JPH11257085A - Failure diagnostic method of supercharger controller system in internal combustion engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve diagnostic accuracy in diagnosing a supercharger controller system of an internal combustion engine with a supercharger. SOLUTION: This invention increases the engine speed NE under deck pressure constant control by operating a power lever of an internal combustion engine for aircraft. When the deck pressure PD reaches the target deck pressure Pda, operation of the power lever is stopped (step 102). The engine speed NE is increased only a predetermined number of revolutions γ (step 104) as far as the engine speed NE is within the predetermined range (step 103). Even if the engine speed changes, if the deck pressure PD settles to the target deck pressure Pda, the supercharger controller system can be judged normal (step 106). If it does not settle, it can be judged abnormal (step 107).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing a failure of an internal combustion engine with a turbocharger before actual operation.

[0002]

2. Description of the Related Art In an internal combustion engine with a supercharger for an aircraft, for example, the inlet air condition of the supercharger compressor changes according to the flight altitude, and therefore, the supercharging pressure is controlled in accordance with the flight altitude. In the supercharging pressure control of an internal combustion engine with a supercharger for an aircraft, generally, at an altitude lower than the critical altitude, control for maintaining the compressor outlet pressure constant (supercharging pressure constant control) is performed. At a high altitude, control is performed to keep the pressure ratio between the compressor outlet pressure and the inlet pressure constant (pressure ratio constant control).

[0003] In an aircraft equipped with a supercharged internal combustion engine, a so-called preflight check is performed on the ground before flight for safe operation, and various types of control such as fuel control, ignition control, and supercharging pressure control are performed. It is diagnosed whether or not the control is normally performed.

[0004] Here, the preflight check for the supercharging pressure control system is performed under the supercharging pressure constant control because all airports on the earth are located at a position lower than the critical altitude. In the preflight check for the conventional boost pressure control, the engine speed of the internal combustion engine is increased to a test speed near the maximum speed, and the boost pressure is maintained at a predetermined target boost pressure in the operating state at the test speed. Diagnosis was based on whether or not it was done.

[0005] An example of a failure diagnosis in such a supercharging pressure control system is disclosed in, for example, JP-A-61-152927.
Is disclosed in Japanese Patent Application Laid-Open Publication No. HEI 9-203 (1995).

[0006]

Since the conventional method for diagnosing a failure of the supercharging pressure control system is performed in an operating state in which the engine speed is increased to near the maximum speed, the internal combustion engine is liable to overheat. However, there is a problem that noise is also increased. In addition, during this diagnosis, the thrust of the body is controlled by the brake, so that the load on the brake and the like increases, which is not preferable.

[0007] In addition, since the diagnosis is made based only on the result of the operation state at one point, the test rotational speed,
In the unlikely event of a waste gate valve for boost pressure control,
If the failure has occurred at the opening at which the target boost pressure is reached at the test rotation speed, there is a risk that a false diagnosis is made that the supercharging pressure control system is functioning normally.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and the problem to be solved by the present invention is that diagnosis can be made at a relatively low engine speed and reliability can be improved. To obtain a method for diagnosing a supercharged pressure control system with high reliability.

[0009]

The present invention has the following features to attain the object mentioned above. (1) The present invention relates to a failure diagnosis method for a supercharging pressure control system that controls a supercharging pressure to be equal to a target supercharging pressure by adjusting an opening of a waste gate valve of a supercharged internal combustion engine. First, the engine speed is maintained at a predetermined speed in a rotation region where the supercharging pressure becomes a target supercharging pressure, and then the engine speed is changed by a predetermined amount, and the supercharging pressure after the engine speed changes and the target When the difference from the supercharging pressure is within a predetermined allowable range, the supercharging pressure control system is determined to be normal, and when the difference is out of the allowable range, it is determined to be abnormal. 1 is a failure diagnosis method for a supercharging pressure control system in an engine-equipped internal combustion engine.

In a supercharging pressure control system that controls the supercharging pressure to be equal to the target supercharging pressure, if the system is functioning normally, the supercharging pressure is maintained at the target supercharging even if the engine speed is changed. It converges on the supply pressure. Therefore, if the supercharging pressure does not converge to the target supercharging pressure after changing the engine speed, it can be determined that there is an abnormality in the system.

