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Technical Paper

A Next-Generation Emission Test Procedure for Small Utility Engines - Part 1, Background and Approach

1990-09-01
901595
Measurement of emissions from small utility engines has usually been accomplished using steady-state raw emissions procedures such as SAE Recommended Practice J1088. While raw exhaust measurements have the advantage of producing modal exhaust gas concentration data for design feedback; they are laborious, may influence both engine performance and the emissions themselves, and have no provision for concurrent particulate measurements. It is time to consider a full-dilution procedure similar in principle to automotive and heavy-duty on-highway emission measurement practice, leading to improvements in many of the areas noted above, and generally to much higher confidence in data obtained. When certification and audit of small engine emissions become a reality, a brief dilute exhaust procedure generating only the necessary data will be a tremendous advantage to both manufacturers and regulatory agencies.
Technical Paper

A Performance Comparison of Various Automatic Transmission Pumping Systems

1996-02-01
960424
The pumping system used in a step ratio automatic transmission can consume up to 20% of the total power required to operate a typical automotive transmission through the EPA city cycle. As such, it represents an area manufacturers have focused their efforts towards in their quest to obtain improved transmission efficiency. This paper will discuss the history of automatic transmission pumps that develop up to 300 psi along with a description of the factors used to size pumps and establish pump flow requirements. The various types of pumps used in current automatic transmissions will be described with a discussion of their characteristics including a comparison based upon observations of their performance. Specific attention will be focused on comparing the volumetric efficiency, mechanical efficiency, overall efficiency, pumping torque and discharge flow.
Technical Paper

Advanced Performance of Metallic Converter Systems Demonstrated on a Production V8 Engine

2002-03-04
2002-01-0347
It has been shown within the catalyst industry that the emission performance with higher cell density technology and therefore with higher specific geometric area is improved. The focus of this study was to compare the overall performance of high cell density catalysts, up to 1600cpsi, using a MY 2001 production vehicle with a 4.7ltr.V8 engine. The substrates were configured to be on the edge of the design capability. The goal was to develop cost optimized systems with similar emission and back pressure performance, which meet physical and production requirements. This paper will present the results of a preliminary computer simulation study and the final emission testing of a production vehicle. For the pre-evaluation a numerical simulation model was used to compare the light-off performance of different substrate designs in the cold start portion of the FTP test cycle.
Technical Paper

An Investigation of Sample Bag Hydrocarbon Emissions and Carbon Dioxide Permeation Properties

2004-03-08
2004-01-0593
The equipment for collecting dilute exhaust samples involves the use of bag materials (i.e., Tedlar®) that emit hydrocarbons that contaminate samples. This study identifies a list of materials and treatments to produce bags that reduce contamination. Based on the average emission rates, baked Tedlar®, Capran® treated with alumina deposition, supercritical CO2 extracted Kynar® and supercritical CO2 extracted Teflon NXT are capable of achieving the target hydrocarbon emission rate of less than 15 ppbC per 30 minutes. CO2 permeation tests were also performed. Tedlar, Capran, Kynar and Teflon NXT showed comparable average permeation rates. Based on the criteria of HC emission performance, changes in measured CO2 concentration, ease of sealing, and ease of surface treatment, none of the four materials could be distinguished from one another.
Technical Paper

Application of On-Highway Emissions Technology to a Backhoe

1992-04-01
920922
Recent legislation, including the California Clean Air Act of 1988 and the Federal Clean Air Act Amendment of 1990, includes off-road engines, equipment, and vehicles as targets for new exhaust emissions regulations. The Santa Barbara County Air Pollution Control District in cooperation with EXXON USA is conducting a major Low NOx Demonstration Program including mobile sources, construction equipment, and offshore equipment. As a part of this program, an existing backhoe has been retrofitted with a low NOx engine and demonstrated in the field. This paper discusses the work performed to allow Case model 580 backhoes to be retrofitted with Cummins 4BTAA3.9 on-highway turbocharged diesel engines. A standard production conversion kit can be used to mount the new engines in place of the older existing JI Case engines in some models while other newer models already have 4B3.9 engines. In addition, an air-to-air aftercooler and associated plumbing was designed and installed.
Journal Article

