JP2020056377A - Internal combustion engine control device - Google Patents

Abstract

To suppress a reduction in intake volumetric efficiency while cooling a heat generation section in an internal combustion engine where the heat generation section is cooled with intake air taken into the internal combustion engine.SOLUTION: An internal combustion engine comprises: an intake air passage where a first branch passage and a second branch passage converge into a flow passage communicating with a cylinder; an air-cooling section which is installed on the first branch passage and cools intake air flowing therein; a heat generation section which is installed at a downstream side of the air-cooling section on the first branch passage so as to be able to exchange heat with the intake air flowing therein; and an intake air adjustment section which adjusts a flow rate ratio of first intake air flowing from the first branch passage to the cylinder to second intake air flowing from the second branch passage to the cylinder. When a first temperature which is a temperature of the intake air passing through the heat generation section is higher than a second temperature which is a temperature of the intake air flowing in the second branch passage, a control device controls the intake air adjustment section in a manner that makes the flow rate ratio of the second intake air to the first intake air higher than the flow rate ratio when the first temperature is equal to or lower than the second temperature.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a control device for an internal combustion engine.

  Patent Literature 1 discloses a technique for cooling a battery without complicating the structure. In this technique, a cooling chamber is arranged in the middle of an intake pipe connected to an engine. The battery is accommodated in the cooling chamber. This makes it possible to cool the battery without complicating the structure.

JP-A-2006-052836

  In the above technique, the air after cooling the battery is always drawn into the engine. For this reason, when the amount of heat radiation from the battery is large, the temperature of the intake air taken into the engine becomes high, and there is a problem that the output is reduced due to the decrease in intake volume efficiency.

  The present invention has been made in view of the above-described problems, and in an internal combustion engine that cools a heat generating portion using intake air drawn into the internal combustion engine, suppresses a decrease in intake volume efficiency while cooling the heat generating portion. It is an object of the present invention to provide a control device for an internal combustion engine that can perform the control.

  The present invention is applied to a control device for an internal combustion engine in order to solve the above problems. The internal combustion engine includes an intake passage configured to communicate with the cylinder after the first branch and the second branch merge, and an intake that is disposed in the first branch and cools intake air flowing through the first branch. A cooling unit, a heating unit disposed downstream of the intake cooling unit in the first branch, and arranged so as to be able to exchange heat with intake air flowing through the first branch, and a second heat flowing from the first branch to the cylinder. An intake adjustment unit is provided for adjusting a flow rate ratio between one intake air and a second intake air flowing from the second branch passage to the cylinder. When the first temperature that is the temperature of the intake air that has passed through the heat generating unit is higher than the second temperature that is the temperature of the intake air flowing through the second branch passage, the first intake air temperature is lower than when the first temperature is equal to or lower than the second temperature. Is controlled so as to increase the flow ratio of the second intake air to the intake air.

  According to the present invention, when the first temperature of the intake air that has passed through the heat generating unit is higher than the second temperature of the intake air flowing through the second branch, the intake air flowing to the cylinder is less than when the first temperature is equal to or lower than the second temperature. The amount of intake air that has passed through the heat generating portion is relatively reduced. Thereby, it is possible to suppress a decrease in the intake volume efficiency of the internal combustion engine while cooling the heat generating portion.

FIG. 1 is a diagram for explaining a configuration of a control system for an internal combustion engine according to a first embodiment. It is a figure showing an example of a control pattern of an intake adjustment part. It is a figure showing other examples of a control pattern of an intake adjustment part. 5 is a flowchart of a routine executed by the system according to the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in the embodiments described below, when referring to the number of each element, such as the number, quantity, amount, range, etc., unless otherwise specified or in principle clearly specified by the number, the reference The present invention is not limited to the numbers set forth above. In addition, structures, steps, and the like described in the embodiments described below are not necessarily essential to the present invention, unless otherwise specified or clearly specified in principle.

