Hydrocarbon Injection Control for Diesel Particulate Filter Regeneration
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Solution Overview
Problem
Existing systems for regenerating diesel particulate filters (DPF) face challenges in controlling the maximum amount of hydrocarbons injected into the exhaust system to prevent hydrocarbon slip, which can cause excessive DPF temperature, temperature hysteresis, and catalyst site blocking, especially during transient engine operating conditions.
Innovation Solution
A method and system that calculate the maximum allowable hydrocarbons for injection upstream of the diesel oxidation catalyst (DOC) based on the mass flow rate of exhaust gas and oxygen, ensuring that the hydrocarbons do not exceed a calculated threshold to prevent hydrocarbon slip, using sensors and an electronic control module to determine the optimal hydrocarbon injection rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hydrocarbons are injected into the exhaust system to raise temperatures for DPF regeneration, then DPF regeneration is enabled, but hydrocarbon slip occurs causing excessive DPF temperature, temperature hysteresis, and catalyst site blocking
Solution Approach 1:
The system dynamically calculates the maximum allowable hydrocarbon injection rate by changing the parameter of oxygen mass flow rate threshold. The control module adjusts the hydrocarbon injection rate based on real-time oxygen measurements, ensuring that combustion occurs completely in the DOC while preventing hydrocarbon slip. This parameter-based control allows the system to adapt to varying engine operating conditions and maintain optimal regeneration temperatures without causing harmful effects.
2Object-affected harmful factors
If calibration tables are used to control hydrocarbon injection, then maximum hydrocarbon amount is limited, but the control does not account for transient engine operating conditions
Solution Approach 1:
The system implements a feedback control mechanism where the control module continuously monitors the actual oxygen mass flow rate through sensors and compares it against the calculated threshold. Based on this feedback, the system dynamically adjusts the hydrocarbon injection rate in real-time, adapting to transient engine operating conditions. This feedback mechanism replaces static calibration tables with a dynamic control strategy that responds to actual sensor data, enabling the system to handle varying operating conditions effectively.
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
Effectively limits hydrocarbon slip, preventing DPF overheating and catalyst site blocking, while allowing for DPF regeneration during varying engine conditions by accurately determining the maximum hydrocarbon injection amount based on real-time exhaust and oxygen flow rates.
Implementation Method 1
provide hydrocarbons, typically in the form of diesel fuel but other fuels or hydrocarbon sources may be utilized, to the exhaust system of the engine at a location upstream of the DOC such that the hydrocarbons will combust and raise temperatures within the DPF
Implementation Method 2
a diesel oxidation catalyst (DOC) as well as a diesel particulate filter (DPF) within an exhaust system of the diesel engine purposed to reduce the amount of NOx and particulate matter released into the atmosphere
Data Source
AI summary
A method of providing hydrocarbons to an engine exhaust for regenerating a diesel particulate filter within an exhaust system of a diesel engine. A mass flow rate of exhaust gas within an exhaust system is determined. A mass flow rate of oxygen within the exhaust gas entering the diesel oxidation catalyst is determined. A set point indicative of an allowable mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst is received. A hydrocarbon threshold that may be injected into the exhaust system is calculated. Hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst, wherein the injected hydrocarbons do not exceed the calculated threshold amount of hydrocarbons.