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The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport using a probe vehicle: CO₂, N₂O and CH₄ emissions as a function temperature. It should be highlighted that methane is a greenhouse gas that similarly to carbon dioxide contributes to global warming and climate change. An oxidation catalyst was used to investigate CO₂, N₂O and CH₄ GHG emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. The results were determined under hot start conditions, but in congested traffic the catalyst cooled below its light-off temperature and this resulted in considerable N₂O emissions as the oxidation catalyst temperature was in the N₂O formation band. This showed higher N₂O during hot start than for 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 Euro 2 SI (Spark Ignition) Mondeo was investigated for a fully warmed-up vehicle on a simple urban driving loop. Emissions were monitored using an on-board Horiba OBS (On-Board emission measurement System) 1300. 10 laps of a 0.6 km loop were driven by each driver and this involved 4 junctions per lap. Statistical analysis of 20 drivers was made over 27 repeat junction events for each driver. The statistical analysis of the data showed that for all drivers the CO₂, speed and throttle position were more typical Gaussian in their distribution. NOx and CO on the other hand were lognormal in their distribution. Acceleration, positive and negative throttle jerks (rate of change of throttle angle) were borderline Gaussian. HC (Hydrocarbon) emissions were not Gaussian and there was some evidence for a gamma distribution and for a lognormal distribution. Comparison of mean HC emissions between the drivers was therefore not reliable.

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.

A 10W-50 G4 synthetic lubricating oil (EULUBE oil) was tested on a heavy duty DI diesel engine under two steady state conditions. The exhaust emissions were measured and compared to a 10W-30 CF semi-synthetic lubricating oil. The EULUBE oil contained the friction reduction additive to improve the fuel economy. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, with emission compliance of EURO 2, fitted with an oxidation catalyst. The exhaust samples were taken both upstream and downstream of the catalyst. Gaseous and particulates emissions were measured. Particulate size distribution was measured using ELPI and SMPS. The particulate samples were analysed for VOF, carbon and ash. A MEXA7100 gas analysis system was used for legislated gas analysis such as CO, CO2, NOx and total hydrocarbons. The results showed a significant reduction by synthetic lubricating oil in gaseous hydrocarbon emissions, total particulate mass, particulate carbon and ash.

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).

A precision in-vehicle tail-pipe emission measurement system was installed in a EURO1 emissions compliant SI car and used to investigate the variability in tail-pipe emission generation at an urban traffic junction and uphill/downhill road, and thereby the impact of road topography on emissions. Exhaust gas and skin temperatures were also measured along the exhaust pipe of the instrumented vehicle, so the thermal characteristics and the efficiency of the catalyst could be monitored. Different turning movements (driving events) at the priority T-junction were investigated such as straight, left and right turns with and without stops. The test car was run until hot stable operating conditions were achieved before each test, thereby negating cold start effects.

A rapeseed methyl ester biodiesel RMEB100 was tested on a heavy duty DI diesel engine under steady state conditions. The combustion performance and exhaust emissions were measured and compared to a standard petroleum derived diesel fuel. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, with emission compliance of EURO 2, fitted with an oxidation catalyst. The exhaust samples were taken both upstream and downstream of the catalyst. Particulates were collected and analysed for VOF, carbon and ash. A MEXA7100 gas analysis system was used for legislated gas analysis such as CO, CO2, NOx and total hydrocarbons. A FTIR analysis system was deployed for gaseous hydrocarbon speciation, which is capable of speciating up to 65 species. The results showed a significant reduction in total particulate mass, particulate VOF, CO, THC and aldehydes when using RMEB100.

Condensable and gaseous hydrocarbon emissions and speciation of the hydrocarbons have been investigated using a EURO1 emissions compliant SI (Spark Ignition) car. Exhaust gas samples were simultaneously collected upstream and downstream of the catalyst using a system containing cold ice trap, resin, particulate filter block and Teflon gas sampling bag. GC (Gas Chromatography) was employed to analyze for hydrocarbons and 16 of the more significant hydrocarbons are reported. The test was carried out using both cold start and hot start driving cycles. Results show that the benzene and toluene were major species emitted from the tailpipe under cold start conditions. Methylnaphthalene was a dominated hydrocarbon under hot start conditions. The cold start had significant influence on hydrocarbon emissions. The catalyst out benzene emissions for cold start was thirty times higher than that for hot start.

