Showing papers on "Four-stroke engine published in 2012"

Thermal Analysis And Optimization Of I.C. Engine Piston Using finite Element Method

Abstract: Absract: This paper describes the stress distribution of the seizure on piston four stroke engine by using FEA. The finite element analysis is performed by using computer aided design (CAD) software. The main objectives is to investigate and analyze the thermal stress distribution of piston at the real engine condition during combustion process. The paper describes the mesh optimization with using finite element analysis technique to predict the higher stress and critical region on the component. The optimization is carried out to reduce the stress concentration on the upper end of the piston i.e (piston head/crown and piston skirt and sleeve). With using computer aided design(CAD), Pro/ENGINEER software the structural model of a piston will be developed. Furthermore, the finite element analysis performed with using software ANSYS.

Performance investigations of a diesel engine using ethyl levulinate-diesel blends

Abstract: Ethyl levulinate (EL) can be produced from bio-based levulinic acid (LA) and ethanol. Experimental investigations were conducted to evaluate and compare the performances and exhaust emission levels of ethyl levulinate as an additive to conventional diesel fuel, with EL percentages of 5%, 10%, 15% (with 2% n-butanol), and 20% (with 5% n-butanol), in a horizontal single-cylinder four stroke diesel engine. Brake-specific fuel consumptions of the EL-diesel blends were about 10% higher than for pure diesel because of the lower heating value of EL. NOx and CO2 emissions increased with engine power with greater fuel injections, but varied with changing EL content of the blends. CO emissions were similar for all of the fuel formulations. Smoke emissions decreased with increasing EL content.

Comparative study of the combustion, performance, and emission characteristics of a variable compression ratio engine fuelled with diesel, corn oil methyl ester, and palm oil methyl ester

Abstract: The effect of compression ratio on combustion, performance, and emission characteristics of a direct injection single cylinder four stroke variable compression ratio multi fuel engine when fueled with corn oil methyl ester (COME) and palm oil methyl ester (POME) is investigated and compared with petroleum based diesel fuel (PBDF). The suitability of COME and POME as biofuels has been studied in this research. Biodiesels produced from corn oil and palm oil by transesterification process has been used in this study. Experiments were conducted at constant speed of 1500 rpm, full load, and at compression ratio of 17:1, 18:1, and 19:1. The effect of compression ratio on heat release rate, specific fuel consumption, and exhaust gas emissions has been investigated and presented. The fuels which gave best performance when used in engine have been identified by optimum compression ratio. The results indicate that shorter ignition delay, maximum rate of combustion pressure, and lower heat release rate at higher compression ratio were observed for POME when compared to PBDF. The brake thermal efficiency of POME was found to be maximum than PBDF at full load for all compression ratio. Exhaust gas temperature is low for biodiesels when compared to PBDF from compression ratio 17:1 to 19:1. The emission of CO, CO2, and HC dropped with compression ratio 17:1 and it slightly increased when compression ratio is increased. The engine performance was found to be optimum when using POME as fuel, at compression ratio 19:1 during full load condition.

Dynamic model of a two-cylinder four-stroke internal combustion engine and vibration treatment

Abstract: Engine vibrations of large amplitude are caused by inertial effects of the piston–crankshaft mechanism and gas forces, and are transmitted to the chassis of a vehicle in the form of periodically va...

System and method for controlling fuel injection in an engine based on piston temperature

Abstract: A system according to the principles of the present disclosure includes a temperature estimation module and a fuel control module. The temperature estimation module estimates a piston temperature associated with a cylinder based on engine operating conditions. The fuel control module controls at least one of injection timing associated with the cylinder, injection pressure associated with a cylinder, injection location associated with a cylinder, and a number of injections per engine cycle associated with the cylinder based on the piston temperature.

