KR101836677B1 - Method for detecting crank angle of vehicle having multi point injection engine during cam position sensor failure - Google Patents

Abstract

The present invention is a method for detecting a crank angle at the time of a cam position sensor failure in a vehicle equipped with an MPi engine. A control method according to the present invention includes the steps of: determining whether a cam position sensor is faulty; Performing a double ignition simultaneously on all cylinders suspected of having a top dead center by using a signal of a crank position sensor when the cam position sensor fails; Selecting one of the cylinders suspected of being the top dead center after the completion of the start and attempting single ignition; And determining the crank angle according to the ignition result.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of detecting a crank angle in a vehicle equipped with an MPi engine,

The present invention relates to a method for detecting a crank angle at the time of a failure of a cam position sensor in a vehicle equipped with an MPi engine, and more particularly to a method for detecting a crank angle through a start- to be.

In the case of an automobile equipped with an internal combustion engine, the fuel injection timing and the ignition timing are controlled in accordance with the running conditions of the vehicle and the like. In particular, in the case of a multi-cylinder engine, it is necessary to precisely synchronize the fuel injection timing and ignition timing for each cylinder in order to suppress the generation of noxious gas due to output reduction or incomplete combustion.

In order to synchronize the engine, it is necessary to detect the crankshaft rotation position accurately for each cylinder. Patent Document 1 discloses a conventional technique for detecting an accurate rotational position of a crankshaft. In the conventional art as disclosed in Patent Document 1, a crank position sensor and a cam position sensor are utilized for accurate position detection of the crankshaft.

However, when a failure occurs in the cam position sensor, only the position of the piston in each cylinder can be known only by sensing information from the crank position sensor, and it can not be known which cylinder each cylinder is in. That is, it can be determined from which cylinder the piston is at the top dead center, but it can not be determined whether the cylinder in which the piston is located at the top dead center is in the compression stroke or in the exhaust stroke.

Therefore, when the cam position sensor fails, the accurate crank angle can not be known, so that the crank angle can not be determined at the time of starting.

Patent Document 1: Published Japanese Patent Application No. 2003-0029367 (Apr. 14, 2003)

How to deal with the failure of the cam position sensor may vary depending on the type of engine.

The MPi engine (Multi Point Injection) is an engine in which a fuel injection valve is provided for each cylinder, and fuel is injected in advance from each intake manifold. In the MPi engine, when it is difficult to detect an accurate crank angle due to a failure of the cam position sensor, a double ignition is performed by simultaneously igniting all the cylinders estimated to be located at the top dead center through the crank position sensor, You can either keep the start up or restart.

However, in this case, the accurate angle of the crank can not be grasped, and it is necessary to simultaneously ignite the plurality of cylinders in order to maintain the starting, and thus the durability of the ignition related parts sharply deteriorates.

On the other hand, the GDI engine (gasoline direct injection engine) is an engine that injects gasoline directly into a cylinder filled with air. In the GDI engine, the actual crank angle in each cylinder can be grasped through test injection into any one of the cylinders and whether or not the engine RPM is raised.

However, in such a method, several test injections need to be performed to find a suitable cylinder, which results in delayed start-up and fuel consumption. In addition, when the cylinder to which the test injection is performed is not a suitable cylinder, a situation such as misfiring occurs, and fuel is adsorbed in the cylinder at the time of cold running, or melts in the catalyst, have.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a control method capable of stably holding the start or hanging of the cam position sensor in a vehicle equipped with an MPi engine and detecting the crank angle in a short time And to provide the above-mentioned objects.

The present invention provides a method for detecting a crank angle at the time of a cam position sensor failure in a vehicle equipped with an MPi engine, the method comprising the steps of: determining whether a cam position sensor is faulty; Performing a double ignition simultaneously on all cylinders suspected of having a top dead center by using a signal of a crank position sensor when the cam position sensor fails; Selecting one of the cylinders suspected of being the top dead center after the completion of the start and attempting single ignition; And determining the crank angle according to the ignition result.

Preferably, the method further includes the step of determining whether or not any one of the fuel pump, the injector, and the ignition plug is faulty after completion of startup by the multi-cylinder ignition.

Preferably, in the step of determining the crank angle after completion of starting by the multiple cylinder ignition, the crank angle is determined by confirming whether or not the RPM of the engine is lowered at the time of ignition in the arbitrarily selected cylinder.

Preferably, the misfire determination using the engine roughness is held until the crank angle is determined by attempting to ignite the single cylinder by selecting any one of cylinders suspected of top dead center, and by determining the crank angle, After the engine becomes drivable by ignition, the misfire determination suspension is released.

