Hybrid Vehicle Clutch Engagement Control via Torque Synchronization
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Solution Overview
Problem
Conventional hybrid vehicle control methods experience impact on the clutch during mode conversion from EV to HEV, leading to prolonged torque blending time and degraded fuel efficiency due to zero-torque engine control.
Innovation Solution
A control method that determines the accelerator pedal change amount to initiate engine startup via the Hybrid Shaft Generator (HSG), outputs constant torque from the engine, and synchronizes engine torque with motor torque to engage the clutch, using a control portion to manage engine, HSG, motor, battery, and clutch operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine speed is synchronized with motor speed while engine is zero-torque controlled for a predetermined period of time, then engine torque can be synchronized with motor torque, but impact is applied to the clutch according to engine torque and torque blending time is lengthened
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing engine speed with motor speed before clutch engagement, and by pre-adjusting engine torque to match motor torque requirements. The control portion calculates target engine torque based on motor torque and gradually increases engine torque from zero to the target value during the synchronization period, rather than waiting for full speed synchronization before torque application. This preliminary torque adjustment reduces the time needed for torque blending after engagement while preventing clutch impact.
Solution Approach 2:
The patent implements dynamics by continuously adjusting engine torque as a dynamic variable during the synchronization process. The control portion dynamically modifies engine torque commands based on real-time comparisons between engine and motor speeds, and between actual and target torque values. This dynamic torque adjustment allows the system to adapt the synchronization process to actual operating conditions, reducing both synchronization time and clutch impact compared to fixed zero-torque control.
2Reliability
If engine is zero-torque controlled for a predetermined period of time, then engine speed can be synchronized with motor speed, but fuel efficiency of the vehicle is degraded
Solution Approach 1:
The patent applies preliminary action by beginning torque buildup during the synchronization process rather than waiting for speed alignment. The control portion starts applying small engine torque commands immediately after synchronization initiation and gradually increases them to the target value. This allows the engine to contribute to propulsion during the synchronization period, improving fuel efficiency while still achieving accurate speed synchronization through continuous speed monitoring and adjustment.
Solution Approach 2:
The patent implements continuity of useful action by maintaining continuous engine torque application throughout the synchronization process. Instead of zero-torque control, the engine provides continuous useful work by delivering gradually increasing torque that matches the motor torque profile. This continuous useful action ensures the engine remains an active power source during mode transition, improving overall fuel efficiency while achieving the necessary speed synchronization through coordinated control.
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 approach minimizes torque blending time and enhances fuel efficiency by supplying engine torque through the HSG, reducing battery power consumption and optimizing engine control for rapid torque synchronization.
Implementation Method 1
starting up an engine through a Hybrid Shaft Generator (HSG) during conversion into an HEV mode from an EV mode
Implementation Method 2
a battery charged with the electrical energy generated by the HSG and the motor
Implementation Method 3
a motor supporting the power of the engine and functioning as a generator during braking to generate electrical energy
Implementation Method 4
the engine for combusting fuel to generate power
Data Source
AI summary
A control method of a hybrid vehicle may include performing a series of commands by a control portion including determining whether an accelerator pedal change amount detected by an accelerator pedal sensor is greater than a predetermined value, starting up an engine through a Hybrid Shaft Generator (HSG) during conversion into an HEV mode from an EV mode, controlling the engine to output constant torque, and synchronizing engine torque with motor torque to engage a clutch.