Hybrid Vehicle Start Control Device for EV Reverse Starting
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Solution Overview
Problem
Conventional start control devices for hybrid vehicles risk starting in the forward direction instead of reverse during EV reverse starting due to abnormalities in the electronic control system, leading to unintended power transmission from the internal combustion engine to the drive wheels.
Innovation Solution
A start control device with a select operation mechanism that locks engagement clutches in a neutral position, preventing the selection of ICE gear shift stages during EV reverse starting, ensuring the electric motor rotates opposite to the internal combustion engine's direction, thus maintaining a torque transmission cutoff and ensuring intended EV reverse starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power interrupting means is kept in a disconnected state during EV reverse starting, then electricity can be generated by driving the electric motor with the internal combustion engine, but if the power interrupting means is stroked due to electronic control system abnormality, the drive wheels and internal combustion engine will transition to the engaged state, causing unintended forward starting
Solution Approach 1:
The power interrupting means is divided into a first power interrupting means (first engagement clutch) and a second power interrupting means (second engagement clutch). By segmenting the power interruption function into two separate clutches, the system can more reliably control the disconnection state during EV reverse starting, preventing unintended engagement even if one clutch experiences control abnormalities.
2Adaptability or versatility
If engagement clutches are provided to switch between EV gear shift stage and ICE gear shift stage, then gear selection is enabled, but electronic control system abnormalities may cause incorrect engagement, leading to unintended power transmission
Solution Approach 1:
Different engagement clutches are assigned to different power transmission paths: the first engagement clutch controls the ICE power transmission path, while the second engagement clutch controls the EV power transmission path. This local differentiation ensures that even if one clutch malfunctions, the other can maintain proper power transmission control for its designated path.
3Reliability
If a select operation mechanism is added to prevent ICE gear shift stage selection during EV reverse starting, then unintended forward starting is prevented, but device complexity increases
Solution Approach 1:
The select operation mechanism merges the control functions of multiple engagement clutches into a single coordinated system. By combining the control of the first and second engagement clutches under a unified select operation mechanism, the system prevents unintended ICE gear selection during EV reverse starting while avoiding the need for completely separate control systems for each clutch.
Data Source
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AI summary
To provide a start control device for a hybrid vehicle that ensures an EV reverse starting intended by a driver, even when an engagement command is issued to an engagement clutch that selects an ICE gear shift stage, when carrying out the EV reverse starting. A first motor/generator (MG1), an internal combustion engine (ICE), and a multistage gear transmission (1) are provided. In this hybrid vehicle, the multistage gear transmission (1) is provided with a third electric actuator (33) that selects an EV gear shift stage, and a first electric actuator (31) and a second electric actuator (32) that select an ICE gear shift stage. A transmission control unit (23) is provided, which causes the third electric actuator (33) to select EV 1st of the multistage gear transmission (1) at the time of starting, and that carries out an EV starting using the first motor/generator (MG1) as the drive source. The transmission control unit (23) is configured as a mechanism that prevents the selection of the ICE gear shift stage by the first electric actuator (31) and the second electric actuator (32) at the time of an EV reverse starting, and rotates the first motor/generator (MG1) in a direction opposite to the forward direction of rotation of the internal combustion engine (ICE).