Internal Combustion Engine Valve Seat Rim Timing

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Solution Overview

Problem

Conventional two-stroke and four-stroke internal combustion engines face challenges in achieving effective gas exchange due to thermal loading, distortions, and limitations in valve train dynamics, leading to inefficiencies in fuel efficiency and gas exchange rates.

Innovation Solution

The design incorporates ports with valve seats and valve seat rims in the cylinder head, delaying the opening and advancing the closing of ports, which facilitates rapid and efficient gas exchange by increasing the effective flow area and optimizing valve lift durations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ports are provided in the cylinder wall for simultaneous intake and exhaust strokes in two-stroke engines, then the gas exchange rate is improved, but mixing of charge and combustion products occurs and charge leakage increases

Engineering Contradiction:

Improvegas exchange rateVSAvoidcharge containment

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent divides the gas exchange function into separate intake ports and exhaust ports located at different positions in the cylinder wall, allowing independent control of charge intake and exhaust product removal, thereby preventing mixing and leakage while maintaining high exchange rates

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intake ports are positioned and timed to open before the exhaust stroke completes, ensuring charge is ready for intake before exhaust products are fully expelled, optimizing the sequence to prevent mixing while maintaining continuous gas exchange

Inventive Principle:

Principle #10Preliminary action

2Reliability

If ports and valves are provided in the cylinder head for four-stroke engines, then charge containment is improved, but flow deficiency occurs due to conventional valve characteristics

Engineering Contradiction:

Improvecharge containmentVSAvoidflow quantity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the valve seat geometry by providing a valve seat rim that extends into the port, changing the flow characteristics and increasing the effective flow area during valve opening, thereby improving flow quantity while maintaining charge containment through proper valve sealing

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If valve seat rim is provided to delay opening and advance closing of ports, then fuel efficiency is improved through higher expansion ratio, but valve lift duration is reduced

Engineering Contradiction:

Improvefuel efficiencyVSAvoidvalve lift duration

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of moving object

Solution Approach 1:

The valve seat rim is designed with specific dimensions and positioning to optimize the delay in port opening and advance in port closing, achieving the desired expansion ratio improvement while maintaining adequate valve lift duration through careful parameter selection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The valve seat rim provides a controlled partial delay in opening and advance in closing, sufficient to improve expansion ratio and fuel efficiency without excessively reducing valve lift duration, balancing the trade-off through moderate application of the principle

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP2683920B1Internal combustion engine

Publication Date: 2020.05.06 TVS MOTOR CO LTD

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AI summary

The subject matter described herein relates to an internal combustion engine (100). The internal combustion engine (100) comprises at least one port (132, 134), and a valve (164, 166) provided at the port (132, 134) to regulate opening and closing of the port (132, 134). A valve seat (202, 302) is also provided at the port (132, 134) for resting the valve (164, 166). Further, a valve seat rim (204, 304) is provided at the valve seat (202, 302) to delay opening and to advance closing of the port (132, 134).