JP3235892B2 - Mechanical turbocharger abnormality detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine having a mechanical supercharger in an intake system, and more particularly to an apparatus capable of detecting an abnormal state in which the supercharger cannot rotate due to icing. .

[0002]

2. Description of the Related Art Conventionally, in an engine having a mechanical supercharger in an intake system, EGR means of a type in which exhaust gas is recirculated upstream of the mechanical supercharger or blow-by gas from a crankcase of the engine is supplied. Some include a means for refluxing upstream of the feeder.

[0003] In the case of such an engine in which the additional gas or the like of the intake air is supplied to the upstream side, when the engine is stopped from the supercharging state and left overnight during extremely cold weather, the moisture inside the mechanical supercharger freezes at night. There is a case where so-called icing occurs and the engine cannot be rotated the next morning when the engine is started. This is because the EGR gas or the like contains a large amount of moisture, and the moisture of the EGR gas is supplied at the same time as the intake air, remains in the mechanical supercharger, and freezes.

[0004]

The mechanical supercharger is connected to a driving variable pulley via an electromagnetic clutch and a centrifugal variable pulley. For this reason, if the electromagnetic clutch is engaged in a state where the mechanical supercharger is locked by icing, the supercharger driving belt is broken or the supercharger body is damaged. Further, in the engine in which EGR is introduced, the control of the ignition timing and the air-fuel ratio A / F is largely deviated from the required values, and in the worst case, the engine body is damaged.

[0005] To cope with such a situation, the conventional method has been to wait until the thaw is naturally thawed with time and the abnormal state is resolved. This is because it is very rare that the turbocharger is locked by such icing, but the main reason is that there is no means for detecting whether or not icing is performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a mechanical supercharger capable of detecting an abnormal state in which the mechanical supercharger cannot rotate due to icing or the like. An object of the present invention is to provide an abnormality detection device.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, an apparatus for detecting an abnormality of a mechanical supercharger according to the present invention cuts off a drive transmission to a drive transmission system between an engine output shaft and a mechanical supercharger.
A throttle valve provided upstream of the supercharger, and a rotation of the supercharger detected in the intake system provided with a bypass passage of the supercharger having a passage opening / closing valve in the intake system. Means and OF of its drive transmission system prior to driving the turbocharger
A valve control means for narrowing the passage opening / closing valve of the bypass passage under the F state, and abnormality determining means for determining an abnormality of the supercharger based on the presence or absence of rotation of the supercharger by operation of both means. (Claim 1).

In this case, it is possible to provide a temperature detecting means for detecting the temperature of the supercharger, and to determine the abnormality of the supercharger when the temperature of the supercharger is lower than a predetermined value. Item 2).

Further, as a specific configuration, when the engine is started, the bypass valve is opened and then the abnormality of the supercharger is determined. It is preferable to determine the abnormality of the feeder and allow the drive transmission of the drive transmission system when the result of the determination indicates no abnormality.

[0010]

In the first aspect, when the on-off valve of the bypass passage is narrowed, the pressure difference between the front and rear of the supercharger increases due to the negative suction pressure of the engine. Rotate by difference. Therefore, when a rotation signal is not obtained by the turbocharger rotation detecting means when the opening / closing valve of the bypass passage is throttled, the turbocharger is stuck for some reason, including icing, and the rotation occurs. It can be determined that the vehicle is in an abnormal state where it does not move.

As described above, the first aspect of the present invention determines whether the supercharger is stuck abnormally due to the introduction of an additional intake gas (EGR, blow bar), etc., based on the presence or absence of rotation of the supercharger due to the negative suction pressure of the engine. Therefore, the sticking of the turbocharger can be easily detected without providing a separate abnormality determination sensor or the like.

