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The Particulate Matter Index (PMI) is a tool that provides an indication of a fuel’s tendency to produce Particulate Matter (PM) emissions. Currently, the index is being used by various fuel laboratories and the Automotive OEMs as a tool to understand the gasoline fuel’s impact on both PM from engine hardware and vehicle-out emissions. In addition, a newer index that could be used to give an indication of the PM tendency of the gasoline range fuels, called the Particulate Evaluation Index (PEI), is shown to have a good correlation to PMI. The data used in those indices are collected from chemical analytical methods. This paper will compare gas chromatography (GC) methods used by three laboratories and discuss how the different techniques may affect the PMI and PEI calculation.

Reliable driveaway from frozen condition is one of the challenging design and control problem for fuel cell applications. Different approaches for warmup from frozen conditions have been developed by OEMs, e.g. low voltage inefficient operation, or use of coolant heaters. However, most methods result in water generation which risk icing and blocking the valves and rendering them nonfunctional till they thaw. One such valve is the anode drain valve which is needed to remove water that crosses over across the membrane to anode side. This work discusses characterization of dynamics of water crossover to anode balance of plant via step response experiments on full scale systems, and development of an online estimator to detect onset of anode water crossover via this online observer. In addition, detection via voltage dip-based feedback is also presented.

The diesel particulate filters (DPF) are considered the most robust technologies for particle emission reduction both in terms of mass and number. On the other hand, the increase of the backpressure in the exhaust system due to the accumulation of the particles in the filter walls leads to an increase of the engine fuel consumption and engine power reduction. To limit the filter loading, and the backpressure, a periodical regeneration is needed. Because of the growing interest about particle emission both in terms of mass, number and size, it appears important to monitor the evolution of the particle mass and number concentrations and size distribution during the regeneration of the DPFs. For this matter, in the presented work the regeneration of a catalyzed filter was fully analyzed. Particular attention was dedicated to the dynamic evolution both of the thermodynamic parameters and particle emissions.

More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion engines. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number-based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs). One method is a thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample-handling methods have been implemented in an engine test cell with a spark-ignited direct injection (SIDI) engine. The engine was designed for stoichiometric, homogeneous combustion.

In the previous research1), the authors discovered that the sudden pressure increase phenomenon in diesel particulate filter (DPF) was a result of soot collapse inside DPF channels. The proposed hypothesis for soot collapse was a combination of factors such as passive regeneration, high humidity, extended soak period, high soot loading and high exhaust flow rate. The passive regeneration due to in-situ NO2 and high humidity caused the straw like soot deposited inside DPF channels to take a concave shape making the collapse easier during high vehicle acceleration. It was shown that even if one of these factor was missing, the undesirable soot collapse and subsequent back pressure increase did not occur. Currently, one of the very popular NOx reduction technologies is the Selective Catalytic Reduction (SCR) on Filter which does not have any platinum group metal (PGM) in the washcoat.

The impact of gasoline composition on vehicle particulate emissions response has been widely investigated and documented. Correlation equations between fuel composition and particulate emissions have also been documented, e.g. Particulate Matter Index (PMI) and Particulate Evaluation Index (PEI). Vehicle PM/PN emissions correlate very well with these indices. In a previous paper, global assessment with PEI on fuel sooting tendency was presented [1]. This paper will continue the previous theme by the authors, and cover China gasoline in more detail. With air pollution an increasing concern, along with more stringent emission requirements in China, both OEMs and oil industries are facing new challenges. Emissions controls require a systematic approach on both fuels and vehicles. Chinese production vehicle particulate emissions for a range of PEI fuels are also presented.

The objective of this research is a detailed investigation of particulate sizing and number count from a spark-ignited, direct-injection (SIDI) engine at different operating conditions. The engine is a 549 [cc] single-cylinder, four-valve engine with a flat-top piston, fueled by Tier II EEE. A baseline engine operating condition, with a low number of particulates, was established and repeatability at this condition was ascertained. This baseline condition is specified as 2000 rpm, 320 kPa IMEP, 280 [°bTDC] end of injection (EOI), and 25 [°bTDC] ignition timing. The particle size distributions were recorded for particle sizes between 7 and 289 [nm]. The baseline particle size distribution was relatively flat, around 1E6 [dN/dlogDp], for particle diameters between 7 and 100 [nm], before dropping off to decreasing numbers at larger diameters. Distributions resulting from a matrix of different engine conditions were recorded.

