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A survey of vehicle refueling practices in California during the gasoline shortage of 1979 indicates that the use of leaded gasoline in catalyst equipped vehicles was occurring at a rate of about 1.6%. This 1.6% “misfueling” rate is lower than has been predicted by the U.S. Environmental Protection Agency and is almost exclusively the result of the refueling that occurs at self-service gasoline pumps. About three-quarters of the misfueled vehicles were apparently operated on leaded gasoline routinely. Based on the effect that leaded fuel has on the exhaust emission characteristics of catalyst equipped vehicles it is estimated that misfueling in California is increasing hydrocarbon and carbon monoxide emissions by about 4% and 1.6%, respectively from late model passenger cars.

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.

Current California law requires the implementation of a mandatory annual vehicle emissions inspection and maintenance program in the South Coast Air Basin by 1978. The pilot phase of this inspection program is now in operation in the City of Riverside. This paper evaluates the Riverside program and an alternate program for their abilities to detect gross emitters and provide cost/effective emissions reductions. A surveillance program was conducted to evaluate the Riverside loaded-mode inspection regime and an alternate idle inspection regime. Emissions and fuel economy tests indicated that there was no significant difference between the two regimes. Each regime resulted in immediate reductions on repaired vehicles of 35-40% in hydrocarbon emissions and 30-35% in carbon monoxide emissions, with no significant change in oxides of nitrogen emissions. There was a small (1-4%) improvement in fuel economy, and the average repair cost was $20-25.

As the standards for exhaust emissions have become more stringent, the quality control tools used to evaluate the performance of low level samplers and analyzers has become more important. The Vehicle Exhaust Emissions Simulator (VEES) was developed to evaluate the performance of vehicle or engine exhaust emissions sampling and analytical systems. The simulator emulates emissions from low-emitting gasoline vehicles by producing a simulated exhaust stream containing emission constituents (HC, CO, CO2, and NOx) injected via Mass Flow Controllers (MFCs). This paper discusses various applications of the VEES as a quality control tool for ULEV and SULEV testing. A comparison is made between the injected amount of exhaust species by the VEES and the amounts recovered by the different sampling systems. Different root cause scenarios are discussed as to the source of discrepancies between the results on the CVS and BMD for different driving cycles.

Vehicle exhaust emissions measurements are reported for full-size panel vans operating on four alternative motor fuels and control gasoline. The emissions tests produced data on in-use vans. The vans were taken directly from commercial delivery service for testing as they accumulated mileage over a 24-month period. The alternative fuels tested were compressed natural gas, propane gas, California Phase 2 reformulated gasoline (RFG), and methanol (M-85 with 15 percent RFG). The control gasoline for the emissions tests was an industry average unleaded blend (RF-A). The vehicle technologies tested represent those options available in 1992 that were commercially available from Ford, Chrysler, and Chevrolet or which these manufacturers agreed to provide as test vans for daily use in commercial service by FedEx.

It is becoming increasingly difficult to obtain good repeatability from running lab vehicle correlation testing, since vehicle variability is so significant at the Low ULEV and SULEV emissions levels. These new emission standards are becoming so stringent that it makes it very difficult to distinguish whether a problem is a result of vehicle variability, test cell sampling or the analytical system. A vehicle exhaust emission simulator (VEES) developed by Horiba, can simulate emissions from low emitting gasoline vehicles by producing tailpipe flow rates containing emissions constituents ( HC, CH4, CO, NOx, CO2 ) injected at the tailpipe flow stream via mass flow controllers.

An accurate air flow rate model is critical for high-quality air-fuel ratio control in Spark-Ignition engines using a Three-Way-Catalyst. Emerging Variable Valve Timing technology complicates cylinder air charge estimation by increasing the number of independent variables. In our previous study (SAE 2004-01-3054), an Artificial Neural Network (ANN) has been used successfully to represent the air flow rate as a function of four independent variables: intake camshaft position, exhaust camshaft position, engine speed and intake manifold pressure. However, in more general terms the air flow rate also depends on ambient temperature and pressure, the latter being largely a function of altitude. With arbitrary cam phasing combinations, the ambient pressure effects in particular can be very complex. In this study, we propose using a separate neural network to compensate the effects of altitude on the air flow rate.

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.

The California Air Resources Board (CARB) has tested the utility of the Model 3090 Engine Exhaust Particle Sizer (EEPS™) by TSI in measuring pre- and post-trap particulate matter (PM) emissions from a medium-duty truck. Pre- and post-trap measurements are used to evaluate the effect of engine operation on PM emissions and trap effectiveness. Because of mounting evidence that ultrafine (UF) particles are harmful, regulatory agencies are investigating new and promising instrumentation for improved characterization of such particles in emissions. This is especially true for fast-response instruments that can be used to size-resolve real-time UF emissions from prominent sources such as diesel engines. The EEPS uses diffusion charging, electrical mobility segregation, and electrometers. It is designed for the number measurement of transient aerosols in the size range of 5.6 to 560 nm. It collects 10 measurements per second at a flow rate of 10 lpm.

