Dual Intake Valve Timing for Homogeneous SI Engine Combustion
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Solution Overview
Problem
Existing spark-ignition internal combustion engines face issues of non-homogeneous air-fuel mixture and reduced air mass intake due to asymmetric flow fields and swirl vortex generation, leading to reduced combustion efficiency and increased harmful emissions.
Innovation Solution
Simultaneously opening both intake valves during the first half of the intake stroke to create a tumble motion, followed by opening one valve during the second half to generate a swirl motion, with fuel injection occurring during the first opening period to ensure a symmetric flow field and maximize air mass intake, while using a variable actuation system to control intake valve opening and closing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct injection is used to improve combustion efficiency and reduce emissions, then fuel economy and power output are improved, but combustion stability deteriorates due to poor atomization and mixture formation
Solution Approach 1:
The injection system is divided into two separate systems: a direct injection system for fuel economy and a port injection system for combustion stability. This segmentation allows each system to perform its specialized function optimally without compromising the other.
Solution Approach 2:
The patent combines direct injection and port injection systems into a single dual-injection system. The port injection unit and direct injection unit work together to achieve both improved fuel economy and maintained combustion stability that neither system could achieve alone.
2Power
If direct injection is used to improve combustion efficiency, then power output increases, but atomization quality deteriorates leading to poor mixture formation
Solution Approach 1:
The port injection unit acts as an intermediary that pre-mixes fuel with air before the fuel enters the combustion chamber. This pre-mixing process improves atomization quality and mixture formation, enabling the direct injection system to achieve higher power output without sacrificing atomization precision.
3Reliability
If port injection is used to improve combustion stability, then mixture formation improves, but fuel injection timing flexibility deteriorates
Solution Approach 1:
The injection timing function is segmented between two systems: the port injection system handles early injection timing for stable mixture formation, while the direct injection system handles late injection timing for optimized combustion control. This segmentation provides comprehensive timing flexibility while maintaining combustion stability.
4Device complexity
If a single injection system is used to simplify the structure, then device complexity is reduced, but injection coverage and functional versatility deteriorate
Solution Approach 1:
The dual-injection system provides multi-functionality by enabling different injection strategies for different operating conditions. The system can switch between port injection, direct injection, or combined injection modes to optimize performance across various engine loads and speeds, achieving universal applicability.
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
Enhances combustion efficiency and reduces harmful emissions by maximizing air mass intake and optimizing kinetic energy generation, ensuring a homogeneous air-fuel mixture and anti-knocking effects, even at high compression ratios.
Implementation Method 1
introducing a first charge of fuel into the intake port of a combustion chamber of a spark-ignition internal combustion engine with a multi-port fuel injection system
Implementation Method 2
introducing a second charge of fuel directly into the combustion chamber
Implementation Method 3
spark-ignition internal combustion engine
Data Source
Figure 1~2
Figure 3
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AI summary
A spark-ignition internal combustion engine includes, for each cylinder, two intake valves (VA, VB), at least one fuel injector and a spark plug. The two inlet valves (VA, VB) are actuated by an electronically controlled hydraulic actuation device (8) or by a device with electromagnetic or electropneumatic actuators. The actuation device is configured to carry out, in each operating cycle of the cylinder, at least under certain operating conditions of the engine, a first opening period, in which both the intake valves (VA, VB) open when the piston of the respective cylinder is in proximity of the 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, during the first opening period, when both intake valves are open.