KR102250296B1 - Apparatus and method for monitering cylinder imbalance of multi-cylinder internal combustion engine - Google Patents

Abstract

The present invention monitors the deviation of each cylinder (cylinder imbalance) and corrects the amount of fuel in response to the deviation, thereby improving the fuel efficiency and performance of a vehicle, and reducing exhaust gas, a cylinder deviation monitoring device for a multi-cylinder internal combustion engine, and the like. It's about the method.
The apparatus for monitoring cylinder deviation of a multi-cylinder internal combustion engine according to the present invention includes: a diagnostic unit for diagnosing a failure of each cylinder by monitoring the deviation of each cylinder using an engine speed roughness and a lambda value; And a control unit that transmits vehicle and engine information to the diagnosis unit and controls ignition of each cylinder according to a deviation of each cylinder diagnosed by the diagnosis unit.

Description

A device for monitoring cylinder deviation of a multi-cylinder internal combustion engine and its method {APPARATUS AND METHOD FOR MONITERING CYLINDER IMBALANCE OF MULTI-CYLINDER INTERNAL COMBUSTION ENGINE}

The present invention monitors the deviation of each cylinder (cylinder imbalance) and corrects the amount of fuel in response to the deviation, thereby improving the fuel efficiency and performance of a vehicle, and reducing exhaust gas, a cylinder deviation monitoring device for a multi-cylinder internal combustion engine, and the like. It's about the method.

The multi-cylinder internal combustion engine is an internal combustion engine having a plurality of cylinders and can improve output and displacement.

The cylinder imbalance of the multi-cylinder internal combustion engine may occur, and the deviation between the cylinders may be caused by misfire in each cylinder due to a cylinder defect, an intake air leakage, or an injector failure.

Due to the misfire of such individual cylinders, variations in the amount of fuel and rotational speed (number of revolutions) may occur between the plurality of cylinders, and the output, performance, and fuel economy of the internal combustion engine may be deteriorated, as well as exhaust gases. It can be high.

Accordingly, the internal combustion engine of the prior art was made in a manner of determining an air-fuel ratio imbalance between the cylinders by detecting more than the air-fuel ratio of individual cylinders, and correcting the fuel injection amount according to the determined air-fuel ratio imbalance.

However, the conventional air-fuel ratio imbalance determination method has a disadvantage in that a method of detecting an air-fuel ratio abnormality of an individual cylinder is complicated, so that a detection time is required for a long time, and the detection accuracy is deteriorated.

US 9097193

The present invention was devised in consideration of the above points, and diagnoses whether each cylinder has a failure while accurately and quickly monitoring the deviation of each cylinder using the engine speed roughness and lambda value. The purpose of this is to provide an apparatus and method for monitoring deviation between cylinders of a multi-cylinder internal combustion engine that can improve fuel efficiency and performance of vehicles and reduce emissions by correcting the amount of fuel in response to the monitored deviation. There is this.

One aspect of the present invention for achieving the above object is an apparatus for monitoring cylinder deviation of a multi-cylinder internal combustion engine,

A diagnostic unit for diagnosing a failure of each cylinder by monitoring the deviation of each cylinder using an ENGINE SPEED ROUGHNESS and a lambda value; And

And a control unit that transmits vehicle and engine information to the diagnosis unit and controls ignition of each cylinder according to a deviation of each cylinder diagnosed by the diagnosis unit.

A crank angle sensor and an oxygen sensor are connected to the diagnosis unit,

The diagnosis unit receives the engine speed roughness of each cylinder calculated by the crank angle sensor and a lambda value of each cylinder calculated by the oxygen sensor,

The engine speed roughness of each cylinder and the lambda value of each cylinder may be used to monitor the deviation of each cylinder, thereby diagnosing the failure of each cylinder.

The diagnosis unit calculates the deviation of the engine speed roughness of each cylinder and the deviation of the lambda value of each cylinder through the engine speed roughness of each cylinder and the lambda value of each cylinder,

The diagnosis unit may be configured to diagnose a failure of each cylinder by monitoring a deviation of each cylinder through a deviation of the calculated engine speed roughness of each cylinder and a deviation of a lambda value of each cylinder.

