JP2015190390A - Engine intake air cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve power performance of an engine without deteriorating fuel economy by a simple configuration.SOLUTION: An engine intake air cooling structure includes: an evaporator 11 incorporated in an on-board air conditioner 1 to cool air to be supplied into a vehicle interior; a drain pipe 2 for draining condensed water 7 generated in the evaporator 11 to the outside of the vehicle; and a cool air pipe 4 branching from the drain pipe 2 and connected to an air cleaner 5 constituting an engine air intake system to guide the cool air inside the drain pipe 2 to the air cleaner 5.

Description

  The present invention relates to an intake air cooling structure for an engine that uses an in-vehicle air conditioner to reduce the intake air temperature of the engine.

Generally, an air conditioner (vehicle-mounted air conditioner) for air-conditioning the vehicle interior is mounted on the vehicle. The vehicle-mounted air conditioner includes a condenser (compressor) and an evaporator (evaporator), and performs a cooling operation while circulating refrigerant between them to repeat heat absorption and heat dissipation.
Usually, a condenser provided in an in-vehicle air conditioner is driven by engine power. For this reason, when the vehicle-mounted air conditioner starts the cooling operation, the engine load increases and the engine power performance (engine speed and output torque) decreases. In order to recover this, the amount of air supplied to the engine and the amount of fuel injection must be increased, and the amount of energy consumption increases, leading to deterioration of fuel consumption.

  Conventionally, it has been proposed to increase the engine output by increasing the charging efficiency and volumetric efficiency by lowering the intake air temperature of the engine in order to solve such a problem. For example, there has been proposed a technique for lowering the intake air temperature by introducing a part of the cooling air supplied from the in-vehicle air conditioner toward the vehicle interior into the intake system of the engine (see Patent Documents 1 and 2). In addition, a technique for lowering the intake air temperature by directing the drainage of the in-vehicle air conditioner directly to the outer peripheral surface of the intake pipe has been proposed (see Patent Document 3).

Japanese Unexamined Patent Publication No. 4-334752 Japanese Patent Laid-Open No. 2003-247466 Japanese Unexamined Patent Publication No. Hei 4-21418

However, in the techniques described in Patent Documents 1 and 2, since the cooling air that should be supplied into the vehicle interior is turned to the engine side, the temperature in the vehicle interior rises instead of the intake air temperature decreasing. End up. In order to keep the temperature in the passenger compartment constant, the output of the in-vehicle air conditioner must be increased, which increases the air conditioning load.
On the other hand, in the technique described in Patent Document 3, although the temperature in the passenger compartment and the air conditioning load do not change, the structure for circulating the drainage around the intake pipe becomes complicated. Moreover, since drainage is always supplied around the intake pipe during cooling operation, there is a risk of rusting. As a result, the intake pipe must be manufactured in a complicated shape with a material having high corrosion resistance, which increases the manufacturing cost and the weight of the member, and thus is practically difficult to apply.

  One of the purposes of this case was created in view of the above-mentioned problems, and has a simple configuration and can improve engine power performance without deteriorating fuel consumption. It is to provide a cooling structure. The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) An engine intake air cooling structure disclosed herein includes an evaporator that cools air supplied to a vehicle interior, and a drain pipe that discharges condensed water generated in the evaporator to the outside of the vehicle. And a cold air pipe that branches from the drain pipe and is connected to an intake system of an engine and guides cool air in the drain pipe to the intake system.
In addition, it is preferable to interpose a three-way branch pipe at a branch point between the drain pipe and the cold air pipe. Thereby, a cold air pipe can be easily branched from the existing drain pipe.

(2) Preferably, the drain pipe extends downward from a branch point with the cold air pipe, and the cold air pipe extends upward from a branch point with the drain pipe.
(3) It is preferable that the cold air pipe is connected to an upstream side of a filter of an air cleaner constituting the intake system.

  According to the disclosed intake air cooling structure of the engine, since the cool air pipe that guides the cool air in the drain pipe to the intake system of the engine is provided, the cool air in the drain pipe that has been exhausted conventionally is used to reduce the intake air temperature of the engine. The engine power performance can be enhanced without deteriorating fuel consumption. Further, since it is only necessary to connect the drain pipe and the intake system with a cold air pipe, a simple configuration can be achieved.

