Variable Compression Ratio Engine

Engines are widely used to convert chemical energy into mechanical energy for power generation. They can be classified into Spark Ignition and Compression Ignition Engines based on the nature of combustion. In both engine types, air-fuel mixture is compressed before ignition, and the compression ratio determines the extent of compression. Higher compression ratios generally result in increased power output. While several parameters such as fuel-air ratio, valve timing, and spark timing can be controlled to enhance engine performance, there are limited options for dynamically adjusting the compression ratio during engine operation. This research aims to develop a method for modifying the compression ratio of an engine to achieve optimal performance. The proposed approach involves connecting the piston to a primary connecting rod, which, in turn, connects to a first slider joint. The crankshaft is connected to a secondary connecting rod, which is linked to a second slider joint. Both slider joints can slide along a pivoted slider arm, enabling adjustment of the leverage around the pivot point. By employing this variable compression ratio method, it becomes possible to achieve various performance and emission improvements in the engine. Additionally, a single engine can accommodate the combustion of different fuel types such as petrol, diesel, CNG, and hydrogen, among others.

This study applies Closed-Loop Combustion Control (CLCC) using Variable Compression Ratio (VCR) and cylinder balancing using variable lambda to solve the problem. Step changes of set points for combustion phasing, Compression Ratio (CR), and load together with ramps of engine speed and inlet air temperature are investigated. Performances of the controllers are investigated by running the engine at either a constant amount of injected fuel corresponding to an approximate load of 1.5 or 2.5 bar BMEP and/or constant speed of 2000 rpm. Commercial RON 92 gasoline is used in the test. The CLCC is found to be fast and effective and has a potential of handling step changes in a matter of cycles, while the speed and temperature ramps need some more optimization of the CLCC. The CR controller is very fast and has a time constant corresponding to three engine cycles at 2000 rpm.

Objective: In medical image processing, storage and transmission of image pixels is a vital problem since diagnosis is a continuous process. Methods:The 2D maximum entropy method segmentation followed by compression provides good results in the field of Medical image processing which has storage and transmission problems.The proposed algorithm is created using 2-D maximum entropy method segmentation and followed by Hybrid image compression.This proposal introduces an advanced compression method which combines both lossy and lossless image compression techniques. The clinical part of the image is segmented with 2-D maximum entropy thresholding and lossless techniques are applied to compress this part. Lossy image compression technology is implemented in other part of the image that is with the background picture. Run Length Encoding is applied to the resultant data to produce the compressed image. Findings:The Advantage of using 2-D Maximum entropy method is that it considers both the grey information and neighbouring information. It can be able to produce good results even the image's signal to noise ratio (SNR) is low. Among lossy and lossless image compression methods lossless method is preferred in medical image processing since it has to protect important clinical information. Lossless compression can be able to produce lower compression ratio than lossy because it reduces the size of image only to certain limit. The experimental result shows that the proposed method provides good compression ratio and PSNR measures. Novelty/Improvements:Future enhancement of this algorithm is that the neural network algorithm such as selforganizing feature map can be used to find out the threshold value automatically.

Objective : In medical image processing, storage and transmission of image pixels is a vital problem since diagnosis is a continuous process. Methods : The 2D maximum entropy method segmentation followed by compression provides good results in the field of Medical image processing which has storage and transmission problems.The proposed algorithm is created using 2-D maximum entropy method segmentation and followed by Hybrid image compression.This proposal introduces an advanced compression method which combines both lossy and lossless image compression techniques. The clinical part of the image is segmented with 2-D maximum entropy thresholding and lossless techniques are applied to compress this part. Lossy image compression technology is implemented in other part of the image that is with the background picture. Run Length Encoding is applied to the resultant data to produce the compressed image. Findings : The Advantage of using 2-D Maximum entropy method is that it considers bo...

This work presents the achievement of a monitoring, recording, processing and interpretation concept, at laboratory scale, of some functional parameters for a spark-ignition engine, based on an electronic equipment, which measures the values of 17 parameters that describe the operation of an internal-combustion engine. In order to be able to control the optimal operation of an internal-combustion engine, an important parameter that should be measured is the pressure in the combustion chamber, which has high values (50-70 bar), the developed temperature is high and the frequency of appearance is high (depending on the crankshaft's speed). The measured pressure depends on the crankshaft's position. Is used a pressure transducer with strain-gauge socket, and measurement of the crankshaft's position with a speed transducer with variable reluctance. From experimental data, on one hand, can be analyzed the pressure modification in the combustion chamber depending on the crankshaft's position, and on the other hand, the maximum pressure modification in the cylinder depending on the speed.

