JPH09273445A - Torque abnormality determining device for engine provided with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase torque abnormality determining precision so as to prevent error determination when an engine brake is operated. SOLUTION: A torque abnormality determining device is provided with a turbocharger 43, a rotational speed sensor 56, an accelerator opening sensor 58, an intake pressure sensor 59, and an electronic controller (ECU) 62. The turbocharger 43 uses exhaust gas flowing in an exhaust passage 44 so as to rotate a compressor 47, so that the air flowing in the intake passage 46 is supercharged. A rotational speed sensor 57 detects an engine rotational speed, the accelerator opening sensor 58 detects an operation quantity (accelerator opening) of an accelerator pedal 51, and the intake pressure sensor 59 detects a pressure (intake pressure) inside the intake passage 46 on the downstream side beyond the compressor 47. The ECU 62 determines torque abnormality if the accelerator opening is a first predetermined value or less, the engine rotational speed is a second predetermined value or more, and the intake pressure is a third predetermined value complying with the atmospheric pressure or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque abnormality determining device for determining whether or not the torque of an engine with a supercharger is an abnormality indicating that the torque is larger than a torque required by a driver. is there.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with, for example, a diesel engine, an unintended torque is generated while the accelerator pedal is not depressed and the engine rotational speed is generated while traveling on a level ground or an uphill. If the height becomes high, the driver feels uncomfortable. Therefore, in such a case, that is, when the accelerator pedal depression amount (accelerator opening degree) is equal to or lower than the first predetermined value and the engine rotation speed is equal to or higher than the second predetermined value, the torque of the diesel engine is increased by the driver. It is determined that the torque is abnormal, which indicates that the torque is larger than the torque required by. The causes of such abnormalities are, for example, excessive fuel being supplied to the diesel engine due to a malfunction of the fuel injection pump, engine oil entering the combustion chamber due to wear of the piston ring, wear of the shaft part of the intake / exhaust valve, etc. It is possible that it will flow in and be burned. And
At the time of this abnormality determination, the sub-valve in the bypass path that bypasses the main valve is fully closed or half-opened. Then, the intake air amount is limited, the generation of unintended torque is suppressed, and the abnormal increase in the engine rotation speed is avoided.

[0003]

However, both of the above conditions are satisfied even when the vehicle is running on a downhill or the like and the engine brake is in effect. Here, the state in which the engine brake is applied means that a force larger than the output of the engine is input from the drive system even though the accelerator pedal is not depressed while the engine and the drive system are connected. The pumping loss and the friction loss of the engine serve as a braking force, and the vehicle is decelerated as if it has been braked. In this state, the accelerator opening is small and the engine speed is high. Therefore, even if each part of the engine and the fuel injection pump are operating normally, it is erroneously determined that the torque is abnormal and the sub-valve is closed unnecessarily.

When the intake air amount is unnecessarily limited by closing the sub-valve, the pressure in the combustion chamber during the intake stroke becomes lower than when the intake air amount is not limited. The amount of engine oil adhering to the cylinder bore or the like flowing into the combustion chamber increases. Further, when the intake air amount is unnecessarily limited, the temperature of the air when the piston rises to the compression top dead center becomes less likely to rise than when it is not limited. As a result, part of the fuel and part of the engine oil that has flowed in during the intake stroke may be discharged as white smoke without being burned.

The present invention has been made in view of the above-mentioned circumstances, and a first object thereof is to improve the accuracy of torque abnormality determination and prevent erroneous determination when the engine brake is operating. , The second purpose is in addition to the first purpose,
By effectively using the determination result, it is possible to prevent unnecessary restriction of the intake air amount and solve the problem that fuel and engine oil are discharged without being burned.

[0006]

In order to achieve the above object, the first aspect of the present invention uses the exhaust gas flowing through the exhaust passage M2 of the engine M1 as shown in FIG. By operating the compressor M4 in the intake passage M3 of the engine M1, the supercharger M5 that supercharges the air flowing in the intake passage M3 and the operation amount of the accelerator operating member M6 operated by the driver are detected. Accelerator operation amount detection means M7, rotation speed detection means M8 for detecting the rotation speed of the engine M1, pressure detection means M9 for detecting the pressure in the intake passage M3 downstream of the compressor M4, and accelerator operation The accelerator operation amount by the amount detection means M7 is less than or equal to a first predetermined value, the rotation speed by the rotation speed detection means M8 is greater than or equal to a second predetermined value, and the pressure is When the pressure from the output means M9 is equal to or higher than a third predetermined value corresponding to the atmospheric pressure, the torque abnormality determination means determines that the torque of the engine M1 is larger than the torque required by the driver. And M10.

