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It has been long established fact that fuel economy is a key driving force of low viscosity gasoline engine oil research and development considered by the original equipment manufacturers (OEMs) and lubricant companies. The development of low viscosity gasoline engine oils should not only focus on fuel economy improvement, but also on the low speed pre-ignition (LSPI) prevention property. In previous LSPI prevention literatures, the necessity of applying Ca/Mg-based detergents system in the engine oil formulations was proposed. In this paper, we adopted a specific Group III base oil containing Ca-salicylate detergent, borated dispersant, Mo-DTC in the formulation and investigated the various effects of Mg-salicylate and Mg-sulfonate on the performance of engine oil. It was found that Mg-sulfonate showed a significant detrimental impact on silicone rubber compatibility while the influence from Mg-salicylate remains acceptable.

A 10 KWe dual-mode space power system concept has been identified which is based on INEL's Small Externally-fueled Heat Pipe Thermionic Reactor (SEHPTR) concept. This power system will enhance user capabilities by providing reliable electric power and by providing two propulsion systems; electric power for an arc-jet electric propulsion system and direct thrust by heating hydrogen propellant inside the reactor. The low thrust electric thrusters allow efficient station keeping and long-term maneuvering. The direct thrust capability can provide tens of pounds of thrust at a specific impulse of around 730 seconds for maneuvers that must be performed more rapidly. The direct thrust allows the nuclear power system to move a payload from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO) in less than one month using approximately half the propellant of a cryogenic chemical stage.

THIS paper deals with the road-test portion of the extensive efforts made during 1937 by the Cooperative Fuel Research Committee to get as precise a correlation as possible between the laboratory knock ratings of automobile fuels and their corresponding ratings in cars on the road. It is anticipated that the comprehensive results of car tests reported here, taken together with the results of the laboratory rating program reported in the companion paper, will serve as the basis of the continuing studies aimed at developing the best possible correlation between road and laboratory knock ratings. Work similar to that reported here has been conducted concurrently in England by the Institution of Petroleum Technologists, using British cars and fuels. An exchange of information between the British and American groups working on this problem is being made.

THE 1940 CFR Road Tests have developed new information that can be used for the development of fuels and engines. Application of the principles worked out in these tests is expected to result in a more efficient utilization of fuel antiknock properties and more effective engine design and adjustment to meet the requisites of current motor fuels. These tests indicate that the ASTM octane number alone, or even a road octane number as determined by methods heretofore widely used, does not give sufficient information for present needs relative to fuel behavior in service. Neither do test methods previously used provide sufficient information concerning the fuel requirements and knocking characteristics of engines. The new methods of approach which have been developed furnish needed information relative to the fuel and engine relationship that heretofore has been obscure, and indicate paths for future developments.

The cooperative road tests carried out during 1941 have added considerable information and experience to that already existing on the subject of road detonation testing. Extensive data were obtained on the fuel requirements of the 1940 and 1941 models of the three most popular cars. Corresponding data were obtained on the knocking characteristics of current gasolines representing the bulk of the sales volume in various parts of the United States. On account of large variations in octane-number requirement among different cars of the same make - due to differences in ignition timing, combustion-chamber deposit, and other causes - and on account of variations in commercial gasolines, it has been necessary to use statistical methods of analysis in the appraisal of fuel and engine relationships. These methods of analysis have been applied in a number of ways, and have proved very useful.

The paper presents a combined experimental and numerical investigation of a small unit displacement two-stroke SI engine operated with gasoline and Natural Gas (CNG). A detailed multi-cycle 3D-CFD analysis of the scavenging process is at first performed in order to accurately characterize the engine behavior in terms of scavenging patterns and efficiency. Detailed CFD analyses are used to accurately model the complex set of physical and chemical processes and to properly estimate the fluid-dynamic behavior of the engine, where boundary conditions are provided by a in-house developed 1D model of the whole engine. It is in fact widely recognized that for two-stroke crankcase scavenged, carbureted engines the scavenging patterns (fuel short-circuiting, residual gas distribution, pointwise lambda field, etc.) plays a fundamental role on both of engine performance and tailpipe emissions.

Three-dimensional transient simulation was performed and an autoignition model was implemented to predict knock occurrence and autoignition site in a heavy-duty liquefied petroleum gas (LPG) engine. A flame area evolution (FAE) premixed combustion model was applied to simulate flame propagation. Engine experiments using a single-cylinder research engine were performed to calibrate the reduced kinetic model and to verify the result of this modeling. A pressure transducer and a head-gasket type ion-probe circuit board were installed to detect knock occurrence, flame arrival angle, and autoignition site. The simulation result shows good agreement with engine experiments. It also provides much information about in-cylinder phenomena and some ways to reduce knocking tendency. This knock simulation can be used as a development tool of engine design.

