KR101562194B1

KR101562194B1 - Method for diagnosing obstacle of thermostat

Info

Publication number: KR101562194B1
Application number: KR1020090010651A
Authority: KR
Inventors: 함흥식
Original assignee: 콘티넨탈 오토모티브 시스템 주식회사
Priority date: 2009-02-10
Filing date: 2009-02-10
Publication date: 2015-10-21
Also published as: KR20100091457A

Abstract

The present invention discloses a method for diagnosing faults in a water temperature controller. A method for diagnosing a fault of a water temperature controller according to the present invention is a method for diagnosing faults in a water temperature controller, which calculates a difference value between a cooling water temperature of a radiator and a cooling water temperature of an engine when a predetermined first fault diagnosis condition is satisfied after starting an engine, And if it is diagnosed as a normal operation in the first trouble diagnosis step, if the cooling water temperature of the engine reaches the preset valve opening temperature, the cooling water temperature of the radiator And a second failure diagnosis step for re-diagnosing the failure of the water temperature controller based on whether the water temperature limit value is equal to or higher than a predetermined water temperature limit value. Accordingly, the present invention is intended to diagnose whether or not a water temperature controller that maintains the temperature of the cooling water in the engine is faulty and to guide the driver to the fault if an abnormality occurs. Particularly, in a specific mode such as an exhaust gas measurement mode, It is possible to diagnose whether the regulator is malfunctioning or not.

Water temperature controller

Description

METHOD FOR DIAGNOSING OBSTACLE OF THERMOSTAT FIELD OF THE INVENTION [0001]

The present invention relates to a method for diagnosing a fault in a water temperature controller, and more particularly, to diagnosing a fault in a water temperature controller that maintains a temperature of a cooling water constant in an engine, And more particularly, to a fault diagnosis method for a water temperature controller capable of diagnosing whether a water temperature controller fails even in a specific mode such as an exhaust gas measurement mode.

The cooling system is used as a means to prevent overheating of the engine and to protect the engine by keeping the engine at a proper temperature and to improve the combustion efficiency.

The combustion gas temperature in the cylinder reaches about 2000 degrees, but a considerable amount of this heat is absorbed into the cylinder, the cylinder head, the piston and so on. If the temperature of these parts excessively increases, the cylinder will be deformed or the oil film on the cylinder wall will be destroyed, resulting in poor lubrication and, in severe cases, damaging the engine.

Further, the combustion state is deteriorated to cause knocking or premature ignition, which is a factor for lowering the output of the engine. On the other hand, if it is cooled too much, the amount of loss due to cooling from the combustion caused by the combustion is reduced, thereby decreasing the thermal efficiency of the engine and increasing the fuel consumption.

The cooling method of the engine includes an air-cooling type in which the outside of the engine is directly cooled using outside air, and a water-cooling type in which cooling water is cooled to the inside of the engine.

In the water-cooled type, the cooling water is drawn into the cylinder block and the water jacket of the cylinder head to circulate the cooling water, so that the heat exchange is performed. The warmed cooling water is sent to the radiator and the water is circulated by the water pump .

In this water-cooled engine, the water pump circulates the cooling water, but the water temperature controller is installed in the cooling system to prevent the cooling water flowing to the cylinder from flowing to the radiator side when the temperature of the cooling water does not reach a certain temperature.

Furthermore, in the past, the water temperature controller has been diagnosed by the phenomenon that the difference between the actual cooling water temperature and the modeled cooling water temperature occurs by using the cooling water temperature modeling to diagnose the failure of the water temperature controller.

However, there are many variables (for example, running wind, engine heating amount, etc.) in the process of cooling water on modeling, and thus there is a limit to accurately modeling.

Because of this, there was always the possibility of a false diagnosis of the water temperature controller (that is, a false product is mistaken for a faulty product). In particular, by strengthening the regulations of the self-diagnosis of the vehicle, it is required to diagnose faults in a specific mode (for example, exhaust gas measurement mode), so that the coolant temperature modeling should be maintained close to the actual coolant temperature. There is a problem that diagnosis possibility becomes higher.

A solution is needed.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a water temperature controller that diagnoses whether a water temperature controller that maintains a temperature of cooling water in an engine is constant, And in particular, to provide a fault diagnosis method for a water temperature controller capable of diagnosing whether a water temperature controller fails even in a specific mode such as an exhaust gas measurement mode.