It is a perspective view which illustrates the whole intake-air cooling structure of the engine concerning one embodiment. It is a schematic diagram which illustrates the branch location in the intake air cooling structure of the engine of FIG.

  An engine intake air cooling structure as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment, and can be selected as necessary or combined as appropriate.

[1. Constitution]
[1-1. overall structure]
The intake air cooling structure of the engine of this embodiment is applied to the engine 6 illustrated in FIG. The engine 6 is mounted on a vehicle and generates power in the vehicle by burning fuel and air inside. The power generated by the engine 6 is mainly used to drive the vehicle, but is also used to drive an HVAC (Heater, Ventilator and Air Conditioner) that adjusts the temperature and humidity in the vehicle cabin. Is done.
In FIG. 1, main components of the intake air cooling structure for the engine of the present embodiment are indicated by solid lines, and other components are indicated by broken lines.

The HVAC 1 is for adjusting the air-conditioning environment in the passenger compartment, and is disposed adjacent to the engine 6 inside the engine room of the vehicle. The HVAC 1 includes an evaporator (evaporator) 11, a heater and a fan (not shown), and the like.
The evaporator 11 absorbs heat by depressurizing and evaporating the refrigerant, and functions as a cooling device for the HVAC 1. That is, the evaporator 11 cools the air supplied into the vehicle compartment during the cooling operation of the HVAC 1.
In the vicinity of the evaporator 11, a drain pipe 2 for discharging condensed water 7 generated in the evaporator 11 to the outside of the vehicle is disposed. Here, the drain pipe 2 extends from the case bottom surface portion 12 of the HVAC 1 toward the outside of the vehicle.

An air cleaner 5 is disposed above the engine 6. The air cleaner 5 is connected to an intake system of the engine 6 through a connection duct 51 and is connected to an intake duct 52 that opens toward the outside of the vehicle, and dust and moisture are supplied from the intake air supplied to the engine 6 from the outside of the vehicle. It is for removing.
Inside the air cleaner 5, a filter 53 is provided so as to cross the intake air flow path. The filter 53 collects and removes dust and moisture contained in the air passing therethrough, and is interposed between the connection duct 51 and the intake duct 52.

Note that the air cleaner 5, the connection duct 51 and the intake duct 52 all constitute an intake system of the engine 6. That is, the filter 53 described above is interposed in the intake system of the engine 6.
The air cleaner 5 is provided with a cold air port 54 for connecting the cold air pipe 4 branched from the drain pipe 2 to the intake system of the engine 6. The cold air port 54 is formed so as to penetrate the case upper surface portion 55 of the air cleaner 5 on the upstream side of the filter 53 with reference to the flow direction of the intake air.

  The engine intake cooling structure of the present embodiment includes an evaporator 11, a drain pipe 2, and a cold air pipe 4. Here, a three-way branch pipe 3 which is a member for branching the cold air pipe 4 from the drain pipe 2 and separating the condensed water 7 and the cold air is interposed at a branch point P between the drain pipe 2 and the cold air pipe 4. Yes. Hereinafter, each configuration will be described in the order of the three-way branch pipe 3, the drain pipe 2, and the cold air pipe 4.

[1-2. Three-way branch pipe]
As shown in FIG. 2, the three-way branch pipe 3 includes three pipe portions 31, 32, and 33 that extend linearly from the base point in different directions. Each of the pipe portions 31, 32, 33 is formed in a tubular shape having a circular closed cross section with the same cross section.

  Hereinafter, the pipe parts 31, 32, and 33 are referred to as a first pipe part 31, a second pipe part 32, and a third pipe part 33, respectively. The first pipe part 31 and the third pipe part 33 constitute a part of the drain pipe 2, and the second pipe part 32 constitutes a part of the cold air pipe 4 branched from the drain pipe 2. is there. That is, the base point of the three-way branch pipe 3 corresponds to the center point of the branch point P between the drain pipe 2 and the cold air pipe 4.

  Here, the second pipe part 32 and the third pipe part 33 are extended on the same straight line so as to extend in opposite directions. In other words, the portion constituted by the third pipe portion 33 of the drain pipe 2 and the portion constituted by the second pipe portion 32 of the cold air pipe 4 are arranged in a straight line with the branch point P interposed therebetween. On the other hand, the first pipe portion 31 extends in a direction perpendicular to the extending direction of the second pipe portion 32 and the third pipe portion 33.

