Vehicle control system

Abstract

To provide a vehicle control device that can suppress the deterioration of fuel efficiency. [Solution] The HCU10 refers to a threshold map and determines an EV prohibition temperature threshold from the vehicle's latitude and longitude (S2). If the battery temperature is below the EV prohibition temperature threshold (S4), the HCU10 prohibits the vehicle 1 from running in EV mode (S5), and if the battery temperature is not below the EV prohibition temperature threshold (S4), it allows the vehicle 1 to run in EV mode (S6).

Description

[[Technical Field]]

[0001] The present invention relates to a vehicle control device. [[Background Art]]

[0002] Conventionally, Patent Document 1 proposes a technology relating to a vehicle control system that acquires map information and area information including an EV mode travel area and a charge mode travel area specified by a user on a map in the map information, and the vehicle travels in EV mode when in the EV mode travel area and travels in charge mode when in the charge mode travel area. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2024-083995 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] However, the conventional technology described above has a problem in that fuel efficiency is deteriorated because the vehicle cannot be driven in EV mode within the charge mode travel area even when the vehicle is in a state where it can be driven in EV mode.

[0005] The present invention has been made to solve the above-described problems, and an object thereof is to provide a vehicle control device capable of suppressing deterioration of fuel efficiency. [[Means for Solving the Problem]]

[0006] The vehicle control device according to the present invention comprises an engine, a generator that generates electricity using the driving force of the engine, a battery on which the electricity generated by the generator is charged, and an electric motor that is driven by the electricity charged in the battery, and is a vehicle control device that operates in either an EV mode, which operates by driving the electric motor, or an HEV mode, which operates by driving the engine and the electric motor, and includes a control unit that prohibits the vehicle from operating in the EV mode when the battery temperature is below an EV prohibition temperature threshold, and the control unit is configured to determine the EV prohibition temperature threshold according to the vehicle's operating environment. [Effects of the Invention]

[0007] The present invention can provide a vehicle control device that can suppress the deterioration of fuel efficiency. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram of a vehicle equipped with a vehicle control device according to one embodiment of the present invention. [Figure 2] Figure 2 is a conceptual diagram illustrating a threshold map referenced by a vehicle control device according to one embodiment of the present invention. [Figure 3] Figure 3 is a flowchart showing the driving mode control operation of a vehicle control device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] A vehicle control device according to one embodiment of the present invention comprises an engine, a generator that generates electricity using the driving force of the engine, a battery that is charged with the electricity generated by the generator, and an electric motor that is driven by the electricity charged in the battery. The vehicle operates in either an EV mode, where the vehicle is driven by the electric motor, or an HEV mode, where the vehicle is driven by both the engine and the electric motor. The control device includes a control unit that prohibits the vehicle from operating in EV mode when the battery temperature is below an EV prohibition temperature threshold, and the control unit determines the EV prohibition temperature threshold according to the vehicle's operating environment. As a result, the vehicle control device according to one embodiment of the present invention can suppress deterioration of fuel efficiency. [Examples]

[0010] Hereinafter, a vehicle equipped with a vehicle control device according to one embodiment of the present invention will be described with reference to the drawings.

[0011] As shown in Figure 1, the vehicle 1 is composed of an engine 2, a battery 3, a first motor 4 (hereinafter also referred to as "MG1"), a first inverter 5, a second motor 6 (hereinafter also referred to as "MG2"), a second inverter 7, a boost converter 8, drive wheels 9, and a hybrid controller (hereinafter simply referred to as "HCU") 10.

[0012] Engine 2 has multiple cylinders. In this embodiment, engine 2 generates power by performing a series of four strokes for each cylinder, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0013] Battery 3 is composed of a rechargeable secondary battery, such as a lithium-ion battery. Battery 3 stores the power generated by MG1 and MG2 and supplies power to drive MG1 and MG2.

[0014] The MG1 is positioned to operate in conjunction with the crankshaft of the engine 2. The MG1 is connected to the battery 3 via the first inverter 5 and the boost converter 8. The MG1 has the function of an electric motor that rotates the crankshaft of the engine 2 by rotating when power is supplied from the battery 3, and the function of a generator that converts the power generated by the engine 2 into electricity. The MG1 constitutes the generator in this invention.

[0015] The MG2 is configured to be linked with the drive wheels 9 via power transmission components such as a gear mechanism. The MG2 is connected to the battery 3 via a second inverter 7 and a boost converter 8.

[0016] MG2 has the function of an electric motor that rotates the drive wheel 9 by rotating when power is supplied from battery 3 and MG1, and the function of a generator that converts the rotational force of the drive wheel 9 into electricity. MG2 constitutes the electric motor in this invention.

[0017] The boost converter 8 is installed between the battery 3 and the first inverter 5 and the second inverter 7. It boosts the voltage of the power supplied from the battery 3 to the first inverter 5 and the second inverter 7, and lowers the voltage of the power supplied from the first inverter 5 and the second inverter 7 to the battery 3.

