Variable Compression Ratio Engine Research Articles

Research and development of new variable compression ratio (VCR) engine mechanism (2nd Report, Dynamics analysis and vibration experiment of VCR engine mechanism)

In order to improve the efficiency of combustion engines, variable compression ratio (VCR) engine is researched. VCR engine changes the compression ratio according to its mechanical configuration. One of the solutions to construct VCR engine is the multi-link type. Multi-link type has an advantage for reducing high order shaking force which is the source of mechanical vibration. Since piston motion strongly influences shaking force, it is required to make the piston displacement profile close to sine curve. However, conventional combustion engine is designed based on four-link piston crank mechanism. Because of the design constraint due to four-design parameters regarding the four-link piston crank mechanism, piston displacement profile diverges from sine curve. In order to solve this problem, six-link piston crank mechanism is applied to VCR engine. Since six-link piston crank mechanism has six-design parameters, the piston displacement profile becomes closer to sine curve than that of the four-link piston crank mechanism. A Stephenson type six-link piston crank mechanism whose constitute four-bar mechanism is the double-crank mechanism is newly designed. And, this mechanism is applied to VCR engine model. We want to put this VCR engine model to practical use. We show basic characteristic of mechanical vibration. First, we measure frame displacement of VCR engine model when the compression ratio vary high compression ratio. Next, we compare frame displacement of VCR engine model with frame displacement of four-link engine model. As a result, tendency of basic characteristic of mechanical vibration almost equate to tendency of dynamics analysis.

Influence of Injection Strategy on B20MOME Fueled CRDI Engine with Toroid Shaped Piston Cavity

New technologies in the fuel injection system have improved the performance of the CI engine. Even though the biodiesel is universally accepted as a suitable alternate fuel for the CI (compression ignition) engine, there have been limited study reported on its utilization for single cylinder CRDI (common rail direct injection) engine. Use of biodiesel with diesel in a CRDI engine reduces proportionate consumption of diesel. In the present study, performance and combustion tests were carried out with the CRDI engine using the B20 blend of mahua methyl ester in diesel on volume basis called (B20 MOME). This study was conducted on a CRDI converted variable compression ratio engine with toroidal shaped cavity in the piston adopted. The tests were carried out at three injection pressures of 400 bar, 600 bar and 800 bar and for three injection timings of 15° BTDC, 20°BTDC and 25°BTDC, respectively. The results of the combustion and performance tests with the CRDI engine were compared with the performance of a CI engine at specified operating conditions with mechanical injection system using diesel as the fuel. The results indicated significant increase in the performance of the engine with increase of injection pressure. At 800 bar injection pressure, brake thermal efficiency of 29.98%, 27.61%, and 26.98% was attained at 15BTDC, 20BTDC and 25BTDC, injection timing respectively using B20 MOME.

Multi-Objective Pareto Robust Design of PID Controllers for Variable Compression Ratio Engines Using Genetic Algorithms

Modern automobile engines must satisfy the challenging and often conflicting goals of minimizing exhaust emissions, providing increased fuel economy and satisfying driver performance requirements over a wide range of operating conditions. An innovative mechanical design approach to achieve these goals has been the development of variable compression ratio (VCR) engines. A challenge with this new engine design is that the compression ratio has a direct influence on the output torque. This is a problem because the engine driver can feel it as a jerk in the movement. Therefore, in order to fully take the advantage of benefits of this engine design it is necessary to have some sort of torque control that can keep a constant torque regardless of changes in compression ratio. In this work a control-oriented engine model is developed to represent a variable compression ratio engine over a range of operating conditions. The model is validated with some available experimental data. Based on the mode, a robust PID controller is optimally designed to control the output torque for the step changes of compression ratio in the presence of parametric uncertainties.

Optimization of compression ignition engine fueled with diesel - chaulmoogra oil - diethyl ether blend with engine parameters and exhaust gas recirculation

This study investigates the performance, combustion and emission characteristics of diesel (D)/straight vegetable oil (SVO)/diethyl ether (DEE) blend in a variable compression ratio engine (VCR), variable engine speed direct injection compression ignition (CI) engine. The compression ratio (CR), speed (N), and load (L) were taken as input factors for the diesel engine optimization. This investigation is done through a combination of experimental data analysis and artificial neural network (ANN) modeling. The response surface methodology (RSM) optimization concerned to minimize the engine emissions and maximize the engine performance. Three optimization works were conducted for 65% D+25% SVO+10% DEE blend, in optimization-1 (opti-1) considered 0% exhaust gas recirculation (EGR), Opti-2 considered 5% EGR and Opti-3 considered 10% EGR. Compared to diesel, carbon monoxide (CO), oxides of nitrogen (NOx), and hydrocarbon (HC) were reduced by 12.8%, 4.19% and 9.61% respectively for blend fuel in opti-2.