The deviation of the engine speed roughness of each cylinder may be a difference between the basic engine speed roughness calculated during normal combustion of each cylinder and the engine speed roughness calculated during actual combustion of each cylinder.

The deviation of the lambda value of each cylinder may be a difference value between a basic lambda value calculated during normal combustion of each cylinder and a lambda value calculated during actual combustion of each cylinder.

The injectors of each cylinder are connected to the control unit, and the injectors of each cylinder may be controlled according to information monitored by the diagnosis unit.

The diagnostic unit reduces the amount of fuel injected from the injector of each cylinder until the deviation of the engine speed roughness of each cylinder reaches a set value, compares the deviation of the lambda value of each cylinder with a reference value, and performs normal combustion of each cylinder or Abnormal combustion can be judged.

When reducing the amount of fuel until the deviation of the engine speed roughness of any one cylinder reaches the determined value, if the deviation of the lambda value of the corresponding cylinder is lower than the reference value, the corresponding cylinder is determined as an abnormal combustion state. The cylinder can be diagnosed as a failure.

The control unit calculates a corrected fuel amount for the cylinder by using the deviation of the lambda value of the cylinder diagnosed as a failure,

The controller may control the amount of fuel injected from the injector of the corresponding cylinder by using the corrected fuel amount.

Another aspect of the present invention is a cylinder deviation monitoring method of a multi-cylinder internal combustion engine for monitoring the deviation of each cylinder of the multi-cylinder internal combustion engine,

If it is determined that the deviation of each cylinder is diagnosed through the vehicle information, the engine information, and the measured value of the oxygen sensor, the basic engine speed roughness and the basic lambda value of each cylinder are calculated.

Reduces the amount of fuel injected from the injector of the cylinder to be diagnosed,

Calculate the deviation of the engine speed roughness of the cylinder and the deviation of the lambda value of the cylinder,

If the fuel quantity of the cylinder is decreased until the deviation of the engine speed roughness of the cylinder reaches the set value, the deviation of the cylinder's lambda value and the reference value are compared to monitor the deviation of the cylinder and diagnose the failure of the cylinder. I can.

Through the engine speed roughness of each cylinder and the lambda value of each cylinder, the deviation of the engine speed roughness of the cylinder and the deviation of the lambda value of each cylinder can be calculated.

The deviation of the engine speed roughness of each cylinder may be a difference between the basic engine speed roughness calculated during normal combustion of each cylinder and the engine speed roughness calculated during actual combustion of each cylinder.

The deviation of the lambda value of each cylinder may be a difference value between a basic lambda value calculated during normal combustion of each cylinder and a lambda value calculated during actual combustion of each cylinder.

If the deviation of the lambda value of the cylinder is lower than the reference value, the cylinder is diagnosed as a failure.

Using the deviation of the lambda value of the cylinder diagnosed as a failure, the corrected fuel amount for the cylinder is calculated,

The amount of fuel injected from the injector of the cylinder can be controlled using the corrected fuel amount.

According to the present invention, it is possible to monitor the deviation of each cylinder by using the deviation (△ER) of the engine speed roughness of each cylinder and the deviation (△λ) of the lambda value of each cylinder. By diagnosing the failure of each cylinder, the time to diagnose the failure of each cylinder can be significantly reduced, so frequent diagnosis is possible, effectively improving the In-Use Monitoring Performance Ratio (IUMPR), and reducing the fuel quantity deviation of each cylinder. It has the advantage of being able to significantly reduce it.

In addition, the present invention has the advantage of being able to precisely monitor the cylinder deviation of a multi-cylinder internal combustion engine through diagnosis of a failure of a corresponding cylinder and adjustment of an injection amount of an injector.