With increasing use of ethanol in automotive fuel in recent years, which can be made from renewable feedstocks, the chemical composition of gasoline is changed. The compositional change results in many changes in fuel properties. One key property is the octane rating of gasoline. Market data has shown the shifts of octane rating (antiknock index or AKI) upward due to more penetration of E10 gasoline in the US market. However, the increase in research octane is more pronounced as compared to motor octane, therefore the increase in octane sensitivity in gasoline. Refineries have used the change in octane due to ethanol contribution by sending so called sub-grade gasoline to terminals expecting the final blend after mixing with ethanol to meet the market requirement in octane. Thus the octane rating of the final blend will largely depend on the sub-grade gasoline composition and ethanol.

Gasoline Direct Injection (GDI) has become the preferred technology for spark-ignition engines resulting in greater specific power output and lower fuel consumption, and consequently reduction in CO2 emission. However, GDI engines face a substantial challenge in meeting new and future emission limits, especially the stringent particle number (PN) emissions recently introduced in Europe and China. Studies have shown that the fuel used by a vehicle has a significant impact on engine out emissions. In this study, nine fuels with varying chemical composition and physical properties were tested on a modern turbo-charged side-mounted GDI engine with design changes to reduce particulate emissions. The fuels tested included four fuels meeting US certification requirements; two fuels meeting European certification requirements; and one fuel meeting China 6 certification requirements being proposed at the time of this work.

Fuel chemistry plays a crucial role in the continued reduction of particulate emissions (PE) and cleaner air quality from vehicles and equipment powered by internal combustion engines (ICE). Over the past ten years, there have been great improvements in predictive particulate emissions indices (correlative mathematical models) based on the fuel’s composition. Examples of these particulate indices (PI) are the Honda Particulate Matter Index (PMI) and the General Motors Particulate Evaluation Index (PEI). However, the analytical chemistry lab methods used to generate data for these two PI indices are very time-consuming. Because gasoline can be mixtures of hundreds of hydrocarbon compounds, these lab methods typically include the use of the high resolution chromatographic separation techniques such as detailed hydrocarbon analysis (DHA), with 100m chromatography columns and long (3 - 4 hours) analysis times per sample.

The continuous improvement of internal combustion engines (ICEs) with strategies that can be applied to existing vehicle platforms, either directly or with minor modifications, can improve efficiency and reduce GHG emissions to help achieve Paris climate targets. Low carbon fuels (LCF) as diesel substitutes for light and heavy-duty vehicles are currently being considered as a promising alternative to reduce well-to-wheel (WTW) CO2 emissions by taking advantage of the carbon offset their synthesis pathway can promote, which could capture more CO2 than it releases into the atmosphere. Additionally, some low carbon fuels, like OMEx blends, have non-sooting properties that can significantly improve the NOx-soot tradeoff. The current work studies the calibration optimization of a EU6D-TEMP light-duty engine using various LCFs with different renewable contents with the goal of reduced NOx emissions.

Low-temperature gasoline combustion (LTGC) engines can deliver high efficiencies, with ultra-low emissions of nitrogen oxides (NOx) and particulate matter (PM). However, controlling the combustion timing and maintaining robust operation remains a challenge for LTGC engines. One promising technique to overcoming these challenges is spark assist (SA). In this work, well-controlled, fully premixed experiments are performed in a single-cylinder LTGC research engine at 1200 rpm using a cylinder head modified to accommodate a spark plug. Compression ratios (CR) of 16:1 and 14:1 were used during the experiments. Two different fuels were also tested, with properties representative of premium- and regular-grade market gasolines. SA was found to work well for both CRs and fuels. The equivalence ratio (ϕ) limits and the effect of intake-pressure boost on the ability of SA to compensate for a reduced Tin were studied. For the conditions studied, ϕ=0.42 was found to be most effective for SA.

The Particulate Matter Index (PMI) is a helpful tool which provides an indication of a fuel’s sooting tendency. Currently, the index is being used by various laboratories and OEMs as a metric to understand the gasoline fuels impact on both sooting found on engine hardware and vehicle out emissions. This paper will explore a new method that could be used to give indication of the sooting tendency of the gasoline range fuels, called the Particulate Evaluation Index (PEI), and provide the detailed equation in its initial form. In addition, the PEI will be shown to have a good correlation agreement to PMI. The paper will then give a detailed explanation of the data used to develop it. Initial vehicle PM/PN data will also be presented that shows correlations of the indices to the vehicle response.