Here, in the engine M1 in which the supercharger M5 is incorporated and each part is operating normally, supply is performed under the condition that the operation amount of the accelerator operation member M6 is equal to or less than a first predetermined value (for example, zero). There is little fuel. The supercharging by the supercharger M5 is slight, and the pressure in the intake passage M3 downstream of the compressor M4 tends to be lower than the third predetermined value corresponding to the atmospheric pressure. More specifically, the pressure becomes maximum (almost atmospheric pressure) when the engine M1 is in an idle state (when the engine load is small), and tends to decrease as the rotation speed of the engine M1 increases.
This is because the intake air is forcibly sucked in the intake stroke under the condition that the supercharging is not performed and the intake air amount is limited according to the operation of the accelerator operation member M6.

On the other hand, an excessive amount of fuel is consumed by the engine M.
When the engine oil is supplied to the engine 1 or the engine oil enters the combustion chamber, the energy generated by the combustion increases. The pressure in the exhaust passage M2 becomes high, and the supercharger M
Due to the intake air supercharging accompanying the operation of 5, the compressor M
The pressure in the intake passage M3 downstream of 4 increases and becomes equal to or higher than the third predetermined value.

Therefore, if the torque abnormality determination is not performed when the pressure in the intake passage M3 is lower than the third predetermined value, it is possible to avoid an erroneous determination. From such a viewpoint, in the first invention, the accelerator operation amount detection means M7 detects the operation amount of the accelerator operation member M6, and the rotation speed detection means M8 detects the rotation speed of the engine M1.
The pressure detection means M9 detects the pressure in the intake passage M3 downstream of the compressor M4. Torque abnormality determination means M
In addition to the condition that the accelerator operation amount is less than or equal to the first predetermined value and the rotation speed of the engine M1 is greater than or equal to the second predetermined value, 10 is when the pressure in the intake passage M3 is greater than or equal to the third predetermined value. It is determined that the torque is abnormal. Therefore, even if the engine brake operates and the rotation speed of the engine M1 increases, the pressure in the intake passage M3 does not exceed the third predetermined value unless the increase in rotation is due to excessive fuel supply. Therefore, the torque is not erroneously determined as abnormal.

In a second aspect of the present invention, as shown in FIG. 1, in addition to the structure of the first aspect, the intake passage M
Intake throttle valve M1 provided in No. 3 for adjusting the intake air amount
1 and valve driving means M1 for driving the intake throttle valve M11
2, and an intake throttle control means M13 for operating the valve drive means M12 to reduce the intake air amount by the intake throttle valve M11 when the torque abnormality determination means M10 determines that the torque is abnormal. .

In the second aspect of the invention, when the torque abnormality determining means M10 determines that the torque is abnormal, the intake throttle control means M13 operates the valve driving means M12 to reduce the intake air amount by the intake throttle valve M11. Let In this way, the limit of the intake air amount at the time of torque abnormality determination is
The intake air amount is unnecessarily limited even if the torque abnormality is erroneously determined. Then, the pressure in the combustion chamber during the intake stroke becomes lower than when the pressure is not limited. The amount of engine oil adhering to the cylinder bore or the like flowing into the combustion chamber increases. Further, when the intake air amount is unnecessarily limited, the temperature of the air when the piston rises to the compression top dead center becomes less likely to rise than when it is not limited.
As a result, part of the fuel and part of the engine oil that has flowed in during the intake stroke may be discharged as white smoke without being burned.

However, as described above, since the comparison between the pressure in the intake passage M3 downstream of the compressor M4 and the third predetermined value is added to the torque abnormality determination condition,
Even if the rotation speed of the engine M1 is a proper value, it is less likely that the torque abnormality is erroneously determined.
With this, there is no unnecessary restriction of intake air volume,
The inflow of engine oil into the combustion chamber during the intake stroke and the temperature decrease of the intake air during the compression stroke are suppressed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the first and second inventions are embodied will be described below with reference to FIGS.

