Motor Vehicle Drive Clutch Torque Control for Energy-Efficient Mode Switching

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for switching from sailing operation to thrust operation in a motor vehicle drive unit are energy-intensive and result in increased fuel consumption.

Innovation Solution

Engage the clutch during the switch from sailing mode to overrun mode while simultaneously controlling the idle speed of the internal combustion engine, using clutch torque as a control variable to regulate the engine speed to match the transmission speed, and partially engage the clutch to minimize frictional work.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional drive device with mechanical friction-based components is used, then propulsion force is generated, but wear and tear occur reducing reliability and increasing maintenance needs

Engineering Contradiction:
ImprovereliabilityVSAvoidwear resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent replaces mechanical friction-based propulsion with a magnetic field-based propulsion system. The drive device generates a magnetic field that interacts with the drive shaft, eliminating mechanical contact and friction. This substitution of mechanical principles with magnetic field principles resolves the contradiction by providing reliable propulsion without wear and tear, as magnetic fields do not degrade through use like mechanical components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex control algorithms are implemented to manage magnetic field interactions, then drive accuracy is improved, but computational load and processing time increase

Engineering Contradiction:
Improvedrive accuracyVSAvoidcomputational processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-calculates and stores optimal control parameter mappings in lookup tables during the design phase. During operation, the controller simply retrieves pre-computed values based on current operating conditions rather than performing complex real-time calculations. This preliminary action resolves the contradiction by providing accurate drive control through pre-computed optimal parameters while minimizing real-time computational load and processing time.

Inventive Principle:
Principle #10Preliminary action

3Power

If the magnetic drive system operates at higher power levels, then propulsion force increases, but eddy current losses and heat generation increase

Engineering Contradiction:
Improvepropulsion forceVSAvoideddy current losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent employs segmented magnets arranged in alternating polarity patterns around the drive shaft, creating localized magnetic fields rather than a single large field. This segmentation approach allows the system to achieve high propulsion force through coordinated local field interactions while minimizing eddy current losses, as the alternating polarity and segmented structure reduce circulating currents in conductive materials. The local quality principle resolves the contradiction by distributing power generation across multiple localized zones rather than requiring a single high-power field.

Inventive Principle:
Principle #3Local quality

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 reduces fuel consumption during the switching process by eliminating the need for additional acceleration fuel and minimizing clutch friction, resulting in a more energy-efficient transition.

Implementation Method 1

a magnetic field is generated in a magnetic field region which extends in the circumferential direction over at least part of the circumference of the drive shaft viewed in the axial direction. In order to propel the motor vehicle, a magnetic drive force is generated from the magnetic field acting on the drive shaft

Methodology Applied
Scientific EffectMagnetic field interaction: Lorentz Force

Data Source

PatentEP3277552B1Method for operating a drive device for a motor vehicle and corresponding drive device
Publication Date: 2022.09.28 AUDI AG
  • EP3277552B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for operating a drive device (1) for a motor vehicle, wherein the drive device (1) comprises an internal combustion engine (2), an output shaft and a clutch (6) connected between the internal combustion engine (2) and the output shaft, and wherein in a coasting mode an idle-running control of the internal combustion engine (2) is guided to an idling speed and the clutch (6) is opened, and in an overrun mode the clutch (6) is closed. When there is a switching from the coasting mode into the overrun mode when the idle-running control of the internal combustion engine (2) is simultaneously guided to the idling speed, the clutch (6) is closed so that the internal combustion engine (2) is tow-started. The invention further relates to a drive device (1) for a motor vehicle.