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A system was designed for controlling fuel injection and ignition timing for use on a port fuel injected, gas-fueled engine. Inputs required for the system include manifold absolute pressure, manifold air temperature, a once per revolution crankshaft pulse, a once per cycle camshaft pulse, and a relative encoder pulse train to determine crank angle. A prototype card installed in the computer contains counters and discrete logic which control the timing of ignition and injection events. High current drivers used to control the fuel injector solenoids and coil primary current are optically isolated from the computer by the use of fiber optic cables. The programming is done in QuickBASIC running in real time on a 25 MHz 80486 personal computer. The system was used to control a gas-fueled spark ignition engine at various conditions to map the torque versus air-fuel ratio and ignition timing. Each surface was mapped for a given fuel flow and speed.

This paper summarizes the state-of-the-art of various alternative fuel technologies for heavy-duty transit applications and compares them to conventional and “ clean” diesel engines. Alternative powerplants considered include compressed natural gas (CNG), liquefied natural gas (LNG), methanol, ethanol, liquefied petroleum gas (LPG), hydrogen, and several electric technologies. The various technologies are ranked according to emissions, operating and capital costs, safety, development status, driveability, and long term fuel supply. A simple spreadsheet-based rating system is presented; it not only provides a versatile, semi-quantitative way to rank technologies using both quantitative and qualitative information, but also helps identify critical areas which limit implementation for a given application. An example is given for urban transit buses.

The focus of this research is on the development of a more energy efficient shortened liquid cooling/warming garment (LCWG) based on physiological principles comparing the efficacy of heat transfer of different body zones; the capability of blood to deliver heat; individual muscle and fat body composition as a basis for individual thermal profiles to customize the zonal involvement of the garment; and the development of shunts to minimize or redirect the cooling/warming loop for different environmental conditions, physical activity levels, and emergency situations. The total length of tubing in the LCWG is approximately 35% less, and the weight decreased by 45% compared to the LCVG currently used in space.

Diesel fuel injection systems are operating at increasingly higher pressure (up to 250 MPa) with smaller clearances, making them more sensitive to diesel fuel contaminants. Most liquid particle counters have difficulty detecting particles <4 μm in diameter and are unable to distinguish between solid and semi-solid materials. The low conductivity of diesel fuel limits the use of the Coulter counter. This raises the need for a new method to characterize small (<4 μm) fuel contaminants. We propose and evaluate an aerosolization method for characterizing solid particulate matter in diesel fuel that can detect particles as small as 0.5 μm. The particle sizing and concentration performance of the method were calibrated and validated by the use of seed particles added to filtered diesel fuel. A size dependent correction method was developed to account for the preferential atomization and subsequent aerosol conditioning processes to obtain the liquid-borne particle concentration.

In many operating regimes, exhaust gas recirculation (EGR) while maintaining MBT spark timing improves cycle efficiency in SI engines. As the level of exhaust dilution is increased, the flame speed is reduced and the combustion rate is impaired. This leads to a drop in fuel economy as EGR rates are increased beyond the optimal level. To take advantage of the efficiency benefit of EGR without incurring the penalties of late combustion, a sensor which detects late combustion is tested. The signal from an ionization sensor placed near the exhaust port has been found to correlate to combustion which continues late into the expansion stroke. It may be possible to use the output from the ion sensor to maintain the EGR at the the optimum for fuel economy.

Cruise control is one of the most critical issues that manufacturers concern about. But last many researches just focused on engine side control with general step transmission. Continuously Variable Transmissions (CVT) can cover a wide range of ratios continuously. This makes it possible to operate a combustion engine in more efficient working points than stepped transmission. With this merit, fuel optimal cruise control by CVT ratio control is possible with precise longitudinal dynamic model. Estimation of longitudinal load such as road slope and rolling resistance is essential for precise cruise control of automotive vehicle. In this paper, using model based road slope estimation method with gravity sensor, precise longitudinal dynamic model of automotive vehicle is presented. Real-time adaptive algorithm is also implemented for detecting external driving condition change and compensating bias of g-sensor.

Exhaust particulate emissions from a 4-cylinder, 2.25 liter spark ignition engine were measured and characterized. A single-stage ejector-diluter system was used to dilute and cool the exhaust sample for measurement. The particulate measurement equipment included a condensation nucleus counter and a scanning mobility particle sizer. Exhaust measurements were made both upstream and downstream of the catalytic converter using three different fuels. Unlike particulate emissions in diesel engines, spark ignition exhaust particle emissions were found to be highly unstable. Typically, a stable “baseline” concentration on the order of 105 particles/cm3 is emitted. Occasionally, however, a “spike” in the exhaust particle concentration is observed. The exhaust particle concentrations observed during these spikes can increase by as much as two orders of magnitude over the baseline concentration.

