Engine Cold Start NOx Reduction via Exhaust Brake and Fuel Timing
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Solution Overview
Problem
Current engine start methods result in undesired emissions, such as yellowish or brownish smoke, due to the production and release of NOx gases during cold starts, which are harmful to the environment and vehicle performance.
Innovation Solution
A method involving controlled fuel dosage with a delay relative to optimal combustion, utilizing an SCR catalytic converter to minimize NOx production and storage, and activating/deactivating an exhaust brake based on temperature and reducing agent levels to optimize emissions reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel dosage is optimized for combustion efficiency during engine start, then engine starting reliability is improved, but NOx emissions increase
Solution Approach 1:
The exhaust brake is activated before the engine start to pre-heat the SCR catalytic converter, ensuring it reaches the necessary temperature for NOx reduction before combustion begins. This preliminary action prepares the emissions treatment system in advance to handle the upcoming NOx generation during engine start.
Solution Approach 2:
The invention changes the timing parameter of fuel dosage by introducing a delay relative to optimal combustion. This delay reduces peak combustion temperature, thereby reducing NOx formation while still achieving reliable engine starting. The exhaust brake activation timing is also optimized to balance thermal heating needs against emissions reduction.
2Object-generated harmful factors
If exhaust brake is activated during engine start, then NOx emissions are reduced, but engine warming speed decreases
Solution Approach 1:
The exhaust brake activation is made dynamic rather than static. It is activated temporarily during the critical phase when the SCR catalytic converter needs heating, and then deactivated or reduced when the converter reaches sufficient temperature. This dynamic adjustment allows the system to balance emissions reduction with engine warming requirements at different stages of the start process.
Solution Approach 2:
The exhaust brake is activated in advance before the engine starts to quickly bring the SCR catalytic converter to operating temperature. This preliminary activation ensures the emissions treatment system is ready to function effectively as soon as combustion begins, even though it temporarily slows the overall warming process.
3Object-generated harmful factors
If SCR catalytic converter is used for NOx reduction, then emissions are cleaned, but system complexity increases
Solution Approach 1:
The SCR catalytic converter is designed to be self-sustaining through the exhaust brake heating process. The exhaust brake utilizes the engine's own exhaust gases to heat and activate the catalytic converter, eliminating the need for external heating systems or additional energy inputs. The system serves itself by using its waste exhaust to prepare its own emissions treatment capability.
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 effectively reduces NOx emissions and minimizes undesired smoke during engine starts, achieving a reliable and environmentally friendly cold start process by controlling fuel dosage and exhaust brake activation.
Implementation Method 1
an SCR catalytic converter, in which the reducer and NOx gas can react and are converted to nitrogen gas and water
Implementation Method 2
Application of an exhaust brake at an engine of a motor vehicle during starting of the engine, such as during the cold start of the engine, is currently known, in order in this way to achieve a more rapid warming of the engine and a post-treatment system
Data Source
AI summary
A method to reduce during the start of an engine undesired emissions from the engine, where an SCR catalytic converter for the cleaning of exhaust gases is arranged in an exhaust passage at the engine. The method includes controlling the dosage of fuel to the engine with a certain delay relative to what is the case during essentially optimal combustion in order to reduce the development of heat that results from the combustion of fuel through non-optimal combustion. Also a computer program product comprising program code to implement a method of reducing emissions. Also an arrangement to reduce during the start of an engine undesired emissions from the engine and a motor vehicle that is equipped with the arrangement.