When changing the engine speed, the engine speed may be increased or the engine speed may be reduced. However, when reducing the engine speed, the engine speed after the change must be in a rotation range controlled to the target boost pressure.

The method for diagnosing a failure of the supercharging pressure control system can be performed in a relatively low engine speed region near the intercept speed, so that the load applied to the internal combustion engine can be reduced and the safety can be improved. high.

(2) The present invention provides a failure diagnosis of a supercharging pressure control system for controlling a supercharging pressure to be equal to a target supercharging pressure by adjusting an opening of a waste gate valve of an internal combustion engine with a supercharger. In the method, a first target boost pressure in a normal engine operating state and a second target boost pressure for diagnosis having a value different from the first target boost pressure are set and switched. The target supercharging pressure is set so that either one of the first target supercharging pressure and the second target supercharging pressure can be selected, and the switching means is switched to switch the respective target supercharging pressures. The operation is selected, and it is determined whether or not the actual supercharging pressure converges to the target value with respect to the selected target supercharging pressure. Pressure control system for a supercharged internal combustion engine This is a failure diagnosis method.

In a supercharging pressure control system for controlling the supercharging pressure to be equal to the target supercharging pressure, if the system is functioning normally, the target supercharging pressure is set to the first target supercharging pressure. The supercharging pressure converges to the first target supercharging pressure when the supercharging is performed, and the supercharging pressure converges to the second target supercharging pressure when the target supercharging pressure is set to the second target supercharging pressure. I do. Therefore, if the actual boost pressure does not converge to the selected target boost pressure even though the target boost pressure is changed, it can be determined that there is an abnormality in the system.

The method for diagnosing a failure of the supercharging pressure control system can be performed in a relatively low engine speed region near the intercept speed, so that the load applied to the internal combustion engine can be reduced and the safety can be improved. high.

The second target supercharging pressure can be set smaller than the first target supercharging pressure, or can be set larger than the first target supercharging pressure. However, in consideration of the load on the internal combustion engine and safety, it is preferable that the second target boost pressure is set to be smaller than the first target boost pressure.

The initially set target boost pressure may be either the first target boost pressure or the second target boost pressure. Further, before switching the target supercharging pressure by the switching means, the engine speed may be kept constant. With this configuration, when the engine speed is kept constant, the boost pressure is also kept constant, so that the behavior of the boost pressure after switching the target boost pressure can be clearly confirmed, and diagnostic accuracy is improved.

The failure diagnosis method for the supercharging pressure control system according to the above (1) and (2) can be applied to a supercharging pressure control system for an internal combustion engine for an aircraft or an internal combustion engine for a vehicle.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for diagnosing a failure of a supercharging pressure control system for an internal combustion engine according to the present invention will be described below with reference to FIGS.

[First Embodiment] First, the configuration of a supercharged internal combustion engine to be diagnosed will be described with reference to FIG. The internal combustion engine in this embodiment is an aspect of an internal combustion engine with a turbocharger for an aircraft.

In FIG. 1, reference numeral 1 indicates an internal combustion engine, and reference numeral 2
Denotes a propeller driven by the internal combustion engine 1. In this embodiment, a multi-cylinder (V-type, eight-cylinder in FIG. 1) four-cycle reciprocating engine is used as the internal combustion engine 1. In FIG. 1, reference numeral 5 denotes an intake manifold that connects intake ports of respective cylinders of the internal combustion engine 1 to a common intake duct 6. A fuel injection valve 7 that injects pressurized fuel to the intake port of each cylinder is disposed near the intake port connection portion of each cylinder of the intake manifold 5.

Reference numeral 11 denotes a throttle valve arranged in the intake duct 6 downstream of the intercooler 8. The throttle valve 11 is connected to a power lever 12 provided in a cockpit, and has an opening corresponding to the operation amount of the power lever 12.