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The aim of the article is to present and evaluate the results of a internal combustion engine with the Dyno-Max Software and the test bed, which has a high applicability in the field of internal combustion engines and automobiles as well as the peripheral related equipment. For research it was used a Chevy 350 engine with a 350 cubic inch (5.7-liter) small block V8 with a 4.00 and 3.48 inch bore and stroke. The base version of this engine makes 195 horsepower and features an 8.5 compression ratio.

In this paper we propose a method of compression which is Huffman coding based on histogram information and image segmentation. It is used for lossless and lossy compression. The amount of image will be compressed in lossy manner, and in lossless manner, depends on the information obtained by the histogram of the image. The results show that the difference between original and compressed images is visually negligible. The compression ratio(CR) and peak signal to noise ratio(PSNR) are obtained for different images. The relation between compression ratio and peak signal to noise ratio shows that whenever we increase compression ratio we get PSNR high. We can also obtain minimum mean square error. It shows that if we get high PSNR than our image quality is better.

In this paper, the methodology of the measurement of the angular speed of the crankshaft of a ten-cylinder diesel OM403 engine is presented, with regular and irregular engine operation. The angular velocity was measured under laboratory conditions, on already installed measuring equipment from the laboratory and on the break of a well known brand-Schenck, by using an optoelectronic incremental rotary encoder, a data acquisition module and the LabVIEW software for synchronization and management of the measuring equipment. The goal of this paper is to give a practical contribution to researches of measuring of crankshaft angular speed of the crankshaft engine OM 403.

From its inception, the internal combustion engine has evolved in small and sometimes great leaps, driven by constructive, technological and exploitation implementations that have allowed it to meet consumer expectations as well as environmental and fuel consumption regulations. Spark ignited engines have lower performance under low loads compared to Diesel engines, the biggest difference between them being the compression ratio, limited in the first ones by the risk of the detonation occurrence. The introduction of mechatronics developments in spark ignited engines have contributed to their performance improvement through the 5128 Edison Henao Castañeda et al. controlled variation of ignition and valve events (timing and lift), controlled variation of intake manifold length and volume, exhaust gas recirculation, and variable supercharging systems, among other technological strategies. Of all the constructive alternatives, the biggest impact on engine performance lies in compression ratio, and the control of its variation becomes one of the main research goals for engine manufacturers. In this paper, some of the constructive efforts, reported in literature, to obtain mechanisms and systems for the control of compression ratio of internal combustion engines are overviewed, with the main goal of presenting the methodology for the optimized synthesis of a multi-link variable compression ratio mechanism, designed to be assembled in a commercial single cylinder stationary Diesel engine as a fundamental equipment of an octane rating test bench for different fuel blends tested. The synthesis technique presented in the paper develops the range of motion for the six links Stephenson mechanism, applies a method of synthesizing the output slider trajectory, and analyzes the mechanism performance in terms of slider stroke variation range. It is shown that compression ratios resulted from slider variations can be kept between 10 and 17,5, a range sufficient to study commercial engine fuels, a utilitarian goal pursued.

The security of multimedia becomes more important, since multimedia data are transmitted over open networks more frequently. In this modern world, hidden information concept are very important and play a significant role to reducing the space in the memory as well as on disk drives. Compression of the encrypted information has taken more attention due to security reasons from last few years. If encryption and compression of the information works properly then it results to high speed computation. According to practical scenario encryption should be performed before the compression of information. Because unencrypted information have more chances of stealing. And now a day"s data hacker becomes too intelligent to break the encrypted images to get the original contents, so many systems are designed to combine the encryption and compression in single module to provide greater security. Therefore we have proposed system where encryption is done prior to the image compression by ran...

In the course of recent decades, medical imaging has<br> been dominated by the use of costly film media for review and<br> archival of medical investigation, however due to developments in<br> networks technologies and common acceptance of a standard digital<br> imaging and communication in medicine (DICOM) another approach<br> in light of World Wide Web was produced. Web technologies<br> successfully used in telemedicine applications, the combination of<br> web technologies together with DICOM used to design a web-based<br> and open source DICOM viewer. The Web server allowance to<br> inquiry and recovery of images and the images viewed/manipulated<br> inside a Web browser without need for any preinstalling software.<br> The dynamic site page for medical images visualization and<br> processing created by using JavaScript and HTML5 advancements.<br> The XAMPP 'apache server' is used to create a loc...

The utilization of biofuels in IC engines have been increased and trending area of research due to the sustainability of butanol and algae fuels. As these fuels are readily available and the route of production of these fuels is also not limited. Because of the technological advancements and demand of alternative fuels, the operating conditions of IC Engines are becoming stringent, precise and more demanding. Further, it is very well established fact that the emissions of engine depends on the performance of fuel, type of fuel blends and ratio of blending. Therefore, it is more important that the type of fuel or fuel blends may be selected in such a way that it may provide the optimal performance. The review of the available experimental studies shows that the performance and emission characteristics of butanol and algae oil fuel blends with gasoline are limited in SI Engines. Thus, there is need to carry out the experimental studies related to the emissions of butanol and algae oil...

