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Technical Paper

An Investigation Into Transient Diesel Spray Development Using High Speed Imaging In A Novel Optical Pressure Chamber

2011-08-30
2011-01-1836
The fuel economy and emissions performance of a Diesel engine is strongly influenced by the fuel injection process. This paper presents early results of an experimental investigation into diesel spray development carried out in a novel in-house developed optical pressure chamber capable of operating at pressure up to 50 bar and temperatures up to 900 K. The spatial evolution of a diesel spray tends to experience many transitory macroscopic phenomena that directly influence the mixing process. These phenomena are not considered highly reproducible and are extremely short lived, hence recording and understanding these transient effects is difficult. In this study, high-speed backlight-illuminated imaging has been employed in order to capture the transient dynamics of a short signal duration diesel spray injected into incremental back pressures and temperatures reaching a maximum of 10 bar and 473 K respectively.
Technical Paper

Insights into Deposit Formation in High Pressure Diesel Fuel Injection Equipment

2010-10-25
2010-01-2243
The need to meet the US 2007 emissions legislation has necessitated a change in Diesel engine technology, particularly to the fuel injection equipment (FIE). At the same time as these engine technology changes, legislation has dictated a reduction in fuel sulphur levels and there has also been increased use of fatty acid methyl esters (FAME) or biodiesel as a fuel blending component. The combination of changes to the engine and the fuel has apparently led to a sharp rise in the number of reports of field problems resulting from deposits within the FIE. The problem is usually manifested as a significant loss of power or the engine failing to start. These symptoms are often due to deposits to be found within the fuel injectors or to severe fouling of the fuel filter. The characteristics of the deposits found within different parts of the fuel system can be noticeably different.
Technical Paper

A Study of the Parameters Ensuring Reliable Regeneration of a Sintered Metal Particulate Filter using a Fuel Borne Catalyst

2008-10-06
2008-01-2485
The operating cycle of many vehicles fitted with diesel particulate filters is such that soot accumulates within the filter and must periodically be oxidised. Work was carried out on a passenger car engine to elucidate how fuel borne catalyst (FBC) to soot ratio, oxygen mass flow rate, temperature and soot loading influence the oxidation rate of soot accumulated in a sintered metal filter (SMF). Results show that soot loading had a major influence; increased soot loading increased the oxidation rate. The other parameter had a smaller influence with increasing oxygen flow rate and FBC/soot ratio each increasing the oxidation rate.
Technical Paper

Metal Emissions, NO2 and HC Reduction from a Base Metal Catalysed DPF/FBC System

2006-04-03
2006-01-0420
Due to concerns over NO2 emissions from platinum catalysts a base metal catalysed diesel particulate filter (DPF) has been developed and used in combination with fuel borne catalysts (FBC). Results are presented showing reductions in HC, NOX, NO2, and PAH emissions along with an assessment of the emissions of metals used in the FBC and the catalysed DPF. This data is used to show the likely reduction in overall iron and other metal emissions as a result of using the catalysed DPF/FBC system. A similar system has also been assessed for durability for over 2000 hours when fitted to a bus in regular service in Switzerland.
Technical Paper

Practical Experience of Fitting DPFs to Buses in Chile

2005-05-11
2005-01-2146
Continuing research into the effect of vehicle emissions is driving legislation, which is increasingly being enacted to encourage the retrofitting of emissions control devices. Of particular concern are emissions of diesel particulate matter and nitrogen oxides. More recently the adverse effects of nitrogen dioxide in particular, have been highlighted. A programme of work is underway in Santiago to demonstrate the suitability of retrofitting diesel particulate filters (DPF) to urban buses. This paper presents data, including regulated and unregulated emissions, from a bus fitted with a DPF that relies on a fuel borne catalyst (FBC) to facilitate regeneration of the DPF.
Technical Paper

Retrofitting TRU-Diesel Engines with DPF-Systems Using FBC and Intake Throttling for Active Regeneration