1 is a block diagram showing a cylinder deviation monitoring apparatus of a multi-cylinder internal combustion engine according to an embodiment of the present invention.
2 shows the relationship between the deviation of the engine speed roughness of each cylinder (ΔER) and the deviation of the lambda value of each cylinder (Δλ) when forcibly reducing the amount of fuel in order to diagnose the deviation of each cylinder. It is a graph.
3 is a diagram illustrating a state in which an average lambda value for a plurality of cylinders is controlled to reach a normal combustion state by increasing the fuel amount of the remaining cylinders when cylinder 1 fails in a four-cylinder internal combustion engine.
4 is a flowchart illustrating a method for monitoring deviation between cylinders of a multi-cylinder internal combustion engine according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, the size of the components, the thickness of the line, and the like shown in the drawings referred to in describing the present invention may be somewhat exaggerated for convenience of understanding. In addition, terms used in the description of the present invention are defined in consideration of functions in the present invention, and thus may vary according to user, operator intention, custom, and the like. Therefore, the definition of this term should be made based on the overall contents of the present specification.

In describing the constituent elements of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), and the like may be used. These terms are for distinguishing the constituent element from other constituent elements, and the nature, order, or order of the constituent element is not limited by the term. In addition, unless otherwise defined, all terms including technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

One aspect of the present invention is a cylinder deviation monitoring apparatus of a multi-cylinder internal combustion engine for monitoring the deviation of each cylinder of a multi-cylinder internal combustion engine having a plurality of cylinders.

Referring to FIG. 1, the cylinder deviation monitoring apparatus of a multi-cylinder internal combustion engine according to an embodiment of the present invention monitors the deviation of each cylinder using an engine speed roughness (ER) and a lambda value. In addition to transmitting vehicle and engine information to the diagnosis unit 10 and the diagnosis unit 10 for diagnosing the fault of the base, the ignition of each cylinder is ignited according to the deviation of each cylinder diagnosed by the diagnosis unit 10. It includes a control unit 20 to control.

The control unit 20 may be an ECU (Electronic Control Unit) of the vehicle, and the control unit 20 provides information on the vehicle such as vehicle speed and engine information such as engine load and engine RPM to the diagnosis unit 10. Can be configured to transmit.

The injector 25 of each cylinder is connected to the control unit 20, and the control unit 20 can control each injector 25 according to the information monitored by the diagnosis unit 10, through which each cylinder is ignited. Can be properly controlled.

A crank angle sensor 11, an oxygen sensor 12, an actuator of an exhaust valve 13, and the like are connected to the diagnosis unit 10. Thereby, the diagnosis unit 10 includes the engine speed roughness (ER _n , n=1, 2, 3...) of each cylinder calculated by the crank angle sensor 11, the oxygen sensor 12, and _{It may be configured to receive a lambda value (λ n} , n = 1, 2, 3...) of each cylinder calculated by the exhaust valve 13. Here, n means the number of the cylinder. For example, in the case of a 4-cylinder, n=1, 2, 3, and 4 may be used, and in the case of an 8-cylinder, n=1, 2, 3, 4, 5, 6, 7, and 8.

In addition, the diagnosis unit 10 may receive vehicle and engine information such as a vehicle speed, an engine load, and an engine RPM by the control unit 20.

The diagnostic unit 10 uses the engine speed roughness ER _{n of} each cylinder and the lambda value λ _n of each cylinder described above to determine the deviation (ΔER) of the engine speed roughness of each cylinder and each cylinder. Calculate the deviation of the lambda value (△λ), and monitor the deviation of each cylinder using the calculated deviation of the engine speed roughness of each cylinder (△ER) and the deviation of the lambda value of each cylinder (△λ). Thus, it can be configured to diagnose the failure of each cylinder. In this case, the diagnosis unit 10 may individually or simultaneously monitor and diagnose the deviation of each cylinder. For example, after diagnosing cylinder 1, the diagnosis unit 10 may sequentially monitor and diagnose cylinders 2 and 3, or individually monitor and diagnose cylinders regardless of the order of cylinders. Can also be monitored and diagnosed at the same time.