Reference numeral 10 denotes an exhaust turbocharger (supercharger) comprising a centrifugal compressor 16 and a centrifugal exhaust turbine 20 for driving the compressor 16, and reference numeral 9 denotes a discharge port 15 of the compressor 16 and an intercooler. FIG.

Reference numerals 21 and 22 denote exhaust manifolds that connect the exhaust ports of the respective cylinders of the banks on both sides of the internal combustion engine 1 to a common exhaust pipe 23. The common exhaust pipe 23 is connected to the exhaust inlet 17 of the exhaust turbine 20 of the turbocharger 10.

The intake air of the internal combustion engine 1 flows from an air cleaner (not shown) through an intake pipe 13 to the compressor 1.
6, and becomes boosted supercharged air to form an intake duct 9.
After being cooled by the intercooler 8, the air is supplied to each cylinder of the internal combustion engine 1 through the intake duct 6, the throttle valve 11, and the intake manifold 5.

The exhaust gas of the internal combustion engine 1 passes through the exhaust pipes 23 from the exhaust manifolds 21 and 22 and flows into the turbine 20 through the exhaust inlet 17. After the turbine 20 and the compressor 16 connected thereto are driven to rotate, the exhaust gas is exhausted. Outlet pipe 1
It is discharged from 9.

Exhaust pipe 23 and exhaust outlet pipe 1 of turbine 20
9 is connected by an exhaust bypass passage 24 that bypasses the exhaust turbine 20. In the exhaust bypass passage 24, the exhaust turbine 20
Gate valve (hereinafter abbreviated as WGV) 26 that controls the flow rate of exhaust gas flowing to exhaust outlet pipe 19 by bypassing exhaust gas.
Is provided. When the WGV 26 is fully closed, almost the entire amount of exhaust gas from the internal combustion engine 1 flows into the turbine 20, so that the rotation speed of the turbocharger 10 increases and the outlet pressure (supercharging pressure) of the compressor 16 increases. On the other hand, WGV2
When the valve 6 is opened, part of the exhaust gas of the internal combustion engine 1
, And flows into the exhaust outlet pipe 19, so that the flow rate of the exhaust gas passing through the turbine 20 decreases. As a result, the rotation speed of the turbocharger 10 decreases, and the supercharging pressure decreases according to the opening of the WGV 26. That is, by adjusting the opening of the WGV 26, the supercharging pressure of the turbocharger 10 can be reduced to a desired level.

Reference numeral 25 denotes an actuator for driving the WGV 26 to open and close. The actuator 25 operates in response to a command signal from an engine control device (EEC) 30 described later, and controls the WGV 26 to an opening corresponding to the command signal from the EEC 30. In addition, as the actuator 25,
As long as the WGV 26 can be driven to an opening in accordance with a command signal from the EEC 30, any known motor such as a DC motor with a servo mechanism, a stepper motor,
A hydraulic actuator or the like may be used.

In this embodiment, the propeller 2 driven by the internal combustion engine 1 is a variable pitch propeller, and includes a propeller governor 31 for controlling the propeller pitch of the propeller 2. In this embodiment, the propeller governor 31 is a centrifugal governor, and is connected to the drive shaft of the propeller 2 via a rotation transmission shaft (not shown). The propeller governor 31 operates to adjust the propeller pitch so that the engine speed (propeller speed) matches the set speed. That is, when the propeller rotation speed becomes higher than the set rotation speed, the propeller governor 31 increases the propeller pitch and decreases the engine rotation speed by increasing the absorption horsepower of the propeller 2. When the propeller speed is lower than the set speed, the propeller governor 31 reduces the propeller pitch and decreases the absorption horsepower of the propeller 2 to increase the engine speed. As a result, the propeller speed (engine speed) is controlled to match the set speed of the propeller governor 31.

In this embodiment, the propeller governor 3
1 is a common power lever 12 together with a throttle valve 11
By operating a single power lever 12, both the opening of the throttle valve 11 (engine output) and the engine speed (pitch of the propeller 2) can be controlled simultaneously. . Therefore, the throttle valve 1
1 and the control cable of the propeller governor 31 are connected to the power lever 1 via cams each having a shape corresponding to the characteristics of the fuselage.
2 and the operation amount change characteristics of the throttle valve 11 and the throttle governor 31 with respect to the operation amount of the power lever 12 are set to appropriate characteristics, respectively, so that an optimum engine output / rotation speed characteristic according to the body characteristics is obtained. It can be set in advance.

