Timothy Theiss

Fuel Economy and Emissions of the Ethanol-Optimized Saab 9-5 Biopower

Saab Automobile recently released the BioPower engines, advertised to use increased turbocharger boost and spark advance on ethanol fuel to enhance performance. Specifications for the 2.0 liter turbocharged engine in the Saab 9-5 Biopower 2.0t report 150 hp (112 kW) on gasoline and a 20% increase to 180 hp (134 kW) on E85 (nominally 85% ethanol, 15% gasoline). While FFVs sold in the U.S. must be emissions certified on Federal Certification Gasoline as well as on E85, the European regulations only require certification on gasoline. Owing to renewed and growing interest in increased ethanol utilization in the U.S., a European-specification 2007 Saab 9-5 Biopower 2.0t was acquired by the Department of Energy and Oak Ridge National Laboratory (ORNL) for benchmark evaluations. Results show that the vehicle’s gasoline equivalent fuel economy on the Federal Test Procedure (FTP) and the Highway Fuel Economy Test (HFET) are on par with similar U.S.-legal flex-fuel vehicles. Regulated and unregulated emissions measurements on the FTP and the US06 aggressive driving test (part of the supplemental FTP) show that despite the lack of any certification testing requirement in Europe on E85 or on the U.S. cycles, the vehicle is within Tier 2, Bin 5 emissions levels (note that full useful life emissions have not been measured) on the FTP, and also within the 4000 mile (6400 km) US06 emissions limits. Emissions of hydrocarbon-based hazardous air pollutants are higher on Federal Certification Gasoline while ethanol and aldehyde emissions are higher on ethanol fuel. The advertised power increase on E85 was confirmed through acceleration tests on the chassis dynamometer as well as on-road.

Effects of Intermediate Ethanol Blends on Legacy Vehicles and Small Non-Road Engines, Report 1 - Updated

Intended for policymakers and others who make decisions about, and set guidelines for, the proper use of intermediate ethanol blends such as E20 in both vehicle engines and other engine types.

Compatibility of elastomers with test fuels of gasoline blended with ethanol

This article summarises the compatibility of six elastomers – used in fuel storage and delivery systems – with test fuels representing gasoline blended with up to 85% ethanol. Individual coupons were exposed to test fuels for four weeks to achieve saturation. The change in volume and hardness, when wetted and after drying, were measured and compared with the original condition.

Comparison of Prime Movers Suitable for USMC Expeditionary Power Sources

This report documents the results of the ORNL investigation into prime movers that would be desirable for the construction of a power system suitable for the United States Marine Corps (USMC) expeditionary forces under Operational Maneuvers From The Sea (OMFTS) doctrine. Discrete power levels of {approx}1, 5, 15, and 30 kW are considered. The only requirement is that the prime mover consumes diesel fuel. A brief description is given for the prime movers to describe their basic scientific foundations and relative advantages and disadvantages. A list of key attributes developed by ORNL has been weighted by the USMC to indicate the level of importance. A total of 14 different prime movers were scored by ORNL personnel in four size ranges (1,5, 15, & 30 kW) for their relative strength in each attribute area. The resulting weighted analysis was used to indicate which prime movers are likely to be suitable for USMC needs. No single engine or prime mover emerged as the clear-cut favorite but several engines scored as well or better than the diesel engine. At the higher load levels (15 & 30 kW), the results indicate that the open Brayton (gas turbine) is a relatively mature technology and likely a suitable choice to meet USMC needs. At the lower power levels, the situation is more difficult and the market alone is not likely to provide an optimum solution in the time frame desired (2010). Several prime movers should be considered for future developments and may be satisfactory; specifically, the Atkinson cycle, the open Brayton cycle (gas turbine), the 2-stroke diesel. The rotary diesel and the solid oxide fuel cell should be backup candidates. Of all these prime movers, the Atkinson cycle may well be the most suitable for this application but is an immature technology. Additional demonstrations of this engine will be conducted at ORNL. If this analysis is positive, then the performance of a generator set using this engine, the open Brayton and the 2-stroke diesel should be estimated to evaluate its potential suitability for expeditionary forces. The overriding conclusion of this effort is that we feel a suitable prime mover can be found but that the development will be technically challenging and trade-offs will be made before an optimum solution is found.

Superhydrophobic and superhydrophilic surface-enhanced separation performance of porous inorganic membranes for biomass-to-biofuel conversion applications

ABSTRACT A new class of porous membranes is introduced to provide unique separation mechanisms by surface interactions and capillary condensation. High-performance architectural surface selective (HiPAS) membranes were designed for high perm-selective flux and high-temperature tolerance for hot vapor processing and liquid processing. Due to surface-enhanced selectivity, larger-fluxes were achieved by utilizing larger pore sizes (~8 nm for vapor phase and micron-sized pores for liquid phase separations). This article describes a membrane-based separation concept for biomass conversion pathways and demonstrates the initial data for selective permeation of toluene–water and toluene–phenol–water relevant to biofuel processing.

