Browse Topic: Diesel particulate filters
The automobile industry is going through one of the most challenging times, with increased competition in the market which is enforcing competitive prices of the products along with meeting the stringent emission norms. One such requirement for BS6 phase 2 emission norms is monitoring for partial failure of the component if the tailpipe emissions are higher than the OBD limits. Recently PM (soot) sensor is employed for partial failure monitoring of DPF in diesel passenger cars.. PM sensor detects soot leakage in case of DPF substrate failure. There is a cost factor along with extensive calibration efforts which are needed to ensure sensor works flawlessly. This paper deals with the development of an algorithm with which robust detection of DPF substrate failure is achieved without addition of any sensor in the aftertreatment system. In order to achieve this, a thermodynamic model of DPF substate was created using empirical relations between parameters like exhaust flow rate, exhaust
Recent legislations require very low soot emissions downstream of the particulate filter in diesel vehicles. It will be difficult to meet the new more stringent OBD requirements with standard diagnostic methods based on differential sensors. The use of inexpensive and reliable soot sensors has become the focus of several academic and industrial works over the past decade. In this context, several diagnostic strategies have been developed to detect DPF malfunction based on the soot sensor loading time. This work proposes an advanced online diagnostic method based on soot sensor signal projection. The proposed method is model-free and exclusively uses soot sensor signal without the need for subsystem models or to estimate engine-out soot emissions. It provides a comprehensive and efficient filter monitoring scheme with light calibration efforts. The proposed diagnostic algorithm has been tested on an experimentally validated simulation platform. 2D signatures are generated from soot
Thermal management in off road vehicles is critical because it directly or indirectly affects engine performance, fuel economy, safety, and emission. With the introduction of stringent exhaust emission norms such as the EU stage V and EPA Final Tier 4, modern engines use a Diesel Particulate Filter (DPF) to trap the soot particles present in the exhaust gases. These soot particles are burned using a process called regeneration where skin temperature of DPF increases beyond 400 °C. Situation becomes more worst when the vehicle is shutdown just after the regeneration, where the coolant fan is off and there is no active airflow. Hot air gets trapped and start increasing under hood temperature, affecting the performance of other sub systems like air intake, electrical components, aftertreatment sensors etc. There are several ways to manage this heat load. Normally the heat built up in the under-hood compartment escape to the environment by two paths - convection and radiation. This
To meet stringent emission norms and commercial vehicle customer demands, the selection of an after-treatment system (ATS) plays a considerable role. Therefore, the selected ATS should substantially reduce nitrogen oxide emission by proper decomposition of ammonia and particulate matter without significantly increasing the thermal stress on DPF. Though the BS-VI after-treatment architecture is derived from EURO-VI, only a certain level of technology for the vehicle operating conditions in India can be implemented. However, numerous vehicle operating condition challenges in the Indian market must be explicated. Correspondingly, it should be addressed with a robust durability validation methodology to enhance the ATS product performance in challenging environments. This paper discusses SCR catalysts emission performance and ammonia decomposition durability validation methodology for commercial vehicles. In addition, during various vehicle duty cycle conditions, the effectiveness of DPF
Major share of Small Commercial Vehicles (SCV) applications is operated in city conditions with frequent stops and short driving distance. Drivers will often operate these SCV with loads that exceed their rated specifications. Such driving profiles are particularly observed in food, e-commerce delivery, garbage collection vehicles which are driven inside the city. During Diesel Particulate Filter (DPF) regeneration events in these conditions, it is a challenge to maintain light-off temperature of oxidation catalyst. This may lead to prolonged regeneration durations with multiple regeneration interrupts and poor regeneration efficiency. Frequent engine start operations and lower passive regeneration result in a low regeneration interval. The extended DPF regeneration duration in combination with a low regeneration interval will result in high oil dilution. The study focuses on identifying such driving profiles and defining counter measures to improve the regeneration performance. This
