Hydraulic Valve Control Arrangement for Delayed Closure
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Solution Overview
Problem
Existing control arrangements for gas exchange valves in piston engines fail to delay the closing of the valve effectively, particularly at low engine loads, which limits air intake and increases emissions due to insufficient boost pressure.
Innovation Solution
A control arrangement with a chamber and piston device connected to the camshaft and valve mechanism, where hydraulic medium flows into the chamber during valve opening and is throttled out during closing, allowing for adjustable control of the piston device's speed and movement, using a feed and discharge conduit with a throttling device to delay the valve closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the valve is closed early before bottom dead centre to minimize emissions, then emissions are reduced, but air intake is insufficient due to low boost pressure at low engine loads
Solution Approach 1:
The patent applies dynamics by making the valve closing timing adjustable rather than fixed. The hydraulic control arrangement allows the valve closing timing to be dynamically changed based on engine operating conditions (load and speed). At low loads, the valve closes later to improve air intake, while at high loads it closes earlier to reduce emissions, thus resolving the contradiction between these two requirements.
Solution Approach 2:
The patent changes the timing parameter of valve closure based on engine operating conditions. By using hydraulic pressure control, the closing timing parameter can be varied continuously according to load and speed, allowing optimization of both air intake and emissions control under different operating conditions rather than being constrained by a fixed timing.
2Speed
If hydraulic medium is discharged quickly from the chamber space, then the piston device returns quickly and valve closing is prompt, but air intake is reduced due to insufficient delay in closing
Solution Approach 1:
The discharge speed of hydraulic medium is made dynamic rather than fixed. The control arrangement allows the discharge rate to be adjusted based on engine operating conditions, enabling the system to slow down valve closing when beneficial for air intake while maintaining quick closing when needed for performance and emissions control.
3Device complexity
If a simple hydraulic control arrangement is used, then device complexity is low, but selective operation for delayed closing cannot be achieved
Solution Approach 1:
The patent introduces a control arrangement that acts as an intermediary between the camshaft and valve mechanism. This intermediary component (the hydraulic control arrangement with chamber and piston device) enables selective and adjustable valve closing control without requiring complete redesign of the valve actuation system, thus adding adaptability while maintaining reasonable complexity.
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 improves engine performance across a wide load and revolution range by allowing delayed valve closure, optimizing air intake and reducing emissions, while maintaining simplicity and reliability.
Implementation Method 1
hydraulic medium is arranged to flow into the space, when the valve is being opened, and out of the space, when the valve is being closed
Implementation Method 2
When the discharge conduit comprises a flow throttling device, the adjustability of the operation of the control arrangement can be improved considerably
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A control arrangement (5) for a gas exchange valve in a piston engine (1) adapted between the camshaft (4) of the engine and the valve mechanism, which control arrangement comprises a body part (51) and a chamber (52) arranged therein, into which chamber a connection for hydraulic medium opens and in which a piston device is arranged in force transmission connection with the camshaft and the valve mechanism. The connection (58; 58.1, 58.2, 58.3, 58.3') for hydraulic medium opens to a space (59) in the chamber, which space increases as the piston device (53) moves in the opening direction of the valve, whereby hydraulic medium is arranged to flow into the space, when the valve is being opened, and out of the space, when the valve is being closed.