Starter Motor Torque Modulation for Engine Starting

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Internal combustion engines require a large starting torque, especially in cold conditions or after a long inactive period, which leads to increased costs, weight, and installation space for conventional starter motors, and hybrid vehicles face challenges with weak electric machines unable to provide sufficient torque for starting.

Innovation Solution

A method and device that modulate the starting torque between positive and negative values as a function of time, allowing the starter motor to reverse the direction of the crankshaft's rotational movement during the starting process, utilizing the dynamic behavior of the mechanical system to amplify the starter motor's effect and reduce the maximum starting torque required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional starter motor is used to provide sufficient starting torque, then the engine can start reliably even in cold conditions, but the starter motor's weight, cost, and installation space increase

Engineering Contradiction:

Improvestarting reliabilityVSAvoidstarter motor weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The starter motor operates dynamically by switching between motor mode and generator mode during the starting process. The control unit modulates the starting torque between positive and negative values as a function of time, allowing the system to adapt its behavior based on the instantaneous needs of the starting process rather than relying on a constantly high torque output.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control unit applies periodic modulation of the starting torque, switching between positive and negative torque values. This periodic action allows the starter motor to deliver high average torque over time while maintaining lower peak torque requirements, enabling the use of a smaller, lighter motor.

Inventive Principle:

Principle #19Periodic action

2Force

If a larger starting torque is provided by the starter motor, then the breakaway torque and sliding friction can be overcome more effectively, but the device complexity and cost increase

Engineering Contradiction:

Improvestarting torqueVSAvoidstarter system complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The starter motor performs multiple functions: it acts as a motor during the acceleration phase, as a generator during the deceleration phase, and provides both positive and negative torque control. This multi-functionality eliminates the need for separate components and simplifies the overall system architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control unit changes the operational parameters of the starter motor by switching between motor and generator modes and modulating the torque between positive and negative values. This parameter modulation allows the system to achieve high starting torque effectiveness without requiring a larger motor.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the starter motor continuously applies high torque to ensure engine starting, then the starting process is reliable, but energy consumption increases

Engineering Contradiction:

Improvestarting reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #19Periodic action

4Weight of moving object

If a smaller starter motor is used to reduce weight and cost, then the installation space and cost decrease, but sufficient starting torque cannot be provided in cold conditions

Engineering Contradiction:

Improvestarter motor weightVSAvoidstarting torque

Core Design Contradiction:

Weight of moving objectVSForce

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8720401B2Method and device for starting an internal combustion engine

Publication Date: 2014.05.13 VOLKSWAGEN AG

AI summary

A method and a device for starting an internal combustion engine of a motor vehicle, the internal combustion engine exerting a drive torque on a crankshaft in one direction of the internal combustion engine, a starting motor exerting a starting torque on the crankshaft during a starting process to achieve a minimum rotational speed of the internal combustion engine, and a control unit regulating the starting torque. The control unit regulates the starting torque in a time-dependent manner between a positive maximum starting torque and a negative minimum starting torque during the starting process, a positive starting torque acting on the crankshaft in one direction and a negative starting torque in the opposite direction.