Preferably, when RPM degradation of the engine occurs at the ignition of the arbitrarily selected cylinder, the crank angle at the point where the next missing tooth is detected in the signal received from the crank position sensor is 360 degrees offset Then, an arbitrary cylinder in the susceptible cylinder at the top dead center is selected based on the offset signal, and a single cylinder ignition is attempted.

Preferably, at 360 degree offsets of the crank angle, the number of single cylinder ignition attempts is counted.

Preferably, when the RPM reduction of the engine occurs at the time of ignition in the arbitrarily selected cylinder, when the number of single cylinder ignition attempts is equal to or more than the predetermined number of times, all cylinders of the top dead center are simultaneously ignited, .

Preferably, when it is determined that a failure has occurred in at least one of the fuel pump, the injector, and the spark plug, multiple cylinder ignition is simultaneously performed on all the cylinders suspected of having the top dead center, and the engine is driven.

In the present invention, compared to the control method in the GDi engine, there is no additional fuel consumption at startup, and the engine can be restarted within a short period of time through multi-cylinder ignition in which all cylinders suspected to be top dead center are ignited simultaneously in the MPi engine Do.

Since the temperature of the inner wall of the engine is considerably raised in the engine RPM in which the start-up is widened due to the multi-cylinder ignition, the problem of the fuel adsorption in the cylinder at the time of cold running in the control method of the GDi engine or the catalyst melt- Can be significantly mitigated.

Since the single cylinder is ignited after the startup is completed by the multiple cylinder ignition, the accurate crank angle can be detected. Thereafter, the engine can be continuously driven by the single cylinder ignition, It is possible to suppress the problem of deterioration of durability.

Also, in the case of a GDi engine that repeats test injection until it finds a cylinder suitable for ignition, the probability of finding a suitable cylinder in a single test injection is only 25%. If the ignition is performed on a single cylinder after the start-up is completed by the multi-cylinder ignition, the probability of finding a suitable cylinder by one ignition is 50%, and a cylinder suitable for ignition can be found with a high probability.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing the configuration of an embodiment of an engine synchronization apparatus to which a control method according to the present invention is applied; Fig.
2 is a flowchart showing a control method according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing an embodiment of an engine synchronization apparatus to which a control method of the present invention is applied. 1, the engine synchronizing apparatus according to the present invention includes a cam position sensor 100, a crank position sensor 200, and a control unit (ECU) 300.

The cam position sensor 100 senses a cam edge at the time of rotation of the camshaft of the intake cam and the exhaust cam and detects a cam edge position of the camshaft in the form of a pulse in which the voltage phase is inverted between the high level H and the low level L And outputs it to the control unit 200 as a cam signal. For example, when the output of the cam position sensor 100 is at the high level (H), the cam 110 is positioned above the line L1 indicated by the dotted line, and when the output of the cam position sensor 100 is at the low level L, When the cam 110 is positioned below the line L1. Here, the cam 110 is for opening and closing an intake valve and an exhaust valve provided in the combustion chamber, and the camshaft rotates in synchronization with the crankshaft.

The crank position sensor 200 is disposed in the vicinity of the sensor wheel 210 provided coaxially with the crankshaft. The sensor wheel 210 is provided with a plurality of teeth 220 along its outer periphery. The crank position sensor 200 detects the rotation of the crankshaft by sensing the tooth shape of the concavo-convex shape, and outputs the result as a crank signal in the form of a pulse to the control unit 300. At this time, the sensor wheel 210 is not formed with a tooth throughout the circumferential direction, but a part of the tooth is missing. The crank position sensor 200 recognizes the sensor wheel 210 as a missing tooth 230 do.

The control unit 300 receives the cam signal and the crank signal from the cam position sensor 100 and the crank position sensor 200 and determines the crank position and the cam position using the received result. Control of the fuel pump 400, the injector 500, and the spark plug 600 using the determined crank position and cam position information controls the synchronization of the fuel injection timing and the ignition timing for each cylinder of the engine do.

Since the cam 110 rotates at a constant speed, the signal output from the cam position sensor 100 is divided into low level (L) time and high level (H) time for a predetermined time. As described above, the camshaft rotates in synchronism with the crankshaft, and the camshaft makes one revolution when the crankshaft makes two revolutions. Therefore, it is set so that the missing of the crank signal is detected at a specific point in time between the low level and the high level of the cam signal.