FIG. 2 shows a control device (EEC: electric engine controller) 30 for controlling the internal combustion engine 1.
FIG. 3 is a diagram showing the configuration of FIG. In this embodiment, as shown in FIG. 2, the EEC 30 is a microcomputer having a known configuration in which a RAM, a ROM, a CPU, an input port, and an output port are mutually connected by a bidirectional bus.
In this embodiment, the EEC 30 performs basic control such as fuel injection control and ignition timing control of the internal combustion engine 1 and also performs supercharging pressure control of a turbocharger 10 described later.
For these controls, an input port of the EEC 30 receives a rotational speed NE of the internal combustion engine 1 from a rotational speed sensor (NE sensor) 32 provided on a crankshaft (not shown) of the internal combustion engine 1.
Is input. EEC30 C
The PU calculates the engine speed NE based on the pulse signal and uses it for various controls described later.

An input port of the EEC 30 has an intake pressure sensor (PM sensor) 33 provided in the intake duct 6 downstream of the throttle valve 11 and a deck pressure sensor provided in the intake duct 6 upstream of the throttle valve 11. Sensor (PD
Sensor) 34, an electric signal corresponding to the absolute pressure PM in the intake duct 6 and the deck pressure PD of the turbocharger 10.
An electric signal corresponding to (absolute pressure) is input via the AD converter 67. Further, a voltage signal corresponding to the opening TH of the throttle valve 11 is input to the input port of the EEC 30 from the throttle valve opening sensor (TH sensor) 35 provided near the throttle valve 11 via the AD converter 67. In addition, an atmospheric temperature sensor (TA sensor) 37 and an atmospheric pressure sensor (PA sensor) 36 disposed in the intake inlet pipe 13 of the turbocharger compressor 16.
Therefore, voltage signals corresponding to the atmospheric temperature TA and the atmospheric pressure PA are input via the AD converter 67.

The output port of the EEC 30 is connected to the ignition plug 4 and the fuel injection valve 7 of each cylinder of the internal combustion engine 1 via an ignition circuit 68 and a drive circuit 69, respectively. Timing and ignition timing are controlled. In this embodiment, the EEC 30 is a PM sensor 33
Pressure P detected by the sensor and the NE sensor 32, respectively.
Based on M and the engine speed NE, the optimum fuel injection amount, injection timing, and ignition timing are determined from a numerical table stored in the ROM in advance, and fuel injection and ignition are performed based on these.

The output port of the EEC 30 is further connected to the actuator 25 of the WGV 26 via a drive circuit 69, and controls the supercharging pressure by adjusting the opening of the WGV 26.

In the aircraft internal combustion engine 1, two supercharging pressure control methods are selectively used according to altitude. That is, below the critical altitude, control is performed to maintain the compressor outlet pressure (supercharging pressure) constant (supercharging pressure constant control). When the pressure exceeds the critical altitude, the pressure ratio between the compressor outlet pressure and the inlet pressure is reduced. Control for keeping the pressure constant (pressure ratio constant control) is performed. Since a preflight check to be described later is literally performed on the ground before the flight, the preflight check is performed under constant boost pressure control. In this embodiment, the deck pressure detected by the deck pressure sensor 34 is used as the compressor outlet pressure (supercharging pressure). Control.

In the constant deck pressure control, WG is maintained until the engine speed NE reaches the intercept speed NEi.
V26 is in the fully closed state, and the deck pressure PD gradually increases as the engine speed NE increases. Then, when the engine speed NE reaches the intercept speed NEi, the WGV 26 starts to open in order to keep the deck pressure PD at the target deck pressure PDa. That is, the engine speed NE
Exceeds the intercept rotational speed NEi, EEC30
Outputs a command signal to the WGV actuator 25 so that the deck pressure PD becomes the target deck pressure PDa, and performs feedback control of the opening of the WGV 26. The trend at this time is
As the engine speed NE increases, the opening of the WGV 26 increases.

