Assisted Compression Ignition Engine with Dual Spark Plugs
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Solution Overview
Problem
Gasoline engines face challenges in achieving low-speed torque performance comparable to diesel engines while managing CO2 emissions and pollutant emissions, particularly at low loads and high speeds, due to the difficulty of autoignition of gasoline fuel.
Innovation Solution
An internal combustion engine design featuring at least two ignition devices in the combustion chamber, with control means to activate these devices for assisted compression ignition, initiating two flame cores to facilitate autoignition and control heat release distribution between flame propagation and compression ignition phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ignition device is used to initiate flame core, then the device complexity is reduced, but the ability to trigger autoignition process is insufficient
Solution Approach 1:
The ignition system is segmented into multiple independent ignition devices (at least two) positioned at different locations in the combustion chamber. Each ignition device independently initiates a flame core, and their combined effect ensures reliable autoignition triggering. This segmentation resolves the contradiction by distributing the ignition function across multiple points rather than relying on a single device.
2Adaptability or versatility
If gasoline fuel is used, then the fuel availability and global distribution are improved, but the autoignition difficulty and low-speed torque performance deteriorate
Solution Approach 1:
The combustion parameters are changed by using multiple ignition devices to create multiple flame cores that propagate simultaneously. This changes the pressure and temperature evolution in the combustion chamber, enabling gasoline to achieve autoignition-like combustion characteristics. The result is improved low-speed torque performance while maintaining gasoline fuel usage, resolving the contradiction between fuel availability and torque performance.
3Productivity
If compression ratio is increased to facilitate autoignition, then the combustion efficiency is improved, but the risk of knocking and engine durability deteriorate
Solution Approach 1:
Preliminary action is taken by using multiple ignition devices to initiate flame cores before the combustion chamber reaches extreme compression ratios. The flame propagation from multiple sources pre-heats and prepares the air-fuel mixture, enabling controlled combustion at moderate compression ratios. This prevents knocking while maintaining combustion efficiency, resolving the contradiction between productivity and reliability.
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 design enhances combustion efficiency, reduces emissions, and improves engine performance across a broader range of operating conditions by optimizing combustion timing and heat release distribution, achieving better stability and flexibility in engine operation.
Implementation Method 1
a combustion mode by assisted compression ignition... initiate two flame cores, at separate positions in the combustion chamber, which makes it easier to trigger the autoignition process
Implementation Method 2
To allow gasoline to autoignite, the pressure and temperature conditions in the combustion chamber must be optimal
Implementation Method 3
a flame core is initiated by the spark from the spark plug which propagates in the air/fuel mixture and when the temperature and pressure conditions in the combustion chamber have increased sufficiently
Data Source
AI summary
An internal combustion engine includes a combustion chamber with a cylinder head, a cylinder, and a piston. The internal combustion engine also includes at least one intake valve and at least one exhaust valve that are connected to the combustion chamber, a fuel injector that injects fuel into the combustion chamber, at least two ignition devices arranged in the combustion chamber, and control means that control the valves, the injector, and the ignition means. The control means operate the engine according to different combustion modes including a controlled ignition combustion mode, a compression ignition combustion mode, and an assisted compression ignition combustion mode. The control means activate the ignition means in the assisted compression ignition combustion mode.