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In recognizing the potential for large, damaging impacts from climate change, California enacted Executive Order S-03-05, requiring a reduction in statewide greenhouse gas (GHG) emissions to 80% below 1990 levels by 2050. Given that the transportation light-duty vehicle (LDV) segment accounts for 28% of the state's GHG emissions today, it will be difficult to meet the 2050 goal unless a portfolio of near-zero carbon transportation solutions is pursued. Because it takes decades for a new propulsion system to capture a large fraction of the passenger vehicle market due to vehicle fleet turn-over rates, it is important to accelerate the introduction of these alternatives to ensure markets enter into early commercial volumes (10,000s) between 2015 and 2020. This report summarizes the results and conclusions of a modeling exercise that simulated GHG emissions from the LDV sector to 2050 in California.

Heavy-duty vehicles account for approximately 30 percent of the oxides of nitrogen (NOx) and 65 percent of the particulate matter (PM) emissions from the entire California on-road fleet, despite the fact that these vehicles comprise only 2 percent of the same. To meet legislative mandates to reduce excess smoke emissions from in-use heavy-duty diesel-powered vehicles, the Air Resources Board (ARB or Board) adopted, in December 1997, amendments to the regulations governing the operation and enforcement of the Heavy-Duty Vehicle Inspection Program (HDVIP or the “roadside” program) and the Periodic Smoke Inspection Program (PSIP or the “fleet” program). The initial roadside program was adopted in November 1990 in response to Senate Bill (SB) 1997 (stat. 1988, ch. 1544, Presley), and enforced from 1991 to 1993. It was suspended in October 1993, when the Board redirected staff to investigate reformulated fuels issues.

Two additive blends proposed for improving the flame luminosity in neat methanol fuel were investigated to determine the effect of these additives on the exhaust emissions in a dual-fueled Volkswagen Jetta. The two blends contained 4 percent toluene plus 2 percent indan in methanol and 5 percent cyclopentene plus 5 percent indan in methanol. Each blend was tested for regulated and unregulated emissions as well as a speciation of the exhaust hydrocarbons resulting from use of each fuel. The vehicle exhaust emissions from these two fuel blends were compared to the Coordinating Research Council Auto-Oil national average gasoline (RF-A), M100, and M85 blended from RF-A. Carter Maximum Incremental Reactivity Factors were applied to the speciated hydrocarbon emission results to determine the potential ozone formation for each fuel. Toxic emissions as defined in the 1990 Clean Air Act were also compared for each fuel.

While most studies addressing the fuel effects are based on the Federal Test Procedure (FTP), there are limited studies investigating the fuel effects outside FTP test conditions. In this study, we investigated the differences in exhaust emissions from California Phase 1 to Phase 2 reformulated gasoline over a wide range of speed and ambient temperatures. Eleven catalyst equipped passenger vehicles were tested. The vehicles were comprised of three fuel delivery system configurations, namely, three from carburetor (CARBU), three from throttle body injection (TBI), and five from multi-port fuel injection (MPFI) group. Each vehicle was given 60 tests with the combination of two reformulated fuels: Phase 1 (without oxygenates) and Phase 2 (with oxygenates), three temperatures (50, 75, and 100 °F), and ten speed cycles (average speed ranges from 4 mph to 65 mph).

The introduction of biofuels is seen as a very important measure to reduce the emissions of greenhouse gases from the transport sector. Currently, ethanol is the most widely used renewable fuel for transportation in the US and with the push to use increasingly higher levels of renewable fuels, there has been an accompanying push to further increase the ethanol level in gasoline. In addition to ethanol, butanol, an alcohol which can be produced from biomass sources, has recently received more attention as an alternative to gasoline for use in spark ignition (SI) engines. For this study, two 2007 model year and one 2012 model year light-duty vehicles equipped with a three-way catalyst (TWC) were employed. For the 2007 model year vehicles, emissions and fuel economy measurements were made for E10 (reference fuel), E15, E20, and B16 fuels. The latter corresponds to a blend of gasoline and 16% of butanol, which is the equivalent of E10 in terms of oxygen content.