The move away from fossil fuels and the diversification of the primary energy sources used are imperative both in terms of mitigating global warming and ensuring the political independence of the Western world. For the industries of agriculture and forestry, it is possible to secure the basic energy supply through their own yield. The use of vegetable oil is a possibility to satisfy the energy requirements for agricultural machines both autonomously and sustainably. Up to now, rapeseed has been the most important plant for oil production in Western Europe. In the EU, rapeseed oil is currently credited with up to 60% fossil CO2 savings compared to conventional diesel fuel. As a result, since 2018, rapeseed oil is no longer considered as biofuel in the EU. However, if cultivation and processing are completely based on renewable energy sources, up to 90% of fossil CO2 emissions can be saved in the future. This also applies to rapeseed oil, which is a by-product of animal feed production
To reach close to zero tailpipe NOx emissions, a double-SCR (selective catalytic reduction) system is proposed. In that, the first SCR unit would be placed upstream of the diesel particulate filter (DPF) and the second SCR unit downstream of DPF. This study focused on the experiments of the first SCR unit. The experiments were conducted utilizing a new, 4.4-liter heavy duty diesel engine that was connected to a research facility for studying after-treatment systems in controlled environment. Three different SCR’s: a vanadium-based SCR (V-SCR), a copper-based SCR (Cu-SCR) and a vanadium-based SCR including an ammonia slip catalyst (V-SCR+ASC) were studied. Studies were done at different exhaust temperatures from 215°C to 350°C. Emissions of NO, NO2, NH3, N2O, CO, CO2 and hydrocarbons were measured by FTIR. Particulate emissions (PM, PN) were studied as a part of the experiments. The results showed that the three SCR units performed differently. The performance of the V-SCR catalyst was
Concerns about the harmful exhaust emissions of internal combustion engines have imposed the employment of aftertreatment devices to reduce their impacts both on health and environment. System modeling of engine and aftertreatment devices is required not only to provide an accurate assessment of the engine and aftertreatment devices performances as single elements but also to quantify the complex interaction of these components from a thermo fluid perspective. The work focuses on development of a model capable of predicting temporal and spatial evolution of thermo-fluid quantities and chemical species in a diesel oxidation catalyst (DOC). The developed model allows to investigate the influence of thermal characteristics and gas composition on the evolution of the phenomena occurring in the device which deeply reflect on the particulate filter behavior during regeneration phase. A hybrid approach has been implemented to predict molar fractions and temperatures in the monolith under
This document describes a fuel-consumption test procedure that utilizes industry accepted data collection and statistical analysis methods to determine the difference in fuel consumption between vehicles with a gross vehicle weight of more than 10000 pounds. This test procedure can be used for an evaluation of two or more different vehicles but is not to be used to evaluate a component change. Although on-road testing is allowed, track testing is the preferred method because it has the greatest opportunity to minimize weather and traffic influences on the variability of the results. All tests shall be conducted in accordance with the weather constraints described within this procedure and shall be supported by collected data and analysis. This document provides information that may be used in concert with SAE Recommended Practices SAE J1264, SAE J1252, SAE J1321, and SAE J2966, as well as additional current and future aerodynamic and vehicle performance SAE standards
Supercharging a single-cylinder diesel engine has proved to be a viable methodology to reduce engine-out emissions and increase full-load torque and power. The increased air availability of the supercharger (SC) system helps to inject more fuel quantity that can improve the engine's full-load brake mean effective pressure (BMEP) without elevating soot emissions. However, the increased inlet temperature of the boosted air and the availability of excess oxygen can pose significant challenges to contain oxides of nitrogen (NOx) emissions. Hence, it is important to investigate the potential NOx reduction options in supercharged diesel engines. In the present work, the potential of low-pressure exhaust gas recirculation (LP EGR) was evaluated in a single-cylinder supercharged diesel engine for its benefits in NOx emission reduction and impact on other criteria emissions and brake specific fuel consumption (BSFC). A mass-production single-cylinder diesel engine was used for the present work
