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Emissions from light duty vehicles have traditionally been measured using a chassis dynamometer, while heavy duty testing has been based on engine dynamometers. However, the need for in-use vehicle emissions data has led to the development of two transportable heavy duty chassis dynamometers capable of testing buses and heavy trucks. A test cycle has been developed for Class 8 trucks, which typically have unsyncronized transmissions. This test cycle has five peaks, each consisting of an acceleration, cruise period, and deceleration, with speeds and acceleration requirements that can be met by virtually all vehicles in common service. Termed the “WVU 5 peak truck test”, this 8 km (5 mile) cycle has been used to evaluate the emissions from diesel and ethanol powered over-the-road tractors and from diesel and ethanol powered snow plows, all with Detroit Diesel 6V92 engines.

A bi-fuel engine capable of operating either on compressed natural gas (CNG) or gasoline is being developed for the transition to alternative fuel usage. A Saturn 1.9 liter 4-cylinder engine was selected as a base powerplant. A control system that allows closed-loop optimization of both fuel delivery and spark timing was developed. Stock performance and emissions of the engine, as well as performance and emissions with the new controller on gasoline and CNG, have been documented. CNG operation in an engine designed for gasoline results in power loss because of the lower volumetric efficiency with gaseous fuel use, yet such an engine does not take advantage of the higher knock resistance of CNG. It is the goal of this research to use the knock resistance of CNG to recover the associated power loss. The two methods considered for this include turbocharging with a variable boost wastegate and raising the compression ratio while employing variable valve timing.

In order to obtain meaningful analyses of exhaust gas emissions and fuel economy for a heavy duty vehicle from a chassis dynamometer, the accurate simulation of road load characteristics is crucial. The adjusted amount of power to be absorbed by the chassis dynamometer during road driving of the tested vehicle needs to be calculated. In this paper, the performance of the chassis dynamometer under transient load cycle operations is discussed and the transient response of the power absorption system is presented. In addition, the design criteria of the chassis dynamometer used to test heavy duty vehicles under steady and transient load is described.

The Stiller-Smith mechanism is a new mechanism for the translation of linear motion into rotary motion, and has been considered as an alternative to the conventional slider-crank mechanism in the design of internal combustion engines and piston compressors. Piston motion differs between the two mechanisms, being perfectly sinusoidal for the Stiller-Smith case. Plots of dimensionless volume and volume rate-change are presented for one engine cycle. It is argued that the different motion is important when considering rate-based processes such as heat transfer to a cylinder wall and chemical kinetics during combustion. This paper also addresses the fact that a Stiller-Smith engine will be easier to configure for adiabatic operation, with many attendant benefits.

The paper captures the recent events in relation with the Volkswagen (VW) Emissions Scandal and addresses the impact of this event on the future of power train development. The paper analyses the impact on the perspectives of the internal combustion engine, the battery based electric car and the hydrogen based technology. The operation of the United States Environmental Protection Agency (EPA), VW and the United States prosecutor, sparked by the action of the International Council on Clean Transportation (ICCT) is forcing the Original Equipment Manufacturers (OEM) towards everything but rationale immediate transition to the battery based electric mobility. This transition voids the value of any improvement of the internal combustion engine (ICE), especially in the lean burn, compression ignition (CI) technology, and of a better hybridization of powertrains, both options that have much better short term perspectives than the battery based electric car.

Heavy-duty diesel engines (HDDE), because of their widespread use and reputation of expelling excessive soot, have frequently been held responsible for excessive amounts of overall environmental particulate matter (PM). PM is a considerable contributor to air pollution, and a subject of primary concern to health and regulatory agencies worldwide. The U.S. Environmental Protection Agency (EPA) has provided PM emissions regulations and standards of measurement techniques since the 1980's. PM standards set forth by the EPA for HDDEs are based only on total mass, instead of size and/or concentration. The European Union adopted a particle number emission limit, and it may influence the U.S. EPA to adopt particle number or size limits in the future. The purpose of this research was to study the effects biodiesel blended fuel and cetane improvers have on particle size and number.

An alternative fuel that has demonstrated considerable potential in reducing emissions and crude oil dependence is compressed natural gas (CNG). A dedicated CNG vehicle suffers from the lack of an adequate number of fueling stations and the poor range limited by CNG storage technology. A vehicle capable of operating on either gasoline or natural gas allows alternative fuel usage without sacrificing vehicle range and mobility. Although many such bi-fuel vehicles are in existence, historically they have employed older engine designs and made compromises in engine control parameters that can degrade performance relative to gasoline and increase emissions. A modern production engine, a 1992 Saturn 1.9 liter 16 valve powerplant, is being optimized for operation on each fuel to realize the full potential of CNG in a bi-fuel system. CNG operation in an engine designed for gasoline typically suffers from reduced power, due in part to displacement of air by gaseous fuel.

