SPCCI Engine Combustion Control for Noise Reduction
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Solution Overview
Problem
Compression autoignition in engines leads to increased pressure variation and combustion noise, which affects fuel economy and noise levels.
Innovation Solution
A combustion mode combining Spark Ignition (SI) and Compression Ignition (CI) combustion, known as SPCCI, where a spark plug ignites the air-fuel mixture by flame propagation, enhancing chamber temperature for autoignition, thereby reducing pressure variation and noise. This mode, controlled by a controller, adjusts valve timing and fuel injection to optimize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If compression autoignition is performed to improve fuel economy, then fuel economy is improved, but pressure variation increases and combustion noise increases
Solution Approach 1:
The patent combines spark ignition (SI) and compression ignition (CI) into a hybrid combustion mode called SPCCI. The spark plug initiates combustion to reduce pressure variation and noise, while compression autoignition continues to improve fuel economy. This merging of two ignition methods resolves the contradiction between fuel economy and combustion noise.
Solution Approach 2:
The patent changes the combustion parameters by controlling the ignition timing and fuel injection timing to achieve optimal SPCCI combustion. By adjusting these parameters, the system maintains low pressure variation and combustion noise while preserving fuel economy benefits.
2Object-generated harmful factors
If the temperature in the combustion chamber is reduced to extend the SI combustion period, then combustion noise is reduced, but the combustion efficiency may be affected
Solution Approach 1:
The patent uses preliminary spark ignition to start the combustion process before compression autoignition occurs. This preliminary action ensures that combustion begins in a controlled manner with lower pressure variation, then continues efficiently through compression autoignition, maintaining both low noise and high efficiency.
Solution Approach 2:
The patent ensures continuous combustion by transitioning from spark ignition to compression autoignition without interruption. The SI combustion starts the process and CI combustion continues it, maintaining useful action throughout the combustion stroke while managing noise and 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
The SPCCI combustion mode reduces combustion noise while improving fuel economy by controlling the timing and amount of fuel combustion, ensuring efficient engine operation across varying load conditions.
Implementation Method 1
The SI combustion causes flame propagation that starts by forcibly igniting air-fuel mixture in a combustion chamber
Implementation Method 2
The CI combustion starts by compression autoignition of air-fuel mixture in a combustion chamber
Data Source
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AI summary
This control apparatus for an engine includes an engine (1), an injector (6), a spark plug (25), an intake electric S-VT (23), an exhaust electric S-VT (24), and a controller (ECU 10). The controller outputs a control signal to at least one of the intake electric S-VT and the exhaust electric S-VT so as to perform valve control of opening an intake valve (21) when an exhaust valve (22) is open, and then outputs a control signal to the spark plug at predetermined ignition timing such that, after air-fuel mixture is ignited and combustion is started, unburned air-fuel mixture is combusted by autoignition.