Light duty gasoline vehicles (LDGV) are estimated to contribute 40% of the total on-road mobile source tailpipe emissions of particulate matter (PM) in California. While considerable efforts have been made to reduce toxic diesel PM emissions going into the future, less emphasis has been placed on PM from LDGVs. The goals of this work were to characterize a small fleet of visibly smoking and high PM emitting LDGVs, to explore the potential PM-reduction benefits of Smog Check and of repairs, and to examine remote sensing devices (RSD) as a potential method for identifying high PM emitters in the in-use fleet. For this study, we recruited a fleet of eight vehicles covering a spectrum of PM emission levels. PM and criteria pollutant emissions were quantified on a dynamometer and CVS dilution tunnel system over the Unified Cycle using standard methods and real time PM instruments.

Chrysler, Ford, General Motors, the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) have collaborated over the past two years to develop an efficiency test for mobile air conditioner (MAC) systems. Because the effect of efficiency differences between different MAC systems and different technologies is relatively small compared to overall vehicle fuel consumption, quantifying these differences has been challenging. The objective of this program was to develop a single dynamic test procedure that is capable of discerning small efficiency differences, and is generally representative of mobile air conditioner usage in the United States. The test was designed to be conducted in existing test facilities, using existing equipment, and within a sufficiently short time to fit standard test facility scheduling. Representative ambient climate conditions for the U.S. were chosen, as well as other test parameters, and a solar load was included.

The Automotive Industry/Government Emissions Research CRADA (AIGER) has been working to develop a new methodology for the direct determination of nonmethane hydrocarbons (DNMHC) in vehicle testing. This new measurement technique avoids the need for subtraction of a separately determined methane value from the total hydrocarbon measurement as is presently required by the Code of Federal Regulations. This paper will cover the historical aspects of the development program, which was initiated in 1993 and concluded in 2002. A fast, gas chromatographic (GC) column technology was selected and developed for the measurement of the nonmethane hydrocarbons directly, without any interference or correction being caused by the co-presence of sample methane. This new methodology chromatographically separates the methane from the nonmethane hydrocarbons, and then measures both the methane and the backflushed, total nonmethane hydrocarbons using standard flame ionization detection (FID).

This study investigates the impact of low concentration biodiesel blends on the regulated and polycyclic aromatic hydrocarbon (PAH) emissions from a modern passenger vehicle. The vehicle was Euro 4 compliant fitted with a direct injection common-rail diesel engine and a diesel oxidation catalyst. Emission and fuel consumption measurements were performed on a chassis dynamometer using constant volume sampling (CVS) technique, following the European regulations. All measurements were conducted over the type approval New European Driving Cycle (NEDC) and the real-traffic-based Artemis driving cycles. Aiming to evaluate the fuel impact on emissions, a soy-based, a palm-based, and a rapeseed oil-based biodiesel were blended with an ultra-low sulfur diesel at proportions of 10, 20, and 30% by volume. The experimental results revealed that emissions of PM, HC and CO decreased with biodiesel over most driving conditions.

Gaseous and particulate matter (PM) emissions were assessed from two current technology heavy-duty vehicles operated on CARB ultra-low sulfur diesel (ULSD), hydrotreated vegetable oil (HVO) blends, and a biodiesel blend. Testing was performed on a 2014 model year Cummins ISX15 vehicle and on a 2010 model year Cummins ISB6.7 vehicle. Both vehicles were equipped with diesel oxidation catalysts (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) systems. Testing was conducted over the Heavy-Duty Urban Dynamometer Driving Schedule (UDDS) and Heavy Heavy-Duty Diesel Truck (HHDDT) Transient Cycle. The results showed lower total hydrocarbons (THC), non-methane hydrocarbons (NMHC), and methane (CH4) emissions for the HVO fuels and the biodiesel blend compared to CARB ULSD. Overall, nitrogen oxide (NOx) emissions showed discordant results, with both increases and decreases for the HVO fuels.

