Engine Control Apparatus for SPCCI Combustion Noise Reduction
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Solution Overview
Problem
In combustion engines, pressure variation during ignition can lead to increased combustion noise, and existing techniques struggle to control compression autoignition timing effectively, resulting in reduced thermal efficiency and potential torque loss.
Innovation Solution
The implementation of a SPCCI (Spark Controlled Compression Ignition) combustion mode, which combines SI and CI combustion, where a spark plug ignites the air-fuel mixture by flame propagation, enhancing chamber temperature for autoignition, while controlling the CI combustion period to reduce noise and improve fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If compression ignition is used 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 generate heat, which then promotes autoignition of the air-fuel mixture. This merging allows the system to achieve the fuel economy benefits of CI while using the controlled flame propagation of SI to reduce pressure variation and combustion noise.
Solution Approach 2:
The patent controls the timing of spark ignition to optimize the temperature rise rate in the combustion chamber. By adjusting the spark timing parameter, the system ensures that autoignition occurs at the desired moment while controlling the rate of pressure increase, thereby reducing combustion noise while maintaining fuel economy improvements.
2Object-generated harmful factors
If spark ignition is used to reduce combustion noise, then combustion noise is reduced, but autoignition timing cannot be controlled and thermal efficiency decreases
Solution Approach 1:
The system uses feedback control to adjust spark timing based on engine operating conditions. By monitoring parameters such as intake air temperature, engine load, and rotation speed, the control unit optimizes the spark timing to ensure that the heat from spark-induced combustion promotes autoignition at the optimal moment, thereby maintaining thermal efficiency while controlling combustion noise.
Solution Approach 2:
The patent dynamically adjusts the spark timing parameter according to engine operating conditions. By changing the spark timing based on intake air temperature, load, and rotation speed, the system ensures that autoignition occurs at the desired timing, thereby maintaining thermal efficiency while using flame propagation to reduce combustion noise.
3Object-generated harmful factors
If compression ignition timing is delayed to reduce combustion noise, then combustion noise is reduced, but torque output decreases
Solution Approach 1:
The spark plug performs preliminary ignition before compression ignition would naturally occur. This preliminary action generates heat that promotes autoignition at the optimal timing, ensuring that the main combustion event occurs at the desired moment to maintain torque output while the controlled flame propagation reduces combustion noise.
4Reliability
If intake air temperature is increased to promote autoignition, then autoignition timing is improved, but combustion becomes unstable and knocking increases
Solution Approach 1:
The system controls the spark timing parameter as a function of intake air temperature. By adjusting the spark timing based on intake air temperature, the system ensures that the heat from spark-induced combustion promotes autoignition at the desired timing without causing premature ignition or knocking, thereby maintaining combustion stability while achieving reliable autoignition timing.
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 reduces combustion noise and enhances fuel economy by managing the autoignition timing and temperature, ensuring efficient combustion without torque loss.
Implementation Method 1
a spark plug ignites the air-fuel mixture by flame propagation
Implementation Method 2
combustion by compression autoignition
Implementation Method 3
air-fuel mixture is combusted by autoignition
Implementation Method 4
heat generation by the SI combustion enhances the temperature in the combustion chamber
Data Source
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AI summary
This control apparatus of an engine includes an engine (1), a state quantity setting device (23, 24, 43, 48, 54), an injector (6), a spark plug (25), and a controller (ECU 10). The controller outputs a control signal to the spark plug (25) at a predetermined ignition timing such that, after air-fuel mixture is ignited and combustion is started, unburned air-fuel mixture is combusted by autoignition, and the controller advances an ignition timing when the temperature before start of compression in a combustion chamber (17) is to be reduced.