Two-Stroke Engine Control with Pressure and Temperature Feedback
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Solution Overview
Problem
Modern two-stroke internal combustion engines, especially those with boosting systems, suffer from underperformance, inefficiency, and poor emissions due to reliance on throttle valve position for engine control, which does not account for changes in engine inlet pressure and variation.
Innovation Solution
A method of controlling two-stroke engines by determining base nominal exhaust gas temperature, barometric pressure correction, exhaust gas temperature differential, and using these corrections for short-term fuel or ignition adjustments, combined with long-term corrections based on engine inputs and hours, to optimize engine performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If throttle valve position is used as the primary input for engine control, then the control system is simple to operate, but engine performance deteriorates due to lack of compensation for inlet pressure changes and engine variation
Solution Approach 1:
The patent implements feedback by continuously monitoring actual engine parameters (inlet pressure, exhaust gas temperature, engine speed) and using this information to dynamically adjust fuel injection and ignition timing. The ECU compares actual readings with expected values and applies corrections to optimize performance under varying conditions, resolving the contradiction between simple operation and reliable performance.
Solution Approach 2:
The system changes control parameters from solely throttle position to a multi-parameter approach including inlet pressure, exhaust gas temperature, and engine speed. By monitoring and responding to changes in these parameters, the system maintains optimal performance across different operating conditions while keeping the control interface simple through automated ECU management.
2Reliability
If exhaust gas temperature is used for engine corrections, then overheating prevention is improved, but control precision deteriorates when using constant correction over wide temperature ranges
Solution Approach 1:
The patent segments the temperature control approach by applying different correction strategies for different temperature ranges. Rather than using a single constant correction, the system divides the operating range and applies appropriate corrections for each segment, improving precision while maintaining reliable overheating prevention across the full temperature spectrum.
Solution Approach 2:
The system transitions from static constant correction to dynamic temperature-based correction. The ECU continuously adjusts fuel and ignition parameters based on real-time exhaust gas temperature readings, allowing the correction amount to vary dynamically with temperature conditions, thereby achieving both reliable overheating prevention and precise temperature control.
3Device complexity
If throttle valve position alone controls engine operations, then device complexity is reduced, but engine efficiency deteriorates due to inability to compensate for pressure and temperature variations
Solution Approach 1:
The ECU serves multiple functions: it monitors throttle position, inlet pressure, exhaust gas temperature, and engine speed, then integrates this information to control fuel injection, ignition timing, and air-fuel ratio. This multi-functional approach improves engine efficiency through comprehensive parameter monitoring while keeping the overall device complexity manageable by consolidating control functions in a single microprocessor-based unit.
Data Source
AI summary
Embodiments describe a method of controlling a two-stroke internal combustion engine. A method of controlling a two-stroke internal combustion engine includes determining a base nominal exhaust gas temperature, determining a base barometric pressure correction to base nominal exhaust gas temperature, determining exhaust gas temperature differential, determining exhaust gas temperature injection correction, and utilizing the exhaust gas temperature injection correction to make a final short-term fuel or ignition correction.