The constant pressure ratio control is not directly related to the present invention and is also a known technique, so that the description thereof is omitted. Next, a procedure of a failure diagnosis method of the boost pressure control system by a preflight check will be described with reference to a flowchart of FIG.

First, the operator starts the internal combustion engine 1 and operates the power lever 12 to slowly increase the engine speed NE (step 100). Next, the operator looks at the deck pressure indicator (not shown) mounted on the body and determines whether or not the deck pressure PD reaches the target deck pressure PDa (step 101). The target deck pressure PDa here is a target deck pressure for a normal flight.

When the supercharging pressure control system is functioning normally, the engine speed NE becomes equal to the intercept speed NE.
It should reach the target deck pressure PDa in the vicinity of i, in which case the operator determines YES in step 101,
Proceed to step 102. If the deck pressure PD does not reach the target deck pressure PDa even if the engine speed is increased to a predetermined speed higher than the intercept speed NEi, that is, if NO is determined in step 101, the supercharging is performed at that time. Since it can be determined that the pressure control system is abnormal,
The operator proceeds to step 107, determines that there is an abnormality, and ends this routine.

Next, at step 102, when the deck pressure PD reaches the target deck pressure PDa, the operator stops the operation of the power lever 12 and holds the power lever 12 at the stop position. After a lapse of a predetermined time after the operation lever 12 is stopped, the operator looks at a rotation speed indicator (not shown) mounted on the airframe and determines that the engine rotation speed NE is within a predetermined allowable intercept rotation speed range. It is determined whether or not it is within (step 103). This is because the intercept rotational speed NEi differs depending on environmental conditions (altitude and the like), and therefore, the allowable range of the intercept rotational speed (for example, lower limit α = −500 rpm, upper limit A value β = + 500 rpm) is set, and it is determined whether or not the value falls within this range.

If the engine speed NE is within the range of the permissible intercept speed, the operator proceeds to step 103 to make Y
It is determined as ES, and the process proceeds to step 104. Engine speed NE
Is out of the range of the permissible intercept rotation speed, that is, if NO is determined in step 103, it can be determined that the supercharging pressure control system is abnormal at that time, and the operator proceeds to step 107. Is determined as abnormal, and this routine ends.

Next, in step 104, the operator operates the power lever 12 while looking at the rotation speed indicator.
The engine speed NE is changed to a predetermined speed γ (for example, 100 to 200).
rpm).

Then, the operator looks at the deck pressure indicator,
After a lapse of a predetermined time after the engine speed NE is changed in step 104, the deck pressure PD converges to the target deck pressure PDa, and whether or not the difference between the deck pressure PD and the target deck pressure PDa is within a predetermined allowable range. (| PD-PDa | <ε?)
Is determined (step 105).

When the supercharging pressure control system is functioning normally, the deck pressure PD can be increased even if the engine speed NE is increased.
Should converge to the target deck pressure PDa, in which case the operator makes a positive determination in step 105, proceeds to step 106, determines that it is normal, and ends this routine.

On the other hand, even if a predetermined time has passed since the engine speed NE was changed in step 104, the deck pressure P
If D does not converge to the target deck pressure PDa, the operator makes a negative determination in step 105, proceeds to step 107, determines that there is an abnormality, and ends this routine.

FIG. 4 shows the opening of the WGV 26, the engine speed NE, and the deck pressure PD during the preflight check when the supercharging pressure control system is functioning normally.
The transition of is shown.

If the supercharging pressure control system is determined to be abnormal in step 107, the cause of the abnormality is as follows.
If the WGV 26 is stuck and malfunctions,
Defective operation of the GV actuator 25, WGV 26 and W
A malfunction of the linkage connecting the GV actuator 25, a disconnection of the wire harness, a malfunction of the deck pressure sensor 34, a malfunction of the EEC 30, and the like are considered.

As described above, according to the method of diagnosing a failure of the supercharging pressure control system in the first embodiment, the engine speed NE can be implemented in a relatively low speed region near the intercept speed NEi. Internal combustion engine 1
It is excellent in terms of protection and safety. In addition, the deck pressure PD becomes the target deck pressure PDa at a 2-point engine speed NE.
, The accuracy of diagnosis is improved, and the probability of erroneous diagnosis is extremely reduced.

