Compressed Air Engines Research Articles

Design and development of compressed air engine

This research aims to build an engine that uses compressed air as a fuel to provide mechanical energy to rotate a crankshaft which can be used for useful work. The specific objectives of the study are to design and fabricate a compressed air engine within a pressure range of two to five bar and to test the engine's performance in terms of angular velocity of the crankshaft, torque produced at the crankshaft, stress and displacement analysis on the base frame and efficiency of the engine. To achieve these objectives, design equations of inertial forces in reciprocating parts is used to calculate the torque produced at the crankshaft, computational tool is used to calculate the stress and displacement analysis on the base of the frame and experimentally the engine is tested to calculate the angular velocity at the crankshaft and valve timing so that crankshaft produces uniform rotational motion. It was found that, the angular velocity is directly and Arduino valve timing is inversely proportional to the pressure exerted by the piston. A force of 245.43 N is exerted by the pneumatic piston cylinder when rotated at 100 RPM producing a torque of 45 Nm at efficiency of 29.60%. The base frame exerted a maximum stress of 48 Mpa and maximum displacement of 1.9 mm, both at the location at which the crankshaft is installed. It is important to note that the results may not be generalizable to all compressed air engines and further research is needed to fully understand their performance and capabilities.

Experimental Research on Performance Comparison of Compressed Air Engine under Different Operation Modes

An air-powered vehicle is a low-cost method to achieve low-pollution transportation, and compressed air engines (CAE) have become a research hotspot for their compact structure, low consumption, and wide working conditions. In this study, a pneumatic motor (PM) test bench is built and tested under different inlet pressures, operation modes, and three driving cycles. On the basis of the data obtained by sensors, power output, compressed air consumption rate, and efficiency are calculated to evaluate the pneumatic motor performances. The results show that with an increase in rotation speed, the output power and efficiency first increase and then decrease, and the compression air consumption rate decreases. With an increase in torque, the rotation speed decreases, and the power output and efficiency first increase and then decrease. With an increase in mass flow rate, the torque increases, the power output and efficiency first increase and then decrease. The pneumatic motor achieves the best performance under a rotation speed of 800–1200 rpm, where power output, efficiency, and compressed air consumption rates are 1498 W, 13.6%, and 10 J/g, respectively. The pneumatic motor achieves the best power output and efficiency under the UDDS driving cycle.

Investigation of friction properties in the piston-cylinder liner region of a single-cylinder compressed air engine using the GT-SUITE program

Dependence on nonrenewable fuels continues to a great extent today. Overuse of fossil fuels has brought along various environmental problems. In order to reduce such problems, compressed air engines have developed significantly during the last 20 years. Compressed air engines are environment-friendly engines that do not use fossil fuel and achieve expansion using compressed air. It is of great importance for engine efficiency to decrease friction losses of piston engines. There are not many studies in the literature focusing on friction manner of piston ring liner parts of compressed air engines with a piston. In this article, the transformation of a four-stroke gasoline engine with 388 cm3 displacement into a compressed air engine has been carried out and the friction manner between piston cylinder liner has been modeled with the help of GT-SUITE program using in-cylinder pressure-cylinder volume (P-V) data obtained from different engine loads under operating pressure of 12 bar and geometrical size of the engine. It has been determined according to the results of the simulation that asperity friction losses have not changed significantly in top dead center and bottom dead center regions due to low testing speed, and hydrodynamic power losses have occurred in the middle of the course. Lack of combustion reactions in such engines has resulted in compression leakages and unavailability of a quality oil film layer. Since there are no combustion reactions, the eccentric movement of the pistons of the compressed air engines is changed by the lubricating oil, engine speed, compression leaks, and viscosity parameters.

Performance Evaluation of a Single Cylinder Compressed Air Engine: An Experimental Study

Abstract The quest to reduce dangerous environmental emissions has led to the research and use of alternate and renewable energy sources. One of the major contributors to the dangerous environmental emissions is the automotive industry. The world is, therefore, quickly moving towards hybrid and electric vehicles. An alternate pollution-free automotive engine is a compressed-air engine, which is powered by compressed air and is more efficient than the electric engine since it requires less charging time than a traditional battery-operated engine. Furthermore, the tanks used in compressed-air engines have a longer lifespan in comparison to the batteries used in electric vehicles. However, extensive research is required to make this engine viable for commercial use. The current study is a step forward in this direction and shows the performance analysis of a single-cylinder compressed-air engine, developed from a four-stroke, single-cylinder, 70 cc gasoline engine. The results show that compressed-air engines are economic, environmental friendly and efficient.