Automated Driving Impediments

2016-09-27
2016-01-8007
Since the turn of the millennium, automated vehicle technology has matured at an exponential rate, evolving from research largely funded and motivated by military and agricultural needs to a near-production market focused on everyday driving on public roads. Research and development has been conducted by a variety of entities ranging from universities to automotive manufacturers to technology firms demonstrating capabilities in both highway and urban environments. While this technology continues to show promise, corner cases, or situations outside the average driving environment, have emerged highlighting scenarios that impede the realization of full automation anywhere, anytime. This paper will review several of these corner cases and research deficiencies that need to be addressed for automated driving systems to be broadly deployed and trusted.
Technical Paper

Cetane Number Prediction from Proton-Type Distribution and Relative Hydrogen Population

1986-10-01
861521
A theoretical model for predicting cetane number of primary reference fuels from parameters measurable by proton nuclear magnetic resonance is presented. This modeling technique is expanded to include secondary reference fuels, pure hydrocarbons, and commercial-type fuels. An evaluation of the ignition process indicated that not only hydrogen type distribution measurable by proton NMR, but also relative hydrogen population is important in predicting cetane number. Two mathematical models are developed. One predicts cetane number of saturate fuels and the second predicts cetane number of fuels containing aromatic components. The aromatic fuel model is tested using the ASTM Diesel Check Fuels and shown to predict within the standard error of the model.
Technical Paper

Characterization of Particle Size Distribution of a Heavy-Duty Diesel Engine During FTP Transient Cycle Using ELPI

2000-06-19
2000-01-2001
Particle number concentrations and size distributions were measured for the diluted exhaust of a 1991 diesel engine during the US FTP transient cycle for heavy-duty diesel engines. The engine was operated on US 2-D on-highway diesel fuel. The particle measurement system consisted of a full flow dilution tunnel as the primary dilution stage, an air ejector pump as the secondary dilution stage, and an electrical low pressure impactor (ELPI) for particle size distribution measurements. Particle number emission rate was the highest during the Los Angeles Non Freeway (LANF) and the Los Angeles Freeway (LAF) segments of the transient cycle. However, on brake specific number basis the LAF had the lowest emission level. The particle size distribution was monomodal in shape with a mode between 0.084 μm and 0.14 μm. The shape of the size distribution suggested no presence of nanoparticles below the lower detection limit of the instrument (0.032 μm), except during engine idle.
Technical Paper

Comparative Emissions Performance of Sasol Fischer-Tropsch Diesel Fuel in Current and Older Technology Heavy-Duty Engines

2000-06-19
2000-01-1912
Comparative exhaust emission tests were performed with five diesel fuels, namely a Sasol Fischer-Tropsch diesel, a fuel meeting the CARB diesel fuel specification, a fuel meeting the US 2-D diesel fuel specification, and two blends of the Fischer-Tropsch diesel and the 2-D diesel. Hot-start and cold-start heavy-duty transient emission tests were performed using a 1999 model year DDC series 60 engine. Regulated exhaust emissions with the Fischer-Tropsch diesel were significantly lower than with the 2-D and CARB diesel fuels, in both the hot-start and cold-start tests. When compared with test results obtained previously with a 1991 engine, it was found that the reduction in NOX with the Fischer-Tropsch fuel was smaller in the 1999 engine, while the reduction in PM was greater.
Technical Paper

Comparison Between Real-Life Dust Samples and Standardized Test Dusts

1994-03-01
940322
Soil samples were collected from various geographical areas in the United States and Saudi Arabia. The samples were obtained from U.S. military installations at which off-road maneuvers are conducted. Saudi Arabia samples were obtained from the deserts surrounding Riyadh. The samples were characterized using particle size distributions, elemental analysis, mineral composition and particle angularity. Particle size distributions were determined for simulated fuel cells with intermittent and continual mixing. The results obtained from the world-wide soil sample analyses were compared against AC and PTI SAE fine and coarse test dust results.
Technical Paper

Comparison of Emissions and Fuel Economy Characteristics of Conventional, Additized, and Substantially Synthetic Diesel Fuels in a Heavy-Duty Diesel Engine

