Dual Nozzle Engine Cold Start Fuel Injection Strategy
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Solution Overview
Problem
When starting from a cold state, internal combustion engines face challenges with fuel injection, including fuel adherence to intake port surfaces, dilution, and inefficient vaporization, leading to increased fuel consumption and exhaust smoke due to low injection pressure and uneven fuel distribution.
Innovation Solution
An engine with first and second nozzles for direct and port injections, respectively, where the control unit initially injects fuel into odd-numbered and even-numbered cylinders alternately using either nozzle set based on ignition order, ensuring sufficient pressure and vaporization before switching to all-cylinder injections by the first nozzles until specific operating conditions are met, then switching to port injections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel is injected into the intake port when the engine is cold, then fuel vaporization is facilitated, but fuel adheres to the intake port surface and is diluted, leading to increased fuel consumption
Solution Approach 1:
The patent divides the engine cylinders into two groups (odd-numbered and even-numbered cylinders) and uses different injection strategies for each group during the initial start phase. This segmentation allows alternating between port injection and direct injection, enabling the system to benefit from port injection's vaporization advantage while mitigating its fuel loss through adhesion.
Solution Approach 2:
The patent applies different injection methods to different locations (intake port vs. cylinder) and different cylinder groups based on their specific needs. Port injection is used for cylinders where vaporization is the priority, while direct injection is used for cylinders where fuel delivery efficiency is critical, creating localized optimal conditions.
2Temperature
If fuel injection pressure is increased to facilitate fuel vaporization in cold state, then vaporization improves, but it takes time to build sufficient residual pressure
Solution Approach 1:
The patent performs preliminary fuel injection into the intake port before the engine starts rotating. This preliminary action delivers fuel to the intake port where it can begin vaporizing in advance, so that when the engine actually starts and direct injection begins, the fuel is already in a vaporized or partially vaporized state, eliminating the need to wait for pressure buildup.
3Speed
If fuel is injected into all cylinders simultaneously, then combustion is achieved quickly, but fuel distribution becomes uneven and atomization is insufficient
Solution Approach 1:
The patent segments the cylinder group into odd-numbered and even-numbered subsets, injecting fuel into each subset at different times rather than all cylinders simultaneously. This sequential segmentation ensures that each cylinder receives adequate fuel pressure and atomization while still achieving rapid overall combustion by alternating between the two groups.
Solution Approach 2:
The patent employs periodic alternating injection between odd-numbered and even-numbered cylinders. This periodic action allows the fuel injection system to maintain high pressure by cycling through cylinders in a controlled sequence, ensuring proper atomization while achieving rapid combustion through the alternating pattern.
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 fuel consumption and stabilizes engine rotation by ensuring proper atomization and utilization of fuel, minimizing unnecessary fuel use and exhaust smoke, while maintaining high fuel pressure and efficient combustion.
Implementation Method 1
making the pressure of fuel injected from the fuel injection valve for the cylinder injection in the cylinder high
Implementation Method 2
the pressure of fuel injected from the first nozzles reaches sufficiently high pressure, fuel injected from the first nozzles is appropriately atomized
Implementation Method 3
vaporization of fuel is facilitated by making the pressure of fuel injected from the fuel injection valve for the cylinder injection in the cylinder high
Implementation Method 4
even if the pressure of injected fuel is low and the diameter of fuel particles is large, the fuel is vaporized before it is supplied to the cylinder
Implementation Method 5
a combustion state is not stabilized in order that evaporation of fuel does not proceed
Data Source
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AI summary
An engine (1) includes first nozzles (Di1 to Di4), second nozzles (Pi1 to Pi4) and a control unit (2). The first nozzles (Di1 to Di4) are arranged in cylinders (#1 to #4), and inject fuel directly into the cylinders (A1 to A4) respectively. The second nozzles (Pi1 to Pi4) are arranged in intake ports (B1 to B4) of the cylinders (#1 to #4), and inject fuel into the intake ports respectively. The control unit (2) controls fuel injection of the first nozzles (Di1 to Di4) and the second nozzles (Pi1 to Pi4). When the engine (1) is started, the control unit (2) performs initial fuel injection by one of the first and second nozzles into the cylinders having odd-number of initial ignition order, and performs initial fuel injection by the other one of the first and second nozzles into the cylinders having even-number of initial ignition order.