Showing papers on "Four-stroke engine published in 2009"

Effects of cerium oxide nanoparticle addition in diesel and diesel-biodiesel-ethanol blends on the performance and emission characteristics of a ci engine

Abstract: An experimental investigation is carried out to establish the performance and emission characteristics of a compression ignition engine while using cerium oxide nanoparticles as additive in neat diesel and diesel-biodiesel-ethanol blends. In the first phase of the experiments, stability of neat diesel and diesel-biodiesel-ethanol fuel blends with the addition of cerium oxide nanoparticles are analyzed. After series of experiments, it is found that the blends subjected to high speed blending followed by ultrasonic bath stabilization improves the stability. The phase separation between diesel and ethanol is prevented using vegetable methyl ester (Biodiesel) prepared from the castor oil through transesterification process. In the second phase, performance characteristics are studied using the stable fuel blends in a single cylinder four stroke computerised variable compression ratio engine coupled with an eddy current dynamometer and a data acquisition system. The cerium oxide acts as an oxygen donating catalyst and provides oxygen for the oxidation of CO or absorbs oxygen for the reduction of NOx. The activation energy of cerium oxide acts to burn off carbon deposits within the engine cylinder at the wall temperature and prevents the deposition of non-polar compounds on the cylinder wall results reduction in HC emissions. The tests revealed that cerium oxide nanoparticles can be used as additive in diesel and diesel-biodieselethanol blend to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

Combustion Characteristics of Diesohol Using Biodiesel as an Additive in a Direct Injection Compression Ignition Engine under Various Compression Ratios

Abstract: An experimental investigation is carried out to study the combustion characteristics of diesel−biodiesel−ethanol blends in a single-cylinder four stroke direct injection variable compression ratio engine under the compression ratios 15:1, 17:1, and 19:1. As the ethanol is immiscible with diesel, biodiesel (jatropha methyl ester) is used as an additive to prevent the phase separation of the diesel−ethanol blends. The addition of ethanol decreases the cetane number of the blend, whereas the biodiesel addition improves the cetane number of the resultant mixture. The combustion characteristics of the stable fuel blends (D85B10E5, D80B10E10, D75B10E15, D70B10E20, and D65B10E25) are studied and compared with neat diesel by conducting experiments on the computerized variable compression ratio engine test rig. A piezoelectric pressure sensor and a crank angle encoder are used to record the cylinder gas pressure and a crank angle, respectively, to determine the combustion parameters. It is observed that the cylind...

Modelling and optimizing two- and four-stroke hybrid pneumatic engines

Abstract: Hybrid pneumatic engines, which are designed to follow the downsizing and supercharging paradigm, offer a fuel-saving potential that is almost equal to that of hybrid electric powertrains while inducing much lower additional mass and cost penalties. This paper presents a systematic optimization of the operation of such an engine system. Both two-stroke and four-stroke modes are analysed. The optimized valve and throttle actuation laws for all modes and operating areas lead to generic maps that are independent of the engine size. So far, the pneumatic hybridization of internal combustion engines was thought to require two-stroke operation. This paper presents a novel hybrid pneumatic engine configuration that entails fixed camshafts for both intake and exhaust valves while utilizing variable valve actuation for one charge valve per cylinder only. This configuration is operated entirely in four-stroke modes. Such a configuration requires a careful optimization of its operating strategy to achieve its fuel economy potential. Compared with a full two-stroke operation, only small efficiency losses result from using four-stroke modes with these new operating strategies. Initial measurement results with such an engine system are presented in this paper to confirm the validity of the principles of operation.

