Valve Actuation System with Rotational Coupling
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Solution Overview
Problem
Existing valve actuation systems for internal combustion engines are not fully satisfactory in terms of compactness, sustainability, and mechanical efficiency, particularly in heavy-duty and medium-duty vehicles.
Innovation Solution
A valve actuation system with a rocker and lever mechanism that includes a rotational coupling with a transmission ratio greater than 1, allowing for a limited rotation of the lever to activate the reset valve, reducing mechanical forces and improving packaging and robustness, while also enhancing mechanical efficiency and reducing inertia and imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a direct coupling between the lever and reset valve is used, then the reset valve can be activated, but the mechanical forces and inertia are high, reducing mechanical efficiency and robustness
Solution Approach 1:
A rotational coupling mechanism is introduced as an intermediary between the lever and reset valve. This coupling includes a transmission ratio greater than 1, which acts as a mechanical mediator to reduce the forces transmitted from the lever to the reset valve, thereby improving reliability while reducing mechanical stress
Solution Approach 2:
The transmission ratio of the rotational coupling is designed to be greater than 1, changing the mechanical parameter of force transmission. This parameter change allows the system to reduce mechanical forces and inertia while maintaining the ability to activate the reset valve effectively
2Reliability
If a complex valve actuation system is used to achieve engine brake function, then the valve can be opened, but the system is not compact and mechanical efficiency is reduced
Solution Approach 1:
The lever and reset valve are integrated into a single rotational coupling mechanism. The lever's rotation directly couples to the reset valve's activation through the rotational coupling, merging two previously separate functions into one compact assembly, thereby achieving engine brake function without increasing system complexity
Solution Approach 2:
The rotational coupling mechanism serves multiple functions: it transmits motion from the lever to the reset valve, reduces mechanical forces through its transmission ratio, and enables compact packaging. This multi-functionality allows the system to achieve engine brake function while maintaining compactness and mechanical efficiency
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 system achieves improved mechanical efficiency, reduced mechanical forces, and increased robustness with a longer service life, allowing for more compact designs and enhanced reliability in valve actuation systems.
Implementation Method 1
a camshaft with a cam for each rocker, said cam cooperating with a cam follower at one end of the rocker
Implementation Method 2
a hydraulic circuit with valve means for supplying or draining a fluid to and from said chamber
Implementation Method 3
a reset valve which, in an active position, causes the fluid to be drained out of the chamber
Implementation Method 4
rotational coupling means between the lever and the reset valve, said rotational coupling means having a transmission ratio greater than 1
Data Source
AI summary
A valve actuation system for an internal combustion engine The valve actuation system (S) for an internal combustion engine comprises: ⋅a rocker (6) pivotably mounted around a pivot axis (A6), comprising: ⋅a driven end portion (62) for cooperating with a rotating cam including a main bump and at least one smaller auxiliary bump; ⋅an actuating end portion (63) including a piston (8) for opening at least one valve of the engine following the cooperation of the driven end portion (62) with a bump of the cam, the piston (8) being slidably mounted relative to the rocker (6) between a extended position allowing said piston (8) to open said valve when the driven end portion (62) contacts the auxiliary bump, and a retracted position preventing said piston (8) to open said valve when the driven end portion (62) contacts the auxiliary bump; ⋅a fluid circuit for causing the piston (8) to move from its retracted position to its extended position; ⋅a reset circuit comprising a reset valve (99) rotatably mounted relative to the rocker (6), between an inactive position, and an active position in which the reset valve (99) causes the fluid to be drained out of the fluid circuit to allow the piston (8) to move towards its retracted position; ⋅a lever (7) pivotably mounted around a pivot axis (A6), the lever (7) having a driven end portion (72) adapted to cooperate with a rotating reset cam including a bump, and an actuating end portion (73) for rotating the reset valve (99) from its inactive position towards its active position following the cooperation of the lever driven end portion (72) with the bump of the reset cam; ⋅rotational coupling means (75, 95) between the lever (7) and the reset valve (99), said rotational coupling means having a transmission ratio greater than 1.