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The growing presence of Spark Ignition Direct Injection (SIDI) engines along with the prevalence of direct injected Compression Ignition (CI) engines results in the requirement of Particulate Matter (PM) exhaust abatement. This occurs through the implementation of Gasoline Particulate Filters (GPFs) and Diesel Particulate Filters (DPFs). Modeling of GPFs and DPFs are analogous because of the similar flow patterns and wall flow PM capture methodology. Conventional modeling techniques include a two-channel (inlet/outlet) formulation that is applicable up to three-dimensions. However, the numerical stiffness that results from the need to couple the solution of these channels in compressible flow can result in relatively long run times. Previously, the author presented a lumped DPF model using dynamically incompressible flow intended for an Engine Control Unit (ECU) in order to generate a model that runs faster than real time using a high-level programming language.

In-cylinder engine modeling is a necessary aspect of combustion research. In particular, simulating heat release connects variable combustion behavior to fuel properties through the 1st Law of Thermodynamics. One extension of such models is to evaluate changes to in-cylinder behavior using the Second Law of Thermodynamics in order to identify the peak period of availability for work extraction. Thus, Second Law models are a useful tool to augment research into alternative fuel usage and optimization. These models also help identify internal irreversibilities that are separate from heat transfer and exhaust gas losses. This study utilizes a multi-zone 1st and 2nd Law Heat Release model to characterize the changes in combustion behavior of a number of neat fuels used in a single-cylinder compression ignition (CI) engine.

Engine manufacturers are considering the implementation of thermodynamic cycles for Waste Heat Recovery (WHR) in order to increase Internal Combustion Engine (ICE) system thermal efficiency. For these secondary cycles, the literature illustrates the preference of Organic Rankine Cycles (ORC's) due to its simplicity and efficient recovery of the medium grade waste heat found in engine exhaust. This paper simulates the heat recovery capacity of eight dry fluids (butane, pentane, hexane, cyclopentane, benzene, toluene, R245fa, and R123) for an ORC based on the exhaust from a single-cylinder diesel engine-generator operating under five different loading conditions. The model, developed using REFPROP and the Matlab Optimization Toolbox, represents the physical components using isentropic pump and expander efficiencies, along with two-zone heat exchangers. All fluids present cycle efficiencies between 10-15%, with the heaviest hydrocarbons generating the largest amount of work.

Particulate filters (PF) are a highly effective after-treatment device that reduces particulate matter emissions, a rising environmental concern in the automotive industry. However, accumulation of solid particles during the PF filtration process increases engine backpressure considerably, which can have a negative impact on engine efficiency, acoustics, and gaseous emissions. In this area, an accurate pressure drop model helps to better understand the effect of accumulated solid particles in the PF on engine backpressure, aiding in design and regeneration considerations without physical testing. These effects are further improved on board the vehicle using a single equation pressure drop model with a relatively low computational cost. This article presents a thorough history of PF pressure drop models and their advancements.

With the rapid growth of biodiesel production, it is prudent to research ways to improve its operation and performance in an engine, especially concerning fuel economy and exhaust emissions. This requires a thorough understanding of both the biodiesel production and engine operating processes. Completion of a published study of the impact of biodiesel fuel properties on engine operation indicated that it is difficult to draw conclusions about the exact causes of increased NOx emissions with respect to biodiesel properties without the capability of measuring engine cylinder pressures. As improvements were made to the authors' laboratory, a system to monitor and record pressure inside a diesel engine during operation was constructed to test dissimilar fuels. In the current work, three different fuels were tested in order to investigate combustion phasing, emissions, and fuel consumption as a function of fuel properties such as density, viscosity, Cetane Number, and energy content.

This study investigates the practicality of vehicle coast down testing as a suitable replacement to moving floor wind tunnel experimentation. The recent implementation of full-scale moving floor wind tunnels is forcing a re-estimation of previous coefficient of drag determinations. Moreover, these wind tunnels are relatively expensive to build and operate and may not capture concepts such as linear and quadratic velocity dependency along with the influence of tire pressure on rolling resistance. As a result, the method elucidated here improves the accuracy of the fundamental vehicle modeling equations while remaining relatively affordable. The trends produced by incorporating on road test data into the model fit the values indicated by laboratory tests. This research chose equipment based on a balance between affordability and accuracy while illustrating that higher resolution frequency equipment would further enhance the model accuracy.

In this paper, the available correlations proposed in the literature for the gas-side heat transfer in the intake and exhaust system of a spark-ignition internal combustion engine were surveyed. It was noticed that these only by empirically fitted constants. This similarity provided the impetus for the authors to explore if a universal correlation could be developed. Based on a scaling approach using microscales of turbulence, the authors have fixed the exponential factor on the Reynolds number and thus reduced the number of adjustable coefficients to just one; the latter can be determined from a least squares curve-fit of available experimental data. Using intake and exhaust side data, it was shown that the universal correlation The correlation coefficient of this proposed heat transfer model with all available experimental data is 0.845 for the intake side and 0.800 for the exhaust side.

