Combustion Engine Mode Optimization via Valve Timing
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Solution Overview
Problem
Internal combustion engines, particularly spark-ignited engines, face inefficiencies in energy conversion and higher emissions compared to diesel engines, especially at low load conditions, and diesel engines have drawbacks such as high NOx emissions and soot production.
Innovation Solution
A system with a controller that selects between spark ignition, low temperature combustion, and diffusion flame modes based on engine temperature and load conditions, adjusting valve timing and fuel injection to optimize combustion efficiency and reduce emissions, including increasing delay between intake and exhaust valve openings for low temperature mode and direct injection for diffusion flame mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If spark ignition is used, then the engine can operate at low temperatures, but combustion efficiency is low and emissions are high
Solution Approach 1:
The system dynamically switches between spark ignition mode and compression ignition mode based on real-time engine temperature and load conditions. The controller adjusts valve timing and fuel injection strategies according to the selected mode, enabling the engine to adapt its combustion characteristics to operating conditions and optimize both efficiency and emissions performance.
Solution Approach 2:
The patent changes combustion parameters by switching ignition modes and adjusting valve timing durations. In compression ignition mode, the intake valve closing timing is advanced and exhaust valve opening timing is delayed to trap hot residuals, raising compression temperature to enable auto-ignition without spark, thereby improving combustion efficiency at appropriate operating temperatures.
2Loss of energy
If diesel compression ignition is used, then energy efficiency is improved, but NOx emissions and soot production increase
Solution Approach 1:
The system dynamically selects between spark ignition and compression ignition modes based on operating conditions. At low load conditions, spark ignition mode is used to reduce NOx and soot emissions, while at high load conditions where compression ignition is selected, energy efficiency is improved. This dynamic switching resolves the contradiction by allowing the engine to optimize for emissions when possible and for efficiency when necessary.
3Temperature
If intake valve opening duration is reduced to create delay, then residual gas temperature increases and auto-ignition is induced, but valve timing complexity increases
Solution Approach 1:
The controller pre-programmes valve timing strategies for different combustion modes. When compression ignition mode is selected, the controller automatically implements the predetermined valve timing sequence that creates the necessary delay between intake valve closing and exhaust valve opening to trap hot residuals and achieve auto-ignition. This preliminary preparation reduces the perceived complexity during operation.
Solution Approach 2:
The system uses feedback from temperature sensors and load sensors to determine when to switch between combustion modes. The controller continuously monitors engine conditions and adjusts valve timing accordingly, using feedback loops to maintain optimal residual gas temperature for auto-ignition while managing the complexity through automated control algorithms.
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
Improves combustion efficiency by up to 15% and reduces carbon dioxide and soot emissions, enhancing fuel economy and minimizing environmental impact.
Implementation Method 1
The delay increases a residual gas temperature in the combustion chamber and induces auto-ignition of fuel in the combustion chamber
Implementation Method 2
a spark ignition mode is selected based on the combustion engine being colder than the predetermined temperature and the low load conditions on the combustion engine, the spark ignition mode including instructions to apply a spark to combust fuel in the combustion chamber
Implementation Method 3
a diffusion flame mode is selected including instructions to apply direct injection of fuel into the combustion chamber for compression ignited combustion
Data Source
AI summary
Methods and systems are described for combustion engine mode optimization. The system includes a combustion engine, a fuel delivery system, and a controller communicatively coupled to the combustion engine and the fuel delivery system. The controller selects a low temperature combustion mode based on the combustion engine being warmer than a predetermined temperature and low load conditions on the combustion engine. The low temperature combustion mode includes instructions that reduces an intake valve opening duration and an exhaust valve opening duration. The controller reduces the intake valve opening duration and the exhaust valve opening duration to create a delay between an intake valve opening duration and an exhaust valve opening duration in response to selecting the low temperature combustion mode. The delay increases a residual gas temperature in the combustion chamber and induces auto-ignition of fuel in the combustion chamber.