1. Embodiment 1 FIG.
Embodiment 1 will be described with reference to the drawings.

1-1. 1. Configuration of First Embodiment FIG. 1 is a diagram for explaining a configuration of a control system for an internal combustion engine according to a first embodiment. The control system 100 for an internal combustion engine of the present embodiment is mounted on an EV vehicle equipped with a generator called a range extender EV powered by an engine. As shown in FIG. 1, a control system 100 for an internal combustion engine according to the present embodiment includes an internal combustion engine (engine) 10. The engine 10 is used as a generator for charging an EV battery 16 described later. The engine 10 is provided with three cylinders 101 in series. An intake manifold 102 is attached to the engine 10 so as to communicate with the intake side of each cylinder 101. The intake manifold 102 is connected to an intake passage 12 through which intake air flows.

  The intake passage 12 includes a first branch passage 121, a second branch passage 122, an intake introduction passage 123, and an intake discharge passage 124. One end of each of the first branch passage 121 and the second branch passage 122 is open to the atmosphere, and the other end thereof is connected to one end of the intake introduction passage 123 after being joined. The other end of the intake passage 123 communicates with the intake manifold 102. One end of the intake discharge passage 124 is open to the atmosphere, and the other end communicates with the middle of the first branch passage 121.

  In the first branch 121, the battery cooling device 14 and the EV battery 16 are arranged in this order from the upstream side on the intake upstream side of the communication portion of the intake discharge passage 124. The battery cooling device 14 functions as an intake cooling unit that cools intake air flowing through the first branch passage 121 on the upstream side of the EV battery 16. The EV battery 16 is housed inside the first branch passage 121, and is configured to be able to exchange heat with air flowing through the first branch passage 121.

  An intake adjusting section 18 is provided in the intake passage 12. Specifically, the intake adjusting section 18 includes a first control valve 181 disposed at a communication section of the intake discharge path 124 and a second control valve 181 disposed at a junction of the first branch path 121 and the second branch path 122. It is constituted by a control valve 182. The first control valve 181 is configured to include a flap that is driven to rotate. By adjusting the rotation angle of the flap, the first control valve 181 opens a flow path that flows from the first branch path 121 to the intake introduction path 123 and performs an intake discharge path. A first flow path configuration in which the flow path flowing to the side of the intake passage 124 is blocked, and a flow path in which the flow path flowing from the first branch path 121 to the side of the intake introduction path 123 is closed and the flow path that flows to the side of the intake discharge path 124 is opened. It is configured to be able to switch between a two-channel form. The second control valve 182 is configured to include a flap that is driven to rotate. By adjusting the rotation angle of the flap, the flow path that flows from the first branch passage 121 to the intake introduction passage 123 is opened and the second control valve 182 is opened. A third flow path configuration that shuts off a flow path that flows from the path 122 to the intake introduction path 123, and a flow path that cuts off the flow path that flows from the first branch path 121 to the intake introduction path 123 and intake air that flows from the second branch path 122. It is configured to be able to switch between a fourth flow path configuration that opens a flow path that flows to the introduction path 123 side. The air filter 20 is disposed in the intake passage 123.

  In the following description, the intake air flowing from the first branch passage 121 to the cylinder 101 through the intake introduction passage 123 is referred to as “first intake air”. The intake air flowing from the second branch passage 122 to the cylinder 101 through the intake passage 123 is referred to as “second intake air”.

  The control system 100 for an internal combustion engine according to the present embodiment includes an ECU (Electronic Control Unit) 30. The ECU 30 is a control device that comprehensively controls the entire control system, and the control device according to the present invention is embodied as one function of the ECU 30.

  The ECU 30 has at least an input / output interface, a ROM, a RAM, and a CPU. The input / output interface captures a signal of a sensor included in the control system 100 and outputs an operation signal to an actuator included in the engine 10. Sensors are attached to various parts of the control system 100. A temperature sensor 22 is provided downstream of the EV battery 16 in the first branch 121. Temperature sensor 22 detects first intake air temperature Tb after heat exchange with EV battery 16. The second branch 122 is provided with a temperature sensor 24. The temperature sensor 24 detects the temperature T of the second intake air flowing through the second branch 122. The ECU 30 processes the received signal of each sensor and operates each actuator according to a predetermined control program. Actuators operated by the ECU 30 include a first control valve 181 and a second control valve 182 that constitute the intake adjustment unit 18. The ROM stores various control programs for controlling the engine 10 and various control data including maps. The CPU reads the control program from the ROM, executes the control program, and generates an operation signal based on the received sensor signal. It should be noted that there are many actuators and sensors connected to the ECU 30 other than those shown in the figure, but description thereof will be omitted in this specification.