Biodiesel is a potential alternative to Ultra Low Sulfur Diesel (ULSD); however, it often suffers from increased fuel consumption in comparison to ULSD when injection timings and/or pressures are similar. To decrease fuel consumption, increasing biodiesel injection pressure has been found to mitigate the issues associated with its relatively high viscosity and lower energy content. When doing so, the literature indicates decreased emissions, albeit with potentially greater nitrogen oxide (NOx) emissions in contrast to ULSD. In order to better understand the trade-off between fuel consumption and NOx emissions, this study explores the influence of fuel injection pressure on ULSD, Waste Cooking Oil (WCO) biodiesel, and their blends in a single-cylinder compression ignition (CI) engine. In particular, fuel injection pressures and timings for WCO biodiesel and blended fuels are adjusted to attempt to mimic the in-cylinder pressure profile of operation using ULSD.

The use of Compressed Natural Gas (CNG) has demonstrated the potential to decrease Particulate Matter (PM) and nitrogen oxide (NOx) emissions simultaneously when used in a dual-fuel application with diesel fuel functioning as the ignition source. However, some authors do find that NOx emissions can increase. One postulation is that the conflicting results in the literature may be due to the difference in composition of natural gas around the world. Therefore, in order to investigate if CNG composition influences combustion performance and emissions, four unique mixtures of CNG were tested (i.e., 87% to 96% methane) while minimizing the combined difference of the density, heating value, and constant pressure specific heat of each mixture. This was accomplished at moderate energy substitution ratios (up to 40%) in a single cylinder engine operating at various loads.

Diesel knock and ringing combustion in compression ignition (CI) engines are largely an unavoidable phenomenon and are partially related to the overall effectiveness of the fuel injection process. Modern electronic fuel injection systems have been effective at reducing the intensity of knock in CI engines, largely through optimization of fuel injection timing, as well as higher operating pressures that promote enhanced fuel and air mixing. In this effort, a single-cylinder CI engine was tested under a number of different combustion strategies, including a comparison of mechanical and electronic injection systems, increasing fuel injection pressures for biodiesel fuels, and the usage of dual-fuel combustion with compressed natural gas (CNG). Using in-cylinder pressure traces and engine operational data, the difference in injection mechanisms, fuel preparation, and their effects on knock intensity is clearly illustrated.

Utilizing a higher compression ratio in a Compression Ignition (CI) engine grants an obvious advantage of improved thermal efficiency. However, the resulting combustion temperatures promote dissociation ensuing in increased nitrogen oxide (NOx) emissions. Unfortunately, due to the inherent properties of CI combustion, it is difficult to achieve simultaneous reduction of NOx and particulate matter (PM) through conventional combustion methods. Taking a different route though accomplishing Homogeneous Charge Compression Ignition (HCCI) in CI engines will largely eliminate NOx and PM; however, combustion can result in a significant increase in hydrocarbon (HC) and carbon monoxide (CO) emissions due to the low volatility of diesel fuel. Hence, this work attempts another avenue of Low Temperature Combustion (LTC) by employing Pre-mixed Charge Compression Ignition (PCI) combustion on a comparatively higher compression ratio (21.2) single cylinder CI engine.

Transportation surveys illustrate that one of the most significant deterrents to bicycles as a form of conveyance is the concern with safety. Moreover, crash statistics also indicate that motor vehicles pose a severe risk to bicycles. As a result, this paper focuses on the development of a bicycle-mounted traffic monitoring system with the potential of providing early crash warnings to bicyclists. The system designed has a low monetary cost ($280.84) and is small enough to mount on a bicycle (94 mm × 56 mm × 89 mm). Moreover, it has sufficient range to track cars before they get dangerously close to the bike. The foundation of the system includes a Light Detection and Ranging (LIDAR) module that includes direct compatibility with microcontrollers. This LIDAR module interacts with a camera, stepper motor, and small computers through interfacing hardware and software. While robust, one limitation of the system is processing power.

The recent increase in natural gas availability has made compressed natural gas (CNG) an option for fueling the transportation sector of the United States economy. In particular, CNG is advantageous in dual-fuel operation alongside ultra low sulfur diesel (ULSD) for compression ignition (CI) engines. This work investigates the usage of natural gas mixtures at varying Energy Substitution Rates (ESRs) within a high compression ratio single-cylinder CI engine, including performance and heat release modeling of dual-fuel combustion. Results demonstrate the differing behavior of utilizing CNG at various substitution rates.

