Starter-Generator Modes for Low-Fatigue Engine Starting

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Solution Overview

Problem

Manual starting of recreational vehicle engines through recoil starters can cause user fatigue due to the need for fast and repetitive pulling of the rope, and existing electric start systems may not efficiently manage power levels for optimal starting modes.

Innovation Solution

A starter-generator system that determines available starting modes based on power source health, offering full-starting, pull-assist, and manual starting modes, and includes a hybrid battery system with a DC/DC converter, supercapacitor, and lithium-ion battery for efficient power management and cranking assist.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual pull starting is used, then the system is simple and reliable, but user fatigue increases due to repetitive fast pulling

Engineering Contradiction:
Improveuser fatigueVSAvoidstarting system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the purely mechanical pull-start system with an electric motor-assisted starting system. The electric motor provides cranking torque to assist or replace manual pulling, reducing user fatigue while maintaining starting capability. The controller manages the electric motor activation based on detected starting conditions, seamlessly integrating electrical assistance with the mechanical starting process.

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

Solution Approach 2:

The starting system is designed to perform multiple functions: it can operate in pure manual pull mode, electric motor-assist mode, or pure electric motor mode depending on the situation. This multi-functionality allows the system to adapt to different user needs and conditions, providing fatigue reduction when needed while maintaining simplicity when the electric system is not required.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If electric start system is added, then user fatigue is reduced, but power management complexity increases

Engineering Contradiction:
Improvestarting effortVSAvoidpower management complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent incorporates a controller that continuously monitors system parameters such as battery power levels, motor status, and starting progress. Based on this feedback, the controller dynamically adjusts the operation mode, managing power distribution between the battery, electric motor, and engine starting components. This feedback mechanism automates power management decisions, reducing the perceived complexity for the user while maintaining efficient power utilization.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The power management system operates autonomously, with the controller automatically determining when to activate the electric motor, how much power to draw from the battery, and when to transition between starting modes. This self-service capability eliminates the need for manual power management interventions, simplifying the user interface while handling the underlying complexity internally.

Inventive Principle:
Principle #25Self-service

3Reliability

If hybrid battery system is used, then starting reliability at low temperatures is improved, but system weight increases

Engineering Contradiction:
Improvestarting reliability at low temperatureVSAvoidbattery system weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs a hybrid battery system combining two different battery technologies, each selected for its superior performance in specific conditions. One battery type provides reliable power delivery in cold temperatures, while the other complements it with additional capacity or different operational characteristics. This composite approach leverages the strengths of different materials and chemistries to achieve reliable starting across a wide temperature range while managing overall system weight through optimized selection and sizing of each battery component.

Inventive Principle:
Principle #40Composite materials

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

Reduces user fatigue by providing alternative starting modes and efficient power management, ensuring reliable engine starts even at low temperatures, with reduced weight and improved performance.

Implementation Method 1

a supercapacitor system configured to provide electric power to the engine during engine starting at low temperature

Methodology Applied
Scientific EffectElectrostatic energy storage: Capacitance

Implementation Method 2

a lithium-ion battery removably connected to the vehicle and configured to pre-charge the supercapacitor system when the engine is not running

Methodology Applied
Scientific EffectElectrochemical energy conversion: Battery (electricity)

Implementation Method 3

a DC/DC converter

Methodology Applied
Scientific EffectElectrical power conversion: Electromagnetic Induction

Data Source

PatentEP4402359B1Systems and methods for engine start
Publication Date: 2026.01.21 POLARIS IND INC
  • EP4402359B1 patent drawingFigure 1
  • EP4402359B1 patent drawingFigure 2
  • EP4402359B1 patent drawingFigure 3

AI summary

Systems and methods for starting and restarting an engine of a vehicle are disclosed. Power systems for an engine are disclosed.