12 Heat Transfer in Internal Combustion Engines. M Turhulence definilions. Introduclion. In-cylinder turbulence. Engine. The operating cycle of a conventional spark ignition engine is illustrated in Figure . The essential features of internal combustion engine operation can be seen. These are called Reciprocating Internal Combustion Engines. Otto cycle. . Petrol engine can be two stroke, or four stroke type as well. Two stroke type engines.
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Fuel combustion &Fuel injection: Structure & composition of IC engine fuel, Fuel Lecture What is IC engines and components of IC engine, IC engine. Internal combustion engine fundamentals. (McGraw-Hill series in mechanical engineering). Bibliography: p. Includes index. I. Internal combustion engines. Wartsila-Sulzer RTAC is largest IC engine, but Space Shuttle Solid .. IC engines mmoonneeyy.info pdf.
So heat is transferred from the gas to the cylinder head by two different paths: Therefore, one-dimensionality is safely assumed for the unsteady component of the surface heat flux calculation. There is some controversy as to who built the first motorcycle Otto or Daimler. Further chemicals released are benzene and 1,3-butadiene that are also hazardous air pollutants. In reciprocating engines this is accomplished by turning the crankshaft Wankel Rotor Shaft which induces the cycles of intake, compression, combustion, and exhaust.
Osama M Elmardi. Engine design and car design were integral activities, almost all of the engine designers mentioned in the article also designed cars, and a few went on to become major manufacturers of automobiles. All of these inventors and more made notable improvements in the evolution of the internal combustion vehicles. The different types of fuel commonly used for car combustion engines are gasoline or petrol , diesel, and kerosene.
Many people claimed the invention of the internal combustion engine in the 's, but only one has the patent on the four stroke operating sequence.
In , Nikolaus August Otto, a German engineer, developed the four-stroke "Otto" cycle, which is widely used in transportation even today. Otto developed the four-stroke internal combustion engine when he was 34 years old. The Diesel engine is designed heavier and more powerful than gasoline engines and utilizes oil as fuel. Diesel engines are a commonly used in heavy machinery, locomotives, ships, and some automobiles.
It is important to mention that the basic operating principles of these engines have been around for more than a hundred years and they are still in place. Fascicole 3 hood and cannot recognize a thing on their automobile. Rest assured that underneath all of those wires and sensors lies an engine with the same basic operating principles of that "Otto" engine over a century old. Rivaz designed a car for his engine - the first internal combustion powered automobile.
However, his was a very unsuccessful design. In , Lenoir attached an improved engine using petroleum and a primitive carburetor to a three-wheeled wagon that managed to complete an historic fifty- mile road trip. Several years later, Marcus designed a vehicle that briefly ran at 10 mph that a few historians have considered as the forerunner of the modern automobile by being the world's first gasoline-powered vehicle. However, it was considered the first safe and practical oil engine.
Fascicole 3 - The first successful two-stroke engine was invented by Sir Dougald Clerk. It is not certain if he did indeed build a car, however, Delamare- Debouteville's designs were very advanced for the time - ahead of both Daimler and Benz in some ways at least on paper. Daimler first built a two-wheeled vehicle the "Reitwagen" Riding Carriage with this engine and a year later built the world's first four-wheeled motor vehicle. Engine design and car design were integral activities, almost all of the engine designers mentioned above also designed cars, and a few went on to become major manufacturers of automobiles.
Otto built the first practical four-stroke internal combustion engine called the "Otto Cycle Engine," and as soon as he had completed his engine, he built it into a motorcycle. Otto's contributions were very historically significant, it was his four-stoke engine that was universally adopted for all liquid-fueled automobiles going forward.
Reciprocating piston engines are by far the most common power source for land and water vehicles , including automobiles , motorcycles , ships and to a lesser extent, locomotives some are electrical but most use Diesel engines  .
Rotary engines of the Wankel design are used in some automobiles, aircraft and motorcycles. Where high power-to-weight ratios are required, internal combustion engines appear in the form of combustion turbines or Wankel engines.
Powered aircraft typically uses an ICE which may be a reciprocating engine. Airplanes can instead use jet engines and helicopters can instead employ turboshafts ; both of which are types of turbines. In addition to providing propulsion, airliners may employ a separate ICE as an auxiliary power unit. Wankel engines are fitted to many unmanned aerial vehicles.
ICEs drive some of the large electric generators that power electrical grids. The high temperature exhaust is used to boil and superheat water to run a steam turbine.
