JP6432445B2 - Condensate drain device - Google Patents

Description

  The present invention relates to a condensed water discharge device applied to a hybrid vehicle using an internal combustion engine and an electric motor as a driving source for traveling.

  In the exhaust passage of the internal combustion engine, condensed water may be generated due to moisture in the fuel. Condensed water is generated in the process of cooling the exhaust gas from the internal combustion engine. Therefore, the condensate is generated not only when the exhaust passage is not sufficiently warmed as in cold start, but also when exhaust heat is This can also be conspicuous when an exhaust heat recovery device for use in a machine is provided in the exhaust passage. Since this condensed water may cause abnormal noise due to water flow, blockage of the exhaust passage due to freezing, and corrosion of each part of the exhaust passage, it is desirable to discharge this condensed water.

  For example, in the apparatus disclosed in Patent Document 1, in a vehicle in which an exhaust heat recovery device is provided in an exhaust passage of an internal combustion engine, a drain valve is installed in the exhaust passage for discharging condensed water. By opening the drain valve, the inside and outside of the exhaust passage communicate with each other, and condensed water is discharged. In this apparatus, in order to suppress the dirt on the road surface of the parking place due to the discharged condensed water, the condensed water is discharged only when the vehicle is traveling at the reference vehicle speed or higher. This is because when the condensed water discharged is collected on the ground, it becomes easy to collect dust, and the collected dust is difficult to be washed away by wind and rain in a site with a roof or in a parking lot.

JP 2009-13810 A

  However, if the drain valve provided in the exhaust passage is opened, the exhaust gas is also discharged from the exhaust passage together with the condensed water, so that the exhaust gas may enter the vehicle interior. In general, condensed water can be evaporated and removed as the exhaust passage continues to be hot. However, in a hybrid vehicle, the continuous operation time of the internal combustion engine tends to be shorter, so that compared to a vehicle driven only by the internal combustion engine. Thus, condensed water can be a bigger problem.

  In view of the above points, the present invention provides a condensate discharge device that can suppress the intrusion of exhaust gas into the passenger compartment due to the discharge of condensate while suppressing dirt on the road surface due to the discharged condensate. For the purpose.

In order to achieve the above object, the condensed water discharge apparatus according to the present invention is:
A condensed water discharger applied to a hybrid vehicle having an internal combustion engine and an electric motor as a driving source for traveling,
A drain valve provided in the exhaust passage of the internal combustion engine and configured to discharge condensed water staying in the exhaust passage;
A control unit for controlling the drain valve,
The control unit is configured to open the drain valve when the internal combustion engine is stopped and the hybrid vehicle is running with the electric motor as a drive source.

  In the present invention, the control unit opens the drain valve when the internal combustion engine is stopped and the vehicle is running with the electric motor as a drive source. Since the condensed water is discharged only when the vehicle is running, it is possible to suppress the dirt on the road surface of the parking place. In addition, since the condensed water is discharged only when the internal combustion engine is stopped, the exhaust gas discharge due to the condensed water discharge can be suppressed, thereby suppressing the intrusion of the exhaust gas into the vehicle interior. be able to.

1 is a block diagram showing a schematic configuration of a hybrid vehicle according to a first embodiment of the present invention. It is a side view showing a schematic structure of an exhaust passage of a hybrid vehicle concerning a 1st embodiment. It is a side view which shows the exhaust heat recovery device in 1st Embodiment. It is a side view which shows the muffler in 1st Embodiment. It is a flowchart which shows the flow of the condensed water discharge control in 1st Embodiment. It is a side view which shows the exhaust heat recovery device in 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a hybrid vehicle 10 to which the present invention is applied. The hybrid vehicle 10 includes an engine 12 that is an internal combustion engine and a vehicle drive motor 14 that is a three-phase synchronous rotating electric machine as driving sources for traveling. The hybrid vehicle 10 also includes a generator 16 that is a three-phase synchronous rotating electrical machine that generates electric power upon receiving a driving force.

  The engine 12, the vehicle drive motor 14, and the generator 16 are connected to each other via a power split mechanism 18. A reduction gear 20 is connected to the rotating shaft of the vehicle drive motor 14 connected to the power split mechanism 18. The speed reducer 20 connects the rotation shaft of the motor 14 and the drive shaft 24 connected to the drive wheels 22. The power split mechanism 18 splits the driving force of the engine 12 into the generator 16 side and the speed reducer 20 side. The distribution of the driving force by the power split mechanism 18 can be arbitrarily changed.

