Electric Machine Torque Control for Engine Flare During Gear Shift
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Solution Overview
Problem
Hybrid vehicle transmission systems experience inefficiencies and reduced driveability due to complex clutch control mechanisms that engage and disengage during power distribution, leading to engine flare issues during gear shifts.
Innovation Solution
A control strategy using a controller to adjust electric machine current and torque, applying negative motor torque to manage engine speed and acceleration, combining closed-loop control with feed-forward compensation to match engine speed to target values set by gear ratios and output shaft speeds, thereby preventing engine flare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If clutch control mechanisms are used to manage power distribution during gear shifts, then power distribution control is achieved, but device complexity increases and driveability is reduced
Solution Approach 1:
The patent extracts the flare control function from the complex clutch control system by introducing a dedicated flare control mechanism that operates independently. The controller separately manages clutch operations and flare prevention, removing the burden of dual-function complexity from the clutch control system while maintaining effective power distribution control.
Solution Approach 2:
The control system is segmented into distinct functional modules: clutch control for power distribution and flare control for engine speed management. This segmentation allows each module to operate independently with optimized control strategies, reducing overall system complexity while maintaining adaptability in power distribution.
2Object-affected harmful factors
If traditional methods like retarding spark or throttle control are used to manage engine flare, then engine flare is reduced, but fuel economy and emissions are negatively affected
Solution Approach 1:
The patent introduces the electric machine as an intermediary device between the engine and transmission to control engine flare. Instead of directly affecting combustion parameters (spark timing or throttle), the electric machine acts as a mediator by applying electromagnetic torque to the engine crankshaft, smoothly controlling engine speed without disrupting the combustion process and thus preserving fuel economy and emissions performance.
Solution Approach 2:
The patent replaces traditional mechanical/combustion-based flare control methods (spark retardation, throttle adjustment) with an electromagnetic control mechanism. The electric machine uses electromagnetic fields to generate torque, substituting the need for combustion parameter adjustments and providing a more efficient, non-intrusive method of engine speed control that does not compromise fuel economy or emissions.
3Adaptability or versatility
If clutch engagement and disengagement is used during power distribution adjustment, then power distribution flexibility is improved, but driveability is reduced
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors engine speed, transmission state, and clutch position. Based on this feedback, the controller dynamically adjusts clutch engagement timing and electric machine torque application to maintain smooth power transfer. This feedback loop ensures that clutch operations are optimized for both power distribution flexibility and driveability, preventing harsh engagements that would degrade driver experience.
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 effectively reduces engine flare by rapidly adjusting electric motor torque, improving shift quality and avoiding the negative impacts of traditional methods like retarding spark or throttle control, which affect fuel economy and emissions.
Implementation Method 1
A control strategy using a controller to adjust electric machine current and torque, applying negative motor torque to manage engine speed and acceleration
Data Source
AI summary
A vehicle includes an engine, an electric machine, a transmission, and at least one controller. The at least one controller, in response to a gear shift of the transmission that causes a speed of the engine to exceed a predetermined speed, commands a change in current to the electric machine such that the speed of the engine decreases to a target speed to avoid engine flare.