Image encryption has to be conducted prior to image compression. In this paper how to design a pair of image encryption and compression algorithms such that compressing encrypted images can still be efficiently performed. This paper introduced a highly efficient image encryption-then compression (ETC) system. The proposed image encryption scheme operated in the prediction error domain is able to provide a reasonably high level of security. More notably, the proposed compression approach applied to encrypted images is only slightly worse, unencrypted images as inputs. In contrast, most of the existing ETC solutions induce significant penalty on the compression efficiency.

To minimize throttling energy loss, the timing of the on/off valves of a digital displacement motor must consider the pre-compression and de-compression of the compressibe fluid. In this paper, a rotary on/off valve, whose rotation controls the valve timing, is used. The desired motion of the rotary valve that respects the ideal valve timing is a function of, and is periodic with respect to, the motor crank shaft angle. As the desired valve trajectory is not periodic in time unless the motor speed is constant, the conventional internal model based repetitive control is not applicable. A recently developed angle-domain repetitive control is used instead to control the rotary valve motion to achieve the desired valve timing, while exploiting the periodicity of the reference trajectory with respect to crank shaft angle. Experiments show that the proposed controller achieves good tracking performance for a broad range of varying motor speeds. This in turn leads to efficiency gains for t...

Urban traffic involves frequent acceleration and deceleration. During deceleration, the energy previously used to accelerate the vehicle is mainly wasted on heat generated by the friction brakes. If this energy that is wasted in traditional IC engines could be saved, the fuel economy would improve. One solution to this is a pneumatic hybrid using variable valve timing to compress air during deceleration and expand air during acceleration. The compressed air can also be utilized to supercharge the engine in order to get higher load in the first few cycles when accelerating. A Scania D12 single-cylinder diesel engine has been converted for pneumatic hybrid operation and tested in a laboratory setup. Pneumatic valve actuators have been used to make the pneumatic hybrid possible. The actuators have been mounted on top of the cylinder head of the engine. A pressure tank has been connected to one of the inlet ports and one of the inlet valves has been modified to work as a tank valve. The goal has been to test and evaluate 2 different modescompression mode (CM) where air is stored in an air tank during deceleration and air-motor mode (AM) where the previously stored pressurized air is used for accelerating the vehicle. This paper also includes an optimization of the CM.

Crank shaft torsional vibration has impact on the crank angle measurement accuracy in large-bore Internal Combustion Engines (ICE). In large bore engine, the torsional vibration angular displacement can be up to 1 degree, which in turn can cause a fault of 2 bar in Indicated Mean Effective Pressure (IMEP) and a fault of 0.6 degrees in the Crank Angle of 50% burned (CA50). IMEP and CA50 are critical feedback parameters for closed-loop combustion control, therefore to compensate torsional vibration effect in real-time engine control system can not only provide higher accuracy crank angle data but especially improve the combustion analysis and closed-loop control accuracy. Thus, in this work, a torsional vibration dynamic model is established to improve the accuracy of the crank angle measurement. A lumped parameter model of torsional vibration is established for a Wärtsilä engine, the numerical computing method is determined, harmonic analysis is applied, the Transfer Matrix Method (TMM) result is verified with flexible Multibody Simulation (MBS) calculation and the accuracy of the torsional vibration model is estimated. For the trial of online crank angle correcting, the computation time of this model was found to be around 300 to 400 times heavier as IMEP calculation. A direct IMEP correcting model based on a linear dependence of cylinder number with an accuracy of ±0.1 bar compared with the reference was proposed. Based on all those results, it is concluded that the TMM method can calculate the angular displacement from torsional vibration with high accuracy and correct the crank angle measurement from cylinder-wise and crank angle wise, and the torsional vibration calculation resolution needs to be considered based on performance and calculation capacity.

With the tightening requirements on engine emission and performance, pressure based combustion controls are becoming common in medium speed large bore reciprocating internal combustion engines. The accuracy of the cylinder pressure data including the raw pressure value at its corresponding crank angle, has a vital impact on engine controllability. For instance, this work shows that a 1-bar pressure offset leads to a 0.7% variation in the total heat release (THR) while the 50% heat release crank angle (CA50) can be shifted by 2 degrees. Similarly, with a single degree error in the crank position, the indicated mean effective pressure (IMEP) gets a 1.5% error. Thus, in this work the typical errors for cylinder pressure measurement are reviewed and analyzed for large bore four stroke marine and power plant production engines. The main sources of error for pressure measurement are thermal shock and installation defects. Meanwhile, calibration is carried out for ten production pressure transducers to provide a general accuracy result of the pressure transducers that are used in production engines. The main sources of error for crank angle position monitoring-when done with a flywheel-based inductive system, manufacturing tolerance, installation, and the relative displacement between the pickups and the shaft due to shaft bending, shaft longitudinal movement, torsional vibration and engine block vibration are the main sources of error. In this paper, those errors are quantified individually through simulation and their impacts on IMEP and CA50 are also presented. At last, cylinder volume deformation and its impact on combustion diagnostics are also estimated. From the result it is concluded that torsional vibration and cylinder volume deformation have the most significant effects for combustion analysis.

