collectively supplies the exhaust gas generated in the plurality of combustion chambers to the turbine 22 of the supercharger 21. Further, an exhaust pressure sensor (second pressure sensor) 53 and an exhaust temperature sensor 54 are attached to the exhaust manifold 30.

  The exhaust pressure sensor 53 detects the pressure (exhaust pressure) of the gas in the exhaust manifold 30 and outputs the pressure to the ECU 50. The exhaust temperature sensor 54 detects the temperature of the gas in the exhaust manifold 30 and outputs the temperature to the ECU 50.

  Part of the gas that has passed through the exhaust manifold 30 is supplied to the EGR device 40 via the EGR pipe 41, and the rest is supplied to the exhaust gas purification device 32 via the exhaust pipe 31.

  The engine 100 also includes an EGR device 40. The EGR device 40 includes an EGR cooler 42 and an EGR valve 43. The EGR cooler 42 cools the exhaust gas. The EGR device 40 can change the amount of exhaust gas supplied to the intake manifold 26 by adjusting the opening degree of the EGR valve 43. The opening degree of the EGR valve 43 is controlled by the ECU 50. The ECU 50 adjusts the opening degree of the EGR valve 43 based on, for example, the differential pressure between the intake pressure and the exhaust pressure.

  The exhaust gas purification device 32 purifies and discharges the exhaust gas. The exhaust gas purification device 32 includes an oxidation catalyst 33 and a filter 34. The oxidation catalyst 33 is made of platinum or the like, and is a catalyst for oxidizing (burning) unburned fuel, carbon monoxide, nitrogen monoxide and the like contained in the exhaust gas. The filter 34 is configured, for example, as a wall flow type filter, and collects PM (particulate matter) contained in the exhaust gas treated with the oxidation catalyst 33.

  In addition, an oxidation catalyst temperature sensor 55, a filter temperature sensor 56, and a differential pressure sensor (second pressure sensor) 57 are attached to the exhaust gas purification device 32. The oxidation catalyst temperature sensor 55 detects the temperature in the vicinity of the inlet of the exhaust gas purification device 32 (the exhaust upstream side of the oxidation catalyst 33). The filter temperature sensor 56 detects the temperature between the oxidation catalyst 33 and the filter 34 (upstream of the filter 34). The temperatures detected by the oxidation catalyst temperature sensor 55 and the filter temperature sensor 56 are collectively referred to as a purifier temperature.

  The differential pressure sensor 57 is a sensor for detecting a pressure difference between the upstream side and the downstream side of the filter 34. The ECU 50 calculates the amount of PM deposited on the filter 34 based on the detection result of the differential pressure sensor 57. As a method of calculating the PM deposition amount, in addition to using the differential pressure, the oxidation reaction that occurs in the exhaust gas purification device 32 can be calculated based on the operation history of the engine 100 and the like, and the PM deposition amount can also be obtained based thereon. . The pressure on the upstream side of the filter 34 detected by the differential pressure sensor 57 is also used when calculating the intake amount or the exhaust amount by calculation.

  Further, as shown in FIG. 2, the engine 100 is provided with an atmospheric pressure sensor (first pressure sensor) 58. The atmospheric pressure sensor 58 is attached to the case of the ECU 50, and outputs the detected atmospheric pressure to the ECU 50.

  Next, with reference to FIGS. 3 to 6, the decrease in detection accuracy of various pressure sensors provided in the engine 100 and the process for correcting the same will be described.

  First, the deterioration tendency of a general pressure sensor will be described. FIG. 3 is a graph showing the results of experiments in which various pressure values were measured using a new pressure sensor and a pressure sensor that deteriorated due to long-term use. The horizontal axis of FIG. 3 indicates the pressure, and the vertical axis indicates the voltage (output voltage) output by the pressure sensor according to the detected pressure. The pressure sensor outputs a higher output voltage as the detected pressure increases.

  As shown in the graph of FIG. 3, although the output voltage of the pressure sensor after being used for a long time is smaller than the output voltage of a new pressure sensor, the slope of the graph does not change much. In other words, it can be expressed that the graph showing the relationship between the output voltage and the pressure is offset to the lower side (the low side of the output voltage) as it is used for a long time.