The above-mentioned rotation phenomenon has been confirmed by the present inventors, and the differential pressure required for rotation (idling) of the supercharger 6 varies depending on the type of the supercharger, but is about 100 mm.
Hg is enough. This pressure difference increases as the degree of throttle of the on-off valve approaches the fully closed position, which is advantageous for the purpose of rotating the supercharger. However, it is inconvenient to narrow the bypass passage so as to completely close it, unless there are a plurality of bypass passages for the turbocharger. This is because, when the turbocharger is icing, the intake air amount is drastically reduced below the amount determined by the throttle valve, which hinders the original operation of the engine. Therefore, in practice, the degree of throttle of the bypass passage opening / closing valve is determined, firstly, by a pressure difference required for rotation before and after the supercharger, and secondly, in an abnormal state where the supercharger does not rotate. However, a minimum intake air flow is secured downstream of the turbocharger so that the vehicle can travel without a so-called engine stall.
You need to meet two conditions.

[0013] When the cause of the above-mentioned abnormal fixation of the turbocharger is caused by icing, unlike the case of other causes, the icing state is released by a subsequent rise in the temperature of the engine room, and the turbocharger is normally used. Possibility to recover to possible state is strong. Therefore, it is technically important to detect a case where the non-rotation state is caused by icing while distinguishing it from a case due to other causes.

Therefore, a second aspect is provided with means for detecting the temperature of the supercharger. Here, the term "temperature of the supercharger" means not only a case where the internal temperature or the casing temperature of the supercharger is directly detected by the sensor, but also a case where the temperature is indirectly detected by calculation or the like from the temperature of other parts. Is also included. If the temperature of the supercharger is higher than a predetermined value (for example, 0 ° C.), it is unlikely that at least an abnormality due to icing occurs. Therefore, by assuming that the supercharger abnormality is determined when the temperature of the supercharger is equal to or lower than the predetermined value, the abnormality of the supercharger caused by icing due to the intake additional gas of the supercharger is detected. You can do it.

According to a third aspect of the invention, when it is determined in the first time that the abnormality of the supercharger is abnormal, the final abnormality determination is not immediately performed, but the temperature of the supercharger is increased due to a rise in the temperature of the engine room or the like. The process waits until the temperature rises to a predetermined value (0 ° C.) at which the icing state will be released, and at that time, it is determined again whether or not the supercharger is abnormal. If the result of the determination again is not abnormal, it can be determined that the supercharger abnormality at the time of the first abnormality determination is caused by icing. This allows the drive transmission by the electromagnetic clutch in the supercharging region in the control.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

In FIG. 1, an intake system 2 of an engine body 1 is shown.
In the intake pipe 2a, the air cleaner 3,
Air flow meter 4, throttle valve 5, mechanical supercharger 6,
An intercooler 7 is provided. The intake pipe 2a is provided with a bypass passage 8 for bypassing the mechanical supercharger 6, and a bypass passage opening / closing valve (ABV valve: air bypass valve) 9 is provided in the bypass passage 8. . Reference numeral 10 denotes an exhaust system, and reference numeral 11 denotes a piping portion for introducing EGR gas into the intake system 2 downstream of the throttle valve 5;
Reference numeral 2 denotes a pipe section for supplying blow-by gas upstream and downstream of the throttle valve 5. The blow-by is placed downstream of the throttle valve 5 in a low load region and upstream of the throttle valve 5 in a high load state. In any case, EGR
As in the case of gas, it is introduced into the intake system 2 upstream of the supercharger.

The mechanical supercharger 6 has an electromagnetic clutch 13.
And an engine output shaft 14 via a centrifugal variable pulley (not shown). That is, the engine output shaft 1
4 has a drive transmission system for turning the mechanical supercharger 6, and has an electromagnetic clutch 13 as a means for interrupting and connecting the drive transmission of the drive transmission system. The electromagnetic clutch 13 is cut in a low-speed / low-load region and the supercharging is stopped, and the clutch is turned on in other regions.