This paper describes an inertial dynamometer system which has been applied to the testing of small two-stroke kart racing engines. The dynamometer incorporates a flywheel of appropriate moment of inertia to simulate the mass of a kart and driver. The test procedure involves measurement of the flywheel speed during an acceleration phase resulting from opening the throttle. Calculation of the instantaneous flywheel acceleration corresponding to each engine speed directly gives a measure of the torque and power characteristics. Performance results, including exhaust pressure traces, are presented from a series of tests conducted on a 100 cm 3 kart engine. The results are compared with corresponding steady state measurements recorded on an eddy current dynamometer. In addition, the measured results are compared with predictions from a computer simulation.

Urban traffic involves frequent acceleration and deceleration. During deceleration, the energy previously used to accelerate the vehicle is mainly wasted on heat generated by the friction brakes. If this energy that is wasted in traditional IC engines could be saved, the fuel economy would improve. One solution to this is a pneumatic hybrid using variable valve timing to compress air during deceleration and expand air during acceleration. The compressed air can also be utilized to supercharge the engine in order to get higher load in the first few cycles when accelerating. A Scania D12 single-cylinder diesel engine has been converted for pneumatic hybrid operation and tested in a laboratory setup. Pneumatic valve actuators have been used to make the pneumatic hybrid possible. The actuators have been mounted on top of the cylinder head of the engine. A pressure tank has been connected to one of the inlet ports and one of the inlet valves has been modified to work as a tank valve. The goal has been to test and evaluate 2 different modescompression mode (CM) where air is stored in an air tank during deceleration and air-motor mode (AM) where the previously stored pressurized air is used for accelerating the vehicle. This paper also includes an optimization of the CM.

This chapter presents the possibility of use of the pneumatic piston engine with twostroke cycle or four stroke-cycle of the work as an alternative driving source or additional power for the battery regeneration in the electric vehicles. Additionally, such engine can work together with combustion engine as a drive unit in a road vehicle. During city driving, such engine is driven by compressed air. The energy for the engine work is taken from the energy of the air stored at high pressure (about 30 MPa) in bottles or tanks. The chapter presents the thermodynamic theory included in the mathematical model of the engine based on thermodynamic processes (mass and energy balance). On such considerations, the chapter shows the results obtained from specially written computer program for the determination of the most important factors. The results of the calculations are included in the graphs showing the influence of the control parameters (air pressure, injection timing and rotational speed) on the engine working parameters. Certain chapters concern to a hybrid combustion system with an air injection only for a compression ignition engine in order to achieve higher indicated mean pressure and lower fuel consumption.

Compression is the science and art of representing the information in a compact form rather than its original or uncompressed form in data storage or transmission. Data compression is storing data in a format that requires less space than usual. Nowadays, data compression is a common requirement in telecommunication industry. Since last few decades, the research is continuing in the field of compression and various data compression techniques are already developed to compress different data formats. But, a data compression program using strange number system (specially using pentaoctagesimal SNS) tries to compact the data in some special format, such that the data occupies less disk space or that it can be transmitted in less time. A decompression program restores the information again. This paper mainly describes a simple compression and decompression process which is free from time complexity.

By increasing the volume of telemedicine information, the need for medical image compression has become more important. In angiographic images, a small ratio of the entire image usually belongs to the vasculature that provides crucial information for diagnosis. Other parts of the image are diagnostically less important and can be compressed with higher compression ratio. However, the quality of those parts affects the overall understanding of the image as well. Existing methods compress foreground and background of angiographic images using different techniques. In this paper, we first utilize a convolutional neural network to segment vessels and then represent a hierarchical block processing algorithm capable of both eliminating the background redundancies and preserving the overall visual quality of angiograms.

