Engine Upshift Energy Recovery Using Electric Machine Torque Control
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Solution Overview
Problem
Internal combustion engines waste rotational energy during upshifts, which is converted into heat rather than being recovered as kinetic energy, leading to inefficient energy use and increased emissions.
Innovation Solution
A method that reduces the speed of the internal combustion engine during upshifts and converts the kinetic energy into electrical energy using an electric machine, by applying excessive torque with a clutch and negative torque to the electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the combustion engine speed is reduced during upshift to recover energy, then energy efficiency is improved, but the engine torque control becomes more complex
Solution Approach 1:
The patent converts the harmful effect of engine deceleration during upshift (which normally causes energy loss and requires torque reduction) into a beneficial energy recovery opportunity. By controlling the electric machine to generate electricity during engine deceleration, the system transforms what was previously a waste energy scenario into a useful energy recovery process, improving overall energy efficiency without requiring additional hardware beyond the existing electric machine.
Solution Approach 2:
The electric machine serves multiple functions: it acts as a motor for assist torque during acceleration, a generator for energy recovery during deceleration and upshifts, and a torque decoupling device during gear transitions. This multi-functionality allows the system to recover energy during upshifts without adding dedicated hardware, thereby managing complexity while improving energy efficiency.
2Force
If artificial combustion impairment is used to reduce engine torque during upshift, then dynamic torque reduction is achieved, but emissions worsen
Solution Approach 1:
Instead of artificially impairing combustion to reduce torque (which worsens emissions), the patent uses the electric machine to provide or reduce torque electrically. This allows precise torque control during upshift without disrupting the combustion process, thereby avoiding increased emissions while still achieving the necessary dynamic torque reduction for smooth gear transitions.
Solution Approach 2:
The patent replaces the mechanical/combustion-based torque control method with an electrical torque control method. Rather than adjusting ignition angle or throttle position to reduce torque (which impairs combustion), the system uses the electric machine to electrically adjust torque output, providing cleaner and more precise control that avoids emission penalties.
3Loss of energy
If the electric machine is used to control engine speed during upshift, then energy recovery is improved, but the torque transfer control becomes more complex
Solution Approach 1:
The electric machine performs multiple roles simultaneously: it decouples torque during clutch engagement, provides or absorbs torque to control engine speed, and generates electricity during deceleration. This multi-functionality consolidates control complexity into a single existing component rather than requiring multiple dedicated devices, improving energy recovery while managing system complexity.
Solution Approach 2:
The electric machine acts as an intermediary between the engine and transmission during upshifts. It mediates the torque and speed transitions by electrically adjusting engine speed and providing torque smoothing, thereby simplifying the overall control strategy compared to direct mechanical torque transfer control while improving energy recovery efficiency.
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 method effectively recovers kinetic energy that would otherwise be lost as heat, improving energy efficiency and reducing emissions by converting it into electrical energy for later use.
Implementation Method 1
converting the kinetic energy of the rotation of the internal combustion engine or a drive unit into electrical energy by at least one electrical machine
Data Source
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AI summary
The invention relates to a method for recovering kinetic energy from a combustion engine (VM) by reducing the speed of the combustion engine (VM) for a predetermined time (t) during changing up of a gearbox (14) in a vehicle and converting the kinetic energy of the rotation of the combustion engine (eng_spd) or of a drive unit into electrical energy by at least one electric motor (EM, 13).