According to an aspect of the present invention, there is provided a method for diagnosing a fault in a water temperature controller, the method comprising: detecting a difference between a coolant temperature of the radiator and a coolant temperature of the engine, A first fault diagnosis step for diagnosing a fault of the water temperature controller according to whether the difference value is equal to or greater than a preset normal discrimination value and a second fault diagnosis step for diagnosing a fault in the water temperature controller, And diagnosing a fault of the water temperature controller based on whether the cooling water temperature of the radiator is equal to or higher than a predetermined water temperature threshold value when the temperature reaches a preset valve opening temperature.

Preferably, the first failure diagnosis condition is a condition including whether or not an elapsed time after startup of the engine reaches a predetermined reference time and whether or not the coolant temperature of the engine reaches a predetermined diagnostic execution temperature .

Preferably, the first failure diagnosis step is performed on the basis that the control valve of the water temperature controller is in a closed state.

Preferably, the first failure diagnosis step diagnoses that the water temperature controller is malfunctioning when the difference value is not equal to or greater than the normal determination value.

Preferably, the second failure diagnosis step includes determining whether or not the fuel injection prohibition time after the start of the engine reaches a preset limit value of the fuel injection prohibition time, and determining whether the engine idle time after the engine is started, When the second failure diagnosis condition including the determination as to whether or not the water temperature reaches the limit value of the ideal time is satisfied, does not perform the second diagnosis for determining whether the water temperature controller is faulty.

Therefore, in the present invention, it is intended to diagnose whether or not the water temperature regulator which maintains the temperature of the cooling water constantly in the engine is faulty and, if an abnormality occurs, inform the driver of the fault. Particularly, There is an advantage that the controller can be diagnosed as faulty.

Hereinafter, a preferred embodiment of a fault diagnosis apparatus for a water temperature controller 200 according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a fault diagnosis apparatus of a water temperature controller 200 according to an embodiment of the present invention. 1, the fault diagnosis device of the water temperature controller 200 includes a water temperature controller 200 for keeping the cooling water at a proper temperature to prevent overheating of the engine and the engine, an opening (not shown) of the water temperature controller 200, The radiator 100 for circulating the cooling water supplied from the engine to a predetermined temperature and the cooling water temperature of the engine and the cooling water temperature of the radiator 100 are measured according to whether or not the water temperature controller 200 And an electronic control unit 300 for informing the driver of the presence or absence of a failure.

Here, the electronic control unit 300 determines whether or not the elapsed time after the start of the engine reaches a predetermined reference time (for example, within 2 to 4 minutes) and whether or not the cooling water temperature of the engine reaches the preset diagnostic execution temperature If it is determined that the first fault diagnosis condition is satisfied, then the process for determining whether the water temperature conditioner 200 is faulty or not is performed.

The first step of determining whether the water temperature controller 200 is faulty is to measure the difference between the cooling water temperature of the engine and the cooling water temperature of the radiator 100, To determine whether there is a failure.

Thereafter, a second step for determining whether or not the water temperature controller 200 is faulty again is performed. This is because if the water temperature controller 200 is not normally operated in the first step and it is not accurately determined whether the water temperature controller 200 is malfunctioning (For example, about -12 degrees) of the cooling water warmer temperature controller 200 of the engine when the cooling water temperature of the radiator 100 is controlled to be lower than the opening temperature of the cooling water warmer temperature controller 200 of the engine, The water temperature controller 200 determines that the water temperature controller 200 has failed.

2 is an exemplary diagram showing a diagnosis result for the water temperature controller 200 shown in FIG. 2 (a) is a graph showing changes in cooling water temperature according to time and vehicle speed and cooling water temperature of the radiator 100 in the exhaust gas measurement mode in the case of the normal operation water temperature controller 200 In the case of a regular product, if the reference set value (for example, 2 to 4 minutes) after the engine start is reached, there is a difference between the actual cooling water temperature and the cooling water temperature of the radiator 100.

This is a phenomenon in which the water temperature controller 200 operates normally and the cooling water circulates inside the engine without circulating to the radiator 100 side. Therefore, if the difference between the cooling water temperature of the engine and the cooling water temperature of the radiator 100 is greater than a predetermined value, it can be determined that the water temperature controller 200 operates normally.

Since the water temperature controller 200 is opened in the case of the faulty water temperature controller 200, the rising speed of the actual cooling water temperature is lower than that of the normal product because the cooling water is circulated to the radiator 100 immediately after the start of operation. Coolant temperature of the radiator It indicates the temperature which is about or slightly lower than the coolant temperature of the engine.