As shown in FIG. 2, a vehicle is equipped with a diesel engine 11 having a plurality of cylinders and a fuel injection pump 12. The fuel injection pump 12 is for supplying fuel to the injection nozzle 13 provided for each cylinder of the diesel engine 11. A drive shaft 14 is rotatably supported by the fuel injection pump 12, and the drive pulley 1 is attached to one end (the left end in the figure) of the shaft 14.
5 is attached. A belt or the like is mounted on the drive pulley 15 and the crankshaft 16 of the diesel engine 11, and the rotation of the crankshaft 16 is transmitted to the drive shaft 14 by the drive pulley 15, the belt, and the like.

In the fuel injection pump 12, a fuel feed pump (developed by 90 degrees in the figure) 17 which is a vane type pump is provided on the drive shaft 14. A disk-shaped pulsar 18 is attached to the other end (right end in the figure) of the drive shaft 14. The same number of teeth as the number of cylinders of the diesel engine 11 are formed on the outer peripheral surface of the pulsar 18 at equal angular intervals, and a predetermined number of protrusions are formed at equal angular intervals between adjacent teeth. The other end of the drive shaft 14 is a coupling (not shown)
It is connected to the cam plate 19 via.

A roller ring 20 is provided between the pulsar 18 and the cam plate 19, and a plurality of cam rollers 21 facing the cam face 19a of the cam plate 19 are attached along the circumference of the roller ring 20. . The cam faces 19a are provided in the same number as the number of cylinders of the diesel engine 11. The cam plate 19 is biased by a spring 22 and is always engaged with the cam roller 21.

A plunger 23 for fuel pressurization is attached to the cam plate 19, and both members 19 and 23 interlock with the rotation of the drive shaft 14 and rotate integrally. That is, the rotational force of the drive shaft 14 is transmitted to the cam plate 19 via the coupling.
By this transmission, the cam plate 19 is engaged with the cam roller 21 while rotating, and reciprocates in the left-right direction in the drawing the same number of times as the number of cylinders. With this reciprocating motion, the plunger 23
Reciprocates in the same direction while rotating. That is, the plunger 23 moves forward (lifts) while the cam face 19a rides on the cam roller 21, and vice versa.
In the process of a riding on the cam roller 21, the plunger 23
Comes back.

The plunger 23 is fitted in the cylinder 25 of the pump housing 24. A high pressure chamber 26 is formed between the tip end surface (the right end surface in the drawing) of the plunger 23 and the inner bottom surface of the cylinder 25. A suction groove 27 and a distribution port 28 are formed on the outer periphery of the tip of the plunger 23 in the same number as the number of cylinders of the diesel engine 11. A distribution passage 29 and a suction port 30 are formed in the pump housing 24 so as to correspond to the suction groove 27 and the distribution port 28.

When the drive shaft 14 rotates and the fuel feed pump 17 operates, the fuel in the fuel tank (not shown) is supplied to the fuel chamber 32 through the fuel supply port 31. Further, during the suction stroke in which the plunger 23 moves back and the high pressure chamber 26 is depressurized, the suction groove 27
By communicating one of them with the suction port 30, the fuel in the fuel chamber 32 is introduced into the high pressure chamber 26. On the other hand, during the compression stroke in which the plunger 23 moves forward and the high-pressure chamber 26 is pressurized, fuel is pressure-fed from the distribution passage 29 to each injection nozzle 13.

In the pump housing 24, a spill passage 33 for fuel overflow (spill) is formed which connects the high pressure chamber 26 and the fuel chamber 32. An electromagnetic spill valve 34 is provided in the middle of the spill passage 33. Electromagnetic spill valve 3
Reference numeral 4 is a normally open valve having a coil 35, and the coil 3
When 5 is not energized (OFF), the valve element 36 is opened and the fuel in the high pressure chamber 26 is spilled into the fuel chamber 32. Also,
When the coil 35 is energized (turned on), the valve body 36
Is closed to stop the fuel spill from the high pressure chamber 26 to the fuel chamber 32.

Therefore, by changing the energization time of the electromagnetic spill valve 34, the spill valve 34 is controlled to be closed / opened, and the spill of fuel from the high pressure chamber 26 to the fuel chamber 32 is adjusted. Then, by opening the electromagnetic spill valve 34 during the compression stroke of the plunger 23, the fuel in the high pressure chamber 26 is depressurized and the fuel injection from the injection nozzle 13 is stopped. That is, even if the plunger 23 moves forward, the fuel pressure in the high-pressure chamber 26 does not rise and the fuel is not injected from the injection nozzle 13 while the electromagnetic spill valve 34 is open. During the forward movement of the plunger 23, the electromagnetic spill valve 3
By controlling the valve closing / opening timing of No. 4, the fuel injection end timing of the fuel from the injection nozzle 13 is changed and the fuel injection amount is adjusted.

