Search Results

The object of this paper is to present the operability of a variable compression ratio engine developed to study the combustion characteristics of alternative fuels under different speed and load regimes when exploitation parameters are changed. The variable compression ratio engine is a modification of a commercial single-cylinder diesel engine with adjustable combustion chamber volume, fuel, and ignition systems, envisioned to operate in spark ignition or compression ignition mode. After explaining the experimental plan, designed to evaluate the engine performance comprehensively, a sample of the engine performance and thermodynamic results under spark ignition mode for a chosen condition of speed and load operation with three compression ratio values (9, 12, 14) and three gasoline-ethanol blends is detailed. Torque, power, fuel consumption, and in-cylinder-pressure-related indicated parameters for the experimental cases carried out, are compared.

In this work, the progressive disassembly method is used to determine the mechanical losses contributed by the different components of a single-cylinder spark ignition engine tested at crankshaft angular speeds of 300−1900 min-1, and lubricant temperatures between 30−35 °C. From the experimental measurements, the losses due to the intake and exhaust manifolds, cylinder head, valve train, camshaft bearings, connecting rod-piston assembly, flywheel, and crankshaft bearings are determined. It is obtained that the elements with the highest contribution are the piston-connecting rod assembly and the cylinder head with contributions of 19.2−36.9% and 27−33.3%, respectively. Additionally, the indicated diagram method is applied to assess the pumping, heat, and blow-by losses of the complete motored engine during the intake and exhaust processes.

The development of energy storage systems has gained increasing interest in recent years, as global energy policies and protocols demand to regulate and use available energy efficiently. Inertia flywheels constitute a simple means of energy storage, which has been integrated into different mechanical systems such as die-cutting machines, internal combustion engines, modern systems such as regenerative braking in automobiles, uninterruptible power systems, etc. In this research work, the design process of a flywheel-based experimental test bench to be used as an up-to 130 kilojouls energy storage capacity, and also to test small capacity internal combustion engines, and to diagnose the performance of engine starters. Setting the requirements and main specifications, the paper presents the followed design process, including the solid modeling, the calculations for the dimensioning of the final concept and prototype.

The subject of control of compression and stroke in engines is still a very contemporary research topic, and there is room for research in this matter, as can be asserted from the literature reviewed. In this paper, we report on the systematic methodology followed to perform the synthesis of a variable displacement slider-crank mechanism, needed to convert a non-road small commercial reciprocating single cylinder diesel engine to a variable compression ratio (VCR) engine for academic research purposes. Preliminary dimensions and space trajectories of the projected variable stroke multilink mechanism, constrained by the design of the base engine, were obtained using the coupler curves of Hrones and Nelson’s atlas. A genetic algorithm methodology was implemented to optimize the mechanism performance, as well as to give advantageous compression ratio and displacement behavior, according to both dimensional and kinematic fitness-criteria.

The purpose of this paper is to summarize the progress achieved by the Combustion Engine Laboratory at Technological University of Pereira in the practical implementation of variable compression methods adaptable to small single cylinder industrial engines. Three alternatives to vary the compression ratio have been studied and realized: the first one consists on the modification of the combustion chamber of a commercial diesel engine and its conversion to a dual ignition engine (spark and compression ignition); the second alternative involves the change of the base slider-crank mechanism of a Petter PJ1 engine by a multi-link mechanism controlled to change the piston stroke as well as the compression ratio; and the third alternative consists on the complete design and construction of a novel eccentric cam-based mechanism, developed to vary the TDC piston position, by modifying the distance between the crankshaft and the cylinder head in a custom-built developed engine.

A Design of experiments methodology was carried out to investigate the effects of compression ratio, cylinder head material, and fuel composition on the engine speed, fuel consumption, warm-up time, and emissions of a carbureted single cylinder air-cooled spark ignited engine. The work presented here is aimed at finding out the sensitivity of engine responses, as well as the optimal combination among the aforementioned parameters. To accomplish this task two cylinder heads, one made of aluminum and the second one of cast iron, were manufactured; an antechamber-type adapter for the spark plug to modify the combustion chamber volume was used. Ethanol/gasoline blends containing 10 and 20 volume percent ethanol were prepared. Engine performance was evaluated based on the changes in engine speed at idle conditions. The concentrations of CO2, CO, and HC in the exhaust were recorded.

It is the aim of the present paper to communicate some preliminary results of the research in progress related to the introduction of LPG as a supplementing fuel for the Colombian power grid supply. Most of the power units operating in Colombian oil wells are running on Diesel fuel and natural gas. Other fuels like LPG, heavy and dual fuel have received attention in recent years, due partially to the necessity to relieve the national overall petroleum dependency problem, and also because of the availability of a sizable amount of LPG derived from natural gas purification. In an effort to assess the use of LPG as a fuel alternative to Diesel and natural gas in oil wells, a field study has been carried out.