JP2024033861A - Hybrid vehicle control device - Google Patents

Abstract

The present invention provides a control device for a hybrid vehicle that can suppress rapid temperature changes in an inverter. [Solution] A hybrid equipped with an engine and a motor, an inverter for controlling the output of the motor, and a cooling water circulation path through which cooling water flows to cool the inverter and exchanges heat with the intake pipe of the engine. A control device for a vehicle, comprising a water pump that can change the flow rate of cooling water flowing through a cooling water circulation path, and a controller that controls the water pump. a first control that controls the flow rate of cooling water by the water pump to less than a predetermined amount; and a second control that controls the flow rate of cooling water by the water pump to a predetermined amount or more when the engine is being driven. It is configured so that it can be switched. [Selection diagram] Figure 2

Description

The present invention relates to a control device for a hybrid vehicle that includes an engine and a motor as a driving force source, and an inverter for controlling the output of the motor, and particularly relates to a control device for cooling the inverter.

Patent Document 1 describes a control device for a hybrid vehicle that is configured to reduce the temperature of cooling water by dissipating heat from cooling water for cooling an inverter to intake air. This control device forcibly starts the engine when the intake air temperature, estimated based on the inverter temperature and outside air temperature, exceeds a predetermined temperature when the vehicle is running using only the power of the motor. It is configured as follows. That is, by starting the engine, intake air is made to flow, and heat is radiated from the cooling water to the intake air, thereby suppressing a rise in temperature of the inverter.

JP2013-209083A

The control device described in Patent Document 1 forcibly starts the engine when the estimated intake air temperature exceeds a predetermined temperature during EV driving using only the power of the motor. limited, and fuel efficiency may deteriorate. If the flow rate of cooling water is increased to prevent such a forced start of the engine, the driving mode in which the engine is driven switches to the EV driving mode, and the amount of heat transferred from the engine to the inverter decreases, causing the inverter temperature to decrease. Since the temperature decreases rapidly, there is a possibility that the durability of the inverter will decrease due to the load associated with the sudden temperature change.

The present invention has been made with attention to the above-mentioned technical problem, and an object of the present invention is to provide a control device for a hybrid vehicle that can suppress rapid temperature changes of an inverter.

In order to achieve the above object, the present invention includes an engine and a motor as a driving power source, an inverter for controlling the output of the motor, a cooling water for cooling the inverter, and a cooling water for cooling the inverter. A control device for a hybrid vehicle comprising a cooling water circulation path that exchanges heat with an intake pipe, the control device controlling the water pump and a water pump capable of changing the flow rate of the cooling water flowing through the cooling water circulation path. a controller for controlling the flow rate of the cooling water by the water pump to less than a predetermined amount when the engine is stopped; and a controller for driving the engine. The cooling water flow rate of the cooling water by the water pump is configured to be switchable between a second control that controls the flow rate of the cooling water to be equal to or more than the predetermined amount.

According to the present invention, when the engine is stopped, the flow rate of cooling water by the water pump is controlled to be less than a predetermined amount. Therefore, when the amount of heat received by the inverter is small due to the engine being stopped, it is possible to prevent the inverter from being rapidly cooled by the cooling water. On the other hand, when the engine is running, the flow rate of cooling water by the water pump is controlled to a predetermined amount or more. Therefore, when the amount of heat received by the inverter due to the engine being driven is large, the amount of heat radiated from the inverter by the cooling water can be increased, and it is possible to suppress the inverter from rapidly rising in temperature. That is, by controlling the flow rate of cooling water by the water pump depending on whether or not the engine is being driven, the inverter can be appropriately cooled. Therefore, when the vehicle is running using only the power of the motor, it is possible to prevent the engine from being forced to start in order to increase the amount of heat dissipated from the cooling water, and it is possible to suppress deterioration of fuel efficiency. In addition, deterioration in the durability of the inverter due to sudden changes in the temperature of the inverter can be suppressed.