2002-05-06
2002-01-1702
This study compared four different candidate fuels which were prepared by blending different components with a typical No. 2 diesel. Two fuels were blended with a synthetic diesel prepared from natural gas condensate, and all candidate fuels were splash blended with a proprietary additive package from International Fuel Technology Inc. (IFT). These fuels were then compared to the No. 2 diesel and to a California Air Resources Board (CARB) equivalent diesel fuel. The comparisons included fuel properties such as sulfur content, aromatics, cetane, lubricity, distillation; emissions; and fuel consumption. Emission testing was conducted on a 1991 Detroit Diesel Series 60. The Environmental Protection Agency (EPA) transient cycle was utilized for emissions, fuel characterization was performed according to ASTM standards, and fuel consumption was calculated by the carbon balance method.
Technical Paper

Comparison of SCR Catalyst Performance on RMC SET Emission Cycle between an Engine and a High Flow Burner Rig

2013-04-08
2013-01-1070
Government agencies like EPA play an important role through regulation to reduce emissions and fuel consumption and to drive technological developments to reduce the environmental impact of burning petroleum fuels. Emissions testing and control is one of the leading and growing fields in the development of modern vehicles. Recently, Cummins Emissions Solutions (CES) and Southwest Research Institute (SwRI) worked jointly in order to achieve a method to conduct emissions testing efficiently and effectively. The collaborative work between the two organizations led to the usage of FOCAS HGTR™ (a diesel-based burner test rig at SwRI) to simulate the exhaust conditions generated by a 2010 ISX Cummins production engine operating over an EPA standard Ramped Modal Cycle Supplemental Emissions Test (RMC SET) cycle.
Technical Paper

Conversion of Two Small Utility Engines to LPG Fuel

1993-09-01
932447
Southwest Research Institute (SwRI) converted two small air-cooled, gasoline engines to operate on LPG (sometimes called propane since propane is LPG's major constituent). Typical two- and four-cycle engines were chosen for this investigation. The two-cycle engine used was a McCulloch string trimmer engine with 28 cc displacement. The four-cycle engine used was an L-head, Tecumseh TVS90 with 148 cc displacement. These are typical of engines found on lower cost lawn mowers and string trimmers. The engines were baseline tested on gasoline, converted to LPG, and tested to determine equivalence ratios at which the engines could be operated without exceeding manufacturers' recommended spark plug seat or exhaust temperatures. Engine startability and throttle response was maintained with the LPG conversion. The emissions of the four-cycle engine were measured following the CARB 6-mode emissions test procedure.
Journal Article

Design and Implementation of a D-EGR® Mixer for Improved Dilution and Reformate Distribution

2017-03-28
2017-01-0647
The Dedicated EGR (D-EGR®) engine has shown improved efficiency and emissions while minimizing the challenges of traditional cooled EGR. The concept combines the benefits of cooled EGR with additional improvements resulting from in-cylinder fuel reformation. The fuel reformation takes place in the dedicated cylinder, which is also responsible for producing the diluents for the engine (EGR). The D-EGR system does present its own set of challenges. Because only one out of four cylinders is providing all of the dilution and reformate for the engine, there are three “missing” EGR pulses and problems with EGR distribution to all 4 cylinders exist. In testing, distribution problems were realized which led to poor engine operation. To address these spatial and temporal mixing challenges, a distribution mixer was developed and tested which improved cylinder-to-cylinder and cycle-to-cycle variation of EGR rate through improved EGR distribution.
Technical Paper

Determination of Wear Index to Predict Fuel Filtration Performance

1999-03-01
1999-01-0003
The Beta ratio and filtration ratio are two common rating systems used to designate the abrasive filtration efficiency of fuel filters. Previous research developed a series of wear curves to predict the effects of abrasive particles of varying sizes on fuel injector performance. Based on this data, a formula was generated to predict injector wear based on the number of 5-, 10-, and 15-μm particles in the effluent. This value is called the wear index. (1,2)1 Various fuel filters with the same manufacturer rating were evaluated on a test engine to determine the wear index for each of these fuel filters. The results demonstrate the differences between these “similar” fuel filters and how the wear index provides additional information as compared to Beta and filtration ratios.
Technical Paper