Performance and emission characteristics of a diesel engine with castor oil

Abstract: Bio-diesel is one of the most promising alternatives for diesel needs. Use of edible oil may create shortage of oil seeds for daily food, which necessitates identification of new kinds of non-edible vegetable oil. With this objective, the present work has focused on the performance of castor non-edible vegetable oil and its blend with diesel on a single cylinder, 4 stroke, naturally aspirated, direct injection, water cooled, eddy current dynamometer Kirloskar Diesel Engine at 1500 rpm for variable loads. Initially, castor neat oil and their blends were chosen. The physical and chemical properties of Castor oil were determined. In general, viscosity of neat vegetable oil is high, which can be reduced through blending with diesel and heating them. The heating temperature of the blends increases with the increase in the percentage of neat oils with diesel ranging from 70°C to 120°C before entering into the combustion chamber. The suitability of neat Castor oil and their blends are evaluated through experimentation. The performance and emission characteristics of engine are determined using Castor neat oil and their blends with diesel. These results are compared to those of pure diesel. These results are again compared to the other results of neat oils and their blends available in the literature for validation. By analyzing the graphs, it was observed that the performance characteristics are reduced and emission characteristics are increased at the rated load compared to those of diesel. This is mainly due to lower calorific value, high viscosity and delayed combustion process. From the critical analysis of graphs, it can be observed that 25% of neat Castor oil mixed with 75% of diesel is the best suited blend for Diesel engine without heating and without any engine modifications. It is concluded that castor non-edible oil can be used as an alternate to diesel, which is of low cost. This usage of neat bio-diesel has a great impact in reducing the dependency of India on oil imports.

Emission Characteristics of Sunflower Oil Methyl Ester

Abstract: In this study, use of sunflower oil methyl ester as an alternative fuel in a 4 stroke turbo diesel engine with 4 cylinders, direct injection, and 55 kW power was analyzed The engine has been fueled by diesel fuel and biodiesel (B100) obtained from methyl ester of sunflower oil and by running the test engine with 14 different speeds and full load, the results have been analyzed Smoke emissions obtained in biodiesel use were slightly less, which could be attributed to better combustion efficiency Also, HC and CO emissions of biodiesel were found to be lower Results of this study show that performance values of sunflower oil methyl ester are similar to those of diesel fuel It can be concluded that biodiesel's exhaust emissions are lower than diesel fuels, which indicates that biodiesel has more favorable effects on air quality

An experimental investigation on manifold-injected hydrogen as a dual fuel for diesel engine system with different injection duration

Abstract: Stringent emission norms and rapid depletion of petroleum resources have resulted in a continuous effort to search for alternative fuels. Hydrogen is one of the best alternatives for conventional fuels. Hydrogen has both the benefits and limitation to be used as a fuel in an automotive engine system. In the present investigation, hydrogen was injected into the intake manifold by using a hydrogen gas injector and diesel was introduced in the conventional, mode which also acts as an ignition source for hydrogen combustion. The flow rate of hydrogen was set at 5.5 l min−1 at all the load conditions. The injection timing was kept constant at top dead center (TDC) and injection duration was adjusted to find the optimized injection condition. Experiments were conducted on a single cylinder, four stroke, water-cooled, direct injection diesel engine coupled to an electrical generator. At 75% load the maximum brake thermal efficiency for hydrogen operation at injection timing of TDC and with injection duration of 30°CA is 25.66% compared with 21.59% for diesel. The oxides of nitrogen (NOX) emission are 21.7 g kWh−1 for hydrogen compared with diesel of 17.9 g k Wh−1. Smoke emissions reduced to 1 Bosch smoke number (BSN) in hydrogen compared with diesel of 2.2 BSN. Hydrogen operation in the dual fuel mode with diesel exhibits a better performance and reduction in emissions compared with diesel in the entire load spectra. Copyright © 2009 John Wiley & Sons, Ltd.

Performance and emission characteristics of CI engine fuelled with non edible vegetable oil and diesel blends.