Energy and exergy analysis on variable compression ratio multi-fuel engine

The present work emphasis on to estimate the theoretical findings of energy and exergy analysis of biodiesel fueled with diesel on variable compression ratio engine at various combinations of fuel blend at different compression ratios. This study aims to identify the optimum engine settings based on compression ratio and biodiesel blends. The engine is operated with methyl esters of rubber seed oil and its 20, 40, 60 and 80% blends with diesel on volume basis. The compression ratio is varied from 18:1 to 22:1 at five compression ratios at 80% load in 3.5 kW, 1500 rpm, single cylinder water-cooled direct injection engine. The variables analyzed are energy and exergy potential of fuel input, shaft work, cooling water, maximum pressure, heat release rate, exergy destruction, brake-specific energy consumption, brake thermal efficiency, second law efficiency, entropy generation, exhaust gas temperature and various emissions. It is observed that the combination of CR 20, B20 and B40 at 80% load gives a better performance in thermodynamic analysis of methyl esters of rubber seed oil blended with diesel in VCR engine.

Effect of Spark Plug Alteration on Performance Using Hydrogen Enriched Gasoline in Si Engine Under Various Loads and Compression Ratios

In this study, change in brake power (BP) of a variable compression spark ignited engine was investigated with different spark plugs and hydrogen enrichment. The tests were carried out with a four stroke, single cylinder, naturally aspirated, variable compression ratio (VCR) engine. Two different compression ratios (CR) of 8.5:1 and 10:1 under %50 part throttle condition were implemented throughout the experiments. Moreover, engine loads of 8 Nm, 13 Nm and 17 Nm were applied to evaluate effects of different spark plugs and hydrogen usage at different engine loads. Copper, iridium and platinum spark plugs were tested for each experiment condition. In addition, hydrogen was added through the intake manifold with flow rates of 0, 2 and 4 lit/min to enhance combustion of VCR engine. According to test results, iridium and platinum spark plug usage, hydrogen addition and higher compression ratio improved BP significantly. This variance occurred more obvious with platinum spark plug usage comparing to iridium spark plug. In addition, effects of spark plug alteration, hydrogen addition and higher CR on enhancement of BP were comparatively lower at higher engine loads.

Kinematics of a variable stroke and compression ratio mechanism of an internal combustion engine

The development of automotive propulsion has been guided in recent years by policies for the reduction of pollutant emissions. To comply with the imposed regulations, engine adaptability is one of the most effective strategies for meeting efficiency requirements in the case of the diverse operational conditions found in urban traffic. A variable stroke and compression ratio engine is the solution to this requirement. In addition to its advantages, its design inevitably increases the engine’s complexity. Thus, it is necessary to conduct studies on the feasibility of such a technology. This work describes a variable stroke and compression ratio engine mechanism and presents a developed kinematic model that is used to evaluate the requirements for the implementation of this mechanism. The results of the evaluation confirm the possibility of using this alternative mechanism to obtain a higher efficiency in internal combustion engines.

Performance Characteristics of A Variable Compression Ratio Engine using Transesterified Mahua Oil

Performance Characteristics of A Variable Compression Ratio Engine using Transesterified Mahua Oil

Relative Change in SI Engine Power and Economy with Variable Valve Timing: Simulation and ANOVA Analysis

In this research, a comparison between the performance of Ricardo E6/T variable compression ratio engine was conducted at constant and variable valve timing. This was done at three different speeds. The inlet and exhaust valves timing was varied and the performance was tested using specialized software. Results showed strong dependency of engine power and economy on valve timing and lift for all speeds. Further, higher lifts and durations are favorable for good power and the opposite are favorable for good economy. Valve overlap is affecting the engine power and economy in opposite direction as other factors.

Performance Characteristics of a Spark Ignited Variable Compression Ratio Engine at Erratic Loads

Performance Characteristics of a Spark Ignited Variable Compression Ratio Engine at Erratic Loads

Empirical performance analysis of VCR engine fuelled with karanja oil and various additives using ANOVA technique

ABSTRACTIn this present paper, an experimental study is carried out on a single cylinder, four-stroke variable compression ratio (VCR), direct injection diesel engine to analyse the performance characteristics of 20% karanja oil (B20) with diethyl ether, methanol and ethanol as an additives by substituting 5% and 10%, respectively. The engine is operated at the speed of 1500 rpm with VCRs 17 and 18. Analysis of performance parameters such as brake power, indicated power, brake thermal efficiency, mechanical efficiency, specific fuel consumption and indicated thermal efficiency are arrived by the IC engine analysis software which has been coupled with the VCR engine. The outcome data of these blends are to be compared with the ordinary diesel. The results are optimised by using the design of experiments (DOE) method in MINITAB 17.0 software to find out the suitable blend for the engine.

The influence of charge air temperature and exhaust gas recirculation on the availability analysis, performance and emission behavior of diesel - bael oil - diethyl ether blend operated diesel engine

In this work, the first and second laws of thermodynamic analyses were carried out on Kirloskar direct injection, variable compression ratio (VCR) engine at four different charge air temperatures (CAT) and exhaust gas recirculation (EGR) mode. Performance, emission and combustion characteristics along with exergy analysis of ternary test fuel of 60 % diesel + 30 % bael oil + 10 % diethyl ether (DEE) were performed. Various exergy components are identified and calculated individually with the percentage of engine load at 1500 rpm. When operating the diesel engine with 47 °C CAT, brake thermal efficiency (BTE) is improved to 29.33 %, carbon monoxide (CO), hydrocarbon (HC), and emissions have been reduced by 8.57 %, 4.28 % and 6.01 % at peak engine load. The oxides of nitrogen (NOx) have been reduced by 20.12 % at 100 % engine load for 30 % EGR mode. The maximum exergy efficiency of 54.61 % has been observed at full engine load for the 47 °C CAT.