2005-04-11
2005-01-0662
Transport Refrigeration Units (TRU) powered by small diesel engines emit high PM and cause locally high PM levels. The concomitant health risks spurred efforts to devise a cost-effective curtailment of these emissions. Diesel particulate filters (DPF) of ceramic honeycomb construction very efficiently trap PM emissions, even ultrafines in the lung penetrating size range of below 300 nm. A fuel borne catalyst (FBC) can facilitate trap regeneration, by lowering the exhaust temperature requirements, but cannot alone guarantee reliable regeneration under all operating conditions of the TRU. A Swiss development team together with industrial partners therefore developed a fully automatic active regeneration system for the California Air Resources Board.
Technical Paper

DPF Technology for Older Vehicles and High Sulphur Fuel

2005-01-19
2005-26-020
The most cost-effective way to reduce the level of diesel particulate emissions is to retrofit exhaust aftertreatment devices. While diesel oxidation catalysts will reduce the mass of particles emitted, they will not significantly reduce the number of ultrafine particles, that are considered the most harmful to health. Diesel Particulate Filters (DPFs) are therefore considered the most effective retrofit devices. One obstacle to the widespread adoption of DPFs is that many DPF technologies require low sulphur fuel. Using a Fuel Borne Catalyst (FBC) to facilitate regeneration of the DPF allows a sulphur tolerant DPF system to be produced.
Technical Paper

Retrofitting Urban Buses to Reduce PM and NO2

2004-06-08
2004-01-1939
In an attempt to improve ambient air quality, retrofit programmes have been encouraged; targeting reductions in PM emissions by means of diesel particulate filters (DPFs). However depending on the DPF design and operating conditions increased nitrogen dioxide (NO2) emissions have been observed, which is causing concern. Previous work showed that retrofitting a DPF system employing a fuel borne catalyst (FBC) to facilitate regeneration, reduced NO2 emissions. This paper outlines the investigation of a base metal coated DPF to enhance the reduction of NO2. Such a DPF system has been fitted to older technology buses and has demonstrated reliable field performance.
Technical Paper

Results From a ¼ Million km, Heavy-Duty Truck Trail, Using FBC Regenerated DPFs

2004-03-08
2004-01-0074
Diesel particulate filters (DPF), in conjunction with fuel borne catalysts (FBC) to facilitate regeneration, are now an accepted technology for passenger car application. Retrofitting of such systems has demonstrated the possibility of applying this technology to heavy-duty vehicles. To demonstrate the efficacy of DPF/FBC systems and to assess their affect on engine durability and economy, five heavy-duty trucks were fitted with DPF/FBC systems. After the completion of over ¼ million kms four trucks underwent a full engine strip-down and rating. This paper briefly reviews the installation of the systems and their effect on the regulated emissions, present details of the mileage accumulation and of the engine strip-downs. The conclusions drawn are that after a ¼ million km of use with the DPF/FBC systems the trucks had not suffered any abnormal deterioration and in fact there was some indication of reduced wear on the engine.
Technical Paper

Field Experience of DPF Systems Retrofitted to Vehicles with Low Duty Operating Cycles

2004-01-16
2004-28-0013
For many years now, epidemiologists have been highlighting the potential damage to health and the associated cost, caused by diesel particulate emissions. There is still debate concerning the crucial characteristics of these particles, however many authorities have concluded that it is their duty to legislate the reduction of such emissions. The most common approach is to legislate that all new vehicles should meet ever stricter emissions limits. This puts the onus and the cost on the engine manufacturers. The emissions limits in developing countries are inevitably less stringent than those in the developed world, this gives the indigenous manufacturers the opportunity to compete and develop. However, vehicle replacement intervals dictate that the effect of legislation controlling new vehicles takes many years to propagate throughout the existent vehicle fleet.
Technical Paper

Retrofitting of Diesel Particulate Filters - Particulate Matter and Nitrogen Dioxide

2003-05-19
2003-01-1883
A diesel particulate filter (DPF) is a crucial weapon in the fight to control the downsides traditionally associated with diesel engined vehicles. The DPF not only produces the benefits required from an environmental standpoint but also has the consumer benefit of eliminating the visible black smoke associated with diesel engines. Thus DPFs have now become a reality, both for series production vehicles and as a retrofit application. Inevitably there are a number of alternative types of DPF and alternative techniques are used for ensuring they continue to function in an acceptable manner. Due to the complexity of the diesel combustion process and the emissions produced it is only to be expected that a device intended primarily to control one parameter would have some effect on other parameters. This paper looks at some different DPF technologies and how they effect emissions, with the emphasis on particulate emissions and the speciation of oxides of nitrogen.
Technical Paper

