JP2018087539A - Warming-up device of exhaust recirculation valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a warming-up device of an exhaust recirculation valve capable of quickly warming up an exhaust recirculation valve after start of an on-vehicle engine.SOLUTION: A warming-up device for warming-up an EGR valve 14 includes: a branch passage 26 branched from a refrigerant passage 25 connecting a compressor 22 and a condenser 23 in a refrigerant circuit 21 of an air-conditioning system in a vehicle, and made confluent with the refrigerant passage 25 again after passing through the inside of the EGR valve 14; and selector valves 27, 28 configured to switch between a state of permitting circulation of refrigerant in the branch passage 26 and a state of prohibiting the circulation of the refrigerant. The EGR valve 14 is warmed up with heat of refrigerant whose temperature is increased by compression from the compressor 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a warm-up device for an exhaust gas recirculation valve that warms an exhaust gas recirculation valve provided in an in-vehicle engine.

  An exhaust gas recirculation (EGR) valve for controlling the flow rate of exhaust gas recirculated from the exhaust passage of the in-vehicle engine to the intake passage is provided in the exhaust gas recirculation system of the in-vehicle engine. When the EGR valve is in a cold state, the water vapor in the EGR gas is cooled when the EGR valve passes and condensed water is generated. And the component of an EGR valve may corrode by the condensed water.

  Therefore, in many on-vehicle engines that employ an exhaust gas recirculation system, the cooling water that has passed through the water jacket flows through the inside of the EGR valve, and the EGR valve is warmed up by the heat of the cooling water. The exhaust gas recirculation is started after the EGR valve is sufficiently warmed. Furthermore, in Patent Document 1, in an exhaust gas recirculation device applied to an in-vehicle engine with an intercooler, an EGR valve is installed at an intake outlet portion of the intercooler from which intake air that has become hot due to compression flows out. It is described that the warm-up of the EGR valve is promoted by the heat of the intake air that has become high temperature due to compression in the cooler.

JP 07-293356 A

  When the EGR valve is warmed up with the heat of the cooling water, if the cooling water temperature at the time of starting the engine is low, it takes time until the cooling water temperature increases to the temperature required for warming up the EGR valve. The completion of warm-up of the valve may be delayed, and exhaust gas recirculation may not be started for a while after the engine is started. Further, while the vehicle-mounted engine is operated at a low output, the compression of the intake air by the intercooler is limited. Therefore, even when the EGR valve is warmed up by the heat of the intake air after passing through the intercooler, if the in-vehicle engine is not operated at a high output immediately after the engine starts, it takes time to complete the warming up of the EGR valve, The start of exhaust gas recirculation may be delayed.

  The present invention has been made in view of such circumstances, and the problem to be solved is to warm the exhaust gas recirculation valve that can warm up the exhaust gas recirculation valve more quickly after the on-vehicle engine is started. It is to provide a machine.

  An EGR valve warm-up device that solves the above problem is a device that warms up an EGR valve that adjusts the flow rate of EGR gas that is recirculated from an exhaust passage of an in-vehicle engine mounted on a vehicle to an intake passage, from a compressor to a condenser, The vehicle is provided with an air conditioning system having a refrigerant circuit in which the refrigerant circulates so as to return to the compressor through the evaporator in order. The EGR valve warm-up device branches from a refrigerant passage that connects the compressor and the condenser in the refrigerant circuit, and passes through the inside of the EGR valve and then rejoins the refrigerant passage, and the refrigerant flows in the branch passage. And a switching valve that switches between a state allowing the refrigerant and a state prohibiting the circulation of the refrigerant.

  In the refrigerant circuit, the refrigerant that has become hot due to compression by the compressor flows through the refrigerant passage between the compressor and the condenser. Therefore, if the switching valve is opened during the operation of the compressor, the high-temperature refrigerant flows through the branch passage branched from the refrigerant passage so that the EGR valve can be warmed up by the heat of the refrigerant. Become. The temperature of the refrigerant flowing through the refrigerant passage increases as soon as the compressor starts to be driven, regardless of the operation state of the on-vehicle engine after starting. Therefore, the time from the engine start to the completion of warming up of the EGR valve can be shortened.