[1-3. Drain pipe]
As shown in FIG. 1, the drain pipe 2 forms a flow path of condensed water 7 from the evaporator 11 toward the outside of the vehicle. Here, the drain pipe 2 is composed of two members, an upstream pipe 21 provided on the upstream side (the evaporator 11 side) and a three-way branch pipe 3 provided on the downstream side of the upstream pipe 21 on the basis of the flow direction of the condensed water 7. It is configured.

  As shown in FIG. 2, the upstream pipe 21 is formed to have a circular closed cross section with a substantially uniform cross section, and the inner diameter thereof is large enough to fit the outer diameter of the first pipe portion 31 of the three-way branch pipe 3. It is assumed. An upstream end 21 a of the upstream pipe 21 is connected to a drain port 12 a formed in the case bottom surface portion 12 of the HVAC 1. Further, the downstream end 21 b of the upstream pipe 21 is disposed below the upstream end 21 a and is connected to the first pipe portion 31 of the three-way branch pipe 3. The drain port 12a is provided beside the evaporator 11.

The downstream end portion 21b of the upstream pipe 21 and the first pipe portion 31 fitted in the upstream pipe 21 are arranged in an inclined state with the branch point P side positioned downward. Further, along with this, the third pipe portion 33 is arranged in an inclined state with the branch point P side positioned upward. In other words, the portion constituted by the third pipe portion 33 of the drain pipe 2 extends downward from the branch point P.
A portion between the upstream end 21a and the downstream end 21b of the upstream pipe 21 is appropriately shaped and arranged so as not to interfere with the shape and arrangement of peripheral members such as the engine 6 and the HVAC 1. . However, from the viewpoint of smoothly discharging the condensed water 7 toward the outside of the vehicle, the upstream pipe 21 is extended so as to be always directed downward toward the downstream side.

[1-4. Cold air pipe]
As shown in FIG. 1, the cold air pipe 4 branches from the drain pipe 2 and is connected to the intake system of the engine 6, and guides the cold air in the drain pipe 2 to the intake system of the engine 6. Here, the cold air pipe 4 is composed of two members, a three-way branch pipe 3 provided on the upstream side (branch point P side) and a downstream pipe 41 provided on the downstream side of the three-way branch pipe 3 on the basis of the flow direction of the cold air. It is configured.

  As shown in FIG. 2, the downstream pipe 41 is formed to have a circular closed cross section with a substantially uniform cross section, and the inner diameter thereof is large enough to fit the outer diameter of the second pipe portion 32 of the three-way branch pipe 3. It is assumed. The downstream end 41 b of the downstream pipe 41 is connected to a cold air port 54 provided in the case upper surface portion 55 of the air cleaner 5. The upstream end 41 a of the downstream pipe 41 is connected to the second pipe part 32 of the three-way branch pipe 3.

The upstream end portion 41a of the downstream pipe 41 and the second pipe portion 32 fitted into the downstream tube 41 are arranged in a state where the branch point P side is positioned downward. That is, the portion constituted by the second pipe portion 32 of the cold air pipe 4 extends upward from the branch point P.
The portion between the upstream end 41a and the downstream end 41b of the downstream pipe 41 has an appropriate shape and arrangement so as not to interfere with the peripheral members such as the engine 6 and the HVAC 1 according to the arrangement and shape of the peripheral members. Is done.

[2. Action]
Hereinafter, the operation according to the intake air cooling structure of the engine of this embodiment will be described.
When the evaporator 11 is driven during the cooling operation of the HVAC 1, the surface temperature of the evaporator 11 decreases. As a result, condensation occurs on the surface of the evaporator 11, and the low-temperature condensed water 7 adheres. When the amount of the condensed water 7 increases, the condensed water 7 drops from the surface of the evaporator 11 onto the case bottom surface portion 12. And the condensed water 7 collected on the case bottom face part 12 flows out into the drain pipe 2 from the drain port 12a. At this time, a part of the air (cold air) cooled by the evaporator 11 together with the condensed water 7 flows into the drain pipe 2 from the HVAC 1 through the drain port 12a. Therefore, the air in the drain pipe 2 is always cooled by the condensed water 7 and cold air.

