Matt Miyasato

Fuel Property, Emission Test, and Operability Results from a Fleet of Class 6 Vehicles Operating on Gas-to-Liquid Fuel and Catalyzed Diesel Particle Filters

A fleet of six 2001 International Class 6 trucks operating in southern California was selected for an operability and emissions study using gas-to-liquid (GTL) fuel and catalyzed diesel particle filters (CDPF). Three vehicles were fueled with CARB specification diesel fuel and no emission control devices (current technology), and three vehicles were fueled with GTL fuel and retrofit with Johnson Mattheys CCRT diesel particulate filter. No engine modifications were made.

Emission Rates of Regulated Pollutants from Current Technology Heavy-Duty Diesel and Natural Gas Goods Movement Vehicles

Chassis dynamometer emissions testing of 11 heavy-duty goods movement vehicles, including diesel, natural gas, and dual-fuel technology, compliant with US-EPA 2010 emissions standard were conducted. Results of the study show that three-way catalyst (TWC) equipped stoichiometric natural gas vehicles emit 96% lower NOx emissions as compared to selective catalytic reduction (SCR) equipped diesel vehicles. Characteristics of drayage truck vocation, represented by the near-dock and local drayage driving cycles, were linked to high NOx emissions from diesel vehicles equipped with a SCR. Exhaust gas temperatures below 250 °C, for more than 95% duration of the local and near-dock driving cycles, resulted in minimal SCR activity. The low percentage of activity SCR over the local and near-dock cycles contributed to a brake-specific NOx emissions that were 5-7 times higher than in-use certification limit. The study also illustrated the differences between emissions rate measured from chassis dynamometer testing and prediction from the EMFAC model. The results of the study emphasize the need for model inputs relative to SCR performance as a function of driving cycle and engine operation characteristics.

Achievement of Low Emissions by Engine Modification to Utilize Gas-to-Liquid Fuel and Advanced Emission Controls on a Class 8 Truck

A 2002 Cummins ISM engine was modified to be optimized for operation on gas-to-liquid (GTL) fuel and advanced emission control devices. The engine modifications included increased exhaust gas recirculation (EGR), decreased compression ratio, and reshaped piston and bowl configuration.

Introduction and Perspectives

Combustion processes operating under fuel lean conditions can have very low emissions and very high efficiency. Pollutant emissions are reduced because flame temperatures are low. In addition, for hydrocarbon combustion, when leaning is accomplished with excess air, complete burnout of fuel generally results, reducing hydrocarbon and carbon monoxide emissions. Achieving these improvements and meeting the demands of practical combustion systems are complicated by low reaction rates, extinction, instabilities, mild heat release, and sensitivity to mixing. This first and introductory chapter introduces the concept of lean conditions broadly; it provides specific examples from mobile and stationary sources on how lean combustion technology is driven by regulatory concerns, and it provides a highlight preview of the remaining chapters of the volume. With the complexity, breadth, and dynamic nature of the lean combustion field, it is impossible for any book to claim a complete state-of-the-art representation. Rather, we have tried to provide a foundation for lean combustion discussion and understanding across a range of technologies.

Chapter 1 – Introduction and Perspectives

Publisher Summary Studies of lean combustion are among the oldest in the combustion literature because its extreme represents the lean limit of inflammability, which has been a well-recognized hazard marker from the inception of combustion science. Lean combustion was considered only with regard to explosion hazards until the late 1950s, when lean flames were introduced as useful diagnostic tools for identifying detailed reaction behavior. This chapter presents the foundations of lean combustion including the roles of turbulence, flame front instabilities, and flame speed in controlling the robustness of the reaction. Lean combustion is employed in nearly all combustion technology sectors, including gas turbines, boilers, furnaces, and internal combustion (IC) engines. This wide range of applications attempts to take advantage of the fact that combustion processes operating under fuel lean conditions can have very low emissions and very high efficiency. Pollutant emissions are reduced because flame temperatures are typically low, reducing thermal nitric oxide formation. In addition, for hydrocarbon combustion, when leaning is accomplished with excess air, complete burnout of fuel generally results, reducing hydrocarbon and carbon monoxide (CO) emissions. Unfortunately, achieving these improvements and meeting the demands of practical combustion systems is complicated by low reaction rates, extinction, instabilities, mild heat release, and sensitivity to mixing.