1 is a schematic view schematically showing the configuration of an embodiment of a warm-up device for an exhaust gas recirculation valve. The flowchart of the EGR valve warming-up control routine which the control part provided in the warming-up apparatus of the embodiment implements. The time chart which shows transition of the refrigerant | coolant temperature at the time of engine starting in the same embodiment, a cooling water temperature, and EGR valve temperature.

Hereinafter, an embodiment of a warm-up device for an exhaust gas recirculation valve will be described in detail with reference to FIGS.
As shown in FIG. 1, the EGR valve 14 that warms up the warming-up device of the present embodiment is provided in an EGR passage 13 that connects an intake passage 11 and an exhaust passage 12 in an in-vehicle engine 10 mounted on a vehicle. ing. The EGR valve 14 adjusts the flow rate of exhaust gas (EGR gas) recirculated from the exhaust passage 12 to the intake passage 11 through the EGR passage 13 by changing the valve opening. The EGR valve 14 is closed after the start of the vehicle-mounted engine 10 until the temperature of the EGR valve 14 (hereinafter referred to as EGR valve temperature) reaches a prescribed EGR start temperature. When the EGR valve temperature reaches the EGR start temperature, the opening degree control of the EGR valve 14 is started so that an amount of EGR gas corresponding to the operation state of the on-vehicle engine 10 is introduced into the intake passage 11.

  Note that an engine cooling system that cools the in-vehicle engine 10 is mounted on a vehicle on which the warm-up device of the present embodiment is mounted. The engine cooling system includes a cooling water circuit 15 that circulates cooling water through the interior of the in-vehicle engine 10. The cooling water circuit 15 is provided with a water pump 16 that discharges the cooling water, and a radiator 17 that cools the cooling water by running air or air blown by an electric fan. And the cooling water circuit 15 is formed so that the cooling water discharged from the water pump 16 returns to the water pump 16 after passing through the inside of the vehicle-mounted engine 10 and the radiator 17 in order.

  A branch water channel 18 is branched from a portion of the cooling water circuit 15 between the in-vehicle engine 10 and the radiator 17. The branch water channel 18 passes through the inside of the EGR valve 14 and is in a portion between the cooling water circuit 15 and the radiator 17 of the in-vehicle engine 10, and is closer to the radiator 17 side than the branch position of the branch water channel 18. Thus, the cooling water circuit 15 is formed so as to merge again. Further, the branch water channel 18 is provided with a water stop valve 19 that permits the flow of the cooling water in the branch water channel 18 according to the valve opening and prohibits it according to the valve closing. Further, a water temperature sensor 20 that detects the temperature of the coolant that has passed through the interior of the in-vehicle engine 10 (hereinafter referred to as “cooling water temperature”) is provided in the vicinity of the coolant outlet of the in-vehicle engine 10 in the coolant circuit 15. It has been.

  Furthermore, the vehicle is equipped with an air conditioning system that adjusts the air temperature in the passenger compartment. The air conditioning system includes a refrigerant circuit 21 through which the refrigerant circulates from the compressor 22 through the condenser 23 and the evaporator 24 in order to return to the compressor 22.

  The air conditioning system realizes the following cooling cycle through the circulation of the refrigerant in the refrigerant circuit 21. That is, in the refrigerant circuit 21, the refrigerant flows into the compressor 22 as a low-temperature gas. Then, the refrigerant is sent to the condenser 23 as a high-temperature gas stored by compression in the compressor 22. The refrigerant that has become a high-temperature gas is cooled and liquefied in the condenser 23 by running wind or an electric fan. The liquefied refrigerant is depressurized at once in the evaporator 24 and vaporized. The refrigerant cools the air blown into the vehicle interior by the heat of vaporization at this time, and then returns to the compressor 22 as a low-temperature gas. In this air conditioning system, an electric compressor 22 is employed, and the above cooling cycle can be executed even when the in-vehicle engine 10 is not operating.

  The warming-up device of the present embodiment includes a branch passage 26 branched from a passage (hereinafter, referred to as a refrigerant passage 25) in a portion connecting the compressor 22 and the condenser 23 in the refrigerant circuit 21. The branch passage 26 is formed so as to merge with the refrigerant passage 25 again at a portion closer to the condenser 23 than the branch position of the branch passage 26 in the refrigerant passage 25 after passing through the inside of the EGR valve 14.

