KR20020058889A - Method for controlling water pump of a vehicle - Google Patents

Abstract

PURPOSE: A water pump of engine is turned off in an ignition to reduce THC(Tetrahydrocannabinol) among an exhaust gas. CONSTITUTION: When a control unit confirms an engine start, it is decided whether a water temperature of cylinder block reaches a first critical value. If not, the control unit receives a stored catalyst temperature and compares it with a second critical value to decide operating a water pump of cooling system. If the water temperature reaches the critical value, the control unit receives the catalyst temperature and compares with a third critical value to decide operating the water pump.

Description

Water Pump Control Method for Vehicles {METHOD FOR CONTROLLING WATER PUMP OF A VEHICLE}

The present invention relates to a method of controlling a water pump of a vehicle, and more particularly, to a method of controlling a water pump of a vehicle for reducing the amount of THC (Tetrahydrocannabinol) in the exhaust gas by turning off the water pump of the engine under a predetermined condition when the vehicle is started. It is about.

In general, a vehicle equipped with an internal combustion engine is provided with cooling means for exchanging heat generated during operation of the engine. This cooling means enables the vehicle to perform proper heat exchange, prevents overheating of the engine and enables continuous output generation.

A schematic structure of a cooling system of an automobile including such cooling means is shown in FIG.

The cooling system of the automobile shown in Fig. 1 is forced to circulate the cooling water heated by the heat of combustion of the engine by the water pump 17 and passes it through the radiators 14 and 15 to release heat, and then back to the engine. Water-cooling type to circulate is adopted.

The water-cooled cooling system includes a thermocouple 13 to prevent cooling of the cooling water until the cooling water reaches a constant temperature at the start of the engine. Therefore, the thermocouple 13 is closed when the engine is started so that the coolant is circulated from the cylinder block 11 through the coolant passage 12 to the cylinder block 11 again so that the coolant temperature is at an appropriate water temperature. Subsequently, when the coolant temperature reaches a constant value by the engine operation, the thermocouple 13 is opened to cool the radiator tube 14 to which the fin 15 is attached from the cylinder block 11 via the coolant passage 12. The water is pumped back into the cylinder block 11 by the water pump 17.

At this time, the water pump 17 is fastened to the fleece 16 directly connected to the crankshaft and the belt is driven at the same time as the engine starts to force the circulation of the coolant, it is not controlled by the electronic control means such as ECU.

However, in the related art described above, since the water pump 17 is driven and connected to the crankshaft only for the purpose of forced circulation of the cooling water, there is a problem that the engine is overcooled and the THC content in the exhaust gas is increased.

In addition, the water pump on / off control technology for the purpose of improving fuel economy has a disadvantage in that the ratio of the driving resistance of the water pump to the running resistance at the time of actual running is small and the THC reduction effect is minute.

Therefore, in view of the recent tightening of regulations on the exhaust gas of internal combustion engines, a technical means for reducing the THC content of the exhaust gas by appropriately controlling the cooling process of the engine by the cooling system is required.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to provide a vehicle for reducing the amount of THC in the exhaust gas by turning off the water pump of the engine under certain conditions at the start of the vehicle. To provide a water pump control method.

1 is a schematic configuration diagram of a cooling system of a typical vehicle.

2 is a signal processing flowchart of an ECU to which the present invention is applied.

Figure 3 is a flow chart of a water pump control method for a vehicle according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

11 cylinder block 12 coolant passage

13: thermocouple 14: radiator tube

15: pin 16: pulley

17: water pump 18: cooling fan

19: bypass valve

Water pump control method of a vehicle of the present invention for achieving the above object, the control unit for controlling the operating state of the engine by receiving a signal detected by the in-vehicle sensing means in a vehicle provided with a cooling system the detection Determining whether the engine temperature is reached through a detection signal of the means, determining whether the water temperature of the cylinder block reaches a set first threshold value; When the water temperature of the cylinder block falls below the set first threshold, the control unit is configured to determine whether to drive the water pump of the cooling system by applying a mapped catalyst temperature and comparing it with the set second threshold. Wow; If the water temperature of the cylinder block does not fall below the set threshold, the control unit is configured to determine whether to drive the water pump of the cooling system by applying the catalyst temperature and comparing it with the set third threshold; When the driving conditions of the water pump is established, the control unit is characterized in that it comprises the step of driving the water pump by applying a control signal to the actuator.

According to the above configuration, the present invention prevents the driving of the water pump when the temperature of the cylinder block at the start of the engine falls below the first threshold, when the catalyst temperature to which the control unit is mapped is below the second threshold. Then, the control unit maintains the driving prevention state of the water pump until the first release condition set for driving the water pump is satisfied.

