Engine Valve Actuation With Integrated Mechanical Braking
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Solution Overview
Problem
Conventional engine braking systems increase the height, weight, and cost of engines due to their integration as additional accessories, and suffer from hydraulic compliance issues that affect valve lift and response time.
Innovation Solution
An engine valve actuating apparatus with a solid chain mechanism that integrates into the engine, reducing height and weight, eliminating hydraulic controls, and improving response time by using a link mechanism with a guide and anti-rotation mechanism to align and position the actuation piston.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hydraulic engine brake system is added to the engine, then engine braking function is achieved, but the engine height, weight, and cost increase
Solution Approach 1:
The patent merges the engine braking function with the existing valve actuating mechanism by integrating a braking piston into the valve actuating apparatus housing. This combination allows the braking system to share structural components with the valve train, eliminating the need for separate braking system components and reducing overall engine weight.
Solution Approach 2:
The valve actuating apparatus is designed to perform multiple functions: normal valve actuation via the cam mechanism and engine braking via the braking piston. The housing and associated components serve both valve actuation and braking purposes, making the system multi-functional and reducing the need for additional dedicated braking components.
2Adaptability or versatility
If a hydraulic engine brake system is added to the engine, then engine braking function is achieved, but the engine height increases
Solution Approach 1:
The braking piston is nested within the existing valve actuating apparatus housing, utilizing the same structural space. The braking piston fits within the housing that already contains the cam and valve actuation components, effectively nesting the braking function within the existing valve train structure rather than adding external components.
3Reliability
If the diameter of the hydraulic piston is increased to reduce compliance, then hydraulic system compliance decreases, but the piston size, weight, and response time worsen
Solution Approach 1:
The patent changes the physical parameters of the braking piston by using a smaller diameter piston with a shorter stroke. This parameter change reduces the volume of hydraulic fluid required, thereby reducing compressibility effects and improving response time while maintaining sufficient braking force through optimized piston positioning and mechanical leverage.
4Reliability
If a mechanical engine braking apparatus is integrated into the rocker arm, then hydraulic compliance issues are overcome, but the apparatus complexity increases
Solution Approach 1:
The mechanical linkage components (links, rotational couplings) are merged with the existing valve actuating mechanism. The link mechanism integrates the braking piston motion with the cam-driven valve actuation, combining braking and valve control functions into a unified mechanical system rather than separate independent systems.
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 apparatus reduces engine height and weight, eliminates hydraulic loading issues, and enhances reaction time while maintaining consistent valve lift, independent of oil pressure and temperature.
Implementation Method 1
When engine oil is supplied to the activation piston bore through a fluid passage in the housing, the pressure of the engine oil moves the link mechanism
Implementation Method 2
The actuation piston includes at least one side surface that is in sliding contact with the inner cylindrical surface of the actuation piston bore so that the actuation piston can slide within the actuation piston bore
Data Source
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AI summary
An engine valve actuating apparatus (100) includes a housing (210), the housing (210) including an activation piston bore (260) and an actuation piston bore (190); an activation piston (162) disposed in the activation piston bore (260); an actuation piston (130) disposed in the actuation piston bore (190) to actuate the engine valve; wherein the actuation piston (130) includes at least one side surface (135) that is in sliding contact with the inner surface of the actuation piston bore (190) so that the actuation piston (130) can slide within the actuation piston bore (190); and a link mechanism (182) that includes a first link (184) and a second link (186); the actuation piston (130) including a guide mechanism (137), wherein the guide mechanism (137) guides the first and second links (184,186) to move in a plane between the first position and the second position, wherein at least a part of the guide mechanism (137) is below at least a part of the at least one side surface (135) of the actuation piston (130).