Hydraulic Module for Variable Compression Connecting Rod
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Solution Overview
Problem
Internal combustion engines with fixed compression ratios face inefficiencies during part-load operations due to limited adjustable compression ratios, leading to issues like 'knocking' and incomplete resetting of connecting rod adjustments, which affect the stability and service life of the eccentric adjustment mechanism.
Innovation Solution
A hydraulic module with an eccentric adjusting device featuring a first and second cylinder, check valves, and a stepped piston with a circumferential groove, allowing unthrottled hydraulic fluid flow from the GKS chamber to the MKS chamber, enhancing positional stability and reducing 'drifting' effects by prestressing the MKS chamber and utilizing band check valves for compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed compression ratio is used to prevent knocking under full load, then engine reliability is improved, but engine efficiency during part-load operation deteriorates
Solution Approach 1:
The patent implements variable compression ratio capability through dynamic adjustment of the connecting rod length using a hydraulic module with eccentric adjustment device. The system transitions from fixed to variable compression ratio, allowing the engine to optimize performance across different operating conditions while maintaining reliability.
2Power
If the compression ratio is increased for full load operation, then power output is improved, but engine knocking occurs during full load operation
Solution Approach 1:
The system dynamically adjusts compression ratio based on operating conditions. During full load operation, the higher compression ratio is engaged to maximize power output, while during part-load operation, the compression ratio is reduced to prevent knocking, thus resolving the contradiction between power output and knocking prevention.
3Speed
If the connecting rod adjustment is not completely reset, then adjustment speed is improved, but positional stability and service life of the eccentric adjustment mechanism deteriorate
Solution Approach 1:
The patent extracts and addresses the resetting issue by providing an active hydraulic return path through the stepped piston mechanism. The circumferential groove in the stepped piston creates a dedicated flow path that ensures complete resetting of the hydraulic chambers, eliminating the drift phenomenon and ensuring positional stability while maintaining acceptable adjustment speeds.
4Reliability
If check valves are used to prevent hydraulic fluid leakage, then positional stability is improved, but hydraulic fluid flow resistance increases
Solution Approach 1:
The stepped piston with circumferential groove acts as an intermediary element that mediates between the check valve function and flow resistance. It provides a controlled return path for hydraulic fluid that reduces the pressure differential across check valves during resetting operations, thereby reducing flow resistance while maintaining positional stability through the check valve mechanism.
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 solution improves the stability and rigidity of the connecting rod's eccentric adjustment, reducing 'drifting' and extending service life by ensuring complete resetting and maintaining high compression ratios without throttling, thus enhancing engine efficiency and reliability.
Implementation Method 1
a first and a second cylinder (4, 5) as hydraulic chambers, each with an inlet (6, 7) for supplying hydraulic fluid to the cylinders (4, 5) via a supply line (8) and an outlet (11, 12)
Implementation Method 2
controlling a hydraulic fluid flow of a connecting rod
Implementation Method 3
Each cylinder is equipped with a check valve that allows hydraulic fluid to flow into the cylinders and prevents it from flowing out
Implementation Method 4
an eccentric adjusting device (40) for adjusting an effective connecting rod length
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The invention relates to a hydraulic module (10) for controlling a hydraulic fluid flow of a connecting rod (1) for a variable-compression internal combustion engine, comprising an eccentric adjusting device (40) for adjusting the effective connecting rod length, wherein the eccentric adjusting device (40) has at least a first cylinder (4) and a second cylinder (5) as hydraulic chambers. On the module side, at least one piston (17) movable in a housing (3) is provided, which can be selectively moved into a first switching position (S1) or a second switching position (S2). Each cylinder (4, 5) is associated with a check valve (18, 19) which allows hydraulic fluid to be supplied to the cylinders (4, 5) and prevents hydraulic fluid from being discharged from the cylinders (4, 5).The cylinders (4, 5) are connected such that in the second switching position (S2) hydraulic fluid can flow from the first cylinder (4) to the second cylinder (5) via a channel (32) in the hydraulic module (10). The invention further relates to a connecting rod (1) with a hydraulic module (10).