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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.

Recently, a new technology, termed 2-way SCR/DPF by the authors, has been developed by several catalyst suppliers for diesel exhaust emission control. Unlike a conventional emission control system consisting of an SCR catalyst followed by a catalyzed DPF, a wall-flow filter is coated with SCR catalysts for controlling both NOx and PM emissions in a single catalytic converter, thus reducing the overall system volume and cost. In this work, the potential and limitations of the Cu/Zeolite-based SCR/DPF technology for meeting future emission standards were evaluated on a pick-up truck equipped with a prototype light-duty diesel engine.

A fully flexible valve actuation (FFVA) system was developed for a single cylinder research engine to investigate high efficiency clean combustion (HECC) in a diesel engine. The main objectives of the study were to examine the emissions, performance, and combustion characteristics of the engine using late intake valve closing (LIVC) to determine the benefits and limitations of this strategy to meet Tier 2 Bin 5 NOx requirements without after-treatment. The most significant benefit of LIVC is a reduction in particulates due to the longer ignition delay time and a subsequent reduction in local fuel rich combustion zones. More than a 95% reduction in particulates was observed at some operating conditions. Combustion noise was also reduced at low and medium loads due to slower heat release. Although it is difficult to assess the fuel economy benefits of LIVC using a single cylinder engine, LIVC shows the potential to improve the fuel economy through several approaches.

This paper summarizes the Heavy-Duty In-Use Testing (HDUIT) measurement allowance program for Particulate Matter Portable Emissions Measurement Systems (PM-PEMS). The measurement allowance program was designed to determine the incremental error between PM measurements using the laboratory constant volume sampler (CVS) filter method and in-use testing with a PEMS. Two independent PM-PEMS that included the Sensors Portable Particulate Measuring Device (PPMD) and the Horiba Transient Particulate Matter (TRPM) were used in this program. An additional instrument that included the AVL Micro Soot Sensor (MSS) was used in conjunction with the Sensors PPMD to be considered a PM-PEMS. A series of steady state and transient tests were performed in a 40 CFR Part 1065 compliant engine dynamometer test cell using a 2007 on-highway heavy-duty diesel engine to quantify the accuracy and precision of the PEMS in comparison with the CVS filter-based method.

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%.

A study was conducted by the California Air Resources Board to investigate the effects that altitude has on in-use heavy-duty diesel truck smoke opacities. The understanding of these effects may allow for the establishment of a high altitude opacity standard for diesel trucks operating at or above altitudes of 5800 feet. During a three-week study, 170 heavy-duty diesel trucks were tested at an altitude of 5,820 feet using a test procedure consisting of rolling acceleration and snap idle tests. Eighty-four (84) of these trucks were recaptured and retested at an altitude of 125 feet. Results from a regression analysis indicates that, on average, truck smoke opacities increased by 23 opacity points when tested at altitudes near 6000 feet. Possible high altitude cutpoints and failure rates are also discussed.

Emissions from heavy-duty vehicles are a major contributor to California's air quality problems. Emissions from these vehicles account for approximately 30% of the nitrogen oxide and 75% of the particulate matter emissions from the entire on-road vehicle fleet. Additionally, excessive exhaust smoke from in-use heavy-duty diesel vehicles is a target of numerous public complaints. In response to these concerns, California has adopted an in-use Heavy-Duty Vehicle Smoke and Tampering Inspection Program (HDVIP) designed to significantly reduce emissions from these vehicles. Pending promulgation of HDVIP regulations, vehicles falling prescribed test procedures and emission standards will be issued citations. These citations mandate expedient repair of the vehicle and carry civil penalties ranging from $300 to $1800. Failure to clear citations can result in the vehicle being removed from service.

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.

The GREEN-MAC-LCCP© [Global Refrigerants Energy & Environmental - Mobile Air Condition - Life Cycle Climate Performance] model described here is an evolution of a previous GM model that assesses the lifecycle energy and GHG emissions associated with the production, use and disposal of alternative refrigerants and MAC components. This new model reduces the complexity of inputs and provides a consistent output analysis. This model includes Microsoft Excel Visual Basic© code to automatically make the calculations once inputs are complete.

