Inlet Pipe Pressure Detection for Combustion Instability
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Solution Overview
Problem
Saddle riding type vehicles, such as two-wheeled motor vehicles, face challenges in accurately detecting combustion instability, which affects exhaust gas purification performance and fuel efficiency, as existing methods are not sufficiently precise in identifying misfires and variations in engine rotating speeds.
Innovation Solution
The implementation of an inlet pipe pressure detector and a determiner system that measures variations in inlet pipe pressure downstream of the air throttle valve, allowing for high-accuracy detection of combustion instability by sensing changes in pressure that indicate instability, and a controller that adjusts air intake and ignition timing to stabilize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If engine rotating speed detection methods are used to detect combustion instability, then misfire can be detected, but the detection accuracy is insufficient and cannot reliably identify combustion instability in early stages
Solution Approach 1:
The patent introduces inlet pipe pressure as an intermediary parameter to detect combustion instability. Instead of directly measuring combustion characteristics or relying on engine rotating speed variations, the system uses pressure fluctuations in the inlet pipe as a mediator that reflects combustion state changes, enabling more accurate and reliable detection of instability in its early stages.
Solution Approach 2:
The patent replaces the mechanical detection method (engine rotating speed measurement) with a pressure-based detection method. By substituting the mechanical inertia-based detection with pressure field measurement, the system achieves higher sensitivity and accuracy in detecting combustion instability before it manifests as significant rotating speed variations.
2Temperature
If air intake volume is increased and ignition timing is retarded to activate catalyst early, then catalyst activation is accelerated, but combustion stability deteriorates
Solution Approach 1:
The patent implements a feedback control mechanism where inlet pipe pressure is continuously monitored and used to adjust air intake and ignition timing. When combustion instability is detected through pressure fluctuations, the system automatically adjusts operating parameters to restore stability, enabling the catalyst activation strategy to proceed while maintaining combustion stability through real-time corrections.
3Loss of time
If existing misfire detection systems are used, then combustion instability can be detected after it occurs, but early detection and prevention capability is limited
Solution Approach 1:
The patent enables preliminary detection of combustion instability by monitoring inlet pipe pressure fluctuations that occur before significant engine performance degradation or misfire events. This allows the system to take preventive action earlier in the combustion instability development process, reducing time loss and improving detection precision by identifying issues at their inception rather than after they manifest as rotating speed variations.
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 solution enables precise detection and stabilization of combustion instability, improving exhaust gas purification performance and fuel efficiency by accurately identifying and responding to changes in inlet pipe pressure, thereby enhancing the vehicle's environmental measures.
Implementation Method 1
an inlet pipe pressure detector for detecting, as inlet pipe pressure, a manifold air pressure in the inlet pipe downstream of the air throttle valve
Data Source
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AI summary
A saddle riding type vehicle driven by a straddling rider includes an engine having a combustion chamber, an inlet pipe for introducing a fuel-air mixture into the combustion chamber, an air throttle valve attached to the inlet pipe for adjusting quantity of the fuel-air mixture supplied to the combustion chamber, an inlet pipe pressure detector for detecting, as inlet pipe pressure, a manifold air pressure in the inlet pipe downstream of the air throttle valve, and a determiner for determining that combustion in the engine has become unstable based on variations in the inlet pipe pressure.