A precision in-vehicle tail-pipe emission measurement system was installed in a EURO1 emissions compliant SI car and used to investigate the variability in tail-pipe emission generation at an urban traffic junction. Exhaust gas and skin temperatures were also measured along the exhaust pipe of the instrumented vehicle, so the thermal characteristics and the efficiency of the catalyst monitored could be included in the analysis. Different turning movements (driving patterns) at the priority T-junction were investigated such as straight, left and right turns with and without stops. The test car was hot stable running conditions before each test, thereby negating cold start effects. To demonstrate the influence of the junction on tail-pipe emissions and fuel consumption, distance based factors were determined that compared the intersection drive-through measurements with steady speed (state) runs. Fuel consumption was increased at intersections by a factor of 1.3∼5.9.

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.

The influence of ambient temperature on exhaust emissions for an instrumented Euro 1 SI car was determined for urban congested traffic conditions. In UK cities cold-starting vehicles directly into congested traffic conditions is a common occurrence that is not currently taken into account when modeling urban traffic pollution. In-vehicle emission samples were taken directly from the exhaust, upstream and downstream of the catalyst, using the bag sampling technique. The first bag was for the cold start emissions and approximately the first 1.1 km of travel. The following three bags were with a hotter catalyst. The cold start tests were conducted over a year, with ambient temperatures ranging from 2°C to 30°C. The results showed that CO emissions for the cold start were reduced by 70% downstream of the catalyst when the ambient temperature rose from 2°C to 30°C. The corresponding hydrocarbon emissions were reduced by 41% and NOx emissions were increased by 90%.

The influence of ambient temperature on exhaust emissions for an instrumented Euro 1 SI car was determined. A real world test cycle was used, based on an urban drive cycle that was similar to the ECE urban drive cycle. It was based on four laps of a street circuit and an emissions sample bag was taken for each lap. The bag for the first lap was for the cold start emissions. An in-vehicle direct exhaust dual bag sampling technique was used to simultaneously collect exhaust samples upstream and downstream of the three-way catalyst (TWC). The cold start tests were conducted over a year, with ambient temperatures ranging from - 2°C to 32°C. The exhaust system was instrumented with thermocouples so that the catalyst light off temperature could be determined. The results showed that CO emissions for the cold start were reduced by a factor of 8 downstream of catalyst when ambient temperature rose from -2°C to 32°C, the corresponding hydrocarbon emissions were reduced by a factor of 4.

The influence of a diesel oxidation catalyst and a practical exhaust system with two silencers on the storage and release of particulates during cold start real world driving was investigated using a Ford 1.8 litre IDI Mondeo diesel passenger car. Particulates were sampled simultaneously at three points in the exhaust using an on-board gravimetric filter paper method. The test was carried out on two different on-road driving cycles: a simulated ECE 15 cycle to represent free moving low power city driving conditions, and a traffic jam and high speed suburban driving cycle. The results showed that the particulate matter was deposited in the oxidation catalyst during cold start and deposited in the exhaust system downstream of the catalyst throughout the test period. The particulate deposition and release downstream of the catalyst were influenced by the previous operational history of the vehicle.

A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infra red heater. Two bypass filter sizes of 6 and 1 micron were investigated, both filter sizes were effective but the one micron filter had the greatest benefit. This was tested on two nominally identical EURO 2 emissions compliance single decker buses, fitted with Cummins 6 cylinder 8.3 litre turbocharged intercooled engines and coded as Bus 4063 and 4070. These vehicles had emissions characteristics that were significantly different, in spite of their similar age and total mileage. Bus 4063 showed an apparent deterioration on emissions with time while Bus 4070 showed a stabilised trend on emissions with time for their baseline tests without the recycler fitted. Comparison was made with the emissions on the same vehicles and engines with and without the on-line bypass oil recycler. Engine exhaust emissions were measured about every 2000 miles.

