Variable Compression Ratio Piston Pin Hydraulic Control
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Solution Overview
Problem
Current internal combustion engines face challenges in achieving high thermal efficiency and preventing abnormal combustion due to limited ignition timing advancement, which affects fuel efficiency and output, and diesel engines require complex and costly modifications for variable compression ratio control to meet emissions regulations.
Innovation Solution
A variable compression ratio device that uses a piston pin with interconnected plunger spaces and check valves to adjust the compression ratio by controlling oil supply to chambers, allowing the top dead center of the piston to move up and down, thereby implementing high or low compression ratios based on engine conditions through hydraulic pressure management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If ignition timing is advanced to improve thermal efficiency, then fuel efficiency is improved, but abnormal combustion occurs and engine damage may result
Solution Approach 1:
The patent changes the compression ratio parameter dynamically based on engine operating conditions. By adjusting the compression ratio rather than ignition timing, the system achieves improved fuel efficiency without causing abnormal combustion. The compression ratio is modified by changing the piston position through hydraulic pressure control of the eccentric cam mechanism.
2Use of energy by moving object
If compression ratio is increased to improve thermal efficiency, then fuel efficiency is improved, but knocking occurs and output deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of compression ratio based on real-time engine operating conditions. The system uses sensors to detect engine state and hydraulically controls the eccentric cam to modify piston position, thereby changing compression ratio dynamically. This allows optimization of fuel efficiency at low loads while maintaining high output at high loads without knocking.
3Adaptability or versatility
If piston position is controlled by rotating eccentric cam with hydraulic pressure, then compression ratio is adjusted, but structure becomes complex
Solution Approach 1:
The patent makes the piston pin serve multiple functions: it acts as both the connecting element between piston and connecting rod and as the housing for the hydraulic control mechanism. The piston pin contains plunger spaces and check valves that enable compression ratio adjustment, eliminating the need for separate control components and reducing overall structural complexity.
Solution Approach 2:
The hydraulic control mechanism is nested within the piston pin structure. The plunger spaces and check valves are integrated into the piston pin, creating a compact arrangement where the compression ratio control system is contained within the existing moving component, thereby reducing external 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 effectively improves fuel efficiency and engine output by dynamically adjusting compression ratios, reducing fuel consumption and preventing knocking, while simplifying the structure and reducing manufacturing costs compared to existing solutions.
Implementation Method 1
supplying oil to a first chamber or supplying the oil to a second chamber to get a top dead center of a piston to go up and down
Implementation Method 2
a return member elastically supporting the second plunger to one side
Data Source
AI summary
A variable compression ratio device may include a piston pin having first and second plunger spaces, a plunger device including a first plunger that is disposed to reciprocate in the first plunger space, a second plunger and a connection pipe that connects between the first and second plungers, a first check valve disposed in a first check space to move oil from a pipe passage to the first check space in a first direction, a second check valve disposed in a second check space to move the oil from the pipe passage to a second check space in a second direction; and a return member elastically supporting the second plunger to one side.