SYSTEM AND METHOD FOR CONTROLLING WATER PUMP OF VEHICLE HAVING WATER-COOLED INTERCOOLER

Abstract

A water pump control system of a vehicle having a water-cooled intercooler includes: the water-cooled intercooler cooling intake air that is injected from the outside through heat exchange with coolant; an electric water pump that selectively supplies coolant to the water-cooled intercooler using an electric motor; and a controller that controls the electric water pump using a heat releasing amount of intake air passing through the water-cooled intercooler.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and the benefit of Korean Patent Application No. 10-2014-0150106 filed on Oct. 31, 2014, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system and method for controlling a water pump of a vehicle having a water-cooled intercooler. More particularly, the present invention relates to a system and method for controlling a water pump of a vehicle having a water-cooled intercooler that can effectively cool compressed air that is supplied to an engine through a water-cooled intercooler.

2. Description of Related Art

In general, a turbocharger is a device that rotates a turbine using pressure of an exhaust gas that is discharged from an engine and that enhances output of the engine by supplying air of a high pressure to a combustion chamber of the engine using torque thereof.

However, density of air that is quickly compressed through the turbocharger is lowered by absorbing heat occurring in a compression process, and supply efficiency of air that is supplied to the combustion chamber of the engine is resultantly lowered.

In order to solve such a problem, compressed air having passed through the turbocharger is cooled through an intercooler that is disposed on an intake line to be supplied to the combustion chamber of the engine through a throttle valve. That is, by cooling air that is compressed through the turbocharger through the intercooler, air of a high density may be supplied to the combustion chamber of the engine and output of the engine can be improved.

As a conventionally intercooler, an air-cooled intercooler that cools air that is mostly turbocharged by air is mostly used.

However, currently, a water-cooled intercooler that is integrally formed with an intake manifold and that cools turbocharged air using a coolant has been developed. Coolant flowing inside of such a water-cooled intercooler is adjusted by operation of an electric water pump (EWP).

However, because operation of a conventional EWP is simply controlled according to an outlet temperature of the water-cooled intercooler without considering an environment condition of a region while a vehicle drives, there is a problem that turbocharged air that is injected into a combustion chamber of an engine is actively controlled.

Therefore, development of a control strategy for effectively controlling the water-cooled intercooler and the EWP is urgently requested.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a system and method for controlling a water pump of a vehicle having a water-cooled intercooler having advantages of being capable of controlling operation of an EWP by estimating a heat releasing amount of the water-cooled intercooler.

The present invention further provides a system and method for controlling a water pump of a vehicle having a water-cooled intercooler having advantages of being capable of reducing fuel consumption of the vehicle by minimizing operation of an EWP.

An aspect of the present invention provides a water pump control system of a vehicle having a water-cooled intercooler, including the water-cooled intercooler that cools intake air that is injected from the outside through heat exchange with a coolant, an EWP that selectively supplies the coolant to the water-cooled intercooler using an electric motor, and a control unit that controls the EWP using a heat releasing amount of intake air passing through the water-cooled intercooler.

The water pump control system may further include a first temperature sensor that is provided at the front end of the water-cooled intercooler to measure a temperature of inflow air that is injected into the water-cooled intercooler, and a second temperature sensor that is provided at the rear end of the water-cooled intercooler to measure a temperature of inflow air that is discharged from the water-cooled intercooler.

The control unit may calculate a heat releasing amount of intake air from a difference between intake temperatures that are detected by the first temperature sensor and the second temperature sensor and an intake air amount that passes through the water-cooled intercooler.

The heat releasing amount of intake air may be calculated by the equation

Q=c·m·dT,

where Q may be a heat releasing amount of intake air, c may be a specific heat of intake air, m may be an intake amount passing through the water-cooled intercooler, and dT may be a temperature difference between the front end and the rear end of the water-cooled intercooler.

The water pump control system may further include a second temperature sensor that is provided at the rear end of the water-cooled intercooler to measure a temperature of inflow air that is discharged from the water-cooled intercooler, a turbocharger including a turbine that rotates by exhaust gas that is discharged from a combustion chamber of the engine and a compressor that rotates by interlocking with rotation of the turbine and that compresses the intake air, and a hot-film mass air flow (HFM) sensor that is provided at the front end of the compressor, wherein the control unit may calculate a heat releasing amount of intake air from a temperature of intake air that is detected by the HFM sensor, a temperature of intake air that is detected by the second temperature sensor, and an air amount passing through the water-cooled intercooler.

