Engine Fuel Reforming Device Suppresses Knocking
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Solution Overview
Problem
Premixed compression ignition engines face challenges in suppressing knocking or accidental fires due to fluctuations in EGR gas temperature and composition, making it difficult to control combustion effectively.
Innovation Solution
The engine incorporates a fuel reforming device connected to the intake and EGR pipes, with a reforming cylinder that adiabatically compresses a mixture of intake air and EGR gas, and a primary fuel injection device that injects fuel at specific strokes, assisted by an auxiliary fuel injection device, to uniformly mix fuel with intake air and control temperature, thereby reforming fuel into lower hydrocarbon fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EGR gas is mixed with intake air at predetermined timing to suppress knocking or accidental fire, then combustion control is improved, but the effectiveness is insufficient due to fluctuations in EGR gas temperature and composition
Solution Approach 1:
The patent changes the temperature parameter of EGR gas by introducing a cooling mechanism. The EGR gas is cooled before being mixed with intake air, which stabilizes the temperature and composition of the mixture. This parameter change ensures consistent combustion control effectiveness regardless of fluctuations in original EGR gas conditions.
Solution Approach 2:
The patent introduces cooled EGR gas as an intermediary substance between the original hot EGR gas and the intake air. By cooling the EGR gas first, it serves as a stable mediator that consistently suppresses knocking and accidental fire without being affected by temperature fluctuations in the original exhaust gas.
2Productivity
If fuel is uniformly and leanly mixed with intake air for premixed compression ignition, then combustion efficiency is improved, but knocking or accidental fire occurs due to variations in operational conditions
Solution Approach 1:
The patent applies preliminary anti-action by cooling the EGR gas before it mixes with the fuel-intake air mixture. This pre-cooling action counteracts the potential harmful effect of hot EGR gas causing knocking or accidental fire, allowing the fuel to be uniformly and leanly mixed without risking combustion instability.
Solution Approach 2:
The patent converts the potentially harmful hot EGR gas into a beneficial cooled medium. By cooling the EGR gas, it transforms from a source of knocking and accidental fire into a effective suppressor of these phenomena, while still maintaining its role in combustion control and efficiency enhancement.
3Reliability
If EGR ratio is increased to suppress knocking, then combustion stability is improved, but additional cooling capacity is required to manage EGR gas heat
Solution Approach 1:
The patent segments the EGR gas flow path to include a dedicated cooling section. By separating the cooling function from the mixing function, the system can handle higher EGR ratios effectively. The EGR gas is cooled in a distinct stage before being introduced to the intake air-fuel mixture, managing the heat load systematically.
Solution Approach 2:
The patent performs preliminary cooling of EGR gas before it enters the mixing stage with intake air and fuel. This preliminary action removes excess heat from the EGR gas in advance, enabling higher EGR ratios to be used for improved combustion stability without overwhelming the system with thermal energy that could cause knocking or require excessive cooling capacity.
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 solution effectively suppresses knocking and accidental fires by uniformly mixing EGR gas with fuel, cooling the reforming fuel, and ensuring efficient fuel reforming, allowing for stable premixed compression self-ignition operations.
Implementation Method 1
a reforming cylinder that adiabatically compresses a mixture of intake air and EGR gas
Implementation Method 2
a reforming fuel intercooler configured to cool the mixture discharged from the fuel reforming device is provided in the exhaust pipe
Data Source
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AI summary
Provided is an engine with which knocking and misfiring can be suppressed and which is capable of operation by means of premixed compression self-ignition. This engine (1) is equipped with a reforming air cylinder (16), which is a fuel reforming device. An intake pipe (12) and an EGR pipe (27) are connected to the reforming air cylinder (16) via a supply pipe (25), and the reforming air cylinder is provided with a primary fuel injection device (20), which is connected to the intake pipe (12) via an exhaust pipe (28), and injects fuel into the mixed gas of intake air and exhaust air supplied to the reforming air cylinder (16) through the supply pipe (25).