Side-Mounted Ignition Assembly for Piston Engine Combustion Control
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Solution Overview
Problem
Conventional piston engines with moving pistons face challenges in installing ignition plugs, cylinder pressure sensing, and valve configurations due to the absence of a fixed cylinder head, necessitating innovative solutions for practical manufacturing and cost-effectiveness.
Innovation Solution
The implementation of a piston engine design featuring a main piston and an auxiliary piston moving at different frequencies and stroke distances, with an ignition assembly and pressure sensor passage that adjusts fuel injection and ignition timing to maintain peak combustion pressure beyond 30° crank angle, ensuring higher fuel efficiency and reduced cylinder pressure stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a fixed cylinder head is replaced by a moving piston to create an extended minimum combustion volume, then the combustion chamber volume trajectory is widened and peak combustion can be located at bigger crank angle to boost output torque, but there is no space on the top side of the cylinder to install ignition plug, intake and exhaust valves
Solution Approach 1:
The ignition assembly is relocated from the traditional top-side mounting position to a side-mounted position on the cylinder wall. This dimensional relocation allows the ignition plug to access the combustion chamber through a cut-out passage in the cylinder liner, eliminating the need for space on the cylinder head top surface while maintaining proper ignition function.
Solution Approach 2:
The ignition assembly is extracted from the conventional cylinder head mounting location and repositioned on the cylinder wall. This extraction removes the spatial conflict between the ignition plug installation and the moving piston configuration, allowing independent optimization of both the combustion chamber geometry and the ignition system placement.
2Use of energy by moving object
If the combustion chamber volume is extended to maintain constant volume from 0° CA to 30° CA, then fuel efficiency is improved by maintaining peak pressure beyond 30° CA, but the device complexity increases due to the need for coordinated piston movements and additional passages
Solution Approach 1:
The auxiliary piston serves multiple functions: it defines the combustion chamber volume trajectory, provides a sealing surface for the ignition assembly, and acts as a movable barrier that controls the cut-out passage. This multi-functionality reduces the need for separate components and simplifies the overall system despite the coordinated movement requirements.
Solution Approach 2:
The cut-out passage in the cylinder liner acts as an intermediary connection between the ignition assembly and the combustion chamber. This passage is strategically positioned to remain open during the combustion stroke, allowing ignition and pressure sensing functions to operate effectively while maintaining the extended volume geometry.
3Reliability
If the auxiliary piston blocks the cut-out passage during certain strokes, then the combustion chamber is sealed properly, but the ignition assembly must use an alternative by-pass passage which adds structural complexity
Solution Approach 1:
The passage configuration is designed to be dynamic rather than static. The cut-out passage is positioned and dimensioned to automatically open and close based on the auxiliary piston's position. During the combustion stroke, the passage remains open to allow ignition and pressure sensing, while during other strokes it closes to seal the combustion chamber. This dynamic behavior eliminates the need for additional control mechanisms.
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 configuration enhances fuel efficiency and reduces cylinder temperature stress by maintaining a nearly constant combustion chamber volume, allowing for flexible fuel injection and combustion control, thereby improving torque output and engine performance.
Implementation Method 1
a pressure sensor passage within the ignition assembly is configured to make available to detect the combustion chamber pressure or cylinder pressure in combustion stroke
Implementation Method 2
an ignition assembly is mounted sealingly on the cylinder wall, the ignition assembly connects to the combustion chamber via a cut-out passage
Data Source
AI summary
An ignition assembly configuration in piston engine with a main piston and an auxiliary piston, the ignition assembly is mounted on the cylinder wall and connects to the combustion chamber; the ignition assembly comprises an connection cut-out passage, an ignition device, or ignition device combined with a fuel injection nozzle, or an ignition device combined with a fuel injection nozzle and a pressure sensor passage. Wherein the auxiliary piston has a by-pass passage to keep the ignition assembly connected to the combustion chamber when the auxiliary piston moves down below the uppermost position of the main piston and blocks the ignition assembly cut-out passage; wherein the uppermost position of the ignition assembly is at or aligned with the uppermost position of the auxiliary piston in combustion stroke, the lowermost position of the ignition assembly is at or aligned with the uppermost position of the main piston. Fuel-water injection, multiple fuel injections and combustions can be easily practiced in the new configuration.