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Update on light-duty regulations. Presenter Michael J. McCarthy, California Air Resources Board

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.

Present motor vehicle particulate matter (PM) emission measurement regulations (Code of Federal Regulations (CFR) 40 Part 1065, 1066) require gravimetric determination of PM mass collected onto filter media from dilute exhaust. To improve the current sampling and measurement procedures for TIER 3 PM emissions standard of 3 mg/mile, CFR part 1066 adopted five alternative PM sampling options. One option of great interest is sampling the entire test using a single flow-weighed filter rather than the conventional three-filter (one filter per test phase) approach. The single filter method could lessen the time needed for gravimetric determination by reducing the quantity of filters used for a test and possibly reduce the uncertainty in gravimetric measurements, particularly at sub 1 mg/mile PM levels. This study evaluates the single filter and, to a limited extent, the 2-filter alternatives adopted in 40 CFR Part 1066.

The California Air Resources Board requires that new California vehicles be equipped with on-board diagnostic (OBD) systems. Starting with the 1988 models, these systems were required on new passenger cars, light-duty trucks and medium-duty vehicles equipped with three-way catalysts and feed-back fuel controls. The purpose of the OBD system is to expedite the proper repair of emission-related malfunctions and, thus, reduce vehicle emissions. When malfunctons are detected, a malfunction indicator light (MIL) mounted in the dash panel illuminates cautioning the vehicle operator that a repair is needed. Also, a fault code is stored in the OBD computer memory. When the vehicle is brought to a repair facility, the fault code provides the mechanic with the likely areas of malfunction for repairing the vehicle. After the repair is performed, the fault code is cleared, the MIL is extinguished, and the OBD system will subsequently confirm if the proper repair has been performed.

Since the mid-1990s, light-duty vehicles equipped with gasoline direct injection (GDI) engines have been added to the vehicle fleet in increasing numbers. Compared to conventional port fuel injection (PFI) engines, GDI engines provide higher power output for the same size engine, higher fuel efficiency, and lower carbon dioxide (CO₂) emissions. Due to the paucity of particulate matter (PM) emission data for light-duty gasoline vehicles in general and the increasing interest in these emissions relative to climate and air quality concerns, it is important to investigate PM emissions from current-generation GDI technologies. In this study, nine 2007-2010 light-duty GDI vehicles equipped with either wall-guided or spray-guided fuel injection systems were tested using California commercial gasoline fuel containing six percent ethanol by volume. Criteria pollutants including gaseous and PM emissions were measured over the Federal Test Procedure (FTP) transient test cycle.

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.

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.

Particulate matter (PM) emitted from light-duty gasoline powered vehicles is under increasing scrutiny due to potential adverse health effects and on ever increasing number of vehicles in the fleet. In this program, a group of California ULEV II and SULEV II certified light-duty gasoline vehicles were tested for PM mass and number emissions and compared with older model LEV I certified gasoline vehicles under the Federal Test Procedure (FTP) test cycle. PM mass and number emissions were collected from a Constant Volume Sampling (CVS) full dilution system. PM mass samples were collected with the gravimetric method. Filter conditioning and weighing procedures are in compliance with the Code of Federal Regulations (CFR) Part 1065. Total particles (solid and volatile) were measured using multiple fast response particle counting instruments including a TSI Engine Exhaust Particle Sizer (EEPS) and two Condensation Particle Counters (CPC).

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 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.

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).

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.

As automotive exhaust emission standards have become more stringent and emission control technologies have advanced over the years, accurately measuring the resulting near zero emissions has become increasingly difficult. To improve measurement accuracy, enhancements have been made to the conventional Constant Volume Sampling system (CVS) and to the analytical instrumentation This study included the evaluation of a CVS enhancement. Specifically, a prototype air filter was utilized to enhance the performance of a CVS by reducing non-methane hydrocarbons (NMHC) from dilution air at ambient temperature. Also incorporated into this study was the assessment of a Bag Mini-Dilute (BMD), a relatively new sampling system developed for measuring low-level vehicle emissions. The BMD can be used as an alternative to the CVS and has been approved for emission measurement by the United States Environmental Protection Agency (US EPA) and the California Air Resources Board (ARB.)

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.

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 goal of the project was to reduce tailpipe-out hydrocarbon (HC) plus oxides of nitrogen (NOx) emissions to 50 percent or less of the current California Air Resources Board (CARB) useful life standard of 12 g/hp-hr for Class I engines, or 9 g/hp-hr for Class II engines. Low-emission engines were developed using three-way catalytic converters, passive secondary-air induction (SAI) systems, and in two cases, enleanment. Catalysts were integrated into the engine's mufflers, where feasible, to maintain a compact package. Due to the thermal sensitivity of these engines, carburetor calibrations were left unchanged in four of the six engines, at the stock rich settings. To enable HC oxidation under such rich conditions, a simple passive supplemental air injection system was developed. This system was then tuned to achieve the desired HC+NOx reduction.

Programs to control motor vehicle emissions originated in California as a result of Professor A.J. Haagen-Smit of the California Institute of Technology discovering that two invisible automobile emissions, hydrocarbons and oxides of nitrogen, react together in the presence of sunlight to form oxidants such as ozone, a principal ingredient of the infamous Los Angeles area “smog”. The State of California became the first government to regulate the emissions of new automobiles when it adopted requirements for the use of positive crankcase ventilation (PCV) valves beginning with the 1963 model year.

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.

There have been a half dozen surveys performed by the California Air Resources Board in California from December, 1977 to July, 1982 to determine the rate of vehicle misfueling in California. There has been great concern raised over misfueling which leads to the poisoning of catalysts and the subsequent increases in emissions of hydrocarbons, carbon monoxide and oxides of nitrogen. The results of observing refueling at service stations indicate a misfueling rate of about 2% which is much lower than what the U. S. Environmental Protection Agency figures indicate. Misfueling at self-serve stations is more than twice that noted at full-serve stations. The primary reasons given by motorists for misfueling are cheaper price of unleaded gasoline, performance (including pinging) and unavailability of unleaded fuel. Misfueling was accomplished primarily as a result of a modified restrictor or filler neck.

An analysis of data provided by-vehicle manufacturers during the California emissions certification process has been performed for 1983-1987 model-year light-duty vehicles. The major change in emission control system design was a decrease in the use of secondary air injection which was used on 75% of 1983 vehicles, but only 50% of 1986 and 1987 vehicles. Exhaust gas recirculation was used on 90% of vehicles from 1983-1987. The sales-weighted certification emission levels of gasoline-powered light-duty vehicles were 0.23 g/mile HC, 3.1 g/mile CO, and 0.5 g/mile NOx in 1983. Levels of HC and CO were approximately constant at 0.20 g/mile and 2.7 g/mile, respectively, from 1984-1987 with NOx levels decreasing to 0.4 g/mile for 1987.