Advanced microscopic techniques such as high-throughput, high-content, multispectral, and 3D imaging could include many images per experiment requiring hundreds of gigabytes (GBs) of memory. Efficient lossy image-compression methods such as joint photographic experts group (JPEG) and JPEG 2000 are crucial to managing these large amounts of data. However, these methods can get visual quality with high compression ratios but do not necessarily maintain the medical data and information integrity. This paper proposes a novel and improved medical image compression method based on color wavelet difference reduction. Specifically, the proposed method is an extension of the standard wavelet difference reduction (WDR) method using mean co-located pixel difference to select the optimum quantity of color images that present the highest similarity in the spatial and temporal domain. The images with large spatiotemporal coherence are encoded as one volume and evaluated regarding the peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM). The proposed method is evaluated in the challenging histopathological microscopy image analysis field using 31 slides of colorectal cancer. It is found that the perceptual quality of the medical image is remarkably high. The results indicate that the PSNR improvement over existing schemes may reach up to 22.65 dB compared to JPEG 2000. Also, it can reach up to 10.33dB compared to a method utilizing discrete wavelet transform (DWT), leading us to implement a mobile and web platform that can be used for compressing and transmitting microscopic medical images in real time.

Advanced microscopic techniques such as high-throughput, high-content, multispectral, and 3D imaging could include many images per experiment requiring hundreds of gigabytes (GBs) of memory. Efficient lossy image-compression methods such as joint photographic experts group (JPEG) and JPEG 2000 are crucial to managing these large amounts of data. However, these methods can get visual quality with high compression ratios but do not necessarily maintain the medical data and information integrity. This paper proposes a novel and improved medical image compression method based on color wavelet difference reduction. Specifically, the proposed method is an extension of the standard wavelet difference reduction (WDR) method using mean co-located pixel difference to select the optimum quantity of color images that present the highest similarity in the spatial and temporal domain. The images with large spatiotemporal coherence are encoded as one volume and evaluated regarding the peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM). The proposed method is evaluated in the challenging histopathological microscopy image analysis field using 31 slides of colorectal cancer. It is found that the perceptual quality of the medical image is remarkably high. The results indicate that the PSNR improvement over existing schemes may reach up to 22.65 dB compared to JPEG 2000. Also, it can reach up to 10.33dB compared to a method utilizing discrete wavelet transform (DWT), leading us to implement a mobile and web platform that can be used for compressing and transmitting microscopic medical images in real time.

This chapter presents the possibility of use of the pneumatic piston engine with twostroke cycle or four stroke-cycle of the work as an alternative driving source or additional power for the battery regeneration in the electric vehicles. Additionally, such engine can work together with combustion engine as a drive unit in a road vehicle. During city driving, such engine is driven by compressed air. The energy for the engine work is taken from the energy of the air stored at high pressure (about 30 MPa) in bottles or tanks. The chapter presents the thermodynamic theory included in the mathematical model of the engine based on thermodynamic processes (mass and energy balance). On such considerations, the chapter shows the results obtained from specially written computer program for the determination of the most important factors. The results of the calculations are included in the graphs showing the influence of the control parameters (air pressure, injection timing and rotational speed) on the engine working parameters. Certain chapters concern to a hybrid combustion system with an air injection only for a compression ignition engine in order to achieve higher indicated mean pressure and lower fuel consumption.

A systematic study to determine the effect of varying the compression ratio on the performance of a diesel engine is carried out. In this paper the various performance parameters have been studied at various compression ratios and optimum value of compression ratio has been found. At this value the engine performs at its best efficiency and lowest fuel consumption. The entire study was carried out using a simulation software Diesel RK version 4.1.3.143. In order to find out the optimum compression ratio the simulation was carried out at the compression ratios ranging from 17:1-21:1. The performance parameters considered for the simulation are Indicated mean effective pressure (IMEP), [1] Indicated Efficiency, Brake mean effective pressure (BMEP), Braking efficiency, Specific fuel consumption (SFC) and Exhaust gas temperature. The graphs for these parameters against the engine speed at different compression ratios are plotted. The results shows that engine works best at compression ratio 18.5 for the above stated parameters.

In this paper, a medical image compression model for efficient transmission of medical images using block BWT-MTF with Huffman encoding and hybrid fractal encoding is proposed. Diagnosis of medical images requires detailed analysis of vital portions of the image. In medical image compression, a small loss in the vital portion leads to wrong interpretation. The proposed compression scheme will eliminate this hindrance by utilizing region based compression which results in the lossless compression of requisite area, where the salient details are stored and lossy compression in the remaining region. In this method, region which contains most required diagnostic features is separated and then encoded without significant loss in diagnostic quality using block based Burrows-Wheeler compression algorithm. Remaining regions are encoded using hybrid fractal encoding algorithm. Finally both encoded region are combined together to reconstruct the output image. The performance of the compression scheme is evaluated in terms of PSNR, CR, space saving and time consumption. The numerical result shows that the proposed method gives better results compared to the conventional methods in terms of PSNR better results obtained for ultra sound and MRI images with average value of 36.166 db and 34.097 db respectively.

