Hybrid Vehicle Power Split Mechanism Engine Speed Control
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Solution Overview
Problem
In hybrid vehicles, engine rotation speed increase control is delayed due to noise vibration (NV) restriction regions, leading to deteriorated acceleration responsiveness when the motor generator does not output reaction force torque.
Innovation Solution
A hybrid vehicle configuration with a power split mechanism including an input element connected to the engine, a reaction force element connected to the rotating electric machine, and an output element connected to the drive wheel, allowing the rotating electric machine to output reaction force torque to support engine torque during engine rotation speed increase control, and optionally using a supercharger to enhance engine torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If engine torque limitation due to NV requirement is applied, then noise vibration is suppressed, but engine rotation speed increase is delayed and acceleration responsiveness deteriorates
Solution Approach 1:
The patent applies dynamics by making the NV restriction dynamically adjustable rather than static. The ECU temporarily relaxes or cancels the NV restriction when engine rotation speed increase control is detected, allowing the system to adapt its constraints based on operational conditions. This resolves the contradiction by enabling high speed increase when needed while maintaining NV suppression during normal operation.
Solution Approach 2:
The patent changes the NV restriction parameter from a fixed limitation to a variable constraint that can be relaxed or canceled. By modifying the torque limitation parameter based on whether engine rotation speed increase control is active, the system allows rapid speed increase when required while maintaining noise vibration suppression under normal conditions.
2Object-affected harmful factors
If engine torque limitation due to NV requirement is applied, then noise vibration is suppressed, but acceleration responsiveness deteriorates
Solution Approach 1:
The system dynamically adjusts NV restrictions based on acceleration demands. When acceleration responsiveness is prioritized (engine rotation speed increase control active), the NV restriction is temporarily relaxed or canceled, reducing the time loss during acceleration while maintaining NV suppression during steady-state operation.
Solution Approach 2:
The system detects engine rotation speed increase control in advance and proactively relaxes or cancels NV restrictions before they would hinder acceleration performance. This preliminary adjustment ensures responsive acceleration without incurring time delays.
3Adaptability or versatility
If rotating electric machine does not output reaction force torque, then motor generator can operate freely, but engine rotation speed increase control cannot be executed effectively
Solution Approach 1:
The system uses feedback by detecting whether the rotating electric machine is outputting reaction force torque and adjusting engine torque accordingly. When rotation speed increase control is needed and reaction force torque is unavailable, the ECU relaxes NV restrictions to enable effective engine rotation speed increase, creating a closed-loop control system that adapts to real-time operational conditions.
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
This configuration suppresses the delay in engine rotation speed increase due to NV restrictions by relaxing engine torque limitations, improving acceleration responsiveness.
Implementation Method 1
the engine may include a supercharger, and an output torque of the engine may be increased by operating the supercharger
Data Source
AI summary
A hybrid vehicle including: an engine; output member that transmits driving force to drive wheels; a rotating electric machine; and a power split mechanism that splits and transmits the driving force output from the engine to the output member and the rotating electric machine, the mechanism including at least three rotating elements of an input element connected to the engine, a reaction force element connecting the rotating electric machine, and an output element connecting the output member, the machine capable of outputting reaction force torque to required engine torque based on an acceleration request to apply torque to the required engine torque to the drive wheel, where the machine does not output the reaction force torque, engine rotation speed increase control being able to be executed, engine torque limitation due to a NV requirement being able to be executed and which is relaxed during the engine rotation speed increase control.