Below the pump housing 24 is provided a timer device (developed 90 degrees in the figure) 37 for changing the fuel injection timing. Timer device 37
By changing the position of the roller ring 20 with respect to the rotation direction of the drive shaft 14,
9a is engaged with the cam roller 21, that is, the reciprocating drive timing of the cam plate 19 and the plunger 23 is changed.

Next, the diesel engine 11 will be described. In the engine 11, the cylinder bore 38, the piston 39 having the piston ring 39a attached thereto, and the cylinder head 40 allow the main combustion chamber 41 corresponding to each cylinder.
Are formed respectively. Further, a sub combustion chamber 42 communicating with each main combustion chamber 41 is provided corresponding to each cylinder. The injection nozzle 13 is attached to the cylinder head 40 so that the tip of the cylinder head 40 faces each auxiliary combustion chamber 42.

A turbocharger 43 as a supercharger is mounted on the diesel engine 11. The turbocharger 43 includes a turbine 45 arranged in the middle of the exhaust passage 44, a compressor 47 arranged in the middle of the intake passage 46, the turbine 45 and the compressor 47.
And a shaft 48 for connecting In the turbocharger 43, the turbine 4 is driven by the energy of the exhaust gas.
5, the intake air is compressed by operating the coaxial compressor 47, and the diesel engine 11
Supply high-density intake air above atmospheric pressure. The exhaust passage 44 is provided with a waste gate valve 49 for adjusting the supercharging pressure by the turbocharger 43.

A main valve 50 is provided in the middle of the intake passage 46.
Are rotatably supported. The valve 50 and an accelerator pedal 51 as an accelerator operating member provided in the driver's seat are connected by a cable 61. The main valve 50 is rotated in association with the depression operation of the accelerator pedal 51 by the driver. Then, the amount of air flowing through the intake passage 46 is adjusted according to the rotation angle of the main valve 50.

A bypass passage 52, which bypasses the main valve 50, is provided in the intake passage 46, and a sub valve 53 as an intake throttle valve is rotatably supported in the middle of the bypass passage 52.
The sub-valve 53 is a fully closed position that intersects the flow of intake air and closes the bypass passage 52, a fully open position that is parallel to the flow of intake air and opens the bypass passage 52, and a half open position that is an intermediate position between the two positions. And are taken selectively. Sub valve 53
The restriction amount of intake air due to increases in the order of the fully open position, the half open position, and the fully closed position.

In order to rotate the sub valve 53 between the above-mentioned three positions, valve driving means as shown in FIG. 4 is provided. Explaining the same means, an actuator 56 is connected to the sub valve 53. The actuator 56 includes a pair of diaphragm chambers 56a and 56b and a shaft 56c.
By introducing atmospheric pressure or negative pressure into a and 56b, the shaft 56c is reciprocated in the left-right direction in FIG. 4, and the sub-valve 53 is rotated. The diaphragm chambers 56 a and 56 b are connected to a vacuum pump 82 via a negative pressure passage 81. In order to switch the pressure introduced into the diaphragm chambers 56a, 56b, a vacuum switching valve (hereinafter referred to as "V
SV ") 54, 55 are used. VSV5
4, 55 are diaphragm chambers 56a,
Negative pressure by the vacuum pump 82 is introduced into 56b, and atmospheric pressure is introduced when not energized.

For example, when the diesel engine 11 is stopped, both VSVs 54 and 55 are energized in order to cut off intake air and reduce engine vibration. Then, negative pressure is introduced into both diaphragm chambers 56a and 56b, and the sub-valve 53 rotates to the fully closed position. Further, during idle operation after warm-up, one VSV 54 is energized and the other VSV 55 is de-energized in order to reduce engine vibration and noise. Then, a negative pressure is introduced into the diaphragm chamber 56a and an atmospheric pressure is introduced into the diaphragm chamber 56b,
The sub valve 53 rotates to the half open position. In addition, the power supply to the VSVs 54 and 55 is stopped at the time of starting or idling in the cold state. Then, both diaphragm chambers 56a, 5
Atmospheric pressure is introduced into 6b, and the sub-valve 53 rotates to the fully open position.