With growing concern about global warming, alternatives to fossil fuels in internal combustion engines are searched. In this context, hydrogen is one of the most interesting fuels as it shows excellent combustion properties such as laminar flame speed and energy density. In this work a CFD methodology for 3D-CFD in-cylinder simulations of engine combustion is proposed and its predictive capabilities are validated against test-bench data from a direct injection spark-ignition (DISI) prototype. The original engine is a naturally aspirated, single cylinder compression ignition (Diesel fueled) unit. It is modified substituting the Diesel injector with a spark plug, adding two direct gas injectors, and lowering the compression ratio to run with hydrogen fuel. A 3D-CFD model is built, embedding in-house developed ignition and heat transfer models besides G-equation one for combustion.

A 3D-CFD model with detailed chemical kinetics was developed to investigate the combustion characteristics of HCCI engines, especially those fueled with hydrogen and n-heptane. The effects of changes in some of the key important variables that included compression ratio and chamber surface temperature on the combustion processes were investigated. Particular attention was given, while using a finer 3-D mesh, to the development of combustion within the chamber crevices between the piston top-land and cylinder wall. It is shown that changes in the combustion chamber wall surface temperature values influence greatly the autoignition timing and location of its first occurrence within the chamber. With high chamber wall temperatures, autoignition takes place first at regions near the cylinder wall while with low surface temperatures; autoignition takes place closer to the central region of the mixture charge.

THIS paper analyzes ignition-delay data and knocking characteristics of fuels. An approach to the problems of fuel sensitivity and engine severity has been made by attempting to relate the properties of the fuel-air mixture as shown from ignition-delay data and the temperatures and pressures reached by the compressed gases in an engine. The relation between octane numbers and ignition-delay characteristics of the fuels is examined. Antiknock properties of tel are investigated. It is shown that the amount of antiknock effectiveness is related to the amount of tel decomposed.

Through an addition of a small amount of hydrogen to the main fuel, combustion process can be considerably enhanced in internal combustion engines producing significantly lower levels of exhaust emissions. This improvement in combustion can be mainly attributed to the faster and cleaner burning characteristics of hydrogen in comparison to conventional liquid and gaseous fuels. An oxygen-enrichment of a fuel-air mixture also improves thermal efficiency and reduces especially particulate, carbon monoxide and unburned hydrocarbon emissions in exhaust. This contribution describes the results of experimental investigation where a small amount of hydrogen and oxygen is produced by Hydrogen Generating System through the electrical dissociation of water and are added to the intake of a compression ignition engine operating on a commercial diesel fuel. It is shown that level of exhaust emissions including NOx can be moderately reduced using such a pre-treatment method in diesel engines.

Knock in Spark Ignited (SI) engines has received significant research attention historically since this phenomenon effectively restricts the compression ratio and hence the thermal efficiency of the engine. The latent heat of vaporization (LHV) of a fuel affects its knock resistance in production engines as well as affecting its Research Octane Number (RON) rating. The reason for this is that evaporative cooling of the fuel lowers in-cylinder gas temperatures resulting in reduced tendency for end-gas auto-ignition. Controlling of the fuel-air mixture temperature to 422 K at the inlet port as per the Motor Octane Number (MON) test method ensures full evaporation of the liquid fuel, and hence LHV is assumed to have little effect during this procedure. LHV therefore has a strong influence on a fuel's Octane Sensitivity (OS) - the difference between its RON and MON values.

For fuelling road transportation in the future, particularly light-duty vehicles, there has been much speculation about the use of hydrogen and fuel cells to provide electrical power to an all-electric drive train. An alternative powertrain would use a simple battery to store electricity directly, using power from the electrical grid to charge the battery when the vehicle is not in use. The energy efficiency of these two different approaches has been compared, using a complete “energy conversion chain analysis”. The successful development and introduction into the marketplace of grid-connected hybrid vehicles could eliminate the need for road vehicles to use petroleum fuels, at least for the majority of miles traveled. If electricity were to be generated primarily from sustainable primary energy sources, then road transportation would also become sustainable, resulting in an “Electricity Economy”, rather than a “Hydrogen Economy.

This paper reports the results of an exhaust emissions characterization from the non-catalyst control systems employed on the Mazda RX-4 rotary, the Honda CVCC, and the Chrysler electronic lean burn. Throughout the paper, exhaust emissions from these vehicles are compared to those from a Chrysler equipped with an oxidation catalyst and an air pump. The emissions characterized are carbon monoxide, hydrocarbons, nitrogen oxides, sulfur dioxide, sulfates, hydrogen sulfide, carbonyl sulfide, hydrogen cyanide, aldehydes, particulate matter, and detailed hydrocarbons. A brief description of the sampling and analysis procedures used is included within the discussion.