A novel in situ method was performed for measuring emissions and fuel consumption of transport refrigeration units (TRUs). The test matrix included two fuels, two exhaust configurations, and two TRU engine operating speeds. The test fuels were California ultra low sulfur diesel and gas-to-liquid (GTL) diesel. The exhaust configurations were a stock original equipment manufacturer (OEM) muffler and a Thermo King pDPF™ diesel particulate filter. The two TRU engine operating speeds were high and low, as controlled by the TRU user interface. Test results indicate that GTL diesel fuel reduces all regulated emissions at high and low engine operating speeds. Separately, the application of a Thermo King pDPF reduced regulated emissions, in some cases almost entirely. Finally, the application of both GTL diesel and a Thermo King pDPF reduced regulated emissions at high engine operating speed, but with an increase in oxides of nitrogen (NOx) at low engine speed.

The Environmental Protection Agency (EPA) is developing emission standards for nonroad spark-ignition engines rated over 19 kW. Existing emission standards adopted by the California Air Resources Board for these engines were derived from emission testing with new engines, with an approximate adjustment applied to take deterioration into account. This paper describes subsequent testing with two LPG-fueled engines that had accumulated several thousand hours of operation with closed-loop control and three-way catalysts. These engines were removed from forklift trucks for characterization and optimization of emission levels. Emissions were measured over a wide range of steady-state points and several transient duty cycles. Optimized emission levels from the aged systems were generally below 1.5 g/hp-hr THC+NOx and 10 g/hp-hr CO.

When the California Air Resources Board (ARB) adopted automotive exhaust emission standards for Super Ultra-Low-Emission Vehicles (SULEV), new challenges were encountered for accurately measuring exhaust emissions. This is especially true for measuring NMOG emissions (NMHC and carbonyls) where the SULEV standard is 0.010 g/mi. One of the challenges in accurately measuring NMHC emissions is to find a clean sample bag material that has no or very low outgassing of hydrocarbons. Tedlar, the bag material commonly used for exhaust emission sampling, has been found to emit N,N- dimethylacetamide (DMAc), which interferes with hydrocarbon measurements and can contribute to significant error in SULEV hydrocarbon emission measurements. Several fluorocarbon materials were tested for hydrocarbon (HC) outgassing and carbon dioxide (CO2) permeation. The materials include Tedlar, Baked Tedlar, KynarFlex 2750, Baked KynarFlex 2800, Teflon FEP, TFM TFE, Tefzel, and Halar.

The impact of biodiesel and new generation biofuels on emissions from heavy-duty diesel engines was investigated using a California Air Resources Board (CARB) certified diesel fuel as a base fuel. This study was performed on two heavy-duty diesel engines, a 2006 engine and a diesel particle filter (DPF) equipped 2007 engine, on an engine dynamometer over four different test cycles. Emissions from soy-based and animal-based biodiesel, renewable diesel fuel, and gas-to-liquid (GTL) diesel fuel were evaluated at blend levels ranging from 5 to 100%. Consistent with previous studies, particulate matter (PM), hydrocarbons (HC), and carbon monoxide (CO) emissions generally showed increasing reductions with increasing biodiesel and renewable/GTL diesel fuel blend levels for the non-DPF equipped engine. The levels of these reductions were generally comparable to those found in previous studies performed using more typical Federal diesel fuels.

The California Air Resources Board conducted an extensive field test program to evaluate a vehicle exhaust recirculation system for control of oxides of nitrogen. The system utilized hot exhaust gases from the crossover and included certain modifications to the carburetion, choke, and crank case ventilation system. It was tested on two fleets of automobiles equipped wtih California approved HC and CO emission control devices. The test program involved periodic measurements of exhaust emissions and fuel consumption. The effect of the system on vehicle drivability, engine deposits, wear, and oil deterioration was also studied. The Atlantic Richfield Company, under contract to the Air Resources Board, equipped the vehicles with the recirculation system and performed the final engine inspection.

