Search Results

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.

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.

Heat Release Rate (HRR) analysis is indispensable in engine research. The HRR of Internal Combustion Engines (ICEs) is most sensitive to gamma (γ). The proposed HRR models in literature were largely based on γ expressed as functions of temperature. However, γ is depended on temperature as well as the excess air ratio (λ). In this work, an improved HRR model based on γ(T, λ) was used to investigate the combustion behaviour of standard diesel, Gas-to-Liquid (GTL) diesel and Hydrotreated Vegetable Oil (HVO) diesel in a 96 kW, multiple fuel injection, Euro V, Direct Injection (DI) engine. The improved HRR model (Leeds HRR model) was validated for the alternative fuels by comparing the fuel masses predicted by the model to the measured fuel masses. The fuel masses predicted by the Leeds HRR model were also compared to the predictions from four HRR models that were based on γ(T).

A Euro 3 1.8-liter diesel vehicle with an oxidation catalyst was used to investigate real-world exhaust emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. 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 multifunctional additive package was added at 800 ppm to control fuel injector deposit formation. Gaseous emissions were monitored using an on-board heated Temet FTIR exhaust emission analyzer, which can measure 52 species at a rate of 0.5 Hz. A Horiba on board emissions measuring system was also used (OBS 1300), which measures the exhaust mass flow rate together with air/fuel ratio.

In order to improve energy supply diversity and reduce carbon dioxide emissions, sustainable bio-fuels are strongly supported by EU and other governments in the world. While the feedstock of biofuels has caused a debate on the issue of sustainability, the used cooking oil (UCO) has become a preferred feedstock for biodiesel manufacturers. However, intensive energy consumption in the trans-esterification process during the UCO biodiesel production has significantly compromised the carbon reduction potentials and increased the cost of the UCO biodiesel. Moreover, the yield of biodiesel is only ∼90% and the remaining ∼10% feedstock is wasted as by-product glycerol. Direct use of UCO in diesel engines is a way to maximize its carbon saving potentials.

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.

An investigation was conducted into particulate PAH emissions from a heavy duty DI diesel engine using; a typical diesel fuel, 100% methyl ester derived from waste cooking oils, and 100% rapeseed oil supplied as fresh cooking oil. This study quantifies the particulate PAH levels emitted at two steady state load conditions, with comparison of the oxidation catalyst efficiency for the main species identified. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser engine, with emission compliance of EURO 2. Particulate samples were also analysed for VOF and carbon content. Both biofuels resulted in reductions in the most abundant particulate PAH species, particularly at the lower load condition. Larger species such as Benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo (k)fluoranthene were detectable for all fuels upstream of the catalyst but were oxidized to near or below detection limits downstream of the catalyst.

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).

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.

Regulated and non-regulated tailpipe exhaust emissions were measured under real world urban driving conditions using a set of in-vehicle FTIR emission measurement system, which is able to measure 65 emission components simultaneously at a rate of 0.5 Hz. A EURO3 emission compliant SI car was used as a probe vehicle. An urban driving cycle was used for the test and four repeated journeys were conducted. The results were compared to EU emissions legislation. The results show that the TWC needed approximately 200 seconds to reach full conversion efficiency. THC and NOx emissions exceeded the EURO 3 exhaust emission legislation. CO2 emissions were well above the type approval value of this type of the vehicle. Greenhouse gases (methane and nitrous oxide) and toxic hydrocarbons such as benzene were predominantly emitted during cold start period from 0 to 200 seconds of the engine start. The results had a reasonable repeatability for most of the emissions.

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.

Pure rape seed oil (RSO), as coded BO100 (BO: Bio-Oil) to distinguish from biodiesel was investigated for a range of intake oxygen levels from 21 to 24%. RSO can have deposit problems in both the fuel injector and piston crown and elevated intake oxygen levels potentially could control these by promoting their oxidation. Increased intake oxygen elevates the peak temperature and this promotes the oxidation of soot and volatile organic compounds. The effect of this on particle mass and on the particle size distribution was investigated using a 6-cylinder 6-liter Perkins Phaser Euro 2 DI diesel engine. The tests were conducted at 47 kW brake power output at 1500 rpm. The particle size distribution was determined from the engine-out exhaust sample using a Dekati microdilution system and nano-SMPS analyzer. The results showed that for air RSO had higher particle mass than diesel and that this mass decreased as the oxygen level was increased.

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.

A cold start Euro 3 1.8 litre Diesel vehicle with an oxidation catalyst was used to investigate real world exhaust emissions over a driving cycle that included urban cold start congested traffic driving conditions. The aim was to identity those aspects of cold start real world driving responsible for higher emissions than in test cycles. Higher real world emissions may contribute to the problem of air quality in urban areas, which has not improved in quality in proportion to the reduced in vehicle exhaust emissions. Diesel, B50 and B100 fuel were compared to determine if real world driving effects were worse for B50 and B100 fuels due to their lower volatility and higher viscosity. The biofuel was WRME, derived from waste rape seed cooking oil. A multifunctional additive package was added to the biofuel at 800ppm to control fuel injector deposit formation. Gaseous emissions were monitored using an on-board heated Temet FTIR exhaust emission analyzer.

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%.