The control unit may estimate a temperature of the front end of the water-cooled intercooler using a temperature that is detected by the HFM sensor.

The control unit may turn on operation of the EWP if a heat releasing amount of intake air is smaller than a predetermined value, and may turn off operation of the EWP if a heat releasing amount of intake air is a predetermined value or more.

The predetermined value may be stored as map data according to engine revolutions per minute (RPM) and an engine load.

The predetermined value may increase as engine RPM increases and increase as an engine load increases.

Another embodiment of the present invention provides a method of controlling a water pump of a vehicle having a water-cooled intercooler, including calculating a heat releasing amount of intake air passing through a water-cooled intercooler that cools intake air that is injected from the outside to supply the intake air to a combustion chamber of an engine, and controlling an EWP that supplies coolant to the water-cooled intercooler according to a heat releasing amount of the intake air.

The calculating of a heat releasing amount may include detecting a temperature of the front end and the rear end of the water-cooled intercooler, measuring a temperature difference of intake air passing through the water-cooled intercooler from a temperature of the front end and the rear end of the water-cooled intercooler, and calculating a heat releasing amount of intake air passing through the water-cooled intercooler using a specific heat of air passing through the water-cooled intercooler, an air amount passing through the water-cooled intercooler, and the temperature difference.

The calculating of a heat releasing amount may include estimating a temperature of the front end of the water-cooled intercooler from a temperature that is detected at an HFM sensor that is provided at the front end of a turbocharger that compresses air that is injected into the combustion chamber of the engine, detecting a temperature of the rear end of the water-cooled intercooler, measuring a temperature difference of intake air passing through the water-cooled intercooler from the estimated temperature of the front end of the water-cooled intercooler and the temperature of the rear end of the water-cooled intercooler, and calculating a heat releasing amount of intake air passing through the water-cooled intercooler using a specific heat of air passing through the water-cooled intercooler, an air amount passing through the water-cooled intercooler, and the temperature difference.

The controlling of an EWP may include determining whether the heat releasing amount of intake air is smaller than a predetermined value, and turning on operation of the EWP if a heat releasing amount of the intake air is smaller than a predetermined value and turning off operation of the EWP if a heat releasing amount of the intake air is a predetermined value or more.

The predetermined value may be stored as map data according to engine RPM and an engine load.

The predetermined value may increase as engine RPM increases and may increase as an engine load increases.

According to a system and method for controlling a water pump of a vehicle having a water-cooled intercooler by an aspect of the present invention, by controlling an EWP through a heat releasing amount of intake air passing through the water-cooled intercooler in consideration of an environment condition (atmosphere temperature, pressure), compared with an existing control method of monitoring and controlling only a target temperature of the rear end of an intercooler, operation of the EWP can be more accurately controlled.

Further, by optimizing an operation time of an EWP in consideration of an environment condition, fuel consumption of a vehicle is improved.

In addition, because an intake temperature of the front end of a water-cooled intercooler may be estimated through an HFM sensor that is provided at the front end of a compressor, production cost of a vehicle can be reduced.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a configuration of a water pump control system of a vehicle having a water-cooled intercooler according to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart illustrating a method of controlling a water pump of a vehicle having a water-cooled intercooler.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

Further, in the drawings, size and thickness of each element are randomly represented for better understanding and ease of description, but the present invention is not limited thereto, and the thickness of several portions and areas are exaggerated for clarity.

Hereinafter, a water pump control system of a vehicle having a water-cooled intercooler according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view illustrating a configuration of a water pump control system of a vehicle having a water-cooled intercooler according to an exemplary embodiment of the present invention. As shown in FIG. 1, a water pump control system of a vehicle having a water-cooled intercooler according to an exemplary embodiment of the present invention includes an intake line 150, a turbocharger 130, an intercooler 120, an electric water pump (EWP) 128, an engine 110, and a controller 170.

The turbocharger 130 rotates a turbine 132 by exhaust gas that is discharged to an exhaust line 160, and the turbine 132 compresses intake air that is injected from external air flowing through the intake line 150 while rotating by interlocking with rotation thereof and supplies the compressed intake air to a combustion chamber 112 of the engine 110.

A hot-film mass air flow (HFM) sensor 140 is provided at the front end of the compressor 134 of the turbocharger 130. The HFM sensor 140 may measure an amount and temperature of intake air that is injected from the outside therethrough. The temperature of the intake air that is detected by the HFM sensor 140 is provided to the controller 170.

