JP-2026075193-A - Control method and control device for series hybrid vehicles

Abstract

[Problem] When the temperature of a battery, such as a lithium-ion battery, is low, the battery temperature is raised by discharging from the battery. [Solution] In a series hybrid vehicle, the internal combustion engine 2 that drives the power generation motor generator has an EHC 17A in the catalytic converter 17 upstream of the exhaust passage 11. When the battery temperature is lower than a predetermined battery activation temperature when the vehicle's main switch is turned on, the target temperature of the EHC 17A is set to a maximum value higher than the normal target temperature required for catalytic activation, and power is supplied to the EHC 17A to raise the battery temperature. The battery temperature can be raised without producing operating noise such as motoring. [Selection Diagram] Figure 2

Inventors

• 横山 仁
• 井上 晶
• 糸山 浩之
• 西 大紀

Assignees

• 日産自動車株式会社

Dates

Publication Date

20260508

Application Date

20241022

Claims (6)

1. A control method for a series hybrid vehicle in which a generator is driven by an internal combustion engine equipped with an electrically heated catalyst in the exhaust passage, When the vehicle's main switch is turned on and the battery temperature is lower than a predetermined battery activation temperature, the target temperature of the electric heating catalyst is set to a second target temperature higher than the normal target temperature required for catalyst activation, and power is supplied to the electric heating catalyst to raise the battery temperature. Control method for series hybrid vehicles.
2. A control method for a series hybrid vehicle according to claim 1, wherein the electric heating catalyst is energized according to the second target temperature until the battery temperature reaches the battery activation temperature, even after the electric heating catalyst temperature reaches the normal target temperature.
3. If the vehicle starts running on battery power before the battery temperature reaches the battery activation temperature, the electric heating of the catalyst is continued using the surplus battery output obtained by subtracting the required output to be supplied from the battery to the drive motor. A control method for a series hybrid vehicle according to claim 1.
4. After the vehicle starts running on battery power, if a power generation request is made due to a decrease in the battery's State of Charge (SOC), power generation by the internal combustion engine will be prohibited until the temperature of the electrically heated catalyst reaches the normal target temperature. A control method for a series hybrid vehicle according to claim 1.
5. When the battery SOC drops to a predetermined lower limit SOC, power generation by the internal combustion engine is permitted regardless of the temperature of the electrically heated catalyst. A control method for a series hybrid vehicle according to claim 4.
6. A control device for a series hybrid vehicle comprising a generator, an internal combustion engine that drives the generator, a battery that stores the generated electricity, a drive motor, and an electrically heated catalyst provided in the exhaust passage of the internal combustion engine, When the vehicle's main switch is turned on and the battery temperature is lower than a predetermined battery activation temperature, the target temperature of the electrically heated catalyst is set to a second target temperature higher than the normal target temperature required for catalyst activation, and power is supplied to the electrically heated catalyst to raise the battery temperature. Control system for series hybrid vehicles.

Description

This invention relates to the control of a series hybrid vehicle that operates by supplying power from a battery that temporarily stores electricity to a drive motor. In many vehicle drive batteries, such as lithium-ion batteries, low battery temperatures in cold climates increase internal resistance, leading to a decrease in discharge voltage and capacity (SOC). Consequently, this results in a reduction in the vehicle's acceleration performance. Patent Document 1 discloses a technology for an electric vehicle equipped with motor generators on both the front and rear wheels. In this system, the vehicle is driven by the motor generator on the front wheels while generating electricity through regeneration by the motor generator on the rear wheels. The power is circulated back to the battery through this discharge and charging cycle. In this system, the active discharge and charging of the battery generates heat due to internal resistance, causing the battery temperature to rise. Japanese Patent Publication No. 2004-320882 A diagram illustrating the configuration of a series hybrid vehicle according to one embodiment.Diagram illustrating the configuration of the intake and exhaust systems of an internal combustion engine.A flowchart showing the processing flow of battery temperature rise control in one embodiment.A time chart showing the operation of battery temperature rise control in one embodiment. The following describes in detail an embodiment of this invention based on the drawings. Figure 1 schematically shows the configuration of a series hybrid vehicle in one embodiment to which this invention is applied. The series hybrid vehicle comprises a power generation motor generator 1 that mainly operates as a generator, an internal combustion engine 2 used as a power generation internal combustion engine that drives the power generation motor generator 1 according to power demands, a drive motor generator 4 that mainly operates as a motor to drive the drive wheels 3, and a battery 5 that stores the generated electricity. The electricity obtained by the internal combustion engine 2 driving the power generation motor generator 1 is stored in the battery 5 via an inverter device (not shown). The drive motor generator 4 is driven and controlled using the power from the battery 5. The electricity generated during regeneration by the drive motor generator 4 is also stored in the battery 5 via an inverter device (not shown). The battery 5 is a secondary battery such as a lithium-ion battery. The operation of the motor generators 1 and 4, the charging and discharging of the battery 5, and the operation of the internal combustion engine 2 are controlled by the controller 6. The controller 6 is composed of multiple controllers connected to each other so as to be able to communicate with one another, including a motor controller 7 that controls the motor generators 1 and 4, an engine controller 8 that controls the internal combustion engine 2, and a battery controller 9 that manages the battery 5. Information such as the opening of the accelerator pedal (not shown) and vehicle speed is input to the controller 6. The battery controller 9 also monitors the temperature and voltage of the battery 5 and determines the State of Charge (SOC) of the battery 5 based on the voltage and current of the battery 5. When the SOC falls to a predetermined lower limit level, the internal combustion engine 2 is started via the engine controller 8 and power generation is performed. The driving modes of such a series hybrid vehicle include an EV mode in which the vehicle runs on the power of the battery 5 without combustion operation of the internal combustion engine 2, and a HEV mode in which the vehicle runs while generating power through combustion operation of the internal combustion engine 2. Furthermore, even if the SOC is above the lower limit level, if the required driving force of the vehicle is relatively large, the internal combustion engine 2 is driven and the vehicle runs in HEV mode. Therefore, while the vehicle's main switch is on, the internal combustion engine 2 will repeatedly cycle between combustion operation and combustion shutdown. Figure 2 shows the configuration of the intake and exhaust systems of the internal combustion engine 2. The internal combustion engine 2 in one embodiment is a four-stroke cycle spark-ignition internal combustion engine (a so-called gasoline engine) equipped with a turbocharger 13 as a supercharger. For example, it is a so-called direct-injection type internal combustion engine where fuel is injected directly into the cylinder by a fuel injector. A port injection type configuration is also possible. The intake passage 12 of the internal combustion engine 2 contains a compressor 15 of a turbocharger 13. Downstream of the compressor 15 is an electronically controlled throttle valve 21 that controls the intake air volume. Between the compressor 15 and the throttle valve 21 is a water-cooled in