internal-combustion-engine--blog

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Capacitor discharge ignition

CDI module Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. It was originally developed to overcome the long charging times associated with high inductance coils used in inductive discharge ignition (IDI) systems, making the ignition system more suitable for high engine speeds (for small engines, racing engines and rotary engines). The capacitive-discharge ignition uses capacitor discharge current to the coil to fire the spark plugs. More details Android, Windows

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Scotch yoke

Comparison of displacement and acceleration for a Scotch yoke compared with a crank and slider The Scotch yoke (also known as slotted link mechanism) is a reciprocating motion mechanism, converting the linear motion of a slider into rotational motion, or vice versa. The piston or other reciprocating part is directly coupled to a sliding yoke with a slot that engages a pin on the rotating part. The location of the piston versus time is a sine wave of constant amplitude, and constant frequency given a constant rotational speed. More details Android, Windows

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V6 engine

"V6" redirects here. For other uses, see V6 (disambiguation). A V6, 24-valve, DOHC engine A V6 engine is a V engine with six cylinders mounted on the crankshaft in two banks of three cylinders, usually set at either a 60 or 90 degree angle to each other. The V6 is one of the most compact engine configurations, usually ranging from 2.0 L to 4.3 L displacement, shorter than the inline 4 and more compact than the V8 engine. Because of its short length, the V6 fits well in the widely used transverse engine front-wheel drive layout. It is becoming more common as the space allowed for engines in modern cars is reduced at the same time as power requirements increase, and has largely replaced the inline 6, which is nearly twice as long - too long to fit in many modern engine compartments - and the V8, which is larger, more expensive, and has poorer fuel economy. The V6 engine has become widely adopted for medium-sized cars, often as an optional engine where an inline 4 is standard, or as a standard engine where a V8 is a higher-cost performance option. More details Android, Windows

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Six-stroke engine

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. In the single-piston designs, the engine captures the heat lost from the four-stroke Otto cycle or Diesel cycle and uses it to drive an additional power and exhaust stroke of the piston in the same cylinder in an attempt to improve fuel-efficiency and/or assist with engine cooling. The pistons in this type of six-stroke engine go up and down three times for each injection of fuel. These designs use either steam or air as the working fluid for the additional power stroke. The designs in which the six strokes are determined by the interactions between two pistons are more diverse. The pistons may be opposed in a single cylinder or may reside in separate cylinders. Usually one cylinder makes two strokes while the other makes four strokes giving six piston movements per cycle. The second piston may be used to replace the valve mechanism of a conventional engine, which may reduce mechanical complexity and enable an increased compression ratio by eliminating hotspots that would otherwise limit compression. The second piston may also be used to increase the expansion ratio, decoupling it from the compression ratio. Increasing the expansion ratio in this way can increase thermodynamic efficiency in a similar manner to the Miller or Atkinson cycle. More details Android, Windows

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Inline-four engine

Ford inline-four engine with cylinder head removed A cutaway Renault-Nissan M9R 2.0L Straight-4 DOHC Common rail diesel engine The inline-four engine or straight-four engine is a type of inline internal combustion four-cylinder engine with all four cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft. Where it is inclined, it is sometimes called a slant-four. In a specification chart or when an abbreviation is used, an inline-four engine is listed either as I4 or L4 (for longitudinal, to avoid confusion between the digit 1 and the letter I). The inline-four layout is in perfect primary balance and confers a degree of mechanical simplicity which makes it popular for economy cars. However, despite its simplicity, it suffers from a secondary imbalance which causes minor vibrations in smaller engines. These vibrations become more powerful as engine size and power increase, so the more powerful engines used in larger cars generally are more complex designs with more than four cylinders. Today almost all manufacturers of four-cylinder engines for automobiles produce the inline-four layout, with Subaru's flat-four engine being a notable exception, and so four-cylinder is synonymous with and a more widely used term than inline-four. The inline-four is the most common engine configuration in modern cars, while the V6 engine is the second most popular. In the late 2000s (decade), due to stringent government regulations mandating reduced vehicle emissions and increased fuel efficiency, the proportion of new vehicles sold in the U.S. with four-cylinder engines (largely of the inline-four type) rose from 30 percent to 47 percent between 2005 and 2008, particularly in mid-size vehicles where a decreasing number of buyers have chosen the V6 performance option. More details Android, Windows

