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Findings from an intermediate ambient temperature vehicle driveability study for isobutanol gasoline blends are reported. The pattern for the study was Coordinating Research Council Project CM-138-02, which investigated the effects of ethanol on cold-start/warm-up performance and Driveability Index. Objectives of the present study were: (a) to evaluate the efficacy of the current ASTM Driveability Index (DI) in predicting cold-start and warm-up driveability performance for isobutanol gasolines and (b) if required, identify modifications to the DI definition and specification limits for isobutanol blends. The test fuel matrix included fifteen fuels with nominal vapor pressures of 55 kPa (8 psi) at DI levels of 1150, 1200, 1250, and 1300 and isobutanol concentrations of 0, 16, and 24 volume percent. Twelve port- and direct-fuel-injected vehicles, which included US Tier 2 passenger cars and light-duty trucks from model years 2005 through 2008, were used to evaluate the test fuels.

A number of studies have been carried out examining the impact of biodiesel blend ratio on vehicle performance and emissions, however there is relatively little data available on the interaction between blend ratio and reduced ambient temperatures over the New European Drive Cycle (NEDC). This study examines the effects of increasing the blend ratio of Rapeseed Methyl Ester (RME) on the NEDC fuel consumption and tailpipe emissions of a vehicle equipped with a 2.0 litre common rail diesel engine, tested on a chassis dynamometer at ambient temperatures of 25, 10 & −5°C. This study found that under low temperature ambient conditions increasing blend ratios had a significant detrimental effect on vehicle particulate emissions reversing the benefits observed at higher ambient temperatures. Blend ratio was found to have minimal impact on hydrocarbon emissions regardless of ambient temperature while carbon monoxide and NOx emissions were found to increase by up to 20% and 5.5% respectively.

Particulate emission control from diesel engines is one of the major concerns in the urban areas in California. Recently, regulations have been proposed for stringent PM emission requirements from both existing and new diesel engines. As a result, particulate emission control from urban diesel engines using advanced particulate filter technology is being evaluated at several locations in California. Although ceramic based particle filters are well known for high PM reductions, the lack of effective and durable regeneration system has limited their applications. The continuously regenerated diesel particulate filter (CRDPF) technology discussed in this presentation, solves this problem by catalytically oxidizing NO present in the diesel exhaust to NO2 which is utilized to continuously combust the engine soot under the typical diesel engine operating condition.

The current test programmes have measured emissions from a heavy-duty bus engine installed on a test bench and also on a chassis dynamometer whilst running on a Diesel/water emulsion fuel. Testing was carried out over both steady state and transient test cycles. Emissions were also measured on the test bed from the engine fitted with both a Diesel particulate filter and an oxidation catalyst. Alongside the measurement of the regulated emissions, particle number distributions (by size) and total particle counts were also measured. Size selected particle counts were made over the transient tests and are compared between engine test and chassis dynamometer. This paper demonstrates the influence of the emulsion on the particle size distribution, the effects of after-treatment and lubricant on the particle size emissions of an engine running on an emulsion and also the influence of sampling conditions on the measurements recorded.

Following concern about the association between adverse health effects and ambient particulate concentrations, there are now an increasing number of heavy-duty Diesel engines fitted with catalysed particulate filters. These filters virtually eliminate carbon particle emissions but there is some evidence suggesting a potential to form a cloud of secondary nucleation particles post trap. This event occurs at high temperature operating conditions and is produced mainly from the increased sulphate production over the catalyst. This paper investigates the measurement of particle emissions from a heavy-duty engine operating over the European legislated cycle, both with and without a filter fitted and investigates how emissions are affected by the use of a sulphur-free Diesel fuel. The work also demonstrates a contribution to the measured nucleation particles from material desorbed not only from the trap, but also from the exhaust system.

As part of a cooperative development program, six diesel fuels (a reference and five blends containing oxygenates) were evaluated under four steady-state conditions using a prototype 1.26-L 3-cylinder four-valve common-rail DI diesel engine. All of the fuels contained low sulfur (mostly < 5 ppm by mass), and they were chosen to determine the impacts of oxygenate volatility, concentration, and chemical type (paraffinic or aromatic) on exhaust emissions - with particular emphasis on particulate emissions. In addition to HC, CO, NOx and PM emissions measurements, emissions of the volatile portion of the PM and particle size were determined. Relative to the very low sulfur reference fuel, the oxygenated fuels reduced PM and NOx under some operating conditions, but produced little effect on either HC or CO emissions. Aliphatic oxygenates at 6 wt. percent oxygen in the reference fuel reduced simulated FTP PM emissions by 15 - 27 %.

