Variable Compression Ratio Control for Engine Fuel Efficiency
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Solution Overview
Problem
Existing engine technologies face challenges in further improving fuel efficiency, particularly in varying compression ratios to optimize fuel consumption across different engine loads.
Innovation Solution
A compression ratio control device that dynamically adjusts the compression ratio of the engine's combustion chamber based on real-time engine load and pressure detection, using a hydraulic mechanism to vary the top dead center position of the piston and thereby optimize fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the compression ratio is increased to improve fuel efficiency, then fuel consumption decreases, but the maximum combustion pressure increases beyond safe limits
Solution Approach 1:
The compression ratio is made variable rather than fixed, allowing it to be dynamically adjusted based on engine operating conditions. The piston rod position is changed to vary the compression ratio, enabling the system to optimize fuel efficiency while maintaining combustion pressure within safe limits through real-time adaptation.
Solution Approach 2:
The compression ratio parameter is changed dynamically based on engine load and combustion pressure conditions. By adjusting the compression ratio according to operating parameters, the system achieves improved fuel efficiency at low loads while preventing excessive combustion pressure at high loads.
2Reliability
If the compression ratio is decreased to reduce combustion pressure, then engine safety is improved, but fuel efficiency deteriorates
Solution Approach 1:
The compression ratio is made variable rather than fixed, allowing it to be dynamically adjusted based on engine operating conditions. This enables the system to maintain high compression ratios for fuel efficiency when combustion pressure is safe, and reduce compression ratio when pressure limits are approached, thereby ensuring engine safety without permanent loss of efficiency.
Solution Approach 2:
The compression ratio parameter is dynamically changed based on real-time monitoring of combustion pressure and engine load. This allows the system to optimize the balance between fuel efficiency and engine safety by adjusting the compression ratio according to actual operating conditions rather than using a conservative fixed value.
3Device complexity
If a fixed compression ratio is used to simplify the engine design, then device complexity is reduced, but fuel efficiency across varying loads cannot be optimized
Solution Approach 1:
The compression ratio is made variable through a mechanical adjustment mechanism involving the piston rod and crosshead. This dynamic capability allows the system to optimize fuel efficiency across different engine loads while maintaining relatively simple control through direct mechanical linkage rather than complex electronic systems.
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 enables improved fuel efficiency by maintaining the maximum combustion pressure within a predetermined limit across varying engine loads, thereby reducing fuel consumption and enhancing engine performance.
Implementation Method 1
a hydraulic mechanism is provided between a piston rod and a crosshead pin
Data Source
Figure 1
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Figure 2B
AI summary
A compression ratio control device (180) includes a compression ratio controller (182) configured to control a compression ratio of a combustion chamber (128) so that the maximum combustion pressure approaches a combustion pressure upper limit value (cylinder-internal-pressure upper limit value) based on a detection signal of a detector at least when an engine load is equal to or less than a predetermined load (engine full load).