In the diesel engine 11 having the above structure,
When the engine 11 is operating normally,
FIG. 5 shows the relationship between the engine speed NE and the intake pressure VPIM.
You can see the relationship as shown in. In the figure, the solid line shows the characteristic line when the accelerator pedal 51 is fully depressed, and the two-dot chain line shows the characteristic line when the accelerator pedal 51 is not depressed. The normal operation of the diesel engine 11 here means that an appropriate amount of fuel is being supplied from the fuel injection pump 12 to the diesel engine 11, causing wear of the piston ring 39a, wear of the shaft portion of the intake / exhaust valve 80, and the like. This is a state in which the amount of engine oil that flows into the main combustion chamber 41 is small.

As is apparent from these characteristic lines, when the depression amount of the accelerator pedal 51 is maximum, the intake pressure VPIM increases almost in proportion to the increase of the engine speed NE. On the other hand, when the depression amount of the accelerator pedal 51 is zero, the amount of fuel injected from the injection nozzle 13 is small. Supercharging by the turbocharger 43 is small, and the pressure in the intake passage 46 (intake pressure VPIM) downstream of the compressor 47 tends to be lower than atmospheric pressure. More specifically, the intake pressure VPIM has a maximum (almost atmospheric pressure) when the diesel engine 11 is in an idle state (when the engine load is small), and tends to decrease as the engine speed NE increases. this is,
In a situation where the intake valve 46 is closed by the main valve 50 in response to a depression operation of the accelerator pedal 51 without supercharging and the intake air amount is limited, the intake air is reduced by lowering the piston 39 in the intake stroke. This is because it is forcibly sucked. Such a characteristic can be similarly observed even when engine braking is applied or the vehicle is traveling at a high altitude.

The following various sensors are provided to detect the operating state of the diesel engine 11.
As shown in FIG. 2, above the roller ring 20 in the fuel injection pump 12, a rotation speed sensor 57 as a rotation speed detecting means is attached so as to face the outer peripheral surface of the pulsar 18. The rotation speed sensor 57 is composed of an electromagnetic pickup coil, detects passage of the protrusions formed on the outer peripheral surface of the pulsar 18 when they cross, and outputs a timing signal (engine rotation pulse). That is, the rotation speed sensor 57 outputs a pulse signal for each predetermined crank angle of the diesel engine 11. This rotation speed sensor 57
Is integrated with the roller ring 20, the timer device 37
Regardless of the control operation of, the reference signal is output to the plunger lift at a constant timing.

The intake passage 46 is provided with an accelerator opening sensor 58 as an accelerator operation amount detecting means.
The sensor 58 determines the operation amount (depression amount) of the accelerator pedal 51 by the driver from the rotation angle of the main valve 50.
The accelerator opening degree ACCP is detected. The accelerator opening ACCP corresponds to the load of the diesel engine 11. Compressor 4 in intake passage 46
An intake pressure sensor 59 as a pressure detecting means for detecting the intake pressure VPIM after being supercharged by the turbocharger 43 is provided at a position downstream of 7. Further, a vehicle speed sensor 60 for detecting the traveling speed (vehicle speed) SPD of the vehicle is provided.

Based on the detection results of the sensors 57-60,
An electronic control unit (hereinafter referred to as “ECU”) 62 is used to drive and control the electromagnetic spill valve 34 and the VSVs 54 and 55 described above. As shown in the block diagram of FIG. 3, the ECU 62 includes a central processing unit (CPU) 63, a read-only memory (ROM) 64 in which a predetermined control program, a map and the like are stored in advance, and a random access for temporarily storing a calculation result of the CPU 63. Memory (RAM) 65, backup RAM 66 for storing prestored data
It has. These parts 63 to 66 and the input port 67
And the output port 68 are connected by a bus 69.

The accelerator opening sensor 58 and the intake pressure sensor 59 described above are connected to the input port 67 via buffers 71 and 72, a multiplexer 73 and an A / D converter 74, respectively. The rotation speed sensor 57 and the vehicle speed sensor 60 are connected to the input port 67 via the waveform shaping circuit 75.
It is connected to the. The CPU 63 reads the detection signals of the sensors 57-60 via the input port 67.

Further, the electromagnetic spill valve 34 and the VSV 54,
55 is connected to the output port 68 via drive circuits 76, 77 and 78, respectively. The CPU 63 suitably controls the electromagnetic spill valve 34 and the VSVs 54, 55 based on the input value read via the input port 67.