  In addition, the warm-up device of the present embodiment includes switching valves 27 and 28 that can switch between an operating position that allows the refrigerant to flow in the branch passage 26 and an operating position that prohibits the refrigerant from flowing. The switching valves 27 and 28 are provided at a branch position from the refrigerant passage 25 in the branch passage 26 and a joining position to the refrigerant passage 25 in the branch passage 26, respectively. In addition, switching of the operating positions of these two switching valves 27 and 28 is performed in conjunction with each other.

  Furthermore, the warm-up device of this embodiment includes an electronic control unit 30. The electronic control unit 30 is inputted with the cooling water temperature detected by the water temperature sensor 20 and the refrigerant temperature detected by the refrigerant temperature sensor 29. The electronic control unit 30 also receives an unlock signal that is a signal indicating that the door of the vehicle has been unlocked. Then, based on these inputs, the electronic control unit 30 drives the water stop valve 19, the compressor 22, and the switching valves 27 and 28, thereby promoting warm-up of the EGR valve 14 when the on-vehicle engine 10 is started. For warm-up control.

  The warm-up control routine of FIG. 2 shows the processing procedure of the electronic control unit 30 in such warm-up control of the EGR valve 14. The electronic control unit 30 starts the processing of this routine in response to the input of the unlocking signal, that is, when the vehicle door is unlocked.

  When the processing of this routine is started, the electronic control unit 30 first starts driving the compressor 22 in step S100, and in step S110, the electronic control unit 30 switches the switching valve 27 to the operating position that allows the refrigerant to flow in the branch passage 26. 28 operation positions are switched.

  Thereafter, when the in-vehicle engine 10 is not started until the predetermined time α has elapsed (S130: YES), the electronic control unit 30 stops driving the compressor 22 in step S160. Further, at this time, the electronic control unit 30 switches the operation position of the switching valves 27 and 28 to the operation position prohibiting the flow of the refrigerant in the branch passage 26 in step S170, and then ends the processing of this routine. To do.

  On the other hand, when the vehicle-mounted engine 10 is started before the predetermined time α has elapsed (S120: YES), the electronic control unit 30 drives and branches the compressor 22 until the cooling water temperature becomes higher than the refrigerant temperature. The circulation of the refrigerant in the passage 26 is continued. When the coolant temperature becomes higher than the coolant temperature (S140: YES), the electronic control unit 30 opens the water stop valve 19 and starts circulation of the coolant through the branch water channel 18. At this time, the electronic control unit 30 stops driving the compressor 22 in step S160, and switches the operating position of the switching valves 27 and 28 to an operating position in which the refrigerant flow in the branch passage 26 is prohibited in step S170. After that, the processing of this routine is terminated.

Then, the effect | action of the warming-up apparatus of the exhaust gas recirculation valve of this embodiment comprised as mentioned above and the effect produced by the effect | action are demonstrated.
FIG. 3 shows changes in the coolant temperature, the refrigerant temperature, and the EGR valve temperature when the EGR valve 14 is warmed up. In the figure, warming up of the EGR valve 14 is started from a state in which all of the cooling water temperature, the refrigerant temperature, and the EGR valve temperature are the same as the outside air temperature.

  In the figure, as a comparative example, the transition of the EGR valve temperature when the EGR valve 14 is warmed up using only cooling water is indicated by a broken line. When the vehicle-mounted engine 10 is started at time t2 in the figure, the cooling water temperature then rises. In the case of the comparative example, the EGR valve temperature rises following the rise in the cooling water temperature at this time. However, since it takes time to increase the coolant temperature after starting the in-vehicle engine 10, the EGR valve temperature reaches the EGR start temperature, and the EGR can be performed in the in-vehicle engine 10 from the start of the in-vehicle engine 10. It will be time t4 when a certain amount of time has passed.