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Four-stroke engine

Four-stroke cycle used in gasoline/petrol engines. 1 = Intake, 2 = Compression, 3 = Power, 4 = Exhaust. The right blue side is the intake port and the left brown side is the exhaust port. The cylinder wall is a thin sleeve surrounding the piston head which creates a space for the combustion of fuel and the genesis of mechanical energy. A four-stroke engine (also known as four cycle) is an internal combustion (IC) engine in which the piston completes four separate strokes while turning a crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed: Intake: This stroke of the piston begins at top dead center (T.D.C.) and ends at bottom dead center (B.D.C.). In this stroke the intake valve must be in the open position while the piston pulls an air-fuel mixture into the cylinder by producing vacuum pressure into the cylinder through its downward motion. Compression: This stroke begins at B.D.C, or just at the end of the suction stroke, and ends at T.D.C. In this stroke the piston compresses the air-fuel mixture in preparation for ignition during the power stroke (below). Both the intake and exhaust valves are closed during this stage. Combustion: This is the start of the second revolution of the four stroke cycle. At this point the crankshaft has completed a full 360 degree revolution. While the piston is at T.D.C. (the end of the compression stroke) the compressed air-fuel mixture is ignited by a spark plug (in a gasoline engine) or by heat generated by high compression (diesel engines), forcefully returning the piston to B.D.C. This stroke produces mechanical work from the engine to turn the crankshaft. Exhaust: During the exhaust stroke, the piston once again returns from B.D.C. to T.D.C. while the exhaust valve is open. This action expels the spent air-fuel mixture through the exhaust valve. More details Android, Windows

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Cylinder

Four-stroke cycle (or Otto cycle) 1. Intake 2. Compression 3. Power 4. Exhaust A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work. Cylinders may be sleeved (lined with a harder metal) or sleeveless (with a wear-resistant coating such as Nikasil). A sleeveless engine may also be referred to as a "parent-bore engine". A cylinder's displacement, or swept volume, can be calculated by multiplying its cross-sectional area (the square of half the bore by pi) by the distance the piston travels within the cylinder (the stroke). The engine displacement can be calculated by multiplying the swept volume of one cylinder by the number of cylinders. Presented symbolically, (Cylinder Volume) = π ⋅ ( bore 2 ) 2 ⋅ Stroke {\displaystyle {\text{(Cylinder Volume)}}=\pi \cdot \left({\frac {\text{bore}}{2}}\right)^{2}\cdot {\text{Stroke}}} (Engine Displacement) = (Cylinder Volume) ⋅ (Number of Cylinders) {\displaystyle {\text{(Engine Displacement)}}={\text{(Cylinder Volume)}}\cdot {\text{(Number of Cylinders)}}} A piston is seated inside each cylinder by several metal piston rings fitted around its outside surface in machined grooves; typically two for compressional sealing and one to seal the oil. The rings make near contact with the cylinder walls (sleeved or sleeveless), riding on a thin layer of lubricating oil; essential to keep the engine from seizing and necessitating a cylinder wall's durable surface. During the earliest stage of an engine's life, its initial breaking-in or running-in period, small irregularities in the metals are encouraged to gradually form congruent grooves by avoiding extreme operating conditions. Later in its life, after mechanical wear has increased the spacing between the piston and the cylinder (with a consequent decrease in power output) the cylinders may be machined to a slightly larger diameter to receive new sleeves (where applicable) and piston rings, a process sometimes known as reboring. More details Android, Windows

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Cetane number

Cetane number, Centane rating or CN is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It is an inverse of the similar octane rating for gasoline. The CN is an important factor in determining the quality of diesel fuel, but not the only one; other measurements of diesel's quality include (but are not limited to) energy content, density, lubricity, cold-flow properties and sulphur content. More details Android, Windows

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Hesselman engine

Tidaholm Hesselman engine undergoing refurbishing. The Hesselman engine is a hybrid between a petrol engine and a Diesel engine introduced by Swedish engineer Jonas Hesselman in 1925. It represented the first use of direct gasoline injection on a spark-ignition engine used to power a road going vehicle. The Hesselman engine saw use in heavy trucks and buses in models produced in the 1920s and 1930s. More details Android, Windows

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Spray nozzle

A spray nozzle is a precision device that facilitates dispersion of liquid into a spray. Nozzles are used for three purposes: to distribute a liquid over an area, to increase liquid surface area, and create impact force on a solid surface. A wide variety of spray nozzle applications use a number of spray characteristics to describe the spray. Spray nozzles can be categorized based on the energy input used to cause atomization, the breakup of the fluid into drops. Spray nozzles can have one or more outlets; a multiple outlet nozzle is known as a compound nozzle. More details Android, Windows