A recently completed program was developed to evaluate ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different truck and bus fleets operating in Southern California. The primary test fuels, ECD and ECD-1, are produced by ARCO, a BP company, and have less than 15 ppm sulfur content. A test fleet comprised of heavy-duty trucks and buses were retrofitted with one of two types of catalyzed diesel particle filters, and operated for one year. As part of this program, a chemical characterization study was performed in the spring of 2001 to compare the exhaust emissions using the test fuels with and without aftertreatment. A detailed speciation of volatile organic hydrocarbons (VOC), polycyclic aromatic hydrocarbons (PAH), nitro-PAH, carbonyls, polychlorodibenzo-p-dioxins (PCDD) and polychlorodibenzo-p-furans (PCDF), inorganic ions, elements, PM10, and PM2.5 in diesel exhaust was performed for a select set of vehicles.

A study was performed in the spring of 2001 to chemically characterize exhaust emissions from trucks and buses fueled by various test fuels and operated with and without diesel particle filters. This study was part of a multi-year technology validation program designed to evaluate the emissions impact of ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different heavy-duty vehicle fleets operating in Southern California. The overall study of exhaust chemical composition included organic compounds, inorganic ions, individual elements, and particulate matter in various size-cuts. Detailed descriptions of the overall technology validation program and chemical speciation methodology have been provided in previous SAE publications (2002-01-0432 and 2002-01-0433).

Rising fuel prices and global concern over climate change have resulted in the need to deliver vehicles with improved fuel efficiency. The aim is to achieve this without compromising vehicle performance, durability or cost. Passenger car manufacturers worldwide are looking at various ways to optimize fuel economy performance. One option is for a vehicle OEM to re-design engine componentry in an effort to reduce engine friction and thereby reduce tailpipe emissions. There is also an increased focus on the crankcase lubricant as a potential tool to improve engine efficiency. This has led to a close collaborative working model between equipment manufacturers and engine oil marketers to create state of the art fluids capable of delivering higher fuel economy benefits without compromising engine durability. This paper describes a structured approach to the design of an advanced engine oil for a diesel passenger car.

The impact of lubricant sulphur and phosphorus levels on the formation of nucleation mode particles was explored in a light duty diesel vehicle operating over the New European Drive Cycle (NEDC). All measurements were undertaken using a Scanning Mobility Particle Sizer (SMPS), sampling from a conventional Constant Volume Sampler (CVS) system. Rigorous sampling system and vehicle conditioning procedures were applied to eliminate oil carry-over and nanoparticle artifact formation. An initial vehicle selection process was undertaken on vehicles representing three fuel injection strategies, namely; distributor pump, common rail and unit injector. The vehicles met Euro III specifications and were all equipped with oxidation catalysts. Idle and low load stability were key requirements, since these conditions are the most significant in terms of their propensity to generate nucleation mode particles.

A 1.3-L direct injection diesel engine was used in steady-state testing to determine the emissions performance of a matrix of ultra-low sulfur diesel fuels encompassing two types of sulfur removal and the use of fuel oxygenates. As expected, exhaust gas recirculation was the most effective technique for NOx reduction. With regard to fuel effects, an oxygenated diesel fuel produced with a conventional sulfur removal process reduced particulate emissions substantially, and these particulate reductions could be converted into NOx reductions by using higher levels of exhaust gas recirculation. On a simulated FTP, this oxygenated fuel simultaneously decreased NOx emissions by 30% and total particulate emissions by 50% compared to a baseline fuel.

A previous paper reported (SAE Paper 2002-01-2884) that it was possible to decrease mode-weighted NOx emissions compared to the OEM calibration with corresponding increases in particulate matter (PM) emissions. These PM emission increases were partially overcome with the use of oxygenated diesel fuel additives. We wanted to know if compounds of toxicological concern were emitted more or less using oxygenated diesel fuel additives that were used in conjunction with a modified engine operating strategy to lower engine-out NOx emissions. Emissions of toxicologically relevant compounds from fuels containing triproplyene glycol monomethyl ether and dibutyl maleate were the same or lower compared to a low sulfur fuel (15 ppm sulfur) even under engine operating conditions designed to lower engine-out NOx emissions.

A multi-year technology validation program was completed in 2001 to evaluate ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different diesel fleets operating in Southern California. The fuels used throughout the validation program were diesel fuels with less than 15-ppm sulfur content. Trucks and buses were retrofitted with two types of passive DPFs. Two rounds of emissions testing were performed to determine if there was any degradation in the emissions reduction. The results demonstrated robust emissions performance for each of the DPF technologies over a one-year period. Detailed descriptions of the overall program and results have been described in previous SAE publications [2, 3, 4, 5]. In 2002, a third round of emission testing was performed by NREL on a small subset of vehicles in the Ralphs Grocery Truck fleet that demonstrated continued robust emissions performance after two years of operation and over 220,000 miles.