KR20180112514A - Internal combustion engine system and method for operating the same - Google Patents

Abstract

The present invention relates to an engine system that collects condensation water generated by a temperature difference between an EGR gas and intake air and injects the water to prevent the condensation water from interrupting a flow of the intake air, and to improve utilization of the condensation water and an effect of low-temperature combustion, and an operating method thereof. The engine system includes: an engine; an injection unit having a water injector for injecting water toward an intake manifold of the engine or an intake passage, and a water tank for storing the water supplied to the water injector; an EGR unit having an EGR conduit connecting an intake duct of the engine or an exhaust duct, and an EGR cooler and an EGR valve installed to the EGR duct; and a condensation water tank connected to one side of the EGR conduit to store the condensation water generated by the temperature difference between the EGR gas passing through the EGR conduit and the intake air passing through the intake duct of the engine. A condensation water supply conduit is connected to the condensation water tank and the water tank, and the condensation water supply conduit is provided with a pump for pumping the condensation water from the condensation water tank to the water tank.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an internal combustion engine,

The present invention relates to an engine system and a method of operating the same. More specifically, the present invention relates to an engine system and a method of operating the engine system. More particularly, And to a method of operating the engine system.

Various technologies for improving the fuel efficiency by suppressing nitrogen oxide, hydrocarbons and the like by reducing the combustion heat of the internal combustion engine at the time of combustion of the internal combustion engine of the vehicle and reducing the mixture ratio of air and fuel have been researched and developed.

Exhaust gas recirculation (EGR) systems or water injection systems have been researched and developed as typical technologies for reducing combustion heat and nitrogen oxides and improving fuel efficiency.

The EGR system may include an EGR conduit for circulating the EGR gas from the exhaust system of the engine to the intake system side, an EGR cooler for cooling the temperature of the EGR gas, and an EGR valve for regulating the flow rate of the EGR gas.

On the other hand, in such an EGR system, water vapor is generated due to the temperature difference between the EGR gas and the intake air, and this water vapor flows on the inner surface of the intake conduit and can be collected as condensed water in the intercooler, It could cause corrosion. In addition, water vapor or condensed water may collide with the wheel of the compressor to damage internal components of the compressor. In winter, condensate may be excessively collected inside the intercooler, and condensation water may icing inside the intercooler. Accordingly, the flow of the intake air may be interrupted.

The water injection system suppresses nitrogen oxides, hydrocarbons and the like by lowering the temperature of the combustion chamber by injecting water into the intake or fuel-air mixture or directly into the combustion chamber side of the engine, The fuel ratio can be improved by reducing the mixing ratio.

On the other hand, the water injection system is required to inject water of 30% or more of the average fuel consumption per day, so that the water tank for storing water has a large capacity.

As described above, the conventional water injection system has a disadvantage in that the water tank for storing the water to be supplied to the water injector has a large capacity, so that the installation space of the engine room can be further narrowed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to provide a compressor and a compressor capable of preventing condensation water from interfering with the flow of intake air by collecting condensed water generated due to temperature difference between EGR gas and intake air, And an object of the present invention is to provide an engine system and a driving method thereof that can enhance a low temperature combustion effect.

According to an aspect of the present invention,

engine;

A water injection unit having a water injector for injecting water toward the intake machine or the cylinder side of the engine and a water tank for storing water supplied to the water injector side;

An EGR conduit connecting between the intake conduit and the exhaust conduit of the engine; an EGR unit having an EGR cooler and an EGR valve installed in the EGR conduit; And

And a condensate tank connected to one side of the EGR conduit for storing condensed water generated by a temperature difference between an EGR gas passing through the EGR conduit and an intake air passing through an intake conduit of the engine,

A condensate supply conduit is connected between the condensate tank and the water tank and a pump that pumps the condensate water from the condensate tank to the water tank may be installed in the condensate supply conduit.

A connection pipe may be connected to one side of the EGR conduit, and the condensate tank may be installed in the connection pipe.

The connection point between the connector and the EGR conduit may be located between the EGR cooler and the EGR valve.

A water separator may be installed at a connection point between the connection pipe and the EGR conduit.

