KR20040040757A - Method of detecting misfire in a vehicle - Google Patents

Abstract

PURPOSE: A misfiring detection method of a vehicle is provided to secure convenience for drivers by informing the repairing time by early finding the misfiring and to prevent a 3-way catalyst converter from being broken down by the misfiring. CONSTITUTION: A misfiring detection method of a vehicle is composed of steps for sensing the amount of air and the instantaneous gradient of temperature in a cylinder through a MAP(Intake Manifold Absolute Pressure) sensor mounted to an engine in operating the engine of the vehicle(110,120); calculating the indication number of misfiring by using a neural network(130); deciding if the calculated indication number of misfiring is over a reference value(140); and warning the misfiring to the driver when the calculated indication number of misfiring is over the reference value(150).

Description

Misfire detection method of vehicle {METHOD OF DETECTING MISFIRE IN A VEHICLE}

The present invention relates to a misfire detection method of a vehicle, and more particularly, to a misfire detection method of a vehicle using an intelligent determiner.

As the exhaust regulations on engines are tightened, regulations on the system that inform the driver of engine abnormalities are being enacted. The importance of this system by On Board Diagnosis (OBD) means that even engines that are well-designed to meet existing regulations may not be able to burn fuel in the cylinders, ie spark plugs, fuel injectors. The driver should be informed of the phenomenon. Thus, misfiring detection plays a significant role in engine development and control.

However, at present, there is no misfire detection method by measuring the temperature in the cylinder, and the misfire state can be detected through the measurement of the combustion pressure, but there is a problem such that the combustion pressure sensor is required.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a misfire detection method of a vehicle that enables early detection of misfire and informing a driver of a maintenance time.

1A and 1B are schematic flowcharts sequentially showing a misfire detection method of a vehicle according to the present invention;

2 is a graph showing the temperature gradients in normal combustion and abnormal combustion.

3 is a diagram illustrating an intelligent determiner to which the present invention is applied.

4 is a signal diagram related to the present invention.

In the misfire detection method of a vehicle of the present invention for achieving the above object, (a) in the engine driving state of the vehicle, the step of sensing the amount of air and the instantaneous temperature change in the cylinder measured through the map sensor mounted on the engine Wow; (b) calculating the number of misfire indications using an intelligent determiner; (c) determining whether the number of misfire indications calculated in step (b) is greater than or equal to a reference value; and (d) alerting the driver of the misfire to the driver of the misfire if the misfire indication is greater than or equal to a reference value in the step (c).

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

1A and 1B are schematic flowcharts sequentially illustrating a misfire detection method of a vehicle according to the present invention.

Referring to the drawings, a misfire detection method of a vehicle according to the present invention is capable of more reliable control and detection in a driving area with an intelligent detector (neural network) as shown in FIG. 3 to be described below. In step S110, the amount of air measured through a MAP sensor mounted on the engine and an instantaneous gradient of temperature in the cylinder are sensed (steps 110 and 120).

In the step 120, the map sensor generates a constant voltage according to the temperature change in the cylinder combustion chamber of the engine, and measures the temperature by mounting it, and detects the presence or absence of the occurrence of combustion using the change rate of the temperature change caused by the combustion. do.

Subsequently, a true indication number is calculated using the intelligent determiner (step 130).

Then, it is determined whether the number of misfire indications calculated in step 130 is greater than or equal to the reference value (step 140).

In addition, when the condition at step 140 is not satisfied, that is, when the number of misfire indications is less than or equal to the reference value, the driver is alerted to the driver of the vehicle by, for example, an alarm (step 150).

On the other hand, the calculation of the number of misfire indications using the intelligent determiner in step 130, as shown in Figure 1b, first obtains the engine map and temperature data of the misfire condition in the normal operation state (step 131).

Subsequently, realization of the misfired state and the burned-out state causes the intelligent determiner to perform weighting learning to determine the weighting as a function of determining the misfired condition (step 133).

The intelligent determiner determines the weighting to indicate the number of misfire indications in the misfire condition and the combustion condition (step 135).

In addition, in step 150, the misfire warning to the driver is included in the ECU of the vehicle so as to be made using the misfire indication number.

The misfire detection method of the vehicle according to the present invention as described above will be described in more detail.

The spark ignition engine is ignited by fuel injected into the combustion chamber, and the engine is driven by the energy generated.

As shown in FIG. 2, ignition occurs in the engine and the temperature in the cylinder increases due to combustion, as shown in FIG. 2. After ignition, the temperature in the combustion chamber is greatly increased due to the rise of the temperature of the combustion gas, and thus the temperature change amount at this time is considered to be significantly different from the case of misfire.

Therefore, it is a thermostat that shows the temperature that changes after the ignition delay and the ignition delay, that is, the instantaneous gradient of approximately 20 degrees after the crank angle as an electrical voltage of about 800 to 2500 ° C in the combustion chamber in the cylinder. Temperature is measured by using a thermo couple sensor.

In the case of unburned gas, the temperature rise curve shows a very smooth curve, but in the case of burned gas, a sudden rise in temperature, which serves as a delta function, occurs. do. Therefore, the slope becomes very large.

Here, the reason for using the instantaneous change slope for the control may be that accurate measurement may not be possible due to the crank angle reference, sensor delay, and the like, and unburned fuel may be burned by late burning.

Therefore, the instantaneous change inclination determines the non-combustion by calculating the temperature measured within about 10 degrees of the crank angle and the temperature measured after 20 degrees in consideration of the combustion delay from the ignition time.

