Fuel Oxygen Ratio Control for Diesel PM Reduction
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Solution Overview
Problem
Diesel engines face challenges in reducing particulate matter (PM) emissions without the use of diesel particulate filters (DPFs), as the required fuel oxygen content varies with engine design and operating conditions, potentially penalizing fuel economy.
Innovation Solution
A system comprising a pressure control valve (PCV) and a volume control valve (VCV) is positioned in the fuel rail and high-pressure pump, respectively, to adjust the fuel ratio of higher and lower oxygenated fuels in response to PM levels, allowing for dynamic adjustment of fuel oxygen content to maintain PM below target levels without a DPF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a diesel particulate filter (DPF) is used to reduce PM emissions, then PM emission levels are reduced, but drivetrain cost, complexity, and weight increase
Solution Approach 1:
The invention extracts and removes the DPF component from the exhaust system, replacing it with a fuel system modification that introduces higher oxygen-containing fuel directly into the combustion chamber. This eliminates the need for the DPF while achieving PM reduction through improved combustion chemistry.
Solution Approach 2:
The invention changes the chemical composition parameter of the fuel by introducing higher oxygen-containing fuel (such as ethanol-blended diesel or oxygenated diesel). This parameter change modifies the combustion process to reduce soot formation at the source, eliminating the need for aftertreatment devices like DPFs.
2Object-affected harmful factors
If fuel oxygen content is increased to reduce PM emissions, then PM emission levels are reduced, but fuel economy is reduced
Solution Approach 1:
The invention implements a dynamic fuel management system with a variable ratio fuel mixer that can adjust the proportion of high-oxygen fuel in real-time. The system responds to engine operating conditions and PM sensor feedback, using high-oxygen fuel only when needed for PM reduction, thereby optimizing fuel economy while controlling emissions.
Solution Approach 2:
The system incorporates a PM sensor that provides feedback on exhaust particulate levels, which the controller uses to dynamically adjust the high-oxygen fuel injection rate. This closed-loop control ensures that high-oxygen fuel is introduced only at levels necessary to maintain PM compliance, avoiding unnecessary fuel economy penalties.
3Object-affected harmful factors
If high oxygen-containing fuel is introduced to meet emissions standards, then PM emissions are reduced, but the system must account for varying engine designs and operating conditions
Solution Approach 1:
The system employs dynamic control that continuously monitors engine operating conditions (load, speed, temperature) and PM levels, adjusting the high-oxygen fuel injection rate accordingly. This enables the system to adapt to varying engine designs and operating conditions while maintaining consistent PM reduction performance.
Solution Approach 2:
The controller dynamically adjusts multiple parameters including the high-oxygen fuel to total fuel ratio, injection timing, and injection duration based on engine operating conditions. These parameter changes enable the system to optimize PM reduction across different engine designs and operating scenarios.
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 maintains PM levels below targets across various engine designs and conditions while preserving fuel economy, reduces CO2 emissions, and lowers manufacturing costs by eliminating the need for DPFs and related systems, enabling engine downsizing and reducing the frequency of DPF regeneration.
Implementation Method 1
Combustion of a fuel having a higher fuel oxygen content may promote more uniform combustion and reduce fuel-rich regions within the combustion chambers, where soot and PM tend to form
Data Source
AI summary
A method may comprise: positioning a pressure control valve (PCV) at an outlet of a fuel rail; positioning a volume control valve (VCV) at an inlet of a high pressure pump; and in response to an exhaust particulate matter (PM) level deviating from a target PM level, adjusting a fuel ratio of a first fuel and a second fuel delivered to an engine, and opening one of the PCV and the VCV. In this way, the fuel oxygen content may be adjusted to maintain a PM at or below a target level without a DPF over a broad range of engine designs and operating conditions, while maintaining fuel economy.