Therefore, if the difference between the cooling water temperature of the engine and the cooling water temperature of the radiator 100 is within the set value for a predetermined time (e.g., about 2 to 4 minutes) after the engine is started, it is determined that the water temperature controller 200 is faulty.

3 is a flowchart showing an operation procedure of the fault diagnosis apparatus of the water temperature controller 200 shown in FIG. The fault diagnosis method of the water temperature controller (200) includes a first fault diagnosis for determining whether the elapsed time after engine startup has reached a preset reference time and whether the cooling water temperature of the engine reaches a predetermined diagnosis execution temperature The fault diagnosis of the first stage is executed (S1 to S5).

Thereafter, a difference value between the cooling water temperature of the radiator 100 and the cooling water temperature of the engine is calculated. If the calculated difference value does not correspond to the predetermined normal discrimination value, it is determined that the water temperature controller 200 malfunctions ( S7 and S9).

If it is determined in step S7 that the calculated difference value corresponds to the predetermined normal discrimination value, it is first determined that the water temperature controller 200 operates normally (S11), and the fuel injection prohibition time after the engine is started Whether or not the engine idle time after the start of the engine reaches a second threshold value which is a limit value of an engine idle time preset, (Step S13). In step S13, it is determined whether or not the water temperature controller 200 is to be diagnosed as faulty.

If the second failure diagnosis condition is satisfied in step S13, the operation condition of the vehicle deviates from the limit value for determining whether the water temperature controller 200 is faulty. In this case, the additional condition for the water temperature controller 200 And stops judging whether or not the failure has occurred.

Thereafter, when it is determined that the second failure diagnosis condition is not satisfied, it is determined whether the coolant temperature of the radiator 100 is equal to or higher than a preset water temperature limit value when the coolant temperature of the engine reaches the predetermined valve open temperature. If it is determined that the cooling water temperature of the radiator 100 is not higher than the predetermined water temperature threshold value, it is determined that the water temperature controller 200 does not operate normally (S15 to S21).

When the engine starts, the processing for determining whether the water temperature controller 200 is faulty is also ended (S23).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

Further, the present invention is intended to diagnose whether or not a water temperature controller that maintains the temperature of the cooling water in the engine is faulty and to guide the driver to the fault if an abnormality occurs. Particularly, in a specific mode such as an exhaust gas measurement mode, It is an invention that is industrially applicable because it is intended to diagnose whether or not the regulator is faulty, and is not only a possibility of commercialization or sales, but also a reality that can be practically performed.

1 is a configuration diagram of a fault diagnosis apparatus for a water temperature controller according to an embodiment of the present invention;

2 is an exemplary view showing a diagnosis result for the water temperature regulator shown in Fig. 1, and Fig.

3 is a flowchart showing the operation of the fault diagnosis apparatus of the water temperature controller shown in FIG.

Description of the Related Art

100: radiator 200: water temperature controller

300: Electronic control unit

Claims

A method for diagnosing a fault in a water temperature controller for switching the flow of cooling water to a radiator,

And a controller for calculating a difference value between the cooling water temperature of the radiator and the cooling water temperature of the engine if the predetermined first diagnosis condition is satisfied after starting the engine, A first fault diagnosis step for diagnosing a fault; And

And a second failure diagnosis step for re-diagnosing the failure of the water temperature controller based on the cooling water temperature of the engine and the cooling water temperature of the radiator when the water temperature controller is diagnosed as normal in the first failure diagnosis step,

The second failure diagnosis step

When the fuel injection prohibition time after the start of the engine reaches a predetermined limit value and the engine idle time after the start of the engine reaches a predetermined limit value, the controller does not diagnose the fault of the water temperature regulator again, And diagnoses the failure of the water temperature regulator only when the post fuel injection prohibition time does not reach the predetermined limit value or the engine idle time after the engine start does not reach the preset limit value Diagnostic method.

The method of claim 1, wherein the first fault diagnosis condition

Wherein the condition is a condition including whether or not an elapsed time after startup of the engine reaches a predetermined reference time and whether or not the cooling water temperature of the engine reaches a predetermined diagnostic execution temperature.

The method of claim 1, wherein the first fault diagnosis step

And the control valve of the water temperature controller is in a closed state.

4. The method of claim 3, wherein the first fault diagnosis step

And diagnosing that the water temperature controller is faulty if the difference value is not more than the predetermined value.

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