Herein, the temperature change is about 10 degrees based on the crank angle, and the temperature change at this time is a temperature change before and after combustion, and thus, there is a significant difference. In addition, in order to correct an error that may occur in misfire detection of the engine state, more accurate detection is possible through misfire detection, including measurement of air volume by a map sensor according to the load of the engine.

Referring to the control method on the basis of the above is as follows.

The two A point temperatures indicated in FIG. 2 are measured, and the temperature change rate according to the temperature change ΔT and the crank angle of the two points is obtained by Equation 1 below.

However, the temperature measurement point at the time of misfire is calculated | required by following formula (2).

The value obtained by Equation 1 above is the slope A of the straight line shown in FIG. 2, and the value obtained by Equation 2 is the straight line slope B.

The value of the slope thus obtained is defined as the temperature instantaneous change amount described above. This value is more different with higher load on the engine and faster speed.

However, when the fuel amount is extremely small under no load conditions such as idle conditions, the above two values may not have a large difference. Accordingly, the misfire condition is more stably determined by selecting the value of the intake manifold absolute pressure (MAP) for determining the load of the engine as another misfire condition detection element. That is, it is a control method of notifying whether misfire has occurred through two inputs.

An intelligent determiner as shown in FIG. 3 is used to detect misfire. This intelligent judge determines the weighting number, which is a function of judging the misfire condition by learning, by artificially realizing the misfire state and the firing condition through testing in the development stage. The misfire state can be determined by a kind of mapping. If this is expressed as a formula, it is as follows.

Input: {x} _ {1}, {x} _ {2}, output: z, z target (d): true case → 1

→ 0 if no misfire

{y} _ {1} = {f} _ {1} ({x} _ {1}, {x} _ {2}, {w} _ {11}, {w} _ {12}) = { x} _ {1} {w} _ {11} + {x} _ {2} {w} _ {12}

：

{y} _ {5} = {f} _ {5} ({x} _ {1}, {x} _ {2}, {w} _ {51}, {w} _ {52}) = { x} _ {1} {w} _ {51} + {x} _ {2} {w} _ {52}

z = {y} _ {1} {u} _ {1} + {y} _ {2} {u} _ {2} + {y} _ {31} {u} _ {3} + {y} _ {4} {u} _ {4} + {y} _ {5} {u} _ {5}

Error:

(D = 1 when misfire occurs, d = 0 when not occurring)

In the iteration, the weights w and u change as follows.

here,

Calculated by 0 <η <1.

Where the error E comes in under the right conditions, roughly the smallest value, i.e. U = {{u} _ {1}, {u} _ {2}, {u} _ {3}, {u } _ {4}, {u} _ {5}} and U = {{w} _ {11}, {w} _ {12}, ‥‥, {w} _ {51}, {w} _ { 52}} can be used as a function.

The control by such an intelligent judge normalizes the value of air from the map sensor mounted on the engine and the instantaneous temperature change in the cylinder to the physical quantity we need without changing the sensor value as it is (0 ~ 1). To determine the weighting indication under normal and firing conditions.

In the normal condition, data may be used for each operating area of the engine, and in the case of an abnormal condition, that is, a misfire, artificially generated data is used. (D = 1)

This is the case where the fuel is normally injected and does not occur because no ignition signal is given, and when the fuel is not injected because the ignition signal is given and a connector is not connected to the injector.

Here, the misfire condition is determined by making the Z value smaller than zero in the misfire condition and larger than zero in the normal condition. The misfire condition occurs occasionally even during normal engine operation, so the driver is advised to notify the driver when this number is repeated frequently. The description is as shown in FIG.

According to the engine cycle, misfire situation detection is applied, and when such misfires occur continuously or occur in a constant state and exceed a certain number of times, a warning message is sent to the driver.

By giving data to the above conditions for each condition, the weighting instruction is learned so that the number of misfire indications is, for example, more than 0.7 in the normal state, and 0.5 or less when misfire occurs. The weighting and intelligent judgment thus determined can be included in the ECU to inform the driver whether or not a misfire has occurred using the misfire indication.

The warning of misfire can be informed to the driver using an engine check in the vehicle to prevent air pollution and failure of the 3-way catalyst converter due to engine failure.

As described above, the misfire detection method for a vehicle according to the present invention has the following effects.

By finding misfires and notifying the driver when performance is reduced, appropriate measures can be taken to improve performance and identify exhaust problems.

In addition, it is possible to detect misfires early and inform maintenance points, thus providing convenience to the driver and preventing failure of the three-way catalytic converter due to misfires.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (3)

(a) sensing the amount of air measured by the map sensor mounted on the engine and the instantaneous temperature change in the cylinder in the engine driving state of the vehicle; (b) calculating the number of misfire indications using an intelligent determiner; (c) determining whether the number of misfire indications calculated in step (b) is greater than or equal to a reference value; and (d) alerting the driver to the driver of the vehicle when the number of misfire indications is greater than or equal to a reference value in the step (c). The method of claim 1, In the step (c), the calculation of the misfire indication by using the intelligent determiner, (e) obtaining engine map and temperature data of misfire conditions in a normal operation state; (f) performing weighting learning for realizing a misfired state and a combustion state to determine the number of weights, which is a function of determining the misfire condition of the intelligent determiner; (g) determining weighting by the intelligent determiner to indicate the number of misfire indications in misfire conditions and combustion conditions. The method of claim 1, In step (d) the warning of misfire to the driver, And including the intelligent determiner in the ECU of the vehicle so as to be made using the misfire indication number.