1-2. Intake Air Temperature Control of First Embodiment Combustion control of engine 10 performed by ECU 30 includes intake air temperature control. In the intake air temperature control of the present embodiment, the first control valve 181 and the second control valve constituting the intake air adjusting unit 18 are used by using the temperature Tb detected by the temperature sensor 22 and the temperature T detected by the temperature sensor 24. Control valve 182.

  FIG. 2 is a diagram illustrating an example of a control pattern of the intake adjustment unit. In the control pattern A shown in this figure, the ECU 30 controls the first control valve 181 to the first flow path form and controls the second control valve 182 to the third flow path form. According to such a control pattern A, the first intake air introduced into the first branch passage 121 is cooled by the battery cooling device 14. The cooled first intake air exchanges heat with the EV battery 16 in the process of passing around the EV battery 16. The first intake air after the heat exchange is sucked into each cylinder 101 of the engine 10 from the first branch passage 121 through the intake passage 123 and the intake manifold 102 in order.

  FIG. 3 is a diagram illustrating another example of the control pattern of the intake adjustment unit. In the control pattern B shown in this figure, the ECU 30 controls the first control valve 181 to the second flow path form and controls the second control valve 182 to the fourth flow path form. According to such a control pattern B, the air introduced into the first branch 121 is cooled by the battery cooling device 14. The cooled atmosphere exchanges heat with the EV battery 16 in the process of passing around the EV battery 16. The air after the heat exchange is discharged from the first branch passage 121 to the intake discharge passage 124. Further, the second intake air introduced from the second branch passage 122 is sucked into each cylinder 101 of the engine 10 through the intake passage 123 and the intake manifold 102 in order.

Here, the air density ρ [kg / m ³ ] at t [° C.] is represented by the following equation, where P [atm] is the atmospheric pressure, and e [atm] is the water vapor pressure.

  As shown in Expression (1), the air density ρ of the air increases as the temperature t decreases. For this reason, if the first intake air cooled by the battery cooling device 14 is used as the intake air to be taken into the cylinder 101 of the engine 10 as in the above-described control pattern A, the volumetric efficiency of the intake air is increased and the engine 10 can be improved. Further, when the first intake air is sucked into the cylinder 101, the flow rate of the first intake air passing around the EV battery 16 increases, so that the cooling of the EV battery 16 can be promoted.

  However, when the amount of heat radiation from the EV battery 16 is large, the temperature of the first intake air after heat exchange with the EV battery 16 may excessively increase. When such high-temperature first intake air is sucked into the cylinder 101, the volumetric efficiency of the intake air decreases, and the output of the engine 10 decreases. In such a case, as in the case of the control pattern B, the volumetric efficiency of the intake air may be increased by using the second intake air sucked from the second branch passage 122 as the intake air sucked into the cylinder 101.

  Therefore, in the intake air temperature control of the first embodiment, the control pattern of the intake air adjustment unit 18 is changed according to the temperature Tb of the first intake air after heat exchange with the EV battery 16. Specifically, when the temperature Tb of the first intake air after the heat exchange with the EV battery 16 is equal to or lower than the temperature T of the second intake air flowing through the second branch passage 122, the control pattern A is realized by the ECU 30. The intake adjusting unit 18 is controlled in such a manner as to be described. On the other hand, when the temperature Tb is higher than the temperature T, the ECU 30 controls the intake adjustment unit 18 so that the control pattern B is realized. According to such control, low-temperature intake air can be sequentially selected and sucked into the cylinder 101, so that the output of the engine 10 can be kept high sequentially.

1-3. Specific Processing of Control Executed in System of First Embodiment Next, specific processing of a routine executed by ECU 30 will be described with reference to a flowchart.

  FIG. 4 is a flowchart of a routine executed by the system according to the first embodiment. The routine shown in FIG. 4 is repeatedly executed at a predetermined control cycle. In the routine shown in FIG. 4, first, the ECU 30 determines whether or not the engine 10 is ON (step S100). Here, the ECU 30 determines whether or not the engine 10 is running. As a result, when the engine 10 is ON, the process proceeds to the next step, and when the engine 10 is OFF, this routine is ended.

