Modular Valve Unit Pre-Adjustment for Engine Assembly
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Solution Overview
Problem
The assembly of variable valve units in internal combustion engines is time-consuming and inefficient due to the need for precise adjustments and sensor installation, causing stagnation on the main assembly line, especially when trying to achieve uniform valve characteristics across cylinders.
Innovation Solution
A modular valve unit design that includes a camshaft, a variable valve operating mechanism, and a sensor, where the sensor is exposed outside the rocker cover, allowing for cylinder-to-cylinder variation adjustment before assembly, and using an adjustment mechanism to fine-tune valve drive output for each cylinder, with retaining members to secure the components to the cylinder head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable valve unit is modularized on sub-line, then assembly time on main line is reduced, but adjustment work for eliminating cylinder variation still causes stagnation on main line
Solution Approach 1:
The patent applies preliminary action by performing all adjustment work for eliminating cylinder variation on the sub-line before the modularized variable valve unit is returned to the main line. The adjustment mechanism allows cylinder-to-cylinder variation to be eliminated in advance, so that when the unit is assembled on the main line, no further adjustment is needed, thus resolving the contradiction between reduced assembly time and adjustment time causation of stagnation.
2Device complexity
If sensor is attached inside rocker cover, then assembly is compact, but sensor maintenance requires engine disassembly
Solution Approach 1:
The patent applies the taking out principle by extracting the sensor from the enclosed space inside the rocker cover and positioning it on the external surface of the cylinder head. This allows the sensor to be easily accessible for maintenance without requiring engine disassembly, while still maintaining a compact overall assembly design through proper spatial arrangement.
3Ease of operation
If fine adjustment mechanism is incorporated in variable valve unit, then adjustment work is facilitated, but adjustment must be performed after attachment to cylinder head
Solution Approach 1:
The patent applies preliminary action by enabling all necessary adjustment operations to be performed on the modularized variable valve unit on the sub-line before it is attached to the cylinder head on the main line. The adjustment mechanism is designed to allow complete adjustment of valve drive output for each cylinder in advance, eliminating the need for post-attachment adjustment and thus preserving main line assembly efficiency.
Data Source
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AI summary
A valve unit of an internal combustion engine is accommodated in a space between a cylinder head (1) and a rocker cover (3). The valve unit comprises a camshaft (15), a variable valve operating mechanism (13, 200), a sensor (16), and a retaining member (11a, 11b, 11c). The camshaft (15) is provided with a cam (38a, 38b) for each cylinder (6). The variable valve operating mechanism (13, 200) receives a displacement of the cam (38a, 38b), outputs a valve drive output, and continuously variable-controls the valve drive output in accordance with a rotational displacement of a control shaft (14) provided substantially in parallel with the camshaft (15). The sensor (16) detects the rotational displacement of the control shaft (14). The retaining member (11a, 11b, 11c) retains the camshaft (15), the variable valve operating mechanism (13, 200), and the sensor (16). The retaining member (11a, 11b, 11c) expose the sensor (16) to the out side of the rocker cover (3) thereby to fix the camshaft (15), the variable valve operating mechanism (13, 200), and the sensor (16) to the cylinder head (1).