The use of methanol as a “clean fuel” appears to be a viable approach to reduce air pollution. However, concern has been expressed about potentially high formaldehyde emissions from stoichiometrically operated light-duty vehicles. This paper presents results from an emission test program conducted for the California Air Resources Board (CARB) and the South Coast Air Quality Management District (SCAQMD) to identify and evaluate advanced catalyst technology to reduce formaldehyde emissions without compromising regulated emission control. An earlier paper presented the results of evaluating eighteen different catalyst systems on a hybrid methanol-fueled test vehicle. (1)* This paper discusses the optimization of three of these catalyst systems on four current technology methanol-fueled vehicles. Emission measurements were conducted for formaldehyde, nonmethane organic gases (NMOG), methanol, carbon monoxide, and oxides of nitrogen emissions.

This paper covers work performed for the California Air Resources Board and US Environmental Protection Agency by Southwest Research Institute. Emission measurements were made on four in-use off-road two-stroke motorcycles and all-terrain vehicles utilizing oxygenated and non-oxygenated fuels. Emission data was produced to augment ARB and EPA's off-road emission inventory. It was intended that this program provide ARB and EPA with emission test results they require for atmospheric modeling. The paper describes the equipment and engines tested, test procedures, emissions sampling methodologies, and emissions analytical techniques. Fuels used in the study are described, along with the emissions characterization results. The fuel effects on exhaust emissions and operation due to ethanol content and fuel components is compared.

We assessed gaseous and particulate matter (PM) emissions from a current technology stoichiometric natural gas waste hauler equipped with a 2011 model year 8.9L Cummins Westport ISL-G engine with cooled exhaust gas recirculation (EGR) and three-way catalyst (TWC). Testing was performed on five fuels with varying Wobbe and methane numbers over the William H. Martin Refuse Truck Cycle. The results showed lower nitrogen oxide (NOx) emissions for the low methane fuels (i.e., natural gas fuels with a relatively low methane content) for the transport and curbside cycles. Total hydrocarbon (THC) and methane (CH4) emissions did not show any consistent fuel trends. Non-methane hydrocarbon (NMHC) emissions showed a trend of higher emissions for the fuels containing higher levels of NMHCs. Carbon monoxide (CO) emissions showed a trend of higher emissions for the low methane fuels.

Gasohol, a blend of 90 percent unleaded gasoline and 10 percent ethanol, has been represented as an alternative to pure gasoline which can reduce the nation’s crude oil dependence. However, a systems analysis of the gasohol production processes indicates that gasohol is increasing rather than decreasing the nation’s dependence on crude oil. Alternative uses of the petroleum and natural gas currently used to manufacture ethanol would reduce the nation’s demand for oil. At the present time, every gallon of crude oil “saved” by substituting ethanol for gasoline results in a need to import approximately two gallons of crude oil. The federal government’s claim that gasohol can reduce the nation’s dependence on imported energy appears, to be based principally on political considerations, but also on the assumption that coal will eventually replace the petroleum and natural gas currently used in the gasohol production wherever possible.

The measurement of solid particles down to 10 nm is being incorporated into global technical regulations (GTR). This study explores the measurement of solid particles below 23 nm by using both current and proposed particle number (PN) systems having different volatile particle remover (VPR) methodologies and condensation particle counter (CPC) cutoff diameters. The measurements were conducted in dynamometer test cells using ten diesel and eight natural gas (NG) engines that were going under development for a variety of global emission standards. The PN systems measured solid PN from more than 700 test cycles. The results from the preliminary campaign showed a 10-280% increase in PN emissions with the inclusion of particles below 23 nm.