The correlations between the physical properties and autoignition parameters of several alternate fuels have been examined. The fuels are DF-2 and its blends with petroleum derived fuels, coal derived fuels, shale derived fuels, high aromatic naphtha sun-flower oils, methanol and ethanol. A total of eighteen existing correlations are discussed. An emphasis is made on the suitability of each of the correlations for the development of electronic controls for diesel engines when run on alternate fuels. A new correlation has been developed between the cetane number of the fuels and its kinematic viscosity and specific gravity.

Extended range electric vehicles (EREVs) are a potential solution for fossil fuel usage mitigation and on-road emissions reduction. The use of EREVs can be shown to yield significant fuel economy improvements when proper energy management strategies (EMSs) are employed. However, many in-use EREVs achieve only moderate fuel reduction compared to conventional vehicles due to the fact that their EMS is far from optimal. This paper focuses on in-use rule-based EMSs to improve the fuel efficiency of EREV last-mile delivery vehicles equipped with two-way Vehicle-to-Could (V2C) connectivity. The method uses previous vehicle data collected on actual delivery routes and machine learning methods to improve the fuel economy of future routes. The paper first introduces the main challenges of the project, such as inherent uncertainty in human driver behavior and in the roadway environment. Then, the framework of our practical physics-model guided data-driven approach is introduced.

A key challenge for the practical introduction of dual-fuel reactivity controlled compression ignition (RCCI) combustion modes in diesel engines is the requirement to store two fuels on-board. This work demonstrates that partially reforming diesel fuel into less reactive products is a promising method to allow RCCI to be implemented with a single stored fuel. Experiments were conducted using a thermally integrated reforming reactor in a reformed exhaust gas recirculation (R-EGR) configuration to achieve RCCI combustion using a light-duty diesel engine. The engine was operated at a low engine load and two reformed fuel percentages over ranges of exhaust gas recirculation (EGR) rate and main diesel fuel injection timing. Results show that RCCI-like emissions of NOx and soot were achieved load using the R-EGR configuration. It was also shown that complete fuel conversion in the reforming reactor is not necessary to achieve sufficiently low fuel reactivity for RCCI combustion.

Exhaust particle number concentrations and size distributions were measured from the exhaust of a 1995 direct injection, Diesel engine. Number concentrations ranged from 1 to 7.5×107 particles/cm3. The number size distributions were bimodal and log-normal in form with a nuclei mode in the 7-15 nm diameter range and an accumulation mode in the 30-40 nm range. For nearly all operating conditions, more than 50% of the particle number, but less than 1% of the particle mass were found in the nuclei mode. Preliminary indications are that the nuclei mode particles are solid and formed from volatilization and subsequent nucleation of metallic ash from lubricating oil additives. Modern low emission engines produce low concentrations of soot agglomerates. The absence of these agglomerates to act as sites for adsorption or condensation of volatile materials makes nucleation and high number emissions more likely.

Alcohols are examined as supplemental carbureted fuels for highspeed turbocharged diesels as typified by the White Motor/Waukesha F310 DBLT (6 cylinder, 310 cu. in.). Most of the work was with methanol; ethanol and isopropanol were compared at a few points. Fumigation (dual-fueling) with alcohol significantly reduced smoke and intake manifold temperature. These effects were largest at high load. Efficiency and HC emissions were essentially unchanged. Cylinder pressures and rise rates were examined for possible adverse effects on engine structure. The range of speed and load favorable to alcohol dual-fueling are such that, should alcohols become economically competitive as fuels, a practical duel-fuel system could be applied to existing diesel engines.

The impact of compression ratio on engine efficiency is well known. A plethora of mechanical concepts have been proposed for altering engine compression ratio in real time. Some of these, like free-piston configurations or complex crank-slider mechanisms have the added ability to alter piston trajectory along with compression ratio. This secondary modality raises the question: Is there a more optimal piston position versus crank-angle profile for spark-ignition (SI) engines than the near-sinusoidal motion produced by a traditional four-bar crank-slider mechanism? Very little published literature directly addresses this question. This work presents the results of a quasi-dimensional SI engine model using piston trajectory as an input. Specific trajectory traits including increased dwell at top dead center and asymmetric compression and expansion strokes were swept. The trajectory also was optimized using a single objective genetic algorithm with 60 individuals and 40 generations.

As part of an ongoing program to control the emissions of diesel-powered equipment used in underground mines, the U. S. Bureau of Mines evaluated exhaust emissions from a compression ignition engine using oxygenated diesel fuels and a diesel oxidation catalyst (DOC). The fuels include neat (100%) soy methyl ester (SME), and a blend of 30% SME (by volume) with 70% petroleum diesel fuel. A Caterpillar 3304 PCNA engine was tested for approximately 50 hours on each fuel. Compared with commercial low-sulfur diesel fuel (D2), neat SME increased volatile organic diesel particulate matter (DPM) but greatly decreased non-volatile DPM, for a net decrease in total DPM. The DOC further reduced volatile and total DPM NOx emissions were slightly reduced for the case of neat SME, but otherwise were not significantly affected. Peak brake power decreased 9% and brake specific fuel consumption increased 13 to 14% for the neat methyl soyate because of its lower energy content compared with D2.

