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Technical Paper

A Comparison of Tailpipe Gaseous Emissions for RDE and WLTC Using SI Passenger Cars

The drive characteristics and gaseous emissions of legislated Real Driving Emissions (RDE) test data from 8 different spark ignition vehicles were compared to data from corresponding Worldwide harmonized Light vehicles Test Cycle (WLTC) tests. The effect of the official RDE exclusion of cold start and idling on the RDE test, and the effect of the use of the moving averaging window (MAW) analysis technique, were simultaneously investigated. Specific attention was paid to differences in drive characteristics of the three different driving modes and the effect this had on the distance-based CO2, CO and NOx emission factors for each. The average velocity of the RDE tests was marginally greater than the WLTC tests, while the average acceleration was smaller. The CO2 emission appeared on average 4% lower under the RDE tests compared to the WLTC tests, while the CO was 60% lower. The NOx values were 34% lower under the RDE testing, and appeared to be linked to the average acceleration.
Technical Paper

A Cost Effective Solution to Reduce Particulate Emissions

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

A Method for Assessing the Low Temperature Regeneration Performance of Diesel Particulate Filters and Fuel-borne Catalysts

Fuel-borne catalysts are now an accepted means of aiding the self-regeneration of diesel particulate filters (DPFs). In the past it has been possible to assess the effect of these fuel additives by investigating the temperature at which the filter reaches a pressure drop equilibrium. Under these temperature conditions, the particulate matter is oxidised at the same rate as it is being deposited and there is thus no change in pressure drop across the filter. This technique adequately demonstrates the oxidation temperature of the carbon in the presence of the catalyst. However, it is now well known that such fuel additives also influence the low temperature oxidation of particulate bound hydrocarbons. This phenomenon is not detected by the filter equilibrium technique.
Technical Paper

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

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.
Journal Article

A Novel Technique for Investigating the Nature and Origins of Deposits Formed in High Pressure Fuel Injection Equipment

Recent developments in diesel fuel injection equipment coupled with moves to using ULSD and biodiesel blends has seen an increase in the number of reports, from both engine manufacturers and fleet operators, regarding fuel system deposit issues. Preliminary work performed to characterise these deposits showed them to be complicated mixtures, predominantly carbon like but also containing other possible carbon precursor materials. This paper describes the application of the combination of hydropyrolysis, gas chromatography and mass spectrometry to the analysis of these deposits. It also discusses the insights that such analysis can bring to the constitution and origin of these deposits.
Technical Paper

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

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

Analysis of Driving Parameters and Emissions for Real World Urban Driving Cycles using an on-board Measurement Method for a EURO 2 SI car

A FTIR in-vehicle on-road emission measurement system was installed in a EURO 2 emissions compliant SI car to investigate exhaust emissions under different urban traffic conditions. The real time fuel consumption and vehicle traveling speed was measured and logged. The temperatures were measured along the exhaust pipe so as to monitor the thermal characteristics and efficiency of the catalyst. Two real world driving cycles were developed with different traffic conditions. One (WP cycle) was located in a quiet area with few traffic interference and the other one (HPL cycle) was in a busy area with more traffic variations. The test car was pre-warmed before each test to eliminate cold start effect. The driving parameters were analyzed for two real world cycles. The WP cycle had higher acceleration rate, longer acceleration mode and shorter steady speed driving mode and thus harsher than the HPL cycle.
Technical Paper

Analysis of Various Driving Parameters and Emissions for Passenger Cars Driven With and Without Stops at Intersections under Different Test Cycles

Different driving test cycles, the Leeds-West Park (LWP) loop and the Leeds-High Park (LHP) or HPL-A and B (Leeds-Hyde Park Loop-A or B, hereafter referred as HPL-A or B cycle) loop were selected for this urban intersection research and results are presented in this study. Different emissions-compliant petrol passenger cars (EURO 1, 2, 3 and 4) were compared for their real-world emissions. A reasonable distance of steady state speed was needed and for the analysis made in this paper were chosen vehicle speeds at ~20, ~30 and ~40 km/h. Specific spot of periods of driving at the speeds mentioned above were identified, then the starting and ending point was found and the total emissions in g for that period divided by the distance was calculated. A typical urban driving cycle including a loop and a section of straight road was used for the comparison test as it was similar to the legislative ECE15 urban driving cycle.
Technical Paper