Thus, the efficiency is higher because more energy is extracted from the fuel than what could be extracted by the combustion turbine alone.
In a smaller scale Diesel generators are used for backup power and for providing electrical power to areas not connected to an electric grid. The base of a reciprocating internal combustion engine is the engine block , which is typically made of cast iron or aluminium. The engine block contains the cylinders. In engines with more than one cylinder they are usually arranged either in 1 row straight engine or 2 rows boxer engine or V engine ; 3 rows are occasionally used W engine in contemporary engines, and other engine configurations are possible and have been used.
Single cylinder engines are common for motorcycles and in small engines of machinery.
Water-cooled engines contain passages in the engine block where cooling fluid circulates the water jacket. Some small engines are air-cooled, and instead of having a water jacket the cylinder block has fins protruding away from it to cool by directly transferring heat to the air.
The cylinder walls are usually finished by honing to obtain a cross hatch , which is better able to retain the oil. A too rough surface would quickly harm the engine by excessive wear on the piston. The pistons are short cylindrical parts which seal one end of the cylinder from the high pressure of the compressed air and combustion products and slide continuously within it while the engine is in operation.
The top wall of the piston is termed its crown and is typically flat or concave. Some two-stroke engines use pistons with a deflector head. Pistons are open at the bottom and hollow except for an integral reinforcement structure the piston web. When an engine is working the gas pressure in the combustion chamber exerts a force on the piston crown which is transferred through its web to a gudgeon pin.
Each piston has rings fitted around its circumference that mostly prevent the gases from leaking into the crankcase or the oil into the combustion chamber.
A ventilation system drives the small amount of gas that escape past the pistons during normal operation the blow-by gases out of the crankcase so that it does not accumulate contaminating the oil and creating corrosion.
In two-stroke gasoline engines the crankcase is part of the air—fuel path and due to the continuous flow of it they do not need a separate crankcase ventilation system. The cylinder head is attached to the engine block by numerous bolts or studs.
It has several functions. The cylinder head seals the cylinders on the side opposite to the pistons; it contains short ducts the ports for intake and exhaust and the associated intake valves that open to let the cylinder be filled with fresh air and exhaust valves that open to allow the combustion gases to escape.
However, 2-stroke crankcase scavenged engines connect the gas ports directly to the cylinder wall without poppet valves; the piston controls their opening and occlusion instead.
The cylinder head also holds the spark plug in the case of spark ignition engines and the injector for engines that use direct injection. All CI engines use fuel injection, usually direct injection but some engines instead use indirect injection.
SI engines can use a carburetor or fuel injection as port injection or direct injection. Most SI engines have a single spark plug per cylinder but some have 2. A head gasket prevents the gas from leaking between the cylinder head and the engine block.
The opening and closing of the valves is controlled by one or several camshafts and springs—or in some engines—a desmodromic mechanism that uses no springs. The camshaft may press directly the stem of the valve or may act upon a rocker arm , again, either directly or through a pushrod. The crankcase is sealed at the bottom with a sump that collects the falling oil during normal operation to be cycled again. The cavity created between the cylinder block and the sump houses a crankshaft that converts the reciprocating motion of the pistons to rotational motion.
The crankshaft is held in place relative to the engine block by main bearings , which allow it to rotate. Bulkheads in the crankcase form a half of every main bearing; the other half is a detachable cap. In some cases a single main bearing deck is used rather than several smaller caps. A connecting rod is connected to offset sections of the crankshaft the crankpins in one end and to the piston in the other end through the gudgeon pin and thus transfers the force and translates the reciprocating motion of the pistons to the circular motion of the crankshaft.
The end of the connecting rod attached to the gudgeon pin is called its small end, and the other end, where it is connected to the crankshaft, the big end. The big end has a detachable half to allow assembly around the crankshaft. It is kept together to the connecting rod by removable bolts.
The cylinder head has an intake manifold and an exhaust manifold attached to the corresponding ports. The intake manifold connects to the air filter directly, or to a carburetor when one is present, which is then connected to the air filter.
It distributes the air incoming from these devices to the individual cylinders. The exhaust manifold is the first component in the exhaust system. It collects the exhaust gases from the cylinders and drives it to the following component in the path.
The exhaust system of an ICE may also include a catalytic converter and muffler. The final section in the path of the exhaust gases is the tailpipe. The top dead center TDC of a piston is the position where it is nearest to the valves; bottom dead center BDC is the opposite position where it is furthest from them. While an engine is in operation, the crankshaft rotates continuously at a nearly constant speed.