Performance and economic evaluation of CO2 (R744) air conditioning system driven by compressed air engine

Traditional building air conditioning uses electricity or thermal energy to drive the refrigeration cycle. The energy released by the expansion of compressed air can also be used for driving the refrigeration cycle. Moreover, the expanded low-temperature air can be used in the air conditioning system too. In this paper, three forms of CO2 air conditioning systems driven by novel reciprocating piston compressed air engines were designed, namely EAGC (Exhaust Air for Gas Cooler), EAS (Exhaust Air for Sub-cooler), and EASC (Exhaust Air for Space Cooling), to analyze the performance and economics of CO2 air conditioning systems combined with compressed air energy storage technology. Twenty-seven typical cities were selected in different climate regions in China to evaluate the systems' performance and running cost under outdoor temperature changes and different electricity prices. The results show that compared with the electricity-driven CO2 air conditioning system, the three systems can greatly improve the system COP (Coefficient of Performance) but still cannot reach the performance level of the conventional freon refrigeration systems. However, in cities like Beijing and Shanghai with the large peak-to-valley electricity price difference, EASC system compared to the electricity-driven R410A air conditioning system running costs are lower, the average running cost per hour can be saved 11.96% and 16.35%, respectively. This means that the CO2 air conditioning system with compressed air energy storage technology has a certain economic application value and can be popularized on reasonable occasions. This innovative system design can help solve the contradiction between supply and demand of building energy, realize leisure energy consumption, and reduce the economic cost of energy consumption on the demand side.

Design and experimental investigation of compressed air engine

In recent times, non-renewable fuel resources have become very narrow due to more usage. Overusing of fossil fuels has brought many environmental problems. For reducing these problems, compressed air engines have attracted much consideration over the past 15 years. The compressed air engine is getting consideration around the world due to the more benefits from renewable and has to generate no emission gases. The temperature coming out from the compressed air engine is lower than the atmospheric temperature. But still, vehicles using air as a fuel have studied a idea. The main objective of this work is to change the four-stroke internal combustion engine into a compressed air engine utilizing a solenoid valve instead of the sparkplug. In this work, the design and experimental analysis of a compressed air engine are presented. The results show a significant improvement in engine performance.

AUTOMOBILE POWERED BY COMPRESSED AIR, PNEUMATIC CAR 2020

Urgency of the research. The issue of a pneumatic car – air car developing is very important nowadays, as the environment is threatened by a variety of emissions from cars. The decision has to be made. There are various alternatives to internal combustion engines, and one of them is compressed air engines. Target setting. The main goal is to develop a car that runs on compressed air and create a frame that matches the dimensions specified for the competition. Actual scientific researches and issues analysis. In recent years, Aventics has organized competitions and races on pneumatic vehicles. These races have been running by Emerson for thirteen years. The pneumatic cars had to take part in all categories of competitions. We have been dealing with this issue in Slovakia for the third year, and this pneumatic car is our third model. Uninvestigated parts of general matters defining. This article describes a car that runs on compressed air, as well as describes in more detail the frame used and its design features. The research objective. The purpose of this study is to analyze the pneumatic vehicle, its parts and to give a detailed description of the manufactured frame and its properties. The corresponding frame was made on the basis of the conditions determined by Emerson's competitions. The statement of basic materials. The analysis was conducted on the basis of the terms of the competition. These conditions are determined by the maximum and minimum dimensions of the car. Based on these conditions, a frame was developed, it was previously analyzed by FEA - MKP. The description of the frame is given below. Conclusions. This article describes the design of a pneumatic car for competitions. The competition focus is cars powered by compressed air. The pneumatic cars were developed by bachelors and technical school. The design of this car has passed the initial inspection and has been approved by the organizers of the competition.

Modelling Methodology of Piston Pneumatic Air Engine Operation

Abstract The article presents a mathematical model describing the operation of a piston pneumatic air engine. Compressed air engines are an alternative to classic combustion solutions as they do not directly emit toxic exhaust components. In the study, a modified internal combustion piston engine was adopted as pneumatic engine. The mathematical model was divided on the two subsystems, that is, mechanical and pneumatic. The mechanical subsystem describes a transformation of compressed air supply process parameters to energy transferred to the piston and further the conversion of the translational to rotary motion; in turn, in the pneumatic part, the lumped elements method was used. Calculations were carried out using the Matlab-Simulink software, resulting in the characteristics of external and economic indicators. The presented mathematical model can be ultimately developed with additional elements, such as the intake or exhaust system, as well as timing system control.