With the implementation of the China VI gasoline standards, the use of ethanol is expanding and is intended to further reduce vehicle criteria gaseous and particulate emissions. However, due to the constraints of biomass ethanol production, petroleum derived Methyl tert-Butyl Ether (MTBE) is being used in addition to ethanol to improve fuel octane and maintain oxygen content. The impact of these mixed oxygenates on vehicle emissions are studied in this paper. The correlation of fuel characteristics to vehicle particulate emissions and their predictive indices has been investigated. The results from this study suggest some alternatives to existing fuel indices due to oxygenate contribution. Additionally, this paper studies, the emissions of three direct-injection turbocharged vehicle models focusing on particulate emissions from the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). The test fuels were China VIb gasoline, blended with different ratios of ethanol and MTBE.

Gasoline Particulate Filters (GPF) are widely employed in exhaust aftertreatment systems of gasoline engines to meet the stringent particulate emissions requirements of Euro 6 and China 6 standard. Optimization of GPF performance requires a delicate trade-off between fuel economy, engine performance and drivability. This results in a complex lengthy and iterative calibration development process which uses a lot of hardware resources. To improve the calibration process and reduce hardware testing, physics-based modeling of the GPF system is used. A 1-D chemical model supplemented with 3D CFD solver is utilized to evaluate pressure drop and soot burning performance characteristics of the GPF under engine dynamometer test conditions. The chemical kinetics of soot burning for the 1D model is developed using test data obtained from well controlled laboratory environment.

A gasoline’s chemical composition impacts a vehicle’s sooting tendency and therefore has been the subject of numerous emissions studies. From these studies, several mathematical correlation equations have been developed to predict a gasoline’s sooting tendency in modern spark-ignited internal combustion engine vehicles. This paper reviews the recently developed predictive tool methods and summarizes five years of global market fuel survey data to characterize gasoline sooting tendency trends around the world. Additionally, the paper will evaluate and suggest changes to the predictive methods to improve emissions correlations.

There have been tremendous improvements in China fuel quality in recent years in conjunction with newly implemented vehicle emissions standards to combat air pollution. The focus of concern is particulate emissions from gasoline engines especially from high volume gasoline direct inject (GDI) engines, therefore the China 6 (GB 18351.6-2016) emission standard introduces strict PM/PN requirements. Because the fuel and vehicle are an integrated system, the composition of gasoline is one of the factors affecting PM/PN emissions. Ethanol and aromatics are widely used as octane boosters, changing the composition of China’s gasoline pool. In this study, two gasoline oxygenates, ethanol and methyl tert-butyl ether (MTBE), and heavy aromatic hydrocarbons were studied in vehicles with a GDI engines. Vehicle tests were performed on the Worldwide Harmonized Light Vehicles Test Cycle (WLTC).

Gasoline Particulate Filters (GPF) are widely employed in exhaust aftertreatment systems of gasoline engines to meet the stringent particulate emissions requirements of Euro6 and China6 standard. While providing an effective filtration of particles, the GPF increases the engine backpressure as a penalty due to accumulation of soot. To clean the accumulated soot, periodical burning of soot is achieved by the onboard control models and lot of effort is spent on calibrating the same. In order to understand pressure drop behavior across GPF, detailed pressure drop measurements were conducted at clean, soot and ash loaded conditions at engine dynamometer and at vehicle conditions. Effect of degreening of GPF was studied to take into account any change in pressure drop characteristics of onboard control models during GPF aging in the vehicle.

A gasoline’s distillation profile is directly related to its hydrocarbon composition and the volatility (boiling points) of those hydrocarbons. Generally, the volatility profiles of U.S. market fuels are characterized using a very simple, low theoretical plate distillation separation, detailed in the ASTM D86 test method. Because of the physical chemistry properties of some compounds in gasoline, this simple still or retort distillation has some limitations: separating azeotropes, isomers, and heavier hydrocarbons. Chemists generally rely on chromatographic separations when more detailed and precise results are needed. High-boiling aromatic compounds are the primary source of particulate emissions from spark ignited (SI), internal combustion engines (ICE), hence a detailed understanding and high-resolution separation of these heavy compounds is needed.

De-fossilization is an increasingly important trend in the energy sector. In the transport sector the de-fossilization efforts have been centered in promoting the electrification of vehicles, nonetheless other pathways, like the use of carbon neutral or carbon-offsetting fuels under current vehicle fleets, are also worth considering. Low-carbon fuels (LCF) can be synthetized from sources that can take advantage of the carbon already present in the atmosphere (either by technologies like direct carbon capture or biological processes like photosynthesis in biofuels) and use energy from renewable sources for the necessary industrial processes. Although, LCFs can be compared to fossil fuels as energy sources for internal combustion engines, their composition is not the same and their properties can modify the engine combustion and emissions.