Development and Validation of a Snowmobile Engine Emission Test Procedure

1998-09-14
982017
An appropriate test procedure, based on a duty cycle representative of real in-use operation, is an essential tool for characterizing engine emissions. A study has been performed to develop and validate a snowmobile engine test procedure for measurement of exhaust emissions. Real-time operating data collected from four instrumented snowmobiles were combined into a composite database for analysis and formulation of a snowmobile engine duty cycle. One snowmobile from each of four manufacturers (Arctic Cat, Polaris, Ski-Doo, and Yamaha) was included in the data collection process. Snowmobiles were driven over various on- and off-trail segments representing five driving styles: aggressive (trail), moderate (trail), double (trail with operator and one passenger), freestyle (off trail), and lake driving. Statistical analysis of this database was performed, and a five-mode steady-state snowmobile engine duty cycle was developed.
Technical Paper

Development of Low-Emissions Small Off-Road Engines

1999-09-28
1999-01-3302
The purpose of this project was to modify existing small off-road engines to meet ARB's originally proposed 1999 emissions standards. A particular point was to show that compliance could be attained without the need to redesign the base engines. Four high-sales volume, ARB-certified 1997 model engines were selected from the following categories: 1) handheld two-stroke engine, 2) handheld four-stroke engine, 3) non-handheld side-valve engine, and 4) a non-handheld overhead-valve engine. Engines were selected, procured, and baseline emission tested using applicable ARB test procedures. Appropriate emission control strategies were then selected and applied to the four engines. Emission reduction strategies used included air/fuel ratio optimization, and catalytic aftertreatment. Following the development of the four emission-controlled engines, final, certification-quality emissions tests were performed. All four engines met ARB's original 1999 Tier 2 emission standards after development.
Technical Paper

Development of a Methodology to Separate Thermal from Oil Aging of a Catalyst Using a Gasoline-Fueled Burner System

2003-03-03
2003-01-0663
Typically, an engine/dynamometer thermal aging cycle contains combinations of elevated catalyst inlet temperatures, chemical reaction-induced thermal excursions (simulating misfire events), and average air/fuel ratio's (AFR's) to create a condition that accelerates the aging of the test part. In theory, thermal aging is predominantly a function of the time at an exposure temperature. Therefore, if a burner system can be used to simulate the exhaust AFR and catalyst inlet and bed temperature profile generated by an engine running an accelerated aging cycle, then a catalyst should thermally age the same when exposed to either exhaust stream. This paper describes the results of a study that examined the aging difference between six like catalysts aged using the Rapid Aging Test (RAT) cycle (an accelerated thermal aging cycle). Three catalysts were aged using a gasoline-fueled engine aging stand; the other three were aged using a computer controlled burner system.
Journal Article

Development of a Synthetic Diesel Exhaust

2008-04-14
2008-01-0067
A two-phase study was performed to establish a standard diesel exhaust composition which could be used in the future development of light-duty diesel exhaust aftertreatment. In the first phase, a literature review created a database of diesel engine-out emissions. The database consisted chiefly of data from heavy-duty diesel engines; therefore, the need for an emission testing program for light- and medium-duty engines was identified. A second phase was conducted to provide additional light-duty vehicle emissions data from current technology vehicles. Engine-out diesel exhaust from four 2004 model light-duty vehicles with a variety of engine displacements was collected and analyzed. Each vehicle was evaluated using five steady-state engine operating conditions and two transient test cycles (the Federal Test Procedure and the US06). Regulated emissions were measured along with speciation of both volatile and semi-volatile components of the hydrocarbons.
Technical Paper

Development of a Transient Duty Cycle for Large Nonroad SI Engines

2002-05-06
2002-01-1716
The Environmental Protection Agency (EPA) has proposed emission standards for nonroad spark-ignition engines rated over 19 kW. Existing emission standards adopted by the California Air Resources Board require testing on a steady-state duty cycle. This paper presents the results of measurements to characterize normal operation from forklift trucks, which are the dominant application for these engines. In combination with previous measurements with a welder to represent constant-speed applications, the measured data were used to derive a composite 20-minute transient duty cycle for emission testing for all nonroad industrial spark-ignition engines.
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