1 is a diagram showing a schematic configuration of an engine intake and exhaust system applied to a hybrid vehicle according to an embodiment of the present invention. It is a figure showing temperature change of an inverter.

The present invention will be described based on embodiments shown in the drawings. Note that the embodiments described below are merely examples of embodying the present invention, and are not intended to limit the present invention.

A hybrid vehicle according to an embodiment of the present invention is a vehicle that is provided with an engine and a motor as driving power sources, and specifically, runs using only mechanical energy generated by driving the engine as an energy source, Alternatively, you can set an engine drive mode in which the vehicle uses battery power as energy in addition to the mechanical energy generated by driving the engine, or an EV drive mode in which the engine is stopped and the vehicle travels using only battery power as an energy source. This is a vehicle configured to allow That is, the hybrid vehicle in the embodiment of the present invention includes a series type hybrid vehicle, a parallel type hybrid vehicle, and a series-parallel type hybrid vehicle.

The engine can be configured similar to conventional engines. That is, it is configured to generate power by burning a mixture of air and fuel such as gasoline or diesel. FIG. 1 shows a schematic configuration of an intake and exhaust system of an engine 1. As shown in FIG. An engine 1 shown in FIG. 1 is a water-cooled engine having four cylinders 2, and each cylinder 2 is connected to an intake manifold 3. An intake pipe 4 is connected to the intake manifold 3, and the intake pipe 4 is provided with a compressor 6 of a turbocharger 5 that operates using exhaust energy as a driving force source. A water-cooled intercooler (I/C) 7 is provided downstream of the compressor 6 to cool the intake air that has been pressurized and heated by the compressor 6.

Further, in the example shown in FIG. 1, a bypass pipe 8 is provided to bypass the intercooler 7 and cause intake air to flow. That is, the upstream end of the bypass pipe 8 is connected to the upstream side of the intercooler 7 in the intake pipe 4, and the downstream end of the bypass pipe 8 is connected to the downstream side of the intercooler 7 in the intake pipe 4. It is connected. A branch ratio changing valve 9 for controlling the amount of intake air flowing through the bypass pipe 8 is provided at an upstream portion of the bypass pipe 8 . The flow division ratio changing valve 9 is configured to be able to change the ratio of the flow rate of intake air flowing through the bypass pipe 8 to the total flow rate flowing through the intake pipe 4 by controlling its opening degree.

Note that an air cleaner 10 that removes dirt and dust from the air flowing through the intake pipe 4 is disposed in the upstream side of the compressor 6 in the intake pipe 4, and an air cleaner 10 that removes dirt and dust from the air flowing through the intake pipe 4 is disposed on the downstream side of the air cleaner 10. An air flow meter 11 for measuring the flow rate of air flowing through the air flow meter 11 is provided, and a throttle valve 12 is further provided downstream of the air flow meter 11. Further, each cylinder 2 is provided with a fuel injection valve 13 that injects fuel.

An exhaust manifold 14 is further connected to each cylinder 2 described above. An exhaust pipe 15 is connected to the exhaust manifold 14, and a turbine 16 of the turbocharger 5 is disposed in the exhaust pipe 15. In addition, an exhaust purification device 17 is provided to purify unburned gas (carbon monoxide (CO) and hydrocarbons (HC)) and nitrogen oxides (NOx) contained in the exhaust gas, and to collect particulate matter. It is provided downstream of the turbine 16 in the exhaust pipe 15 . Note that the exhaust purification device 17 includes an oxidation catalyst (three-way catalyst) and a filter for collecting PM.

An EGR pipe 18 is connected to a portion of the exhaust pipe 15 on the downstream side of the exhaust purification device 17. This EGR pipe 18 is for recirculating a part of the exhaust gas to the intake pipe 4. Therefore, one end of the EGR pipe 18 is connected to the exhaust pipe 15, and the other end is connected to the intake pipe. 4 is connected to the upstream side of the compressor 6. The EGR pipe 18 is provided with an EGR cooler 19 for cooling the recirculated exhaust gas, and an EGR valve 20 for controlling the flow rate of the recirculated exhaust gas is provided on the intake pipe 4 side of the EGR cooler 19. It is provided.