According to an embodiment of the present invention, each cylinder imbalance refers to the degree to which the output of each cylinder, lambda, etc., fluctuates during the operation of each cylinder, and the cylinder imbalance of each cylinder is each cylinder (each cylinder imbalance). cylinder) can be monitored by substituting the deviation (difference value) of the engine speed roughness and the deviation (difference value) of the lambda value into a predetermined logic.

Specifically, the deviation of each cylinder may be a deviation of a lambda value of each cylinder calculated according to a deviation (difference value) of roughness of engine rotation speed of each cylinder (a deviation of fuel amount).

The deviation (△ER) of the engine speed roughness of each cylinder is the basic engine speed roughness (ER _B ) calculated during normal combustion of each cylinder and the engine speed roughness calculated during actual combustion of each cylinder ( ER _n , n = 1, 2, 3...) _{can be the difference value (ER B} -ER _n ), and the deviation (Δλ) of the lambda value of each cylinder is calculated during normal combustion of each cylinder. It may be _{a difference value (λ B -λ n} ) between the basic lambda value (λ _B ) and the lambda value (λ _n , n = 1, 2, 3...) calculated during actual combustion of each cylinder. Here, the basic engine speed roughness ER _B and the basic lambda value λ _B may be calculated based on a vehicle speed, an engine load, an engine RPM, and a measured value of an oxygen sensor.

Referring to FIG. 2, the logic for diagnosing the failure of each cylinder by the diagnosis unit 10 will be described in detail. The diagnosis unit 10 is injected from the injector 25 of each cylinder to diagnose the deviation of each cylinder. The amount of fuel is reduced, and when the amount of fuel is reduced, the deviation ΔER of the roughness of the engine speed of each cylinder and the deviation Δλ of the lambda value of each cylinder are calculated.

After that, the amount of fuel injected from the injector 25 of each cylinder is reduced until the deviation (ΔER) of the engine speed roughness of each cylinder reaches the set value (T), and lambda when such a fuel amount is reduced. It may be configured to determine the normal combustion or abnormal combustion of each cylinder by comparing the deviation of the value (Δλ) with the reference value (S). Here, the set value T is a set value for setting a reduction range of the amount of fuel for diagnosing a failure of each cylinder, and may be calculated through a map or table mapped according to vehicle specifications and driving conditions. For example, the set value T may be about 1.5. And, the reference value (S) is a reference value for diagnosing the failure of each cylinder by determining normal combustion or abnormal combustion of each cylinder, and this reference value (S) is through a map or table mapped according to the engine load and engine RPM. Can be calculated. For example, the reference value S may correspond to a deviation of the lambda value of about 10% to 15%.

As described above, when the fuel amount is decreased until the deviation ΔER of the engine speed roughness of each cylinder reaches the set value T, the deviation Δλ of the lambda value increases. As shown in Fig. 2, in the case of normal combustion, the lambda value (λ) may be 1 (λ=1) or close thereto, and in the case of abnormal combustion such as lean combustion, the lambda value (λ) becomes greater than 1. Can be (λ>1).

For example, while reducing the amount of fuel until the deviation (△ER) of the engine speed roughness of one cylinder reaches the set value (T), the deviation (△λ) of the lambda value of the cylinder is equal to or greater than the reference value (S). When this occurs (△λ≥S), the amount of fuel injected from the cylinder can be stably reduced during the time when the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T), so the cylinder is normal. Combustion may be possible (refer to arrow NC in FIG. 2), and thus the diagnosis unit 10 may determine the cylinder as normal combustion.

For example, while reducing the amount of fuel until the deviation (△ER) of the engine speed roughness of one cylinder reaches the set value (T), the deviation (△λ) of the lambda value of the cylinder is less than the reference value (S). If it is low (△λ<S), the amount of fuel injected from the cylinder rapidly decreases during the time when the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T), so the cylinder is lean. It may be an abnormal combustion condition such as combustion (refer to arrow AC in FIG. 2), and the diagnosis unit 10 can diagnose the cylinder as a fault condition by determining the cylinder as abnormal combustion, and the diagnosis unit 10 Stores the deviation (△λ) of the lambda value corresponding to the fault code of the corresponding cylinder (e.g., lean combustion, etc.) in the memory of the control unit 20, through which the cylinder deviation of the multi-cylinder internal combustion engine can be precisely monitored. have.