Abstract: The objective of this study is to compare the engine performance and emission results of biodiesel derived from Jatropha oil when applied in different proportions in a stationary diesel engine without any engine modifications. A single cylinder four stroke diesel engine was tested at various loads with the blended fuel at the rated speed of 1500 rpm. Esterified Jatropha oil and diesel blends having 10%, 20%, 30%, 40% and 50% Jatropha oil on volume basis and pure diesel were used as fuel. Engine performance with pure diesel was also evaluated for comparison. An AVL 5 gas analyzer and a smoke meter were used for the measurements of exhaust gas emissions. Engine performance (specific fuel consumption, brake thermal efficiency, and exhaust gas temperature) and emissions (HC, CO, CO2, NOX and Smoke Opacity) were measured to evaluate and compute the behaviour of the diesel engine running on biodiesel. The results show that the brake thermal efficiency of diesel is higher at all loads followed by blends of Jatropha oil and diesel. Experimentally the maximum brake thermal efficiency and minimum specific fuel consumption were found for blends upto 20% Jatropha oil at all loads among the blends. The specific fuel consumption was found to be even lower than the conventional diesel for blends up to B20. The brake thermal efficiency for B10 and B20 were also closer to diesel and the CO2 emissions were found to be lesser than diesel while there was a marginal increase in the smoke opacity and NOX. The increase in opacity can be effectively managed by engine optimization. The reductions in brake specific fuel consumption and CO2 emissions made the blend of biodiesel B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution.

Investigation of SI-HCCI Hybrid Combustion and Control Strategies for Combustion Mode Switching in a Four-Stroke Gasoline Engine

Abstract: Homogeneous charge compression ignition (HCCI) combustion, also known as controlled autoignition (CAI) combustion, has been realized over a range of engine speed and load conditions in a single cylinder four-stroke gasoline engine equipped with a 4VVAS mechanical variable intake and exhaust valve lift and timing devices system. The engine has the capability to operate either in the spark ignition (SI) or HCCI combustion in order to cover the complete engine operational range. Therefore, smooth switching between SI and HCCI modes is required. In this work, a systematic investigation has been carried out to study the transition between the conventional spark ignition combustion and HCCI combustion and develop the control strategies for optimized mode switch. Results show that dynamic transitions between HCCI and SI can be stably achieved around the boundaries of HCCI operation region through the rapid and effective control of the in-cylinder residual gas concentration by a Four Variable Valve Actuation Syst...

Combustion Temperature Effect of Diesel Engine Convert to Compressed Natural Gas Engine

Abstract: Effect of combustion temperature in the engine cylinder of diesel engine convert to Compressed Natural Gas (CNG) engine was presents in this study. The objective of this study was to investigate the engine cylinder combustion temperature effect of diesel engine convert to CNG engine on variation engine speed. Problem statement: The hypothesis was that the lower performance of CNG engine was caused by the effect of lower in engine cylinder temperature. Are the CNG engine is lower cylinder temperature than diesel engine? This research was conducted to investigate the cylinder temperature of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: In this study, the combustion temperature was investigated in 7 cases engine speed. The engine speeds variation start from 1000 rpm until 4000 rpm with variation in 500 rpm. The engine conversion development and combustion temperature investigation was conducted at automotive laboratory, faculty of mechanical engineering, University Malaysia Pahang, Malaysia. Results: The results of the combustion temperature in the engine cylinder in variation engine speeds showed that diesel engine convert to CNG engine effect decrease the combustion temperature in the engine cylinder characteristics. Conclusion/Recommendations: In the low speed the conversion can be increase the combustion temperature, but the increasing engine speeds can be decrease the combustion temperature in the engine cylinder.

Control apparatus for a cylinder direct-injection internal combustion engine

Abstract: A control apparatus is provided for a four stroke cylinder direct-injection internal combustion engine having a cylinder and a piston disposed within the cylinder. The control apparatus includes a variable compression ratio mechanism for variably controlling the engine compression ratio by changing the top dead center position of the piston and a fuel injection device for injecting fuel directly into the cylinder. When the actual compression ratio of the engine is higher than a target compression ratio, the variable compression ratio mechanism reduces the compression ratio, and in accordance with the reduction in the compression ratio, the fuel injecting device injects an intake fuel injection amount in the intake stroke and a compression fuel injection amount in the compression stroke, and the timing for starting the fuel injection in the compression stroke is retarded.