In a 4-stroke ICE, each piston experiences 2 strokes per crankshaft revolution in the following order. Starting the description at TDC, these are: The defining characteristic of this kind of engine is that each piston completes a cycle every crankshaft revolution. The 4 processes of intake, compression, power and exhaust take place in only 2 strokes so that it is not possible to dedicate a stroke exclusively for each of them.
Starting at TDC the cycle consist of:. While a 4-stroke engine uses the piston as a positive displacement pump to accomplish scavenging taking 2 of the 4 strokes, a 2-stroke engine uses the last part of the power stroke and the first part of the compression stroke for combined intake and exhaust.
The work required to displace the charge and exhaust gases comes from either the crankcase or a separate blower. For scavenging, expulsion of burned gas and entry of fresh mix, two main approaches are described: Loop scavenging, and Uniflow scavenging, SAE news published in the s that 'Loop Scavenging' is better under any circumstance than Uniflow Scavenging. Some SI engines are crankcase scavenged and do not use poppet valves.
Instead the crankcase and the part of the cylinder below the piston is used as a pump. The intake port is connected to the crankcase through a reed valve or a rotary disk valve driven by the engine. For each cylinder a transfer port connects in one end to the crankcase and in the other end to the cylinder wall. The exhaust port is connected directly to the cylinder wall.
The transfer and exhaust port are opened and closed by the piston. The reed valve opens when the crankcase pressure is slightly below intake pressure, to let it be filled with a new charge; this happens when the piston is moving upwards. When the piston is moving downwards the pressure in the crankcase increases and the reed valve closes promptly, then the charge in the crankcase is compressed. When the piston is moving upwards, it uncovers the exhaust port and the transfer port and the higher pressure of the charge in the crankcase makes it enter the cylinder through the transfer port, blowing the exhaust gases.
Lubrication is accomplished by adding 2-stroke oil to the fuel in small ratios. Petroil refers to the mix of gasoline with the aforesaid oil. This kind of 2-stroke engines has a lower efficiency than comparable 4-strokes engines and release a more polluting exhaust gases for the following conditions:.
The main advantage of 2-stroke engines of this type is mechanical simplicity and a higher power-to-weight ratio than their 4-stroke counterparts.
Despite having twice as many power strokes per cycle, less than twice the power of a comparable 4-stroke engine is attainable in practice. In the US, 2-stroke engines were banned for road vehicles due to the pollution. Off-road only motorcycles are still often 2-stroke but are rarely road legal. However, many thousands of 2-stroke lawn maintenance engines are in use. Using a separate blower avoids many of the shortcomings of crankcase scavenging, at the expense of increased complexity which means a higher cost and an increase in maintenance requirement.
An engine of this type uses ports or valves for intake and valves for exhaust, except opposed piston engines , which may also use ports for exhaust.
The blower is usually of the Roots-type but other types have been used too. This design is commonplace in CI engines, and has been occasionally used in SI engines. CI engines that use a blower typically use uniflow scavenging. In this design the cylinder wall contains several intake ports placed uniformly spaced along the circumference just above the position that the piston crown reaches when at BDC. An exhaust valve or several like that of 4-stroke engines is used.
The final part of the intake manifold is an air sleeve which feeds the intake ports. The intake ports are placed at an horizontal angle to the cylinder wall I. The largest reciprocating IC are low speed CI engines of this type; they are used for marine propulsion see marine diesel engine or electric power generation and achieve the highest thermal efficiencies among internal combustion engines of any kind.
Some Diesel-electric locomotive engines operate on the 2-stroke cycle. The most powerful of them have a brake power of around 4. See the external links for a in-cylinder combustion video in a 2-stroke, optically accessible motorcycle engine. Dugald Clerk developed the first two cycle engine in It used a separate cylinder which functioned as a pump in order to transfer the fuel mixture to the cylinder. In John Day simplified Clerk's design into the type of 2 cycle engine that is very widely used today.
The crankcase and the part of the cylinder below the exhaust port is used as a pump. The carburetor then feeds the fuel mixture into the crankcase through a reed valve or a rotary disk valve driven by the engine. There are cast in ducts from the crankcase to the port in the cylinder to provide for intake and another from the exhaust port to the exhaust pipe. The height of the port in relationship to the length of the cylinder is called the "port timing".