In this way, when the diagnostic unit 10 stores the deviation (Δλ) of the lambda value of the cylinder diagnosed as a failure in the memory of the control unit 20, the processor of the control unit 20 By substituting Δλ) into a map or an empirical formula, the corrected fuel amount (C _n , n = 1, 2, 3...) capable of correcting the amount of fuel injected from the injector 25 can be calculated.

In addition, the control unit 20 may adjust the amount of fuel injected into the cylinder by the injector 25 according to the _{calculated corrected fuel amount (C n, n = 1, 2, 3...).} For example, the control unit 20 includes the current fuel amount (I _n , n = 1, 2, 3...) and the corrected fuel amount (C _n , n = 1, 2, 3.) that the injector 25 is currently injected into the corresponding cylinder. Normal combustion of the cylinder can be performed by controlling to inject the fuel amount (I = I _n + C _{n) that is the sum of ..).}

In this way, when the failure code (eg, lean combustion, etc.) of each cylinder is stored in the memory of the control unit 20, the control unit 20 controls the injector 25 according to the stored failure code to perform normal combustion of the corresponding cylinder. can do.

Meanwhile, when the diagnosis unit 10 sequentially diagnoses a plurality of cylinders, the control unit 20 controls to increase the amount of fuel in the remaining cylinders when it is diagnosed as a failure (Δλ<S) of at least one cylinder. Through this, it is possible to control the total amount of fuel so that the average lambda value (λ _m ) for a plurality of cylinders reaches normal combustion (λ _{m = 1).}

For example, as shown in Fig. 3, in the case of a failure of cylinder 1 in a four-cylinder internal combustion engine, the remaining cylinders, that is, cylinders 2 (2cyl), and 3 are in accordance with the deviation (Δλ) of the lambda value of cylinder 1 (1cyl). Increase the fuel quantity of the cylinders (3cyl) and 4th cylinders (4cyl) so that the average lambda value (λ _m ) for the plurality of cylinders reaches the normal combustion state (λ _m = 1) You can control the amount of fuel for multiple cylinders.

In short, in the present invention, the deviation (Δλ) of the lambda value of the cylinder diagnosed as a fault condition by the diagnosis unit 10 is stored in the memory of the control unit 20, and the processor of the control unit 20 stores the deviation of the stored lambda value. By using (Δλ), it is possible to effectively control the injection of the amount of fuel by the injector 25 of the cylinder.

As described above, the present invention diagnoses the failure of each cylinder by diagnosing the failure of each cylinder using the deviation (△ER) of the engine speed roughness of each cylinder and the deviation (△λ) of the lambda value of each cylinder. In addition to being able to drastically reduce the time, there is an advantage in that the fuel amount deviation of each cylinder can be drastically reduced by controlling the fuel amount injection of each cylinder using the deviation of the lambda value.

In addition, the present invention has the advantage of being able to precisely monitor the deviation of each cylinder of a multi-cylinder internal combustion engine through diagnosis of a failure of the corresponding cylinder and adjustment of the injection amount of the injector 25.

Figure 4 is another aspect of the present invention shows a cylinder deviation monitoring method of a multi-cylinder internal combustion engine for monitoring the deviation of each cylinder of a multi-cylinder internal combustion engine having a plurality of cylinders.

Vehicle information (vehicle speed, etc.), engine information (engine load, engine RPM, etc.) by the control unit 20, the crank angle sensor 11, the oxygen sensor 12, and the exhaust valve 13 in the diagnosis unit 10 , Input the measured value of the oxygen sensor, etc. (S1).

