Variable Valve Actuation Controller for Engine Startability
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Solution Overview
Problem
In internal combustion engines with variable valve actuation devices, excessive hydraulic oil or pressure in the phase retarding chamber leads to increased resistance against valve timing advancement, causing prolonged engine start times and reduced startability.
Innovation Solution
A controller for the variable valve actuation device that adjusts the hydraulic oil supply to the phase advancing chamber based on residual oil amount or pressure, providing a greater force to advance the valve timing when residual oil is high, and locks the valve timing to a specific angular phase using a phase locking mechanism when residual oil is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a greater amount of hydraulic oil is supplied to the phase advancing chamber to overcome residual oil pressure, then the valve timing can be advanced more effectively, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The controller dynamically adjusts the amount of hydraulic oil supplied to the phase advancing chamber based on real-time detection of residual oil pressure. The system transitions from a static fixed-supply approach to a dynamic variable-supply approach, optimizing performance while managing complexity through intelligent control rather than mechanical complexity
Solution Approach 2:
The system employs feedback control by detecting residual oil pressure and using this information to adjust the hydraulic oil supply accordingly. This closed-loop approach allows the system to automatically adapt to varying conditions without requiring complex predetermined control mechanisms for each scenario
2Reliability
If the valve timing is locked to a specific angular phase using the phase locking mechanism, then the startability is improved, but the duration of action is reduced as the timing cannot be adjusted during operation
Solution Approach 1:
The system segments the valve timing control into two distinct phases: a starting phase where the phase locking mechanism ensures reliable locking to a specific angular phase, and an operation phase where the hydraulic phase changing mechanism enables timing adjustment. This segmentation allows each mechanism to optimize its function without compromising the other
Solution Approach 2:
The system dynamically switches between the phase locking mechanism and the hydraulic phase changing mechanism based on operational requirements. During starting, the locking mechanism is active; during operation, the hydraulic control is activated. This dynamic transition maintains reliability when needed while preserving adjustability when required
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
This approach enhances engine startability by reducing the impact of residual hydraulic oil on valve timing advancement and ensures quicker locking to a specific phase, improving engine starting efficiency.
Implementation Method 1
a hydraulic phase changing mechanism for changing valve timing of an internal combustion engine by selectively supplying and discharging hydraulic oil to and from an phase advancing chamber and a phase retarding chamber
Data Source
AI summary
A controller for a variable valve actuation device is provided. The controller prevents the startability of an internal combustion engine from being degraded. An electronic controller (91) performs a phase advancing control at engine starting to advance valve timing (VT) by oil pressure of an phase advancing chamber (37) and oil pressure of a phase retarding chamber (38) provided in a phase changing mechanism (30) if a residual oil amount (Q) is greater than or equal to a reference oil amount (QA) at engine starting. In addition, when the valve timing (VT) reaches an intermediate angular phase (VTmdl), the valve timing (VT) is held in the intermediate angular phase (VTmdl) by oil pressure of the phase changing mechanism (30).