Heavy Duty Vehicle (HDV) Diesel emission regulations are set to be tightened in the future. The introduction of PN PEMS testing for Euro VI-e, and the expected tightening of PM/NOx targets set to be introduced by CARB in the US beyond 2024 are expected to create challenging tailpipe PN conditions for OEMs. Additionally, warranty and the useful life period will be extended from current levels. Improved fuel efficiency (reduction of CO2) also remains an important performance criteria. Furthermore, future non-road diesel emission regulations may follow tighten HDV diesel emission regulations contents, and non-road cycles evaluation needs to be considered as well for future. In response to the above tightened regulation, for Diesel Particulate Filter (DPF) technologies will require higher PN filtration performance, lower pressure drop, higher ash capacity and better pressure drop hysteresis for improved soot detectability. Additionally, thermal management of aftertreatment system has
As governmental agencies focus on low levels of the oxides of nitrogen (NOx) emissions compliance, new off-road applications are being reviewed for both regulated and unregulated emissions to understand the technological challenges and requirements for improved emissions performance. The California Air Resources Board (CARB) has declared its intention to pursue more stringent NOX standards for the off-road market. As part of this effort, CARB initiated a program to provide a detailed characterization of emissions meeting the current Tier 4 off-road standards [1]. This work focused on understanding the off-road market, establishing a current technology emissions baseline, and performing initial modeling on potential low NOx solutions. This paper discusses a part of this effort, focuses on the emissions characterization from two non-road engine platforms, and compares the emissions species from different approaches designed to meet Tier 4 emissions regulations. The engine platforms
Noble metal based Diesel Particulate Filters (DPF) are efficient aftertreatment devices to reduce the PM emissions of diesel engine at present. Because of the high cost of noble metal, it is necessary to develop base metal soot combustion catalyst. In this work, CeO2-MnOx nanoparticles and nanorods catalysts were prepared by coprecipitation method using different precipitants. The crystal morphology of CeO2-MnOx nanomaterials was identified by a scanning electron microscope. The nitrogen physisorption and hydrogen temperature-programmed reduction results suggest that CeO2-MnOx nanorods have smaller specific surface area and greater redox capacity than CeO2-MnOx nanoparticles. The temperature programmed oxidation (TPO) tests were performed to evaluate the catalytic activity of the catalysts for soot oxidation. Results show that the CeO2-MnOx nanorods catalyst exhibit higher soot oxidation activity than CeO2-MnOx nanoparticles. Afterwards, the prepared CeO2-MnOx materials were loaded on
This paper discusses design and optimization process for the integration of exhaust manifold with turbocharger for a 3 cylinder diesel engine, simulation activities (CAE and CFD), and validation of manifold while upgrading to meet current BS6 emissions. Exhaust after-treatment system needs to be upgraded from a simple DOC (Diesel Oxidation Catalyst) to a complex DOC+sDPF (Selective catalytic reduction coated on Diesel Particulate Filter) to meet the BS6 emission norms for this engine. To avoid thermal losses and achieve a faster light-off temperature in the catalyst, the exhaust after-treatment (EATS) system needs to be placed close to the engine - exactly at the outlet of the turbocharger. This has given to challenges in packaging the EATS. The turbocharger in case of BS4 is placed near the 2nd cylinder of the engine, but this position will not allow placing the BS6 EATS. Hence, the turbocharger position must be shifted to such an extent that it is placed before the first cylinder
This SAE Aerospace Recommended Practice (ARP) is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances
The Bharat Stage VI emission norms in India is driving the use of more complex after treatment systems for diesel engines, to meet the stringent emission limits. The after-treatment system typically includes theSelective Catalytic Reduction (SCR) catalyst and the Diesel Oxidation Catalyst (DOC) - Diesel Particulate Filter (DPF) systems to reduce engine out emissions of Nitrogen Oxides (NOx), hydrocarbons (HC), and particulates respectively. For a durable functioning of the aftertreatment system, cleaning of these components at regular intervals is required, the process termed as ‘regeneration’. The most common industry technique for regeneration is to use the existing injectors in the engine, to dose the extra fuel which is burnt in the DOC for regeneration. This has been a cost effective and simpler technique compared to the external hydrocarbon dosing system. But the tradeoff involved with this in-cylinder dosing technique is the risk of fuel in oil (FIO). The extra fuel injected
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