Hybrid Vehicle Engine Abnormality Control via Motor Motoring
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Solution Overview
Problem
Conventional hybrid vehicles face secondary malfunctions when an abnormality occurs in the internal combustion engine, particularly at high speeds, due to rapid changes in engine rotation speed, which can lead to issues in the planetary gear mechanism.
Innovation Solution
A hybrid vehicle control method that determines the presence of engine-related abnormalities and employs normal or high-speed evasive electric travel control to manage power output from the second motor, either by halting the internal combustion engine or motoring it using the first motor to maintain a target rotation speed, thereby suppressing rapid rotation speed changes and secondary malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is stopped suddenly to prevent secondary malfunctions, then the planetary gear mechanism is protected, but the vehicle loses the ability to maintain stable power output from the engine
Solution Approach 1:
The control device merges the power output functions of the engine and first motor during abnormality conditions. Instead of relying solely on the engine for power output, the system combines the engine's power with the first motor's power, allowing the first motor to compensate for the engine's reduced or unstable power output. This merging ensures stable total power delivery to the drive shaft while the engine is recovering from or operating under abnormal conditions.
2Reliability
If the first motor is used to motor the engine shaft at a target rotation speed, then rapid rotation speed changes are suppressed, but the power consumption of the first motor increases
Solution Approach 1:
The control device applies partial action by using the first motor only to the extent necessary to prevent harmful rotation speed changes in the planetary gear mechanism. Instead of continuously operating the first motor at full capacity, the system activates the first motor specifically during abnormality conditions when rotation speed stability is critical, and adjusts the first motor's output to provide just enough counteracting torque to maintain stable rotation speeds without excessive power consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the hybrid vehicle to continue traveling while minimizing secondary malfunctions in the planetary gear mechanism by controlling engine rotation speed, reducing power consumption, and extending travel using power from the second motor.
Implementation Method 1
a first motor capable of inputting and outputting power... when the vehicle speed obtained by the vehicle speed acquisition device equals or exceeds the predetermined vehicle speed... high vehicle speed evasive electric travel control, in which the traveling power is output to the drive shaft from the second motor while the internal combustion engine is motored by the first motor
Implementation Method 2
a second motor capable of outputting power to the drive shaft... when the vehicle speed obtained by the vehicle speed acquisition device is lower than a predetermined vehicle speed... normal evasive electric travel control, in which a traveling power is output to the drive shaft from the second motor while the internal combustion engine is halted
Implementation Method 3
a planetary gear mechanism that includes a first element connected to a rotary shaft of the first motor, a second element connected to an engine shaft of the internal combustion engine, and a third element connected to a drive shaft that transmits power to a drive wheel... the three elements being capable of mutual differential rotation
Implementation Method 4
a storage device capable of exchanging power with the first and second motors
Data Source
AI summary
The invention provides a hybrid vehicle and a control method thereof with which, in a case where a vehicle speed V obtained by a vehicle speed sensor equals or exceeds a first determination vehicle speed V1 at a time of occurrence of an internal combustion engine-related abnormality, which is when an abnormality relating to motors MG1 and MG2 is determined not to have occurred but an abnormality relating to an engine is determined to have occurred while the engine is operative, the motors MG1 and MG2 are controlled such that traveling torque is output to a ring gear shaft serving as a drive shaft from the motor MG2 while the engine is motored by the motor MG1 such that a crankshaft rotates at a target rotation speed until the vehicle speed V subsequently falls to or below a second determination vehicle speed V2.