The primary claimed benefit of the revolving cylinder, axial piston engine is that a four-cycle, reciprocating piston engine can be achieved without the need for a complex and expensive valve train. The intake and exhaust flows are controlled by simple ports in the cylinder heads. Costs are further reduced because all cylinders at each end of the engine share a common fuel injector and/or spark plug. Additionally, the designs are typically compact and lightweight.
Most revolving cylinder, axial piston engine designs utilize a fixed, multi-lobed barrel-type cam and rollers on the pistons to control the reciprocating movement of the pistons. [1] The benefit of this approach, versus a conventional crankshaft-and-connecting-rod mechanism, is that the kinematics of the piston motion can be optimized with regards to combustion cycle efficiency.
The primary drawback to the revolving cylinder, axial piston engine design is that rotating piston assemblies are subjected to centrifugal forces, which can result in significant friction losses. These centrifugal forces increase at the square of the angular velocity. So unless the engine is run at very low rotational speeds, the friction losses due to centrifugal forces acting on the piston assemblies can quickly become unacceptable.
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To date, commercial or military acceptance of this design is limited to torpedo propulsion systems in current use (2009) by the United States Navy's mk 46 series and mk 48 series engines which use a derivative of the original Gould swashplate engine which was developed in the early 1960s for torpedo propulsion.
Problems associated with the design of the axial piston engine include high oil consumption, high fuel consumption, low rpm limit imposed by previously discussed frictional loads, low overall horsepower, mechanical complexity and complex machining methods needs to allow the engine to stand up to the loads imposed on the components. Additional problems are noted in that, the design does not have a long lifespan when compared to other engine designs due to large numbers of moving parts and relative high stresses. Wear and tear occurs at a faster rate because the engine makes more power pulses per turn of the cam than traditional engines. Lastly, due to very high initial torque and a need for large amounts of coolant, loss of oil or coolant to this design during running will almost certainly result in a catastrophic explosion of the engine because the engine generally has very light casings or shields located in the area around the cams and connecting rods.
The benefits of the design include relatively very high initial torque when compared to other engines, very compact design, able to be made to run on a variety of fuels from gasoline, diesel, kerosene, alcohol, to more exotic/energetic mixtures such as Otto Fuel, hydrogen peroxide/fuel mixes. [2]
A pump is a device that moves fluids, or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy.
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder.
A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common features of all types. The main types are: the internal combustion engine, used extensively in motor vehicles; the steam engine, the mainstay of the Industrial Revolution; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either a spark-ignition (SI) engine, where the spark plug initiates the combustion; or a compression-ignition (CI) engine, where the air within the cylinder is compressed, thus heating it, so that the heated air ignites fuel that is injected then or earlier.
A camshaft is a shaft that contains a row of pointed cams in order to convert rotational motion to reciprocating motion. Camshafts are used in piston engines, mechanically controlled ignition systems and early electric motor speed controllers.
An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many small UAVs have used electric motors.
A four-strokeengine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed:
A pump-jet, hydrojet, or water jet is a marine system that produces a jet of water for propulsion. The mechanical arrangement may be a ducted propeller, a centrifugal pump, or a mixed flow pump which is a combination of both centrifugal and axial designs. The design also incorporates an intake to provide water to the pump and a nozzle to direct the flow of water out of the pump.
Variable displacement is an automobile engine technology that allows the engine displacement to change, usually by deactivating cylinders, for improved fuel economy. The technology is primarily used in large, multi-cylinder engines. Many automobile manufacturers have adopted this technology as of 2005, although the concept has existed for some time prior to this.
A flathead engine, also known as a sidevalve engine or valve-in-block engine, is an internal combustion engine with its poppet valves contained within the engine block, instead of in the cylinder head, as in an overhead valve engine.
The Bourke engine was an attempt by Russell Bourke, in the 1920s, to improve the two-stroke internal combustion engine. Despite finishing his design and building several working engines, the onset of World War II, lack of test results, and the poor health of his wife compounded to prevent his engine from ever coming successfully to market. The main claimed virtues of the design are that it has only two moving parts, is lightweight, has two power pulses per revolution, and does not need oil mixed into the fuel.
An axial engine is a type of reciprocating engine with pistons arranged around an output shaft with their axes parallel to the shaft. Barrel refers to the cylindrical shape of the cylinder group whilst the Z-crank alludes to the shape of the crankshaft.
A jet engine performs by converting fuel into thrust. How well it performs is an indication of what proportion of its fuel goes to waste. It transfers heat from burning fuel to air passing through the engine. In doing so it produces thrust work when propelling a vehicle but a lot of the fuel is wasted and only appears as heat. Propulsion engineers aim to minimize the degradation of fuel energy into unusable thermal energy. Increased emphasis on performance improvements for commercial airliners came in the 1970s from the rising cost of fuel.
The BMW GT 101 was a turboshaft-type gas turbine engine developed from the BMW 003 aviation engine, that was considered for installation in Nazi Germany's Panther tank. The German Army's development division, the Heereswaffenamt, studied a number of gas turbine engines for use in tanks starting in mid-1944. Although none of these was fitted operationally, the GT 101 reached a production quality stage of development. Several designs were produced over the lifetime of the program, including the GT 102 and GT 103.
A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation). The hydraulic motor is the rotary counterpart of the hydraulic cylinder as a linear actuator. Most broadly, the category of devices called hydraulic motors has sometimes included those that run on hydropower but in today's terminology the name usually refers more specifically to motors that use hydraulic fluid as part of closed hydraulic circuits in modern hydraulic machinery.
Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-
The term six-stroke engine has been applied to a number of alternative internal combustion engine designs that attempt to improve on traditional two-stroke and four-stroke engines. Claimed advantages may include increased fuel efficiency, reduced mechanical complexity, and/or reduced emissions. These engines can be divided into two groups based on the number of pistons that contribute to the six strokes.
MAHLE Powertrain Ltd is the engineering services division of MAHLE GmbH. With its headquarters in Northampton, UK and sister company in Plymouth, Michigan, United States, the company specialises in the design, development and testing of electrified powertrain systems and provides a broad spectrum of engineering services to its global customer base. MAHLE Powertrain's engineers and technical specialists are also present in the MAHLE research and development centres in Munich, Germany and Shanghai, China.
The Michel engine was an unusual form of opposed-piston engine. It was unique in that its cylinders, instead of being open-ended cylinders containing two pistons, were instead joined in a Y-shape and had three pistons working within them.
A cam engine is a reciprocating engine where, instead of the conventional crankshaft, the pistons deliver their force to a cam that is then caused to rotate. The output work of the engine is driven by this cam.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.