And a first heating means for heating the condensate water tank to prevent the occurrence of freezing in the condensed water tank.

The first heating means may be a first heating conduit installed in the condensate tank, and the first heating conduit may be configured to circulate the engine cooling water.

The condensate tank may be connected to a first liquid replenishment conduit capable of replenishing liquid from an external liquid source.

The water tank may be connected to a second liquid replenishment conduit capable of replenishing liquid from an external liquid source.

The liquid may be at least one of water and oxygenated fuel.

And a mixing unit installed at a portion where the EGR conduit and the intake conduit of the engine are connected to each other.

The mixing unit may include a mixing chamber for mixing high-temperature EGR gas passing through the EGR conduit with low-temperature intake air flowing through the intake conduit.

And a second heating unit for heating the mixing chamber to prevent freezing in the mixing unit.

The second heating means may be a second heating conduit installed in the mixing chamber, and the second heating conduit may be configured to circulate the engine cooling water.

Another aspect of the present invention is a fuel injection system comprising a water injection unit having a water injector injecting water to the engine side and a water tank storing water supplied to the water injector side and an EGR conduit connecting between the intake conduit and the exhaust conduit of the engine An EGR unit, a condensate tank connected to the EGR unit for receiving condensed water generated by a temperature difference between EGR gas and intake air, a condensate supply conduit connecting between the condensate tank and the water tank, A first heating conduit provided in the condensate tank and capable of circulating engine cooling water; and an engine system having a second heating conduit installed in the mixing section and capable of circulating engine cooling water, As a driving method,

If the intake air temperature is lower than the first reference temperature, it is determined whether the temperature of the engine coolant is higher than the second reference temperature.

Controls the flow rate of the engine cooling water circulating through the first and second heating conduits when the temperature of the engine cooling water is higher than the second reference temperature,

The first reference temperature may be a reference temperature for determining whether the condensing water tank and the mixing unit are exposed to low temperature conditions, and the second reference temperature may be a reference temperature for determining whether the engine cooling water is in an overheated state.

The controller controls the flow rate of the engine cooling water for a preset time and blocks the engine cooling water from flowing into the first and second heating conduits when the temperature of the mixing unit is equal to or higher than the third reference temperature, It can be a temperature that does not.

According to the present invention, since the condensed water in the condensate tank can be supplied to the water injection unit side, the low-temperature combustion of the engine can be improved by satisfying the water injection amount, thereby reducing fuel consumption and emission such as NOx Can be effectively improved.

In addition, since the condensed water of the condensed water tank can be selectively and variably supplied to the water tank side of the water injection unit as required, the capacity (size) of the water tank can be greatly reduced, Can be stably secured.

1 is a view showing an engine system according to an embodiment of the present invention.
2 is a view showing an engine system according to another embodiment of the present invention.
3 is a diagram illustrating a method of operating an engine system according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For the sake of convenience, the size, line thickness, and the like of the components shown in the drawings referenced in the description of the present invention may be exaggerated somewhat. The terms used in the description of the present invention are defined in consideration of the functions of the present invention, and thus may be changed depending on the user, the intention of the operator, customs, and the like. Therefore, the definition of this term should be based on the contents of this specification as a whole.

In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

1, an engine system 10 according to an embodiment of the present invention includes an engine 1, a water injection unit 20 that injects water into an intake system or a cylinder side of the engine 1, And an EGR unit (90) connected between the intake conduit (2) and the exhaust conduit (6) of the intake manifold (11).

The engine 1 may have one or more cylinders 5. According to one example, the engine 1 may be a multi-cylinder internal combustion engine having a plurality of cylinders 5.

The engine 1 may be connected to an intake system that supplies intake air to each cylinder 5 and an exhaust system that exhausts exhaust gas from each cylinder 5.

The intake system of the engine 1 includes an air filter 3a provided adjacent to the inlet side of the intake conduit 2, a compressor 3b disposed downstream of the air filter 3a, An intake manifold 3d communicating with an intake port of each cylinder 5, and the like.

