Open Chamber Diesel Engine Research Articles

Experimental investigation and kinetics of tomato peel pyrolysis: Performance, combustion and emission characteristics of bio-oil blends in diesel engine

Pyrolysis of tomato peel waste in an indigenous Auger reactor is reported. Tomato peel was subjected to elemental analysis and physicochemical characterisation. The higher heating value of the tomato peel was estimated to be 22.50 MJ kg−1. Thermogravimetric analysis of tomato peel was performed to estimate the temperature of pyrolysis process. Thermal cracking of tomato peel was carried out at different temperatures ranging from 450 °C to 650 °C. The bio oil yield was found to 14%, 17.5%, 32%, 40% and 36% at 450 °C, 500 °C, 550 °C, 600 °C and 650 °C respectively. Kinetic modelling of the tomato peel pyrolysis was performed with three different model free methods to evaluate the activation energy. The activation energy of tomato peel pyrolysis at different heating rates, 5 °C min−1, 10 °C min−1, 15 °C min−1, 20 °C min−1 and 25 °C min−1 were reported to be 112.7 kJ mol−1, 113.85 kJ mol−1 and 234.47 kJ mol−1 respectively by Kissinger, Kissinger Akahira Sunose and Ozawa Flynn Wall models. Tomato peel oil was subjected to Gas chromatography - Mass spectroscopy and Fourier transform infrared spectroscopy analysis to determine the compounds and functional groups. The kinematic viscosity of the tomato peel oil was found to be 11.82 cSt. The flash point of the tomato peel oil was estimated to be 94 °C. Different blends of tomato peel oil and diesel were subjected to testing in a 4-stroke water cooled open chamber diesel engine to evaluate the performance and emission characteristics analysis. The Brake thermal efficiency of 5% blend of tomato peel oil was estimated to be 31.5% under full load condition. Carbon Monoxide emissions of tomato peel oil blends were found to be lesser in comparison with diesel fuel. Techno-economic analysis of the tomato peel pyrolysis was also reported.

A Contribution to the Analysis of Turbulence Anisotropy and Nonhomogeneity in an Open-Chamber Diesel Engine

Further investigation of the turbulence time-frequency spectral structure and its anisotropy and nonhomogeneity has been carried out in the combustion chamber of an automotive diesel engine with a high-squish reentrant in-piston-bowl and a helical intake port. An advanced HWA technique was applied for turbulence measurements along the injector axis, under motored engine conditions in the speed range of 600–3000 rpm. Autospectral density functions of each fluctuating velocity component, as was determined by a specific sensor-wire orientation, were evaluated in consecutive crank-angle correlation intervals during the induction, compression, and early expansion strokes. In order to study the speed dependence of the turbulence-structure anisotropy and nonhomogeneity in different portions of the engine cycle, time-scales of cycle-resolved and conventional turbulent fluctuations were analyzed as functions of the engine speed for different wire orientations, measurement locations, and correlation intervals. Anisotropy and nonhomogeneity were generally significant at low engine speeds, whereas a tendency towards isotropy and homogeneity was found by increasing the speed. With specific reference to the bowl-generated turbulence, spectral anisotropy was remarkable at all speeds in the reverse-squish flow, close to the cylinder-head wall. However, spectral nonhomogeneity was the main feature of the direct-squish flow at low engine speeds.

Effects of Fuel Overpenetration and Overmixing During Ignition-Delay Period on Hydrocarbon Emissions From a Small Open-Chamber Diesel Engine

A quasi-steady gas-jet model was applied to examine the spray trajectory in swirling flow during the ignition-delay period in an open-chamber diesel engine timed to start combustion at top dead center. Spray penetration, deflection, and the fractions of too-lean-mixed, burnable, and overpenetrated fuel at the start of combustion were calculated by employing the measured ignition delay and mean fuel-injection velocity. The calculated parameters were applied to correlate the measured exhaust hydrocarbon (HC) emissions. The engine parameters examined were bowl geometry, compression ratio, overall air-fuel ratio, and speed. Both the ignition delay and the relative spray-penetration parameter, defined as the ratio of the spray-penetration distances at the moments of start of combustion and wall impingement, gave good correlations for some of the engine parameters examined but could not explain all the measured trends. However, good correlation of the measured exhaust HC emissions was obtained by using the calculated too-lean-mixed and overpenetrated fuel fractions at the start of combustion. Correlation of the overpenetrated fuel with the measured HC indicated that approximately 2 percent of the fuel mass that overpenetrated before start of combustion emitted from the engine as unburned HC. This could account for 0 to 65 percent of the total HC emission from this engine. Additionally, it was found that the too-lean-mixed fuel could contribute 10 to 30 percent of the total HC emission, as found in a previous study on a somewhat similar engine. The remaining HC emission is caused by other sources such as bulk quenching.