The flowchart shown in FIG. 6 shows a routine for calculating the atmospheric pressure VGPIM, out of various processes performed by the CPU 63. This routine is executed at a predetermined timing.

First, in step 101, the CPU 63 calculates an engine rotation speed NE, which is the rotation speed of the crankshaft 16 per unit time, based on the engine rotation pulse output from the rotation speed sensor 57. It is determined whether the engine rotation speed NE matches the engine rotation speed when the diesel engine 11 is idle. Further, in step 102, it is determined whether or not the vehicle speed SPD by the vehicle speed sensor 60 is 0 Km / h. In step 103, it is determined whether or not the accelerator opening ACCP by the accelerator opening sensor 58 is 0%.

If any one of the determination conditions in steps 101 to 103 is not satisfied, the turbocharger 43 is supercharging the intake air, and the intake pressure VPIM at that time is different from the atmospheric pressure. Judgment is made and this routine is finished. On the other hand, if all the determination conditions of steps 101 to 103 are satisfied, that is, the diesel engine 11 is in the idle state, the vehicle is stopped, and the accelerator pedal 51 is not depressed, the turbocharger It is determined that supercharging by 43 is not performed, and the process proceeds to step 104. Step 10
4 shows the intake pressure VP measured by the intake pressure sensor 59 at that time.
Set IM as atmospheric pressure VGPIM. Then, this routine ends.

As described above, in the atmospheric pressure calculation routine, the intake pressure VP when the diesel engine 11 is in the non-supercharged state
IM is set as atmospheric pressure VGPIM. Next, the flowchart shown in FIG. 7 shows a routine for determining a torque abnormality and controlling the VSVs 54, 55 based on the determination result. This routine is executed at a predetermined timing.

In step 201, the CPU 63 determines whether or not the accelerator opening ACCP measured by the accelerator opening sensor 58 is less than or equal to a first predetermined value β. The first predetermined value β is a value when the accelerator pedal 51 is not depressed or is in a state close thereto, and is set to "4%" as an example thereof. In step 202, it is determined whether the engine speed NE is equal to or higher than a second predetermined value γ. The second predetermined value γ indicates that the diesel engine 11 and the fuel injection pump 12 are operating normally and the accelerator opening ACCP is equal to the first predetermined value (4
%) Is the maximum value that the engine speed NE can take when it is held at, or a value close to it, and here it is "1".
It is set to "600 rpm". In step 203, the intake pressure VP at that time by the intake pressure sensor 59
It is determined whether IM is greater than or equal to a third predetermined value δ corresponding to atmospheric pressure. Here, as the third predetermined value δ, a value obtained by adding the value α to the atmospheric pressure VGPIM calculated in the atmospheric pressure calculation routine is used.

If any one of the judgment conditions of steps 201 to 203 is not satisfied, the engine speed NE is a proper value, in other words, the torque is not abnormal.
Then, this routine is finished.

On the other hand, if all the judgment conditions of steps 201 to 203 are satisfied, the engine speed N
It is determined that a so-called torque abnormality is occurring, which indicates that E is abnormally high and the torque of the diesel engine 11 is larger than the torque required by the driver, and the process proceeds to step 204. In step 204, the sub-valve 53 is closed more than when the torque abnormality has not occurred. For example, if the sub-valve 53 was held in the fully open position until then, one VSV 54
Is energized to stop the energization to the other VSV 55. Then, negative pressure is introduced into the diaphragm chamber 56a, atmospheric pressure is introduced into the diaphragm chamber 56b, and the sub-valve 53 is rotated to the half-open position. Also, if the sub-valve 53 was held in the half-open position until then, both VSVs 54, 5
5 is energized. Then, both diaphragm chambers 56a, 56
Negative pressure is introduced to b, and the sub valve 53 rotates to the fully closed position. After executing the processing of step 204, this routine is ended.

In the intake throttle control routine described above,
The processing of steps 201, 202 and 203 by the CPU 63 corresponds to the torque abnormality determining means, and the processing of step 204 corresponds to the intake throttle control means.

In the intake throttle control routine, the intake pressure VPIM is added to the accelerator opening ACCP and the engine speed NE as the conditions for determining the torque abnormality for the following reason. As described above, if the diesel engine 11 and the fuel injection pump 12 are normally operating and excess fuel and engine oil are not burned,
The first predetermined value β (4
%) Or less, the fuel injection amount is small, and supercharging by the turbocharger 43 is small. In the state where the intake passage 46 is closed by the main valve 50, the intake air is forcibly sucked by the negative pressure accompanying the lowering of the piston 39, so that the intake pressure VPIM is the third predetermined value δ corresponding to the atmospheric pressure. It becomes lower than (VGPIM + α). Such a phenomenon also occurs when the engine brake is in effect while the vehicle equipped with the manual transmission is traveling downhill or the like.

