JPH06221175A - Abnormality detecting device for mechanical supercharger - Google Patents

Abstract

PURPOSE:To perform detection of an abnormal state wherein the mechanical supercharger of an engine is brought into a non-rotatable state owing to icing. CONSTITUTION:A bypass passage 8 is arranged to the mechanical supercharger 6 of an intake air system 2 and a pickup 16 to detect rotation of the supercharger 6 and a means to detect the temperature of the supercharger are provided. In prior to driving of the supercharger 6, the passage on-off valve 9 of a bypass passage 8 is throttled under the OFF-state of the electromagnetic clutch 13 of a drive transmission system. The presence of the sticking state of the supercharger is discriminated from whether the supercharger 6 is rotated by means of a difference in a pressure produced between positions situated upper stream and downstream from the supercharger 6 owing to a negative pressure. In this case, an abnormality discriminating means to decide that sticking owing to icing occurs in a case the supercharger 6 is not rotated when the temperature of the supercharger is 0 deg.C or lower is provided.

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 a device 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 its intake system, blow-by gas from the EGR means of the type in which exhaust gas is returned to the upstream side of the mechanical supercharger or the crankcase of the engine is overloaded. Some have a means for returning to the upstream of the feeder.

[0003] In the case of an engine in which additional gas such as intake air is fed to the upstream side as described above, when the engine is stopped from the supercharging state and left for one night in extremely cold weather, the water inside the mechanical supercharger is frozen at night. So-called icing may occur, and the engine may not be able to rotate when the engine is started the next morning. This is because the EGR gas or the like contains a large amount of water, and the water 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 the drive side variable pulley via an electromagnetic clutch and a centrifugal type variable pulley. Therefore, if the electromagnetic clutch is engaged while the mechanical supercharger is locked by icing, the supercharger drive belt may be broken or the supercharger body may be damaged. Further, in an engine in which EGR is introduced, the control of the ignition timing and the air-fuel ratio A / F largely deviates from the required values, and in the worst case, the engine body is damaged.

In the past, this situation has been dealt with by waiting until the abnormal state is resolved by thawing naturally over time. This is because it is extremely rare for the supercharger to lock due to such icing, but the main reason is that there was no means for detecting whether or not icing was performed.

The present invention has been made in view of the above problems, and an object thereof 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. To provide an abnormality detecting device.

[0007]

In order to achieve the above object, an abnormality detecting device for a mechanical supercharger of the present invention disconnects drive transmission from a drive transmission system between an engine output shaft and a mechanical supercharger.
A throttle valve provided upstream of the supercharger and rotation of the supercharger are detected in the intake system provided with a bypass passage of the supercharger provided with a passage opening / closing valve in the intake system. Means and OF of its drive transmission system prior to driving the supercharger
A configuration is provided that includes valve control means for narrowing the passage opening / closing valve of the bypass passage in the F state, and abnormality determination means for determining abnormality of the supercharger based on the presence or absence of rotation of the supercharger by the operation of both means. There is (claim 1).

In this case, further, a temperature detecting means for detecting the temperature of the supercharger may be provided so that the abnormality of the supercharger can be determined when the temperature of the supercharger is below a predetermined value. Item 2).

Further, as a specific configuration, when the engine is started, the bypass passage opening / closing valve is opened, and then an abnormality of the supercharger is discriminated, and at the time of abnormality, when the temperature of the supercharger rises to a predetermined value, the supercharger is again superposed. It is preferable to determine the abnormality of the feeder and allow the drive transmission of the drive transmission system when the determination result shows no abnormality (claim 3).

[0010]

According to the present invention, when the on-off valve of the bypass passage is throttled, the suction negative pressure of the engine causes a large pressure difference between the front and rear of the supercharger, and the mechanical supercharger is operated under pressure unless icing is stuck. Rotate due to the difference. Therefore, when the opening and closing valve of the bypass passage is throttled, if the rotation signal is not obtained from the supercharger rotation detection means, the supercharger is stuck due to some cause, including the case of icing, and is rotated. It is possible to determine that there is an abnormal state that does not move.