Using the signals from the crank position sensor 200, the controller 300 can determine the positions of the pistons for the respective cylinders, and the signals from the crank position sensor 200 and the cam position sensor 100 are used So that the crank angle can be determined. That is, it is possible to accurately detect the position of the piston in each cylinder with respect to the position of the stroke.

In the engine synchronization apparatus, the control unit 300 can synchronize the engine using the detected crank angle. However, as described above, since the accurate crank angle can not be known when the cam position sensor fails, the crank angle can not be determined at startup.

Hereinafter, a control method according to the present invention for detecting an accurate crank angle when a failure occurs in the cam position sensor 100 will be described in more detail on the basis of the contents of FIG.

First, the ECU 300 determines whether a malfunction has occurred in the cam position sensor 100 (S100). Preferably, the failure of the cam position sensor 100 can be determined based on whether a signal is not received from the cam position sensor 100 or an abnormality occurs in the waveform of the received signal. Further, when the cam position sensor 100 fails, it is difficult to precisely determine the crank angle, so that it is difficult to precisely control the engine synchronization, and the engine drive mode is switched to the limphome mode.

If the cam position sensor 100 fails to receive a normal signal from the cam position sensor 100, the crank angle can not be accurately determined, and thus the cylinder suitable for ignition can not be determined, It is difficult to hang or keep. Thus, the ECU 300 uses the signal from the crank position sensor 200 to determine a cylinder suspected of the piston being located at the top dead center, and to ignite the ignition plug 600 (S110).

When ignition is performed on all of the top dead center cylinders, ignition is normally performed in the cylinders in the compression stroke of the cylinders in which ignition is performed, and startup is started.

Next, in this embodiment of the present invention, the ECU 300 determines whether startup has been normally performed (S300). If it is determined that startup has been performed, the ECU 300 determines whether any of the top dead center suspicious cylinders The ignition plug 600 is controlled so as to perform single cylinder ignition (S140).

Then, the ECU 300 detects a change in the engine RPM resulting from the single-cylinder ignition (S160).

In the case of a four-cylinder engine, one of the two cylinders in which the piston is located at the top dead center is in the compression stroke and the other in the exhaust stroke. Therefore, if the cylinder subjected to single cylinder ignition is a cylinder in the compression stroke suitable for ignition, the engine RPM is maintained without deterioration. Accordingly, the crank angle is directly fixed, and the engine synchronization is performed based on the determined crank angle (S170).

Conversely, if the cylinder subjected to the single cylinder ignition is a cylinder in the exhaust stroke which is not suitable for ignition, the RPM of the engine can not be maintained and is lowered. In this case, the ECU 300 offsets the crank angle by 360 degrees (S210), and the offset crank angle becomes the finalized crank angle, and the engine synchronization is performed based on the crank angle (S170).

Therefore, it is possible to accurately determine the crank angle by performing single cylinder ignition once after ignition of multiple cylinders for starting (S170). That is, it is possible to determine a cylinder suitable for ignition. In the case of a four-cylinder engine, in the case of a GDi engine, a maximum of four injections must be performed in order to determine a suitable cylinder. However, according to the control method of the MPi engine of the present invention, only one multi-cylinder ignition and one single ignition A suitable cylinder can be determined. Therefore, the crank angle can be determined with a high probability in a short time.

On the other hand, when the ECU 300 has offset the crank angle by 360 degrees in the previous step S210, the single cylinder ignition attempt count is counted (S220). The number of maximum ignition attempts is limited so that the engine is stably driven by performing multi-cylinder ignition more quickly when the engine RPM is lowered and the crank angle is not yet determined.

On the other hand, the number of single-cylinder ignition attempts is counted by the ECU 300 each time a single cylinder ignition is performed after startup through multi-cylinder ignition. The value is initialized each time the control method of the present invention is started. Preferably, the initialization of the previously stored number of times of single cylinder ignition at the start of startup through the multi-cylinder ignition proceeds.

When the crank angle is determined, the ECU 300 can continue the engine synchronization by single cylinder ignition based on the determined crank angle information (S170). Therefore, since it is not necessary to continuously maintain the ignition of the multiple cylinders in order to maintain the starting, the durability of the ignition system components can be further increased.

According to another preferred embodiment of the present invention, the ECU 300 determines whether or not the start by the multi-cylinder ignition has been completed (S120), and then determines whether the ignition plug 600 (Step S130).

The presence or absence of a failure of the relevant part can be grasped through diagnostic information using an ASIC (Application-Specific IC) provided in the system of the ECU that drives and controls the relevant components, for example.