On the first upstroke of the engine there would be no fuel inducted into the cylinder as the crankcase was empty. On the downstroke, the piston now compresses the fuel mix, which has lubricated the piston in the cylinder and the bearings due to the fuel mix having oil added to it. As the piston moves downward is first uncovers the exhaust, but on the first stroke there is no burnt fuel to exhaust.
As the piston moves downward further, it uncovers the intake port which has a duct that runs to the crankcase. Since the fuel mix in the crankcase is under pressure, the mix moves through the duct and into the cylinder.
Because there is no obstruction in the cylinder of the fuel to move directly out of the exhaust port prior to the piston rising far enough to close the port, early engines used a high domed piston to slow down the flow of fuel. Later the fuel was "resonated" back into the cylinder using an expansion chamber design.
When the piston rose close to TDC, a spark ignites the fuel. As the piston is driven downward with power, it first uncovers the exhaust port where the burned fuel is expelled under high pressure and then the intake port where the process has been completed and will keep repeating.
Later engines used a type of porting devised by the Deutz company to improve performance. It was called the Schnurle Reverse Flow system. DKW licensed this design for all their motorcycles. Internal combustion engines require ignition of the mixture, either by spark ignition SI or compression ignition CI. Before the invention of reliable electrical methods, hot tube and flame methods were used. Experimental engines with laser ignition have been built.
The spark ignition engine was a refinement of the early engines which used Hot Tube ignition. When Bosch developed the magneto it became the primary system for producing electricity to energize a spark plug.
Small engines are started by hand cranking using a recoil starter or hand crank. Prior to Charles F. Kettering of Delco's development of the automotive starter all gasoline engined automobiles used a hand crank. Larger engines typically power their starting motors and ignition systems using the electrical energy stored in a lead—acid battery. The battery's charged state is maintained by an automotive alternator or previously a generator which uses engine power to create electrical energy storage.
The battery supplies electrical power for starting when the engine has a starting motor system, and supplies electrical power when the engine is off. The battery also supplies electrical power during rare run conditions where the alternator cannot maintain more than As alternator voltage falls below During virtually all running conditions, including normal idle conditions, the alternator supplies primary electrical power.
Some systems disable alternator field rotor power during wide open throttle conditions. Disabling the field reduces alternator pulley mechanical loading to nearly zero, maximizing crankshaft power.
In this case, the battery supplies all primary electrical power. Gasoline engines take in a mixture of air and gasoline and compress it by the movement of the piston from bottom dead center to top dead center when the fuel is at maximum compression. The reduction in the size of the swept area of the cylinder and taking into account the volume of the combustion chamber is described by a ratio.
Early engines had compression ratios of 6 to 1. As compression ratios were increased, the efficiency of the engine increased as well. With early induction and ignition systems the compression ratios had to be kept low. With advances in fuel technology and combustion management, high performance engines can run reliably at With low octane fuel, a problem would occur as the compression ratio increased as the fuel was igniting due to the rise in temperature that resulted.
Charles Kettering developed a lead additive which allowed higher compression ratios, which was progressively abandoned for automotive use from the s onward, partly due to lead poisoning concerns.
The fuel mixture is ignited at difference progressions of the piston in the cylinder. At low rpm, the spark is timed to occur close to the piston achieving top dead center. In order to produce more power, as rpm rises the spark is advanced sooner during piston movement. The spark occurs while the fuel is still being compressed progressively more as rpm rises. The necessary high voltage, typically 10, volts, is supplied by an induction coil or transformer.
The induction coil is a fly-back system, using interruption of electrical primary system current through some type of synchronized interrupter. The interrupter can be either contact points or a power transistor. The problem with this type of ignition is that as RPM increases the availability of electrical energy decreases. This is especially a problem, since the amount of energy needed to ignite a more dense fuel mixture is higher.
The result was often a high RPM misfire. Capacitor discharge ignition was developed. It produces a rising voltage that is sent to the spark plug. CD system voltages can reach 60, volts. The step-up transformer uses energy stored in a capacitance to generate electric spark.
With either system, a mechanical or electrical control system provides a carefully timed high-voltage to the proper cylinder. This spark, via the spark plug, ignites the air-fuel mixture in the engine's cylinders. While gasoline internal combustion engines are much easier to start in cold weather than diesel engines, they can still have cold weather starting problems under extreme conditions. For years, the solution was to park the car in heated areas.
In some parts of the world, the oil was actually drained and heated over night and returned to the engine for cold starts. In the early s, the gasoline Gasifier unit was developed, where, on cold weather starts, raw gasoline was diverted to the unit where part of the fuel was burned causing the other part to become a hot vapor sent directly to the intake valve manifold.
