Variable Valve Actuator for Adaptive Engine Timing
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Solution Overview
Problem
Conventional cam-driven valve actuation systems in internal combustion engines are inflexible and struggle to adapt to varying operating conditions, such as cold starts, leading to difficulties in combustion and reduced engine efficiency due to fixed actuation timing, which is not suitable for emission reduction measures like the late intake Miller cycle.
Innovation Solution
A valve actuation system incorporating a fluid actuator, bi-directional control valve, accumulator, and relief valve to dynamically control intake valve timing, allowing for flexible actuation and adaptation to different engine conditions by selectively holding the valve open or closed, and draining fluid to adjust pressure and prevent inefficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional cam-driven valve actuation system is used, then the engine structure is simple and reliable, but the valve actuation timing is fixed and cannot adapt to different operating conditions
Solution Approach 1:
The patent applies dynamics by replacing the static cam-driven actuation system with a dynamic hydraulic actuator system that can adjust valve timing in real-time. The hydraulic actuator responds to control signals from the electronic control unit, enabling continuous adjustment of valve actuation timing based on operating conditions such as engine speed, load, and temperature.
Solution Approach 2:
The patent substitutes the mechanical cam-driven system with a hydraulic actuation system controlled by electronic signals. This replacement allows for more precise and flexible control of valve timing while reducing mechanical wear and enabling adaptive behavior that was not possible with pure mechanical systems.
2Productivity
If a late intake Miller cycle is implemented with a fixed cam arrangement, then engine efficiency is improved, but the engine becomes difficult to start when cold
Solution Approach 1:
The hydraulic actuator system dynamically adjusts valve timing based on engine temperature and operating conditions. During cold starts, the system can provide conventional timing to ensure reliable combustion, then transition to Miller cycle timing once the engine is warmed up, optimizing efficiency without sacrificing cold start reliability.
Solution Approach 2:
The system changes the valve actuation timing parameters based on engine temperature and operating conditions. The electronic control unit monitors engine state and adjusts the hydraulic actuator accordingly, switching between conventional timing (for cold starts) and Miller cycle timing (for efficient operation).
3Object-generated harmful factors
If emission reduction measures such as gas recirculation are implemented, then emissions are reduced, but engine efficiency decreases
Solution Approach 1:
The variable valve timing system dynamically optimizes valve overlap and duration to work synergistically with emission reduction systems. By precisely controlling when intake and exhaust valves open and close, the system can enhance the effectiveness of gas recirculation and other emission control measures while minimizing their negative impact on engine efficiency.
Solution Approach 2:
The system adjusts valve timing parameters to optimize the balance between emissions control and efficiency. By modifying valve lift, duration, and timing, the system can improve the effectiveness of emission reduction strategies while maintaining acceptable engine performance.
4Productivity
If the cam shape is modified to implement late intake Miller cycle, then valve actuation timing is adjusted for efficiency, but the system loses flexibility to adapt to different operating conditions
Solution Approach 1:
Instead of a fixed cam shape, the patent uses a dynamic hydraulic actuator system that can continuously adjust valve timing. This allows the engine to operate in Miller cycle mode for efficiency when conditions are favorable, while switching to conventional timing when adaptability is needed, such as during cold starts or transient conditions.
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 system enhances engine efficiency and emission compliance by allowing for adaptive valve timing, improving combustion in cold conditions and maintaining high efficiency during normal operation, while reducing emissions by allowing for maximum gas substitution in dual fuel engines.
Implementation Method 1
A fluid actuator is operably connected to the intake valve and is configured to selectively hold the intake valve in the open position, selectively hold the intake valve in the closed position, and selectively hold the intake valve at various positions between the open position and the closed position
Implementation Method 2
A bi-directional control valve is configured to control a flow of fluid between the source of fluid and the fluid actuator
Implementation Method 3
An accumulator may be in fluid communication with the fluid passageway
Implementation Method 4
a restrictive orifice may be disposed between the accumulator and the fluid passageway to restrict a flow of fluid between the accumulator and the fluid passageway
Implementation Method 5
A relief valve may be in fluid communication with the fluid passageway and moveable between a closed position to prevent a flow of fluid therethrough to create a high pressure circuit in the valve actuation system and an open position to allow a flow of fluid therethrough to create a low pressure circuit in the valve actuation system
Data Source
AI summary
A valve actuation system is provided. A fluid actuator is configured to selectively prevent a valve from moving to a particular position. A source of fluid is in fluid communication with the fluid actuator. A bi-directional control valve is configured to control a flow of fluid between the source of fluid and the fluid actuator. A fluid passageway connects the bi-directional control valve with the fluid actuator. A relief valve is in fluid communication with the fluid passageway and moveable between a closed position to prevent a flow of fluid therethrough to create a high pressure circuit in the valve actuation system and an open position to allow a flow of fluid therethrough to create a low pressure circuit in the valve actuation system.