A Novel Fuel Borne Catalyst Dosing System for Use with a Diesel Particulate Filter

2003-03-03
2003-01-0382
A novel dosing system for fuel borne catalyst (FBC), used to assist regeneration with a diesel particulate filter (DPF), has been developed. The system was designed for on-board vehicle use to overcome problems encountered with batch dosing systems. Important design features were simplicity, to minimise system cost, and the use of in-line dosing rather than batch dosing linked to tank refuelling. The paper describes the development of the dosing system which continuously doses FBC into the fuel line feeding the engine injection pump. The theoretical considerations behind the concept are explored, together with the realities imposed by fuelling regimes in which a variable proportion of the fuel flowing through the injection pump is passed back to the fuel tank. Two types of system are considered, ie where 1) FBC is added to the fuel in direct proportion to the flow rate of fuel and 2) FBC is added at a constant time-based rate.
Technical Paper

Demonstration of the Benefits of DPF/FBC Systems on London Black Cabs

2003-03-03
2003-01-0375
Future emissions limits are pushing vehicle manufacturers towards the fitting of Diesel Particulate Filters (DPFs) as original equipment. However due to the replacement rate of the vehicle fleet, there is a delay before the full benefit of these measures are fully realised. To overcome this problem, in areas with a particular problem such as heavily congested city centres, retrospective legislation has been, and may be introduced. Legislation mandating the retrofitting of DPFs obviously has an immediate effect on particulate emissions. In some countries including the UK there are also fiscal incentives to fit DPFs. Due to its duty cycle the London taxi or Black Cab is one of the more challenging areas of application for the DPF. Previous work has shown that the use of a fuel borne catalyst (FBC) can extend the operating range of DPF systems providing the possibility of a viable system for such applications.
Technical Paper

A Cost Effective Solution to Reduce Particulate Emissions

2003-01-18
2003-26-0006
Growing concern over the health effects of airborne particles and a desire to reduce the associated cost has resulted in legislation, regulations and other measures, in the industrialised world to severely restrict particulate emissions from diesel-fuelled automotive transport. Developing countries are also introducing initiatives to try and reduce emissions, an example is the legislation in India to replace diesel engines with gas fuelled engines in some major conurbations. Such measures are expensive, both in terms of replacing the engines of the vehicles and of implementing the required infrastructure. There is still also debate over whether such measures reduce the number of ultra-fine particulates. A well-proven alternative is to fit diesel engines with Diesel Particulate Filters (DPFs), either as original equipment or as a retrofit system. Regenerating DPFs has in the past been an obstacle to their widespread application.
Technical Paper

Experience of Fitting London Black Cabs with Fuel Borne Catalyst Assisted Diesel Particulate Filters - Part 1 Regulated Emissions and Regeneration Performance

2002-10-21
2002-01-2784
Forthcoming emissions legislation is driving the passenger car manufacturers towards the fitting of Diesel Particulate Filters (DPFs) as original equipment. However such initiatives are not retrospective and due to the replacement rate of the vehicle fleet, there is a time lag before the full benefit of the new measures are fully realised. To overcome this drawback, in areas with a particular problem such as heavily congested city centres, retrospective legislation has been introduced, for example in Hong Kong and Tokyo. Legislation mandating the retrofitting of DPFs obviously has an immediate effect on particulate emissions. Other authorities are thus investigating the efficacy of such measures. To add to the data base for such assessments Octel is running a demonstration programme using London Black Cabs. Four cars have been fitted with a DPF, an on-board dosing system to meter a fuel borne catalyst (FBC) into the fuel and a data logger to monitor the DPF performance.
Technical Paper

Experience of Fitting London Black Cabs with Fuel Borne Catalyst Assisted Diesel Particulate Filters - Part 2 Non-Regulated Emissions Measurements