Performance evaluation of a diesel engine by using producer gas from some under-utilized biomass on dual-fuel mode of diesel cum producer gas

Abstract: Producer gas through gasification of biomass can be used as an alternate fuel in rural areas due to high potential of biomass resources in India. Experiments were conducted to study the performance of a diesel engine (four stroke, single cylinder, 5.25 kW) with respect to its thermal efficiency, specific fuel consumption and diesel substitution by use of diesel alone and producer gas-cum-diesel (dual fuel mode). Three types of biomass, i.e. wood chips, pigeon pea stalks and corn cobs were used for generation of producer gas. A producer gas system consisting of a downdraft gasifier, a cooling cum cleaning unit, a filtering unit and a gas air mixing device was designed, fabricated and used to power a 5.25 kW diesel engine on dual fuel mode. Performance of the engine was reported by keeping biomass moisture contents as 8%, 12%, 16%, and 21%, engine speed as 1 600 r/min and with variable engine loads. The average value of thermal efficiency on dual fuel mode was found slightly lower than that of diesel mode. The specific diesel consumption was found to be 60%-64% less in dual fuel mode than that in diesel mode for the same amount of energy output. The average diesel substitution of 74% was observed with wood chips followed by corn cobs (78%) and pigeon pea stalks (82%). Based on the performance studied, the producer gas may be used as a substitute or as supplementary fuel for diesel conservation, particularly for stationary engines in agricultural operations in the farm.

Numerical model to study the valve overlap period in the Wärtsilä 6L 46 four-stroke marine engine

Abstract: In this paper, a CFD (Computational Fluid Dynamics) analysis was carried out to study the Wartsila 6L 46 medium-speed, four-stroke marine engine For the purpose, the commercial software ANSYS Fluent 63 was employed The aim is to analyze the scavenging of gases, especially during the valve overlap period Particularly, the pressure, velocity and mass fraction fields were numerically obtained In order to validate the CFD results, the in-cylinder pressure was successfully compared to experimental measurements for the exhaust, intake and compression strokes of the cylinder operation This model can be used in future works to improve the performance of these engines because the information provided is very useful to identify regions in which the pressure, velocity or distribution of gases are inadequate Besides, to compute the quantity of burnt gases which remain inside the cylinder, fresh charge which is expelled through the exhaust valves and study the influence of parameters such as the exhaust and intake pressures, engine speed, cam profile design, etc

Method and system for engine cylinder decompression

Abstract: A system for actuating an engine valve to decompress an engine cylinder for engine start up and/or engine braking is disclosed. The system may include a first member, such as an outer piston, disposed above an engine valve, which receives an inner piston extending into a bore provided in the first member. One or more springs may bias the inner piston into a predefined position in the first member. The inner piston may include a lower surface that directly, or through an intervening sliding pin, actuates an engine valve in response to the application of fluid pressure on the inner piston. The inner piston may be used to decompress an engine cylinder for engine start up and/or to provide engine braking.

High-Squish Combustion Chamber With Side Injection

Abstract: A combustion chamber for an internal combustion engine is disclosed in which the piston has a large squish region at a peripheral location on the piston top and a depression in the center of the piston top. A side injector sprays fuel into the depression in the piston top through a channel defined in the squish region. In some embodiments, two injectors are provided that are diametrically opposed to each other. In some embodiments, the engine is an opposed-piston engine in which each piston has the squish regions and depressions in the piston top.

Finite Element Analysis and Optimization of Crankshaft Design

Abstract: In this study a static analysis was conducted on a cast iron crankshaft from a single cylinder four stroke engine. Finite element analysis was performed to obtain the variation of the stress magnitude at critical locations. Three dimensional model of the crankshaft was created in ProE software. The load was then applied to the FE model and boundary conditions were applied as per the mounting conditions of the engine in the ANSYS. Results obtained from the analysis were then used in optimization of the cast iron crankshaft. This requires the stress range not to exceed the magnitude of the stress range in the original crankshaft. The optimization process included geometry changes without changing connecting rod and engine block.

