A compact solid SCR system for NOx reduction in passenger cars and light duty trucks

MTZ worldwide ◽  
2003 ◽  
Vol 64 (6) ◽  
pp. 14-17 ◽  
Author(s):  
Michael Krüger ◽  
Patrick Nisius ◽  
Volker Scholz ◽  
Andreas Wiartalla
Keyword(s):  
Nox Reduction ◽  
Passenger Cars ◽  
Light Duty ◽  
Scr System

scholarly journals SCR systems for NOx reduction in heavy and light duty vehicles

2016 ◽  
Vol 164 (1) ◽  
pp. 32-36
Author(s):  
Piotr JAWORSKI ◽  
Sebastian JAROSIŃSKI ◽  
Azael CORTES CAPETILLO ◽  
Łukasz KAPUSTA ◽  
Adam ZIÓŁKOWSKI ◽  
...  
Keyword(s):  
Air Pollution ◽  
Automotive Industry ◽  
Urban Areas ◽  
Nox Reduction ◽  
Road Transport ◽  
Light Duty ◽  
Scr System ◽  
Light Duty Vehicles ◽  
Transport Emissions ◽  
System Designs

Air pollution has become an important worldwide problem. The European Commission credits road and water transport as the major source of NOx pollution, and of being responsible for around 50% of the total air pollution in urban areas. During the last decade, the use of SCR technologies have gained popularity as a method for NOx reduction, the technology is widely considered as one of the solutions for road transport emissions. This paper presents a review of the different SCR system designs derived from the various factors and regulations in the automotive industry which have influenced the technology, along with a parametric study of a proprietary SCR system for heavy duty application.

scholarly journals Numerical Optimization of a SCR System Based on the Injection of Pure Gaseous Ammonia for the NOx Reduction in Light-Duty Diesel Engines

2020 ◽  
Author(s):  
Augusto Della Torre ◽  
Gianluca Montenegro ◽  
Angelo Onorati ◽  
Tarcisio Cerri ◽  
Enrico Tronconi ◽  
...  
Keyword(s):  
Diesel Engines ◽  
Numerical Optimization ◽  
Nox Reduction ◽  
Gaseous Ammonia ◽  
Light Duty ◽  
Scr System

Characteristics of NOx Emission of Light-duty Diesel Vehicle with LNT and SCR system by Season and RDE Phase

2021 ◽  
pp. 146750
Author(s):  
Yongjoo Lee ◽  
Seungil Lee ◽  
Seunghyun Lee ◽  
Hoimyung Choi ◽  
Kyoungdoug Min
Keyword(s):  
Nox Emission ◽  
Light Duty ◽  
Scr System ◽  
Diesel Vehicle

Diesel Emission Test Stand for Advanced SCR Control

2015 ◽  
Author(s):  
Joe Noto ◽  
Athul Radhakrishnan ◽  
Ye Sun ◽  
Josh Ferreira ◽  
Marc Compere
Keyword(s):  
Control Systems ◽  
Fuel Economy ◽  
Nox Reduction ◽  
Test Stand ◽  
Diesel Emissions ◽  
Diesel Generator ◽  
Light Duty ◽  
Nox Sensor ◽  
Diesel Emission ◽  
Tier 3