Application of a Portable FTIR for Measuring On-road Emissions

The objective of this work was the development of an on-road in-vehicle emissions measurement technique utilizing a relatively new, commercial, portable Fourier Transform Infra-Red (FTIR) Spectrometer capable of identifying and measuring (at approximately 3 second intervals) up to 51 different compounds. The FTIR was installed in a medium class EURO1 spark ignition passenger vehicle in order to measure on-road emissions. The vehicle was also instrumented to allow the logging of engine speed, road speed, global position, throttle position, air-fuel ratio, air flow and fuel flow in addition to engine, exhaust and catalyst temperatures. This instrumentation allowed the calculation of mass-based emissions from the volume-based concentrations measured by the FTIR. To validate the FTIR data, the instrument was used to measure emissions from an engine subjected to a real-world drive cycle using an AC dynamometer.
Technical Paper

Assessment of the Performance of Diesel Particulate Filter Systems with Fuel Additives for Enhanced Regeneration Characteristics

Diesel particulate filter (DPF) are well known as a developing form of exhaust after-treatment for compression ignition engines. Subjected to extensive testing in experimental form, DPFs have yet to achieve widespread application in regular use on production road vehicles, despite their potential for delivering reductions of typically 90% in diesel exhaust particulate emissions. Tests have shown that different additives are effective in enhancing performance in a range of DPF types, and on engines of different configurations. Efforts have been made to correlate performance with engine operating regime, by linking soot particulate condition to the frequency of regeneration. A performance index has been developed to try to predict regeneration characteristics with additive treated fuel. The work has shown that there are engine operating conditions producing soot which is less likely to burn off in the DPF.

Automotive Fuels Reference Book, Third Edition

The first two editions of this title, published by SAE International in 1990 and 1995, have been best-selling definitive references for those needing technical information about automotive fuels. This long-awaited new edition has been thoroughly revised and updated, yet retains the original fundamental fuels information that readers find so useful. This book is written for those with an interest in or a need to understand automotive fuels. Because automotive fuels can no longer be developed in isolation from the engines that will convert the fuel into the power necessary to drive our automobiles, knowledge of automotive fuels will also be essential to those working with automotive engines. Small quantities of fuel additives increasingly play an important role in bridging the gap that often exists between fuel that can easily be produced and fuel that is needed by the ever-more sophisticated automotive engine.
Technical Paper

Characterization of Regulated and Unregulated Cold Start Emissions for Different Real World Urban Driving Cycles Using a SI Passenger Car

An in-vehicle FTIR emission measurement system was used to investigate the exhaust emissions under different real world urban driving conditions. Five different driving cycles were developed based on real world urban driving conditions including urban free flow driving, junction maneuver, congested traffic and moderate speed cruising. The test vehicle was a EURO 2 emission compliant SI car equipped with temperature measurement along the exhaust pipe across the catalyst and real time fuel consumption measurement system. Both regulated and non-regulated emissions were measured and analyzed for different driving cycles. All journeys were started from cold. The engine warm up features and emissions as a function of engine warm up for different driving conditions were investigated.
Technical Paper

Chassis Dynamometer Evaluation of On-board Exhaust Emission Measurement System Performance in SI Car under Transient Operating Conditions

A commercial on-board exhaust emissions measurement system, the Horiba OBS-1300, was evaluated in a series of chassis dynamometer test trails. A EURO 1 (petrol) SI passenger car, operated under normal and rich combustion conditions, and a combination of static and transient sampling provided a wide range of measurement conditions for the evaluation exercise. The chassis dynamometer facility incorporated an ‘industry standard’ measurement system comprising MEXA-7400 gas analyzer and CVS bag sampling system which were used as ‘benchmarks’ for the evaluation of both OBS-1300 component (exhaust flow meter and species analyzer) measurements and ‘daughter’ emission measurements for regulated gas-phase species (CO, CO2, HC and NOx). Trials demonstrated very good to reasonable agreement for exhaust flow and CO, CO2 and HC concentration measurements during static (R2 ≈ 0.97, 0.99, 0.99 and 0.97, respectively) and transient (R2 ≈ 0.88, 0.96, 0.95 and 0.86, respectively) testing.
Technical Paper

Cold Start SI Passenger Car Emissions from Real World Urban Congested Traffic

The tailpipe exhaust emissions were measured under real world urban driving conditions by using a EURO4 emissions compliant SI car equipped with an on-board heated FTIR for speciated gaseous emission measurements, a differential GPS for travel profiles, thermocouples for temperatures, and a MAX fuel meter for transient fuel consumption. Emissions species were measured at 0.5 Hz. The tests were designed to enable cold start to occur into congested traffic, typical of the situation of people living alongside congested roads into a large city. The cold start was monitored through temperature measurements of the TWC front and rear face temperatures and lubricating oil temperatures. The emissions are presented to the end of the cold start, defined when the downstream TWC face temperature is hotter than the front face which occurred at ∼350-400oC. Journeys at various times of the day were conducted to investigate traffic flow impacts on the cold start.
Technical Paper