Emissions of Transport Refrigeration Units with CARB Diesel, Gas-to-Liquid Diesel and Emissions Control Devices

A novel in situ method was used to measure emissions and fuel consumption of transport refrigeration units (TRUs). The test matrix included two fuels, two exhaust configurations, and two TRU engine operating speeds. Test fuels were California ultra low sulfur diesel and gas-to-liquid (GTL) diesel. Exhaust configurations were a stock muffler and a Thermo King pDPF diesel particulate filter. The TRU engine operating speeds were high and low, controlled by the TRU user interface. Results indicate that GTL diesel fuel reduces all regulated emissions at high and low engine speeds. Application of a Thermo King pDPF reduced regulated emissions, sometimes almost entirely. The application of both GTL diesel and a Thermo King pDPF reduced regulated emissions at high engine speed, but showed an increase in oxides of nitrogen at low engine speed.

Determination of Optimal Engine Parameters for Exhaust Emissions Reduction Using the Taguchi Method

In order to meet the ever more stringent exhaust emissions regulations and improve fuel consumption, heavy-duty Diesel engines (HDDE) have been equipped with electronically controlled components, including Exhaust Gas Recirculation systems (EGR), Variable Geometry Turbochargers (VGT) and advanced Fuel Injection Equipment (FIE) allowing for more flexible engine optimization. The introduction of such components increased the number of parameters influencing the optimization procedure; thus, significantly increasing the required amount of test-cell time to achieve an optimal engine calibration. Moreover, the adoption of aftertreatment systems, such as Selective Catalytic Reduction (SCR) technology or Diesel Particulate Filter (DPF) systems, required to comply with latest US-2010 and EURO V emissions legislations, requires flexible engine calibrations to address their efficiency dependency upon the thermodynamic conditions of the engine exhaust. The primary objective of this study was to develop and implement a simple multivariate optimization technique to program any given engine with multiple calibrations, both for steady-state and transient conditions, capable of modifying exhaust properties in order to guarantee optimal aftertreatment efficiencies during a wide range of engine operation. Four engine parameters, each at three levels, were selected for the optimization process, namely, EGR rate, VGT position, Start of Injection (SOI) and Nozzle Opening Pressure (NOP) as a surrogate for fuel injection pressure. Changes in control parameters which lead to an improvement in one specific emissions component may however often result in the deterioration of another. Thus, a good understanding of the relationship between individual control parameter effects is of utmost importance to correctly attain the optimum condition in short time and simultaneously reduce the number of experiments to be performed. Therefore, Design of Experiment (DOE) via factorial design, using the Taguchi method, was adopted to simultaneously study multiple factors and isolate the effects of changes in a single engine parameter on exhaust emissions. Different engine calibrations were obtained for an 11-liter Volvo engine by performing a set of only nine experiments for each engine speed/load point, which were selected to be equally distributed underneath the engine’s lug-curve. The main engine calibrations proved to be test cycle independent since comparable emission levels were observed over the European Steady-State Cycle (ESC) as well as the Federal Test Procedure (FTP). Reductions in Oxides of Nitrogen (NOx ) on the order of 20% were achieved, while limiting the fuel consumption penalty to below 3%. Several high-efficiency calibrations were generated, achieving fuel consumption reductions close to 6%. Thus, the Taguchi method was found to be a viable way for simultaneous optimization of key engine parameters leading to a significant reduction in test-cell time; hence, relative development costs.Copyright

Development of an Advanced Retrofit Aftertreatment System Targeting Toxic Air Contaminants and Particulate Matter Emissions From HD-CNG Engines

Increasing urban pollution levels have led to the imposition of evermore stringent emissions regulations on heavy-duty engines used in transit buses. This has made compressed natural gas (CNG) a promising fuel for reducing emissions, particularly particulate matter (PM) from heavy-duty transit buses. Indeed, research studies performed at West Virginia University (WVU) and elsewhere have shown that pre-2010 compliant natural gas engines emit an order of magnitude lower PM emissions, on a mass basis, when compared to diesel engines without any exhaust aftertreatment devices. However, on a number basis, particle emissions in the nanoparticulate range were an order of magnitude higher for natural gas fueled buses than their diesel counterparts. There exists a significant number of pre-2007 CNG powered buses in transit agencies in the US and elsewhere in the world. Therefore, an exhaust aftertreatment device was designed and developed by WVU, in association with Lubrizol, to retrofit urban transit buses powered by MY2000 Cummins Westport C8.3G+ heavy-duty CNG engines, and effectively reduce Toxic Air Contaminants (TAC) and PM (mass and number count) exhaust emissions. The speciation results showed that the new exhaust aftertreatment device reduced emissions of metallic elements such as iron, zinc, nonmetallic minerals such as calcium, phosphorus and sulfur derived from lube oil additives to non-detectable levels, which otherwise could contribute to an increase in number count of nanoparticles. The carbonyl compounds were reduced effectively by the oxidation catalyst to levels below what were found in the dilution air. Also, hydrocarbons identified as TAC’s by California Air Resource Board (CARB) [1] were reduced to non-detectable levels. This ultimately reduced the number of nanoparticles to levels equal to that found in the dilution air.Copyright