An Experimental Investigation on the Potential of Hydrogen in the Reduction of the Emission Characteristics of an Existing Four-Stroke Single-Cylinder Diesel Engine Operating Under EGR

Abstract: The present work attempts to explore the emission characteristics of an existing single-cylinder four-stroke compression-ignition engine operated in dual-fuel mode with hydrogen as an alternative fuel. Experimental investigation was carried out with the engine being subjected to different loads at a predefined flow rate of hydrogen induction. The emission characteristics revealed a 71% and a 40.5% reduction of CO2 emissions at 20% and 80% load, respectively, for non-EGR (exhaust gas recirculation) hydrogen enrichment. In CO emissions, non-EGR hydrogen enrichment registered a 69.5% and a 64.3% reduction at 20% and 40% load, respectively. Smoke emissions saw a 61.5% and a 64.3% reduction during non-EGR hydrogen enrichment at 20% and 40% load, respectively. Hydrocarbon (HC) emissions were reduced by 80% and 60.9% as compared with diesel operation at 20% and 60% loads, respectively. Hydrogen enrichment operations without EGR were penalized, however, with an increase of 79.3% and 81.3% in NOx at 40% and 60% lo...

Vibration measuring method of engine speed by applying four-point energy centrobaric correction method

Abstract: The invention discloses a vibration measuring method of engine speed by applying a four-point energy centrobaric correction method, which comprises the steps of: discrete-sampling a vibration acceleration signal on the surface of an engine block to obtain a time series; obtaining a frequency domain signal X1(f) through fast Fourier transformation of Zn(t); correcting the peak frequency fi of X1(f) by adopting a four-point energy centrobaric correction method, and obtaining a corrected frequency; obtaining a time spectrum signal ZZn(t) through carrying out self-related transformation and fast Fourier transformation on the frequency domain signal X1(f); correcting the time ti corresponding to the peak of ZZn(t) by adopting the four-point energy centrobaric correction method again, and obtaining the corrected time; and finding the accurate 1/2 harmonic frequency value of the rotating speed w of the four stroke engine according to the corrected frequency and time, and calculating the rotating speed w of the engine through a relational expression. The vibration measuring method of engine speed can solve the problem that the rotating speed of the engine cannot be detected when the number of engine blocks cannot be determined; and the method has the advantages of better universality, high noise-proof performance and accurate and reliable result.

Four-stroke engine

Abstract: A four-stroke engine is provided to lubricate driving parts including a crankshaft and valve operating members while circulating oil, using pressure fluctuation in a crank chamber, the pressure fluctuation being caused by reciprocating motion of a piston. A cam driving parts move with rotation of the crankshaft; a driving chamber and a rocker chamber are connected to one another; the rocker chamber is connected to the crank chamber and a gas-liquid separator; the oil accumulated in a tank is sucked up into the crank chamber and circulated through each part of the four-stroke engine; the crank chamber and the driving chamber are connected to one another via a communicating passage and a return passage; and the crank chamber and the driving chamber connected to one another via the return passage communicate with one another only when the piston is located in a vicinity of the top dead center.

Split Cycle Phase Variable Reciprocating Piston Spark Ignition Engine

Abstract: A split cycle phase variable reciprocating piston spark ignition engine comprising a compressor unit having a compression chamber adapted to carry out the intake and compression strokes of a four stroke engine cycle, a power unit having an expansion chamber adapted to carry out the expansion and exhaust strokes of a four stroke engine cycle, a crossover gas passage for transferring compressed gas from the compression chamber to the expansion chamber, an expansion chamber volume modifier to provide nearly full load like combustion chamber condition at all the engine load conditions by means of modifying volume and shape of the expansion chamber, a phase altering mechanism for altering phase relation between the compressor unit and the power unit as a function of engine load variation, an electronic control unit for providing control commands for various electrically operated actuators and motors.

Exergy analysis of a compression ignition engine

Abstract: In this study, energy and exergy analysis are applied to the experimental data of a naturally aspirated, direct injection, single cylinder, 4 stroke diesel engine. The data are collected using an engine test unit which enables the measurement of fuel flow rate, air flow rate, engine load, incylinder pressure and volume as a function of crank angle and all relevant temperatures. The development of rate and cumulative in-cylinder exergy rate terms during an engine cycle are shown in a diagram which identifies the processes in which exergy destruction due to irreversibilties are involved. The energy and exergy efficiencies are calculated for different loads and compared. It is found that combustion is the dominant irreversibility term and that it decreases with increase in load.