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

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.
Technical Paper

Comparison of Exhaust Emissions and Particulate Size Distribution for Diesel, Biodiesel and Cooking Oil from a Heavy Duty DI Diesel Engine

Rape oil, as used in fresh cooking oil (FCO), and the methyl ester derived from waste cooking oil (WCOB100) were tested as 100% biofuels (B100) on a heavy duty DI diesel engine under steady state conditions. The exhaust emissions were measured and compared to those for conventional low sulphur (<50ppm) diesel fuel. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Euro2 Phaser Engine, fitted with an oxidation catalyst. The engine out gaseous emissions results for WCOB100 showed a large decrease in CO and HC emissions, but a small increase in NOx emissions compared to diesel. However, for FCO the CO and HC increased relative to WCOB100 and CO was higher than for diesel, indicating deterioration in fuel/air mixing. The particulate matter (PM) emissions for WCOB100 were similar to those for diesel at the 23kw condition, but greatly reduced at 47kw. The FCO produced higher engine out PM at both power conditions due to a higher volatile organic fraction (VOF).
Journal Article

Comparison of Gaseous Emissions for B100 and Diesel Fuels for Real World Urban and Extra Urban Driving

A Euro 3 1.8-liter diesel vehicle with an oxidation catalyst was used to investigate real-world exhaust emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. Diesel fuel and B100 were compared. The B100 fuel was Fatty Acid Methyl Ester (FAME), derived from waste cooking oil, which was mainly RME. A multifunctional additive package was added at 800 ppm to control fuel injector deposit formation. Gaseous emissions were monitored using an on-board heated Temet FTIR exhaust emission analyzer, which can measure 52 species at a rate of 0.5 Hz. A Horiba on board emissions measuring system was also used (OBS 1300), which measures the exhaust mass flow rate together with air/fuel ratio.
Technical Paper

Comparison of Particulate PAH Emissions for Diesel, Biodiesel and Cooking Oil using a Heavy Duty DI Diesel Engine

An investigation was conducted into particulate PAH emissions from a heavy duty DI diesel engine using; a typical diesel fuel, 100% methyl ester derived from waste cooking oils, and 100% rapeseed oil supplied as fresh cooking oil. This study quantifies the particulate PAH levels emitted at two steady state load conditions, with comparison of the oxidation catalyst efficiency for the main species identified. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser engine, with emission compliance of EURO 2. Particulate samples were also analysed for VOF and carbon content. Both biofuels resulted in reductions in the most abundant particulate PAH species, particularly at the lower load condition. Larger species such as Benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo (k)fluoranthene were detectable for all fuels upstream of the catalyst but were oxidized to near or below detection limits downstream of the catalyst.
Technical Paper

Comparison of Real World Emissions in Urban Driving for Euro 1-4 Vehicles Using a PEMS

An on-board emission measurement system (PEMS), the Horiba OBS 1300, was installed in Euro 1-4 SI cars of the same model to investigate the impact of vehicle technology on exhaust emissions, under urban driving conditions with a fully warmed-up catalyst. A typical urban driving loop cycle was used with no traffic loading so that driver behavior without the influence of other traffic could be investigated. The results showed that under real world driving conditions the NOx emissions exceeded the legislated values and only at cruise was the NOx emissions below the legislated value. The higher NOx emissions during real-world driving have implications for higher urban Ozone formation. With the exception of the old EURO1 vehicle, HC and CO emissions were under control for all the vehicles, as these are dominated by cold start issues, which were not included in this investigation.
Technical Paper

Comparisons of the Exhaust Emissions for Different Generations of SI Cars under Real World Urban Driving Conditions

EURO 1, 2 3 and 4 SI (Spark Ignition) Ford Mondeo passenger cars were compared for their real world cold start emissions using an on-board FTIR (Fourier Transform Infrared) exhaust emission measurement system. The FTIR system can measure up to 65 species including both regulated and non-regulated exhaust pollutants at a rate of 0.5 Hz. The driving parameters such as speed, fuel consumption and air/fuel ratio were logged. The coolant water, lube oil and exhaust temperatures were also recorded. A typical urban driving cycle including a loop and a section of straight road was used for the comparison test as it was similar to the legislative ECE15 urban driving cycle. Exhaust emissions were calculated for the whole journey average and compared to EU legislation. The cold start transient emissions were also investigated as a separate parameter and this was where there was the greatest difference between the four vehicles.