In addition, the control means creates a temperature model and obtains the catalyst temperature and the exhaust gas temperature in each operating region in advance through the test of the engine, and stores them in the form of a map inside the engine. Fit

In addition, if the temperature of the cylinder block at the start of the engine is greater than or equal to the first threshold, the control unit prevents the water pump from driving when the mapped catalyst temperature is below the third threshold. Then, the control unit maintains the driving prevention state of the water pump until the second release condition set for driving the water pump is satisfied.

In this case, the second threshold value and the third threshold value are preferably set differently, and the first release condition and the second release condition may be set differently.

In the present invention, when the water pump is turned off at the initial start of the engine, the temperature difference of the cooling water temperature increases at a position where the transfer of the combustion heat generated in the combustion chamber is advantageous and a position which is advantageous, and the temperature of the cylinder wall close to the combustion chamber increases Rising faster than on-drive can reduce flame quenching, the main mechanism of hydrocarbon production. In addition, since the temperature of the cylinder head portion rises most rapidly, the temperature around the exhaust port becomes high, and the concentration of THC can be reduced by promoting the hydrocarbon reduction reaction in the exhaust gas.

Therefore, deterioration does not occur in the constituent materials of the engine, and a decrease in output does not occur due to excessive temperature rise of the cylinder and the intake manifold, and a condition in which the exhaust gas purification efficiency by the catalyst reaches a satisfactory condition is satisfied. By applying the present invention to maintain the off state of the water pump until the amount of THC is reduced.

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

In a preferred embodiment of the present invention, the control unit is implemented as an ECU (Electronic Control Unit).

A schematic signal processing flow diagram of such an ECU is shown in FIG.

In FIG. 2, the sensing means for detecting and applying various data in the vehicle to the ECU 26 includes a start switch 21 and cooling water temperature sensors 22 and 23 provided in the cylinder block and the cylinder head, respectively.

When the water pump 28 is driven at the same time as the engine is started, the cooling water temperature distribution inside the engine is uniformly increased. However, if the water pump 28 is not driven even after the engine is started, the amount of heat transfer from the combustion chamber varies depending on the position. Therefore, the temperature distribution in the cylinder head portion, the upper and lower parts of the cylinder block increases and shows a big difference. Therefore, when measuring only the temperature at the inlet or outlet of the radiator, it is impossible to accurately measure the temperature. Therefore, in the on / off control of the water pump 28, a cooling water temperature sensor for measuring the water temperature of the cylinder head portion that is most important ( 22) and a cooling water temperature sensor 23 for measuring the water temperature of the upper part of the cylinder block related to flame latching.

Therefore, the cooling water temperature sensor 22 of the cylinder block is mounted between combustion chamber 2 and combustion chamber 3, and the cooling water temperature sensor 23 of the cylinder head is preferably mounted at the thermocouple position directly under the combustion chamber.

In addition, the actuator 27 for switching between the on / off state of the water pump 28 in accordance with the control signal of the ECU 26 should be provided. The actuator 27 may be implemented as a motor that directly controls the driving of the water pump 28 or a solenoid valve that simply turns on / off the power transmitted from the crankshaft, and the type and control logic thereof are defined by the present invention. It is not limited.

In addition, the present exemplary embodiment sets the first threshold value, the second threshold value, the third threshold value, and the first release condition and the second release condition based on the 1.6 DOHC A / T vehicle.

3 is a flow chart according to an embodiment of the present invention.

According to FIG. 3, the ECU 26 checks whether the engine is started according to the signal of the in-vehicle start switch 21 (ST21).

Thus, upon confirming the start of the engine, the ECU 26 compares the cylinder block water temperature detected by the coolant temperature sensor 22 of the cylinder block with the set first threshold value. The first threshold is preferably set to a temperature index of 80 ° C (ST22).

When it is confirmed in step ST22 that the cylinder block water temperature is lower than 80 ° C because the cooling water temperature does not rise to an appropriate level after the engine is started, the ECU 26 reads the mapped catalyst temperature and sets the second threshold value. Compare with The second threshold is preferably set to a temperature index of 625 ° C. (ST23).

When it is confirmed in step ST23 that the catalyst temperature is lower than or equal to the second threshold value, the ECU 26 determines that the water pump driving condition is not established, thereby preventing the water pump 28 from being driven and maintaining the state (ST24).