The diagnosis unit 10 determines whether to diagnose the deviation of each cylinder based on vehicle information, engine information, and measured values of oxygen sensors (S2). Here, the diagnosis unit 10 diagnoses the deviation of each cylinder when the engine speed, engine load, engine RPM, and measured values of the oxygen sensor are out of the normal range. In addition, the diagnosis unit 10 does not diagnose the deviation of each cylinder when the engine speed, output, torque, etc. are within the normal range.

In this case, the diagnosis unit 10 may diagnose each cylinder individually or simultaneously. For example, after the diagnosis unit 10 diagnoses cylinder 1, it may sequentially diagnose cylinders 2, 3, etc., or individually, regardless of the order of cylinders, and diagnose all cylinders at the same time. May be.

And, if it is determined by the diagnosis unit 10 to diagnose the deviation of each cylinder, the diagnosis unit 10 is the vehicle speed, engine load, engine RPM, measured values of the oxygen sensor under the normal combustion condition of the cylinder to be diagnosed. The basic engine speed roughness ER _B and the basic lambda value λ _B are calculated using the same (S3).

Then, the control unit 20 reduces the amount of fuel injected from the injector 25 of the cylinder to be diagnosed (S4). When the amount of fuel is reduced, the diagnostic unit 10 includes the engine speed roughness (ER _n , n=1, 2, 3...) of each cylinder calculated from the crank angle sensor 11, and the oxygen sensor 12. _{) And the lambda values (λ n} , n = 1, 2, 3...) of each cylinder calculated by the exhaust valve 13 may be input.

After that, the diagnosis unit 10 calculates the deviation ΔER of the engine speed roughness of the cylinder and the deviation Δλ of the lambda value of the cylinder in real time (S5).

Here, the deviation (△ER) of the engine speed roughness of each cylinder is the basic engine speed roughness (ER _B ) calculated during normal combustion and the engine speed roughness (ER) calculated during actual combustion of each cylinder. _{It may be a difference value (ER B} -ER _n ) between n, n = 1, 2, 3...), and the deviation (Δλ) of the lambda value of each cylinder is a basic lambda value calculated during normal combustion ( It may be _{a difference value (λ B -λ n ) between λ B} ) and a lambda value (λ _n , n = 1, 2, 3...) calculated during actual combustion of each cylinder.

Then, the control unit 20 decreases the fuel amount of the cylinder until the deviation (ΔER) of the roughness of the engine rotation speed of the corresponding cylinder reaches the set value T (ΔER=T) (S6). Here, the set value T is a set value for setting a reduction range of the amount of fuel for diagnosing a failure of each cylinder, and may be calculated through a map or table mapped according to vehicle specifications and driving conditions. For example, the set value T may be about 1.5.

When the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T) (△ER=T), whether the deviation (△λ) of the lambda value of the cylinder is lower than the reference value (S) (△ λ<S) is determined (S7). Here, the reference value S is a reference value for diagnosing normal combustion or abnormal combustion of each cylinder, and the reference value S may be calculated from a map or table mapped according to engine load and engine RPM. For example, the reference value S may correspond to a deviation of the lambda value of about 10% to 15%.

As described above, when the fuel amount is decreased until the deviation ΔER of the engine speed roughness of the cylinder reaches the set value T, the deviation Δλ of the lambda value increases. As shown in Fig. 2, in the case of normal combustion, the lambda value (λ) may be 1 (λ=1) or close thereto, and in the case of abnormal combustion such as lean combustion, the lambda value (λ) becomes greater than 1. Can be (λ>1).

For example, if the deviation (△λ) of the lambda value exceeds the reference value (S) until the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T) (△λ≥S), the corresponding Since the amount of fuel injected from the cylinder is stably decreased during the time when the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T), the cylinder can be normal combustion (arrow in Fig.2). NC), thus, the diagnosis unit 10 may determine the cylinder as normal combustion and terminate the control logic.

