Intake Manifold Vacuum Control via Variable Valve Duration
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Solution Overview
Problem
Current intake vacuum management systems in internal combustion engines fail to effectively control air pressure within the intake manifold across varying engine loads, leading to inefficiencies in air and fuel flow.
Innovation Solution
A vacuum actuated mechanism with a valve actuation assembly that operates in multiple modes based on pressure limits, adjusting the opening duration of intake valves during intake and compression strokes to optimize vacuum levels in the intake manifold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the intake valve opening duration is extended to increase vacuum in the intake manifold, then vacuum level is improved, but air and fuel flow control precision deteriorates
Solution Approach 1:
The valve actuation assembly dynamically adjusts the intake valve opening duration based on real-time vacuum level feedback. The system transitions between multiple operational modes (first mode for normal operation, second mode for enhanced vacuum) allowing continuous optimization of both vacuum level and air-fuel flow control precision under varying engine conditions.
Solution Approach 2:
The system changes the temporal parameter of valve opening duration based on vacuum level thresholds. By extending the opening duration in specific modes when vacuum levels are insufficient, and maintaining shorter durations in other modes for precise air-fuel control, the system optimizes the trade-off between vacuum generation and flow control precision.
2Reliability
If the valve actuation assembly operates in multiple modes to optimize vacuum levels, then intake vacuum management is improved, but device complexity increases
Solution Approach 1:
The valve actuation assembly incorporates a vacuum actuated mechanism that automatically responds to vacuum level conditions without requiring complex external control systems. The mechanism self-regulates by transitioning between operational modes based on internal vacuum feedback, reducing the need for additional actuators and control electronics while maintaining reliable vacuum management.
Solution Approach 2:
The valve actuation assembly performs multiple functions through a single integrated mechanism: it controls air-fuel flow during normal operation, generates vacuum when needed, and automatically transitions between operational modes. This multi-functionality reduces the need for separate systems and minimizes overall device complexity while improving vacuum management reliability.
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 solution allows for precise control of intake manifold pressure, enhancing engine efficiency by adjusting valve opening durations in response to operating pressures, thereby optimizing air and fuel flow across different engine loads.
Implementation Method 1
The valve actuation assembly may be operated in the first mode when an operating pressure in the vacuum chamber is below a predetermined limit and may be operated in the second mode when the operating pressure in the vacuum chamber is above the predetermined limit
Data Source
AI summary
An engine assembly may include an engine structure defining a first intake port in communication with a combustion chamber, an intake manifold, a vacuum actuated mechanism, a first intake valve, and a valve actuation assembly. The vacuum actuated mechanism may include a vacuum chamber in communication with the intake manifold. The first intake valve may open and close the first intake port. The valve actuation assembly may be engaged with the first intake valve and may be operated in first and second modes. The first mode may provide a first opening duration of the first intake valve during one of an intake stroke and a compression stroke of a piston located in the combustion chamber. The second mode may provide a second opening duration of the first intake valve that is different than the first opening duration, providing reduced intake manifold pressure.