  Hybrid vehicle 10 further includes an inverter 26, a converter 28, and a high voltage battery 30. Inverter 26 is connected to generator 16 and vehicle drive motor 14, and is also connected to high voltage battery 30 via converter 28. The electric power generated by the generator 16 can be supplied to the vehicle drive motor 14 via the inverter 26, or the high voltage battery 30 can be charged via the inverter 26 and the converter 28. Further, the electric power charged in the high voltage battery 30 can be supplied to the vehicle drive motor 14 via the converter 28 and the inverter 26.

  In the hybrid vehicle 10, the vehicle driving motor 14 can be stopped and the driving wheel 22 can be rotated only by the driving force of the engine 12. Conversely, the engine 12 is stopped and the driving force of the vehicle driving motor 14 is stopped. The drive wheel 22 can also be rotated only by the above. Furthermore, both the vehicle drive motor 14 and the engine 12 can be operated, and the drive wheels 22 can be rotated by both drive forces. In the hybrid vehicle 10, the vehicle driving motor 14 can also function as a starter for the engine 12. That is, when the engine 12 is started, the engine 12 can be cranked by inputting part or all of the driving force of the vehicle drive motor 14 to the engine 12 via the power split mechanism 18.

  The hybrid vehicle 10 further includes a car navigation system 41. The car navigation system 41 detects a traveling direction of the vehicle 10 in addition to a navigation processing unit that performs calculations based on various input signals, a GPS receiver that receives radio waves from artificial satellites, a map database in which map information is recorded. A gyro sensor, a display unit, an audio output unit, and an operation unit are included. In the map database, information indicating a drainage prohibited area where the discharge of condensed water is prohibited is input in advance. In the present embodiment, a parking lot with a roof, a multi-story parking lot, and other places where it is difficult to discharge condensed water are previously input into the map database as drainage prohibited areas. Condensed water that has been discharged easily collects dust when it accumulates on the ground, and the collected dust is difficult to be washed away by wind and rain in roofed sites and parking lots. It is desirable. This drainage prohibited area may be designated by a user input operation.

  FIG. 2 is a side view showing the configuration of the exhaust passage 48 from the engine 12. An exhaust manifold 42, a catalyst device 43, an exhaust heat recovery device 44, a sub muffler 45, and a main muffler 46 are connected to the exhaust port of the engine 12 in order from the upstream side by an exhaust pipe 47. Is configured. The catalyst device 43 includes, for example, an oxidation catalyst and a three-way catalyst. The exhaust heat recovery unit 44 recovers exhaust heat of the exhaust gas from the exhaust system of the engine 12 and uses this exhaust heat for promoting warm-up of the engine 12 and the like.

  As shown in FIG. 3, the exhaust heat recovery device 44 has cooling blocks 51 and 52 for circulating cooling water held inside a substantially cylindrical case 53. The cooling blocks 51 and 52 are both generally cylindrical and have a hollow inside, and are concentric with each other. The case 53 is formed by fixing a front case 53a integrated with an inlet pipe 56 into which exhaust gas is introduced and a rear case 53b integrated with an outlet pipe 57 through which exhaust gas is discharged.

  At the downstream end of the inlet pipe 56, an intermediate pipe 58 is fixed via a spacer 59, and the intermediate pipe 58 has a number of low-flow passages 58a serving as through holes. The downstream end of the cooling block 52 is closed by an annular closing plate 52a. Exhaust gas flowing in from the inlet pipe 56 flows to a region outside the intermediate pipe through the low flow passage 58 a and the space between the inlet pipe 56 and the intermediate pipe 58, and reaches the upstream end of the cooling block 52. It flows in the space between the cooling blocks 51 and 52 toward the downstream side via the vicinity.

  A movable lid 62 is turnably supported at the downstream end of the intermediate pipe 58 via a support piece 60 and a shaft 61. The movable lid 62 is always urged by a spring (not shown) in the direction to close the downstream end of the intermediate pipe 58, and when the flow rate of the exhaust gas exceeds a predetermined value, the exhaust pressure causes an arrow a in the figure. Turn in the direction. When the movable lid 62 is open, the exhaust gas is discharged straight from the intermediate pipe 58 toward the downstream side.