Growing concern over ground-level ozone and its role in smog formation has resulted in extensive investigation into identifying ozone sources. Motor vehicle exhaust, specifically oxides of nitrogen and hydrocarbons, have been identified as major ozone precursors in urban areas. Past research has concentrated on assessing the impact of emissions from gasoline fueled light duty vehicles. However, little work has been done on identifying ozone precursors from medium and heavy duty diesel fueled vehicles. This paper presents the results of testing performed on a Navistar T 444E 190 horsepower diesel engine which is certified as a light/heavy-duty emissions classification and is used in medium duty trucks up to 11,800 kg (26,000 lb) GVW. Regulated emissions and speciated hydrocarbon emissions were collected using a filter, bag and Tenax adsorption cartridges for both steady state and transient engine operation.

An electrochemical cell is presented which reduces NOx emissions from a vehicle fueled by dedicated natural gas. The cell is comprised of a honeycomb shaped ceramic which is chemically coated with an electrically conductive material in two distinct regions which serve as electrodes such that, with the application of a voltage potential, a cathode and anode are formed. As the exhaust gas flows through the inner channels of the cell, the electrochemical reduction of NOx at the cathode yields nitrogen gas and oxide ions. The nitrogen continues to flow through the cell while the oxide ions dissolve in the solid electrolyte. At the anodic zone, oxide ions are converted to oxygen gas. The pressure drop across the cell was experimentally measured to insure that the back pressure created by the cell does not create a significant reduction in the efficiency of the engine.

Selective Catalytic Reduction (SCR), using urea injection, is being examined as a method for substantial reduction of oxides of nitrogen (NOx) for diesel engines, but the urea injection rates must be controlled to match the NOx production which may need to be predicted during open loop control. Unfortunately NOx is usually measured in the laboratory using a full-scale dilution tunnel and chemiluminescent analyzer, which cause delay and diffusion (in time) of the true manifold NOx concentration. Similarly, delay and diffusion of measurements of all emissions cause the task of creating instantaneous emissions models for vehicle simulations more difficult. Data were obtained to relate injections of carbon dioxide (CO2) into a tunnel with analyzer measurements. The analyzer response was found to match a gamma distribution of the input pulse, so that the analyzer output could be modeled from the tunnel CO2 input.

Relationships between diesel particulate matter (PM) mass and gaseous emissions mass produced by engines have been explored to determine whether any gaseous species may be used as surrogates to infer PM quantitatively. It was recognized that sulfur content of fuel might independently influence PM mass, since PM historically is composed of elemental carbon, organic carbon, sulfuric acid, ash and wear particles. Previous research has suggested that PM may be correlated with carbon monoxide (CO) for an engine that is exercised through a variety of speed and load cycles, but that the correlation does not extend to a group of engines. Large databases from the E-55/59 and Gasoline/Diesel PM Split programs were employed, along with the IBIS bus emissions database and several additional data sets for on- and off-road engines to examine possible relationships.

Concern over dwindling oil supplies has led to the adoption of alternate fuels to power fleet vehicles. However, during the interim period when alternate fuel supply stations are few and far between, dual fuel engines prove a necessity. In the light duty arena, these engines are typically gasoline engines modified to accommodate compressed natural gas (CNG) as an alternate fuel, but they are seldom optimized with both fuels in mind. A Saturn 1.9 liter 4 cylinder dual overhead cam engine was selected as a base for developing an optimized gasoline/CNG powerplant. Baseline data on power and steady state emissions (CO2, CO, NOx, HC) were found using the standard Saturn controller. In addition to monitoring standard sensor measurements, real-time pressure traces were taken for up to 256 cycles using a modified head with embedded PCB piezoelectric pressure transducers.

Further growth of diesel engines in the light-duty and heavy-duty vehicular market is closely linked to the potential health risks of diesel exhaust. The California Air Resources Board and the Office of Environmental Health Hazard Assessment have identified diesel exhaust as a toxic air contaminant. The International Agency for Research on Cancer concluded that diesel particulate is a probable human carcinogen [1]. Cleaner burning liquid fuels, such as those derived from natural gas via the Fischer-Tropsch (FT) process, offer a potentially economically viable alternative to standard diesel fuel while providing reduced particulate emissions. Further understanding of FT operation may be realized by investigating the differences in toxicity and potential health effects between particulate matter(PM) derived from FT fuel and that derived from standard Federal diesel No. 2 (DF).

