Compression Release Engine Brake Reset Piston Mechanism
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Solution Overview
Problem
Compression release type engine brakes face issues with premature contact between the exhaust valve and engine piston due to delayed exhaustion of brake oil, leading to increased wear and limited reset valve lift caused by a fixed reset bracket position.
Innovation Solution
A compression release type engine brake design that includes a reset piston and solenoid valve system to automatically exhaust engine brake oil and initialize pressure within the brake module, preventing piston contact and enhancing reset valve lift through a movable reset piston and predetermined oil supply angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the brake module retains brake oil pressure to maintain exhaust valve opening, then braking force is sustained, but the exhaust valve opens further causing contact with the engine piston
Solution Approach 1:
The reset piston functions as a feedback mechanism that automatically detects and responds to excessive valve lift. When the valve bridge reaches a predetermined position indicating sufficient valve opening, the reset piston is actuated to trigger the reset valve, which then exhausts the brake oil pressure. This closed-loop feedback system prevents over-opening while maintaining reliable braking force during normal operation.
Solution Approach 2:
The system performs self-regulation through the automatic reset mechanism. The reset piston and reset valve work autonomously to exhaust brake oil pressure when the valve bridge reaches the predetermined position, eliminating the need for external control systems. This self-service feature ensures the exhaust valve opens sufficiently for braking while automatically preventing excessive opening that would cause piston contact.
2Reliability
If a reset bracket is added to exhaust brake oil and initialize pressure, then valve contact is prevented, but the device size increases
Solution Approach 1:
The reset piston is integrated directly into the existing brake module structure, merging the reset function with the brake actuation mechanism. The reset piston utilizes the same space and structural framework as the brake piston, eliminating the need for a separate reset bracket assembly. This integration maintains valve contact prevention capability while avoiding the size increase that would result from adding a separate reset bracket.
3Device complexity
If the reset bracket position is fixed, then the structure is simplified, but the reset valve lift is limited
Solution Approach 1:
The reset piston transforms the static reset bracket position into a dynamic reset mechanism. The reset piston moves in response to brake oil pressure changes and valve bridge position, dynamically adjusting the reset valve lift. This dynamic operation allows the reset valve to achieve sufficient lift for complete brake oil exhaustion without requiring a fixed bracket positioned at an optimally complex location.
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
Prevents contact between the exhaust valve and engine piston, ensuring reduced wear and increased braking performance by automatically exhausting brake oil and providing sufficient lift to the reset valve, regardless of rocker arm rotation radius.
Implementation Method 1
when the reset oil is supplied, the reset piston moves downward by the reset oil pressure
Implementation Method 2
the brake piston moves downward to remove the gap between the exhaust rocker arm and the exhaust cam
Data Source
AI summary
A compression release type engine brake includes an exhaust rocker arm including a roller which is mounted at one end portion thereof, and the exhaust rocker arm rotating around a rocker arm shaft by the rotation of the exhaust cam, a valve bridge disposed on the other end portion of the exhaust rocker arm and connected to an exhaust valve, a brake module mounted between the exhaust rocker arm and the valve bridge, contacting with the roller and the brake cam lobe according to inflow of selectively supplied operation oil to open the exhaust valve by the exhaust cam, and the brake module including a reset valve closing operation oil inside therein, and a reset piston slidably mounted on the second end portion of the exhaust rocker arm and protruding out of the second end portion of the exhaust rocker arm according to the supply of reset oil to push the reset valve to expel the operation oil in the brake module outwards.