Dual-Intake Spark-Ignition Engine for Stable Diluted Combustion
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Solution Overview
Problem
Existing spark-ignition internal combustion engines face challenges in achieving high combustion efficiency and stability with highly diluted mixtures, particularly under varying operating conditions, and struggle to maintain efficient combustion rates and reduce harmful emissions.
Innovation Solution
The engine employs a dual intake valve strategy with a first opening period creating tumble motions and a second opening period generating swirl motions, combined with centralized fuel injection to create a stoichiometric mixture near the spark plug and a diluted mixture near the cylinder walls, utilizing a variable actuation system to optimize air-fuel charge homogeneity and combustion rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high compression ratios are used to improve thermal efficiency, then fuel economy is improved, but nitrogen oxide emissions increase
Solution Approach 1:
The patent applies parameter changes by operating the engine at ultra-lean air-fuel ratios (λ=21-40) and controlling combustion phasing to achieve high thermal efficiency without the traditional high compression ratio approach. This changes the fundamental operating parameters to decouple efficiency gains from nitrogen oxide formation.
Solution Approach 2:
The patent uses local quality through three-dimensional spark plug positioning that creates localized high-temperature zones for efficient combustion while the overall charge remains ultra-lean. The spark plug is positioned to optimize local combustion characteristics without requiring globally high compression ratios that would increase nitrogen oxide emissions.
2Reliability
If three-dimensional spark plug combustion is used to improve cold-start performance, then cold-start capability is improved, but control complexity increases
Solution Approach 1:
The three-dimensional spark plug combustion system creates localized high-temperature zones by positioning the spark plug optimally within the combustion chamber. This local quality enhancement improves cold-start performance without requiring complex global system changes, as the focused energy delivery addresses the specific cold-start problem zone.
Solution Approach 2:
The patent incorporates feedback control through the ECU that monitors combustion conditions and adjusts spark timing and injection parameters in real-time. This feedback mechanism manages the complexity of three-dimensional combustion control by continuously optimizing parameters based on actual combustion feedback, making the complex system adaptable rather than rigid.
3Use of energy by moving object
If ultra-lean air-fuel ratios are used to reduce fuel consumption, then fuel economy is improved, but combustion stability deteriorates
Solution Approach 1:
The patent changes the parameter of air-fuel ratio to ultra-lean conditions (λ=21-40) while simultaneously changing combustion phasing and spark timing parameters to maintain stability. The combination of these parameter changes allows the system to achieve low fuel consumption without the combustion instability that would normally result from ultra-lean operation alone.
Solution Approach 2:
By positioning the spark plug in three-dimensional space to create localized high-temperature ignition zones, the system ensures reliable combustion initiation even in ultra-lean conditions. This local quality enhancement provides the stability needed for ultra-lean combustion to proceed reliably throughout the combustion chamber.
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 combustion stability and efficiency, reduces harmful emissions, and allows flexible operation between stratified and non-stratified combustion modes, with improved flame propagation and reduced heat losses to the cylinder walls.
Implementation Method 1
spark-ignition internal combustion engine
Implementation Method 2
piston-crank mechanism
Implementation Method 3
internal combustion engine
Implementation Method 4
expansion of combustion gases
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A spark-ignition internal combustion engine comprises, for each cylinder, two intake valves (VA, VB), at least one fuel injector and a spark plug. The two inlet valves (VA, VB) are operated by an electronically controlled hydraulic drive device (8) or by a device with electromagnetic or electropneumatic actuators. The actuating device is configured to carry out, in each operating cycle of the cylinder, at least under certain engine operating conditions, a first opening period, in which both the intake valves (VA, VB) open when the piston of the respective cylinder is in proximity of TDC and close when the piston is at an intermediate point in the descent from TDC to BDC, and a second opening period, in which only one intake valve (VA) opens when the piston of the respective cylinder is in proximity of the BDC and closes when the piston is ascending from BDC to TDC. In the second opening period the second intake valve (VB) remains closed. The fuel supply system is configured to perform at least one fuel injection, in each operating cycle of each cylinder, after said second opening period, when the piston of the respective cylinder is ascending from BDC to TDC.