  In contrast, in the case of the warming-up device of the present embodiment, when the vehicle door is unlocked at time t0 in the figure, the driving of the compressor 22 of the air conditioning system is started from that point. At this time, the operation positions of the switching valves 27 and 28 are switched to an operation position that allows the refrigerant to flow in the branch passage 26. As a result, the refrigerant compressed by the compressor 22 flows through the inside of the EGR valve 14. The temperature of the refrigerant flowing through the branch passage 26 at this time quickly rises after the compressor 22 starts to be driven. Then, the EGR valve temperature rises following the rise in the refrigerant temperature.

  Thus, in the case of this embodiment, the warm-up of the EGR valve 14 is started from the time when the occupant unlocks the door in order to get into the vehicle. In addition, the warm-up of the EGR valve 14 at this time is performed using a refrigerant that can be immediately heated, unlike the cooling water that takes time to raise the temperature. Therefore, the time from the start of the in-vehicle engine 10 to the completion of warming up of the EGR valve 14 is shortened as compared with the case of the comparative example. Incidentally, in the case of the figure, since the EGR valve temperature has reached the EGR start temperature at time t1 before the start of the in-vehicle engine 10, the EGR can be performed immediately after the in-vehicle engine 10 is started. Yes.

  Thereafter, the driving of the compressor 22 is stopped at the time t3 when the coolant temperature exceeds the refrigerant temperature after the vehicle-mounted engine 10 is started. At time t3, the operating positions of the switching valves 27 and 28 are switched to an operating position where the refrigerant flow in the branch passage 26 is prohibited in order to prepare for the subsequent use of cooling. At this time, the warm-up of the EGR valve 14 by the refrigerant is finished, and thereafter, the EGR valve 14 is kept warm by the cooling water flowing through the branch water channel 18. That is, the EGR valve temperature was kept within an appropriate range through heat exchange with the cooling water with respect to the cooling of the EGR valve 14 by the low temperature outside air and the heating of the EGR valve 14 by the heat of the EGR gas during the EGR operation. It is.

  Incidentally, when the door is unlocked for the purpose other than starting the vehicle-mounted engine 10 and running the vehicle, the EGR valve 14 is warmed up by the refrigerant when the elapsed time after unlocking reaches a specified time α. Will be terminated.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the warm-up of the EGR valve 14 by the refrigerant is started according to the unlocking of the door, but the warm-up may be started at other timing. For example, it is possible to configure the warm-up device so that the warm-up of the EGR valve 14 by the refrigerant is started from the start of the vehicle-mounted engine 10. Also in this case, since the temperature of the refrigerant rises more quickly than the cooling water, the time from the start of the in-vehicle engine 10 to the completion of warming up of the EGR valve 14 is shortened.

  In the above embodiment, when the cooling water temperature becomes higher than the refrigerant temperature, the warm-up (warming) of the EGR valve 14 by the coolant is switched from the warm-up of the EGR valve 14 by the coolant. On the other hand, you may make it continue the warming-up (warming) of the EGR valve 14 by a refrigerant | coolant after that. If the EGR valve 14 is not warmed up (insulated) by the cooling water, the branch water channel 18 and the water stop valve 19 can be omitted.

  DESCRIPTION OF SYMBOLS 10 ... Engine mounted, 11 ... Intake passage, 12 ... Exhaust passage, 13 ... EGR passage, 14 ... EGR valve (exhaust gas recirculation valve), 21 ... Refrigerant circuit, 22 ... Compressor, 23 ... Condenser, 24 ... Evaporator, 25 ... Refrigerant passage (connecting compressor and condenser), 26 ... branch passage, 27, 28 ... switching valve.

Claims (1)

A warming-up device that warms up an exhaust gas recirculation valve that adjusts a flow rate of exhaust gas that is recirculated from an exhaust passage of an in-vehicle engine mounted on a vehicle to an intake passage,
The vehicle is equipped with an air conditioning system having a refrigerant circuit in which refrigerant circulates so as to return to the compressor through a condenser, an evaporator, and the compressor in order.
And the warm-up device is
A branch passage branching from a refrigerant passage connecting the compressor and the condenser in the refrigerant circuit and rejoining the refrigerant passage after passing through the exhaust recirculation valve;
A switching valve that switches between a state of allowing the refrigerant to flow in the branch passage and a state of prohibiting the flow of the refrigerant;
An exhaust gas recirculation valve warm-up device.

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