An Approach for Investigating Adaptive Control Strategies to Improve Combustion Stability Under Dilute Operating Conditions

Dilute operation of internal combustion engines through lean fueling and/or high levels of exhaust gas recirculation (EGR) is frequently employed to increase fuel efficiency, reduce NOx emissions, and promote enhanced combustion modes such as HCCI. The maximum level of dilution is limited by the development of combustion instabilities that produce unacceptable levels of cycle-to-cycle combustion variability. These combustion instabilities are frequently stimulated by the nonlinear feedback associated with the residual and recirculated exhaust gases exchanged between successive cycles. However, with the application of adaptive control, it is possible to limit the severity of the combustion variability and regain efficiency and emission reduction benefits that would otherwise be lost. In order to better characterize the benefits of adaptive control, we have employed a two-zone phenomenological combustion model to simulate the onset of combustion instabilities under dilute operating conditions and illustrate the impact of these instabilities on emissions and fuel efficiency. The two-zone in-cylinder combustion model is coupled to a WAVE engine-simulation code, allowing rapid simulation of several hundred successive engine cycles with many external engine parametric effects included. By applying adaptive feedback control to the WAVE model, we demonstrate how mitigation of the extreme combustion events can result in improved efficiency and reduced emissions levels. We expect that this approach can be used to estimate the potential benefits of implementing adaptive control strategies on specific engine platforms to achieve further efficiency and emission-reduction gains.Copyright

Compatibility Assessment of Elastomer Materials to Test Fuels Representing Gasoline Blends Containing Ethanol and Isobutanol

The compatibility of elastomeric materials used in fuel storage and dispensing applications was determined for test fuels representing neat gasoline and gasoline blends containing 10 and 17 vol.% ethanol, and 16 and 24 vol.% isobutanol. The actual test fuel chemistries were based on the aggressive formulations described in SAE J1681 for oxygenated gasoline. Elastomer specimens of fluorocarbon, fluorosilicone, acrylonitrile rubber (NBR), polyurethane, neoprene, styrene butadiene rubber (SBR) and silicone were exposed to the test fuels for 4 weeks at 60°C. After measuring the wetted volume and hardness, the specimens were dried for 20 hours at 60°C and then remeasured for volume and hardness. Dynamic mechanical analysis (DMA) was also performed to determine the glass transition temperature (T g ). Comparison to the original values showed that all elastomer materials experienced volume expansion and softening when wetted by the test fuels. The fluorocarbons underwent the least amount of swelling ( 100%). The level of swelling for each elastomer was higher for the test fuels containing the alcohol additions. In general, ethanol produced slightly higher swell than the oxygen equivalent level of isobutanol. When dried, the fluorocarbon specimens were slightly swollen (relative to the baseline values) due to fuel retention. The NBRs and neoprene exhibited shrinkage and embrittlement associated with the extraction of plasticizers. SBR also experienced shrinkage (after drying) but its hardness returned to the baseline value. The dried volumes (and hardness values) of the silicone, SBR and fluorosilicone rubbers closely matched their original values, but the polyurethane specimen showed degradation with exposure to the test fuels containing ethanol or isobutanol. The DMA results showed that the test fuels effectively decreased T g for the fluorocarbons, but increased T g for the NBR materials. The T g values other elastomers were not affected by the test fuels.

Technical Issues Associated With the Use of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet

The Oak Ridge National Laboratory (ORNL) supports the U.S. Department of Energy (DOE) in assessing the impact of using intermediate ethanol blends (E10 to E30) in the legacy fleet of vehicles in the U.S. fleet. The purpose of this report is to: (1) identify the issues associated with intermediate ethanol blends with an emphasis on the end-use or vehicle impacts of increased ethanol levels; (2) assess the likely severity of the issues and whether they will become more severe with higher ethanol blend levels, or identify where the issue is most severe; (3) identify where gaps in knowledge exist and what might be required to fill those knowledge gaps; and (4) compile a current and complete bibliography of key references on intermediate ethanol blends. This effort is chiefly a critical review and assessment of available studies. Subject matter experts (authors and selected expert contacts) were consulted to help with interpretation and assessment. The scope of this report is limited to technical issues. Additional issues associated with consumer, vehicle manufacturer, and regulatory acceptance of ethanol blends greater than E10 are not considered. The key findings from this study are given.

Characterization and Mitigation of Spark Plug Electrode Erosion in Natural Gas and Automotive Engine Applications

Microstructural characterization was conducted for laboratory gasoline and natural gas reciprocating engine tested spark plug electrodes made from a range of model, developmental, and commercially available electrode alloys. These alloys were selected to explore the effects of differing electrode alloy thermal, chemical, and mechanical characteristics on erosion resistance, and were tested with and without sparking surface alloy insert pads (platinum group and novel Cr-based alloys). Extensive internal oxidation and cracking were observed in both gasoline and natural gas engine tests, indicative of an inherent degree of susceptibility of currently-used electrode materials when heated to elevated temperatures, no matter what the ignition conditions. Highly-alloyed heat-resistant alloys with excellent oxidation resistance in many high-temperature environments suffered from increased rates of erosion, as the gains in oxidation resistance appear to have been offset by hotter running temperatures resulting from decreased electrode alloy thermal conductivity. Promising early results were obtained with a novel Cr-6MgO-0.5Ti-0.3La2 O3 insert pad electrode alloy, investigated as an alternative to Pt- or Ir- base alloys, which showed little erosion and good resistance to cracking and oxidation.© 2007 ASME

Regulated and Unregulated Emissions From a Stoichiometric 250kW Natural Gas Engine

The emissions profile from a natural gas (NG) stationary power, stoichiometric, engine have been measured. Of particular interest are the unregulated emissions (especially formaldehyde) from this engine class. A relatively small 250 kW Caterpillar G3406 engine without a catalyst was used as the test platform with the emissions being characterized as a function of applied load and external conditions. In addition, multiple formaldehyde measurement techniques have been used and are compared. This paper presents the formaldehyde results, comparison of formaldehyde with various other parameters, a comparison of the different measurement techniques, and measurement of other toxic emissions from this engine.© 2004 ASME