A control device 15 controls the throttle opening of the bypass passage opening / closing valve 9 and the on / off operation of the electromagnetic clutch 13, and is mainly constituted by a microprocessor. Numeral 16 denotes a supercharger rotation detecting means for detecting the presence or absence of rotation of the supercharger 6, which here comprises an electromagnetic pickup attached to the supercharger rotor shaft, and its output signal is supplied to the control device 15
Has been entered. As an input signal of the control device 15,
In addition to the signal from the turbocharger rotation detecting means 16, there are signals from an engine speed sensor 17 and a throttle opening sensor 18, and furthermore, the intake air temperature 19 of the supercharger obtained from known sensors and the like. Data such as the discharge temperature 20 of the feeder and the water temperature 21 of the engine are also input.

Prior to driving the supercharger 6, the control device 15 controls the bypass passage opening / closing valve 9 while the drive transmission system is in the OFF state.
By operating the valve control means for reducing the flow area of the bypass passage 8 and the valve control means and the supercharger rotation detecting means 16, the presence or absence of the rotation of the supercharger 6 is determined. Abnormality determination means for determining the abnormality of.

When the engine is started first in the morning, the electromagnetic clutch 13 is still in the OFF state during the initial period of the initial starting state or the low load state. Normally, when the engine enters a supercharging state, the electromagnetic clutch is engaged. The valve control unit is a control unit that throttles the bypass passage opening / closing valve 9 prior to the driving of the supercharger 6 and, therefore, when the supercharger drive transmission system is in the OFF state.

However, "before the supercharger 6 is driven" is a broad concept. For example, when the supercharger 6 enters a supercharging state in which the electromagnetic clutch should be turned on at once, the controller 1
Reference numeral 5 indicates that the electromagnetic clutch is forcibly maintained in the OFF state until the control for narrowing the bypass passage opening / closing valve 9 is completed, but this also includes the forcible OFF state under this control state.

The expression “throttle” the bypass passage opening / closing valve 9 means that when one bypass passage 8 is provided, if the bypass passage 8 is completely closed, the intake air amount is reduced when the turbocharger 6 is icing. Since the engine drastically decreases below the amount set by the throttle valve 5 and a problem arises in the original operation of the engine, even when the supercharger 6 does not move, the so-called minimum intake air flow that allows the vehicle to run without stalling is passed. This is because it is necessary to secure it downstream of the feeder. Therefore, if such a minimum intake air flow is ensured downstream of the supercharger, the bypass passage opening / closing valve 9 may be completely closed. For example, although a bypass passage 22 is provided so as to bypass the throttle valve 5 and the idle speed is adjusted by the ISC valve, the bypass passage 23 is extended as indicated by a dotted line in the drawing. By setting the bypass passage 23 from the upstream of the throttle valve 5 to the downstream of the supercharger, it is possible to allow the bypass passage on-off valve 9 to be completely closed. In short, when there are a plurality of bypass passages for the turbocharger 6, the flow opening degree may be narrowed down in all of them. In this sense, the term “throttle” in the path passage opening / closing valve 9 includes a state in which the valve is completely closed.

Now, as described above, the bypass passage opening / closing valve 9
When the engine speed is reduced, the pressure difference between the front and rear of the supercharger 6 increases due to the suction work of the engine, and the mechanical supercharger 6 rotates if it is in a normal state without sticking such as icing. This rotation phenomenon has been confirmed by the present inventors, and the differential pressure required for rotation (idling) of the supercharger 6 varies depending on the type of the supercharger, but about 100 mmHg is sufficient. Therefore, the degree of the throttle of the bypass passage opening / closing valve 9 is actually deeper than the degree that a differential pressure higher than the differential pressure necessary for such rotation is generated before and after the supercharger 6 (the flow area is smaller). ) Aperture, however, as described above, it is required that the aperture be loose enough to ensure that the engine runs without stopping. When the bypass passage opening / closing valve 9 is squeezed, the abnormality judging means detects the turbocharger rotation detecting means 1.
At 6, it is determined whether or not it appears in the rotation signal. If the rotation signal does not appear on the turbocharger rotation detecting means 16 even if the pressure difference becomes large to some extent, it is determined that there is some fixing abnormality in the supercharger 6, including the case of icing, and the rotation is determined. If this is the case, it is determined to be normal.