The motor can be configured in the same way as a motor provided as a driving force source for a conventional hybrid vehicle or electric vehicle. In other words, in addition to functioning as a motor that outputs power by being supplied with power from a battery (not shown), it also converts mechanical energy (power) into electrical power by transmitting and entraining power from drive wheels, etc. It is configured so that it can function as a generator that converts it into energy (electricity). Specifically, it is composed of a permanent magnet type synchronous motor in which a permanent magnet is incorporated in the rotor, or an AC motor such as an induction motor.

An inverter 21 is provided to control power exchanged between the motor and the battery. This inverter 21 can be configured similarly to a conventional inverter, and converts DC power output from a battery (not shown) into desired three-phase AC power and outputs it to the motor, and also outputs AC power generated by the motor. It is configured to be able to convert the DC power into DC power and output it to the battery. The inverter 21 includes, for example, a switching circuit including switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and power MOS (Metal Oxide Semiconductor) transistors, and a switching control circuit that controls the operation of the switching elements. Note that a booster circuit such as a DC/DC converter (not shown) may be provided between the inverter 21 and the battery.

The engine 1, the motor, the inverter 21, a gear train such as a transmission (not shown), etc. are integrated into an integrated mechanical and electrical structure, and these are provided in the engine room. That is, heat generated by the engine 1 is transferred to the inverter 21 via the eAxle portion of the motor, transmission, etc. Further, the inverter 21 generates heat in response to switching operations, electrical resistance, and the like. Therefore, as shown in FIG. 1, a cooling device 22 for cooling the inverter 21 is provided.

The cooling device 22 is a water-cooled device, and includes a circulation path 23 through which cooling water for cooling the inverter 21 circulates, and a water pump (P) that can control the flow rate (flow rate) of the cooling water flowing through the circulation path 23. )24. Note that the water pump 24 is configured to be able to control the flow rate of cooling water using, for example, the power of a DC motor (not shown). The circulation path 23 corresponds to the "cooling water circulation path" in the embodiment of the present invention.

The circulation path 23 is configured to flow around the inverter 21 and to exchange heat with the bypass pipe 8 . The heat exchange area is indicated by "A", and the heat exchange part A can be constituted by, for example, a cylindrical tube made of a material with high thermal conductivity surrounding the outer periphery of the bypass pipe 8. Therefore, when the cooling water whose temperature has been increased by absorbing heat in the inverter 21 flows into the heat exchange section A, heat can be radiated from the cooling water to the intake air flowing through the bypass pipe 8, thereby cooling the cooling water. Note that the inverter 21 is provided with a temperature sensor 25 for detecting the temperature of the inverter 21.

An electronic control unit (hereinafter referred to as ECU) 26 is provided to control the water pump 24 described above. This ECU 26 corresponds to the "controller" in the embodiment of the present invention, and can be configured by a microcomputer like a conventional ECU. That is, it is configured to determine an output signal based on input data and pre-stored arithmetic expressions, maps, etc., and output the determined output signal to the water pump 24.

The data input to the ECU 26 includes, for example, whether or not the engine 1 is being driven, the opening degrees of the throttle valve 12 and the EGR valve 20, the amount of air detected by the air flow meter 11, and the temperature detected by the temperature sensor 25.

When the hybrid vehicle configured as described above is running while driving the engine 1, heat generated by the engine 1 is transmitted to the inverter 21 via the eAxle section. On the contrary, when the engine 1 is stopped, the amount of heat radiated from the engine 1 decreases, and therefore the amount of heat transferred from the engine 1 to the inverter 21 decreases. Therefore, when the engine 1 is repeatedly started and stopped, the amount of heat radiation required to control the temperature of the inverter 21 within a predetermined temperature range changes rapidly.