[0018] The HCU10 consists of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, input ports, and output ports.

[0019] A ROM of this computer unit stores various constants, various maps, and other data together with a program for causing the computer unit to function as HCU10. That is, when the CPU executes the program stored in the ROM using the RAM as a work area, this computer unit functions as HCU10 in the present embodiment.

[0020] Various sensors including a temperature sensor 21 that detects the temperature of the battery 3 and a GPS (Global Positioning System) receiver 22 are connected to an input port of the HCU 10. The GPS receiver 22 receives radio waves transmitted from a plurality of artificial satellites.

[0021] The HCU 10 detects the latitude and longitude of the vehicle 1 (hereinafter also simply referred to as "own vehicle position") based on data represented by the radio waves received by the GPS receiver 22. As described above, the HCU 10 has a function as a position detection unit 30 that detects the own vehicle position.

[0022] Various controlled objects including a first inverter 5, a second inverter 7, and a boost converter 8 are connected to an output port of the HCU 10. The HCU 10 controls the various controlled objects connected to the output port based on information obtained from the various sensors connected to the input port.

[0023] In the present embodiment, the HCU 10 selects one of two travel modes: an EV mode in which MG2 is driven to cause the vehicle 1 to travel, and an HEV mode in which the engine 2 and MG2 are driven to cause the vehicle 1 to travel.

[0024] In the EV mode, the vehicle 1 is driven by driving MG2 with electric power supplied from the battery 3. In the HEV mode, the vehicle 1 is driven by driving MG2 with electric power generated by MG1 driven by the engine 2 and electric power supplied from the battery 3.

[0025] The HCU10 selects HEV mode if the charge level of battery 3 is below a lower limit or if the requested output from vehicle 1 is above a predetermined value, and selects EV mode if the charge level of battery 3 is not below a predetermined lower limit and the requested output from vehicle 1 is above a predetermined value.

[0026] The HCU10 functions as a control unit 31 that prohibits the vehicle from running in EV mode if the temperature of the battery 3 is below the EV prohibition temperature threshold. The HCU10 determines the EV prohibition temperature threshold according to the vehicle's driving environment.

[0027] In this embodiment, the vehicle's driving environment is defined as the vehicle's own position. As shown in Figure 2, the ROM of the HCU10 stores a threshold map in which EV prohibition temperature thresholds are associated with the vehicle's own position. The HCU10 refers to the threshold map and determines the EV prohibition temperature threshold from the vehicle's own position.

[0028] The threshold map associates the EV no-go temperature thresholds so that they decrease as the latitude of vehicle 1 increases. Therefore, HCU10 determines the EV no-go temperature thresholds so that they decrease as the latitude of vehicle 1 increases.

[0029] The threshold map shown in Figure 2 is based on the assumption that Vehicle 1 will be used in Japan. Therefore, in regions where Vehicle 1 is at a low latitude, the EV prohibition temperature threshold is associated with increasing longitude of Vehicle 1.

[0030] The driving mode control operation of the HCU10 configured as described above will be explained with reference to Figure 3. Note that the driving mode control operation described below will be repeatedly executed throughout the period in which the HCU10 is operating.

[0031] First, in S1, the HCU10 determines whether or not the GPS receiver 22 is receiving a normal signal. If the HCU10 determines in S1 that the GPS receiver 22 is receiving a normal signal, it executes the process in S2. If the HCU10 determines in S1 that the GPS receiver 22 is not receiving a normal signal, it executes the process in S3.

[0032] In S2, the HCU10 refers to the threshold map and determines the EV prohibited temperature threshold based on the latitude and longitude received by the GPS receiver 22. After executing the process in S2, the HCU10 executes the process in S4.

[0033] In S3, HCU10 sets the EV prohibited temperature threshold to a default value. After executing the process in S3, HCU10 executes the process in S4. In S4, HCU10 determines whether the temperature of the battery 3 detected by the temperature sensor 21 (hereinafter also simply referred to as "battery temperature") is below the EV prohibited temperature threshold.

[0034] In S4, if it is determined that the battery temperature is below the EV prohibition temperature threshold, the HCU10 executes the process in S5. In S4, if it is determined that the battery temperature is not below the EV prohibition temperature threshold, the HCU10 executes the process in S6.

[0035] In S5, if the HCU10 has not prohibited vehicle 1 from running in EV mode, it prohibits vehicle 1 from running in EV mode. After executing the process in S5, the HCU10 terminates the driving mode control operation.

[0036] In S6, if HCU10 has not permitted vehicle 1 to run in EV mode, it permits vehicle 1 to run in EV mode. After executing the process in S6, HCU10 terminates the driving mode control operation.

