Variable Valve Train Damper for Pressure Fluctuation Control
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Solution Overview
Problem
Hydraulic valve control systems in variable valve train modules experience pressure fluctuations that lead to undesirable engine noise and vibration due to cyclical changes in pressure.
Innovation Solution
A damper system is introduced that includes a high pressure chamber, a control valve, and an orifice connecting the chamber to an open space, which allows hydraulic fluid to enter a created space when pressure exceeds a threshold, effectively increasing the chamber's volume and damping energy associated with pressure oscillations through hydraulic friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hydraulic valve control system is used to provide fully variable valve lift capabilities, then engine efficiency is improved, but pressure fluctuations produce engine noise and vibration
Solution Approach 1:
The patent introduces a damper as an intermediary component between the high pressure chamber and the hydraulic fluid system. The damper includes a piston and spring assembly that mediates pressure fluctuations by allowing controlled fluid displacement, thereby reducing noise and vibration while preserving the benefits of hydraulic valve control
Solution Approach 2:
The patent changes the physical parameters of the high pressure chamber by introducing a variable volume element (the damper). The damper's piston moves in response to pressure changes, dynamically altering the chamber's effective volume and thus changing the system's pressure characteristics to reduce harmful fluctuations
2Stress or pressure
If the high pressure chamber volume is increased to reduce pressure spikes, then pressure fluctuations are reduced, but the chamber's ability to provide precise hydraulic pushrod action is compromised
Solution Approach 1:
The patent applies a dynamic solution by introducing a movable piston in the damper that responds to pressure changes. The piston's position is not fixed but varies dynamically with pressure, allowing the system to maintain precision during normal operation while absorbing pressure spikes when needed
Solution Approach 2:
The damper is designed to activate only under specific conditions (when pressure exceeds a threshold), providing partial action rather than continuous intervention. The spring-loaded piston only engages when necessary to absorb pressure fluctuations, leaving the hydraulic system's precise action intact during normal operation
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
The damper reduces pressure spikes from 30 bar to 5-10 bar, minimizing engine noise and vibration by absorbing pressure increases and introducing hydraulic friction to stabilize pressure fluctuations.
Implementation Method 1
The orifice acts as a hydraulic friction component which dampens energy associated with pressure oscillations in the pressure chamber
Implementation Method 2
The orifice acts as a hydraulic friction component which dampens energy associated with pressure oscillations in the pressure chamber
Data Source
AI summary
A variable valve train module selectively controls the opening and closing of a valve of an engine. The variable valve train module includes a drive element configured to be driven by a cam which rotates on a camshaft, a pump which is driven by the drive element, and a hydraulic control unit. The hydraulic control unit is configured to control the engine valve. The hydraulic control unit has a high pressure chamber containing hydraulic fluid which is selectively pressurized by the pump. The hydraulic control unit also has a control valve which is configured to depressurize the high pressure chamber, and a damper which is configured to increase an effective volume of the high pressure chamber when a pressure in the high pressure chamber exceeds a threshold value.