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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.

Lubricating oil takes all of the NEDC test cycle time to reach 90°C. Hence, this gives high friction losses throughout the test cycle, which leads to a significant increase in the fuel consumption. In real world driving, particularly in congested traffic, it is shown that lube oil warm-up is even slower than in the NEDC. Euro 1, 2 and 4 Ford Mondeo water and oil warm up rates in real world urban driving were determined and shown to be comparable with the results of Kunze et al. (2) for a BMW on the NEDC. This paper explores the use of forced convective heat exchange between the cooling water and the lube oil during the warm-up period. A technique of a step warm-up of the engine at 32 Nm at 2000 rpm (35% of peak power) was used and the engine lube oil and water temperature monitored. It was shown that the heat exchanger results in an increase in lube oil temperature by 4°C, which increased to 10°C if enhanced heat transfer to the water was used from an exhaust port heat exchanger.

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.

New EU environmental law requires 31 ozone precursor VOCs (Volatile Organic Compounds) to be measured for urban air quality control. In this study, 23 out of the 31 ozone precursor VOCs were measured at a rate of 0.5 HZ by an in-vehicle FTIR (Fourier Transform InfraRed) emission measurement system along with 15 other VOCs. The vehicle used was a EURO2 emission compliant SI car. The test vehicle was driven under real world urban driving conditions on the same route by the same driver on different days at different ambient temperatures. All the journeys were started from cold. The VOC emissions and OFP (Ozone Formation Potential) as a function of engine warm up and ambient temperatures during cold start were investigated. The exhaust temperatures were measured along with the exhaust emissions. The temperature and duration of light off of the catalyst for VOCs was monitored.

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.

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.

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.

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.

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.

A method of cleaning lubricating oil on line was investigated using a fine 1μm bypass particulate filter followed by a 150°C infra-red heater, to remove water and light diesel fractions in the oil. The impact of this oil recycler on diesel particulate and gaseous emissions was investigated over a 72 hour oil age. Comparison 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 fitted with an oxidation catalyst. Emissions were sampled from both upstream and downstream of the catalyst about every 10 hours. 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 this engine had extremely low particulate emissions and was well inside the Euro 2 emissions limits.

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.

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.

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.