Therefore, the control device in the embodiment of the present invention is configured to control the flow rate (flow velocity) of the cooling water by the water pump 24 depending on whether the engine 1 is being driven. Specifically, when the engine 1 is being driven, the system is configured to control the flow rate (flow velocity) of the cooling water by the water pump 24 to a predetermined amount or more in order to increase the amount of heat dissipated by the inverter 21. There is. Similarly, when the engine 1 is stopped, the flow rate (flow rate) of the cooling water by the water pump 24 is controlled to be less than a predetermined amount in order to reduce the amount of heat released by the inverter 21. Note that the control to reduce the flow rate (flow rate) of the cooling water by the water pump 24 to less than a predetermined amount corresponds to "first control" in the embodiment of the present invention, and controls the flow rate (flow rate) of the cooling water by the water pump 24 to a predetermined amount. The control to make the amount more than a fixed amount corresponds to the "second control" in the embodiment of the present invention.

FIG. 2 shows the temperature of the inverter 21 (solid line) when the flow rate of the cooling water is controlled depending on whether or not the engine 1 is driven as described above, and the temperature of the inverter 21 when the flow rate of the cooling water is kept constant. (broken line) is shown. In the example shown in FIG. 2, the engine 1 is repeatedly started and stopped depending on the driving force and vehicle speed required for the vehicle, and the engine 1 is stopped at time t1 and time t3. Engine 1 is started at time t2 and time t4.

As shown in FIG. 2, regardless of whether or not the flow rate of cooling water is controlled, when the engine 1 is being driven, that is, before time t1, from time t2 to time t3, and after time t4, the temperature of the inverter 21 increases. However, when the engine 1 is stopped, that is, from time t1 to time t2 and from time t3 to time t4, the temperature of the inverter 21 decreases.

On the other hand, when the flow rate of the cooling water is controlled depending on whether or not the engine 1 is being driven, that is, when the engine 1 is being driven, the flow rate of the cooling water is controlled to a predetermined amount or more, and the engine 1 is stopped. In this case, when the flow rate of the cooling water is controlled to be less than a predetermined amount, the rate of temperature change of the engine 1 is small. On the other hand, when the flow rate of the cooling water is maintained constant regardless of whether or not the engine 1 is driven, the rate of temperature change of the engine 1 is large.

As described above, by controlling the flow rate of the cooling water that cools the inverter 21 depending on whether or not the engine 1 is driven, it is possible to suppress the temperature of the inverter 21 from changing rapidly. As a result, for example, when the vehicle is being driven solely by the power of the motor, the temperature of the inverter 21 can be prevented from rapidly rising and the engine 1 can be prevented from being forcedly started in order to increase the amount of heat dissipated from the cooling water. , it is possible to suppress deterioration of fuel efficiency. Furthermore, a decrease in durability of the inverter 21 due to a sudden change in the temperature of the inverter 21 can be suppressed.

1 Engine 4 Intake pipe 7 Intercooler 8 Bypass pipe 9 Diversion ratio change valve 21 Inverter 22 Cooling device 23 Circulation path 24 Water pump 25 Temperature sensor 26 Electronic control unit (ECU)
A Heat exchange section

Claims (1)

An engine and a motor as a driving power source, an inverter for controlling the output of the motor, and a cooling water circulation path through which cooling water flows to cool the inverter and exchanges heat with an intake pipe of the engine. A control device for a hybrid vehicle, comprising:
a water pump capable of changing the flow rate of the cooling water flowing through the cooling water circulation path;
and a controller that controls the water pump,
The controller includes:
a first control for controlling the flow rate of the cooling water by the water pump to less than a predetermined amount when the engine is stopped; and a first control for controlling the flow rate of the cooling water by the water pump to be less than a predetermined amount when the engine is being driven. A control device for a hybrid vehicle, characterized in that the control device for a hybrid vehicle is configured to be able to switch between a second control that controls the flow rate of the cooling water to be equal to or more than the predetermined amount.

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