The water-cooled intercooler 120 cools the intake air flowing through the intake line 150. In this case, the water-cooled intercooler 120 cools intake air that is injected from the outside through heat exchange with a coolant. In this case, the coolant that is heated by cooling intake air in the water-cooled intercooler 120 is cooled through a radiator 126.

A second temperature sensor 124 that measures the temperature of intake air that is discharged from the water-cooled intercooler 120 is provided at the rear end of the water-cooled intercooler 120. A first temperature sensor 122 that measures the temperature of intake air that is injected into the water-cooled intercooler 120 is provided at the front end of the water-cooled intercooler 120. The temperatures of intake air that are detected by the first temperature sensor 122 and the second temperature sensor 124 are provided to the controller 170.

That is, the first temperature sensor 122 measures the temperature of intake air that is injected into the water-cooled intercooler 120, and when estimating a temperature of the front end of the water-cooled intercooler 120 by measuring the temperature of the front end of a compressor 134 through the HFM sensor 140, it is unnecessary to have the first temperature sensor 122.

The EWP 128 selectively supplies the coolant that cools the intake air using an electric motor to the water-cooled intercooler 120. That is, when the temperature of the intake air passing through the intercooler 120 increases, by supplying the coolant from the EWP 128 to the intercooler 120, the temperature of the intake air is lowered. In contrast, when the temperature of the intake air passing through the intercooler 120 is lowered, the coolant is blocked from being supplied from the EWP 128.

The controller 170 may be provided as at least one processor operating by a predetermined program, and the predetermined program performs each step of a method of controlling a water pump of a vehicle having the water-cooled intercooler 120 according to an exemplary embodiment of the present invention.

The controller 170 controls operation of the turbocharger 130, the EWP 128, and the engine 110. Particularly, the controller 170 controls the EWP 128 using a heat releasing amount of intake air passing through the water-cooled intercooler 120.

According to an exemplary embodiment of the present invention, a heat releasing amount of the intake air may be calculated from a difference between intake temperatures that are detected by the first temperature sensor 122 and the second temperature sensor 124 and an intake air amount passing through the water-cooled intercooler 120.

That is, a heat releasing amount of the intake air may be calculated by Equation 1.

Q=c·m·dT  (Equation 1)

Here, Q is a heat releasing amount of intake air, c is a specific heat of intake air, m is an intake air amount passing through the water-cooled intercooler 120, and dT is a temperature difference between the front end and the rear end of the water-cooled intercooler 120.

According to another exemplary embodiment of the present invention, a heat releasing amount of the intake air may be calculated from a temperature of intake air that is detected by the HFM sensor 140, a temperature of intake air that is detected by the second temperature sensor 124, and an air amount passing through the water-cooled intercooler 120.

That is, the controller 170 may estimate a temperature of intake air at the front end of the water-cooled intercooler 120 from the temperature of intake air that is detected by the HFM sensor 140.

Specifically, the intake line 150 including the turbocharger 130 is one isolated system, and an intake process before and after being compressed through the compressor 134 may be assumed to be an isentropic compression process.

First, a temperature of intake air is measured at the front end of the compressor 134 by the HFM sensor 140. In this case, the temperature of intake air before being compressed through the compressor 134 is the temperature of intake air that is measured through the HFM sensor 140.

Because an intake process before and after being compressed through the compressor 134 is an isentropic compression process, the temperature of intake air before and after being compressed through the compressor 134 has a relationship of Equation 2.

$\begin{array}{cc}\Delta T\left(T_2-T_1\right)=P_c·\frac{1}{c_p}·\frac{1}{\stackrel{.}{m}}& \left(\mathrm{Equation}2\right)\end{array}$

Here, T1 is a temperature of intake air before being compressed through the compressor 134, T2 is a temperature of intake air after being compressed through the compressor 134, Pc is work of air that is compressed through the compressor 134, Cp is a constant pressure specific heat, and {dot over (m)} is a mass flow rate of air that is compressed through the compressor 134.

A pressure of intake air before and after being compressed through the compressor 134 has a relationship of Equation 3.

$\begin{array}{cc}\frac{T_2}{T_1}=\frac{P_1}{P_2}& \left(\mathrm{Equation}3\right)\end{array}$

Here, T1 is a temperature of intake air before being compressed through the compressor 134, T2 is a temperature of intake air after being compressed through the compressor 134, P1 is a pressure of intake air before being compressed through the compressor 134, and P2 is a pressure of intake air after being compressed through the compressor 134.