  In consideration of the deterioration tendency of the pressure sensor, in the present embodiment, a process of correcting the pressure sensor whose detection accuracy is reduced due to long-term use or the like is performed. The process of correcting the pressure sensor will be specifically described below with reference to the flowchart of FIG. Note that the flowchart shown in FIG. 4 is an example, and processing may be added, changed, or deleted.

  When the user operates an ignition key or the like, the power supply (main switch) is turned on to activate components of the electrical system (the ECU 50 and various sensors). After the activation is completed (S101), the ECU 50 acquires detection values of the atmospheric pressure sensor 58, the intake pressure sensor 51, the exhaust pressure sensor 53, and the differential pressure sensor 57 (S102). As for the differential pressure sensor 57, the pressure on the upstream side of the filter 34 is acquired.

  Although the specific method for acquiring the pressure is arbitrary, it is preferable to acquire the pressure after a predetermined time has elapsed since the detected value may vary immediately after the pressure sensor is activated. Moreover, since the pressure fluctuates due to the influence of noise or the like, it is more preferable to use an average value of a predetermined period.

  Here, since the engine 100 has not been started yet, all pressure sensors are under atmospheric pressure. Therefore, by comparing the detection values of the pressure sensors, it is possible to determine the relative displacement amount of the pressure sensors. In general, pressure sensors deteriorate quickly when used under high temperature or high pressure. Therefore, the atmospheric pressure sensor 58 disposed at normal temperature and atmospheric pressure is more deteriorated than the intake pressure sensor 51 disposed at high pressure, the exhaust pressure sensor 53 disposed at high temperature, and the differential pressure sensor 57 It is thought that it does not do. In particular, since the atmospheric pressure sensor 58 of the present embodiment is attached to the ECU 50, it is not easily affected by vibration, so that the progress of deterioration can be further suppressed.

  Therefore, in the present embodiment, the amount of displacement of another pressure sensor is determined based on the detection value of the atmospheric pressure sensor 58. In the following description, the intake pressure sensor 51, the exhaust pressure sensor 53, and the differential pressure sensor 57 may be collectively referred to as "(other) pressure sensor". The ECU 50 subtracts the detection value of the atmospheric pressure sensor 58 from the detection value of another pressure sensor to obtain the amount of deviation of each pressure sensor (S103). Generally, the amount of deviation is a negative value, since a deteriorated pressure sensor generally detects a lower pressure.

  Next, the ECU 50 determines, for each pressure sensor, whether the absolute value of the amount of deviation is equal to or greater than a predetermined threshold (S104). The ECU 50 permits the start of the engine 100 when the absolute value of the amount of deviation is smaller than the threshold (for example, in the case shown in FIG. 5) for all pressure sensors (S105).

  On the other hand, when the absolute value of the displacement amount is equal to or greater than a predetermined threshold (for example, as shown in FIG. 6), the ECU 50 reports that there is an abnormality in the corresponding pressure sensor (S108). . Although the notification method is arbitrary, for example, it is conceivable to display that on a display or to sound an alarm.

  Here, when the deterioration of the pressure sensor has considerably progressed, the case where the pressure sensor is broken, the case where the cable connecting the pressure sensor and the ECU 50 is broken, etc. can be considered as the occurring abnormality. Since it is considered that appropriate control can not be performed if the engine 100 is started in this state, the ECU 50 prohibits the start of the engine (S109).

  When the start of the engine 100 is permitted by the process of step S105, the ECU 50 corrects each pressure sensor so as to eliminate the calculated amount of deviation. Although the amount of displacement obtained in step S103 is the amount of displacement under atmospheric pressure, as shown in FIG. 3 and the like, the inclination does not change significantly even if the pressure sensor is degraded. By subtraction, a detection value after correction is obtained (S106). Since the amount of displacement is obtained for each pressure sensor, the detected value of the corresponding pressure sensor is corrected using the amount of displacement obtained for each pressure sensor.

