Engine Decompression Device With Cylinder-Specific Arm Directions
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Solution Overview
Problem
Existing decompression devices in engines can malfunction due to rotational fluctuations, leading to compression loss and abnormal noise, particularly in multi-cylinder engines with unequal combustion intervals.
Innovation Solution
A decompression device with adjustable opening directions for each cylinder, where the opening direction of the decompression arm can be set in the same or opposite direction to the rotation direction of the exhaust camshaft, using a decompression cam, arm, and spring configuration to stabilize decompression and prevent malfunction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the decompression arm opening direction is set in the same direction as the camshaft rotation direction, then the decompression is not easily released when the engine is started, but the decompression may malfunction during operation when rotational fluctuation increases toward acceleration
Solution Approach 1:
The patent applies local quality by configuring different decompression arm opening directions for different cylinders based on their specific operational characteristics. Cylinders prone to rotational fluctuation during acceleration are configured with opposite opening directions to prevent malfunction, while other cylinders maintain the conventional same-direction configuration for reliable starting performance.
2Reliability
If the decompression arm weight or spring load is adjusted to prevent malfunction during rotational fluctuation, then the decompression stability improves, but the design complexity and working hours increase
Solution Approach 1:
The patent employs asymmetry by configuring the decompression arm opening directions asymmetrically relative to the camshaft rotation direction for specific cylinders. Instead of uniformly adjusting weights or spring loads across all cylinders, the invention creates asymmetric configurations tailored to individual cylinder requirements, thereby achieving stability without increasing overall design complexity.
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 compression loss and abnormal noise by stabilizing decompression operations, without the need for weight or load adjustments of the decompression arm or spring, thus reducing design changes and working hours.
Implementation Method 1
a decompression arm that moves in an opening direction due to centrifugal force accompanying rotation of the exhaust camshaft to protrude the decompression cam
Implementation Method 2
a spring that moves the decompression arm in a closing direction by spring force resisting the centrifugal force to immerse the decompression cam
Data Source
AI summary
A decompression device is attached to an exhaust camshaft, and the exhaust camshaft is supported by a cylinder head. The decompression device includes a decompression camshaft formed with a decompression cam that can protrude and be immersed with respect to a base circle of an exhaust cam of the exhaust camshaft, a decompression arm that moves in an opening direction due to centrifugal force accompanying rotation of the exhaust camshaft to protrude the decompression cam, and a spring that moves the decompression arm in a closing direction by spring force resisting the centrifugal force to immerse the decompression cam. In the decompression device, the opening direction of the decompression arm can be changed in a same direction or in an opposite direction to a rotation direction of the exhaust camshaft for each cylinder.