The state in which the driving of the water pump 28 is prevented by the step ST24 is maintained until the ECU 26 confirms the establishment of the set first release condition. The first release condition is established when the cylinder block water temperature exceeds the first threshold or when the cylinder head water temperature exceeds the set fourth threshold. Thus, the driving prevention state of the water pump 28 is maintained while the first release condition is not satisfied (ST25).

The first threshold is a value set in ST22, the fourth threshold is preferably set to a temperature index of 110 ° C.

On the other hand, when the coolant is sufficiently heated after the engine is started in step ST22 so that the cylinder block water temperature is greater than or equal to 80 ° C, the first threshold value, the ECU 26 compares the mapped catalyst temperature with the set third threshold value. It is determined whether the pump 28 is driven. Preferably, the third threshold value is set to a temperature index of 480 ° C. (ST26).

When it is confirmed in step ST26 that the catalyst temperature is lower than or equal to the third threshold, the ECU determines that the water pump driving condition is not satisfied, thereby preventing the water pump 28 from being driven and maintaining the state (ST27).

The state in which the driving of the water pump 28 is prevented by the step ST27 is maintained until the ECU 26 confirms the establishment of the set second release condition. The second release condition is established when the mapped exhaust gas temperature exceeds a set fifth threshold or when the cylinder head water temperature exceeds the fourth threshold. Thus, while the second release condition is not satisfied, the driving prevention state of the water pump 28 is maintained (ST28).

The fourth threshold is a value set in step ST25, and the fifth threshold is preferably set to a temperature index of 405 ° C.

And the catalyst temperature exceeds the second threshold in step ST23, the first release condition is established in step ST25, the catalyst temperature exceeds the third threshold in step ST26, or the second release condition in step ST28. In either case, the ECU 26 determines that the driving condition of the water pump 28 is established (ST29).

When it is confirmed in step ST29 that the driving condition of the water pump 28 is established, the ECU 26 outputs a control signal for driving the actuator 27 connected to the water pump 28 to output the actuator ( The water pump 28 interlocked with the 27 is driven (ST30).

According to the water pump control method of the vehicle of the present invention, it is possible to control whether or not the water pump is driven in consideration of the temperature of the cooling water, the temperature of the exhaust gas and the temperature of the catalyst when starting the engine, thereby reducing the amount of THC generated in the exhaust gas It works.

For example, applying the present invention to a 1.6 DOHC A / T vehicle, it can be seen that the THC content is reduced by about 16% compared to the non-application. Accordingly, in the water-cooled gasoline engine driven by the water pump, an exhaust gas improvement effect similar to that described above can be expected.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Therefore, the above description does not limit the scope of the following claims.

Claims (5)

(a) When the control unit for controlling the operating state of the engine by receiving a signal detected by the in-vehicle sensing means in a vehicle having a cooling system, and confirms the start of the engine through the detection signal of the sensing means, Determining whether the water temperature of the cylinder block reaches a set first threshold value; (b) if the water temperature of the cylinder block falls below the set first threshold, the control unit reads the stored catalyst temperature and compares it with the set second threshold to determine whether to drive the water pump of the cooling system. Wow; (c) if the water temperature of the cylinder block does not fall below the set threshold, the control unit reads the catalyst temperature and determines whether to drive the water pump of the cooling system by comparing with the set third threshold; ; and (d) when the driving condition of the water pump is established, driving the water pump by applying a control signal to the actuator by the control unit. The method of claim 1, wherein step (b) If it is confirmed that the cylinder block water temperature is lower than the first threshold, the control unit reads a mapped catalyst temperature and compares it with the second threshold; If it is confirmed that the catalyst temperature is equal to or less than the second threshold, the control unit determines that the water pump driving condition is not satisfied and prevents the water pump from driving; And when the driving of the water pump is prevented, the control unit comprises maintaining the driving prevention state of the water pump until the first set release condition is established. The method of claim 2, wherein the first release condition, And the cylinder block water temperature exceeds the first threshold value, or the cylinder head water temperature of the engine exceeds a set fourth threshold value. According to claim 1, wherein step (c) is If it is confirmed that the cylinder block water temperature is greater than or equal to the first threshold, the control unit compares a mapped catalyst temperature with the third threshold; If it is confirmed that the catalyst temperature is less than or equal to the third threshold, the control unit determines that a water pump driving condition is not established and prevents driving of the water pump; And when the driving of the water pump is prevented, the control unit comprises maintaining the driving prevention state of the water pump until the set second release condition is established. The method of claim 4, wherein the second release condition, Wherein the mapped exhaust gas temperature exceeds the set fifth threshold or the cylinder head water temperature detected by the cylinder head temperature sensor mounted on the engine exceeds the set fourth threshold. Control method.