2002-10-21
2002-01-2785
Forthcoming emissions legislation is driving the passenger car manufacturers towards the fitting of Diesel Particulate Filters (DPFs) as original equipment. In areas with a particular problem such as heavily congested city centres, retrospective legislation has also been introduced, for example in Hong Kong and Tokyo. Legislation mandating the retrofitting of DPFs obviously has an immediate effect on particulate emissions. Other authorities are thus investigating the efficacy of such measures. However with the increasing use of DPF technology concerns are now being raised over some currently unregulated emissions such as ultra fine particulate and NO2, although total particulate mass and oxides of nitrogen are regulated. To add to the data base for such issues a programme of work was run using London Black Cabs. Four cars were fitted with a DPF, an on-board dosing system to meter a fuel borne catalyst (FBC) into the fuel and a data logger to monitor the DPF performance.
Technical Paper

Preliminary Results from a Six Vehicle, Heavy Duty Truck Trial, Using Additive Regenerated DPFs

2002-03-04
2002-01-0431
Impending legislation will make it almost inevitable that heavy-duty trucks will have to be fitted with some form of particulate removal after-treatment device. The challenge is to provide a system that is not only environmentally acceptable and cost effective but also durable enough to meet the demands of the trucking industry. Diesel particulate filters (DPF), in conjunction with fuel borne catalysts to facilitate regeneration, are now a recognised technology for meeting future passenger car emissions limits. Retrofitting of such systems to older technology vehicles, where specific environmental concerns exist, has demonstrated the possibility of applying this technology to the heavy-duty vehicle sector. Most of these retrofit applications tend to be to vehicles with a relatively low duty cycle. Whereas this type of duty cycle poses the greatest challenge to the successful regeneration of the filters it is not necessarily the most arduous test of the durability of the system.
Technical Paper

Diesel Particulate Filters and Fuel Borne Catalysts as a Viable Solution to Reduced Airborne Particulate

2001-11-01
2001-28-0041
There is mounting worldwide concern over the health effects of airborne ultra-fine particles. Of greatest concern are the risks due to the cancer-inducing properties of these particles and the aggravation of existing respiratory diseases by the ultra-fine (i.e. <2.5 micron) fraction. This disquiet has already resulted in legislation, regulations and other measures, either mandated or proposed, in the industrialised world to severely restrict particulate emissions from diesel-fuelled automotive transport. Emissions of particles from both new and existing vehicles have been addressed. With the rapid growth anticipated in some developing countries they to will need to address this problem. This paper outlines some alternative solutions to the problem, ranging from alternative power sources, alternative fuels, alternative engine technologies and after-treatment strategies. It also outlines what is required to implement these different solutions.
Technical Paper

Fuel Additive Performance Evaluation for Volume Production Application of a Diesel Particulate Filter

2001-03-05
2001-01-1286
Diesel particulate filter (DPF) technology is becoming increasingly established as a practical method for control of particulate emissions from diesel engines. In the year 2000, production vehicles with DPF systems, using metallic fuel additive to assist regeneration, became available in Europe. These early examples of first generation DPF technology are forerunners of more advanced systems likely to be needed by many light-duty vehicles to meet Euro IV emissions legislation scheduled for 2005. Aspects requiring attention in second generation DPF systems are a compromise between regeneration kinetics and ash accumulation. The DPF regeneration event is activated by fuel injection, either late in the combustion cycle (late injection), or after normal combustion (post injection), leading to increased fuel consumption. Therefore for optimum fuel economy, the duration of regeneration and/or the soot ignition temperature must be minimised.
Technical Paper

Combining Fuel Borne Catalyst, Catalytic Wash Coat and Diesel Particulate Filter

2001-03-05
2001-01-0902
In view of increasing concern over diesel particulates and tightening legislation to control their emission, much work has been done to develop diesel particulate filters (DPFs) and systems to allow them to work reliably. Although a filter will effectively trap solid particles, any material in the vapour phase, such as unburned hydrocarbons, may pass through the filter and subsequently condense. The use of a catalytic wash coat, either on the DPF itself or on a separate substrate, has been proposed to oxidise these hydrocarbons and thus reduce the total material emitted. The use of fuel borne catalysts to aid the regeneration of trapped material within the DPF is also well documented. Such catalyst will also catalyse the oxidation of any hydrocarbons bound up within the particulate. The oxidation of such hydrocarbon occurs at a lower temperature than that of carbon itself, thus allowing lower temperature regeneration of the DPF.
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