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Recent developments in diesel fuel injection equipment coupled with moves to using ULSD and biodiesel blends has seen an increase in the number of reports, from both engine manufacturers and fleet operators, regarding fuel system deposit issues. Preliminary work performed to characterise these deposits showed them to be complicated mixtures, predominantly carbon like but also containing other possible carbon precursor materials. This paper describes the application of the combination of hydropyrolysis, gas chromatography and mass spectrometry to the analysis of these deposits. It also discusses the insights that such analysis can bring to the constitution and origin of these deposits.

Initial results are presented for the production of hydrogen from waste lubricating oil using a chemical looping reforming (CLR) process. The development of flexible and sustainable sources of hydrogen will be required to facilitate a "hydrogen economy." The novel CLR process presented in this paper has an advantage over hydrogen production from conventional steam reforming because CLR can use complex, low value, waste oils. Also, because the process is scalable to small and medium size, hydrogen can be produced close to where it is required, minimizing transport costs. Waste lubricating oil typically contains 13-14% weight of hydrogen, which through the steam reforming process could produce a syngas containing around 75 vol% H₂, representing over 40 wt% of the fuel. The waste oil was converted to a hydrogen-rich syngas in a packed bed reactor, using a Ni/ Al₂O₃ catalyst as the oxygen transfer material (OTM).

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 fuel injection equipment (FIE) has always been paramount to the performance of the Diesel engine. Increasingly stringent emissions regulations have dictated that the FIE becomes more precise and sophisticated. The latest generation FIE is therefore less tolerant to deposit formation than its less finely engineered predecessors. However, the latest emissions regulations make it increasingly difficult for engine manufacturers to comply without the use of exhaust aftertreatment. This aftertreatment often relies on catalytic processes that can be impaired by non-CHON (carbon, hydrogen, oxygen and nitrogen) components within the fuel. Fuel producers have therefore also been obliged to make major changes to try and ensure that with the latest technology engines and aftertreatment systems the fuel is still fit for purpose. However, there has recently been a significant increase in the incidence of reported problems due to deposit build-up within vehicle fuel systems.

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. The test vehicle was a modern EURO4 emission compliant SI car equipped with temperature measurement along the exhaust pipe across the catalyst so as to match thermal characteristics to emission profiles. A free flow 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 warm up of the lubricating oil needed 15 minutes. The TWC needed about 200 seconds to reach full conversion efficiency. CO, THC and NOx emissions exceeded the EURO4 exhaust emission legislation. CO2 emissions were well above the type approval value of this vehicle.

A series of chassis dynamometer test trials were conducted to assess the performance of a Fourier Transform Infra Red (FTIR) system developed for on-road vehicle exhaust emissions measurements. Trials used a EURO 1 emission compliant SI passenger car which, alongside the FTIR, was instrumented to allow the routine logging of engine speed, road speed, throttle position, air-fuel ratio, air flow and fuel flow in addition to engine, exhaust and catalyst temperatures. The chassis dynamometer facility incorporated an ‘industry standard’ measurement system comprising MEXA7400 gas analyzer and CVS bag sampling which was the ‘benchmark’ for the evaluation of FTIR legislated gas-phase emissions (CO, NOx, THC and CO2) measurements. Initial steady state measurements demonstrated strong correlations for CO, NOx and THC (R2 of 0.99, 0.97 0.99, respectively) and a good correlation for CO2 (R2 = 0.92).

Traditionally, diesel fuel injection equipment (FIE) has frequently relied on the diesel fuel to lubricate the moving parts. When ultra low sulphur diesel fuel was first introduced into some European markets in the early 1980's it rapidly became apparent that the process of removing the sulphur also removed other components that had bestowed the lubricating properties of the diesel fuel. Diesel fuel pump failures became prevalent. The fuel additive industry responded quickly and diesel fuel lubricity additives were introduced to the market. The fuel, additive and FIE industries expended much time and effort to develop test methods and standards to try and ensure this problem was not repeated. Despite this, there have recently been reports of fuel reaching the end user with lubricating performance below the accepted standards.

A FTIR in-vehicle on-road emission measurement system was installed in a EURO 2 emissions compliant SI car to investigate exhaust emissions under different urban traffic conditions. The real time fuel consumption and vehicle traveling speed was 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 (WP cycle) was located in a quiet area with few traffic interference and the other one (HPL 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. The WP cycle had higher acceleration rate, longer acceleration mode and shorter steady speed driving mode and thus harsher than the HPL cycle.

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. The test vehicle was a EURO 2 emission compliant SI car equipped with real time fuel consumption measurement and temperature measurement along the exhaust pipe across the catalyst allowing the matching of thermal characteristics to emission profiles and monitor fuel consumption. The temperature profile indicated that the light-off of the catalyst took about 150∼200 seconds. The warm up of the lubricating oil and coolant water required a longer time than the catalyst did. The impact of ambient temperatures on lubricating oil and coolant water warm ups was greater than that on the light-off of the catalyst. The heat loss and energy balance were calculated during the whole cycle period. The influence of cold start on fuel consumption was investigated.

With growing concern over greenhouse gases there is increasing emphasis on reducing CO2 emissions. Despite engine efficiency improvements plus increased dieselisation of the fleet, increasing vehicle numbers results in increasing CO2 emissions. To reverse this trend the fuel source must be changed to renewable fuels which are CO2 neutral. A common route towards this goal is to substitute diesel fuel with esterified seed oils, collectively known as Fatty Acid Methyl Esters. However a fundamental change to the fuel chemistry produces new challenges in ensuring compatibility between fuel and engine performance/durability. This paper discusses the global situation and shows how fuel additives can overcome the challenges presented by the use of biodiesel.

An in-vehicle FTIR emission measurement system was used to investigate the exhaust emissions under different real world urban driving conditions. Five different driving cycles were developed based on real world urban driving conditions including urban free flow driving, junction maneuver, congested traffic and moderate speed cruising. The test vehicle was a EURO 2 emission compliant SI car equipped with temperature measurement along the exhaust pipe across the catalyst and real time fuel consumption measurement system. Both regulated and non-regulated emissions were measured and analyzed for different driving cycles. All journeys were started from cold. The engine warm up features and emissions as a function of engine warm up for different driving conditions were investigated.

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).

EURO 1, 2 3 and 4 SI (Spark Ignition) Ford Mondeo passenger cars were compared for their real world cold start emissions using an on-board FTIR (Fourier Transform Infrared) exhaust emission measurement system. The FTIR system can measure up to 65 species including both regulated and non-regulated exhaust pollutants at a rate of 0.5 Hz. The driving parameters such as speed, fuel consumption and air/fuel ratio were logged. The coolant water, lube oil and exhaust temperatures were also recorded. A typical urban driving cycle including a loop and a section of straight road was used for the comparison test as it was similar to the legislative ECE15 urban driving cycle. Exhaust emissions were calculated for the whole journey average and compared to EU legislation. The cold start transient emissions were also investigated as a separate parameter and this was where there was the greatest difference between the four vehicles.

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.

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.

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.

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.