As described above, according to the first aspect of the present invention, the abnormality in sticking of the supercharger due to the introduction of the intake additional gas (EGR, blower) or the like is determined by the presence / absence of rotation of the supercharger due to the suction negative pressure of the engine. Therefore, the fixation of the supercharger can be easily detected without separately providing an 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 is about 100 mm although it varies depending on the type of supercharger.
Hg is sufficient. This pressure difference increases as the degree of throttle of the on-off valve approaches to the fully closed state, which is advantageous for the purpose of rotating the supercharger. However, deeply narrowing the bypass passage so as to completely close it is inconvenient unless there are a plurality of bypass passages for the supercharger. This is because when the supercharger is icing, the intake air amount is drastically reduced below the amount determined by the throttle valve, and the original operation of the engine is hindered. Therefore, in practice, the degree of throttling of the bypass passage opening / closing valve depends on whether the pressure difference necessary for rotation is generated before and after the supercharger, and secondly in an abnormal state where the supercharger does not rotate. Even so, the so-called minimum intake flow is ensured to the downstream side of the supercharger to the extent that it can travel without being stalled.
There are two conditions that must be met.

By the way, when the cause of the fixing abnormality of the supercharger is icing, unlike the other causes, the icing state is released by the subsequent temperature rise in the engine room and the supercharger is normally used. There is a strong possibility of recovering to a possible state. Therefore, it is technically important to detect the case where the non-rotating state is caused by icing separately from the cases caused by other causes.

Therefore, the second aspect provides means for detecting the temperature of the supercharger. Here, the "supercharger temperature" means not only the case where the internal temperature of the supercharger or the casing temperature is directly detected by a sensor, but also the case where the temperature is indirectly detected by calculation from the temperature of other parts. It also includes. If the temperature of the supercharger is higher than a predetermined value (for example, 0 ° C.), it is unlikely that the abnormality is due to icing. Therefore, by promising that the abnormality determination of the supercharger will be performed when the temperature of the supercharger is less than or equal to this predetermined value, the abnormality of the supercharger due to the icing due to the intake additional gas of the supercharger is detected. It is possible.

According to a third aspect of the present invention, when it is determined that the abnormality has been detected in the abnormality of the post-supercharger for the first time, the final abnormality determination is not immediately made, but the temperature of the supercharger is increased due to a temperature rise in the engine room or the like. The process waits until the freezing state rises to a predetermined value (0 ° C.) that will be released, and at that time, the presence or absence of abnormality of the supercharger is determined again. If the determination result again is not abnormal, it can be determined that the turbocharger abnormality at the time of the first abnormality determination is due to icing, so that the icing state is considered to have been canceled, This is to allow drive transmission by closing the electromagnetic clutch in the supercharging region in control.

[0016]

The present invention will be described below with reference to the illustrated embodiments.

In FIG. 1, an intake system 2 of the engine body 1
In the intake pipe 2a of the air cleaner 3,
Air flow meter 4, throttle valve 5, mechanical supercharger 6,
An intercooler 7 is provided. A bypass passage 8 that bypasses the mechanical supercharger 6 is provided in the intake pipe 2a, and a bypass passage opening / closing valve (ABV valve: air bypass valve) 9 is provided in the bypass passage 8. . Reference numeral 10 is an exhaust system, 11 is a piping portion for introducing EGR gas into the intake system 2 on the downstream side of the throttle valve 1,
Reference numeral 2 denotes a pipe portion for introducing blow-by gas on the upstream side and the downstream side of the throttle valve 5. The blow-by is put downstream of the throttle valve 5 in the low load region and upstream of the throttle valve 5 in the high load state. In any case, EGR
As in the case of gas, it is admitted 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 rotating the mechanical supercharger 6, and has an electromagnetic clutch 13 as means for disconnecting and continuing drive transmission of the drive transmission system. The electromagnetic clutch 13 is cut off in a low rotation / low load range to stop supercharging, and is turned on in other regions.

Reference numeral 15 is a control device for controlling the throttle opening degree of the bypass passage opening / closing valve 9 and the connection / disconnection of the electromagnetic clutch 13, which is mainly composed of a microprocessor. Reference numeral 16 denotes a supercharger rotation detecting means for detecting whether or not the supercharger 6 has rotated, and here it is an electromagnetic pickup attached to the rotor shaft of the supercharger, and its output signal is the control device 15.
Has been entered in. As an input signal of the control device 15,
In addition to the signal from the supercharger rotation detection means 16, there are signals from the engine speed sensor 17 and the throttle opening sensor 18, and the intake air temperature 19 of the supercharger and 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 controller 15 controls the bypass passage opening / closing valve 9 while the drive transmission system is in the OFF state.
By controlling the valve control means and the supercharger rotation detection means 16 so as to reduce the flow area of the bypass passage 8 and whether or not the supercharger 6 is rotated. And an abnormality determining means for determining the abnormality.

