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The accumulation of ash in a Diesel Particulate Filter (DPF) eventually results in an increase in the pressure drop across the exhaust system component. This situation translates into a reduced capacity for soot, and requires an increased frequency of active regenerations to eliminate this soot. For heavy duty diesel applications, the lifetime of the DPF is long enough to expect that cleaning of the ash from the DPF will be required. The physico-chemical characteristics of the ash as a function of temperature and time will have an impact on the effectiveness of this cleaning. To develop a deeper understanding of this subject, four different samples of ash were characterized in this study that were collected under active or passive regeneration from exhaust systems of engines running on different fuels: ultra low sulfur diesel (ULSD), and biodiesel fuels B20 and B100. The lubricant, an API CJ-4 oil, was used for each engine test.

A three phase catalytic mathematical model was developed for analysis and optimization of the volatile reactor assembly (VRA) used on International Space Station (ISS) Water Processor. The Langmuir-Hinshelwood Hougen-Watson (L-H) expression was used to describe the surface reaction rate. Small column experiments were used to determine the L-H rate parameters. The test components used in the experiments were acetic acid, acetone, ethanol, 1-propanol, 2-propanol and propionic acid. These compounds are the most prevalent ones found in the influent to the VRA reactor. The VRA model was able to predict performance of small column data and experimental data from the VRA flight experiment.

Water injection has been used to reduce the charge temperature and mitigate knocking due to its higher latent heat of vaporization compared to gasoline fuel. When water is injected into the intake manifold or into the cylinder, it evaporates by absorbing heat energy from the surrounding and results in charge cooling. However, the effect of detailed evaporation process on the combustion characteristics under gasoline direct injection relevant conditions still needs to be investigated. Therefore, spray study was firstly conducted using a multi-hole injector by injecting pure water and water-methanol mixture into constant volume combustion chamber (CVCC) at naturally aspirated and boosted engine conditions. The target water-fuel ratio was fixed at 0.5. Mie-scattering and schlieren images of sprays were analyzed to study spray characteristics, and evaluate the amount of water vaporization.

The effect of a Johnson Matthey catalyzed continuously regenerating technology™ (CCRT®) filter on the particle size distribution in the raw exhaust from a 2002 Cummins ISM-2002 heavy duty diesel engine (HDDE) is reported at four loads. A CCRT® (henceforth called DOC-CPF) has a diesel oxidation catalyst (DOC) upstream (UP) of a catalyzed particulate filter (CPF). The particle size data were taken at three locations of UP DOC, downstream (DN) DOC and DN CPF in the raw exhaust in order to study the individual effect of the DOC and the CPF of the DOC-CPF on the particle size distribution. The four loads of 20, 40, 60 and 75% loads at rated speed were chosen for this study. Emissions measurements were made in the raw exhaust chosen to study the effect of nitrogen dioxide and temperature on particulate matter (PM) oxidation in the CPF at different engine conditions, exhaust and carbonaceous particulate matter (CPM) flow rates.

Optical and laser diagnostics enable in-depth spray characterization in regards to macroscopic spray characteristics and in-situ fuel mixture quality information, which are needed in understanding the spray injection process and for spray model development, validation and calibration. Use of fuel surrogates in spray researches is beneficial in controlling fuel parameters, developing spray and combustion kinetic models, and performing laser diagnostics with known fluorescence characteristics. This study quantifies and evaluates the macroscopic spray characteristics of a single and multi-component surrogate in comparison to a gasoline with 10% ethanol under gasoline direct injection (GDI) engine conditions. In addition, the effect of fuel tracers on spray evolution and vaporization is also investigated. Both diethyl-methyl-amine/fluorobenzene as a laser-induced exciplex (LIEF) fluorescence tracer pair and 3-pentanone as a laser-induced fluorescence (LIF) tracer are examined.

The medium and heavy-duty powertrain industry trend is to reduce reliance on diesel fuel and is aligned with continued efforts of achieving ultra-low emissions and high brake efficiencies. Compression Ignition (CI) of late cycle Directly Injected (DI) Natural Gas (NG) shows the potential to match diesel performance in terms of brake efficiency and power density, with the benefit of utilizing a lower carbon content fuel. A primary challenge is to achieve stable ignition of directly injected NG over a wide engine speed and load range without the need for a separate ignition source. This project aims to demonstrate the CI of DI NG through experimental studies with a Single Cylinder Research Engine (SCRE), leading to the development of a mono-fueled NG engine with equivalent performance to that of current diesel technology, 25% lower CO2 emissions, and low engine out methane emissions.

Introducing water in a diesel engine has been known to decrease peak combustion temperatures and decrease NOx emissions. This however, has been limited to stationary and marine applications due to the requirement of a separate water supply tank in addition to the fuel tank, thereby a two-tank system. Combustion of hydrocarbon fuels produce between 1.35 (Diesel) and 2.55 times (Natural Gas) their mass in water. Techniques for extracting this water from the exhaust flow of an engine have been pursued by the United States department of defense (DOD) for quite some time, as they can potentially reduce the burden of supply of drinking water to front line troops in theater. Such a technology could also be of value to engine manufacturers as it could enable water injection for performance, efficiency and emissions benefits without the drawbacks of a two-tank system.

Gasoline knock resistance is characterized by the Research and Motor Octane Number (RON and MON), which are rated on the CFR octane rating engine at naturally aspirated conditions. However, modern automotive downsized boosted spark ignition (SI) engines generally operate at higher cylinder pressures and lower temperatures relative to the RON and MON tests. Using the naturally aspirated RON and MON ratings, the octane index (OI) characterizes the knock resistance of gasolines under boosted operation by linearly extrapolating into boosted “beyond RON” conditions via RON, MON, and a linear regression K factor. Using OI solely based on naturally aspirated RON and MON tests to extrapolate into boosted conditions can lead to significant errors in predicting boosted knock resistance between gasolines due to non-linear changes in autoignition and knocking characteristics with increasing pressure conditions.

A numerical investigation of a six-stroke direct injection compression ignition engine operation in a low temperature combustion (LTC) regime is presented. The fuel employed is a gasoline-like oxygenated fuel consisting of 90% isobutanol and 10% diethyl ether (DEE) by volume to match the reactivity of conventional gasoline with octane number 87. The computational simulations of the in-cylinder processes were performed using a high-fidelity multidimensional in-house 3D CFD code (MTU-MRNT) with improved spray-sub models and CHEMKIN library. The combustion chemistry was described using a two-component (isobutanol and DEE) fuel model whose oxidation pathways were given by a reaction mechanism with 177 species and 796 reactions.