  Further, the process of subtracting the amount of deviation and correcting the detection value of the pressure sensor is always performed regardless of the pressure detected by the pressure sensor. Therefore, as shown in FIG. 5, a value obtained by offsetting the detection value before correction to the one where the output voltage (ie, the pressure to be detected) becomes larger corresponds to the detection value after correction.

  During operation of the engine 100, the ECU 50 controls the engine using the corrected detection value (S107). By performing the above processing, even in a situation where the amount of displacement of the pressure sensor is small and it is not enough to notify an abnormality, the engine 100 can be controlled using the pressure obtained by correcting the amount of displacement.

  Specifically, the ECU 50 calculates the weight of air supplied from the outside, the weight of gas supplied by the EGR device 40, and the like based on the intake pressure, the exhaust pressure, the temperature of each part, and the like. Accordingly, the ECU 50 controls, for example, the opening degree of the EGR valve 43 of the EGR device 40.

  In addition, when the pressure sensor is deteriorated, as shown in FIG. 3, the inclination of the graph showing the relationship between the pressure and the output voltage also slightly changes, so an error (detected using a new product is detected as the value deviates from the atmospheric pressure) The difference between the However, the pressure mainly detected by the engine 100 is about 100 kPa (about atmospheric pressure) to about 150 kPa, and a value far away from the atmospheric pressure is not detected, so sufficient correction accuracy can be maintained even with the correction method of this embodiment. .

  Further, in the present embodiment, the amount of displacement of the pressure sensor with respect to the atmospheric pressure sensor 58 is obtained, and the correction can be performed only by adding the amount of displacement. Therefore, the correction can be performed by a very simple method. Therefore, the processing amount of the ECU 50 can be suppressed.

  As described above, in the present embodiment, processing for obtaining the displacement amount of the pressure sensor is performed immediately before starting the engine 100. Thus, the amount of deviation can be calculated according to the situation immediately before the pressure sensor is used, so that the amount of deviation can be accurately obtained. In addition, the process which calculates | requires the gap | deviation amount of a pressure sensor can also be performed at another timing. For example, the amount of displacement of the pressure sensor may be obtained after the engine 100 has stopped and the time for the pressure in the engine 100 to reach the atmospheric pressure has elapsed. In this case, since it is not necessary to perform the process of FIG. 4 when starting the engine 100, the time until the engine 100 is started can be shortened.

  As described above, the engine 100 according to this embodiment includes the atmospheric pressure sensor 58, another pressure sensor, and the ECU 50. An atmospheric pressure sensor 58 detects atmospheric pressure. Another pressure sensor is disposed at a position different from the atmospheric pressure sensor 58 and detects the pressure at a predetermined position of the engine 100. The ECU 50 detects the detection value (second detection value) of the other pressure sensor with respect to the detection value (first detection value) of the atmospheric pressure sensor 58 at the timing when the atmospheric pressure sensor 58 and the other pressure sensors detect the atmospheric pressure. The pressure value detected by another pressure sensor while the engine 100 is operating is corrected so as to eliminate the amount of deviation.

  As a result, even if another pressure sensor is deteriorated due to the use environment, the passage of time, etc. and the pressure detection accuracy is lowered, the deviation amount is determined as described above to correct the other pressure sensor, It is possible to suppress the decrease in detection accuracy of other pressure sensors. Therefore, engine 100 can be controlled using more accurate intake pressure or exhaust pressure or the like.

  Further, in the engine 100 of the present embodiment, the atmospheric pressure sensor 58 is an atmospheric pressure sensor that detects the atmospheric pressure during operation of the engine 100.

  As a result, the atmospheric pressure sensor 58 is less likely to deteriorate as compared with the intake pressure sensor 51 touching a high pressure intake gas, the exhaust pressure sensor 53 touching a high temperature exhaust gas, and the differential pressure sensor 57. By correcting the other pressure sensors, the errors of the other pressure sensors can be largely suppressed (up to about the atmospheric pressure sensor 58).

  Further, in the engine 100 of the present embodiment, the atmospheric pressure sensor 58 is attached to the ECU 50.