Engine Lubrication Method

Abstract: An engine lubrication method is provided. The four-cycle engine has an engine block having a cylindrical bore and an enclosed oil reservoir. A crankshaft is mounted in the engine block. An oil pump driven by the cam gear, brings the oil from the oil reservoir and the valve chamber. The engine is provided with a cylinder head assembly having a pair of overhead intake and exhaust valves. A circular arc wall surrounds the web of the crankshaft at a slight distance from the web. The crankshaft web causes the oil to fly to lubricate engine parts and the oil, returns into the oil reservoir by a check valve. Flowing of oil in to the combustion chamber when the engine is oriented to incline is prevented by oil recesses and long pipes. Another lubrication and breathing system without pump is presented, wherein construction except pump is basically followed.

Effect of Diesel Engine Converted to Sequential Port Injection Compressed Natural Gas Engine on the Cylinder Pressure vs Crank Angle in Variation Engine Speeds

Abstract: The diesel engine converted to compressed natural gas (CNG) engine effect is lower in performance. Problem statement: The hypothesis is that the lower performance of CNG engine is caused by the effect of lower in engine cylinder pressure. Are the CNG engine is lower cylinder pressure than diesel engine? This research is conducted to investigate the cylinder pressure of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: The research approach in this study is by convert the diesel engine to multi point injection dedicated CNG engine. The engine conversion is by changed the diesel fuel to CNG fuel, changed the injection fuel system, changed the ignition system, modified piston to reduce the compression ratio and added throttle to in intake port. If the development is completed, the engine cylinder pressure is investigated. In this study, the cylinder pressure is investigated in 7 cases engine speed from 1000 to 4000 rpm with range in 500. Results: The research results are cylinder pressure and maximum pressure of CNG engine compared to diesel engine in 1000 to 4000 rpm engine speed. Conclusion/Recommendations: Effect of diesel engine converted to CNG engine is decrease the cylinder pressure. The further research is needed to find the higher performance of CNG engine.

The performance characteristics of a hydrogen-fuelled free piston internal combustion engine and linear generator system

Abstract: A power generation system that utilizes a hydrogen-fuelled free piston engine (FPICE) and a linear generator are under development. A FPICE gives power output more efficiently compared with conventional reciprocating piston engines, because it utilizes many benefits such as low friction loss and inherently variable compression ratio apart from the low emission of hazardous exhaust gases. In addition, if hydrogen fuel is used in an FPICE, it would be possible to make the exhaust emission level almost zero without sacrificing the efficiency. In this study, a prototype FPICE, two-stroke twin-cylinder engine, was developed and a linear generation system was incorporated in between the cylinders to get the electricity and the start of the engine, as well. It was possible to operate the engine at a velocity of 17 Hz. The FPICE was found to give different piston positions at top dead centre, and this irregular piston movement affected significantly both the compression process and the subsequent combustion of the other cylinder of the engine at the same time. Both compressed natural gas and hydrogen were used to the test engine, and the results showed different combustion characteristics with the fuels used. Since the scavenging efficiency easily gets worse in such a low-speed operation of the two-stroke engines, hydrogen fuel has been found to give higher burn rate and resultantly to show improvements in power output and the emissions.

Method and device of a control for a start- stop control operation of an internal combustion engine

Abstract: In a method of control for a start-stop operation of an internal combustion engine in a motor vehicle for briefly stopping and starting the internal combustion engine, which is started by an electric machine as starter, a detection device detects the position and the rotational speed of a crankshaft following the switch-off of the internal combustion engine. The curve of the rotational speed of the crankshaft following the switch-off of the internal combustion engine is actively and instantaneously calculated in advance.

