Variable Compression Connecting Rod Hydraulic Module
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Solution Overview
Problem
Internal combustion engines with fixed compression ratios face inefficiencies in the part-load range due to limited adjustable compression ratios, leading to issues like 'knocking' and incomplete resetting of connecting rod adjustments, which affect operational stability and longevity.
Innovation Solution
A connecting rod with an eccentric adjusting device and a hydraulic module featuring a switchover valve with check valves and throttles, allowing direct unthrottled fluid transfer from the GKS to the MKS chamber during low compression, and controlled fluid flow to prevent damage and ensure stability during switching between compression states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic fluid is supplied to both cylinders through separate lines with check valves, then the connecting rod achieves variable compression capability, but the acceleration of hydraulic fluid columns generates pressure differences that cause drifting and unstable operation
Solution Approach 1:
The patent merges the inlet lines for both cylinders into a common inlet line, allowing hydraulic fluid to be supplied to both the GKS chamber and MKS chamber through a single shared pathway. This eliminates the separate fluid columns that caused differential pressure and drifting, while the check valves integrated into the switchover valve maintain one-way flow control for variable compression operation.
Solution Approach 2:
The common inlet line acts as an intermediary that equalizes pressure distribution to both chambers. By providing a shared hydraulic pathway, the system eliminates the pressure differences that arose from separate supply lines, preventing the drifting phenomenon while maintaining the ability to adjust compression ratio through the switchover valve.
2Ease of operation
If the connecting rod uses separate inlet lines for GKS and MKS chambers, then each chamber can be controlled independently, but the system becomes more complex and expensive
Solution Approach 1:
The patent combines multiple inlet lines into a single common inlet line that supplies hydraulic fluid to both GKS and MKS chambers. This reduces the number of separate hydraulic passages required in the connecting rod, simplifying manufacturing and reducing cost, while the switchover valve with integrated check valves maintains independent control capability through its internal valve mechanisms.
3Speed
If hydraulic fluid flows unthrottled from GKS to MKS chamber during switching, then switching speed increases, but pressure differences may cause instability
Solution Approach 1:
The check valves are pre-positioned within the switchover valve mechanism, ready to activate immediately when pressure differential occurs during chamber switching. This preliminary positioning ensures that as soon as fluid begins flowing from GKS to MKS chamber, the check valve automatically controls the flow direction, enabling fast switching while maintaining stability through automatic pressure equalization.
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 configuration enhances positional stability, reduces fluid consumption, and allows for faster switching between compression states, improving the connecting rod's operational efficiency and extending its service life by preventing 'drifting' and ensuring stable hydraulic prestressing.
Implementation Method 1
A check valve is assigned to each of the cylinders, which, arranged in the inlet, enables hydraulic fluid to be fed into the cylinders and prevents hydraulic fluid from being discharged from the cylinders
Implementation Method 2
The changeover valve has a movable piston which can be shifted into a first switch position or a second switch position, the cylinders being connected in such a way that hydraulic fluid can be routed from the first cylinder into the second cylinder in the first switch position
Implementation Method 3
a hydraulic module with a switching valve for controlling a hydraulic fluid flow of the connecting rod for an internal combustion engine with variable compression with an eccentric adjusting device for adjusting an effective connecting rod length
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3~4
AI summary
The invention relates to a hydraulic module (10) with a switching valve (9) for controlling a hydraulic fluid flow of a connecting rod (1) for a variable-compression internal combustion engine with an eccentric adjusting device for adjusting the effective connecting rod length, wherein the eccentric adjusting device has at least a first cylinder (2) and a second cylinder (3) as hydraulic chambers and wherein both an inlet (4, 5) for supplying hydraulic fluid to the cylinders (2, 3) and an outlet (7, 8) for draining hydraulic fluid from the cylinders (2, 3) are provided. Each cylinder (2, 3) is associated with a check valve (14, 15) which, arranged in the inlet (4, 5), allows hydraulic fluid to be supplied to the cylinders (2, 3) and prevents hydraulic fluid from being drained from the cylinders (2, 3).The changeover valve (9) has a movable piston (11) which can be selectively moved into a first switching position (S1) or a second switching position (S2). The cylinders (2, 3) are connected such that in the first switching position (S1) hydraulic fluid can flow from the first cylinder (4) into the second cylinder (5). The invention further relates to a connecting rod with a hydraulic module.