This unit was quite popular until electric engine block heaters became standard on gasoline engines sold in cold climates. The compression level that occurs is usually twice or more than a gasoline engine. Diesel engines take in air only, and shortly before peak compression, spray a small quantity of diesel fuel into the cylinder via a fuel injector that allows the fuel to instantly ignite.
HCCI type engines take in both air and fuel, but continue to rely on an unaided auto-combustion process, due to higher pressures and heat. This is also why diesel and HCCI engines are more susceptible to cold-starting issues, although they run just as well in cold weather once started.
Light duty diesel engines with indirect injection in automobiles and light trucks employ glowplugs or other pre-heating: Most diesels also have a battery and charging system; nevertheless, this system is secondary and is added by manufacturers as a luxury for the ease of starting, turning fuel on and off which can also be done via a switch or mechanical apparatus , and for running auxiliary electrical components and accessories. Most new engines rely on electrical and electronic engine control units ECU that also adjust the combustion process to increase efficiency and reduce emissions.
Surfaces in contact and relative motion to other surfaces require lubrication to reduce wear, noise and increase efficiency by reducing the power wasting in overcoming friction , or to make the mechanism work at all. Also, the lubricant used can reduce excess heat and provide additional cooling to components.
At the very least, an engine requires lubrication in the following parts:. In 2-stroke crankcase scavenged engines, the interior of the crankcase, and therefore the crankshaft, connecting rod and bottom of the pistons are sprayed by the 2-stroke oil in the air-fuel-oil mixture which is then burned along with the fuel. The valve train may be contained in a compartment flooded with lubricant so that no oil pump is required. In a splash lubrication system no oil pump is used.
Instead the crankshaft dips into the oil in the sump and due to its high speed, it splashes the crankshaft, connecting rods and bottom of the pistons.
The connecting rod big end caps may have an attached scoop to enhance this effect. The valve train may also be sealed in a flooded compartment, or open to the crankshaft in a way that it receives splashed oil and allows it to drain back to the sump. Splash lubrication is common for small 4-stroke engines.
In a forced also called pressurized lubrication system , lubrication is accomplished in a closed loop which carries motor oil to the surfaces serviced by the system and then returns the oil to a reservoir. The auxiliary equipment of an engine is typically not serviced by this loop; for instance, an alternator may use ball bearings sealed with their own lubricant.
The reservoir for the oil is usually the sump, and when this is the case, it is called a wet sump system. When there is a different oil reservoir the crankcase still catches it, but it is continuously drained by a dedicated pump; this is called a dry sump system.
On its bottom, the sump contains an oil intake covered by a mesh filter which is connected to an oil pump then to an oil filter outside the crankcase, from there it is diverted to the crankshaft main bearings and valve train. The crankcase contains at least one oil gallery a conduit inside a crankcase wall to which oil is introduced from the oil filter. The main bearings contain a groove through all or half its circumference; the oil enters to these grooves from channels connected to the oil gallery.
The crankshaft has drillings which take oil from these grooves and deliver it to the big end bearings. All big end bearings are lubricated this way. A single main bearing may provide oil for 0, 1 or 2 big end bearings. A similar system may be used to lubricate the piston, its gudgeon pin and the small end of its connecting rod; in this system, the connecting rod big end has a groove around the crankshaft and a drilling connected to the groove which distributes oil from there to the bottom of the piston and from then to the cylinder.
Other systems are also used to lubricate the cylinder and piston. The connecting rod may have a nozzle to throw an oil jet to the cylinder and bottom of the piston. That nozzle is in movement relative to the cylinder it lubricates, but always pointed towards it or the corresponding piston. Typically a forced lubrication systems have a lubricant flow higher than what is required to lubricate satisfactorily, in order to assist with cooling.
Specifically, the lubricant system helps to move heat from the hot engine parts to the cooling liquid in water-cooled engines or fins in air-cooled engines which then transfer it to the environment. The lubricant must be designed to be chemically stable and maintain suitable viscosities within the temperature range it encounters in the engine.
Common cylinder configurations include the straight or inline configuration , the more compact V configuration , and the wider but smoother flat or boxer configuration. Aircraft engines can also adopt a radial configuration , which allows more effective cooling.
More unusual configurations such as the H , U , X , and W have also been used. Multiple cylinder engines have their valve train and crankshaft configured so that pistons are at different parts of their cycle.