The exhaust system of the engine 1 includes an exhaust valve 7a provided adjacent to the outlet side of the exhaust conduit 6, a post-treatment device 8 provided on the upstream side of the exhaust valve 7a, An exhaust manifold 7c communicating with the exhaust port of each cylinder 5, and the like. The post-processing apparatus 8 may be configured by various combinations of the DOC 8a, the DOC and DPF integrated structure 8b, and the SCR 8c.

The compressor 3b and the inflator 7b are connected to each other by a single shaft to constitute a turbocharger and the compressor 3b can be driven as the exhaust gas rotates the inflator 7b.

The water injection unit 20 includes at least one water injector 21 for injecting water into the intake system of the engine 1 or each cylinder side, a water supply unit 25 for supplying water to the water injector 21, An air supply unit 35 for supplying pressurized air to the water supply unit 20 and at least one control valve 40 to which the water supply unit 25 and the air supply unit 35 are connected.

The water injector 21 may be provided on the intake system side and configured to inject water into the cylinder 5 of the engine 1 or the intake air flowing into the intake system of the engine 1. [

1, one water injector 21 may be installed in the intake conduit 2 of the intake system, and in particular, the water injector 21 may be provided between the intercooler 3c and the intake manifold 3d, As shown in FIG. Thus, the water injector 21 can inject water toward the intake manifold 3d of the intake system.

According to another example, as shown in FIG. 2, a plurality of water injectors 21 may be disposed individually corresponding to the plurality of cylinders 5 in the intake manifold 3d of the intake system, and a plurality of water injectors 21 21 can individually spray water onto the respective cylinders 5 of the engine 1.

The control valve 40 may be disposed on the upstream side of the water injector 21. According to one example, the water injector 21 and the control valve 40 may be made of the same body.

The water injection amount of each water injector 21 can be adjusted as the opening degree of the control valve 40 is adjusted. As the opening degree of the control valve 40 is adjusted, the supply amount of water supplied by the water supply part 25 and the amount of water supplied by the air supply part 35 are controlled in accordance with the adjustment of the water injection amount by the control valve 40. [ The water supplied from the water supply unit 25 can be mixed with the pressurized air supplied from the air supply unit 35 and can be transported to the water injector 21 side. The control valve 40 may be an electronic control valve such as a solenoid valve or the like.

According to one example, as shown in Fig. 1, one regulating valve 40 may be disposed on the upstream side of one water injector 21.

According to another example, as shown in Fig. 2, a plurality of regulating valves 40 may be disposed separately on the upstream side of the plurality of water injectors 21. [

The water supply unit 25 includes a water supply conduit 26, a water tank 27 provided at an upstream end of the water supply conduit 26, and a water pump 27 for pumping water to the water injector 21 The water pump 28 may be a water pump.

A water pump 28, a pressure regulator 29a, a pressure gauge 29b, and the like are installed at the downstream end of the water supply conduit 26 and at the middle of the water supply conduit 26 .

The air supply 35 may include an air supply conduit 36, an air tank 37 at an upstream end of the air supply conduit 36, and a compressor 38 for pressurizing the air in the air tank 37 have.

A downstream end of the air supply conduit 36 is connected to the other side of each control valve 40 and a compressor 38 and a pressure regulator 39 may be installed in the middle of the air supply conduit 36.

According to one example, in the case where one regulating valve 40 and one water injector 21 are arranged in the intake conduit 2 of the intake system as in Fig. 1, the downstream end of the water supply conduit 26 is regulated The downstream end of the air supply conduit 36 may be connected to the other side of the regulating valve 40. [

According to another example, when a plurality of regulating valves 40 and a plurality of water injectors 21 are disposed in the intake manifold 3d of the intake system as shown in Fig. 2, A plurality of branch pipes 26a are branched and each branch pipe 26a can be individually connected to one side of each control valve 40. [ A plurality of spray tubes 36a are branched at the downstream end of the air supply conduit 36 and each branch 36a can be individually connected to the other side of each control valve 40. [

A humidity sensor 71 for measuring the humidity of the intake system and a temperature sensor 72 for measuring the temperature of the intake system may be provided on the intake system side of the engine 1. [

The humidity sensor 71 may be installed at one side of the intake conduit 2 and the humidity sensor 71 may be disposed between the downstream end of the intercooler 3c and the intake manifold 3d. The temperature sensor 72 may be installed on one side of the intake manifold 3d.

The control unit (not shown) substitutes the humidity measured by the humidity sensor 71 and the temperature measured by the temperature sensor 72 into a water injection amount map set as a standard condition to adjust the opening degree of the control valve 40, It is possible to control the water injection amount of the water injection valve 21.

The EGR unit 90 includes an EGR conduit 91 connected between the exhaust conduit 6 and the intake conduit 2, an EGR cooler 92 provided in the EGR conduit 91, And an EGR valve 93 installed therein.

A connection pipe 96 is connected to one side of the EGR conduit 91 and a condensate tank 95 may be installed at an end of the connection pipe 96. Condensate water generated by the temperature difference between the EGR gas and the intake air can be received in the condensate tank 95.

1 and 2, the EGR unit 90 may be configured such that the inlet of the EGR conduit 91 is connected to the downstream side of the inflator 7b in the exhaust conduit 6, The outlet of the conduit 91 is connected to the upstream side of the compressor 3b in the intake conduit 2 to constitute a low pressure EGR loop.

According to another embodiment, the EGR unit 90 may be configured such that the inlet of the EGR conduit 91 is connected to the upstream side of the inflator 7b in the exhaust conduit 6 and the outlet of the EGR conduit 91 is connected to the intake conduit 2 To the downstream side of the compressor 3b to constitute a high-pressure EGR loop.

The connecting pipe 96 may be connected at one side of the EGR conduit 91 and the connecting point between the connecting pipe 96 and the EGR conduit 91 may be connected between the EGR cooler 92 and the EGR valve 93 Lt; / RTI >

A water separator 94 for separating moisture contained in the EGR gas may be provided at the connection point between the EGR conduit 91 and the connection pipe 96. The water separator 94 may more effectively collect the condensed water can do.

The mixing unit 100 can be installed at a portion where the EGR conduit 91 and the intake conduit 2 are connected and the mixing unit 100 can mix the high temperature EGR gas passing through the EGR conduit 91 and the intake conduit 2, So that the intake air can be smoothly mixed.

According to one embodiment, the mixing unit 100 may include a mixing chamber 110 to which the EGR conduit 91 and the intake conduit 2 are connected. The cross sectional area of the mixing chamber 110 can be configured to be larger than the cross sectional area of the EGR conduit 91 and the cross sectional area of the intake conduit 2 so that the EGR gas passing through the EGR conduit 91 and the EGR gas passing through the intake conduit 2 The intake air can be mixed more smoothly in the mixing chamber 110.

When the high-temperature EGR gas and the low-temperature intake air are mixed in the mixing unit 100, condensation water may be generated due to the temperature difference between the EGR gas and the intake air, and the condensed water thus generated may flow into the water separator 94 and / 95).

According to an example, the water separator 94 and / or the condensate tank 95 may be positioned below the mixing unit 100, and the condensed water generated in the mixing unit 100 may be supplied to the water separator 94 / RTI > and / or the condensate tank 95, as shown in FIG.

A condensate supply conduit 81 is connected between the condensate tank 95 of the EGR unit 90 and the water tank 27 of the water injection unit 20 and connected to the condensate tank 95 in the middle of the condensate supply conduit 81, And a pump 82 for pumping condensate water from the water tank 27 side to the water tank 27 side. The control unit (not shown) detects a change in the water level of the water tank 27 of the water injection unit 20 and controls the operation of the pump 82, the number of revolutions, the torque, etc. according to the detected change in the water level, 95 can be selectively and variably supplied to the water tank 27 side of the water injection unit 20.

Thereby, the condensed water generated by the temperature difference between the EGR gas and the intake air is collected in the condensed water tank 95, and the condensed water collected in the condensed water tank 95 according to the situation is supplied to the water tank 27 of the water injection unit 20 So that the supply amount of water injected to the intake system side of the engine 1 by the water injection unit 20 can be stably secured.

Since the condensed water in the condensate tank 95 can be variably supplied to the water tank 27 side as needed, even if the capacity of the water tank 27 is made small, the water injection amount For example, the water injection amount corresponding to 30% or more of the daily average fuel consumption amount) can be sufficiently secured.

As described above, according to the present invention, since the condensed water of the condensate tank 95 can be supplied to the water tank 27 side of the water injection unit 20, the low temperature combustion of the engine 1 can be improved by satisfying the water injection amount, It is possible to effectively reduce fuel consumption and emission reduction such as NOx.

Since the condensed water of the condensate tank 95 can be selectively and variably supplied to the water tank 27 side as required, the capacity (size) of the water tank 27 can be greatly reduced, The space for installing the water injection unit 20 in the vicinity can be stably secured.

On the other hand, the first liquid replenishment conduit 51 can be connected to the condensate tank 95 and the liquid supplied from the external liquid source can be replenished to the condensate tank 95 through the first liquid replenishment conduit 51 . According to one example, the liquid that is replenished to the condensate tank 95 may be at least one of water and oxygenated fuel. According to another example, the liquid replenished to the condensate tank 95 may be a mixture of water and oxygenated fuel.

According to an embodiment, the oxygen-containing fuel may be an alcohol containing 60% water and 40% alcohol. Besides, MTBE (methyl tertiary butyl ether), ethanol, TAME (tertiary amyl methyl ether) and ETBE (ethyl tertiary butyl ether) may be used.

For example, when water is replenished into the condensate tank 95 through the first liquid supplement conduit 51, the effect of reducing NOx can be further enhanced by further enhancing the low temperature combustion.

For example, when the oxygen-containing fuel is replenished into the condensate tank 95 through the first liquid supplement conduit 51, the combustion efficiency and the smoke can be improved effectively.

The second liquid replenishment conduit 52 can be connected to the water tank 27 of the water supply unit 25 and the liquid supplied from the external liquid source can be supplied to the water tank 27 through the second liquid replenishment conduit 52 ). ≪ / RTI > According to one example, the liquid that replenishes the water tank 27 may be at least one of water and oxygenated fuel. According to another example, the liquid replenished to the water tank 27 may be a mixture of water and oxygenated fuel.

According to an embodiment, the oxygen-containing fuel may be an alcohol containing 60% water and 40% alcohol. Besides, MTBE (methyl tertiary butyl ether), ethanol, TAME (tertiary amyl methyl ether) and ETBE (ethyl tertiary butyl ether) may be used.

For example, when water is replenished into the water tank 27 through the second liquid supplement conduit 52, the effect of reducing NOx can be further enhanced by further enhancing the low temperature combustion.

For example, when the oxygen-containing fuel is replenished into the water tank 27 through the second liquid supplement conduit 52, the combustion efficiency and the smoke can be effectively improved.

Icing of condensed water or the like may occur in the condensate tank 95 at a low temperature condition (for example, a condition in which the intake air temperature is lower than 0 占 폚). According to the present invention, in order to prevent freezing in the condensate tank 95, it is necessary to heat the condensate tank 95 to an appropriate temperature. As such, for heating of the condensate tank 95, the present invention may include a first heating conduit 61 installed in the condensate tank 95.

The first heating conduit 61 may be installed in a spiral structure on the inside or the outside of the condensate tank 95. In this first heating conduit 61, engine coolant can circulate and the condensed water in the condensate tank 95 is heated to a predetermined temperature while the engine coolant circulates through the first heating conduit 61, Can be prevented from icing at a low temperature condition (for example, a condition of less than 0 캜).

A first cooling water control valve 63 is installed on the inlet side of the first heating conduit 61 and flows into the first heating conduit 61 through opening control of the first cooling water control valve 63, The inflow, flow rate, circulation, etc. of the engine coolant can be controlled.

Icing may occur in the mixing section 100 at a low temperature condition (for example, a condition in which the intake air temperature is lower than 0 占 폚). According to the present invention, it is necessary to heat the mixing chamber 110 of the mixing unit 100 to an appropriate temperature in order to prevent freezing in the mixing unit 100. As described above, in order to heat the mixing unit 100, the present invention may include a second heating conduit 62 installed in the mixing chamber 110.