  A water supply pipe 54 and a water discharge pipe 55 are connected to the cooling blocks 51 and 52, respectively. The water supply pipe 54 is connected to the cooling blocks 51 and 52 on the upper side of the exhaust heat recovery unit 44, and the water discharge pipe 55 is connected to the lower side of the exhaust heat recovery unit 44, respectively. The water supply pipe 54 and the water discharge pipe 55 are connected to a water jacket (not shown) of the engine 12. The water supply pipe 54 is connected to a discharge side of a water pump (not shown) for cooling the engine by branching from a cooling water passage to a radiator (not shown), and the cooling water discharged from the water pump is The water is supplied to the cooling blocks 51 and 52 via the water supply pipe 54, and the exhaust heat is recovered and returned to the engine 12.

  As shown in FIG. 4, the main muffler 46 includes an inlet pipe 74 and an outlet pipe 75 arranged through partition plates 72 and 73 provided inside the case 71. A cylindrical diffuser 76 is fixed to the outlet pipe 75. The purpose of providing the diffuser 76 is to reduce exhaust noise, to reduce exhaust gas temperature and exhaust pipe temperature in a place accessible from the outside, and to improve design.

  A lower part 77 for capturing condensed water is formed at the lowermost part of the case 71 of the main muffler 46. The condensed water generated in the case 71 flows into the lower portion 77 by its own weight. A drain pipe 78 that leads to the outside of the case 71 is provided along the bottom surface of the downstream end of the lower portion 77, and a drain valve 79 for opening and closing the drain pipe 78 is provided. The drain valve 79 is, for example, a butterfly valve. The rear end portion of the drain pipe 78 is open toward the inside of the diffuser 76. The drain valve 79 is opened and closed by a drain valve actuator 80 made of, for example, a motor. The drain valve 79 is normally closed. That is, the inside of the main muffler 46 is not communicated with the outside during normal times. The rear end portion of the drainage pipe 78 that is a drainage point in the present embodiment is located behind the passenger compartment.

  The hybrid vehicle 10 of this embodiment is controlled by an ECU (Electronic Control Unit) 40 as a control unit in the present invention. The ECU 40 is a well-known digital computer and includes a CPU, ROM, RAM, D / A converter, A / D converter, and the like (not shown). The ECU 40 includes an accelerator opening sensor 91 provided in the vicinity of an unillustrated accelerator pedal, a vehicle speed sensor 92 provided in the vicinity of the drive wheel 22, and a state of charge (State of charge; SOC) of the high-voltage battery 30. An SOC sensor 93 to be detected is connected. The SOC sensor 93 includes a current sensor, a voltage sensor, and a temperature sensor, and acquires the SOC of the high voltage battery 30 using the current, voltage, and temperature of the high voltage battery 30. The SOC is an index indicated by a charging rate of the high voltage battery 30 when the high voltage battery 30 is fully charged and 100%, and when the battery is empty is 0%. The ECU 40 is further connected to a drain valve actuator 80 for driving the drain valve 79 (FIGS. 2 and 4). The ECU 40 is further connected to a water temperature sensor 94 that detects the cooling water temperature of the engine, an outside air temperature sensor 95 that detects outside air temperature, and an outside air humidity sensor 96 that detects outside air humidity.

  The ECU 40 comprehensively controls the entire hybrid vehicle 10 including the engine 12, the vehicle drive motor 14, the generator 16, the power split mechanism 18, the inverter 26, the converter 28, and the like as drive control for traveling. . This drive control is basically executed based on detection values of the accelerator opening sensor 91, the vehicle speed sensor 92, and the SOC sensor 93. The car navigation system 41 outputs the current position information of the vehicle 10 and information indicating the drainage prohibited area in response to a request from the ECU 40. The ECU 40 is further configured to control the drain valve actuator 80 based on the operating state of the vehicle 10 and information from the car navigation system 41.

  Control of the condensed water discharge device of the present embodiment configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing a flow of condensate discharge control performed by the CPU of the ECU 40 in accordance with a control program stored in the ROM or the like. This control is executed when the ignition switch of the vehicle 10 is turned on.

  First, the ECU 40 reads each parameter indicating the driving state of the vehicle 10 (S10). Here, the information read by the ECU 40 includes the current position information from the car navigation system 41, the information indicating the drainage prohibition area, the information from the various sensors 91 to 96, the engine 12 in the drive control executed by the ECU 40 itself, the vehicle It includes information on control states of the drive motor 14, the generator 16, the power split mechanism 18, the inverter 26, the converter 28, and the like.