It is desirable to have the piston's cycles uniformly spaced this is called even firing especially in forced induction engines; this reduces torque pulsations  and makes inline engines with more than 3 cylinders statically balanced in its primary forces.
However, some engine configurations require odd firing to achieve better balance than what is possible with even firing. With an even firing pattern, the pistons would move in unison and the associated forces would add.
Multiple crankshaft configurations do not necessarily need a cylinder head at all because they can instead have a piston at each end of the cylinder called an opposed piston design. Because fuel inlets and outlets are positioned at opposed ends of the cylinder, one can achieve uniflow scavenging, which, as in the four-stroke engine is efficient over a wide range of engine speeds.
Thermal efficiency is improved because of a lack of cylinder heads. This design was used in the Junkers Jumo diesel aircraft engine, using two crankshafts at either end of a single bank of cylinders, and most remarkably in the Napier Deltic diesel engines.
These used three crankshafts to serve three banks of double-ended cylinders arranged in an equilateral triangle with the crankshafts at the corners. It was also used in single-bank locomotive engines , and is still used in marine propulsion engines and marine auxiliary generators.
Most truck and automotive diesel engines use a cycle reminiscent of a four-stroke cycle, but with compression heating causing ignition, rather than needing a separate ignition system.
This variation is called the diesel cycle. In the diesel cycle, diesel fuel is injected directly into the cylinder so that combustion occurs at constant pressure, as the piston moves. Otto cycle is the typical cycle for most of the cars internal combustion engines, that work using gasoline as a fuel. Otto cycle is exactly the same one that was described for the four-stroke engine.
It consists of the same major steps: Intake, compression, ignition, expansion and exhaust. In , Nikolaus Otto manufactured and sold a double expansion engine the double and triple expansion principles had ample usage in steam engines , with two small cylinders at both sides of a low-pressure larger cylinder, where a second expansion of exhaust stroke gas took place; the owner returned it, alleging poor performance.
In , the concept was incorporated in a car built by EHV Eisenhuth Horseless Vehicle Company ;  and in the 21st century Ilmor designed and successfully tested a 5-stroke double expansion internal combustion engine, with high power output and low SFC Specific Fuel Consumption. The six-stroke engine was invented in Four kinds of six-stroke use a regular piston in a regular cylinder Griffin six-stroke, Bajulaz six-stroke, Velozeta six-stroke and Crower six-stroke , firing every three crankshaft revolutions.
These systems capture the wasted heat of the four-stroke Otto cycle with an injection of air or water. The Beare Head and "piston charger" engines operate as opposed-piston engines , two pistons in a single cylinder, firing every two revolutions rather more like a regular four-stroke.
The very first internal combustion engines did not compress the mixture. The first part of the piston downstroke drew in a fuel-air mixture, then the inlet valve closed and, in the remainder of the down-stroke, the fuel-air mixture fired. The exhaust valve opened for the piston upstroke. These attempts at imitating the principle of a steam engine were very inefficient.
There are a number of variations of these cycles, most notably the Atkinson and Miller cycles. The diesel cycle is somewhat different. Split-cycle engines separate the four strokes of intake, compression, combustion and exhaust into two separate but paired cylinders.
The first cylinder is used for intake and compression. The compressed air is then transferred through a crossover passage from the compression cylinder into the second cylinder, where combustion and exhaust occur.
A split-cycle engine is really an air compressor on one side with a combustion chamber on the other. Previous split-cycle engines have had two major problems—poor breathing volumetric efficiency and low thermal efficiency. However, new designs are being introduced that seek to address these problems. The Scuderi Engine addresses the breathing problem by reducing the clearance between the piston and the cylinder head through various turbo charging techniques.
The Scuderi design requires the use of outwardly opening valves that enable the piston to move very close to the cylinder head without the interference of the valves. Scuderi addresses the low thermal efficiency via firing after top dead centre ATDC.
Firing ATDC can be accomplished by using high-pressure air in the transfer passage to create sonic flow and high turbulence in the power cylinder. Jet engines use a number of rows of fan blades to compress air which then enters a combustor where it is mixed with fuel typically JP fuel and then ignited. The burning of the fuel raises the temperature of the air which is then exhausted out of the engine creating thrust.
A gas turbine compresses air and uses it to turn a turbine.
It is essentially a jet engine which directs its output to a shaft. There are three stages to a turbine: A gas turbine is a rotary machine similar in principle to a steam turbine and it consists of three main components: