JP4609058B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device for an internal combustion engine that controls the temperature of combustion air taken into the internal combustion engine.

The lower the temperature of the combustion air drawn into the internal combustion engine, the higher the charging efficiency and the generated torque. In view of this, air that does not pass through the radiator, in other words, relatively low-temperature air that has not been heated by the radiator is known to be sucked into the internal combustion engine (see, for example, Patent Document 1).
JP 2000-257522 A

  However, even when low-temperature combustion air is inhaled, the combustion air receives a heat in the engine room while passing through the intake passage and rises in temperature near the intake port of the internal combustion engine. Specifically, even when the intake temperature at the air intake port is, for example, 30 ° C. lower than the conventional temperature, the temperature near the intake port is about 5 ° C. lower than the conventional temperature. Therefore, there is a problem that even if low-temperature combustion air is sucked, the generated torque of the internal combustion engine cannot be increased sufficiently.

  The present invention has been made in view of the above points, and an object of the present invention is to suppress an increase in the temperature of air that is passing through an intake passage and increase the torque generated by an internal combustion engine.

In order to achieve the above object, according to the first aspect of the present invention, there is provided an intake device for an internal combustion engine (20) mounted on a vehicle, wherein combustion air drawn from an air intake port (400) is taken into the internal combustion engine (20). An intake path (40, 50) leading to the internal combustion engine, a cover pipe (60) that covers the intake path (40, 50) and forms an adiabatic space (600) between the intake path (40, 50), and an internal combustion engine A radiator (300) that cools the coolant by exchanging heat between the coolant that cools (20) and the air, and a fan (302) that supplies air to the radiator (300), and has a heat insulating space (600) Ri configuration der flowing heat insulating air supplies the heat insulation air by utilizing the ram pressure, the rotational speed of the accelerator opening degree is a predetermined opening or more or an internal combustion engine (20) is higher than a predetermined rotational speed in less than the predetermined vehicle speed At the time of fan (30 ) To actuate the by characterized by supplying heat-insulating air in the heat insulation space (600).

According to this, since the space between the intake passage and the engine room is insulated by the heat insulation air flowing through the heat insulation space, the combustion air passing through the intake passage is less likely to receive heat in the engine room. Therefore, the temperature increase of the combustion air passing through the intake passage can be suppressed, and the generated torque of the internal combustion engine can be increased.
In addition, since it is not necessary to separately provide a fan for supplying the heat insulating air, it is possible to suppress a complicated configuration and an increase in mounting space.
Furthermore, in the vehicle speed range where the insulation air can be supplied by the ram pressure, it is not necessary to drive the fan for supplying the insulation air. For example, when the fan is an electric motor drive system, the power consumption is suppressed. be able to.

  In the invention according to claim 2, the intake passage (40, 50) includes an air cleaner (50) for purifying the combustion air, and the air flow upstream of the air cleaner (50) in the intake passage (40, 50) is It is covered with a covering tube (60).

  By the way, since the temperature difference between the combustion air and the air in the engine room is larger at a position closer to the air intake port in the intake path, the temperature rise width of the combustion air becomes larger. Therefore, according to the invention described in claim 2, the temperature rise of the combustion air can be efficiently suppressed.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  An embodiment of the present invention will be described. FIG. 1 is a schematic diagram of a vehicle equipped with an intake device for an internal combustion engine according to an embodiment, and FIG. 2 is a flowchart showing a control routine of a fan 302 that is executed by the electronic control unit 80 of FIG.

  As shown in FIG. 1, a bumper facer 10 having an air intake 100 is disposed at the front end of the vehicle, and the bumper facer 10 is attached to a reinforcing member 11. Above the bumper facer 10, a grill 12 having an air intake 120 is disposed. An engine room 13 is formed on the vehicle rear side of the bumper facer 10 and the grill 12, and the upper part of the engine room 13 is covered with a hood 14.

  A water-cooled internal combustion engine 20 is disposed in the engine room 13, and a heat exchange unit 30 is disposed in the engine room 13 on the vehicle rear side of the bumper fascia 10 and on the vehicle front side of the internal combustion engine 20. Has been.

  The heat exchange unit 30 is disposed on the radiator 300, the condenser 301 disposed on the upstream side of the air flow of the radiator 300, the fan 302 disposed on the downstream side of the air flow of the radiator 300, and the downstream side of the air flow of the radiator 300. A shroud 303 is provided.

  The radiator 300 cools the coolant by exchanging heat between the coolant that cools the internal combustion engine 20 and the air. The condenser 301 forms part of a vapor compression refrigeration machine in an air conditioner for performing air conditioning of the passenger compartment, and cools the refrigerant by exchanging heat between the refrigerant and air.

  The fan 302 blows cooling air to the radiator 300 and the condenser 301 and includes blades that generate an air flow and an electric motor that rotates the blades. The shroud 303 guides the air flow so that the air flow generated by the fan 302 passes through the radiator 300 and the condenser 301.