CFD modelling and validation of the rotary lobe compressed air expander

The article covers the CFD analysis of the compressed air rotary lobe expander. Compressed air engines are commonly used in the explosion hazard zones, where the others power sources cannot be applied. The lobe construction seems to be cheaper solution in comparison with the classic turbine expanders at the corresponding power level. In the paper the rotary lobe compressed air expander model was developed in the ANSYS CFX software. During implementation of the proposed numerical model the mesh motion problem was solved, which was challenging due to relatively small gaps between lobes and the housing as well as due to high rotary speed of lobes. What is more, the compressible fluid model was applied. Therefore, these conditions make the undertaken problem more complex and calculation more time consuming. Finally, the model was validated applying the catalogue data of the producer. In the paper description of the developed model was presented. Then the results of simulations with their validation were shown which proved the correctness and accuracy of the model. The developed tool might be very useful for the further analysis of the expander including its optimization in terms of improvement of its efficiency or energy gain.

The Feasibility Study of Regenerative Braking Applications in Air Hybrid Engine

This study investigated the feasibility of using piston compressed air engines in four stroke internal combustion (IC) engines for regenerative braking application. First, thermodynamic and gas dynamic simulation models were developed to analyze the engine cylinder pressure and recycle pressure in the storage tank during operation. Commercially available software (MATLAB) was used to develop the simulation models. Second, a 100 cm3 IC engine was modified for compressed air operation to examine recycle pressure and fluid properties under various cranking torques and buffer volumes during regenerative braking. The experimental results revealed that the maximum regenerative pressure of the four stroke regenerative braking was 2.91 bar.

Comparative study on air distribution system for piston-type compressed air engine

The open and close duration, angle, and pressure of the intake and exhaust valves substantially influence compressed air engine efficiency and output power. In the actual prototype, the air distribution system can be of two types, cam air distribution type and rotary air distribution type. Compressed air engine based on the two types has been investigated. However, there have been debates over the advantages and disadvantages of these two technologies. The article aims to compare two technologies from the output power and energy efficiency. To verify theoretical analyses’ model, an experimental system is built to test the output power and efficiency of compressed air engine with cam air distribution system. It is shown that the output power of the compressed air engine with rotary air distribution system is higher than that of the compressed air engine with cam air distribution system. When the rotation speed is equal to 800 r/min, the output power of the compressed air engine with rotary air distribution system is about five times as much as that of the compressed air engine with cam air distribution system. The efficiency of two kinds of compressed air engines all declines with a rise in the rotation speed. Furthermore, the energy efficiency of the compressed air engine with rotary air distribution system is higher than that of the compressed air engine with cam air distribution system by approximately 10%. The analyses also indicate that sealing and lubrication are key to practical application of the compressed air engine with rotary air distribution system.

Working characteristics of two types of compressed air engine

To avoid environment pollution caused by internal combustion engine vehicles, compressed air engines (CAEs) have attracted much attention over the past decade. Two kinds of compressed air engines, single cylinder piston-type CAE (SCAE) and double crank link CAE (DCAE), have been investigated. However, SCAEs have low energy efficiency and output power; particularly, when rotational speed is high. To solve these shortcomings, the DCAE is proposed, which can obtain higher output power at higher rotational speeds. Using co-simulation technology, the average output power, energy efficiency, and cylinder pressure of the two kinds of CAEs were obtained. The average output power and efficiency characteristics of the SCAE were obtained by simulation and experiment; the simulation results were consistent with the experimental results, which verified that the united simulation model is accurate and effective. The results show that the pressure inside the DCAE cylinder is barely influenced by the rotational speed, and the output torque remains generally stable with an increase in the rotational speed. The average energy efficiency of both kinds of CAE declines with an increase in the rotational speed when the supply pressure is set at 2 MPa. The air power efficiency of the DCAE is about 1.86–2.86 times that of the SCAE. When the rotational speed is 800 rpm, the air power efficiency of the DCAE is 2.86 times than that of the SCAE. It is clear that the DCAE can improve the CAE performance under high rotational speeds.

Modified intake and exhaust system for piston-type compressed air engines

This study investigated a modified intake and exhaust system for piston-type compressed air engines. A conventional 100-cm3 four-stroke internal combustion engine was modified to a two-stroke compressed air engine and its output power and fluid properties at various intake pressures and rotational speeds were examined. The torque output, airflow rate, and cylinder pressure were recorded; these values reflected the fluid characteristics of the compressed air engine during operation. The conventional engine design uses a cam mechanism for controlling the intake and exhaust valves, wherein the valves open and close gradually. To overcome this drawback, a rotary intake and exhaust system was designed in which the valves open and close quickly. This new system is operable at air pressures as high as 13 bar, and the operating cylinder pressure rises faster than it does in systems featuring the conventional cam mechanism. Air engines installed with the new rotary intake and exhaust system yield an output power of 2.15 kW and a torque of 15.97 Nm at 13 bar.