Quasi Free Piston Engine

Abstract: A quasi free piston engine uses, a small, lightweight crankshaft to connect the piston assemblies of the free piston engine with a flywheel. While most of the power output from the combustion pistons is extracted by pumping pistons as hydraulic power, the small crankshaft and flywheel ensure exact TDC position of the combustion pistons in operation, and provide a rotating means to drive combustion cylinder intake and exhaust valves. Flywheel speed may be monitored to provide feedback on power extraction for further control of the system. In addition, a hydraulic push-rod system for efficient valve actuation is provided.

Portable gas powered internal combustion engine arrangement

Abstract: A gas powered internal combustion engine in which the gas is provided from pressurized liquid gas in an LPG container and in which the LPG container is rigidly mounted adjacent to the internal combustion engine at a preselected angle to be in conductive heat transfer relationship to the internal combustion engine and in vibration receiving relationship to the internal combustion engine whereby the liquified gas in the LPG container is heated and the effective surface area thereof is increased.

Waste heat engine

Abstract: An engine includes a radial arrangement of cylinders each having a reciprocating piston with a piston head and a connecting rod pivotally linked to the piston head at an upper end. A lower end of each connecting rod is pivotally linked to a crank disk that is rotatably mounted on a crank arm of a crankshaft. Steam intake valves at each cylinder are momentarily opened by a bearing cam roller that is moved in a circular path by rotation of the crank disk to sequentially engage spring urged cam followers on inboard ends of radially extending valve stems. Low pressure steam or gas is injected into the top of each cylinder, as the intake valves of the cylinders are opened in sequence, thereby forcing the piston in each cylinder through a power stroke to move the crank disk and turn the crankshaft. Angular displacement of each connecting rod through the return stroke of the piston urges an exhaust reed valve on the piston head to an open position, thereby releasing exhaust steam to a condenser chamber. The engine is self- starting and operates in a low pressure, low temperature range, using waste heat from an external source, such as exhaust from an internal combustion engine, burning of refuse (e.g. garbage or other solid waste material) or solar heat.

An analytical and experimental study of performance on jatropha biodiesel engine

Abstract: Biodiesel plays a major role as one of the alternative fuel options in direct injection diesel engines for more than a decade. Though many feed stocks are employed for making biodiesel worldwide, biodiesel derived from domestically available non-edible feed stocks such as Jatropha curcas L. is the most promising alternative engine fuel option especially in developing countries. Since experimental analysis of the engine is pricey as well as more time consuming and laborious, a theoretical thermodynamic model is necessary to analyze the performance characteristics of jatropha biodiesel fueled diesel engine. There were many experimental studies of jatropha biodiesel fueled diesel engine reported in the literature, yet theoretical study of this biodiesel run diesel engine is scarce. This work presents a theoretical thermodynamic study of single cylinder four stroke direct injection diesel engine fueled with biodiesel derived from jatropha oil. The two zone thermodynamic model developed in the present study computes the in-cylinder pressure and temperature histories in addition to various performance parameters. The results of the model are validated with experimental values for a reasonable agreement. The variation of cylinder pressure with crank angle for various models are also compared and presented. The effects of injection timing, relative air fuel ratio and compression ratio on the engine performance characteristics for diesel and jatropha biodiesel fuels are then investigated and presented in the paper.

Theoretical and experimental investigation of SI engine performance and exhaust emissions using ethanol-gasoline blended fuels