A second heating conduit 62 may be installed in the mixing chamber 110 of the mixing unit 100 and a second heating conduit 62 may be installed in a spiral structure on the inner or outer surface of the mixing chamber 110 . This second heating conduit 62 is capable of circulating the engine cooling water and heating the condensate in the condensate tank 95 to a constant temperature while the engine cooling water circulates through the second heating conduit 62, Can be prevented from icing at a low temperature condition (for example, a condition of less than 0 캜).

A second cooling water control valve 64 is installed at the inlet side of the second heating conduit 62 and flows into the second heating conduit 62 through opening and closing operations of the second cooling water control valve 64 The inflow, flow rate, circulation, etc. of the engine coolant can be controlled.

The first heating conduit 61 and the second heating conduit 62 may be connected to the engine's water jacket via an engine coolant conduit to which the first heating conduit 61 and the second heating conduit 62 are connected, The engine cooling water passing through the water jacket of the engine can circulate. In particular, the first heating conduit 61 and the second heating conduit 62 may be connected in series or parallel to the water jacket of the engine via an engine coolant conduit.

FIG. 3 is a schematic view showing the operation of the condensing water tank 95 and the condensing water tank 95 by controlling circulation, circulation flow rate, etc. of the engine cooling water passing through the first heating conduit 61 and the second heating conduit 62 of the engine system according to the embodiment of the present invention. And is a flowchart showing an operation method for preventing freezing of the mixing chamber (110).

Referring to FIG. 3, it is possible to measure the intake air temperature flowing into the intake system of the engine 1 by the temperature sensor 72, and the control unit (not shown) determines whether the intake air temperature is smaller than the first reference temperature T1 (S1).

Here, the first reference temperature T1 is a reference temperature for determining whether the condensing water tank 95 and the mixing unit 100 are exposed to low-temperature conditions. For example, the first reference temperature T1 may be set to about 0 占 폚.

If it is determined in S1 that the intake air temperature is higher than the first reference temperature T1, the controller (not shown) controls the first and second cooling water control valves 63 and 64 of the first and second heating conduits 61 and 62, (S1-1). Accordingly, the supply of the engine cooling water to the first and second heating conduits 61 and 62 can be interrupted.

If it is determined in step S1 that the intake air temperature is lower than the first reference temperature T1, the controller (not shown) determines whether the temperature of the engine cooling water circulating through the first and second heating conduits 61 and 62 is lower than the second reference temperature T2 ) (S2).

Here, the second reference temperature T2 is a reference temperature for determining whether the engine coolant is in an overheated state. For example, the second reference temperature T2 may be set to about 80 deg.

If it is determined in step S2 that the engine cooling water is greater than the second reference temperature T2, that is, if it is determined that the engine cooling water is in an overheated state, the controller (not shown) closes the first and second cooling water control valves 63 and 64 (S2-1). Accordingly, the supply of the engine cooling water to the first and second heating conduits 61 and 62 can be interrupted.

If it is determined in step S2 that the engine cooling water is smaller than the second reference temperature T2, that is, if it is determined that the engine cooling water is not in the overheated state, the controller (not shown) controls the first and second cooling water control valves 63 and 64 The flow rate of the engine cooling water circulating through the first and second heating conduits 61 and 62 is controlled for a preset time by adjusting the opening degree (S3).

After controlling the flow rate of the engine cold water for a preset time, the control unit (not shown) determines whether the temperature of the mixing unit 100 is equal to or higher than the third reference temperature T3 (S4).

Here, the third reference temperature T3 is a reference temperature for determining whether a freezing condition can be generated in the mixing chamber 110 of the mixing unit 100. For example, the third reference temperature T3 may be 0 占 폚.

If it is determined in step S4 that the temperature of the mixing unit 100 is equal to or higher than the third reference temperature T3, the control unit (not shown) determines that freezing will not occur in the mixing unit 100, So as to close the valves 63 and 64 (S5).