Concern over atmospheric pollution has led to the development of testing procedures to evaluate the hydrocarbon, carbon dioxide, carbon monoxide and oxides of nitrogen emissions from internal combustion engines. In order to perform emissions testing on vehicles, a chassis dynamometer capable of simulating expected driving conditions must be employed. West Virginia University has developed a Heavy Duty Transportable Emissions Testing Laboratory to perform chassis testing on trucks and buses. Emissions from the vehicle are monitored and recorded over the duration of a testing schedule. Usually the vehicle emissions from the whole test are reported as mass of emissions per unit distance driven. However, there is interest in relating the instantaneous emissions to the immediate conditions at specific points in the test, and in determining the emissions for discrete segments of the test (modal analysis).

Heavy duty tractor-trailers under freeway operations consume about 65% of the total engine shaft energy to overcome aerodynamic drag force. Vehicles are exposed to on-road crosswinds which cause change in pressure distribution with a relative wind speed and yaw angle. The objective of this study was to analyze the drag losses as a function of on-road wind conditions, on-road vehicle position and trajectory. Using coefficient of drag (CD) data available from a study conducted at NASA Ames, Geographical Information Systems model, time-varying weather data and road data, a generic model was built to identify the yaw angles and the relative magnitude of wind speed on a given route over a given time period. A region-based analysis was conducted for a study on interstate trucking operation by employing I-79 running through West Virginia as a case study by initiating a run starting at 12am, 03/03/2012 out to 12am, 03/05/2012.

The recent oil crisis has once again emphasized the need to develop both fuel efficient engines and alternately fueled engines, particularly for automotive applications. Engines which burn coal or coal pyrolysis products are attractive, but ignition delay and metal erosion problems continue to limit high speed operation of such engines. Further, the throttled spark ignition engine often used with methanol and natural gas does not prove an efficient or tolerant device for the combustion of a wide range of fuel. Therefore, an novel approach must be taken in order to achieve the efficient and flexible operation of such an engine. A novel design of a fuel tolerant engine suitable for burning coal fuels separates the combustion from the piston in order to have more careful flame control and to exclude the particulate matter from the engine's piston rings.

The emissions reduction benefits of Fischer-Tropsch (FT) diesel fuel have been shown in several recent published studies in both engine testing and in-use vehicle testing. FT diesel fuel shows significant advantages in reducing regulated engine emissions over conventional diesel fuel primarily to: its zero sulfur specification, implying reduced particulate matter (PM) emissions, its relatively lower aromaticity, and its relatively high cetane rating. However, the actual effect of FT diesel formulation on the in-cylinder combustion characteristics of unmodified modern heavy-duty diesel engines is not well documented. As a result, a Navistar T444E (V8, 7.3 liter) engine, instrumented for in-cylinder pressure measurement, was installed on an engine dynamometer and subjected to steady-state emissions measurement using both conventional Federal low sulfur pump diesel and a natural gas-derived FT fuel.

A novel engine concept, currently under study, addresses many of the problems commonly associated with conventional internal combustion engines. In its simplest form the novel engine consists of a single crankshaft operating both a piston compressor and a piston expander which are connected by a continuous flame combustion chamber. One might regard this as a Brayton piston engine which is similar to a previous engine investigated by Warren. Also, due to the use of piston cylinders as the compression and expansion devices, this engine varies little mechanically from current engine technology thus allowing for easy implementation. The main improvement from conventional engine design is that the expansion cylinder can have a larger displacement than that of the compression cylinder. This allows more power to be extracted by lowering the loss due to blowdown and this will increase the thermal efficiency.

A research program at West Virginia University sought to identify and quantify the individual hydrocarbon species present in alternative fuel exhaust. Compressed natural gas (CNG) has been one of the most widely researched fuels proposed to replace liquid petroleum fuels. Regulated CNG non-methane hydrocarbon emissions are often lower than hydrocarbon emissions from conventional liquid fuels because of the absence of heavier hydrocarbons in the fuel. Reducing NOx and non-methane organic gas (NMOG) emission levels reduces the ozone forming potential (OFP) of the exhaust gases. A Hercules GTA 3.7 liter medium duty CNG engine was operated at seven load and speed set points using local supply CNG gas. The engine was operated at several rated, intermediate and idle speed set points. The engine was operated while the air/fuel ratio value was varied.

Diesel Particulate Filters (DPFs) are well assessed exhaust aftertreatment devices currently equipping almost every modern diesel engine to comply with the most stringent emission standards. However, an accurate estimation of soot content (loading) is critical to managing the regeneration of DPFs in order to attain optimal behavior of the whole engine-after-treatment assembly, and minimize fuel consumption. Real-time models can be used to address challenges posed by advanced control systems, such as the integration of the DPF with the engine or other critical aftertreatment components or to develop model-based OBD sensors. One of the major hurdles in such applications is the accurate estimation of engine Particulate Matter (PM) emissions as a function of time. Such data would be required as input data for any kind of accurate models. The most accurate way consists of employing soot sensors to gather the real transient soot emissions signal, which will serve as an input to the model.