Variable Compression Ratio Engine Cylinder Bleed Valve
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Solution Overview
Problem
Existing variable compression ratio engine systems face challenges in efficiently starting engines with high compression ratios, particularly at low ambient temperatures, due to increased oil viscosity and torque requirements exceeding starter motor capabilities, and previous heat recovery systems interfere with engine starting and fail to independently regulate heat recovery and combustion charge flow.
Innovation Solution
A method involving a cylinder bleed valve coupled to a bleed manifold and a turbine-generator, where combustion charge can be routed either through or around the turbine-generator based on engine conditions, such as start-up status and energy storage levels, to adjust compression ratio and improve starting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high compression ratio is used to increase combustion efficiency, then combustion efficiency is improved, but engine starting capability deteriorates due to excessive torque requirements
Solution Approach 1:
The patent applies a variable compression ratio mechanism that dynamically adjusts the compression ratio based on engine operating conditions. During start-up, the compression ratio is reduced to lower torque requirements and enable reliable starting. During normal operation, the compression ratio is increased to maximize combustion efficiency. This dynamic adjustment resolves the contradiction between high compression efficiency and start-up capability.
2Loss of energy
If heat recovery system is used to extract energy from combustion charge, then energy efficiency is improved, but engine starting operation is interfered with
Solution Approach 1:
The control system detects engine start-up conditions and preemptively disables the heat recovery system before starting attempts. By anticipating the need for full starting torque and preventing energy extraction during start-up, the system avoids interfering with starting operation while maintaining energy recovery during normal operation.
Solution Approach 2:
The system uses feedback from engine operating condition sensors to dynamically control the heat recovery system. When start-up conditions are detected through feedback signals, the control system automatically disables the heat recovery mechanism. This feedback-based control ensures energy recovery occurs only when it will not compromise starting capability.
3Reliability
If compression ratio is varied to improve start-up operation, then starting capability is improved, but combustion efficiency during high load may deteriorate
Solution Approach 1:
The variable compression ratio system dynamically adapts the compression ratio to match engine load conditions. During start-up and low-load operation, the compression ratio is reduced to improve starting capability. During high-load operation, the compression ratio is increased to maximize combustion efficiency and power output. This dynamic adaptation resolves the contradiction between start-up improvement and high-load efficiency.
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 approach enhances engine starting efficiency by reducing torque requirements and optimizing energy extraction from combustion charge, preventing interference with start-up operations while improving overall engine performance and efficiency.
Implementation Method 1
the bleed manifold including an igniter positioned upstream of a turbine-generator
Implementation Method 2
the bleed manifold including an igniter positioned upstream of a turbine-generator
Data Source
AI summary
A method for operating an engine system is provided, the method may include varying a compression ratio of a cylinder by selectively releasing combustion charge from the cylinder through a cylinder bleed valve of a cylinder head, the cylinder bleed valve coupled to a bleed manifold with a turbine-generator, and varying combustion charge flow through a turbine-generator bypass conduit bypassing the turbine-generator based on engine operating conditions. In this way, the compression ratio may be varied by selectively bleeding combustion charge from the cylinder based on engine operating conditions to promote better engine performance. Additionally, the combustion charge bleed from the cylinder can routed around a turbine-generator to increase combustion efficiency during certain operating conditions, such as during start-up, to further improve engine performance.