  Combustion air introduced into the internal combustion engine 20 is passed through a cylindrical intake duct 40, an air cleaner 50 that cleans the air, an intake manifold (not shown) that distributes air to each cylinder of the internal combustion engine 20, and the like. , Guided to the internal combustion engine 20. The intake duct 40, the air cleaner 50, and the intake manifold constitute the intake path of the present invention.

  The intake duct 40 has two air intake ports 400 and 401. The first air intake port 400 is located on the vehicle rear side of the grill 12 and introduces air immediately after flowing into the engine room 13, in other words, cool air that has not passed through the radiator 300 and the condenser 301. It has become. The first air inlet 400 corresponds to the air inlet of the present invention.

  The second air intake port 401 is located above the heat exchange unit 30 and introduces warm air in the engine room 13 heated by the heat of the heat exchange unit 30 or the internal combustion engine 20.

  In the intake duct 40, a known switching door 402 that adjusts the amount of cold air and the amount of warm air introduced into the internal combustion engine 20 so that the temperature of the air introduced into the internal combustion engine 20 is constant is disposed. Yes.

  The intake duct 40 is covered with a cylindrical cover tube 60. In other words, the air flow upstream side of the air cleaner 50 in the intake path is covered by the cover pipe 60. A heat insulating space 600 is formed between the intake duct 40 and the cover pipe 60.

  The air intake port 601 of the cover tube 60 is located on the vehicle rear side of the grill 12 so as to surround the first air intake port 400 of the intake duct 40. Accordingly, air is introduced into the heat insulating space 600 using the ram pressure, and air immediately after flowing into the engine room 13, in other words, cold air that has not passed through the radiator 300 and the condenser 301 is removed from the heat insulating space. 600 is introduced.

  One end of a cylindrical connection duct 70 is connected to the downstream end of the air flow in the heat insulating space 600, and the other end of the connection duct 70 is connected to the downstream side of the air flow of the radiator 300 and the upstream side of the air flow of the fan 302. Is connected.

  When the amount of air introduced into the heat insulating space 600 due to the ram pressure is small as at low vehicle speed, air is sucked through the heat insulating space 600 and the connecting duct 70 by the negative pressure generated by the fan 302. It has become.

  Incidentally, all of the intake duct 40, the cover pipe 60, and the connecting duct 70 are made of resin, and they may be individually molded, or two or all of them may be integrally molded.

  The operation of the fan 302 of the heat exchange unit 30 is controlled by the electronic control unit 80. The electronic control unit 80 includes a known microcomputer including a CPU, ROM, RAM, and the like (not shown), and performs arithmetic processing according to a program stored in the microcomputer.

  The electronic control unit 80 includes a vehicle speed sensor 81 that detects a vehicle speed and outputs a vehicle speed signal, an accelerator opening sensor 82 that detects an opening degree of a throttle valve or an accelerator pedal and outputs an accelerator opening signal, and an internal combustion engine. A rotation speed sensor 83 that detects the rotation speed of the engine 20 and outputs a rotation speed signal, a cooling liquid temperature sensor 84 that detects the temperature of the cooling liquid of the internal combustion engine 20 and outputs a cooling liquid temperature signal, and the inside of the vapor compression refrigerator A refrigerant pressure sensor 85 that detects the pressure of the refrigerant and outputs a refrigerant pressure signal is connected.

  The intake device for an internal combustion engine configured as described above supplies air to the heat insulation space 600 by the ram pressure or the negative pressure of the fan 302 and insulates the intake duct 40 and the engine room 13 by the air flowing through the heat insulation space 600. Therefore, the combustion air passing through the intake duct 40 is less likely to receive heat in the engine room 13, and the temperature rise of the combustion air passing through the intake duct 40 is suppressed, so the torque generated by the internal combustion engine 20 is reduced. Can be increased.

  Here, the electronic control unit 80 controls the operation of the fan 302 according to the control routine shown in FIG. 2, and when it is necessary to suck air into the heat insulating space 600 due to the negative pressure of the fan 302, the coolant temperature and the refrigerant pressure Regardless of the control, the fan 302 is forcibly driven.

  Hereinafter, the control of the fan 302 will be described with reference to FIG. First, a voltage Vr applied to the fan 302 (hereinafter referred to as a radiator required voltage Vr) necessary for obtaining an air volume required from the current load of the radiator 300 is calculated based on the coolant temperature (S10). Further, an applied voltage Vc to the fan 302 (hereinafter, referred to as a capacitor required voltage Vc) necessary for obtaining the air volume required from the current load of the capacitor 301 is calculated based on the refrigerant pressure (S11).

  Next, the radiator required voltage Vr and the capacitor required voltage Vc are compared (S20). If the radiator required voltage Vr is high (S20 is YES), the voltage Vf to be applied to the fan 302 (hereinafter referred to as fan applied voltage Vf). ) Is determined to be the same value as the radiator required voltage Vr. When the required capacitor voltage Vc is high (NO in S20), the fan applied voltage Vf is determined to be the same value as the required capacitor voltage Vc.

