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Procedure for Mapping Fuel Consumption for small spark ignited engines

The purpose of this SAE Standard is to provide a standardized test procedure for measuring the fuel consumption of spark ignited engines in the range of 225-999cc used in the consumer and commercial turf industry. The load points and associated fuel consumption rates will be measured as the engine operates on the engine speed governor, reflecting how the user will operate the equipment. The fuel consumption calculated in gallons of useage per hour will be derived from a specified engine speed and load map to be communicated universally to end users.
Technical Paper

New Test Procedures for Aircraft Piston Engine Oils

This paper covers the development of single cylinder engine tests for evaluating the new additive-type oils for aircraft piston engines. These procedures utilize the CLR Oil Test Engine. One procedure is designed to evaluate the high temperature oxidation stability of these oils, while the other measures their low temperature sludge dispersancy qualities.* *Both test methods are incorporated in the new Military Specification MIL-L-22851 (Wep), “Lubricating Oil, Aircraft Reciprocating Engine (ashless dispersant)” used for the procurement of the new additive type oils. The two procedures appear to be quite repeatable, and thus superior to any previous single cylinder engine tests used for evaluating aircraft engine oils. They were developed by Ethyl Corp. in a study sponsored by the Bureau of Naval Weapons of the U.S. Navy.
Technical Paper

An Inexpensive Method of Instrumenting Torsional Vibration

The use of conventional torsional vibration measuring equipment on single cylinder engines in the below 2 hp range is discussed. Disadvantages of this measuring equipment are outlined. Since this equipment has low voltage output, it is especially susceptible to noise which may result from random electromagnetic fields, or random wave forms which result from normal cycle-to-cycle variations. An illustration of a new system is presented which eliminates these defects. This method utilizes a high voltage output signal and is composed of inexpensive mechanical-electrical stock parts and components.
Technical Paper


A comprehensive cycle analysis has been developed for four-stroke spark-ignited engines from which the indicated performance of a single cylinder engine was computed with a reasonable degree of accuracy. The step-wise cycle calculations were made using a digital computer. This analysis took into account mixture composition, dissociation, combustion chamber shape (including spark plug location), flame propagation, heat transfer, piston motion, engine speed, spark advance, manifold pressure and temperature, and exhaust pressure. A correlation between the calculated and experimental performance is reported for one engine at a particular operating point. The calculated pressure-time diagram was in good agreement with the experimental one in many respects. The calculated peak pressure was 10 per cent lower and the thermal efficiency 0.8 per cent higher than the measured values. Thus this calculational procedure represents a significant improvement over constant volume cycle approximations.
Technical Paper

A Single Cylinder Engine Deposit Test

This paper describes the development of a small and inexpensive single cylinder engine test method for studying the influence of experimental fuels, lubricants, and additives on combustion-chamber deposits. The test operates on a minimum of fuel and lubricant, providing samples of deposits that are chemically similar to those from full-scale engines. These samples are then carefully examined and analyzed to determine the effects of combustion-chamber deposits on engine performance. This test method has proved to be a valuable tool in obtaining a better understanding of the problems associated with combustion-chamber deposits.
Technical Paper

Wear Phenomena of Chromium Plated Rings as Revealed by Radioactive Tracers

Chromium wear phenomena of three types have been investigated using a continuous radio-tracing technique in single cylinder engines. The dependence of wear on load at high wall pressures was studied in a gasoline engine using taper faced rings. It was confirmed in a laboratory diesel engine that ring wear was primarily corrosive. Techniques were developed for the rapid assessment of lubricating oils and additives and some detailed examinations of effects of additives and their concentration have been made. Finally, ring scuffing in the gasoline engine was promoted by thermal distortion.
Technical Paper

Why Multicylinder Motorcycle Engines?

Combustion engines with up to 48 cyl have been built. It is shown that this is neither accident nor fanciness when high specific power output is involved. As is demonstrated on hand of equations, the subdivision of a certain displacement into larger numbers of smaller cylinders brings about a substantial increase in power. At this time, for example, more than twice that of single cylinder engines. Values of highly developed motorcycle competition engines are compared with these theoretical results and an amazingly high degree of agreement exists. These laws are not limited to motorcycle engines, but may be used for other applications also.
Technical Paper

Exhaust Emission Abatement by Fuel Variations to Produce Lean Combustion

Differences in the power producing capacities and exhaust emission characteristics of various spark-ignition-engine fuels are frequently obscured by interactions involving the particular engine system used in the comparison. In an attempt to minimize this problem, gasoline, propane, methane, and a hydrogen-methane fuel gas were compared in a single cylinder engine under conditions that were optimum for each fuel. The resulting data, coupled with an estimated duty cycle representative of traffic service, permitted the development of internally comparable data on fuel consumption and exhaust emissions. Smog-inducing hydrocarbon emissions from the exhaust of a propane-fueled engine can be less than 13% of the minimum value obtainable with a gasoline fueled engine. Such emissions would be substantially eliminated with a well designed methane engine.
Technical Paper

The Ignition of a Premixed Fuel and Air Charge by Pilot Fuel Spray Injection with Reference to Dual-Fuel Combustion

Dual fuel engines compress the air/gas fuel mixture to just below autoignition conditions and then ignite it by the injection of a small amount of liquid fuel. The use and performance of these engines, however, have been limited by knock. Single cylinder engine experiments show that this limitation is a readily defined autoignition phenomenon, and can be analyzed by a mathematical model that indicates the effects on performance imposed by fuel changes and operating conditions. Experimental findings confirm that these performance data correlate broadly with those obtained conventionally in standard spark ignited or motored engines.
Technical Paper