An intake temperature of the front end of the water-cooled intercooler 120 may be estimated through the HFM sensor 140 that is provided at the front end of the compressor 134 with a method. Therefore, because it is unnecessary to have a separate temperature sensor at the front end of the water-cooled intercooler 120, a production cost of a product can be reduced.

The controller 170 controls the EWP 128 using a heat releasing amount of the intake air.

Specifically, if a heat releasing amount of intake air is smaller than a predetermined value, the controller 170 turns on operation of the EWP 128, and if a heat releasing amount of intake air is a predetermined value or more, the controller 170 turns off operation of the EWP 128.

A heat releasing amount of the intake air being smaller than a predetermined value device that a temperature change of intake air that passes through the water-cooled intercooler 120 is small. That is, it device a case in which intake air is not cooled through the water-cooled intercooler 120. Therefore, by turning on operation of the EWP 128, intake air passing through the water-cooled intercooler 120 is cooled.

In contrast, a heat releasing amount of the intake air being a predetermined value or more device that a temperature change of intake air that passes through the water-cooled intercooler 120 is large. That is, it device a case in which intake air is fully cooled through the water-cooled intercooler 120. Therefore, by turning off operation of the EWP 128, cooling of intake air passing through the water-cooled intercooler 120 is stopped.

Here, the predetermined value may be changed according to engine RPM and an engine load. That is, the predetermined value is previously stored at the controller 170 in a map data form according to engine RPM and an engine load. In this case, as engine RPM increases, the predetermined value increases, and as an engine load increases, the predetermined value increases.

Therefore, when a vehicle drives in a high speed and high load condition, the EWP 128 operates much more compared with when a vehicle drives in a low speed and low load condition.

Hereinafter, a method of controlling a water pump of a vehicle having a water-cooled intercooler according to an exemplary embodiment of the present invention will be described in detail.

FIG. 2 is a flowchart illustrating a method of controlling a water pump of a vehicle having a water-cooled intercooler.

As shown in FIG. 2, an intake temperature of the rear end of the water-cooled intercooler 120 and an intake temperature of the front end of the water-cooled intercooler 120 are measured through the second temperature sensor 124 and the first temperature sensor 122, respectively (S10). The controller 170 calculates an intake temperature difference dT between the front end and the rear end of the water-cooled intercooler 120 from the intake temperature that is measured through the first temperature sensor 122 and the second temperature sensor 124 (S20).

Alternatively, an intake temperature of the rear end of the water-cooled intercooler 120 is measured through the second temperature sensor 124, and an intake temperature of the front end of the water-cooled intercooler 120 is estimated using a temperature that is measured through the HFM sensor 140 (S10). In this case, an intake temperature of the front end of the water-cooled intercooler 120 may be estimated through Equations 2 and 3. The controller 170 calculates an intake temperature difference dT of the front end and the rear end of the water-cooled intercooler 120 from an intake temperature of the front end of the water-cooled intercooler 120 that is estimated through the HFM sensor 140 and an intake temperature that is measured through the second temperature sensor (S20).

The controller 170 calculates a heat releasing amount Q of intake air using a temperature difference dT of intake air passing through the water-cooled intercooler 120 that is calculated at step S20, an intake air amount m passing through the water-cooled intercooler 120, and a specific heat of intake air (S30). In this case, the heat releasing amount Q of intake air may be calculated by Equation 1.

The controller 170 determines whether a heat releasing amount Q of intake air is smaller than a predetermined value (S40).

If a heat releasing amount Q of intake air is smaller than a predetermined value, the controller 170 turns on operation of the EWP 128 to cool intake air passing through the water-cooled intercooler 120 (S60).

If a heat releasing amount Q of intake air is a predetermined value or more, the controller 170 turns off operation of the EWP 128 to stop cooling intake air passing through the water-cooled intercooler 120 (S50).

As described above, the predetermined value is previously stored at the controller 170 in a map data form according to engine RPM and an engine load, and as engine RPM increases, the predetermined value increases, and as an engine load increases, the predetermined value increases.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.

Claims

1. A water pump control system of a vehicle having a water-cooled intercooler, the water pump control system comprising:

the water-cooled intercooler that cools an intake air that is injected from an outside through heat exchange with a coolant;

an electric water pump (EWP) that selectively supplies the coolant to the water-cooled intercooler using an electric motor; and

a controller that controls the EWP using a heat releasing amount of the intake air passing through the water-cooled intercooler.