  When the vehicle is stopped, that is, when the vehicle speed is 0 km / h (YES in S25), the fan applied voltage Vf is determined as the maximum applied voltage Vmax (S70). Then, by outputting the fan applied voltage Vf determined in S70, the fan 302 is forcedly operated at the maximum capacity regardless of the coolant temperature or the refrigerant pressure.

  Further, when the vehicle is traveling (S25 is NO) and the vehicle speed is equal to or higher than the predetermined vehicle speed (20 km / h in the present embodiment) (S30 is NO), sufficient air is supplied to the heat insulating space 600 using the ram pressure. Since it can be supplied, the fan applied voltage Vf determined in S21 or S22 is output (S40).

  On the other hand, even when the vehicle is running (S25 is NO), when the vehicle speed is less than the predetermined vehicle speed (S30 is YES), the amount of air introduced into the heat insulating space 600 due to the ram pressure is small. Then, the fan 302 is forcedly operated at the maximum capacity, and air is sucked into the heat insulating space 600 by the negative pressure of the fan 302.

  That is, when the vehicle speed is less than the predetermined vehicle speed (S30 is YES), the accelerator opening is greater than or equal to the predetermined opening (S50 is YES), or the rotational speed of the internal combustion engine 20 is greater than or equal to the predetermined rotation speed (S60 is YES). In this case, the fan applied voltage Vf is determined as the maximum applied voltage Vmax (S70). Then, by outputting the fan applied voltage Vf determined in S70, the fan 302 is forcedly operated at the maximum capacity regardless of the coolant temperature or the refrigerant pressure.

  On the other hand, when the vehicle speed is less than the predetermined vehicle speed (S30 is YES), the accelerator opening is less than the predetermined opening (S50 is NO), and the rotation speed of the internal combustion engine 20 is less than the predetermined rotation speed (S60 is NO). That is, during steady running with low load and low rotation, since it is not necessary to supply air to the heat insulation space 600, the fan applied voltage Vf determined in S21 or S22 is output (S40).

  In the present embodiment, since the air flowing through the heat insulation space 600 insulates the space between the intake duct 40 and the engine room 13, the combustion air passing through the intake duct 40 is unlikely to receive heat in the engine room 13. Therefore, the temperature increase of the combustion air passing through the intake duct 40 can be suppressed, and the generated torque of the internal combustion engine 20 can be increased.

  Further, the closer to the first air intake port 400 in the intake path, the larger the temperature difference between the combustion air and the air in the engine room, so the temperature rise of the combustion air becomes larger. In the present embodiment, the upstream side of the air flow with respect to the air cleaner 50 in the intake path is covered with the cover pipe 60, so that the temperature rise of the combustion air can be efficiently suppressed.

  Further, since the heat insulating air 600 is supplied to the heat insulating space 600 using the fan 302 that supplies air to the radiator 300, it is not necessary to separately provide a fan for supplying heat insulating air, and the configuration is complicated and the mounting space is increased. Can be suppressed.

  In addition, since the heat insulation air is supplied to the heat insulation space 600 using the ram pressure, it is not necessary to drive the fan for supplying the heat insulation air in the vehicle speed range where the heat insulation air can be supplied by the ram pressure. When the fan is an electric motor drive system, power consumption can be suppressed.

  Further, in the speed range where the supply of the heat insulating air by the ram pressure is not sufficient, the fan 302 is forced to operate at the maximum capacity and the air is sucked into the heat insulating space 600 by the negative pressure of the fan 302. Insulation air can be supplied reliably and sufficiently in the region.

1 is a schematic diagram of a vehicle equipped with an intake device for an internal combustion engine according to an embodiment of the present invention. 3 is a flowchart showing a control routine of a fan 302 that is executed by the electronic control unit 80 of FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Internal combustion engine, 40 ... Intake duct (intake path), 50 ... Air cleaner (intake path), 60 ... Cover pipe, 400 ... 1st air inlet (air inlet), 600 ... Thermal insulation space.

Claims (2)

An intake device for an internal combustion engine (20) mounted on a vehicle,
An intake path (40, 50) for guiding combustion air sucked from an air inlet (400) to the internal combustion engine (20);
A cover pipe (60) that covers the intake path (40, 50) and forms a heat insulating space (600) between the intake path (40, 50) ;
A radiator (300) for cooling the coolant by exchanging heat between the coolant for cooling the internal combustion engine (20) and air;
A fan (302) for supplying air to the radiator (300),
Said heat insulation space (600) the Ri configuration der flowing heat-insulating air,
The fan (302) is supplied when the heat insulation air is supplied using ram pressure and the accelerator opening is equal to or higher than a predetermined opening or the rotational speed of the internal combustion engine (20) is equal to or higher than a predetermined speed at a speed lower than a predetermined vehicle speed. Is operated to supply the heat insulating air to the heat insulating space (600) . The intake path (40, 50) includes an air cleaner (50) for cleaning the combustion air;
2. The intake device for an internal combustion engine according to claim 1, wherein an air flow upstream side of the air cleaner (50) in the intake path (40, 50) is covered with the cover pipe (60).

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