The combination of increasingly challenging emissions regulations and impending Corporate Average Fuel Economy (CAFE) standards of 54.5 mpg by 2025 presents auto makers with a challenge over the next 10 years. The most promising technologies currently available for meeting high fuel economy and low emissions regulations are increased hybridization, turbo downsizing, and increased Diesel engine implementation. Combining these into a hybrid turbo Diesel is an ideal transition technology for the very near future as battery and other alternative fuels become viable for widespread automotive use. This paper presents a Diesel emission test stand to improve Selective Catalytic Reduction (SCR) systems for light duty Diesel vehicles, particularly hybrid power systems that experience many start-stop events. Advanced modeling and control systems for SCR systems will further reduce tailpipe emissions below existing Tier structures and will prepare manufacturers to meet increasingly stringent Tier 3 standards beginning in 2017. SCR reduces oxides of Nitrogen, NO, and NO2, from otherwise untreated Diesel emissions. Scientific study has proved that inhaling this harmful exhaust gas is directly responsible for some forms of lung cancer and a variety of other respiratory diseases. In addition to EPA Tier emissions levels and CAFÉ standards, the On-Board Diagnostics (OBD) regulations require every vehicle’s emission control systems to actively report their status during all engine-on vehicle operation. Testing and development with production NOx sensors and production SCR components is critical to improving NOx reduction and for OEMs to meeting strict Tier 3 light duty emission standards. The test stand was designed for straightforward access to the NOx sensors, injector, pump and all exhaust components. A Diesel Particulate Filter (DPF) followed by a Diesel Oxidizing Catalyst (DOC) precedes the Selective Catalytic Reducer (SCR) injector, mixing pipe and catalyst. An upstream NOx sensor reads engine-out NOx and the downstream NOx sensor reports the post catalyst NOx levels. Custom fabrication work was required to integrate the SCR mechanical components into a simple system with exhaust components easily accessible in a repeatable, controlled laboratory environment. A Diesel generator was used in combination with a custom designed resistive load bank to provide variable NOx emissions according to the EPA drive cycles. A production exhaust temperature sensor was calibrated and integrated into the software test manager. Production automotive NOx sensors and SCR injector, pump and heaters were mounted on a production light duty vehicle exhaust system. The normalized nature of NOx concentration in parts per million (ppm) allows the small Diesel generator to adequately represent larger Diesels for controls development purposes. Both signal level and power electronics were designed and tested to operate the SCR pump, injector, and three Diesel Exhaust Fluid (DEF) heating elements. An Arduino-based Controller Area Network (CAN) communications network read the NOx Diesel emissions messages from the upstream and downstream sensors. The pump, injector, solenoid, and line heaters all functioned properly during DEF fluid injection. CAN and standard serial communications were used for Arduino and Matlab/Simulink based control and data logging software. Initial testing demonstrated partial and full NOx reduction. Overspray saturated the catalyst and demonstrated the production NOx sensor’s cross-sensitivity to ammonia. The ammonia was indistinguishable from NOx during saturation and motivates incorporation of a separate ammonia sensor.

scholarly journals Direct Measurement of Ammonia Storage on Passive SCR Systems for Lean Gasoline NOx Reduction Using Radio Frequency Sensing

2019 ◽  
Author(s):  
Paul Ragaller ◽  
Josh Mandelbaum ◽  
Luc Lapenta ◽  
Alexander Sappok ◽  
Josh Pihl ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Real Time ◽  
Gasoline Engine ◽  
Nox Reduction ◽  
Practical Implementation ◽  
Engine Operation ◽  
Ammonia Storage ◽  
Scr System ◽  
Lean Gasoline ◽  
Passive Scr

Abstract Lean gasoline engine operation provides clear efficiency benefits relative to conventional stoichiometric combustion approaches. One of the key hurdles to the widespread, practical implementation of lean gasoline combustion remains the challenge of lean NOx control. One of the potential approaches for controlling NOx emission from lean gasoline engines is the so-called passive selective catalytic reduction (SCR) system. In such systems, periods of rich operation generate ammonia over a three-way catalyst (TWC), which is then adsorbed on the downstream SCR and consumed during lean operation. Brief periods of rich operation must occur in response to the depletion of stored ammonia on the SCR, which requires reliable measurements of the SCR ammonia inventory. Presently, lean exhaust system controls rely on a variety of gas sensors mounted up- and downstream of the catalysts, and which only provide an indirect inference of the operation state. In this study, a radio frequency (RF) sensor was used to provide a direction measurement of the amount of ammonia adsorbed on the SCR in real-time. The RF sensor was calibrated and deployed on a BMW N43B20 4-cylinder lean gasoline engine equipped with a passive SCR system. Brief periods of rich operation performed at lambda values between 0.98 and 0.99 generated the ammonia, subsequently stored on the SCR for consumption during periods of lean operation. The experiments compared real-time measurements of SCR ammonia inventory from the RF sensor with estimates of ammonia coverage derived from exhaust gas composition measurements upstream and downstream of the catalyst. The results showed a high degree of correlation between the RF measurements and SCR ammonia storage inventory, and demonstrated NOx conversion efficiencies above 98%, confirming the feasibility of the concept. Relative to stoichiometric operation, lean-gasoline operation resulted in fuel efficiency gains of up to 10%, which may be further improved through direct feedback control from the RF sensor to optimize lean–rich cycling based on actual, measured SCR ammonia levels.

Sign in / Sign up

Export Citation Format

Share Document