Some studies on mathematical modeling and dynamic stress analysis of a variable compression ratio diesel engine crankshaft

The objective of the present work is to investigate the induced stress and deformation of a crank shaft. For this purpose, Variable Compression Ratio (VCR) engine is tested at 16.5 compression ratio. Peak pressures were recorded at various crank angles. A Matlab code is generated for dynamic analysis. For structural analysis and factor of safety, a three dimensional model crank shaft was developed using solid works. Finite element analysis of AISI E4340 Forged steel and Aluminum alloy 7076-T6 materials are carried by using analysis software ANSYS. The obtained results are equivalent Von-Mises stress, total deformation and factor of safety at different crank angles for the two materials are analyzed. It is concluded that Aluminum alloy exhibits better results than forged steel.

다양한 가변 압축비 엔진 기구의 기구학적 구조 분석

다양한 가변 압축비 엔진 기구의 기구학적 구조 분석

Effect of Injection Timing and Compression Ratio on Performance, Combustion and Emission Characteristics of a Variable Compression Ratio Engine Fueled with Mango Seed Methyl Ester

Effect of Injection Timing and Compression Ratio on Performance, Combustion and Emission Characteristics of a Variable Compression Ratio Engine Fueled with Mango Seed Methyl Ester

Research and development of new variable compression ratio (VCR) engine mechanism (1st report, Basic characteristics and design of VCR engine mechanism)

Research and development of new variable compression ratio (VCR) engine mechanism (1st report, Basic characteristics and design of VCR engine mechanism)

Experimentally Optimization of a Variable Compression Ratio Engine Performance Using Different Blends of Cotton Seed with Diesel Fuel at Different Compression Ratio

Experimentally Optimization of a Variable Compression Ratio Engine Performance Using Different Blends of Cotton Seed with Diesel Fuel at Different Compression Ratio

Study of Variable Compression Ratio Engine (VCR) and Different Innovations to Achieve VCR

Study of Variable Compression Ratio Engine (VCR) and Different Innovations to Achieve VCR

Investigation on the performance of a variable compression ratio engine operated with raw cardanol kerosene blends

ABSTRACTIn this study raw cardanol, which is a renewable biofuel, was blended with kerosene and used as a test fuel in a four-stroke variable compression ratio 3.5-kW diesel engine. Volume basis test blends of cardanol and kerosene, such as BK20 (20% kerosene and 80% cardanol), BK30 (30% kerosene and 70% cardanol) and BK40 (40% kerosene and 60% cardanol), were prepared and tested for three different compression ratios (16:1, 17:1 and 18:1) at various load conditions and compared with diesel fuel. It was observed that when the compression ratio increased from 16:1 to 18:1, the brake thermal efficiency increased from 23.87 to 27.30% for BK20, 26.83 to 29.87% for BK30, and 24.28 to 28.62% for BK40, with reduction in carbon monoxide, unburned hydrocarbon and smoke emission. But NOx emission was increased by 18.7, 1.8 and 7.3%, respectively, for BK20, BK30 and BK40 blends at the highest compression ratio relative to diesel. This study demonstrates that cardanol–kerosene blends can be used as diesel engine fuel at higher compression ratios.

Influences of dual bio-fuel (Jatropha biodiesel and turpentine oil) on single cylinder variable compression ratio diesel engine

The paper experimentally investigates the performance and exhaust emissions of a variable compression ratio engine fueled with 100%, 90%, 70% and 50% Jatropha bio-diesel and turpentine oil. In this paper, highly viscous Jatropha biodiesel is blended with relatively low viscosity turpentine oil in various proportions resulting in effective viscosity comparable with that of standard diesel with a view to developing a new alternative fuel which is comparable equally cost effective and eliminates dependency on conventional diesel fuel. Experimental analysis is carried out on ATE Make VCRE_MF single cylinder, naturally aspired, four stroke, and variable compression ratio diesel engine to study combustion performance and emission properties via conventional diesel fuel and different blends of Jatropha biodiesel with turpentine oil. Dual biofuel blend is found to be the greatest substitute to fossil (diesel) fuel in all aspects such as emissions and performance. Experiments have been accompanied at CR (compression ratio) of 15.5:1, 17:1, 18.5:1 and 20:1. Further, dual biofuel blend (JBT 50) resulted at full load and compression ratio 20, there was 2.17% increase in brake thermal efficiency and 13.04%, 17.5%, 4.21% and 30.8% decrease in CO, HC and NOx and smoke opacity respectively while CO2 was observed to increase by 11.04% respectively.