Selective Catalytic Reduction (SCR) catalysts used in Lean NOx Trap (LNT) - SCR exhaust aftertreatment systems typically encounter alternating oxidizing and reducing environments. Reducing conditions occur when diesel fuel is injected upstream of a reformer catalyst, generating high concentrations of hydrogen (H₂), carbon monoxide (CO), and hydrocarbons to deNOx the LNT. In this study, the functionality of an iron (Fe) zeolite SCR catalyst is explored with a bench top reactor during steady-state and cyclic transient SCR operation. Experiments to characterize the effect of an LNT deNOx event on SCR operation show that adding H₂ or CO only slightly changes SCR behavior with the primary contribution being an enhancement of nitrogen dioxide (NO₂) decomposition into nitric oxide (NO). Exposure of the catalyst to C₃H₆ (a surrogate for an actual exhaust HC mixture) leads to a significant decrease in NOx reduction capabilities of the catalyst.

The modeling of emitted hydrocarbons from internal combustion engines for exhaust aftertreatment devices has remained relatively unchanged since the early 1970s. This older model subdivides the hydrocarbon species into fast, slow, and non-oxidizing components. Current and future regulations from the United States Environmental Protection Agency stretch the abilities of this methodology, necessitating the need for more advanced modeling techniques. To this end, this paper provides a review on the different groups of hydrocarbons in order to provide background and contextual information on the different species expected in diesel emissions. Additionally, this work groups these species into different categories, depending on their chemical make-up, impact on human health, reactivity in the environment, and their prevalence within diesel emissions.

Software packages including Argonne National Lab's Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model and the EPA's Motor Vehicle Emissions Simulation (MOVES) model are useful in analyzing the emission profiles of light-duty vehicles. In particular, GREET performs a detailed life cycle fuel energy and emissions analysis, while MOVES focuses on energy and emissions during vehicle operation. This study uses MOVES2010b in the creation of emission trends in order to predict future emissions regulations and the subsequent aftertreatment device areas of improvement required to meet these standards. A second objective was to create four time sheet tables in order to update the base vehicle operation emission profiles used in GREET. The simulation results depict the balance between nitrous oxide and hydrocarbon emissions, the dependency upon climate effects, and areas for potential improvement given recent engine design trends.

As climate change drives the exploration into new and alternative fuels, biodiesel has emerged as a promising alternative to traditional diesel fuel. To further increase the viability of biodiesel, a unique system at the University of Kansas utilizes glycerin, the primary byproduct of biodiesel production, for power generation. This system converts glycerin into a hydrogen-rich gas (syngas) that is sent to an engine-generator system in one continuous flow process. The current setup allows for running the engine-generator system on pure propane, reformed propane, or reformed glycerin, with each fuel serving a unique purpose. This paper discusses upgrades in pure propane operation that serves the intent of preheating the engine prior to syngas operation and establishing the baseline energy requirement for fueling the system.

Given the need of the automotive industry to improve fuel efficiency, many companies are moving towards lean burn and low temperature combustion regimes. Critical control of these methods requires an accurate Exhaust Gas Recirculation (EGR) system that can maintain its desired rate and temperature. In this area, the literature illustrates different methodologies to control and monitor this EGR system; however, it lacks a discussion of how the non-linear nature of wave dynamics and time responses of an engine must be taken into account. In order to perform research into the use of EGR for these combustion regimes, an automated, closed-loop EGR system that uses a microprocessor to compute the slope change of the EGR rate and temperature as part of its feedback algorithm was constructed for use in a teaching and research laboratory. The findings illustrate that the system works as intended by replicating known combustion trends with EGR.

The growth of hydraulic fracking has resulted in a dramatic cost reduction of Compressed Natural Gas (CNG), a low carbon fuel. CNG cannot be used as singular fuel in conventional Compression Ignition (CI) engines because of its high auto-ignition characteristics. However, CNG-assisted diesel combustion represents a means to shift the energy consumption of CI engines away from liquid fossil fuels. Calculation of the rate of heat release is vital for understanding and optimizing this mode of engine operation. A previously constructed three-zone equilibrium heat release model that is calibrated to engine exhaust emission measurements was augmented in order to allow for the addition of CNG in the engine intake. The model was also adapted to permit reuse of unburned CNG gas with other exhaust species via exhaust gas recirculation. This is because experiments demonstrated a potentially significant increase in methane emissions under high CNG flowrates.

Recently, ozone addition has come under scrutiny as a means of controlling ignition timing for Low Temperature (LTC) combustion, which defeats the NOx-PM tradeoff using a highly dilute, homogeneous mixture. This is because ozone decomposes into atomic oxygen and hydroxyl radicals that influence the early phases of the ignition delay process. In order to understand ozone's influence on combustion better, this work analyzes the effects of ozone-assisted combustion for a single-cylinder, direct-injection Compression Ignition engine via a mechanical pump-line-nozzle fuel system and an electronically controlled common-rail fuel injection system. Experimental outcomes indicate a relatively small influence of ozone for the mechanical injection system with a comparably decreased effect for the common rail system.