On the other hand, for example, an excessive amount of fuel is supplied to the diesel engine 11 due to a malfunction of the fuel injection pump 12, engine piston 39a is worn, the intake / exhaust valve 80 is worn on the shaft portion of the engine oil, etc. When it flows into 41, 42 and is burned,
The energy generated by the combustion increases. The pressure in the exhaust passage 44 increases and the turbocharger 43
Due to the intake air supercharging accompanying the operation of
Pressure in the intake passage 46 (intake pressure VPI
M) increases, and the third predetermined value δ (VGPIM + α)
That is all.

Therefore, if the torque abnormality determination is not performed when the intake pressure VPIM is lower than the third predetermined value δ, it is possible to avoid an erroneous determination. From this point of view, in the present embodiment, the accelerator opening ACCP
Is equal to or lower than a first predetermined value β (4%) and the engine speed NE is equal to or higher than a second predetermined value γ (1600 rpm), and the intake pressure VPIM is equal to a third predetermined value corresponding to the atmospheric pressure. When the value is δ (VGPIM + α) or more, it is determined that the torque is abnormal. Therefore, even if the engine braking is applied and the engine speed NE becomes high, the intake pressure VPIM does not become the third predetermined value δ or more unless the increase in rotation is due to excessive fuel supply. It is not erroneously determined as abnormal torque. As described above, according to the present embodiment, it is possible to improve the accuracy of determination of the torque abnormality and prevent the erroneous determination especially when the engine brake is operating.

Further, in the present embodiment, when it is judged that the torque is abnormal, the energization of the VSVs 54 and 55 is controlled to operate the actuator 56, and the bypass valve 52 is throttled by the sub valve 53 so as to reduce the intake air amount. I have to. Therefore, it is possible to suppress an abnormal increase in the engine rotation speed NE.

By the way, in the case of limiting the intake air amount when the torque abnormality is determined as described above, the intake air amount is unnecessarily limited even when the torque abnormality is erroneously determined. Then, the pressure in the combustion chambers 41, 42 during the intake stroke becomes lower than when the pressure is not limited. A combustion chamber 41 for engine oil adhering to the cylinder bore 38,
The amount of inflow into 42 increases. Further, when the intake air amount is unnecessarily limited, the combustion chamber 4 is compared to when it is not limited.
The amount of air flowing into 1, 42 is reduced. The temperature of the air when the piston 39 rises to the compression top dead center becomes difficult to rise. As a result, part of the fuel and part of the engine oil that has flowed in during the intake stroke may be discharged as white smoke without being burned.

However, as described above, the intake pressure VPIM and the third predetermined value δ (VGP
Since the comparison with (IM + α) is added, it is less likely that the engine speed NE is erroneously determined to be abnormal torque even though the engine speed NE is a proper value. As a result, unnecessary restriction of the intake air amount is eliminated, and the inflow of engine oil into the combustion chambers 41, 42 during the intake stroke and the temperature decrease of the intake air during the compression stroke can be suppressed. It is possible to reduce the amount of white smoke emitted without burning the fuel and engine oil.

The present embodiment has the following features in addition to the matters described above. (A) As the third predetermined value δ used for the torque abnormality determination condition, the value obtained by adding the value α to the atmospheric pressure VGPIM is used. Therefore, as compared with the case where the atmospheric pressure VGPIM is set to the third predetermined value δ without adding the value α, it is less likely that the torque abnormality is determined by the value α. That is, if the intake pressure VPIM is substantially equal to the atmospheric pressure VGPIM when the value α is not added, even if it is determined that the torque is abnormal,
When the value α is added, it may not be determined that the torque is abnormal. Then, as compared with the case where the value α is not added, the opening degree of the sub valve 53 is increased, the torque of the diesel engine 11 is increased, and the vehicle speed SPD is increased.

Therefore, depending on how to set this value α,
The vehicle speed SPD when it is determined that the torque is abnormal can be set to an arbitrary value. For example, when the value α is set to a large value, the vehicle speed SPD at which the vehicle can travel increases, and when the value α is set to a small value, the vehicle speed SPD decreases. Even when the torque abnormality occurs, the vehicle speed SPD is not set to zero or a value close thereto, but traveling at a certain vehicle speed SPD can be ensured and traveling to the destination is possible.