For example, if the deviation (△λ) of the lambda value is lower than the reference value (S) until the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T), the corresponding Since the amount of fuel injected from the cylinder rapidly decreases during the time when the deviation (△ER) of the engine speed roughness of the cylinder reaches the set value (T), the cylinder may become abnormal combustion such as lean combustion ( 2), the diagnosis unit 10 may diagnose the cylinder as a failure by determining the cylinder as an abnormal combustion state.

After that, the diagnosis unit 10 stores the deviation (Δλ) of the lambda value of the cylinder diagnosed as a failure in the memory of the control unit 20 in the form of a failure code (S8). Here, the diagnostic unit 10 stores the deviation (Δλ) of the lambda value corresponding to the failure code (eg, lean combustion, etc.) of the corresponding cylinder in the memory of the control unit 20, through which each of the multi-cylinder internal combustion engines The cylinder deviation can be precisely monitored.

A processor (processor) of the control unit 20 assigns the deviation (△ λ) of the lambda value of the cylinder to the map or the empirical formula to correct the amount of fuel capable of correcting the amount of fuel injected by the corresponding cylinder injector (25) (C _n ) Is calculated (S9).

In addition, the control unit 20 may adjust the amount of fuel injected by the injector 25 of the cylinder according to the _{calculated corrected fuel amount (C n, n = 1, 2, 3...).} For example, the control unit 20 includes the current fuel amount (I _n , n = 1, 2, 3...) and the corrected fuel amount (C _n , n = 1, 2, 3.. .) By controlling to inject the total amount of fuel (I = I _n + C _n ), normal combustion of the cylinder can be performed. In this way, when the failure code (eg, lean combustion, etc.) of each cylinder is stored in the memory of the control unit 20, the control unit 20 controls the amount of fuel injected from the injector 25 according to the stored failure code. Normal combustion can be performed.

On the other hand, when the diagnosis unit 10 diagnoses a plurality of cylinders individually and sequentially, the control unit 20 increases the amount of fuel in the remaining cylinders when it is diagnosed as a failure (Δλ<S) of at least one cylinder. It can be controlled so that the average lambda value (λ _m ) for a plurality of cylinders reaches normal combustion (λ _m = 1) through this, it is possible to control the overall fuel amount.

For example, as shown in Fig. 3, in the case of a failure of cylinder 1 in a four-cylinder internal combustion engine, the remaining cylinders, that is, cylinders 2 (2cyl), and 3 are in accordance with the deviation (Δλ) of the lambda value of cylinder 1 (1cyl). It is possible to control the amount of fuel for the plurality of cylinders so that the average lambda value (λ _m ) for the plurality of cylinders reaches the normal combustion state (λ _m = 1) by increasing the fuel amount of the cylinders (3cyl) and 4th cylinders (4cyl). I can.

As described above, specific embodiments of the present invention have been described, but the present invention is not limited by the embodiments disclosed in this specification and the accompanying drawings, and may be variously modified by those skilled in the art within the scope not departing from the technical spirit of the present invention. .

10: diagnostic unit 11: crank angle sensor
12: oxygen sensor 13: exhaust valve
20: control unit 25: injector

Claims (15)

A diagnostic unit for diagnosing a failure of each cylinder by monitoring the deviation of each cylinder using an ENGINE SPEED ROUGHNESS and a lambda value; And
And a control unit that transmits vehicle and engine information to the diagnosis unit and controls ignition of each cylinder according to a deviation of each cylinder diagnosed by the diagnosis unit,
The diagnosis unit calculates the deviation of the engine speed roughness of each cylinder and the deviation of the lambda value of each cylinder through the engine speed roughness of each cylinder and the lambda value of each cylinder,
The diagnostic unit reduces the amount of fuel injected from the injectors of each cylinder until the deviation of the engine speed roughness of each cylinder reaches a set value, compares the deviation of the lambda value of each cylinder with a reference value, and compares the normal combustion of each cylinder or A cylinder deviation monitoring device of a multi-cylinder internal combustion engine that diagnoses the failure of each cylinder by determining abnormal combustion. The method according to claim 1,
A crank angle sensor and an oxygen sensor are connected to the diagnosis unit,
The diagnostic unit receives the engine speed roughness of each cylinder calculated by the crank angle sensor and a lambda value of each cylinder calculated by the oxygen sensor,
The diagnostic unit is a cylinder deviation monitoring device of a multi-cylinder internal combustion engine, configured to diagnose a failure of each cylinder by monitoring the deviation of each cylinder using the roughness of the engine speed of each cylinder and the lambda value of each cylinder.