When the cause of the sticking abnormality of the turbocharger 6 is caused by icing, unlike the case of other causes, the temperature rise in the engine room and the flow of air in the turbocharger and the lapse of time, unlike the case of other causes. There is a strong possibility that the frozen state will be released and the turbocharger will be restored to a state where it can be used normally. Therefore, a supercharger temperature detecting means for detecting the temperature of the supercharger is provided in order to detect the case where the non-rotation state is caused by icing differently from the case where the mechanical state is caused by mechanical lock or the like. Here, the term "temperature of the supercharger" means not only a case where the internal temperature or the casing temperature of the supercharger is directly detected by the sensor, but also a case where the temperature is indirectly detected by calculation or the like from the temperature of other parts. Is also included.

In the case of the present embodiment, the temperature of the supercharger is calculated from the intake air temperature 19 of the supercharger and the water temperature 21 of the engine, and the temperature is in a temperature range equal to or lower than a predetermined value (0 ° C.). Only at step (a), the abnormality of the turbocharger is determined. However, the temperature of the supercharger can be determined in consideration of the discharge temperature 20 of the supercharger. In the present embodiment, the predetermined temperature at which the abnormality determination of the supercharger is performed is set to 0 ° C. because the temperature of the supercharger is set to the predetermined value 0.
If the temperature is higher than 0 ° C, it is impossible that icing has occurred in the turbocharger, and it is considered that the sticking is caused by another mechanical lock or the like. Can be changed.

Next, a specific control method will be described with reference to FIG.

At the start of the engine, before the supercharger 6 is driven, the bypass passage opening / closing valve 9 is throttled to near the fully closed state with the electromagnetic clutch 13 turned off (step 31). Is monitored to check whether or not the turbocharger 6 is rotating (step 32). If the supercharger 6 rotates, the system is determined to be normal, and normal control is started (step 33). In the normal control, for example, the electromagnetic clutch 13 is cut in a low rotation / low load region to stop the supercharging, and in other regions, the clutch is turned on to secure a sufficient intake air amount on the low rotation side while maintaining a high intake air amount. On the rotating side, control is performed to suppress an excessive increase in the supercharging pressure.

When the turbocharger 6 does not rotate, it can be determined that the turbocharger is locked for some reason. Therefore, in order to determine whether or not the cause is caused by icing, it is checked whether or not the temperature of the supercharger is a low temperature of 0 ° C. or less (step 34). It is determined that the supercharger body or the control system is abnormal (step 35), the bypass passage opening / closing valve 9 is fully opened, the drive transmission to the supercharger is turned off (step 36), and a warning is issued by an alarm mechanism. By fully opening the bypass passage opening / closing valve 9, natural intake is performed without passing through the supercharger 6, and normal operation of the engine is ensured. In addition, drive transmission of the supercharger is normally performed even in a supercharged region. By not allowing the electromagnetic clutch included in the system to be turned on, it is possible to avoid running out of belt and damage to the supercharger main body.

Next, in step 34, when the temperature of the supercharger is 0 ° C. or less, it is considered that icing has occurred, and thus control of supercharger OFF (electromagnetic clutch OFF)
(Step 37), the bypass passage opening / closing valve 9 is maintained.
To a minimum necessary opening degree that does not stop the engine (specifically, a degree that the vehicle can run to some extent) (Step 3).
8) It is checked whether the supercharger rotates (step 39). If the supercharger does not rotate, the process returns to step 34 because icing is still performed, and the control of turning off the electromagnetic clutch is continued until the supercharger rotates, that is, until the engine room is warmed up and the icing is released ( Step 34
To 39). Thereafter, if the supercharger starts to rotate, it is determined that the ice has melted and has returned to the normal state, so that the normal control is started as in step 33 (step 40).