A project was conducted by Southwest Research Institute on behalf of the California Air Resources Board and the South Coast Air Quality Management District to demonstrate the technical feasibility of utilizing closed-loop three-way catalyst technology in off-road equipment applications. Five representative engines were selected, and baseline emission-tested using both gasoline and LPG. Emission reduction systems, employing three-way catalyst technology with electronic fuel control, were designed and installed on two of the engines. The engines were then installed in a fork lift and a pump system, and limited durability testing was performed. Results showed that low emission levels, easily meeting CARB's newly adopted large spark-ignited engine emission standards, could be achieved.

The existence of the cyclic variation of the flow inside an cylinder affects the performance of the engine. Developing methods to understand and control in-cylinder flow has been a goal of engine designers for nearly 100 years. In this paper, passive control of the intake flow of a 3.5-liter DaimlerChrysler engine was examined using a unique optical diagnostic technique: Molecular Tagging Velocimetry (MTV), which has been developed at Michigan State University. Probability density functions (PDFs) of the normalized circulation are calculated from instantaneous planar velocity measurements to quantify gas motion within a cylinder. Emphasis of this work is examination of methods that quantify the cyclic variability of the flow. In addition, the turbulent kinetic energy (TKE) of the flow on the tumble and swirl plane is calculated and compared to the PDF circulation results.

A cooperative vehicle exhaust emissions test program was conducted by the California Air Resources Board and Chevron Research and Technology Company. The focus of the program was to determine the effect of aromatics content on nitrogen oxides (NOx) emissions. The program consisted of testing nine vehicles on three different fuels. The fuels ranged in aromatics content from 10% to 30%.* Other fuel properties were held as constant as possible. The tests were conducted in two different laboratories. In addition to the measurement of criteria emissions (hydrocarbons, carbon monoxide, and NOx), some of the hydrocarbon emissions were speciated and a reactivity of the exhaust was calculated. Only slight changes in the exhaust emissions and reactivity were observed for a change in aromatics content from 30% to 10%.

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.

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).

Heavy duty diesel vehicle (HDDV) emissions are known to affect air quality, but few studies have quantified the real-world contribution to the inventory. The objective of this study was to provide data that may enable ambient emissions investigators to m,odel the air quality more accurately. The 25 vehicles reported in this paper are from the first phase of a program to determine representative regulated emissions from Heavy Heavy-Duty Diesel Trucks (HHDDT) operating in Southern California. Emissions data were gathered using a chassis dynamometer, full flow dilution tunnel, and research grade analyzers. The subject program employed two truck test weights and four new test modes (one was idle operation), in addition to the Urban Dynamometer Driving Schedule (UDDS), and the AC50/80 cycle. The reason for such a broad test cycle scope was to determine thoroughly how HHDDT emissions are influenced by operating cycle to improve accuracy of models.

The way a powertrain is mounted plays an important role in improving vehicle noise and vibration caused by the engine firing forces and can be an effective role in improving vehicle ride comfort. This paper describes the basic concepts in powertrain mounting and derives a new concept of evaluating powertrain mounting. It is well known in publications that a decoupled powertrain mounting system has better NVH characteristics[3][4][6]. But how to relate percentage of decouple to powertrain mounts transmitted forces, what “decoupled” really means, and how to evaluate how much it is decoupled are still ambiguous to many engineers. The traditional “one coordinate system” kinetic energy fraction (KEF) index can't give a clear picture of how much the engine mounting is decoupled and is often misleading. The new concept focuses on the excitations acting on the powertrain system.

The use of a partial flow sampling system (PFSS) to measure nonroad steady-state diesel engine particulate matter (PM) emissions is a technique for certification approved by a number of regulatory agencies around the world including the US EPA. Recently, there have been proposals to change future nonroad tests to include testing over a nonroad transient cycle. PFSS units that can quantify PM over the transient cycle have also been discussed. The full flow constant volume sampling (CVS) technique has been the standard method for collecting PM under transient engine operation. It is expensive and requires large facilities as compared to a typical PFSS. Despite the need for a cheaper alternative to the CVS, there has been a concern regarding how well the PM measured using a PFSS compared to that measured by the CVS. In this study, three PFSS units, including AVL SPC, Horiba MDLT, and Sierra BG-2 were investigated in parallel with a full flow CVS.

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).

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.

As SULEV emission regulations approach, the bag mini-diluter (BMD) technology is gaining acceptance as a replacement for the existing constant volume sampler (CVS) for SULEV exhaust emission measurement and certification. The heart of the BMD system is the direct vehicle exhaust (DVE) flow measurement system. Due to the transient nature of vehicle exhaust during a standard FTP emission test cycle, the DVE must be capable of rapid and accurate response in order to track these varying exhaust flow rates. The DVE must also be robust enough to accurately measure flow rate despite variations in exhaust gas composition, pulsation effects, and rapid changes in both exhaust temperature and pressure. One of the primary DVE systems used on BMDs is the E-Flow, an ultrasonic flow meter manufactured by Flow Technologies, Inc.