Experimental Investigation on the Effect of Adding Di Methyl Carbonate to Gasoline in a SI Engine Performance

Abstract: Di methyl carbonate (DMC) has a lot of good properties to be used as a blend with gasoline. In order to improve the efficiency, combustion stability and emission performance of a spark ignition engine, oxygenated fuel (DMC) is added to a gasoline. In this experimental work, the effect of using 100% gasoline and gasoline-DMC blends (D5, D10, D15 and D20) on four cylinder engine performance and exhaust emissions were investigated for different engine speeds. The investigation was conducted on a multi c ylinder, four stroke spark ignition engine. The emissions were measured using exhaust gas analyzer. The experimental results show that the blending of DMC with gasoline increases the thermal efficiency of engine as compared to 100% gasoline as a fuel. The study also found that decrease of CO and HC with the blending of DMC with gasoline.

Experimental investigation of thermoelectric heat recovery from a diesel engine

Abstract: The paper presents several actions in the field of waste heat harvesting from exhaust gas and surfaces of diesel engines by means of thermoelectric modules. It illustrates preliminary research work performed by the authors for the investigation of TEG efficiency when mounted on diesel engine exhaust gas systems, stressing on the validation of the measurement chain. A four stroke, two cylinder, diesel engine, rated at 20 kW @ 1800 rpm was tested in eight operation modes, finding the weights of each term from the engine energy balance. Two Peltier elements - TEC1-12710 - were set on exhaust pipe, being connected to a HYTEK iUSBDAQ - U120816, data acquisition system controlled by National Instruments LabVIEW virtual instrumentation software. The research work had three phases. The first one used a metal plate to support the thermoelectric elements; the temperature sensors were set into three metal blocks acting as coolers for the heat sink. In the second phase, the thermoelectric elements were mounted directly on the exhaust gas pipe, being measured twelve points [ voltage -gas temperature ]. In the third phase, the thermoelectric elements were mounted using an aluminum cooler. The temperature measurement accuracy was validated by means of infrared thermography. The second method proved to be the best; practical results of power generation were compared with literature values showing good correlation and a precise operation of the data acquisition system.

Method for controlling internal combustion engine, internal combustion engine, and vehicle equipped with same

Abstract: A method for controlling an internal combustion engine, an internal combustion engine, and a vehicle equipped with the same which reduce roll vibrations due to a power plant including a multi-cylinder internal combustion engine and a support apparatus during start of the internal combustion engine without impairing its startability. A control apparatus of a multi-cylinder internal combustion engine includes: a device for determining whether or not a rotational speed of the engine is within a resonance-rotational-speed region around a resonance rotational speed at which resonance occurs due to the rotational speed, a power plant including the engine, and rubber mounts of the power plant; and a device for controlling injectors such that fuel injection amounts of respective cylinders become uneven when the rotational speed is within the resonance-rotational-speed region.

Four-stroke internal combustion engine with engine brake

Abstract: The invention relates to a four-stroke internal combustion engine with an engine brake (2), with at least one exhaust valve (4a, 4b) per cylinder, said valve being actuated by means of a camshaft (6) and at least one valve lever arrangement (5), and with an arrangement for advancing the exhaust control system, the valve lever arrangement (5) having an exhaust lever (5b), which is actuated by an exhaust cam (12), and a brake lever (5a), which can be actuated by a brake cam (10). According to the invention, in order to produce an engine brake having dual braking phases as simply as possible and with minimal space requirements, the brake lever (5a) can be actuated by means of a switchable first transmission member (9) which is disposed between the brake lever (5a) and brake cam (10), the brake lever (5a) being activated in a first position of the first transmission member (9) and deactivated in a second position of the first transmission member (9).