When the engine is started first thing in the morning, the electromagnetic clutch 13 is still in the OFF state in the initial period of the initial starting state or the low load state. Then, normally, when the engine enters the supercharging state, the electromagnetic clutch is engaged. The valve control means is a control means for narrowing the bypass passage opening / closing valve 9 prior to such driving of the supercharger 6 and thus in the OFF state of the supercharger drive transmission system.

However, the term "prior to driving the supercharger 6" is a broad concept, and for example, when the electromagnetic clutch enters the supercharging state in which it should be turned on at once, the control device 1
No. 5 compulsorily maintains the electromagnetic clutch in the OFF state until the control to throttle the bypass passage opening / closing valve 9 is completed, but also includes a compulsory OFF state under such a control state.

The expression that the bypass passage opening / closing valve 9 is "throttled" means that when the bypass passage 8 is one and the bypass passage 8 is completely closed, the intake air amount is increased when the supercharger 6 is icing. Even if the turbocharger 6 does not work, the minimum intake air flow to the extent that it can run without stall is exceeded because the engine operation will be reduced by the amount that is drastically reduced below the throttle valve 5. This is because it is necessary to secure it on the downstream side of the feeder. Therefore, the bypass passage opening / closing valve 9 may be completely closed as long as the minimum intake air flow is secured downstream of the supercharger. For example, although the bypass passage 22 is normally 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 forming the bypass passage 23 from the upstream side of the throttle valve 5 to the downstream side of the supercharger, the bypass passage opening / closing valve 9 can be completely closed. In short, in the case where there are a plurality of bypass passages for the supercharger 6, the flow passage opening may be totally throttled in the bypass passages. In this sense, the concept of "throttle" in the pass passage opening / closing valve 9 includes a state where the valve is completely closed.

Now, as described above, the bypass passage opening / closing valve 9
When the throttle valve is throttled, the pressure difference before and after the supercharger 6 increases due to the suction work of the engine, and the mechanical supercharger 6 rotates in a normal state where there is no 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 throttling of the bypass passage opening / closing valve 9 is actually deeper than the differential pressure required for such rotation before and after the supercharger 6 (the distribution area is small). ) It is required to be a throttle, but as described above, a throttle that is gentle enough to ensure a state in which the engine runs without stopping. The abnormality determination means is the supercharger rotation detection means 1 when the bypass passage opening / closing valve 9 is throttled.
It is judged whether or not it appears in the rotation signal in 6. If the rotation signal does not appear in the supercharger rotation detection means 16 even if the pressure difference becomes large to some extent, it is determined that there is some sticking abnormality in the supercharger 6, including the case of icing, and rotation is performed. If it does, it is judged to be normal.

When the cause of the sticking abnormality of the supercharger 6 is icing, unlike the other causes, the temperature rise in the engine room, the flow of air in the supercharger, and the passage of time will occur. There is a strong possibility that the frozen state will be released and the turbocharger will be restored to a normal state. Therefore, supercharger temperature detecting means for detecting the temperature of the supercharger is provided in order to detect the case where the non-rotating state is caused by icing separately from the cases caused by other mechanical locks. Here, the "supercharger temperature" means not only the case where the internal temperature of the supercharger or the casing temperature is directly detected by a sensor, but also the case where the temperature is indirectly detected by calculation from the temperature of other parts. It also includes.

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 within a temperature range below a predetermined value (0 ° C.). Only in the case of the supercharger abnormality determination. However, the temperature of the supercharger can be determined by further considering the discharge temperature 20 of the supercharger. In the present embodiment, the predetermined temperature for determining abnormality of the supercharger is set to 0 ° C. because the temperature of the supercharger is a predetermined value of 0.
If the temperature is higher than ℃, icing cannot occur in the turbocharger, and it is considered that the icing is due to other causes such as mechanical lock. Can be changed.

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

Before the supercharger 6 is driven, the bypass passage on-off valve 9 is throttled to near full closure (step 31) when the engine is started and the supercharger 6 is driven. Is monitored to check whether the supercharger 6 is rotating (step 32). If the supercharger 6 rotates, the system is judged to be normal, and normal control is entered (step 33). In such normal control, for example, the electromagnetic clutch 13 is cut to stop supercharging in the low rotation / low load range, and the clutch is turned on in the other regions to ensure high intake while ensuring a sufficient intake amount on the low rotation side. On the rotation side, control is performed so as to suppress an excessive increase in boost pressure.