From its inception, the internal combustion engine has evolved in small and sometimes great leaps, driven by constructive, technological and exploitation implementations that have allowed it to meet consumer expectations as well as environmental and fuel consumption regulations. Spark ignited engines have lower performance under low loads compared to Diesel engines, the biggest difference between them being the compression ratio, limited in the first ones by the risk of the detonation occurrence. The introduction of mechatronics developments in spark ignited engines have contributed to their performance improvement through the 5128 Edison Henao Castañeda et al. controlled variation of ignition and valve events (timing and lift), controlled variation of intake manifold length and volume, exhaust gas recirculation, and variable supercharging systems, among other technological strategies. Of all the constructive alternatives, the biggest impact on engine performance lies in compression ratio, and the control of its variation becomes one of the main research goals for engine manufacturers. In this paper, some of the constructive efforts, reported in literature, to obtain mechanisms and systems for the control of compression ratio of internal combustion engines are overviewed, with the main goal of presenting the methodology for the optimized synthesis of a multi-link variable compression ratio mechanism, designed to be assembled in a commercial single cylinder stationary Diesel engine as a fundamental equipment of an octane rating test bench for different fuel blends tested. The synthesis technique presented in the paper develops the range of motion for the six links Stephenson mechanism, applies a method of synthesizing the output slider trajectory, and analyzes the mechanism performance in terms of slider stroke variation range. It is shown that compression ratios resulted from slider variations can be kept between 10 and 17,5, a range sufficient to study commercial engine fuels, a utilitarian goal pursued.

Most commonly, image encryption has to be conducted prior to image compression. This has led to the problem of how to design a pair of image encryption and compression algorithms such that compressing the encrypted images can still be efficiently performed. is a highly efficient image encryption-then-compression (ETC) system. The proposed image encryption scheme operated in the prediction error domain can able to provide a high level of security. An arithmetic coding-based approach can be used to efficiently compress the encrypted images. Most of the existing ETC solutions induce significant penalty on the compression efficiency. Image hiding approach after the encryption phase is also used for getting more security. Gradient Adjusted Predictor (GAP) is used to find predicted values of the image. Keywords— Gradient Adjusted Predictor, Encryption then Compression, Compression then Encryption

Compressed air engine (CAE) is divided into two types. First type is the fabricated CAE for mobile vehicle and the second type is the retrofitting of compressed air into Spark Ignition Engine and most researches are concentrating on the second type. Retrofit CAE researches use a fixed camshaft lobe as in spark ignition engine. This will make the separation angle between inlet valves open and exhaust valve open fixed and between inlet valves close and exhaust valve close fixed. The purpose of this thesis is to design and develop a CAE that uses an independent valve timing and duration setting of inlet and outlet valves of a compressed air engine in order to identify the best valve timing and duration. This was done by controlling the different angles of valve timing for inlet and outlet compressed air using solenoid valves. Compressed air was fed into the CAE with a certain pressure. The brake power was applied slowly by using a Prony Brake. The different configurations settings of p...

The probabilistic inference of current Probabilistic Logic Programming systems uses weighted model counting (WMC). To compute the success probability of a query, first the set of proofs of the query is computed. Next, the set of proofs is converted into a corresponding Boolean formula which is compiled into a suitable representation that allows WMC in polynomial time. The computational cost of each step depends on the size and the complexity of the output of the previous step. The set of proofs, computed in the first step, can become large. In this paper we propose a way to reduce the size of the collected proofs in order to improve the next steps. We use an AND-OR graph to represent the collected proofs. Our method compacts the AND-OR graph by detecting several patterns and applying transformations on them. Experiments confirm that by decreasing the size of the AND-OR graph, we reduce the time and memory consumption of the next steps. Our algorithm enables probabilistic inference o...

Multi-process working principle is one of the modern approaches to development of internal combustion engines. By combining the original features of the Otto and Diesel working processes, an improvement of the engine efficiency and ecological characteristics can be achieved. Examples for that are spark ignition engine with stratified charge as well as compression ignition engines with homogeneous charge. The experimental multi-process engine was developed as well as testing methodology, for the basic researches efficiency and ecological characteristics of the Otto/Diesel engine. This paper presents the results of the combination of Otto/ /Diesel working processes when the engine working with both conventional and bio-fuels. Results of initial tests of Otto/Diesel engine show a high potential to reduce particulate emissions. The investigation has shown certain disadvantages of the engine and the ways for theirs overcoming.

The limited quantities of oil reserves and the exhaust emissions from IC engines have become a threat to the existence of IC engines. One of the best solutions to the problem is the use of alternative fuels. Hydrogen is an alternative fuel that is called a fuel of the future. A disadvantage of hydrogen is its high combustion speed. Experimental results were used for the determination of inputs for numerical analysis. The numerical analysis is performed for a 3D model of the engine in order to determine the working parameters of the engine (pressure and temperature). The main goal of this study is to investigate a possibility of modifying the diesel engine so that it can run on hydrogen. It was found that in such an engine the greatest loads occur in the combustion chamber; thus, the vital parts of the engine are protected. Therefore, a mechanical analysis of the combustion chamber was performed (calculation of stresses and deformations). The obtained results are encouraging because they indicate that by applying the presented solution a much cheaper technology than the modern diesel engine systems is made possible.

