Belt Starter-Generator Torque Ramping for Smooth Engine Restart

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing automatic stop/restart systems for thermal engines in vehicles cause significant torque variation during start-up, leading to acoustic effects that are annoying for users and potentially damage the belt transmission, while existing solutions fail to effectively minimize these issues.

Innovation Solution

A method and device that utilize a rotating electric machine with a drive member and transmission member, where a predetermined reduced torque is applied for a controlled duration to pre-tension the belt, followed by an optimal torque to quickly start the engine, using a control system that accounts for rotation speed, excitation current, inverter angle, and temperature to minimize torque variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a high torque is provided by the rotating electrical machine to quickly start the engine, then the start-up delay is reduced, but the transmission member (belt) is damaged due to excessive tension

Engineering Contradiction:

Improvestart-up delayVSAvoidtransmission member integrity

Core Design Contradiction:

Loss of timeVSStrength

Solution Approach 1:

The starting process is divided into multiple phases: a first phase with reduced torque to tension the belt, followed by a second phase with optimal torque to cross the compression point. This segmentation prevents belt damage while achieving quick engine start

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Before applying high torque to start the engine, the system first applies a predetermined reduced torque for a predetermined duration to tension the transmission member. This preliminary action prepares the belt to withstand the subsequent high torque without damage

Inventive Principle:

Principle #10Preliminary action

2Strength

If the preflux step duration is limited to protect the belt, then the transmission member is protected, but acoustic effects are generated due to sudden torque variation

Engineering Contradiction:

Improvetransmission member protectionVSAvoidacoustic effects

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the torque profile based on real-time conditions. The control system monitors parameters and modifies the torque application to maintain belt tension protection while minimizing sudden torque variations that cause acoustic effects

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (torque magnitude, duration, and rate of change) to achieve a balance between protecting the transmission member and minimizing acoustic effects. The predetermined reduced torque and duration are optimized to prevent belt damage while reducing torque shock

Inventive Principle:

Principle #35Parameter changes

3Strength

If a predetermined reduced torque is applied to tension the transmission member, then the belt is protected from damage, but the engine start-up delay increases

Engineering Contradiction:

Improvetransmission member protectionVSAvoidstart-up delay

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The system applies a partial torque (predetermined reduced torque) for a specific duration to achieve belt tensioning, then transitions to optimal torque. This partial action approach protects the belt while minimizing the time penalty through optimized duration

Inventive Principle:

Principle #16Partial or excessive action

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 start-up time while minimizing acoustic effects and belt damage, ensuring a smooth and efficient engine start without excessive torque variation.

Implementation Method 1

a rotating electrical machine, in particular an alternator-starter, supplied in a starting mode by an inverter

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the rotating electrical machine supplies a predetermined reduced torque in the starting direction... and supplies a predetermined optimum torque to quickly drive the heat engine

Methodology Applied

Scientific EffectElectromagnetic torque generation: Electromagnetic Induction

Data Source

PatentEP3158635B1Method and device for starting or for restarting a heat engine, particularly of a motor vehicle

Publication Date: 2024.07.31 VALEO ELECTRIFICATION

Figure 1
Figure 2
Figure 3a~3b

AI summary

The method according to the invention calls upon a rotary electric machine (1) comprising a drive member (3) and a transmission member (4) of the belt or chain type, collaborating with the drive member and with the combustion engine (2) in order to start or restart the combustion engine, a tensioner (6) being provided to press against one strand (7) of the transmission member that extends between the rotary electric machine and the combustion engine. According to the invention, in a first stage, the rotary electric machine (1) supplies a predetermined reduced torque in the direction of starting for a predetermined duration in order to tension the transmission member (4) and then, in a second stage, the rotary electric machine (1) supplies a predetermined optimum torque for rapidly turning over the combustion engine (2) and causing it to start.