Two-Stroke Opposed-Piston Engine Compression Release Valve
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Solution Overview
Problem
Conventional two-stroke opposed-piston engines lack a viable compression release braking function due to the inability to open exhaust valves at the top of the compression stroke, resulting in energy loss and inefficient braking performance.
Innovation Solution
A two-stroke opposed-piston engine design featuring a cylinder with an inlet piston and an exhaust piston, a combustion chamber, a charge air channel, and a conduit directly connecting the combustion chamber to the charge air channel, with a valve that selectively opens and closes flow communication through the conduit to implement a compression release brake function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional exhaust valve opening mechanism is used at the top of the compression stroke, then compression release braking function is achieved, but the opposed piston engine design prevents valve opening due to the exhaust piston blocking the exhaust port
Solution Approach 1:
Instead of opening the exhaust port from the exhaust side (conventional approach), the invention opens the exhaust port from the combustion chamber side using a valve (45) that releases compressed air directly into the charge air channel (31). This inverted approach bypasses the blocking exhaust piston and enables compression release braking in opposed piston engines
Solution Approach 2:
The invention introduces a conduit (43) as an intermediary pathway connecting the combustion chamber to the charge air channel, allowing compressed air to be redirected away from the exhaust system. This intermediary pathway enables the braking function without requiring direct exhaust port opening
2Power
If compressed air is released into the exhaust system, then braking function is achieved, but noise and heat dissipation issues arise
Solution Approach 1:
The invention extracts the compressed air release function from the exhaust system and relocates it to the charge air channel. By taking out the release pathway from the noisy exhaust system and placing it in the cooler charge air channel, the invention achieves braking power while minimizing noise and heat dissipation harmful factors
3Reliability
If the exhaust piston blocks the exhaust port, then the opposed piston engine structure is maintained, but compression release braking becomes impossible
Solution Approach 1:
The invention segments the exhaust release function into two separate pathways: the exhaust piston continues to control the exhaust port for normal exhaust function, while a separate valve (45) controls the conduit (43) for compression release braking. This segmentation allows both the opposed piston structure and braking function to coexist
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
Enables effective compression release braking by controlling the flow communication through the conduit, reducing energy loss and enhancing braking performance without directly releasing compressed air into the exhaust system, thus maintaining energy efficiency and minimizing noise and heat dissipation issues.
Implementation Method 1
a compression release braking function or engine retarder brake can be achieved by opening the exhaust valves at the top of the compression stroke, resulting in adiabatic expansion of the compressed air
Data Source
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AI summary
A two-stroke, opposed-piston engine includes a cylinder with an inlet piston controlled inlet port and an exhaust piston controlled exhaust port, the cylinder defining a combustion chamber with the inlet piston and the exhaust piston, a charge air channel in flow communication with the inlet port, a conduit extending directly from the combustion chamber to the charge air channel, and a valve arranged to selectively open and close flow communication through the conduit.