The volumetric efficiency significantly influences engine output. Both design and dimensions of an intake and exhaust system have large impact on volumetric efficiency. Experimental equipment for measuring of airflow through the engine, which is placed in the intake system, may affect the results of measurements and distort the real picture of the impact of individual structural factors. This paper deals with the problems of experimental determination of intake airflow using orifice plates and the influence of orifice plate diameter on the results of the measurements. The problems of airflow measurements through a multi-process Otto/Diesel engine were analyzed. An original method for determining volumetric efficiency was developed based on in-cylinder pressure measurement during motored operation, and appropriate calibration of the experimental procedure was performed. Good correlation between the results of application of the original method for determination of volumetric efficiency and the results of theoretical model used in research of influence of the intake pipe length on volumetric efficiency was determined.

A zero-dimensional, one zone model of engine cycle for steady-state regimes of engines and a simplified procedure for indicator diagrams analysis have been developed at the Laboratory for internal combustion engines, fuels and lubricants of the Faculty of Mechanical Engineering in Kragujevac. In addition to experimental research, thermodynamic modeling of working process of diesel engine with direct injection has been presented in this paper. The simplified procedure for indicator diagrams analysis has been applied, also. The basic problem, a selection of shape parameters of double Vibe function used for modeling the engine operation process, has been solved. The influence of biodiesel fuel and engine working regimes on the start of combustion, combustion duration and shape parameter of double Vibe was determined by a least square fit of experimental heat release curve.

Image compression is one of the most important step in image transmission and storage. Most of the state-of-art image compression techniques are spatial based. In this paper, a histogram based image compression technique is proposed based on multi-level image thresholding. The gray scale of the image is divided into crisp group of probabilistic partition. Shannon's Entropy is used to measure the randomness of the crisp grouping. The entropy function is maximized using a popular metaheuristic named Differential Evolution to reduce the computational time and standard deviation of optimized objective value. Some images from popular image database of UC Berkeley and CMU are used as benchmark images. Important image quality metrics-PSNR, WPSNR and storage size of the compressed image file are used for comparison and testing. Comparison of Shannon's entropy with Tsallis Entropy is also provided. Some specific applications of the proposed image compression algorithm are also pointed out.

The medical image compression plays an important role in digital image compression. Compression reduces the redundancy and encodes the data. To use different techniques and algorithms we can get the desired result. But it will depend on the used algorithm, which algorithm we have used in which circumstances. In this paper we have used SPIHT method with wavelet bior4.4 on brain surface medical image with different type of image parameters. And observe the result of this method with different types of image parameters at different level of iterations.

In recent years, there have been considerable improvements in approaches and models for processing of multimedia data. Several avenues have been taken by these improvements, including improved representation, interpretation and so on. New methods have been created to reduce the size of multimedia data, which is a technical advancement. These algorithms are particularly useful in a variety of applications, such as a data storage system for multimedia data, among others. The compression process is the term used to refer to the process of reducing the size of data informally. In computing, compression is the process of presenting data in a more compact format. The term "compression" refers to the process of compressing data, which includes source coding, data compression, bandwidth compression, and signal compression. An image, a video, or an audio signal can all be referred to as a signal in this context. However, in this work, we limit our discussion to medical images. 1.2 Image Compression The image compression is a process of reducing irrelevance 75% MATCHING BLOCK 1/30 Divya, Mtech, CS.docx (D28245818) and redundancy of the image data in order to be able to store or transmit data in an efficient form. There are three types of redundancies present in the image. 1 ? Coding Redundancy: When few bits use to representing frequently occurred information in the image. To represent an image, pixel values of the image are used as symbols. These symbols are called as codes. The code word is a sequence of code which is assigned to each pixel values of the image. This type of code is always reversible and usually implemented using look-up tables (LUT) method. ? Inter-pixel Redundancy: It is related to the correlation between the neighboring pixels in the image. It is also called spatial redundancy. Here, the information carried by an individual pixel is almost related to its nearest pixels. ? Psycho-visual Redundancy: This redundancy is because of ignoring data by human visual system (HVS). The quantization process is used to reduce psycho-visual redundancy. 1.3 Data Compression Model The general block diagram of the image data compression model is given in Figure 1.1 [157]. This model consists of two blocks such as encoder and decoder. Here, an image I (x, y) is fed to an encoder which converts images into a set of symbols. After transmission over the channel, the encoded symbols are fed to decoder, where a reconstructed output image I′(x, y) is generated. If the system is error-free, no distortion will occur in the reconstructed output image; if it is not, some distortion will emerge in the reconstructed output image. In Figure 1.1, encoder and decoder have two relatively independent blocks. The encoder is composed of two components: a source encoder and a channel encoder. The 2 source encoder eliminates redundant inputs, whereas the channel encoder improves the noise immunity of the source encoder's output. In an ideal world, no channel encoder or decoder is needed. In this instance, the source encoder and decoder are renamed encoder and decoder. Figure 1.1 Generalized block diagram of image compression model Figure 1.2 Source encoder model 3 The source encoder is used to remove redundancy from an input image. The source encoder process may be described as a sequence of three distinct processes. The simple block diagram of source encoder is given in Figure 1.2 [157].