  Next, the ECU 40 determines whether the vehicle 10 is traveling by the vehicle driving motor 14 (S20). If the vehicle is not traveling by the vehicle drive motor 14, for example, if the vehicle is stopped or the engine 12 is traveling, the result in Step S20 is negative.

  If the determination in step S20 is affirmative, that is, if the vehicle is running by the vehicle drive motor 14, then the ECU 40 determines whether the vehicle speed is equal to or higher than a predetermined value Vth (S30). Here, the predetermined value Vth is a value larger than 0 km / h, and is, for example, a value (5 km / h in the present embodiment) that can be regarded as the vehicle 10 traveling when the vehicle speed is equal to or higher than this value. Can be set. If the vehicle speed is less than the predetermined value Vth, the result in Step S30 is negative.

  If the determination in step S30 is affirmative, that is, if the vehicle speed is equal to or higher than the predetermined value Vth, then the ECU 40 determines whether the engine 12 is stopped (S40). If the engine 12 is not stopped, a negative result is obtained in step S40.

  If the determination in step S40 is affirmative, that is, if the engine 12 is stopped, the ECU 40 next determines whether or not the current position of the vehicle 10 is outside the drainage prohibited area (S50). If it is in the drainage prohibited area, the result in Step S50 is negative.

  If the determination in step S50 is affirmative, that is, if it is outside the drainage prohibited area, the ECU 40 next determines whether the estimated amount of condensed water in the main muffler 46 is equal to or greater than a predetermined value Cth (S60). The estimated amount of condensed water is, for example, the operation time of the engine 12 within a predetermined time after the cold start, the engine water temperature, the outside air temperature, the outside air humidity, the operation time after the engine 12 is warmed up, and the elapsed time from the end of the operation after the warm up. Can be calculated by a predetermined function. If the estimated amount of condensed water is less than the predetermined value Cth, the result in Step S60 is negative.

  If the determination in step S60 is affirmative, that is, if the estimated amount of condensed water is equal to or greater than the predetermined value Cth, then the ECU 40 determines whether the opening time of the drain valve 79 is equal to or greater than the predetermined value Tth (S70). The predetermined value Tth is set to a time sufficient for discharging condensed water of the predetermined value Cth after the drain valve 79 is opened. In the initial state, since the drain valve 79 is not yet opened, the result in Step S70 is negative.

  If NO in step S70, that is, if the estimated amount of condensed water is greater than or equal to the predetermined value Cth, the ECU 40 next outputs an opening instruction to the drain valve actuator 80 (S80). Accordingly, the drain valve 79 is opened when it is closed, and is kept open when it is open. As a result, the inside and the outside of the main muffler 46 are in communication with each other, so that the condensed water staying in the main muffler 46 is discharged to the outside. Next, the ECU 40 increments an open time counter indicating the duration of the drain valve 79 in the open state (S90), and the process is returned.

  If the result is negative in any of steps S20 to S60 or affirmative in step S70, the process proceeds to step S100, and the ECU 40 outputs a closing instruction to the drain valve actuator 80. Accordingly, the drain valve 79 is closed when it is open, and is kept closed when it is closed. Finally, the ECU 40 resets the opening time counter to 0 (S110), and the process is returned.

  As a result of the above processing, in the present embodiment, the drain valve 79 is opened only when the engine 12 is stopped (S40) and the vehicle 10 is running by the vehicle drive motor 14 (S20). Will be. Therefore, in the present embodiment, since the condensed water is discharged only when the vehicle 10 is traveling, the dirt on the road surface due to the discharged condensed water can be suppressed. Further, since the condensed water is discharged only when the engine 12 is stopped, it is possible to suppress the exhaust gas discharge due to the condensed water discharge, thereby suppressing the intrusion of the exhaust gas into the vehicle interior. be able to.

  Moreover, in this embodiment, drainage of condensed water is performed only when the vehicle 10 is outside the drainage prohibition area (S50), so drainage within the drainage prohibition area can be effectively avoided.

  Further, in the present embodiment, since the condensed water is discharged into the diffuser 76, the condensed water can be effectively atomized or diffused using the pressure of the exhaust gas discharged from the outlet pipe 75.

