Processor-Based Ignition Interface for Lawn Care Safety Switch Monitoring

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Solution Overview

Problem

Conventional ignition systems for lawn care vehicles, particularly riding mowers, lack advanced user interfaces and fail to effectively monitor both states of safety switches, which can lead to missed fault conditions and potential operator or equipment safety issues.

Innovation Solution

An electronic ignition system with a processor-based ignition interface that monitors both states of safety switches, such as seat presence and PTO switches, using a common pull-up voltage monitoring component to ensure accurate status detection and reduce complexity, cost, and heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional key operated switch system is used for ignition control, then the device complexity is reduced and manufacturing cost is lowered, but the user interface functionality is limited and safety monitoring capability is insufficient

Engineering Contradiction:
Improveuser interface functionalityVSAvoidignition system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The ignition interface is designed to perform multiple functions: it serves as a user interface for starting the engine, a monitoring system for safety switches, and a control system for ignition timing. The processor-based interface can detect both open and closed states of switches, providing versatile functionality while integrating what would traditionally require separate systems into a single unified component.

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

2Reliability

If traditional switch monitoring methods are used that only detect one state, then the device complexity is minimized, but fault detection capability is reduced and safety risks increase

Engineering Contradiction:
Improvesafety monitoring accuracyVSAvoidswitch monitoring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements feedback by continuously monitoring the state of safety switches and using this information to control ignition timing and provide operator feedback. The processor reads switch states and adjusts system operation accordingly, creating a closed-loop control system that improves reliability while maintaining manageable complexity through intelligent processing.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple separate monitoring components are used for different switch states, then measurement precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveswitch status detection accuracyVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple monitoring functions into a single processor-based ignition interface. Instead of using separate components for detecting open and closed states of safety switches, the system integrates these functions into one unified interface that can read multiple switch states through a single data bus connection, reducing overall system complexity while maintaining detection precision.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If a processor-based monitoring system is implemented to monitor both states of safety switches, then safety and performance are enhanced, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improveoperator safetyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The processor-based ignition interface is designed to perform multiple functions simultaneously: engine starting control, safety switch monitoring, ignition timing control, and operator feedback provision. By consolidating these functions into a single multi-functional component, the system enhances safety and performance while limiting the increase in manufacturing cost compared to implementing separate systems for each function.

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

Data Source

PatentEP3080912B1Ignition system for a lawn care device
Publication Date: 2021.01.20 HUSQVARNA AB
  • EP3080912B1 patent drawingFigure 1
  • EP3080912B1 patent drawingFigure 2
  • EP3080912B1 patent drawingFigure 3

AI summary

A lawn care device may include an engine to selectively power the lawn care device, a frame supporting the engine of the lawn care device, and an ignition interface having a processor therein to enable selective powering of the lawn care device based at least in part on operation of the ignition interface. The ignition interface may include a switch monitoring assembly configured to enable the processor to monitor status of a plurality of switches associated with respective components of the lawn care device. The switch monitoring assembly may be further configured to enable the processor to monitor opposing statuses (330, 332 or 324, 326) of at least one of the switches.