Valve Lash Adjustment via Cranking Gas Pressure Profiling

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Solution Overview

Problem

Internal combustion engine valves experience wear and thermal expansion issues, leading to improper sealing and potential engine damage due to existing methods for adjusting valve lash and monitoring wear, which often require active combustion cycles and may result in loss of efficiency or engine damage.

Innovation Solution

A method and valve assembly that adjust valve lash and monitor wear by rotating the engine with a starter, measuring gas pressure parameters, determining a parameter profile, and adjusting the valve lash or monitoring wear based on this profile before the combustion cycle starts, using a sensor device and control unit to analyze the engine's pressure behavior during non-combustion cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If valve lash adjustment and wear monitoring are performed during active combustion cycles, then measurement data can be obtained, but engine damage or loss of efficiency occurs

Engineering Contradiction:
Improvevalve lash measurementVSAvoidengine safety
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing valve lash measurement and wear monitoring during engine cranking before the combustion cycle begins. The measurement system captures pressure profiles during the cranking phase, allowing valve condition assessment to be completed before combustion starts, thus avoiding engine damage while obtaining necessary measurement data.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If valve lash is too large, then sealing is improved, but power loss and noise increase

Engineering Contradiction:
Improvevalve sealingVSAvoidengine power
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent applies feedback by using pressure profile measurements taken during engine cranking to determine the actual valve lash condition. This feedback information is then used to adjust the valve lash to optimal values that balance sealing reliability with power output, preventing both excessive clearance and overly tight adjustment.

Inventive Principle:
Principle #23Feedback

3Power

If valve lash is too small, then power loss is reduced, but valve may not close completely causing burning

Engineering Contradiction:
Improveengine powerVSAvoidvalve sealing
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies preliminary action by measuring valve lash conditions during cranking before combustion occurs. This allows the valve lash to be adjusted to the minimum safe value that ensures complete valve closure, maximizing power output while preventing valve burning by identifying the optimal setting before the engine operates under thermal stress.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4491862A1Method for adjusting a valve lash and monitoring wear of a valve during engine start and valve assembly
Publication Date: 2025.01.15 CATERPILLAR ENERGY SOLUTIONS
  • EP4491862A1 patent drawingFigure 1
  • EP4491862A1 patent drawingFigure 2
  • EP4491862A1 patent drawing

AI summary

The present invention pertains to a method (1) for adjusting a valve lash (234) and/or monitoring wear of a valve in an internal combustion engine. The method (1) comprises the steps of rotating (S1) the engine by an engine starter (4), measuring (S2) a parameter indicative of a gas pressure in the engine while rotating the engine, determining (S3) a corresponding parameter profile based on the measured parameter indicative of the gas pressure in the engine and adjusting (S4) the valve lash and/or monitoring wear of the valve (23) based on the determined parameter profile. Furthermore, a valve assembly (2) suitable for carrying out the method according to the present disclosure may be provided, comprising at least one sensor device (5) and a control unit (3) communicatively coupled to the at least one sensor device (5).