Image pressure is strategy to push off the excess data from the photo with the goal that best fundamental insights might be put away to decrease the capacity estimate, transmission transfer speed and transmission time. The basic measurements is separated by methods for differing changes methodologies to such an extent that it can be reproduced without losing top notch and data of the picture. On this theory work similar assessment of picture pressure is finished by four change technique, which may be Discrete Cosine change (DCT), Discrete Wavelet change (DWT) change and fractal coding. MATLAB programs had been composed for each of the above method the well-known JPEG favored is broadly used in advanced cameras and net based absolutely picture transport [3]. The wavelet change, that is a piece of the new JPEG 2000 favored, cases to limit a portion of the outwardly diverting ancient rarities that could show up in JPEG previews. Fractal pressure has furthermore demonstrated guarantee a...

Engine performance is a function of the mileage of the engine. As the number of years of usage increases, the performance of the engine also reduces due to a number of factors like mechanical losses and wear and tear. This was the primary assumption made by the authors and testing was done to validate this statement. The aim of the paper is to validate the primary assumption, quantify the power loss due to an increase in mileage and finally enumerate the factors that have led to the power loss. This paper stresses on the importance of proper maintenance engine maintenance by proving that there are considerable losses even in well-maintained engines. Thus the au- thors believe that this paper is an important contribution to the field of automotive service and maintenance.

The exhaust gas emission control, together with the demand for specific fuel oil consumption reduction, poses a challenge for constructors. As a possible solution a very accurate fuel injection and combustion process control is considered. Such a control needs a precise timing and synchronization with every piston movement. The understanding of crankshaft deformation phenomena seems to be essential. In this work the experimental methodology of the crankshaft twist angle determination has been presented. The method is based on the cylinder pressure signal and an incremental encoder signal analysis. The presented results show the mean value of crankshaft twist angle under load. The momentary values are presented, too.

NASA Technical Memorandum 81662, 1981
by Phillip R. Meng, W.J. Rice, Harold J. Schock
44 pages

Engine: Mazda 12A

> Content ...
> Summary  3
> Statement of problem  5
> Equipment + test procedure  6
> Definition + basic equations  8
> Real time IMEP measurement system  10
> Results + discussion  15
> Summary + conclusions  17
> Appendix A - Correlator circuit description  19
  » Error averaging  21
  » Power supply  24
  » Calibration  24
> References  26
> Tables  28
> Figures  31

german keywords: Wankelmotor / Kreiskolbenmotor
English Keywords: Wankel Engine / Wankel Rotary Engine / Rotary Piston Engine / Rotary Combustion Engine

A systematic study to determine the effect of varying the compression ratio on the performance of a diesel engine is carried out. In this paper the various performance parameters have been studied at various compression ratios and optimum value of compression ratio has been found. At this value the engine performs at its best efficiency and lowest fuel consumption. The entire study was carried out using a simulation software Diesel RK version 4.1.3.143. In order to find out the optimum compression ratio the simulation was carried out at the compression ratios ranging from 17:1-21:1. The performance parameters considered for the simulation are Indicated mean effective pressure (IMEP), [1] Indicated Efficiency, Brake mean effective pressure (BMEP), Braking efficiency, Specific fuel consumption (SFC) and Exhaust gas temperature. The graphs for these parameters against the engine speed at different compression ratios are plotted. The results shows that engine works best at compression ratio 18.5 for the above stated parameters.

Telemedicine applications allow the patient and doctor to communicate with each other through network services. Several medical image compression techniques have been suggested by researchers in the past years. This review paper offers a comparison of the algorithms and the performance by analysing three factors that influence the choice of compression algorithm, which are image quality, compression ratio, and compression speed. The results of previous research have shown that there is a need for effective algorithms for medical imaging without data loss, which is why the lossless compression process is used to compress medical records. Lossless compression, however, has minimal compression ratio efficiency. The way to get the optimum compression ratio is by segmentation of the image into region of interest (ROI) and non-ROI zones, where the power and time needed can be minimised due to the smaller scale. Recently, several researchers have been attempting to create hybrid compression algorithms by integrating different compression techniques to increase the efficiency of compression algorithms.