[0031]

As described above, according to the present invention, the following excellent effects can be obtained.

(1) According to the first aspect, when the on-off valve of the bypass passage is throttled, the supercharger rotates if it is normal, and does not rotate if there is sticking such as icing. In any case, an abnormal state in which the turbocharger does not rotate can be detected. This is because the sticking abnormality of the turbocharger due to the introduction of additional gas (EGR, blow bar) etc.
Since the determination is made based on the presence or absence of the rotation of the supercharger due to the suction negative pressure of the engine, it is possible to easily detect the sticking of the supercharger without providing a separate abnormality determination sensor or the like.

(2) According to the second aspect, it is promised that the abnormality determination of the supercharger is performed when the temperature of the supercharger is lower than the predetermined value (for example, 0 ° C.). It is possible to detect an abnormality of the supercharger caused by icing due to the intake additional gas or the like.

(3) According to the third aspect, when it is determined in the first time that the abnormality of the supercharger is abnormal, the final abnormality determination is not immediately performed, and the temperature of the supercharger is reduced to the engine room. It is necessary to wait until the temperature rises to a predetermined value (0 ° C.) at which the icing condition will be released due to a rise in the temperature of the supercharger. The cause of the abnormality can be clearly distinguished and detected between the case of icing and the case of another cause. If the result of the determination again is not abnormal, it can be determined that the supercharger abnormality at the time of the first abnormality determination was caused by icing. It is possible to allow the electromagnetic clutch to be turned on in the supercharging region at the time. That is, even when the engine is stopped from a supercharged state and left overnight overnight in extremely cold weather, if the icing is occurring in the supercharger, the supercharger is not rotated until it is released. It is possible to prevent the occurrence of accidents such as cutting of the driving belt and breakage of the supercharger body.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an abnormality detection device according to the present invention.

FIG. 2 is a flowchart illustrating a control example of the abnormality detection device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 2 Intake system 2a Intake pipe 3 Air cleaner 4 Air flow meter 5 Throttle valve 6 Mechanical supercharger 7 Intercooler 8 Bypass passage 9 Bypass passage opening / closing valve 13 Electromagnetic clutch 14 Engine output shaft 15 Control device 16 Turbocharger rotation Detection means (electromagnetic pickup) 19 Intake air temperature 20 Discharge temperature 21 Water temperature

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 39/16 F02B 33/00 F02B 39/12

Claims (3)

(57) [Claims] 1. A drive transmission system between an engine output shaft and a mechanical supercharger is provided with a means for interrupting and transmitting drive transmission, and an intake system is provided with a bypass passage of the supercharger having a passage opening / closing valve. A throttle valve provided upstream of the supercharger, a means for detecting rotation of the supercharger, and a passage opening / closing valve for a bypass passage under an OFF state of a drive transmission system prior to driving of the supercharger. A turbocharger abnormality detecting device, comprising: valve control means for restricting pressure; and abnormality determining means for determining abnormality of the supercharger based on the presence or absence of rotation of the supercharger by operation of both means. . 2. The machine according to claim 1, further comprising a temperature detecting means for detecting a temperature of the supercharger, wherein an abnormality of the supercharger is determined when the temperature of the supercharger is lower than a predetermined value. Abnormality detection device for turbocharger. 3. When the engine is started, the bypass valve is opened and then the abnormality of the supercharger is determined. If the abnormality of the supercharger occurs, the abnormality of the supercharger is determined again when the temperature of the supercharger rises to a predetermined value. 3. The abnormality detection device for a mechanical supercharger according to claim 1, wherein the determination is made, and the drive transmission of the drive transmission system is permitted when the determination result indicates no abnormality.