  Generally, since the ECU 50 is composed of a large number of substrates and the like, the ECU 50 is provided at a position where heat and vibration are not easily transmitted. Therefore, the atmospheric pressure sensor disposed in the ECU 50 is less likely to deteriorate as compared with other pressure sensors. Therefore, by correcting the other pressure sensors based on the atmospheric pressure sensor, errors of the other pressure sensors can be largely suppressed (to the level of the atmospheric pressure sensor).

  Further, in the engine 100 of the present embodiment, the ECU 50 detects the power from the atmospheric pressure sensor 58 and the other pressure sensors before the engine 100 is started after the power is supplied to the atmospheric pressure sensor 58 and the other pressure sensors. Get the value.

  Thereby, since the pressure of each part of engine 100 is approximately equal to the atmospheric pressure before the start of engine 100, by measuring the pressure at this timing, the deviation of the detection value of the other pressure sensor from the detection value of atmospheric pressure sensor 58 The amount can be accurately grasped.

  Further, in the engine 100 of the present embodiment, the ECU 50 reports an abnormality of another pressure sensor when the amount of deviation of the detection value of the other pressure sensor from the detection value of the atmospheric pressure sensor 58 is equal to or greater than a predetermined threshold. .

  As a result, it is possible to notify the user that some other pressure sensor has failed.

  The preferred embodiment of the present invention has been described above, but the above-described configuration can be modified, for example, as follows.

  In the above embodiment, the pressure serving as a reference when correcting the pressure sensor is a detection value of the atmospheric pressure sensor 58. However, detection values other than the atmospheric pressure sensor 58 may be used as the reference pressure.

  In the above embodiment, the atmospheric pressure sensor 58 is attached to the case of the ECU 50, but may be attached to another position.

  In the above embodiment, the amount of deviation is calculated by subtracting the detection value of the atmospheric pressure sensor from the detection value of the intake pressure sensor 51 etc. However, the detection value of the intake pressure sensor 51 etc. is subtracted from the detection value of the atmospheric pressure sensor The value may be a shift amount (basically, a positive value). In this case, when the correction is performed, the detection value after correction is calculated by adding the deviation amount to the detection value of the intake pressure sensor 51 or the like.

  When the engine 100 is restarted immediately after stopping, there is a possibility that the pressure around the intake pressure sensor 51, the exhaust pressure sensor 53, etc. is not yet at atmospheric pressure. In this case, since it is not possible to obtain an accurate amount of displacement, the detection value of the intake pressure sensor 51 or the like may be corrected using the correction amount used before the engine 100 is stopped.

26 intake manifold 30 exhaust manifold 32 exhaust gas purification device 33 oxidation catalyst 34 filter 50 ECU
51 Intake pressure sensor (second pressure sensor)
53 Exhaust pressure sensor (second pressure sensor)
57 Differential pressure sensor (second pressure sensor)
58 Atmospheric pressure sensor (1st pressure sensor)
100 engines

Claims (4)

A first pressure sensor that is an atmospheric pressure sensor that detects an atmospheric pressure during engine operation as a first detection value;
A second pressure sensor disposed at a position different from the first pressure sensor and detecting a pressure of intake or exhaust as a second detection value;
A control unit that performs engine control ;
Equipped with
The control unit detects the first detection value and the second detection value before starting the engine after power is supplied to the first pressure sensor and the second pressure sensor, and An engine characterized in that a shift amount which is a difference between the second detection value and one detection value is determined, and the second detection value detected during engine operation is offset and corrected so as to eliminate the shift amount. . The engine according to claim 1, wherein
A plurality of the second pressure sensors are provided,
The control unit
For each of the second pressure sensors, it is determined whether the absolute value of the amount of deviation is equal to or greater than a predetermined threshold value,
An engine, comprising: at least one of the second pressure sensors, configured to notify an abnormality and prohibit engine start when an absolute value of the displacement amount is equal to or greater than a predetermined threshold value. The engine according to claim 1 or 2,
A plurality of the second pressure sensors are provided,
The control unit
An engine characterized in that the amount of displacement is determined for each of the second pressure sensors, and each of the second detection values is offset and corrected so as to eliminate the amount of displacement. The engine according to any one of claims 1 to 3 , wherein
The first pressure sensor is attached to the control unit.

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