Prechamber Valve Actuation via Shared Rocker Arm
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Solution Overview
Problem
The complexity and limited control of prechamber valve operation in lean burn piston engines, particularly due to the need for a separate cam and mechanism, hinder efficient combustion efficiency and nitrogen oxide reduction.
Innovation Solution
A prechamber arrangement with a spring-loaded valve and a dual-chamber system, actuated by the same mechanism as the inlet valve, allowing adjustable lift and timing through varying piston surface areas, eliminating the need for a separate cam and mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate cam and mechanism are used for prechamber valve operation, then the prechamber valve can be controlled independently, but the device complexity increases
Solution Approach 1:
The patent combines the prechamber valve actuation mechanism with the main inlet valve actuation mechanism. The rocker arm that actuates the inlet valve is extended or modified to also actuate the prechamber valve, eliminating the need for a separate cam and pushrod mechanism. This merging of functions reduces device complexity while maintaining independent control capability through shared actuation timing.
Solution Approach 2:
The rocker arm is designed to serve dual functions: actuating both the main inlet valve and the prechamber valve. By making the actuation mechanism universal, the patent eliminates redundant components (separate cam, pushrod, rocker arm for prechamber valve) while preserving the ability to independently control valve timing through appropriate design of the actuation linkage.
2Volume of moving object
If a spring-loaded prechamber valve with short lift is used, then the valve structure is compact, but the control precision is hampered
Solution Approach 1:
The patent employs a dynamic control mechanism where the prechamber valve lift is not fixed but can be varied through the actuation system. The rocker arm mechanism with adjustable geometry or additional linkage allows the valve lift to be dynamically controlled despite the compact size, enabling precise control of valve opening duration and timing without requiring a long fixed lift.
Solution Approach 2:
The patent changes the control parameters of the prechamber valve by adjusting the actuation timing, duration, and lift magnitude through the modified rocker arm mechanism. This allows precise control of the valve operation parameters (when it opens, how long it stays open, and how far it opens) while maintaining a compact valve structure with relatively short physical lift distance.
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
Simplifies the prechamber valve operation, allowing for improved control over combustion efficiency and reduced nitrogen oxide formation by optimizing the prechamber valve lift and timing, enhancing combustion completeness.
Implementation Method 1
The chamber (28) is delimited by the piston surface (32) of the prechamber valve (19) on which piston surface the pressure of the pressure medium acts to move the prechamber valve (19) toward the open position
Implementation Method 2
A spring-loaded prechamber valve (19) provided with a piston surface (32) for feeding a mixture of combustion air and fuel into the prechamber (17), and ignition means for igniting mixture of combustion air and fuel in the prechamber. The prechamber valve can be moved between an open and closed position and is pressed toward the closed position by a spring
Implementation Method 3
When a mixture of fuel and air is combusted in combustion engines, nitrogen oxides (NOx) are formed
Data Source
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AI summary
A prechamber arrangement adaptable in the upper part (2) of a cylinder in a piston engine (1), the prechamber arrangement comprising a prechamber (17), a spring-loaded prechamber valve (19) provided with a piston surface (32) for feeding a mixture of combustion air and fuel into the prechamber (17), and ignition means (20) for igniting the mixture of combustion air and fuel in the prechamber (17), which prechamber valve (19) can be moved between an open and closed position and which is pressed toward the closed position by a spring (24). The prechamber arrangement (15) comprises a chamber (28) for pressure medium and a second chamber (27) for pressure medium in flow connection with the chamber (28), which is delimited by the piston surface (32) of the prechamber valve on which the pressure of the pressure medium acts to move the prechamber valve (19) toward the open position, and which second chamber (27) is delimited by the piston surface (31) of a movable second piston (29).