delete The method according to claim 1,
The deviation of the engine speed roughness of each cylinder is a multi-cylinder internal combustion engine that is the difference between the basic engine speed roughness calculated during normal combustion of each cylinder and the engine speed roughness calculated during actual combustion of each cylinder. Cylinder deviation monitoring device. The method according to claim 1,
The deviation of the lambda value of each cylinder is the difference between the basic lambda value calculated during normal combustion of each cylinder and the lambda value calculated during actual combustion of each cylinder, a cylinder deviation monitoring device of a multi-cylinder internal combustion engine. The method according to claim 1,
The injector of each cylinder is connected to the control unit, and the cylinder deviation monitoring device of the multi-cylinder internal combustion engine controls the injector of each cylinder according to the information monitored by the diagnosis unit.

delete The method according to claim 1,
When reducing the amount of fuel until the deviation of the engine speed roughness of any one cylinder reaches the determined value, if the deviation of the lambda value of the corresponding cylinder is lower than the reference value, the corresponding cylinder is determined as an abnormal combustion state. A cylinder deviation monitoring device of a multi-cylinder internal combustion engine that diagnoses the cylinder as a failure. The method of claim 8,
The control unit calculates a corrected fuel amount for the cylinder by using the deviation of the lambda value of the cylinder diagnosed as a failure,
The control unit is a cylinder deviation monitoring device of a multi-cylinder internal combustion engine that controls the amount of fuel injected from the injector of the corresponding cylinder by using the corrected fuel amount. This is a method for monitoring the deviation of the cylinders of the multi-cylinder internal combustion engine.
If it is determined that the deviation of each cylinder is diagnosed through the vehicle information, the engine information, and the measured value of the oxygen sensor, the basic engine speed roughness and the basic lambda value of each cylinder are calculated.
Reduces the amount of fuel injected from the injector of the cylinder to be diagnosed,
Calculate the deviation of the engine speed roughness of the cylinder and the deviation of the lambda value of the cylinder,
If the fuel amount of the cylinder is decreased until the deviation of the engine speed roughness of the cylinder reaches the set value, the deviation of the cylinder is compared with the reference value to monitor the deviation of the cylinder and diagnose the failure of the cylinder. A method for monitoring cylinder deviation of a multi-cylinder internal combustion engine. The method of claim 10,
A method for monitoring the cylinder deviation of a multi-cylinder internal combustion engine that calculates the deviation of the engine speed roughness of the cylinder and the deviation of the lambda value of each cylinder through the engine speed roughness of each cylinder and the lambda value of each cylinder. The method of claim 11,
The deviation of the engine speed roughness of each cylinder is a multi-cylinder internal combustion engine that is the difference between the basic engine speed roughness calculated during normal combustion of each cylinder and the engine speed roughness calculated during actual combustion of each cylinder. How to monitor cylinder deviation. The method of claim 11,
The deviation of the lambda value of each cylinder is the difference between the basic lambda value calculated during normal combustion of each cylinder and the lambda value calculated during actual combustion of each cylinder, a method for monitoring the cylinder deviation of a multi-cylinder internal combustion engine. The method of claim 10,
The cylinder deviation monitoring method of a multi-cylinder internal combustion engine that diagnoses the cylinder as a failure if the deviation of the lambda value of the cylinder is lower than the reference value. The method of claim 14,
Using the deviation of the lambda value of the cylinder diagnosed as a failure, the corrected fuel amount for the cylinder is calculated,
A method for monitoring cylinder deviation of a multi-cylinder internal combustion engine that controls the amount of fuel injected from the injector of the corresponding cylinder using the corrected fuel amount.

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