Dimensionless Study on Efficiency and Speed Characteristics of a Compressed Air Engine

To eliminate the pollutants exhausting, this paper presents an idea of using compressed air as the power source for engines. Instead of an internal combustion (IC) engine, this automobile is equipped with a compressed air engines (CAEs), which transforms the energy of the compressed air into mechanical kinematic energy. Through analysis of the working process of a CAE, the mathematical model is setup. Experiments are carried out to verify the engine performance and the basic model’s validity. By selecting the appropriate reference values, the mathematical model is transformed to a dimensionless expression. The dimensionless speed and efficiency characteristics of the CAE are obtained. Through analysis, it can be obtained that the dimensionless average rotating speed is mainly determined by the intake duration angle, the dimensionless inertia parameter, the dimensionless exhaust pressure, and the scale factor of exhaust valve. Moreover, the efficiency of the CAE is mainly determined by the dimensionless exhaust pressure, the intake duration angle and the dimensionless cylinder clearance. This research can be referred to in the design of CAE and the study on optimization of the CAE.

ANALYSIS AND OPTIMIZATION of INJECTION TIMING for AN ADVANCED COMPRESSED AIR ENGINE KIT

Increasing air pollution levels and the global oil crisis has become a major hindrance in the growth of our automobile sector. Traditional Internal Combustion engines running on non-renewable fuels are proving to be the major culprit for the harmful effects on environment. With few modifications and also with assistance of few additional components current small SI engines can be modified into a pneumatic engine (commonly known as Compressed Air Engines) without much technical complications where the working fluid is compressed air. The working principle is very basic as adiabatic expansion of the compressed air takes place inside the cylinder pushing the piston downwards creating enough MEP to run the crank shaft at decent RPM. With the assistance of new research and development on pneumatic engines can explore the potential of pneumatic engines as a viable option over IC engines. The paper deals with analysis on RPM variation with corresponding compressed air injection at different crank angles from TDC keeping constant injection time period. Similarly RPM variation can also be observed at different injection pressures with similar injection angle variation. A setup employing a combination of magnetic switch (reed switch), magnets and solenoid valve is used in order to injection timing control. A conclusive data is obtained after detailed analysis of RPM variation that can be employed in newly modified pneumatic engines in order to enhance the running performance. With a number of benefits offered by pneumatic engine over IC engines such as no emissions, better efficiency, low running cost, light weight accompanied by optimized injection conditions can cause a significant development in pneumatic engines without any major alteration.

The Applications of Piston Type Compressed Air Engines on Motor Vehicles

This study presents the applications of piston type compressed air engine on a small size motor vehicle. A conventional 100cc four-stroke internal combustion engine(IC engine) was modified to a two-stroke compressed air engine and the power output has been examined with different intake valve timing and supply air pressures on a test bench. The compressed air engine was installed on a motorcycle for the demonstration of vehicle application. The success of this application demonstrates the concept of green energy vehicle with zero emission using compressed air energy. The motorcycle installed with the compressed air engine can operate at maximum speed around 38.2km/hr. and distance up to 5km.

A study of the extent and scope of local vibration hazards in Japan.

Following World War II, mechanized tools utilizing compressed air, electric motors and gasoline engines were introduced in various industries in Japan in order to achieve higher productivity and reduction of labor. Accordingly, many vibration began to present themselves. In 1947, Japanese Ministry of Labor recognized vibration as an occupational disease. However, until vibration induced by using chain saws in national forestries became a serious social problem in 1965, no preventive measures were taken.In 1975, Ministry of Labor decided to apply the guidelines for counter-measures against vibration hazards to six industries. Moreover, 1977, it allowed workers using 18 sorts of mechanized tools involving vibration exposure to seek protection under labor insurance regulations.In order to promote countermeasures against vibration hazards, Japan Association of Industrial Health organized The Committee on Vibration Haz-ards in 1977, and its activities continued for three years. This report is con-cerned with studies of which authors took partial charge among various committee projects. It has become clear that extent and scope of present local vibration in Japan, which were surveyed through case and epide-miological reports, as well as vibration and noise measurement, are extremely large.

On Compressed-Air Engines for Tramways

On Compressed-Air Engines for Tramways