If the above components fail, normal fuel supply, injection into the cylinder and ignition can not occur. In the present invention, the crank angle is determined by changing the engine RPM at the time of ignition of a single cylinder on the premise of the normal operation of the above-described components. When the upper component fails, the ignition is not switched from the multi- The multi-cylinder ignition is maintained to drive the engine (S190).

According to another preferred embodiment of the present invention, the ECU 300 suspends misfire determination (S180) while performing single cylinder ignition on any cylinder to find whether the engine RPM is lowered in order to find a physically suitable cylinder. The reason for suspending the misfire determination is that the change in the engine RPM is a type of engine roughness used in the misfire determination, and therefore, (Fail Mode) is arbitrarily applied to the combustion system (ignition, fuel, etc.) for discriminating the cylinders so as not to confuse the misfire judgment of the OBD (On-board Diagnostics) item.

The misfire determination of the engine can be determined using Engine Roughness. The term "engine roughness" refers to the amount of change in angular velocity for each 180 ° in the case of a four-cylinder, and is typically used for misfire diagnosis. In other words, in the case of misfire, the value of the engine roughness can be seen to be largely out of the cylinder where the misfiring has occurred. Therefore, when the wrong engine synchronization is performed, it is possible to determine whether the synchronization of the engine is correct based on the fact that the amount of change in the engine roughness value is different from the normal state.

According to another preferred embodiment of the present invention, when the maximum number of single cylinder injection attempts is equal to or greater than the predetermined value (S200), the fail safe mode is not performed, and all of the top dead center cylinders are ignited to drive the engine (S230).

In the case where the crank angle can not be determined even when a large number of single-cylinder ignition is performed, the engine RPM continues to be lowered, and therefore, normal running becomes difficult, so that the multiple cylinders are ignited to continue the engine.

According to the present invention as described above, when the cam position sensor fails, the ignition is simultaneously applied to the plurality of cylinders, so that the engine can be started or maintained at a rapid speed. As shown in FIG.

100: cam position sensor 110: cam
200: crank position sensor 210: sensor wheel
220: Tooth 230: Missing tooth
300: control unit (ECU) 400: fuel pump
500: Injector 600: Spark plug

Claims (8)

A method for detecting a crank angle at the time of a cam position sensor failure in a vehicle equipped with an MPi (Multi Position Injection) engine,
Determining whether the cam position sensor is faulty;
Performing a double ignition simultaneously on all cylinders suspected of having a top dead center by using a signal of a crank position sensor when the cam position sensor fails;
Selecting one of the cylinders suspected of having the top dead center after the completion of starting by the multiple cylinder ignition and attempting single ignition;
And determining a crank angle in accordance with the ignition result in the arbitrarily selected cylinder. The method of detecting a crank angle when a cam position sensor fails in a vehicle equipped with an MPi engine. The method according to claim 1,
Further comprising the step of determining whether or not any one of the fuel pump, the injector, and the ignition plug is faulty after completion of startup by the multi-cylinder ignition method. The crank angle detecting method in a vehicle equipped with an MPi engine . The method according to claim 1,
Wherein the step of determining the crank angle determines the crank angle by confirming whether or not the RPM of the engine is lowered at the time of ignition in the arbitrarily selected cylinder. Angle detection method. The method according to claim 1,
Wherein the misfire judgment using the engine roughness is suspended until the crank angle is determined by attempting to ignite any one of the cylinders suspected of having the top dead center and igniting the single cylinder,
Wherein the misfire judgment suspension is released after the engine is driven by the single cylinder ignition due to the determination of the crank angle. The method of claim 3,
When the RPM reduction of the engine occurs at the time of ignition in the arbitrarily selected cylinder,
A crank angle sensor for detecting a next missing tooth in a signal received from the crank position sensor is offset 360 degrees and an arbitrary cylinder in the top dead center cylinder is selected based on the offset signal, And the ignition is attempted when the cam position sensor fails in the vehicle equipped with the MPi engine. The method of claim 5,
Wherein the number of single cylinder ignition attempts is counted when 360 degrees of the crank angle is offset. The method according to claim 5 or 6,
When the RPM reduction of the engine occurs at the time of ignition in the arbitrarily selected cylinder,
Wherein when the number of times of the single cylinder ignition attempts is equal to or greater than a predetermined number, the multi-cylinder ignition is simultaneously performed on all of the top dead center cylinders to drive the engine. Angle detection method. The method of claim 2,
Characterized in that, when it is judged that a failure has occurred in at least one of the fuel pump, the injector and the spark plug, the engine is driven by performing simultaneous multi-cylinder ignition on all the cylinders suspected of having the top dead center A method of detecting a crank angle in the event of a cam position sensor failure.

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