When the supercharger 6 does not rotate, it can be determined that the supercharger is locked for some reason. Therefore, in order to determine whether or not the cause is icing, it is checked whether or not the temperature of the supercharger is a low temperature of 0 ° C. or lower (step 34). If NO, it is not due to icing. It is judged that the main body of the supercharger 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 an alarm mechanism warns. By fully opening the bypass passage opening / closing valve 9, natural intake is performed without the supercharger 6 to ensure normal operation of the engine, and drive transmission of the supercharger is achieved even in the normal supercharging region. By not allowing the electromagnetic clutch in the system to turn on, it is possible to avoid belt breakage and damage to the turbocharger body.

Next, in step 34, when the temperature of the supercharger is 0 ° C. or less, it is considered that icing is occurring, so control of turning off the supercharger (electromagnetic clutch OFF).
(Step 37) while maintaining the
Throttle to the minimum required opening that does not stop the engine (specifically, the vehicle can run to some extent) (Step 3
8) Then, it is checked whether the supercharger rotates (step 39). If the supercharger does not rotate, the icing is still in progress, so the process returns to step 34, and the electromagnetic clutch OFF control is continued until the supercharger rotates, that is, until the engine room is warmed up and the icing is released ( Step 34
~ 39). After that, if the supercharger starts to rotate, it is determined that the icing has been thawed and the normal state has been restored, 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 opening / closing valve of the bypass passage is throttled, the turbocharger rotates if it is normal and does not rotate if icing is stuck. Including the case, it is possible to detect an abnormal state in which the supercharger does not rotate. This is due to the abnormality in the turbocharger sticking due to the introduction of intake additional gas (EGR, blower), etc.
Since the determination is made based on whether or not the supercharger is rotated due to the negative suction pressure of the engine, it is possible to easily detect the fixation of the supercharger without separately providing an 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 freezing due to the intake additional gas or the like.

(3) According to claim 3, when it is judged that the abnormality has occurred in the abnormality determination of the rear supercharger for the first time, the final abnormality determination is not immediately made, and the temperature of the supercharger is determined as the engine room. It is necessary to wait until the temperature rises to a predetermined value (0 ° C) that will release the freezing state due to temperature rise, etc., and at that point again determine whether there is an abnormality in the supercharger. The cause of the abnormality can be clearly distinguished and detected depending on whether the cause is icing or another cause. If the result of the second determination is not abnormal, it can be determined that the turbocharger abnormality at the time of the first abnormality determination was due to icing. Therefore, it is considered that the icing state has been released, and normal control is performed. It is possible to allow the electromagnetic clutch to be closed in the supercharging range. That is, even when the engine is stopped from the supercharging state and left overnight during extremely cold weather, if the supercharging machine causes icing, the supercharging machine will not rotate until it is released. It is possible to prevent the occurrence of accidents such as cutting of the drive belt and damage to the supercharger body.

[Brief description of drawings]

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

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

[Explanation 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 Open / Close Valve 13 Electromagnetic Clutch 14 Engine Output Shaft 15 Control Device 16 Supercharger Rotation Detection means (electromagnetic pickup) 19 Intake temperature 20 Discharge temperature 21 Water temperature

Claims (3)

[Claims] 1. A drive transmission system between an engine output shaft and a mechanical supercharger is provided with means for disconnecting and connecting drive transmission, and an intake system is provided with a bypass passage of the supercharger having a passage opening / closing valve. In the above, a throttle valve provided upstream of the supercharger, a means for detecting rotation of the supercharger, and a passage opening / closing valve for the bypass passage under the OFF state of the drive transmission system prior to driving the supercharger. An abnormality detection device for a mechanical supercharger, comprising: a valve control means for squeezing the valve; and an abnormality determination means for determining an abnormality of the supercharger based on whether or not the supercharger is rotated by the operation of both means. . 2. The machine according to claim 1, further comprising temperature detecting means for detecting the temperature of the supercharger, and determining the abnormality of the supercharger when the temperature of the supercharger is below a predetermined value. Type abnormality detection device for supercharger. 3. When the engine is started, the bypass passage opening / closing valve is opened, and then the abnormality of the supercharger is determined. When the abnormality occurs, the abnormality of the supercharger is detected again when the temperature of the supercharger rises to a predetermined value. 3. The abnormality detecting 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 shows no abnormality.