In the above-described first embodiment, the timing at which the power lever 12 is stopped in step 102 (hereinafter referred to as stop timing) is defined as when the engine speed NE reaches the intercept speed NEi. The failure diagnosis method for the boost pressure control system is not limited to the above timing. The stop timing may be any engine speed NE as long as the engine speed NE becomes equal to or more than the intercept speed NEi. If so, step 104
Thus, the engine speed NE can be reduced. However, as described above, from the viewpoint of protection and safety of the internal combustion engine 1, the stop timing is the engine speed NE.
Is preferably in the vicinity of the intercept rotational speed NEi.

In the first embodiment described above, all operations are manually performed by the operator, and the operator looks at the deck pressure indicator and the rotation speed indicator, and determines whether the reading is normal or abnormal based on the reading. Although a judgment is made, a series of operations are automated, and the output signals of the PD sensor and NE sensor are converted to EEC.
At 30, an electrical operation is performed, and steps 101, 103,
It is also possible to make the determination of 105 electronically, display a normal / abnormal display in the cockpit, or sound an abnormal alarm. In this way, the operator only needs to perform an operation of turning on the switch for preflight check.

[Second Embodiment] In the first embodiment, when the engine speed NE is changed without changing the target deck pressure PDa, the deck pressure PD becomes equal to the target deck pressure PDa.
Although the normal / abnormal judgment of the supercharging pressure control system is made based on whether or not the pressure converges to a, the second embodiment changes the target deck pressure PDa to make the actual deck pressure PD This is to determine whether the supercharging pressure control system is normal or abnormal depending on whether or not the vehicle follows.

In this embodiment, by turning on a preflight check switch (hereinafter abbreviated as PFC switch) 38 as a switching means, the target deck pressure becomes the target deck pressure for preflight check (hereinafter, TPD).
P), and by turning off the PFC switch 38, the target deck pressure is set to the target deck pressure for normal flight (hereinafter abbreviated as TPDF). Therefore, in this embodiment, the EEC
ON / OFF of PFC switch 38 to 30 input ports
A signal is input (see FIG. 2). Internal combustion engine 1 and EEC
The other configuration of 30 is the same as that of the above-described first embodiment, and the description is omitted.

First, referring to FIG. 5, the target deck pressure P
The setting procedure of Da will be described. First, step 20
At 0, the EEC 30 determines whether or not the engine speed NE is smaller than a predetermined engine speed ζ. This means that even if the PFC switch 38 is turned on during flight, the target deck pressure P
This is to prevent Da from being set in PTDP,
This is a safety measure aimed at preventing switch malfunction. Here, if a non-flightable engine speed is set as the predetermined engine speed ζ, it can be determined that the vehicle is not flying when the engine speed NE is smaller than the engine speed ζ.

If YES is determined in step 200, the EEC 30 proceeds to step 201, and determines whether or not the PFC switch 38 is ON.
When it is determined that the target deck pressure PDa is equal to TPDP, the EEC 30 proceeds to step 202, and ends the routine.

On the other hand, if NO is determined in step 200 and if NO is determined in step 201, the EEC 30 proceeds to step 203, sets the target deck pressure PDa to TPDF, and ends this routine. I do.

It should be noted that TPDP needs to be set to a value higher than the atmospheric pressure expected at any airport on the earth. In the above-described example, in order to prevent the malfunction of the switch 38, it is determined in step 200 whether or not the aircraft is parked based on the magnitude of the engine speed NE to prevent the malfunction of the switch 38. Instead, it is checked whether or not the atmospheric pressure is equal to or higher than a predetermined value, and if YES is determined, it is determined that the aircraft is parked, and step 20 is performed.
It is also possible to prevent malfunction of the switch 38 by proceeding to 1. Further, it is also possible to check both the magnitude of the engine speed NE and the magnitude of the atmospheric pressure and proceed to step 201 only when both are determined to be YES.