A 1.9 liter Volkswagen TDI engine has been modified to accomodate the addition of hydrogen into the intake manifold via timed port fuel injection. Engine out particulate matter and the emissions of oxides of nitrogen were investigated. Two fuels,low sulfur diesel fuel (BP50) and soy methyl ester (SME) biodiesel (B99), were tested with supplemental hydrogen fueling. Three test conditions were selected to represent a range of engine operating modes. The tests were executed at 20, 40, and 60 % rated load with a constant engine speed o 1700 RPM. At each test condition the percentage of power from hydrogen energy was varied from 0 to 40 %. This corresponds to hydrogen flow rates ranging from 7 to 85 liters per minute. Particulate matter (PM) emissions were measured using a scaning mobility particle sizer (SMPS) and a two stage micro dilution system. Oxides of nitrogen were also monitored.

In-cylinder reforming of injected fuel during an auxiliary negative valve overlap (NVO) period can be used to optimize main-cycle auto-ignition phasing for low-load Low-Temperature Gasoline Combustion (LTGC), where highly dilute mixtures can lead to poor combustion stability. When mixed with fresh intake charge and fuel, these reformate streams can alter overall charge reactivity characteristics. The central issue remains large parasitic heat losses from the retention and compression of hot exhaust gases along with modest pumping losses that result from mixing hot NVO-period gases with the cooler intake charge. Accurate determination of total cycle energy utilization is complicated by the fact that NVO-period retained fuel energy is consumed during the subsequent main combustion period. For the present study, a full-cycle energy analysis was performed for a single-cylinder research engine undergoing LTGC with varying NVO auxiliary fueling rates and injection timing.

Previously, the authors have proposed a novel strategy called trajectory based combustion control for the free piston engine (FPE) where the shape of the piston trajectory between top and bottom dead centers is used as a control input to modulate the chemical kinetics of the fuel-air mixture inside the combustion chamber. It has been shown that in case of a hydraulic free piston engine (HFPE), using active motion control, the piston inside the combustion chamber can be forced to track any desired trajectory, despite the absence of a crankshaft, providing reliable starting and stable operation. This allows the use of optimized piston trajectory for every operating point which minimizes fuel consumption and emissions. In this work, this concept is extended to an electrical free piston engine (EFPE) as a modular power source.

Diesel exhaust particle number concentrations and size distributions, as well as gaseous and particulate mass emissions, were measured during steady-state tests on a US heavy-duty engine and a European passenger car engine. Two fuels were compared, namely a Fischer-Tropsch diesel fuel manufactured from natural gas, and a US D2 on-highway diesel fuel. With both engines, the Fischer-Tropsch fuel showed a considerable reduction in the number of particles formed by nucleation, when compared with the D2 fuel. At most test modes, particle number emissions were dominated by nucleation mode particles. Consequently, there were generally large reductions (up to 93%) in the total particle number emissions with the Fischer-Tropsch fuel. It is thought that the most probable cause for the reduction in nucleation mode particles is the negligible sulphur content of the Fischer-Tropsch fuel. In general, there were also reductions in all the regulated emissions with the Fischer-Tropsch fuel.

Experiments were performed to measure the average and time-resolved particle number emissions and number-weighted particle size distributions from a gasoline direct injection (GDI) engine. Measurements were made on a late model vehicle equipped with a direct injection spark ignition engine. The vehicle was placed on a chassis dynamometer, which was used to load the engine to road load at five different vehicle speeds ranging from 13 - 90 km/hr. Particle number emissions were measured using a TSI 3020 condensation nucleus counter, and size distributions were measured using a TSI 3934 scanning mobility particle sizer. Average polydisperse number concentration was found to increase from 1.1 × 108 particles/cm3 at 13 km/hr to 2.8 × 108 particles/cm3 at 70 km/hr. Under a closed-loop, stoichiometric homogeneous charge operating mode at 90 km/hr, number emissions fell to 9.3 × 107 particles/cm3 (at all other operating conditions, the engine was in a lean stratified charge operating mode).

The function of the engine air cleaning filter is to remove the particulate matter in the intake air to protect the engine and its components from wear and contamination. For a specific filter, the efficiency is a function of the size of the particles being collected and the air flow velocity through the filter. Traditional tests of engine air cleaners are based on the use of specific test dusts, such as the AC Coarse and AC Fine, to determine the mass collection efficiency. However, they do not provide information on the size dependent performance of the filters, and the variation in filter performance under different particle challenge conditions. The use of a fractional efficiency test method will help to provide this missing information. The purpose of this paper is to describe a fractional efficiency test system that has been designed to evaluate the fractional cleaning efficiency of engine air cleaning filters in the size range between 0.3 and 10 mm particle diameter.