  The condensed water 7 flows downward in the upstream pipe 21 of the drain pipe 2 by the action of gravity, and flows into the first pipe portion 31 of the three-way branch pipe 3 continuous with the upstream pipe 21. On the other hand, the cooled air (cold air) in the drain pipe 2 is cooled by the differential pressure (intake negative pressure) between the pressure in the drain pipe 2 (external pressure) and the intake pressure of the engine 6 (cold air pressure). Inhaled into the trachea 4 side). That is, the cold air is pulled by the intake negative pressure of the engine 6, flows down through the upstream pipe 21 of the drain pipe 2, and flows into the three-way branch pipe 3 like the condensed water 7.

When the condensed water 7 reaches the branch point P, the condensed water 7 flows downward by its own weight and flows into the third pipe portion 33 (see the hatched arrow in FIG. 2). Then, it is discharged out of the vehicle through the third pipe portion 33.
On the other hand, when the cold air reaches the branch point P, the cold air is sucked into the low-pressure engine 6 by the intake negative pressure and flows into the cold air pipe 4 (see the white arrow in FIG. 2). That is, at the branch point P, the condensed water 7 flows downward, whereas the cold air flows upward, so that both are separated.

The cold air that has flowed into the cold air pipe 4 flows upward in the second pipe portion 32 that constitutes the cold air pipe 4, and then flows into the downstream pipe 41 that is continuous with the second pipe portion 32. When reaching the downstream end 41 b of the downstream pipe 41, the downstream pipe 41 is guided to the upstream side of the filter 53 inside the air cleaner 5 through the cold air port 54.
The cold air flowing into the air cleaner 5 passes through the filter 53 together with the intake air taken into the air cleaner 5 through the intake duct 52. At this time, dust and excessive water contained in the cold air are collected by the filter 53. The intake air includes the cold air so that the temperature is reduced, and the intake air flows down through the connection duct 51 in a high-density state and is supplied to the engine 6.

  In addition, the surface temperature of the evaporator 11 falls, so that the output of the evaporator 11 becomes large (namely, the operation rate of HVAC1 becomes high). Therefore, for example, the air in the HVAC 1 (around the evaporator 11) is cooled as the outside air temperature rises and the HVAC 1 is cooled at a higher operating rate. In this case, since the temperature of the cold air flowing into the drain pipe 2 is further lowered, the air in the drain pipe 2 is cooled to a lower temperature. That is, as the operating rate related to cooling of the HVAC 1 increases, cooler air at a lower temperature is introduced into the intake system of the engine 6 and the intake air temperature is further reduced.

[3. effect]
(1) The above-described intake air cooling structure of the engine includes the cold air pipe 4 that guides the cold air in the drain pipe 2 to the intake system of the engine 6, and thus uses the cold air in the drain pipe 2 that has been discharged conventionally. Thus, the intake air temperature of the engine 6 can be reduced. Thereby, filling efficiency and volumetric efficiency can be increased and engine output can be improved. Therefore, the power performance of the engine can be improved without deteriorating the fuel consumption. Therefore, a particularly beneficial effect can be obtained during cooling operation with a large engine load.

Further, since the intake air temperature is lowered by using the cold air that has been discharged from the drain pipe 2 in the past, energy for cooling the intake air is unnecessary, and the power performance of the engine is improved without causing an increase in the air conditioning load. Can do.
Further, since the cold air is sucked into the engine 6 by the intake negative pressure of the engine 6, it is not necessary to control the flow rate and flow direction of the cold air. That is, it is not necessary to provide an electronic control device or a control valve, and it is only necessary to connect the drain pipe 2 and the intake system with the cold air pipe 4, so that a simple configuration can be achieved and the cost can be reduced. It is easy to apply to existing engines.

  Furthermore, since the amount of reduction in the intake air temperature increases as the operating rate of the HVAC 1 increases, it is possible to supply the engine 6 with cool air corresponding to the operating state of the HVAC 1 and the engine 6. For example, if the outside air temperature is high and the intake air temperature is likely to rise, the HVAC1 will be air-cooled at a high operating rate and the engine load will increase, but it will automatically increase the intake air temperature and reduce the intake air temperature automatically. Can be obtained. Therefore, even if the operating rate related to the cooling of the HVAC 1 is high, it is possible to maintain the power performance of the engine and suppress the deterioration of fuel consumption.