The Application of Availability and Energy Balances to a Diesel Engine

The maximum power that can be extracted from an engine operating at a given condition was determined by means of analyses based on the first and second laws of thermodynamics. These analyses were applied to a heavy-duty single-cylinder open-chamber diesel engine operated at constant speed. Over the range of operating conditions investigated, the second-law efficiency (ratio of brake power to maximum extractable power) of the engine, which increased with engine load, was found to vary from 22 to 50 percent. It was concluded that besides heat transfer, the combustion process was the most important source of irreversibility and accounted for 25 to 43 percent of the lost power.

Combustion Characteristics of a Single-Cylinder Open-Chamber Diesel Engine

The combustion characteristics of an open-chamber diesel engine were examined by means of heat-release analysis and flame luminosity measurements. Increasing the load was found to decrease premixed burning and correspondingly to increase diffusion burning. During most of the diffusion combustion the burning rate of the fuel appeared to be directly proportional to the amount of unburned fuel present in the cylinder. The duration of heat release in crank-angle degrees increased linearly with load and, in general, increased with decreasing engine speed and retarded injection timing. The measured duration of flame luminosity was significantly longer than the calculated duration of heat release, which suggested that emission of radiation continued long after the heat-release reactions ceased.

An Experimental and Analytical Study of Thermal Loading in an Uncooled Open-Chamber Diesel Engine

Temperatures were measured at several points on the liner and firedeck of an insulated 2-L single-cylinder, open-chamber, diesel engine. These temperatures were found to vary significantly with location. The results of these measurements were compared with the predictions of a three-dimensional time-varying thermostructural model incorporating a single-zone thermodynamic simulation of the gas cycle. On the basis of this comparison, values for several thermal boundary conditions required for engine design were deduced. Using these values, relatively good agreement was found between the experiment and model across the range of experimental conditions.

直噴式ディーゼル機関における燃焼改善に関する一考察

Recently, the improvement of fuel economy and the reduction of exhaust smoke and NO have been successfully achieved by supplying diesel engines with emulsified diesel oil with water particles.In the present paper, the difference between the combustion of injected emulsion and that of diesel oil spray is clarified by means of taking high-speed and color photographs of the flames in engine cylinder and in hot air stream. As the results, the two kinds of fuels show different combustion behaviour each other in the growth of initial flame and in the termination of overall combustion in the cylinder. Then, suitable combustion chamber design for the use of emulsified fuel is discussed on the basis of experimental data for various distributions of spray in various kinds of piston cavities. Some methods of clearing troubles caused by emulsified fuel are also discussed on the basis of performance data on a practical high-speed open-chamber diesel engine.

The Simulation of Air Fuel Mixing in High Swirl Open Chamber Diesel Engines

SYNOPSIS The air fuel mixing process in the high swirl open chamber diesel engine is simulated by a steady state gas jet injected into a steady air swirl flow. The results from the simulation show good agreement with engine studies using high speed photography. An attempt to quantify fuel dispersion has been made through the introduction of a mixing parameter, which allows for combustion system geometry in addition to fuel jet and air swirl momenta.

Effect of Lean Pre-Mixture in the Combustion in Diesel Engine : 3rd Report, Effective Utilization of lean Pre-Mixture

In the present paper, the most effective utilization of lean premixture has been discussed on the basis of the combustion photographsunder different distributions or states of auxiliary fuel. The following points have been confirmed : The intermediates of auxiliary fuel have especially marvelous effect on the mist zone of main fuel spray. Thus, the distribution or the state of pre-mixture in an open chamber diesel engine has often diverse influences on the combustion process. For example, if main fuel is injected in completely gaseous and reactive pre-mixture, the spray wipes the mixture away, and branching reaction takes place in the mixture concentrated. Therefore, the injection in such a mixture has possibly unfavourable effect on the improvement of the combustion of main fuel. From the above facts, it will perhaps be a highly beneficial utilization of lean pre-mixture to push out the auxiliary fuel, which is partially vapourized, by main fuel spray. This is because a contact area is larger and its duration is also longer.