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Mass weighted size distributions of particulate emissions as a function of oil age were investigated using a set of Anderson Impactors on an IDI passenger car engine test. This engine was fitted with an on-line bypass lubricating oil recycler aiming to extend the oil life, reduce fuel consumption and exhaust emissions. A stop start test cycle was used with a cold start each time and a typical cycle period of 2∼3 hours. The whole test was carried out for nearly 500 hours. The first 310 hours of testing were with the oil recycler fitted and thereafter the test continued with the oil recycler disconnected. The results show that 60∼80% of mass particulates were smaller than 1.1 μm in aerodynamic diameter with the oil recycler fitted and this percentage was reduced to 40∼60% after disconnection of the oil recycler. The changes in size distribution with oil age mainly happened in the size ranges of 1.1∼0.65 μm, 0.65∼0.43 μm and <0.43 μm.

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 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 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 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.

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 objective was to investigate PAH emissions in diesel particulates using two diesel fuels with different PAH content. Class A2 diesel from two different refinery sources were analysed for PAH and there were significant difference in the concentration of the 3 and 4 ring PAH of importance in particulate PAH emissions. One fuel had at least 20 times the benzo[a]pyrene (BaP) of the other. A mass balance between the fuel PAH input to the engine and the particulate PAH emissions was carried out. A similar mass balance was also carried out between the equivalent boiling point n-alkane fuel and particulate SOF, which determined how that distillation fraction of the fuel behaved in the engine. One of the fuels had a higher survivability of high MW n-alkanes and this was also reflected in the PAH emissions. The fuel with high BaP had BaP emissions entirely consistent with an unburned fuel source.

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.

The role of lubricating oil in total particulate emmissions and in terms of polycyclic aromatic compounds (PAC) associated with the solvent organic fraction (SOF) of the particulate are investigated. Analysis of unused lubricating oil shows negligible concentrations of PAC. Used lubricating oil from a modified Perkins 4.236 Diesel engine, showed significant concentrations of PAC had accumulated in the oil in the form of PAC from unburnt fuel. Analysis of the oil was by gas chromatography using simultaneous parallel triple detection, allowing analysis of polycyclic aromatic hydrocarbons (PAH), nitrogen containing PAH (PANH) and sulphur containing PAH (PASH). Motoring the engine in the absence of fuel enabled the contribution of lubricating oil to the exhaust particulate and particulate PAC emission to be determined.

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.

The contribution of spark ignition engine particulate emissions to total particulate emissions and the published data on SI engine emission levels are reviewed. There is a wide spread of published data and the worst SI engines would exceed the future diesel particulate emissions regulations. However, most modern SI engines with a catalyst will easily meet the future diesel particulate emissions regulations, although their particulates emissions are a significant fraction of these regulations. Steady state lambda 1 results are presented for a Ford Zetec SI engine at conditions representative of the urban driving cycle at 5 and 10kW power output and also at WOT. The impact of a cold start and EGR at the two low power conditions was also investigated. The particulate emissions for petrol were of the order of 5% of the future (2005) diesel emissions regulations and were approximately 20 mg/kg fuel (about 2 mg/mile or 1.3 mg/km).

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.