  In the present embodiment, the low temperature portion 77 is provided with an electric heating heater for freezing, and the ignition of the vehicle 10 is performed when the outside temperature is below freezing and the standing time is not less than a predetermined value and the estimated amount of condensed water is not less than the predetermined value. The heater may be activated simultaneously with the switch being turned on. The opening of the exhaust valve 79 may be permitted on the condition that a sufficient time has elapsed since the start of energization of the heater to melt the condensed water of the estimated amount of condensed water.

  Further, in the present embodiment, the drain valve 79 is configured to be closed when the engine 12 is in operation (S40 / S100), but if the start condition is satisfied even before the engine 12 is started, The drain valve 79 may be configured to be closed. In this case, the drain valve 79 can be reliably closed before the engine 12 is started.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. The drain valve in the present invention can be provided at any position in the exhaust passage. In the second embodiment, the exhaust heat recovery device 44 in the first embodiment is provided with a drain valve 179 for discharging condensed water.

  As shown in FIG. 6, a trapping chamber 176 including a lower portion 177 for trapping condensed water is formed at the lowermost portion of the case 53 of the exhaust heat recovery device 44. The condensed water generated in the case 53 flows into the lower portion 177 by its own weight. A drain pipe 178 that leads to the outside of the case 53 is provided along the bottom surface of the downstream end of the lower portion 177, and the drain valve 179 selectively closes or opens between the capture chamber 176 and the drain pipe 178. Is configured to do. The drain valve 179 includes a valve body 170, a valve shaft 171 and a spring 172, and is opened and closed by a drain valve actuator 180 made of, for example, a solenoid. The valve body 170 is always urged in the closing direction by the spring 172, so that the drain valve 179 maintains a closed state during normal times. In other words, the inside and outside of the exhaust heat recovery device 44 are not communicated with each other at normal times.

  The structure of the remaining part of 2nd Embodiment is the same as that of the said 1st Embodiment, About the part similar to the said 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. In the second embodiment, the main muffler 46 is not provided with the discharge valve 79, but the discharge valve 79 may be provided.

  In the second embodiment configured as described above, the condensed water discharge control in the first embodiment can be applied as it is. That is, the output made to the drain valve actuator 80 in the condensed water discharge control of FIG. 5 in the first embodiment can be directly applied to the drain valve actuator 180 in the second embodiment. In the second embodiment, the same effects as in the first embodiment can be obtained for the condensed water in the exhaust heat recovery unit 44. In particular, in the second embodiment, even if the drain pipe 178 of the exhaust heat recovery device 44, which is a drain point, is located directly under the vehicle compartment or in front of the vehicle compartment, the exhaust gas into the vehicle compartment accompanying the discharge of condensed water This is advantageous because it is possible to suitably suppress the intrusion. However, the present invention is also suitable for cases other than the case where the drainage point is directly below the vehicle compartment or in front of the vehicle compartment (that is, the case where the drainage point is behind the vehicle compartment as in the first embodiment). Can be applied.

  Further, in the second embodiment, since the capture chamber 176 that isolates the condensed water from the main flow of the exhaust gas is provided, it is possible to improve the drainage of the condensed water, the pressure loss due to the narrowing of the inlet of the capture chamber 176, and the condensed water Due to the barrier property, exhaust gas exhaust through the drain pipe 178 can be suppressed, and the condensed water trapped inside the trapping chamber 176 can be cooled by being isolated from the main stream of the exhaust gas. Concentration due to re-evaporation of condensed water on a wide range of wall surfaces in the exhaust passage outside 176 can be suppressed.

  The present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

12 Engine 14 Vehicle drive motor 44 Exhaust heat recovery unit 46 Main muffler 48 Exhaust passage 79, 179 Drain valve 80, 180 Drain valve actuator

Claims (2)

A condensed water discharger applied to a hybrid vehicle having an internal combustion engine and an electric motor as a driving source for traveling,
A drain valve provided in the exhaust passage of the internal combustion engine and configured to discharge condensed water staying in the exhaust passage;
A control unit for controlling the drain valve,
The control unit is configured to open the drain valve only when the internal combustion engine is stopped and the hybrid vehicle is running using the electric motor ,
Condensed water discharge is performed only when the hybrid vehicle travels while the internal combustion engine is stopped . The condensate drain device according to claim 1, wherein the control unit is configured not to open the drain valve in a preset drainage prohibition area of the condensate.