Search

JP-2026075848-A - Control device for hybrid vehicles, and control method for hybrid vehicles

JP2026075848AJP 2026075848 AJP2026075848 AJP 2026075848AJP-2026075848-A

Abstract

[Problem] To provide a control device for a hybrid vehicle that can ensure good drivability while suppressing NOx emissions to the outside of the vehicle, even when an abnormality occurs in the SCR system. [Solution] A control device for a hybrid vehicle having an engine and an electric motor as power sources, enabling series hybrid driving and direct engine driving, and having a NOx purification system using an SCR catalyst and an LNT catalyst in the exhaust passage of the engine, comprising: an abnormality detection unit that detects abnormalities related to the NOx purification system using the SCR catalyst; and a driving state control unit that, when the abnormality is detected, prohibits direct engine driving as the driving mode of the vehicle and restricts it to series hybrid driving, and causes the engine to operate in a steady state so that the output is above a predetermined value within an output range where the NOx emissions from the engine do not exceed the NOx purification amount that can be purified by the NOx purification system using the LNT catalyst. [Selection Diagram] Figure 5

Inventors

  • 鎌倉 聖

Assignees

  • いすゞ自動車株式会社

Dates

Publication Date
20260511
Application Date
20241023

Claims (9)

  1. A control device for a hybrid vehicle having an engine and an electric motor as power sources, enabling series hybrid driving and direct engine-driven driving using these, and having a NOx purification system using an SCR catalyst and an LNT catalyst in the exhaust passage of the engine, An abnormality detection unit for detecting abnormalities in the NOx purification system using the aforementioned SCR catalyst, When the aforementioned abnormality is detected, the driving mode of the vehicle is restricted to the series hybrid mode, prohibiting the direct-drive mode, and the driving state control unit causes the engine to operate in a steady state so that the output from the engine is above a predetermined value within the output range, such that the NOx emissions from the engine do not exceed the NOx purification capacity of the NOx purification system using the LNT catalyst. A control device for hybrid vehicles equipped with [a specific feature/feature].
  2. The control device for a hybrid vehicle according to claim 1, wherein, when the driving state control unit detects the abnormality, it causes the engine to operate steadily in NOx reduction mode instead of fuel efficiency priority mode.
  3. The control device for a hybrid vehicle according to claim 2, wherein in the NOx reduction mode, the opening degree of the EGR valve of the engine is increased compared to the opening degree set in the fuel efficiency priority mode.
  4. The control device for a hybrid vehicle according to claim 1, wherein when the driving state control unit detects the abnormality, it causes the engine to operate at a steady state with the maximum output within the output range or an output that takes into account a margin over said maximum output.
  5. The control device for a hybrid vehicle according to claim 1, further comprising a rich spike execution control unit that causes the engine to execute a rich spike at any given time based on the NOx storage amount of the LNT catalyst.
  6. The control device for a hybrid vehicle according to claim 1, wherein, when the abnormality is detected, the driving state control unit uses the output of the engine to generate the power necessary for driving with the electric motor, and uses the output of the electric motor to satisfy the required driving force corresponding to the driver's accelerator operation.
  7. The aforementioned abnormality is a failure mode in which it is determined that the purification performance of the SCR catalyst cannot be ensured. The control device for a hybrid vehicle according to claim 1.
  8. The control device for a hybrid vehicle according to claim 7, wherein the abnormality includes a shortage of urea solution in the urea solution supply device that supplies urea solution to the SCR catalyst, and abnormal sensor values and operational abnormalities of the NOx sensor, temperature sensor, and NOx sensor disposed upstream and downstream of the SCR catalyst in the exhaust passage.
  9. A control method for a hybrid vehicle having an engine and an electric motor as power sources, enabling series hybrid driving and direct engine-driven driving using these, and having a NOx purification system using an SCR catalyst and an LNT catalyst in the exhaust passage of the engine, A process for detecting abnormalities in the NOx purification system using the aforementioned SCR catalyst, If the aforementioned abnormality is detected, the vehicle's driving mode is restricted to prohibiting direct-drive operation and to series hybrid operation, and the engine is operated in a steady state so that the output from the engine is above a predetermined value within the output range that does not exceed the amount of NOx that can be purified by the NOx purification system using the LNT catalyst. Control method for a hybrid vehicle.