2. The water pump control system of claim 1, further comprising:

a first temperature sensor that is provided at a front end of the water-cooled intercooler to measure a temperature of the inflow air that is injected into the water-cooled intercooler; and

a second temperature sensor that is provided at a rear end of the water-cooled intercooler to measure a temperature of the inflow air that is discharged from the water-cooled intercooler.

3. The water pump control system of claim 2, wherein the controller determines a heat releasing amount of intake air from a difference between intake temperatures that are detected by the first temperature sensor and the second temperature sensor and an intake air amount that passes through the water-cooled intercooler.

4. The water pump control system of claim 3, wherein the heat releasing amount of intake air is determined by an equation

Q=c·m·dT

where Q is a heat releasing amount of intake air, c is a specific heat of intake air, m is an intake amount passing through the water-cooled intercooler, and dT is a temperature difference between the front end and the rear end of the water-cooled intercooler.

5. The water pump control system of claim 1, further comprising:

a second temperature sensor that is provided at a rear end of the water-cooled intercooler to measure a temperature of the inflow air that is discharged from the water-cooled intercooler;

a turbocharger comprising a turbine that rotates by exhaust gas that is discharged from a combustion chamber of an engine and a compressor that rotates by interlocking with a rotation of the turbine and that compresses the intake air; and

a hot-film mass air flow (HFM) sensor that is provided at a front end of the compressor,

wherein the controller determines a heat releasing amount of intake air from a temperature of intake air that is detected by the HFM sensor, a temperature of intake air that is detected by the second temperature sensor, and an air amount passing through the water-cooled intercooler.

6. The water pump control system of claim 5, wherein the controller estimates a temperature of a front end of the water-cooled intercooler using a temperature that is detected by the HFM sensor.

7. The water pump control system of claim 1, wherein the controller turns on operation of the EWP when a heat releasing amount of intake air is smaller than a predetermined value and turns off operation of the EWP when a heat releasing amount of intake air is a predetermined value or more.

8. The water pump control system of claim 7, wherein the predetermined value is stored as map data according to engine revolutions per minute (RPM) and an engine load.

9. The water pump control system of claim 8, wherein the predetermined value increases as engine RPM increases and increases as an engine load increases.

10. A method of controlling a water pump of a vehicle having a water-cooled intercooler, the method comprising:

determining a heat releasing amount of an intake air passing through a water-cooled intercooler that cools the intake air that is injected from an outside to supply the intake air to a combustion chamber of an engine; and

controlling an electric water pump (EWP) that supplies coolant to the water-cooled intercooler according to a heat releasing amount of the intake air.

11. The method of claim 10, wherein the determining of the heat releasing amount comprises:

detecting a temperature of a front end and a rear end of the water-cooled intercooler;

measuring a temperature difference of the intake air passing through the water-cooled intercooler from a temperature of the front end and the rear end of the water-cooled intercooler; and

determining a heat releasing amount of intake air passing through the water-cooled intercooler using a specific heat of air passing through the water-cooled intercooler, an air amount passing through the water-cooled intercooler, and the temperature difference.

12. The method of claim 10, wherein the determining of the heat releasing amount comprises:

estimating a temperature of the front end of the water-cooled intercooler from a temperature that is detected at a hot-film mass air flow (HFM) sensor that is provided at a front end of a turbocharger that compresses air that is injected into the combustion chamber of the engine;

detecting a temperature of the rear end of the water-cooled intercooler;

measuring a temperature difference of intake air passing through the water-cooled intercooler from the estimated temperature of the front end of the water-cooled intercooler and the temperature of the rear end of the water-cooled intercooler; and

determining a heat releasing amount of intake air passing through the water-cooled intercooler using a specific heat of air passing through the water-cooled intercooler, an air amount passing through the water-cooled intercooler, and the temperature difference.

13. The method of claim 10, wherein the controlling of the EWP comprises:

determining whether the heat releasing amount of the intake air is smaller than a predetermined value; and

turning on operation of the EWP when a heat releasing amount of the intake air is smaller than a predetermined value, and turning off the operation of the EWP when the heat releasing amount of the intake air is a predetermined value or more.

14. The method of claim 13, wherein the predetermined value is stored as map data according to engine RPM and an engine load.

15. The method of claim 14, wherein the predetermined value increases as engine RPM increases and increases as an engine load increases.