Engine Variable Valve Mechanism Gap Compensation

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Solution Overview

Problem

Conventional engine variable valve driving mechanisms face issues with incomplete valve closing due to conflicts between hydraulic gap adjustment devices and servo piston mechanisms, and solenoid valves fail to prevent high-pressure oil backflow, leading to oil pressure fluctuations between cylinders.

Innovation Solution

An engine variable valve driving mechanism featuring a rocker arm with a servo rocker arm arranged in parallel, a gap compensating device that telescopically adjusts the valve adjustment gap, and a plunger ejection structure to delay or advance valve opening and closing, ensuring complete valve closure and preventing oil backflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple control oil passages are used in the solenoid valve, then the valve can be controlled to open and close, but the valve cannot close completely due to conflict with the hydraulic gap adjustment device

Engineering Contradiction:

Improvevalve controlVSAvoidvalve closing completeness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent extracts the gap adjustment function from the traditional hydraulic gap adjustment device and implements it through the telescopic extension of the servo rocker arm. This separation removes the conflict between the gap adjustment mechanism and the valve closing mechanism, allowing the valve to close completely while maintaining adjustable gap control.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The servo rocker arm acts as an intermediary between the cam follower and the rocker arm. By introducing this intermediate component with telescopic capability, the system can adjust the gap without interfering with the valve closing action, resolving the conflict between gap control and complete valve closure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If the solenoid valve prevents high-pressure oil from flowing back, then lift loss is prevented, but oil pressure fluctuations between cylinders cannot be eliminated

Engineering Contradiction:

Improvelift lossVSAvoidoil pressure stability

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent segments the oil control system by providing separate oil filling passages for the servo rocker arm and the rocker arm. This segmentation allows independent pressure control, preventing pressure fluctuations from propagating between cylinders while still preventing high-pressure oil backflow that causes lift loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements local quality control by providing different oil filling passages with different pressure characteristics for different components. The servo rocker arm receives oil at one pressure level while the rocker arm receives oil at another pressure level, allowing local optimization of both lift loss prevention and pressure stability.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If a hydraulic gap adjustment device is used, then the gap can be adjusted, but it conflicts with the servo piston mechanism causing incomplete valve closing

Engineering Contradiction:

Improvegap adjustmentVSAvoidvalve closing completeness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the gap adjustment function from the hydraulic gap adjustment device and relocates it to the servo rocker arm through telescopic extension. This extraction eliminates the conflict with the servo piston mechanism while preserving the adaptability of gap adjustment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the hydraulic gap adjustment device with a mechanical telescopic extension mechanism in the servo rocker arm. This substitution eliminates the hydraulic conflict while maintaining gap adjustability through a purely mechanical means.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The solution effectively addresses incomplete valve closing and oil pressure fluctuations by allowing the gap compensating device to adjust the valve adjustment gap, ensuring late closing or early opening of the valve, thereby improving engine performance and stability.

Implementation Method 1

a plunger ejection structure arranged at the swing end of the rocker arm for abutting and cooperating with the press block

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentUS11486273B2Variable valve driving mechanism of engine, and engine

Publication Date: 2022.11.01 WEICHAI POWER CO LTD

AI summary

A variable valve driving mechanism of an engine includes a rocker arm configured to control open and close of a valve and a servo rocker arm arranged in parallel to the rocker arm. A swing end of the servo rocker arm extends to the top of the swing end of the rocker arm. A valve adjustment gap provided in the swing direction of the servo rocker arm and the rocker arm is formed between the servo rocker arm and the rocker arm. A gap compensating device telescopically filling the valve adjustment gap and configured to adjust the valve to be delayed to close or open in advance when extending to the valve adjustment gap is provided between the servo rocker arm and the rocker arm.