A method of cleaning diesel engine lubricating oil on-line was investigated using a bypass fine particulate filter followed by an infra-red heater to remove water vapour and light diesel fractions in the oil. The impact of this oil recycler on the gaseous and particulate emissions was investigated over a 300 hour oil age period. A Ford 1.8 litre IDI passenger car diesel engine was used with engine out emission sampled every 15-20 hours. The tests were carried out at 2500rpm (52% of the maximum speed) and 12.3 kW with 47 Nm load (43% of the maximum load and 29% of the maximum power). The EGR level at this condition was 15%. A stop start test cycle was used with a cold start each time and a typical test period of 2-3 hours. The results showed that the recycler had its greatest influence on emissions for fresh oil when there was a large reduction in particulate emissions due mainly to large reductions in the ash, carbon and unburned lubricating oil fractions.

Two Ford IDI passenger car diesel engines, 1.6 and 1.8 litres, were tested over a 100 hour lube oil ageing period with engine out emission samples every 15 hours. The 1.6 litre engine was tested with 5% EGR and the 1.8 litre engine with 15% EGR. Comparison was also made with previous work using an older Petter AA1 engine. The three engines had different dependencies of particulate emissions on the lube oil age. The 1.6 litre engine increased the particulates from 1 to 2.5 g/kg of fuel, whereas the 1.8 litre engine first decreased the particulate emissions from 3 to 1 g/kg over 50 hours of oil age and then they increased to 2 g/kg at 100 hours. This was similar to the previous work on the Petter AA1 engine, where the emissions first decreased and then increased as the oil aged. For the 1.8 litre engine the lube oil fraction of the VOF was high with fresh oil and decreased with time for the first 50 hours and then remained steady.

Lubricating oil taken from the sump of a direct injection diesel engine has been analysed for the concentration of hydrocarbon contamination over a period of time. The oil was filtered and the sediment SOF analysed together with the filtrate. The results showed that there was an increase in the contamination in the used oil for both the filtrate and sediment hydrocarbon contamination. The carbon number distribution of the filtrate and sediment SOF were different. The filtrate representing contamination of the oil by fuel dilution and the sediment SOF contamination by particulates adsorbed into the oil in the combustion chamber. The highest contribution to the hydrocarbon contamination of the oil was from the filtrate in the early ageing period with an increasing contribution from the SOF of the sediment.

The influence of contamination of lubricating oil on the emissions of total particulate, particulate polycyclic aromatic hydrocarbons (PAH) and unburnt fuel and gaseous emissions have been investigated for a modified Perkins 4.236 D.I. diesel engine. The emissions during fuel firing and motoring in the absence of fuel are compared. The results showed that the exhaust particulate during both firing and motoring were not affected by lubricating oil contamination. Emission of PAH during fuel firing and motoring increase with oil contamination which in turn reflects the build up of PAH with oil age. Some of the particulate PAH are biologically active. The contribution of oil derived PAH increase with age. Comparison of the gaseous emissions during fuel firing and during motoring also showed an increase in UHC with age of lubricating oil.

The solvent organic fraction (SOF) of particulates from the exhaust pipe of a diesel engine, a dilution tunnel and a roadside sample are compared. Three different techniques of SOF analysis are also compared, vacuum oven, solvent extraction and pyroprobe/GC. Gaseous hydrocarbons and the methane contribution were measured in the exhaust pipe throughout the speed and load range of the engine at 185 C and 2 C. The unburnt hydrocarbons decreased with air/fuel ratio for all speeds and there was an overall decrease in emissions with increasing speed. The differential temperature technique showed the maximum mass of hydrocarbon which could condense from the gas phase onto the particulate as the SOF. The method compared well with the actual SOF of the tunnel particulate.

The role of lubricating oil as a sink for polycyclic aromatic compounds (PAC) and alkanes derived from unburnt fuel is described for two different oils used in two different DI diesel engines. The diesel engines used were, an older technology Petter AV1 single cylinder mine pumping engine and a Perkins 4.236 current technology engine. Analysis of the oil was by gas chromatography using simultaneous parallel triple detection, allowing analysis of hydrocarbons and nitrogen and sulphur containing compounds. Analysis of unused lubricating oil showed negligible concentrations of PAC and low molecular weight alkanes (< C20). The oil from each engine was analysed periodically during use and showed a rapid and significant accumulation of hydrocarbons which reached significant concentrations after only 10 hours use. The older technology engine showed a much higher accumulation rate.