Canister Purge Flow Control Study on EFI Single Cylinder Small Engine

With increasingly stringent emission requirement in China the evaporative emission legislation for motorcycles has been issued since July of 2008. According to the vehicle investigation two type effective solutions for EFI engine can be optional for this requirement: Passive system (not controlled by EMS) and active system (controlled by EMS). For passive system how to ensure enough purge flow but minimize the influence on mixture formation is the key and for active type, the point will focus on how to control and calculate the exact purge flow amount with the fluctuated intake air pressure for single cylinder engine. In this paper the strategy for both purge flow control solutions has been presented especially for single cylinder motorcycle engine.
Journal Article

Spray Formation and Combustion Analysis in an Optical Single Cylinder Engine Operating with Fresh and Aged Biodiesel

The present paper describes the results of a cooperative research project between GM Powertrain Europe and Istituto Motori - CNR aimed at studying the impact of both fresh and highly oxidized RME at two levels of blending on spray formation and combustion in modern automotive diesel engines. The tests were performed on an optical single-cylinder engine sharing combustion system configuration with the 2.0L Euro5 GM diesel engine for passenger car application. Two blends (B50 and B100) blending were tested for both fresh and aged RME and compared with commercial diesel fuel in two different operating points typical of NEDC (1500rpm/2bar BMEP and 2000rpm/5bar BMEP). The experimental activity was devoted to an in-depth investigation of the spray density, breakup and penetration, mixture formation, combustion and soot formation, by means of optical techniques.
Journal Article

A Thermodynamic Model for a Single Cylinder Engine with Its Intake/Exhaust Systems Simulating a Turbo-Charged V8 Diesel Engine

In this paper, a thermodynamic model is discussed for a single cylinder diesel engine with its intake and exhaust systems simulating a turbo-charged V8 diesel engine. Following criteria are used in determination of the gas exchange systems of the single cylinder engine (SCE): 1) the level of pressure fluctuations in the intake and exhaust systems should be within the lower and upper bounds of those simulated by the thermodynamic model for the V8 engine and patterns of the pressure waves should be similar; 2) the intake and exhaust flows should be reasonably close to those of the V8 engine; 3) the cylinder pressures during the combustion and gas exchange should be reasonably close to those of the V8 engine under the same conditions for the valve timing, fuel injection, rate of heat release and in-cylinder heat transfer. The thermodynamic model for the SCE is developed using the 1D engine thermodynamic simulation tool AVL BOOST.
Technical Paper

Hydrogen Fueled Homogeneous Charge Compression Ignition Engine

Hydrogen was used to operate a single cylinder engine in homogeneous charge compression ignition (HCCI) mode. The engine was a modified 435 cm3 single cylinder air cooled Yanmar L100V direct injection (DI) compression ignition (CI) engine. The original diesel fuel injection system was removed and a hydrogen port fuel injection (PFI) system was added, along with a 1 kW intake air heater. The piston was modified from the original re-entrant bowl piston to a dish shaped piston, while maintaining the original 21.2:1 compression ratio. The engine speed was maintained at a constant 1800 RPM. Three hydrogen fueling conditions of 25, 30, and 35 slpm were investigated, which corresponded to an excess air ratio (λ) of roughly 4.38, 3.64, and 3.16, respectively The fuel conversion efficiency for the conditions tested ranged from 23% - 27%.
Technical Paper

Shape Optimization of a Single Cylinder Engine Crankshaft

Due to increasing demand for environment friendly vehicles with better fuel economy and strict legislations on greenhouse gas emissions, lightweight design has become one of the most important issues concerning the automobile industry. Within the scope of this work lightweight design potentials that a conventional single cylinder engine crankshaft offers are researched through utilization of structural optimization techniques. The objective of the study is to reduce mass and moment of inertia of the crankshaft with the least possible effect on the stiffness and strength. For precise definition of boundary conditions and loading scenarios multi body simulations are integrated into the optimization process. The loading conditions are updated at the beginning of each optimization loop, in which a multi body simulation of the output structure from the previous optimization loop is carried out.
Journal Article

Impact of Fuel Properties on Diesel Low Temperature Combustion

Extensive empirical work indicates that exhaust gas recirculation (EGR) is effective to lower the flame temperature and thus the oxides of nitrogen (NOx) production in-cylinder in diesel engines. Soot emissions are reduced in-cylinder by improved fuel/air mixing. As engine load increases, higher levels of intake boost and fuel injection pressure are required to suppress soot production. The high EGR and improved fuel/air mixing is then critical to enable low temperature combustion (LTC) processes. The paper explores the properties of the Fuels for Advanced Combustion Engines (FACE) Diesel, which are statistically designed to examine fuel effects, on a 0.75L single cylinder engine across the full range of load, spanning up to 15 bar IMEP. The lower cetane number (CN) of the diesel fuel improved the mixing process by prolonging the ignition delay and the mixing duration leading to substantial reduction of soot at low to medium loads, improving the trade-off between NOx and soot.
Journal Article

Visualization of Propane and Natural Gas Spark Ignition and Turbulent Jet Ignition Combustion

This study focuses on the combustion visualization of spark ignition combustion in an optical single cylinder engine using natural gas and propane at several air to fuel ratios and speed-load operating points. Propane and natural gas fuels were compared as they are the most promising gaseous alternative fuels for reciprocating powertrains, with both fuels beginning to find wide market penetration on the fleet level across many regions of the world. Additionally, when compared to gasoline, these gaseous fuels are affordable, have high knock resistance and relatively low carbon content and they do not suffer from the complex re-fueling and storage problems associated with hydrogen.