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This work investigates the effect of a multifunctional diesel fuel additive package used with RapeSeed Oil (RSO) as a fuel in a DI heavy duty diesel engine. The effects on fuel injectors’ cleanliness were assessed. The aim was to maintain combustion performance and preventing the deterioration of exhaust emissions associated with injector deposit build up. Two scenarios were investigated: the effect of deposit clean-up by a high dose of the additive package; and the effect of deposit prevention using a moderate dose of the additive package. Engine combustion performance and emissions were compared for each case against use of RSO without any additive. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, fitted with an oxidation catalyst and meeting the Euro II emissions limits. The tests were conducted under steady state conditions of 23kW and 47kW power output at an engine speed of 1500 rpm.

A FTIR in-vehicle on-road emission measurement system was installed in a EURO2 emissions compliant SI (Spark Ignition) car to investigate exhaust Volatile Organic Compounds (VOC) emissions and Ozone Formation Potential (OFP) under different urban traffic conditions. The real time fuel consumption and vehicle traveling speed were 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 (West Park Loop cycle) was located in a quiet area with few traffic interference and the other one (Hyde Park Loop 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.

Current developments in fuels and emissions regulations are resulting in an increasingly severe operating environment for diesel fuel injection systems. The formation of deposits within the holes or on the outside of the injector nozzle can affect the overall system performance. The rate of deposit formation is affected by a number of parameters, including operating conditions and fuel composition. For the work reported here an accelerated test procedure was developed to evaluate the relative importance of some of these parameters in a high pressure common rail fuel injection system. The resulting methodology produced measurable deposits in a custom-made injector nozzle on a single-cylinder engine. The results indicate that fuels containing 30%v/v and 100% Fatty Acid Methyl Ester (FAME) that does not meet EN 14214 produced more deposit than an EN590 petroleum diesel fuel.

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.

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).

Exhaust emissions legislation for diesel engines generally limits only the mass of emitted particulate matter. This limitation reflects the concerns and measurement technology at the time the legislation was drafted. However, evolving diesel particulate filter (DPF) systems offer the potential for reductions in the mass and more importantly, the number of particles emitted from diesel exhausts. Particulate filters require frequent cleaning or regeneration of accumulated soot, if the engine is to continue to operate satisfactorily. Exothermic reactions during regeneration can lead to severe thermal gradients in the filter system resulting in damage. Fuel additives have been evaluated to show significant reductions in light off temperature which allow frequent small regeneration events to occur, under mild operating conditions.

This work investigates the heating of unprocessed rapeseed oil as a means to improve fuel delivery by reducing the fuel viscosity, and to assess the effects on combustion performance. The results show that a simple low power heater with thermal insulation around the fuel line and pump can effectively raise the operational fuel temperature at delivery to the pump. The results show that even with a moderate temperature increase, the fuel flow limitations with rapeseed oil are reduced and the legislated gaseous emissions are reduced at steady state conditions. As one of the main reasons for the conversion of straight oils to the methyl ester, ie biodiesel, is to reduce the viscosity, this work shows that heating the oil can have a similar effect. An emissions benefit is observed with biodiesel compared to rapeseed oil but this is not large. There is also a significant greenhouse gas and cost benefit associated with straight vegetable oils.

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.

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.

Current developments in fuels and emissions regulations are resulting in increasingly severe operating environment for the injection system. Formation of deposits within the holes of the injector nozzle or on the outside of the injector tip may have an adverse effect on overall system performance. This paper provides a critical review of the current understanding of the main factors affecting deposit formation. Two main types of engine test cycles, which attempt to simulate field conditions, are described in the literature. The first type involves cycling between high and low load. The second involves steady state operation at constant speed either at medium or high load. A number of influences on the creation of deposits are identified. This includes fouling through thermal condensation and cracking reactions at nozzle temperatures of around 300°C. Also the design of the injector holes is an influence, because it can influence cavitation.

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.

A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infrared heater, to remove water and light diesel fractions in the oil. The impact of this oil recycler with 1 micron fine bypass filter on oil quality was investigated over a 72 hour oil age. Comparisons tests were undertaken without and with the recycler on a Euro 2 Perkins Phaser 180Ti 6 cylinder 6 litre turbo-charged inter-cooled DI diesel engine. The tests were carried out at 2000rpm and 100kW with 473 Nm load. A stop start test cycle was used with a cold start each time and a typical test period of 2 hours. The results showed that the oil quality in this low emission engine test was extremely good. The on line recycler achieved improvements in the oil quality. With the recycler, the carbon accumulation rate in the oil was reduced by 78%. The carbon removal rate by the recycler was 0.40 g/hr. The wear metals in the oil were significantly reduced.

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 1 emissions compliance refuse trucks, fitted with Perkins Phazer 210Ti 6 litre turbocharged intercooled engines and coded as RT320 and RT321. These vehicles had emissions characteristics that were significantly different, in spite of their similar age and total mileage. RT321 showed an apparent heavier black smoke than RT320. 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 400 miles. Both vehicles started the test with an oil drain and fresh lubricating oil.

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 1 emissions compliance refuse trucks, fitted with Perkins Phazer 210Ti 6 litre turbocharged intercooled engines and coded as RT320 and RT321. These vehicles had lubricating oil deterioration and emissions characteristics that were significantly different, in spite of their similar age and total mileage. RT321 showed an apparent heavier black smoke than RT320. Comparison was made with the oil quality and fuel and lubricating oil consumption on the same vehicles and engines with and without the on-line bypass oil recycler. Engine oils were sampled and analysed about every 400 miles. Both vehicles started the test with an oil drain and fresh lubricating oil.

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.

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.

A method of cleaning lubricating oil on line was investigated using a one micron bypass particulate filter followed by an infra-red heater, to remove water, dissolved gases and light diesel fractions in the oil. The impact of this oil recycler on oil quality was studied using synthetic oil in an on-road bus test. The bus was of Euro-1 emissions standard and equipped with a Cummins 6 cylinder 8.3 litre turbo-charged inter-cooled DI engine. Comparisons tests were undertaken with and without the oil recycler for about 28,000 miles. Oil samples were analysed about every 2000 miles. The results showed that the on line oil recycler achieved significant improvements in the oil quality. With the recycler, the TBN depletion rate was reduced by 52%, the TAN increase rate was reduced by 27% and the carbon accumulation rate in the oil was reduced by 42%. The fuel dilution was reduced by the recycler.

A method of cleaning lubricating oil on line was investigated using a fine 1 micron bypass particulate filter, followed by an infra-red heater to remove water and light diesel fractions in the oil. A Ford 1.8 litre IDI diesel passenger car was investigated under real world driving conditions. Comparison was made with the oil quality without the recycler. All the tests were carried out on the same vehicle over 7000 miles with and without the recycler. The results showed that the on line oil recycler cleaning system reduced the rate of reduction of TBN and the rate of increase of TAN by 54% and 50% respectively. The reduction in the rate of carbon accumulation in the oil was 42%. There was also a reduction in fuel dilution. All the wear metals in the oil were greatly reduced by the recycler, the iron was reduced by 76%, the lead was reduced by 85% and the aluminum was totally removed.