Description

This disclosure relates to a control device for a hybrid vehicle and a control method for a hybrid vehicle. In recent years, the demand for improved energy efficiency and reduced exhaust emissions (NOx) has led to increasing diversification of hybrid vehicle configurations. For example, some recent hybrid vehicles are series/parallel hybrid vehicles that can switch between series and parallel driving modes. Generally, series hybrid vehicles are driven by electric motors. The engine is used solely for generating electricity; the power generated by the generator, powered by the engine, is either used to charge the battery or supplied to the electric motors. Series hybrid vehicles have two driving modes: "EV driving mode" and "series driving mode." In EV driving mode, the hybrid vehicle is driven by the power of an electric motor powered by the battery. The engine is not driven in this mode. In series driving mode, the hybrid vehicle is driven by the power of an electric motor powered by electricity supplied from both the battery and the generator, or from the generator alone. In this mode, the engine is driven to generate electricity in the generator. Series driving mode is useful because it allows the engine to operate steadily near its optimal fuel efficiency point. Parallel hybrid vehicles are driven by either the electric motor or the engine, or both. Specifically, the mode in which a parallel hybrid vehicle is driven solely by the engine is called the "engine driving mode." Furthermore, the mode in which a parallel hybrid vehicle is driven by both the engine and the electric motor is called the "parallel driving mode." Both engine driving mode and parallel driving mode are useful because they can suppress battery charging and discharging losses, as well as various resistance losses when operating the electric motor and/or generator. Series/parallel hybrid vehicles employ a configuration that combines both of the above methods. Specifically, in this system, the power transmission system switches between series and parallel configurations by disengaging or engaging (disengaging) a clutch depending on the driving conditions of the hybrid vehicle. Series/parallel hybrid vehicles are useful because they allow the driver to enjoy the advantages of both series and parallel hybrid vehicles. Furthermore, in order to improve exhaust emissions (NOx) in such hybrid vehicles, it is necessary to optimize the operation of the entire vehicle, including the control of both the engine and the electric motor (see, for example, Patent Documents 1 and 2). Japanese Patent Publication No. 2020-050009Japanese Patent Publication No. 2019-166943 Diagram showing the conventional engine control method when the SCR system malfunctions.A schematic diagram showing the overall configuration of a vehicle according to one embodiment of the present invention.A diagram showing an example of the configuration of an exhaust gas purification device according to one embodiment of the present invention.A diagram showing an example of the functional configuration of an ECU according to one embodiment of the present invention.A diagram showing the mode of engine control by the ECU during an SCR system malfunction according to one embodiment of the present invention.This figure shows an example of a control map for controlling the valve opening of an EGR device by an ECU according to one embodiment of the present invention.A flowchart illustrating an example of the operation of the SCR system anomaly detection function of an ECU according to one embodiment of the present invention. Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same function are denoted by the same reference numerals, thus omitting redundant explanations. <Overall vehicle configuration> The following describes an example of the configuration of a hybrid vehicle (hereinafter referred to as "Vehicle 1") according to one embodiment of the present invention. Vehicle 1 according to this embodiment is a series/parallel hybrid vehicle that combines a series system and a parallel system. Figure 2 is a schematic diagram showing the overall configuration of vehicle 1. Vehicle 1 comprises a battery 10, an electric motor 20, an engine 30, a generator 40, a clutch 50, a gear mechanism 60, an exhaust gas purification device 70, various sensors 80, and an ECU 100. Battery 10 is a lithium-ion battery that supplies a high voltage, for example, 200-350V. Battery 10 is wired to the electric motor 20, allowing it to supply power to the motor 20. Furthermore, battery 10 is wired in parallel to the electric motor 20 to the generator 40, allowing it to charge itself with power generated by the generator 40. The electric motor 20 generates power for the vehicle 1 to move using the electricity charged in the battery 10 and/or the electricity generated by th