(2) Further, in the above intake air cooling structure of the engine, the drain pipe 2 is extended downward from the branch point P, and the cold air pipe 4 is extended upward from the branch point P. For this reason, the condensed water 7 and the cold air in the drain pipe 2 can be reliably separated at the branch point P, and the inflow of moisture to the engine 6 side can be suppressed.
(3) Further, in the above intake air cooling structure of the engine, the cold air pipe 4 is connected to the upstream side of the filter 53 of the air cleaner 5 interposed in the intake system. For this reason, the water vapor in the cold air can be more reliably collected by the filter 53. Thereby, it can prevent that the water vapor | steam in cold air will be supplied to the engine 6. FIG.

  In the engine intake cooling structure described above, the first pipe portion 31 constituting the downstream portion of the drain pipe 2 and the second pipe portion 32 constituting the upstream portion of the cold air pipe 4 sandwich the branch point P. It is arranged in a straight line. For this reason, the moving direction of the condensed water 7 and the moving direction of cold air can be made opposite, and a water | moisture content can be efficiently removed from cold air.

[4. Modified example]
Regardless of the embodiment described above, various modifications can be made without departing from the spirit of the invention. Each structure of this embodiment can be selected as needed, or may be combined appropriately.

Although the example which adjusts the temperature (heating, cooling) and humidity of a vehicle interior as the vehicle-mounted air conditioner 1 was illustrated above, the vehicle-mounted air conditioner 1 may include at least the evaporator 11 and can cool the vehicle interior. . That is, the functions related to heating and humidity adjustment described above are not essential.
In the above, the three-way branch pipe 3 is interposed at the branch point P, but the cold air pipe 4 may be branched from the drain pipe 2 without using the three-way branch pipe 3. For example, the cold air pipe 4 may be directly connected to the drain pipe 2, or the drain pipe 2 and the cold air pipe 4 may be integrally formed.

  Further, the drain pipe 2 and the cold air pipe 4 do not have to be arranged linearly across the branch point P. For example, they may be arranged at an appropriate angle across the branch point P. Further, the drain pipe 2 is bent at a right angle with the branch point P as a base point. However, the shape of the drain pipe 2 is not limited to this, and can be changed to an appropriate shape. The drain pipe 2 may be formed in a straight line, for example, or may be bent at an angle other than a right angle with the branch point P as a base point.

Further, a separation chamber may be provided between the drain pipe 2 and the cold air pipe 4 so that the condensed water 7 and the cold air flowing from the drain pipe 2 are once retained and then separated.
Further, the shape of the cold air tube 4 is not limited to the above. For example, the cold air pipe 4 may extend linearly over the entire length, or may be formed in a meandering shape. Further, the cold air pipe 4 may be at least branched from the drain pipe 2 and connected to the intake system of the engine 6, and the connection destination of the downstream end 41 b is not limited to the air cleaner 5, for example, the intake duct 52, The connection duct 51 on the downstream side of the air cleaner 5 (filter 53) may be used. Also in this case, the intake air temperature can be reduced by guiding the cold air in the drain pipe 2 to the intake system of the engine 6 through the cold air pipe 4.

1 HVAC (on-vehicle air conditioner)
11 Evaporator
2 Drain pipe 3 Three-way branch pipe 4 Cold air pipe 5 Air cleaner 53 Filter 6 Engine 7 Condensed water P Branch location

Claims (3)

An evaporator built in an in-vehicle air conditioner for cooling the air supplied to the passenger compartment;
A drain pipe for discharging condensed water generated in the evaporator to the outside of the vehicle;
A cold air pipe branched from the drain pipe and connected to the intake system of the engine, and leading the cold air in the drain pipe to the intake system;
An intake air cooling structure for an engine characterized by comprising: The drain pipe extends downward from a branch point with the cold air pipe,
The intake air cooling structure for an engine according to claim 1, wherein the cold air pipe extends upward from a branch point with the drain pipe. The intake air cooling structure for an engine according to claim 1 or 2, wherein the cold air pipe is connected to an upstream side of a filter of an air cleaner constituting the intake system.

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