Abstract: In this study, potato waste bioethanol was evaluated as an alternative fuel for gasoline engines. The pollutant emissions and performance of a four stroke SI engine operating on ethanol-gasoline blends has been investigated experimentally and theoretically. In the theoretical study, a quasi-dimensional SI engine cycle model has been adapted for spark ignition engines running on gasoline-ethanol blends. A mathematical model using Matlab software was developed using the first law of thermodynamics and conservation equations to predict the SI engine performance for different blend ratios. The model was also used to evaluate the engine emissions and the mechanical and heat losses in the engine which is not included in this study. Experiments were performed with the blends containing 5, 10, 15 and 20 vol% ethanol. The results show that increasing ethanol-gasoline blended will marginally increase the power and torque output of the engine. For ethanol blends it was found that the brake specific fuel consumption (bsfc) was decreased using 5% and 10% ethanol while the brake thermal efficiency and the volumetric efficiency were increased. Exhaust gas emissions were measured and analyzed for unburned hydrocarbons (UHC), carbon dioxide (CO2), carbon monoxide (CO), Oxygen (O2) and Oxide of Nitrogen NOx at engine speeds ranging from 1000 to 5000 rpm. The concentration of CO and UHC emissions in the exhaust pipe were found to be decreased when ethanol blends were introduced. The concentration of CO2 and NOx was found to be increased when ethanol is introduced. Results obtained from both theoretical and experimental studies were compared. The simulation results have been validated against data from experiments and it results to a good agreement between the trends in the predicted and experimental results.

Multi-part piston for an internal combustion engine and method for its production

Abstract: A method for producing a multi-part piston for an internal combustion engine and the piston itself, which has an upper piston part and a lower piston part, each having an inner and an outer support element, which elements delimit an outer circumferential cooling channel and an inner cooling chamber. The inner support element of the upper piston part and/or the inner support element of the lower piston part have at least one recess on their surface. The upper piston part and the lower piston part are connected with one another by pressure welding.

Variable valve operating apparatus for internal combustion engine

Abstract: Provided is a variable valve operating apparatus for an internal combustion engine, which can favorably reduce electric power consumption in a vehicle system that may stop the internal combustion engine during power-up of the vehicle system. A changeover mechanism 90 is provided which is capable of switching between a connection state in which a first rocker arm 96 and a second rocker arm 98 are in connection with each other via a changeover pin 112, 118 and a disconnection state in which the connection is released. The changeover mechanism 90 performs energization of actuators 130 for each cylinder in a case in which fuel supply to the internal combustion engine 12 is stopped in response to an establishment of a predetermined stop condition. The above-described energization of the actuator 130 for each cylinder is stopped in a case in which a crankshaft 78 of the internal combustion engine 12 stops rotating during an energization time period of the actuator 130 and in which the crankshaft 78 is not driven by an external power.

Variable compression ratio apparatus for vehicle engine

Abstract: A variable compression ratio apparatus for a vehicle engine that is mounted at the engine receiving combustion force of an air-fuel mixture from a piston and rotating a crankshaft mounted between upper and lower cylinder blocks, and that changes compression ratio of the air-fuel mixture by changing a mounting height of the crankshaft according to a driving condition of the engine, may include a bearing having a hollow space eccentric to a center thereof and rotatably mounted between the upper and lower cylinder blocks, the crankshaft being rotatably inserted in the hollow space; and an operating unit provided at the lower cylinder block and controlling a rotational displacement of the bearing.

A Parametric Model for Ionization Current in a Four Stroke SI Engine

Abstract: A model for the thermal part of an ionization signal is presented that connects the ionization current to cylinder pressure and temperature in a spark ignited internal combustion engine. One strength of the model is that, after calibration, it has only two free parameters: burn angle and initial kernel temperature. By fitting the model to a measured ionization signal, it is possible to estimate both cylinder pressure and temperature, where the pressure is estimated with good accuracy. The model approach is validated on engine data. Cylinder pressure and ionization current data were collected on a Saab four-cylinder spark ignited engine for a variation in ignition timing and air-fuel ratio. The main result is that the parametrized ionization current model can be used to estimating combustion properties as pressure, temperature, and content of nitric oxides based on measured ionization currents. The current status of the model is suitable for off-line analysis of ionization currents and cylinder pressure. This ionization current model not only describes the connection between the ionization current and the combustion process, but also offers new possibilities for engine management system to control the internal combustion engine.