The present invention can be embodied in another embodiment shown below. (1) The present invention can be applied to a gasoline engine as well as the diesel engine 11.

(2) The present invention can be applied to any engine having a structure in which the intake passage is throttled regardless of the depression operation of the accelerator pedal 51, in addition to the engine having the sub-valve 53.

(3) In the above embodiment, a value obtained by adding the value α to the atmospheric pressure VGPIM is used as the third predetermined value δ, but this value α is omitted and the atmospheric pressure VGPIM itself is used as the third value. The predetermined value δ may be used.

(4) An atmospheric pressure sensor may be provided separately from the intake pressure sensor 59, and the detection result may be used as the atmospheric pressure VGPIM in the intake throttle control routine of FIG. Although the respective embodiments of the present invention have been described above, technical ideas other than the claims that can be understood from the respective embodiments will be described below together with their effects.

(A) In the torque abnormality determination device according to the first aspect, the engine is mounted on a vehicle, and the third predetermined value is the atmospheric pressure plus a predetermined value α. Torque abnormality determination device for supercharged engine. With such a configuration, by appropriately setting the magnitude of the value α, the condition for judging abnormal torque is slightly relaxed,
It is possible to drive the vehicle at a certain vehicle speed even when the torque is abnormal.

[0057]

According to the first aspect of the present invention, it is possible to improve the accuracy of determination of torque abnormality and prevent erroneous determination when the engine brake is operating.

According to the second invention, in addition to the effect of the first invention, when the engine is of a type in which the intake passage is throttled at the time of abnormality determination, the intake air amount can be effectively utilized by utilizing the determination result. It is possible to prevent unnecessary restriction of the above and solve the problem that fuel and engine oil are discharged without being burned.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram showing a basic conceptual configuration of first and second inventions.

FIG. 2 is a schematic configuration diagram of a fuel injection pump and a diesel engine.

FIG. 3 is a block diagram showing an internal configuration of an ECU.

FIG. 4 is a schematic configuration diagram showing a mechanism for driving a sub valve.

FIG. 5 is a characteristic diagram showing a correspondence relationship between engine rotation speed and intake pressure.

FIG. 6 is a flowchart showing an atmospheric pressure calculation routine.

FIG. 7 is a flowchart showing an intake throttle control routine.

[Explanation of symbols]

11 ... Diesel engine, 43 ... Turbocharger as supercharger, 44 ... Exhaust passage, 46 ... Intake passage, 47
... compressor, 51 ... accelerator pedal as accelerator operating member, 53 ... sub valve as intake throttle valve, 5
6 ... Actuator, 57 ... Rotation speed sensor as rotation speed detection means, 58 ... Accelerator opening sensor as accelerator operation amount detection means, 59 ... Intake pressure sensor as pressure detection means, ACCP ... As operation amount of accelerator operation member Accelerator opening, VPIM ... Intake pressure, VGPIM ...
Atmospheric pressure, NE ... engine speed, β ... first predetermined value,
γ ... second predetermined value, δ ... third predetermined value.

Claims (2)

[Claims] 1. A supercharger for operating a compressor in an intake passage of an engine by utilizing exhaust gas flowing through the exhaust passage of the engine, and a supercharger for supercharging air flowing in the intake passage, and a driver operated by the driver. Accelerator operation amount detecting means for detecting an operation amount of an accelerator operating member, rotation speed detecting means for detecting a rotation speed of the engine, and pressure detecting means for detecting a pressure in an intake passage downstream of the compressor. And the accelerator operation amount by the accelerator operation amount detecting means is less than or equal to a first predetermined value, the rotation speed by the rotation speed detecting means is more than a second predetermined value, and the pressure by the pressure detecting means is large. When the value is equal to or higher than the third predetermined value corresponding to the atmospheric pressure, it is determined that the torque of the engine is abnormal than the torque required by the driver. Torque failure determination device for an engine with a supercharger having a torque abnormality judgment means for. 2. An intake throttle valve provided in the intake passage for adjusting the intake air amount, valve drive means for driving the intake throttle valve, and when the torque abnormality determination means determines that the torque is abnormal, A torque abnormality determination device for an engine with a supercharger, further comprising an intake throttle control means for operating the valve drive means to reduce an intake air amount by an intake throttle valve.