As mission length and the number and complexity of payload experiments increase, so does the probability of thermodegradation contingencies (e.g. fire, chemical release and/or smoke from overheated components or burning materials), which could affect mission success. When a thermodegradation event occurs on board a spacecraft, potentially hazardous levels of toxic gases could be released into the internal atmosphere. Experiences on board the Space Shuttle have clearly demonstrated the possibility of small thermodegradation events occurring during even relatively short missions. This paper will describe the Combustion Products Analyzer (CPA), which is being developed under the direction of the Toxicology Laboratory at Johnson Space Center to provide necessary data on air quality in the Shuttle following a thermodegradation incident.

This paper quantifies the potential of electric propulsion systems to reduce petroleum use and greenhouse gas (GHG) emissions in the 2030 U.S. light-duty vehicle fleet. The propulsion systems under consideration include gasoline hybrid-electric vehicles (HEVs), plug-in hybrid vehicles (PHEVs), fuel-cell hybrid vehicles (FCVs), and battery-electric vehicles (BEVs). The performance and cost of key enabling technologies were extrapolated over a 25-30 year time horizon. These results were integrated with software simulations to model vehicle performance and tank-to-wheel energy consumption. Well-to-wheel energy and GHG emissions of future vehicle technologies were estimated by integrating the vehicle technology evaluation with assessments of different fuel pathways. The results show that, if vehicle size and performance remain constant at present-day levels, these electric propulsion systems can reduce or eliminate the transport sector's reliance on petroleum.

In this paper, a number of issues of concern in relation to hybrid electric vehicles (HEVs) and fuel cell vehicles (FCVs) are discussed and comparatively reviewed. Currently, almost all the activities in the development of new generation of vehicles are focused on FCVs and HEVs. However, there are still uncertainties as to which provides the maximum benefits in terms of performance, energy savings, impact on environment etc. In particular, potential control strategies for FCVs and HEVs will be discussed and compared. For FCVs, these include power-averaging control as well as control based on maximum conversion efficiency, among others. HEV control strategies include electrically peaking hybrid propulsion, and parameter optimization approaches such as battery SOC maximization, emissions minimization, and optimal power management.

Engine knock is a major challenge that limits the achievement of higher engine efficiency by increasing the compression ratio of the engine. To address this issue, using a higher octane number fuel can be a potential solution to reduce or eliminate the propensity for knock and so obtain better engine performance. Methanol, a promising alternative fuel, can be produced from conventional and non-conventional energy resources, which can help reduce pollutant emissions. Methanol has a higher octane number than typically gasolines, which makes it a viable option for reducing knock intensity. This study compared the combustion characteristics of gasoline and methanol fuels in an optical spark-ignition engine using multiple spark plugs. The experiment was carried out on a single-cylinder four-stroke optical engine. The researchers used a customized metal liner with four circumferential spark plugs to generate multiple flame kernels inside the combustion chamber.

Different methods to improve the performance of a WCO (waste cooking oil of sunflower) based mono cylinder compression ignition (CI) engine were investigated. Initially WCO was converted into its emulsion by emulsification process and tested as fuel. In the second phase, the engine intake system was modified to admit excess oxygen along with air to test the engine with WCO and WCO emulsion as fuels under oxygen enriched environment. In the third phase, the engine was modified to work in the dual fuel mode with hydrogen being used as the inducted fuel and either WCO or WCO emulsion used as the pilot fuel. All the tests were carried out at 100% and 40% of the maximum load (3.7 kW power output) at the rated speed of 1500 rpm. Engine data with neat diesel and neat WCO were used for comparison. WCO emulsion indicated considerable improvement in performance. The smoke and NOx values were noted to be less than neat WCO.

Combustion with knock is an abnormal phenomenon which constrains the engine performance, thermal efficiency and longevity. The advance timing of the ignition system requires it to be updated with respect to fuel octane number variation. The production series engines are calibrated by the manufacturer to run with a special fuel octane number. In the experiment, the engine was operated at different speeds, loads, spark advance timings and consumed commercial gasoline with research octane numbers (RON) 95, 97 and 100. A 1-dimensional validated engine combustion model was run in the GT-Power software to simulate the engine conditions required to define the knock envelope at the same engine operation conditions as experiment. The knock intensity investigation due to spark advance sweep shows that combustion with noise was started after a specific advance ignition timing and the audible knock occur by increasing the advance timing.