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Small diesel engines are a common primer for micro and mini-grid systems, which can supply affordable electricity to rural and remote areas, especially in developing countries. These diesel generators have no exhaust after-treatment system thus exhaust emissions are high. This paper investigates the potential of introducing simulated synthetic gas (syngas) to diesel in a small diesel engine to explore the opportunities of widening fuel choices and reducing emissions using a 5.7kW single cylinder direct injection diesel generator engine. Three different simulated syngas blends (with varying hydrogen content) were prepared to represent the typical syngas compositions produced from downdraft gasification and were injected into the air inlet. In-cylinder pressure, ignition delay, premixed combustion, combustion stability, specific energy consumption (SEC), and gaseous and particle emissions were measured at various power settings and mixing ratios.

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.

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 of cold start and ambient temperatures. A real-world driving cycle has been developed at Leeds and referred as LU-BS, which has an urban free flow driving pattern. The test vehicle was driven on the same route by the same driver on different days with different ambient temperatures. All the journeys were started from cold. An in-vehicle FTIR emission measurement system was installed on a EURO2 emission compliance SI car for emissions measurement at a rate of 0.5 Hz. This emission measurement system was calibrated on a standard CVS measurement system and showed an excellent agreement on the CO₂ measurement with the CVS results. The N₂O and CH₄ were calibrated by calibration gas bottles.

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.

Aldehydes and other Volatile Organic compounds (VOC) are assessed under cold start and steady state conditions using a Perkins Phaser 6 litre diesel engine. A comparison is made between petroleum diesel fuel (PD), 100% biodiesel (WME) and 100% rapeseed oil (RSO). A Temet FTIR was used to determine aldehydes including formaldehyde, acetaldehyde and acrolein. The diesel engine was cold started at room temperature using a step start up procedure that kept the power output constant at two steady state conditions: 23kW and 47kW. Very little difference was observed between petroleum diesel and biodiesel aldehyde emissions at either steady state conditions or during cold start. There was, however, an increase in aldehydes at steady state for rapeseed oil, particularly at low load, but only for from ∼10ppm to 25 ppm for formaldehyde (i.e. 0.12g/kWh to 0.37g/kWh). During cold start conditions, the emissions were significantly higher for rapeseed oil than for petroleum diesel.

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.

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.

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.

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).

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.

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.

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.

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 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 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.