If it is determined in step S4 that the temperature of the mixing unit 100 is lower than the third reference temperature T3, the controller (not shown) controls to return to step S3.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

10: engine system 20: water injection unit
21: Water injector 25: Water supply part
35: air supply part 40: regulating valve
51: first liquid replenishment conduit 52: second liquid replenishment conduit
61: first heating conduit 62: second heating conduit
90: EGR unit 91: EGR conduit
92: EGR cooler 93; EGR valve
94: Water separator 95: Condensate tank
100: Mixing section 110: Mixing chamber

Claims (16)

engine;
A water injection unit having a water injector for injecting water toward the intake machine or the cylinder side of the engine and a water tank for storing water supplied to the water injector side;
An EGR conduit connecting between the intake conduit and the exhaust conduit of the engine; an EGR unit having an EGR cooler and an EGR valve installed in the EGR conduit; And
And a condensate tank connected to one side of the EGR conduit for storing condensed water generated by a temperature difference between an EGR gas passing through the EGR conduit and an intake air passing through an intake conduit of the engine,
A condensate supply conduit is connected between the condensate tank and the water tank and a pump is provided in the condensate supply conduit to pump the condensate water from the condensate tank to the water tank. The method according to claim 1,
Wherein a connection pipe is connected to one side of the EGR conduit, and the condensate tank is installed in the connection pipe. The method of claim 2,
Wherein the connection point between the connector and the EGR conduit is located between the EGR cooler and the EGR valve. The method of claim 3,
And a water separator is installed at a connection point between the connection pipe and the EGR conduit. The method according to claim 1,
Further comprising first heating means for heating the condensate tank to prevent the occurrence of freezing in the condensate tank. The method of claim 5,
Wherein the first heating means is a first heating conduit installed in the condensate tank, and the engine cooling water is circulated in the first heating conduit. The method according to claim 1,
Wherein the condensate tank is connected to a first liquid replenishment conduit capable of replenishing liquid from an external liquid source. The method of claim 7,
Wherein the liquid is at least one of water and oxygenated fuel. The method according to claim 1,
Wherein the water tank is connected to a second liquid replenishment conduit capable of replenishing liquid from an external liquid source. The method of claim 9,
Wherein the liquid is at least one of water and oxygenated fuel. The method according to claim 1,
Further comprising a mixing portion provided at a portion where the EGR conduit and the intake conduit of the engine are connected. The method of claim 11,
Wherein the mixing section includes a mixing chamber for mixing high-temperature EGR gas passing through the EGR conduit with low-temperature intake air flowing through the intake conduit. The method of claim 12,
Further comprising second heating means for heating the mixing chamber to prevent generation of freezing in the mixing portion. 14. The method of claim 13,
Wherein the second heating means is a second heating conduit installed in the mixing chamber, and the engine cooling water is circulated in the second heating conduit. A water injection unit having a water injector injecting water to the engine side and a water tank storing water supplied to the water injector side, an EGR conduit having an EGR conduit connecting between the intake conduit and the exhaust conduit of the engine, A condensate tank connected to the unit for receiving condensate produced by the temperature difference between the EGR gas and the intake air; a condensate supply conduit connecting the condensate tank and the water tank; and an EGR conduit and an intake conduit of the engine, A first heating conduit installed in the condensed water tank and capable of circulating the engine cooling water and a second heating conduit installed in the mixing unit and capable of circulating the engine cooling water,
If the intake air temperature is lower than the first reference temperature, it is determined whether the temperature of the engine coolant is higher than the second reference temperature.
Controls the flow rate of the engine cooling water circulating through the first and second heating conduits when the temperature of the engine cooling water is higher than the second reference temperature,
Wherein the first reference temperature is a reference temperature for determining whether the condensing water tank and the mixing unit are exposed to low temperature conditions and the second reference temperature is a reference temperature for determining whether the engine cooling water is in an overheated state. 16. The method of claim 15,
When the temperature of the mixing unit is equal to or higher than the third reference temperature after the flow rate of the engine cooling water is controlled for the preset time, the engine cooling water is prevented from flowing into the first and second heating conduits,
Wherein the third reference temperature is a temperature at which freezing does not occur in the mixing unit.

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