Global environmental and economic concerns regarding increasing fuel consumption and greenhouse gas emission are driving changes to legislative regulations and consumer demand. As regulations become more stringent, advanced engine technologies must be developed and implemented to realize desired benefits. Discrete variable valve lift technology is a targeted means to achieve improved fuel economy in gasoline engines. By limiting intake air flow with an engine valve, as opposed to standard throttling, road-load pumping losses are reduced resulting in improved fuel economy. This paper focuses on the design and development of a switching roller finger follower system which enables two mode discrete variable valve lift on end pivot roller finger follower valvetrains. The system configuration presented includes a four-cylinder passenger car engine with an electro-hydraulic oil control valve, dual feed hydraulic lash adjuster, and switching roller finger follower.

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.

The new regulations to reduce emissions have resulted in the development of new techniques to maintain or enhance competitive performance. A requirement for the manifold is to help meet the reduction in cold start emissions, particularly during the transient conditions from start to 100 seconds following the Federal Test Procedures for vehicle emissions. Finite element computer models were developed to predict inner and outer wall temperatures, and to determine structural soundness. Tests were performed to assure that noise levels were minimized. Dynamometer lab and field tests were performed to verify that the manifold would meet the design requirements. From the results of these tests and analyses, modifications were made to the weld and manufacturing techniques to improve product life and reduce noise. Dual wall manifolds have proven durability to meet high exhaust gas temperatures up to 1650°F (900°C), while meeting the performance, noise, and weight reduction goals.

This paper examines the aerodynamic forces on the open hood of a stationary vehicle when another large vehicle, such as an 18-wheel semi-truck, passes by at high speed. The problem of semi-truck passing a parked car with hood open is solved as a transient two-vehicle aerodynamics problem with a Dynamic Moving Mesh (DMM) capability in commercial CFD software package FLUENT. To assess the computational feasibility, a simplified compact car / semi-truck geometry and CFD meshes are used in the first trial example. At 70 mph semi-truck speed, the CFD results indicate a peak aerodynamic force level of 20N to 30N on the hood of the car, and the direction of the net forces and moments on the hood change multiple times during the passing event.

Due to competitive pressures and the need to rapidly develop new products for the automotive marketplace, the automotive industry has to rapidly develop and validate automotive subsystems and components. While many CAE tools are employed to decrease the time needed for a number of brake engineering tasks such as stress analysis, brake system sizing, thermo-fluid analysis, and structural dynamics, brake lining wear and the associated concept of “lining life” are still predominantly developed and validated through resource intensive public road vehicle testing. The goal of this paper is to introduce and detail an energy-based, lumped-parameter CAE approach to predict brake lining life in passenger cars and light trucks.

In an endeavor to improve upon historically subjective and hardware-based steering tuning development, a team was formed to find an optimal and objective solution using Design For Six Sigma (DFSS). The goal was to determine the best valve assembly design within a hydraulic power-steering assist system to yield improved steering effort and feel robustness for all vehicle models in a future truck program. The methodology utilized was not only multifaceted with several Design of Experiments (DOEs), but also took advantage of a CAE-based approach leveraging modeling capabilities in ADAMS for simulating full-vehicle, On-Center Handling behavior. The team investigated thirteen control factors to determine which minimized a realistic, compounded noise strategy while also considering the ideal steering effort function (SEF) desired by the customer. In the end, it was found that response-dependent variability dominated the physics of our valve assembly design concept.

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.

The sampling protocol proposed by the international PMP program for determination of particle emissions from clean light-duty vehicles was applied to the emissions from a California heavy-duty trap-equipped diesel truck. CARB is interested in developing opinions about the potential of this new European approach for emission determination and in exploring its utility for use in California. In this exercise, the use of various commercially available instruments for counting and sizing particles in the context of the PMP recommendations are explored. A single vehicle on a chassis dynamometer was exercised over steady-state and transient cycles. Multiple measurements of gaseous, mass, and particle emissions were collected in order to determine statistical significance. The PMP approach yielded particle emission measurements with higher precision and accuracy than the reference mass-based emission measurement.