  In the next step, the ECU 30 determines whether the temperature Tb detected by the temperature sensor 22 is equal to or lower than the temperature T detected by the temperature sensor 24 (Step S102). As a result, when it is recognized that Tb ≦ T is satisfied, it can be determined that the output of the engine 10 is improved when the first intake air is sucked into the cylinder 101. In this case, the process proceeds to the next step S104. In step S104, the ECU 30 controls the intake adjustment section 18 so that the flow path configuration of the control pattern A is formed.

  On the other hand, as a result of the processing in step S102, when the establishment of Tb ≦ T is not recognized, it can be determined that the output of the engine 10 is improved by inhaling the second intake air into the cylinder 101. In this case, the process proceeds to the next step S106. In step S106, the ECU 30 controls the intake adjustment section 18 so that the flow path configuration of the control pattern B is formed.

  As described above, according to the control system 100 of the present embodiment, it is possible to increase the output of the engine 10 while suppressing the decrease in the intake volume efficiency while cooling the EV battery 16.

  In the control system 100 according to the first embodiment, the temperature Tb corresponds to the “first temperature” of the present invention, the temperature T corresponds to the “second temperature” of the present invention, and the battery cooling device 14 The EV battery 16 corresponds to the “heat generating unit” of the present invention, and the ECU 30 corresponds to the “control device” of the present invention.

1-3. Modification of System of First Embodiment The control system 100 of the first embodiment may adopt a modified form as described below.

  In the control system 100 of the first embodiment described above, the system that cools the EV battery 16 as the heat generating unit has been described. However, the heat generating portion applicable to the present invention is not limited to this. That is, any heat-generating component that requires cooling, such as a PCU, various control devices, engine components, and actuators, can be applied as the heat-generating portion of the present invention.

  The first control valve 181 adjusts the rotation angle of the flap in a stepwise manner, so that the air flows from the first branch passage 121 toward the intake passage 123 and flows from the first branch passage 121 to the intake discharge passage 124. The air flow ratio may be configured to be adjustable.

  The second control valve 182 adjusts the rotation angle of the flap in a stepwise manner, so that the air flows from the first branch passage 121 to the intake passage 123 and the second branch passage 122 flows to the intake passage 123 side. The air flow ratio may be configured to be adjustable. In this case, the ECU 30 increases the flow ratio of the air flowing from the second branch passage 122 to the intake introduction passage 123 when Tb ≦ T is not established, compared to when the establishment is satisfied. The control may be performed as follows.

  The temperature Tb is not limited to the value detected by the temperature sensor 22, and a value estimated by a known method may be used. Also, the temperature T is not limited to the value detected by the temperature sensor 24, and a value estimated by a known method may be used.

Reference Signs List 10 engine 12 intake passage 121 first branch passage 122 second branch passage 123 intake introduction passage 124 intake discharge passage 14 battery cooling device 16 EV battery 18 intake control unit 181 first control valve 182 second control valve 20 air filter 22 temperature sensor 24 Temperature sensor 30 ECU (Electronic Control Unit)
100 Control system 101 Cylinder 102 Intake manifold

Claims (1)

A control device for an internal combustion engine,
The internal combustion engine,
An intake passage configured to communicate with the cylinder after the first branch and the second branch merge,
An intake cooling unit that is arranged in the first branch and cools intake air flowing through the first branch.
A heat-generating unit arranged on the downstream side of the intake cooling unit in the first branch, and arranged so as to be able to exchange heat with intake air flowing through the first branch;
A first intake that flows from the first branch to the cylinder, and an intake adjusting unit that adjusts a flow ratio of a second intake that flows from the second branch to the cylinder,
The control device includes:
When the first temperature that is the temperature of the intake air that has passed through the heat generating unit is higher than the second temperature that is the temperature of the intake air flowing through the second branch, the temperature of the first intake air is lower than when the temperature is equal to or lower than the second temperature. A control device for an internal combustion engine, wherein the control device is configured to control the intake adjustment section so as to increase a flow rate ratio of the second intake air.

Images