[0037] As described above, the vehicle control device according to this embodiment can increase the period during which the vehicle 1 is driven in EV mode by setting an EV prohibition temperature threshold according to the driving environment of the vehicle 1, thereby suppressing deterioration of fuel efficiency.

[0038] Furthermore, in the vehicle control device according to this embodiment, the driving environment of vehicle 1 includes the latitude of vehicle 1, so the period during which vehicle 1 is driven in EV mode can be increased according to the latitude of vehicle 1.

[0039] Furthermore, the vehicle control device according to this embodiment sets an EV prohibition temperature threshold that decreases as the latitude of the vehicle 1 increases, thereby increasing the period during which the vehicle 1 is driven in EV mode in cold regions.

[0040] On the other hand, the vehicle control device according to this embodiment sets an EV prohibition temperature threshold that increases as the latitude of the vehicle 1 decreases, thus suppressing the operation of the vehicle 1 in EV mode in non-cold regions.

[0041] When the battery temperature is low, the output of battery 3 decreases, making it easier for the driving mode to switch from EV mode to HEV mode. When the driving mode switches from EV mode to HEV mode, the engine 2 is started before the MG1 starts generating electricity. This causes a delay between the time an increase in vehicle 1's output is requested and the actual increase in vehicle 1's output, which may worsen drivability.

[0042] The vehicle control device according to this embodiment suppresses the operation of vehicle 1 in EV mode in non-cold regions, thereby reducing the frequency of the driving mode switching from EV mode to HEV mode, and thus suppressing deterioration of drivability.

[0043] In this embodiment, an example of applying the vehicle control device according to the present invention to a series hybrid vehicle has been described. However, the vehicle control device according to the present invention can be applied to other hybrid vehicles, such as parallel hybrid vehicles.

[0044] Furthermore, in this embodiment, an example was described in which the driving environment of vehicle 1 was defined as the latitude and longitude of vehicle 1. In contrast, the driving environment of vehicle 1 does not necessarily have to include the longitude of vehicle 1.

[0045] Furthermore, the driving environment of vehicle 1 may further include at least one of the vehicle's altitude, time of day, and season. The HCU 10 can detect the vehicle's altitude, time of day, and season based on the data represented by the radio waves received by the GPS receiver 22.

[0046] Furthermore, in this embodiment, a threshold map was described assuming that vehicle 1 is used in Japan. In contrast, the ROM of the HCU 10 may store multiple threshold maps corresponding to multiple countries, and the HCU 10 may select the threshold map to reference based on the vehicle's position.

[0047] Furthermore, threshold maps may be defined not only for each country, but also for the regions that make up each country, or for blocks numerically divided by latitude and longitude.

[0048] Furthermore, although this embodiment describes an example in which the EV prohibition temperature threshold is set to a value of 1, the EV prohibition temperature threshold may also be set with hysteresis. For example, the HCU 10 may set an EV prohibition temperature threshold for determining whether to allow vehicle 1 to run in EV mode with a predetermined margin over the EV prohibition temperature threshold for determining whether to prohibit vehicle 1 from running in EV mode.

[0049] Furthermore, as explained with reference to Figure 3, in S3 of the driving mode control operation, the HCU10 sets the EV prohibition temperature threshold to a default value. However, if the HCU10 has already performed the process in S2, it may maintain the EV prohibition temperature threshold set in the completed S2 in S3.

[0050] Furthermore, in this embodiment, in cold regions, the EV prohibition temperature threshold is lower, which reduces the period during which vehicle 1 runs in HEV mode. As a result, the warm-up of engine 2 is delayed, and heating performance deteriorates. Therefore, a PTC (Positive Temperature Coefficient) heater or the like may be used to compensate for the deteriorated heating performance.

[0051] Although embodiments of the present invention have been disclosed above, it is clear that modifications can be made to these embodiments without departing from the scope of the present invention. The embodiments of the present invention are disclosed on the premise that equivalents with such modifications are included in the invention described in the claims. [Explanation of Symbols]

[0052] 1 vehicle 2 engines 3 Batteries 4. First motor (generator) 6. Second motor (electric motor) 31 Control Unit

Claims

1. The engine and A generator that generates electricity using the driving force of the aforementioned engine, A battery that is charged with electricity generated by the aforementioned generator, The system comprises an electric motor powered by electricity stored in the aforementioned battery, The EV mode is used to drive the vehicle by using the aforementioned electric motor, A control device for a vehicle that travels in either the engine and the electric motor driving the vehicle, or in an HEV mode, The system includes a control unit that prohibits the vehicle from running in EV mode when the battery temperature is below an EV prohibition temperature threshold. The control unit is a vehicle control device that determines the EV prohibition temperature threshold according to the driving environment of the vehicle.

2. The vehicle control device according to claim 1, wherein the driving environment of the vehicle includes the latitude of the vehicle.

3. The vehicle control device according to claim 2, wherein the control unit determines the EV prohibition temperature threshold to decrease as the latitude of the vehicle increases.

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