Next, referring to the flowchart of FIG.
A procedure of a failure diagnosis method for a boost pressure control system by a preflight check according to the second embodiment will be described.
In this embodiment, TPDP is set to a pressure value smaller than TPDF (for example, TPDP = 1.200 kPa, TPDF = 1.466 kPa).

First, the operator starts the internal combustion engine 1 and operates the power lever 12 to slowly increase the engine speed NE (step 300). Next, in step 301, the operator looks at a deck pressure indicator (not shown) mounted on the aircraft, and determines that the deck pressure PD is TPDF.
Is determined.

When the supercharging pressure control system is functioning normally, the engine speed NE becomes equal to the intercept speed NE.
i (for example, 3450 rpm), the TPDF should be reached, and then the operator proceeds to step 301 with YES
It proceeds to step 302. If the deck pressure PD does not reach TPDF even if the engine speed NE is increased to a predetermined speed higher than the intercept speed NEi, that is, if NO is determined in step 301, the supercharging pressure control is performed at that time. Since it can be determined that there is an abnormality in the system, the operator proceeds to step 306, determines that there is an abnormality, and ends this routine.

Then, in step 302, when the deck pressure PD reaches the TPDF, the operator stops the operation of the power lever 12 and holds it at the stop position. next,
The operator turns on the PFC switch 38 to reduce the target deck pressure PDa to TPDP (step 303).

Then, the operator looks at the deck pressure indicator and determines whether or not the deck pressure PD converges on TPDP (step 304). If the supercharging pressure control system is functioning normally, the deck pressure PD should converge to TPDP, in which case the operator determines YES in step 304 and proceeds to step 305 to determine normal. To end this routine.

On the other hand, if the deck pressure PD does not converge on the TPDP even after a predetermined time has elapsed since the PFC switch 38 was turned on in step 303, the operator determines NO in step 304 and proceeds to step 306. Then, the routine is determined to be abnormal, and this routine ends.

FIG. 7 is a diagram showing the relationship between the engine speed NE and the deck pressure PD when the supercharging pressure control system is functioning normally. FIG. 8 shows that the supercharging pressure control system operates normally. If it is functioning, perform a preflight check and
6 shows a temporal transition of the engine speed NE and the deck pressure PD when the C switch 38 is turned ON / OFF.

When the supercharging pressure control system is determined to be abnormal in step 306, the cause of the abnormality is as follows.
The same reason as in the first embodiment described above can be considered, but in addition, a malfunction of the PFC switch 38 can be considered.

As described above, according to the method for diagnosing a failure of the supercharging pressure control system in the second embodiment, the engine speed NE is set to be relatively low in the vicinity of the intercept speed NEi. This is excellent in terms of protection of the internal combustion engine 1 and safety. In addition, since the two-point target deck pressure (TPDF and TPDP) is set to determine whether or not the deck pressure PD is controlled to each target deck pressure, the diagnostic accuracy is improved, and the probability of erroneous diagnosis is reduced. Extremely low.

In the above-described second embodiment, the timing for turning on the PFC switch 38 (hereinafter referred to as ON timing) is performed after the deck pressure PD reaches the PTDF. Is not limited to this. ON timing is the deck pressure PD
May be before reaching PTDF if the pressure becomes larger than TPDP by a predetermined pressure. If the ON timing is set before the deck pressure PD reaches the PTDF, the preflight check is performed in a state where the engine speed NE is lower than the intercept speed NEi. It is more preferable from the viewpoint of safety and the like.

In the above-described second embodiment, P
Although TDP is set smaller than PTDF, PTD
It is also possible to set P to be larger than PTDF.
However, from the viewpoints of protection of the internal combustion engine 1 and safety, it is preferable that PTDP is set smaller than PTDF.

In the second embodiment, the target deck pressure PDa is first set to TPDF, and the operation is started.
Next, the target deck pressure PDa is set to TPDP for operation. However, the setting order of the target deck pressure PDa is reversed, and the target deck pressure PDa is set to TPDP first, and then the setting is switched to TPDF. You may drive.

