Valve Timing Control Inversion for Engine Startability
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Solution Overview
Problem
Existing valve opening and closing timing control apparatuses for internal combustion engines fail to ensure startability, especially when the electric valve timing control system malfunctions, particularly at low temperatures, due to the intake valve being displaced to a most retarded angle phase, which inhibits compression ratio and ignition performance.
Innovation Solution
The apparatus changes the phase of the electric-type valve opening and closing timing control to the most advanced angle phase for both intake and exhaust valves upon malfunction, using a control unit that adjusts the idle speed and ignition timing based on sensor data to enhance startability and compatibility with various engine types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric valve opening and closing timing control apparatus is controlled to a most retarded angle phase upon failure, then the internal combustion engine can start in conventional engine types, but the engine cannot restart in Atkinson cycle engines due to insufficient compression ratio and cylinder temperature
Solution Approach 1:
The patent inverts the conventional failure response by controlling the electric valve timing apparatus to a most advanced angle phase instead of a most retarded angle phase upon malfunction. This inversion resolves the contradiction because the advanced phase ensures sufficient compression ratio and cylinder temperature for both conventional engines and Atkinson cycle engines, making the system universally applicable while maintaining startability.
2Device complexity
If the intake valve is displaced to a most retarded angle phase upon failure, then the valve timing control is simplified, but the actual compression ratio is not secured at low temperatures leading to decreased ignition performance
Solution Approach 1:
The patent applies inversion by displacing the intake valve to a most advanced angle phase upon failure instead of a retarded phase. This ensures that the compression ratio is maintained and ignition performance is preserved, particularly at low temperatures, while still providing a deterministic and simple control strategy.
3Ease of manufacture
If the electric valve timing control apparatus is designed for conventional engines with retarded angle failure position, then it works for those engines, but it cannot be applied to Atkinson cycle engines which require advanced angle positioning for proper operation
Solution Approach 1:
The patent achieves universality by designing the failure mode to control the valve timing apparatus to a most advanced angle phase, which is beneficial for both conventional engines and Atkinson cycle engines. This single design specification enables the system to function properly across different engine types, eliminating the need for type-specific failure mode designs.
Data Source
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AI summary
To provide a valve opening and closing timing control apparatus which is applicable to various types of internal combustion engines and which includes improved startability. The valve opening and closing timing control apparatus includes a valve opening and closing timing control apparatus provided at a camshaft for an intake valve opening and closing the intake valve of an internal combustion engine and a valve opening and closing timing control apparatus provided at a camshaft for an exhaust valve opening and closing the exhaust valve, at least one of the valve opening and closing timing control apparatus for the intake valve and the valve opening and closing timing control apparatus for the exhaust valve being an electric type and includes a control unit changing a phase of one of the valve opening and closing timing control apparatus for the intake valve and the valve opening and closing timing control apparatus for the exhaust valve serving as the electric type which malfunctions to a most advanced angle phase and changing a phase of the other of the valve opening and closing timing control apparatus for the intake valve and the valve opening and closing timing control apparatus for the exhaust valve which is inhibited from malfunctioning to an advanced angle side to decrease an overlap amount between the intake valve and the exhaust valve in a case where one of the valve opening and closing timing control apparatus for the intake valve and the valve opening and closing timing control apparatus for the exhaust valve serving as the electric type malfunctions.