In the above-described second embodiment, the target deck pressure setting process shown in FIG. 5 is automatically performed by the EEC 30, and the preflight check operation shown in FIG. Manual operation, the operator looks at the deck pressure indicator, and determines whether it is normal or abnormal based on the indicated value. However, while automating a series of operations, the EEC 30 electrically calculates the PD sensor. It is also possible to electronically make the determinations of steps 301 and 304 by processing, display a normal / abnormal display in the cockpit, or sound an abnormal alarm. In this way, the operator only needs to perform an operation of turning on the switch for preflight check.

[0070]

According to the method of diagnosing a failure of the supercharging pressure control system of the present invention, the supercharging pressure control system is diagnosed at a relatively low rotational speed near the intercept rotational speed of the internal combustion engine. Therefore, the load on the internal combustion engine can be reduced, noise can be reduced, and safety can be improved.

Further, according to the failure diagnosis method of the present invention, it is possible to judge that the waste gate valve is stuck, which may be overlooked by the conventional failure diagnosis method, without fail, so that the accuracy of diagnosis is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an aircraft internal combustion engine which is an example of a supercharged internal combustion engine.

FIG. 2 is a diagram showing a schematic configuration of a control device of the supercharged internal combustion engine.

FIG. 3 is a flowchart showing a diagnosis processing procedure in the first embodiment of the failure diagnosis method for the supercharging pressure control system for the internal combustion engine according to the present invention.

FIG. 4 is a diagram illustrating an example of changes in deck pressure, engine speed, and WGV opening when the failure diagnosis method according to the first embodiment is performed.

FIG. 5 is a flowchart showing a target deck pressure setting processing procedure in a second embodiment of the failure diagnosis method for the supercharging pressure control system for an internal combustion engine according to the present invention.

FIG. 6 is a flowchart illustrating a diagnostic processing procedure according to the second embodiment.

FIG. 7 is a diagram showing the relationship between deck pressure and engine speed in the second embodiment.

FIG. 8 is a diagram illustrating an example of a change in deck pressure and engine speed when the failure diagnosis method according to the second embodiment is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal-combustion engine with a supercharger 10 Exhaust turbocharger (supercharger) 12 Power lever 26 WGV (a waste gate valve) 32 Speed sensor 34 Deck pressure sensor 38 Preflight check switch (switching means)

Claims (4)

[Claims] 1. A failure diagnosis method for a supercharging pressure control system for controlling a supercharging pressure to be equal to a target supercharging pressure by adjusting an opening of a waste gate valve of a supercharged internal combustion engine. The engine speed is maintained at a predetermined speed in a rotation region where the supercharging pressure becomes the target supercharging pressure, and then the engine speed is changed by a predetermined amount, and the supercharging pressure after the engine speed changes and the target supercharging are changed. When the difference from the pressure is within a predetermined allowable range, it is determined that the supercharging pressure control system is normal, and when the difference is out of the allowable range, it is determined that the supercharger is abnormal. A failure diagnosis method for a boost pressure control system in an internal combustion engine. 2. A failure diagnosis method for a supercharging pressure control system for controlling a supercharging pressure to be equal to a target supercharging pressure by adjusting an opening of a waste gate valve of an internal combustion engine with a supercharger. A first target boost pressure in a normal engine operating state and a second diagnostic boost value different from the first target boost pressure.
In addition to setting the target supercharging pressure, the switching means can select either the first target supercharging pressure or the second target supercharging pressure, and
The switching means is switched to select the respective target supercharging pressures to perform the operation, and it is determined whether or not the actual supercharging pressure converges to the target value with respect to the selected target supercharging pressure. A failure diagnosis method for a supercharging pressure control system in a supercharged internal combustion engine, characterized in that an abnormality is determined when the pressure does not converge to the supply pressure. 3. The method according to claim 2, wherein the second target boost pressure is set to be smaller than the first target boost pressure.
3. A failure diagnosis method for a supercharging pressure control system in an internal combustion engine with a supercharger according to claim 1. 4. The supercharging pressure control in a supercharged internal combustion engine according to claim 2, wherein the engine speed is kept constant before the target supercharging pressure is switched by the switching means. System failure diagnosis method.