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Surface power density

In physics and engineering, surface power density or sometimes simply specific power is power per unit area. More details Android, Windows

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Engine tuning

For other uses, see Tuning (disambiguation). Vintage engine testing equipment that can test ignition timing, ignition dwell, manifold vacuum and exhaust emissions Engine tuning is an adjustment, modification of the internal combustion engine, or modification to its control unit, otherwise known as its ECU (Engine Control Unit). It is adjusted to yield optimal performance, to increase an engine's power output, economy, or durability. These goals may be mutually exclusive, and an engine may be detuned with respect to output (work) in exchange for better economy or longer engine life due to lessened stress on engine components. It has a long history, almost as long as the development of the automobile in general, originating with the development of early racing cars, and later, with the post-war hot-rod movement. Tuning can describe a wide variety of adjustments and modifications, from the routine adjustment of the carburetor and ignition system to significant engine overhauls. At the other end of the scale, performance tuning of an engine can involve revisiting some of the design decisions taken at quite an early stage in the development of the engine. Setting the idle speed, fuel/air mixture, carburetor balance, spark plug and distributor point gaps, and ignition timing were regular maintenance items for all older engines and the final but essential steps in setting up a racing engine. On modern engines, equipped with electronic ignition and fuel injection, some or all of these tasks are automated, although they still require periodic calibration. More details Android, Windows

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Turbocharger

"Turbo" redirects here. For the computer-animated comedy sports film, see Turbo (film). For other uses, see Turbo (disambiguation). Cut-away view of an air foil bearing-supported turbocharger A turbocharger, or turbo (colloquialism), from Greek "τύρβη" ("wake"), is a turbine-driven forced induction device that increases an internal combustion engine's efficiency and power output by forcing extra air into the combustion chamber. This improvement over a naturally aspirated engine's power output is due to the fact that the compressor can force more air—and proportionately more fuel—into the combustion chamber than atmospheric pressure (and for that matter, ram air intakes) alone. Turbochargers were originally known as turbosuperchargers when all forced induction devices were classified as superchargers. Nowadays the term "supercharger" is usually applied only to mechanically driven forced induction devices. The key difference between a turbocharger and a conventional supercharger is that a supercharger is mechanically driven by the engine, often through a belt connected to the crankshaft, whereas a turbocharger is powered by a turbine driven by the engine's exhaust gas. Compared to a mechanically driven supercharger, turbochargers tend to be more efficient, but less responsive. Twincharger refers to an engine with both a supercharger and a turbocharger. Turbochargers are commonly used on truck, car, train, aircraft, and construction equipment engines. They are most often used with Otto cycle and Diesel cycle internal combustion engines. They have also been found useful in automotive fuel cells. More details Android, Windows

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Centrifugal compressor

Centrifugal impeller with a highly polished surface likely to improve performance Jet engine cutaway showing the centrifugal compressor and other parts Inlet velocity triangles for centrifugal compressor impeller Exit velocity triangles for centrifugal compressor impeller Figure 1.1 – Aero-thermo domain of turbomachinery Figure 1.2 – Physical domain of turbomachinery Centrifugal compressors, sometimes termed radial compressors, are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. The idealized compressive dynamic turbo-machine achieves a pressure rise by adding kinetic energy/velocity to a continuous flow of fluid through the rotor or impeller. This kinetic energy is then converted to an increase in potential energy/static pressure by slowing the flow through a diffuser. The pressure rise in impeller is in most cases almost equal to the rise in the diffuser section. More details Android, Windows

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Turbo-compound engine

The Napier Nomad engine. The power-recovery turbine sits underneath a two-stroke diesel engine. A turbo-compound engine is a reciprocating engine that employs a turbine to recover energy from the exhaust gases. The turbine is usually mechanically connected to the crankshaft, as on the Wright R-3350 Duplex-Cyclone engines fitted to Douglas DC-7B and the Lockheed L-1049 Super Constellation airliners, but electric and hydraulic power recovery systems have been investigated as well. Recovery turbines increase the output of the engine without increasing its fuel consumption, thus reducing the specific fuel consumption. Turbo-compounding was used for commercial airliners and similar long-range, long-endurance roles before the introduction of high-bypass turbofan engines replaced them in this role. Most piston engines have a hot exhaust that still contains considerable undeveloped energy that could be used for propulsion if extracted. A turbine is often used to extract energy from such a stream of gasses. A conventional gas turbine is fed high-pressure, high-velocity air, extracts energy from it, and leaves as a lower-pressure, slower-moving stream. This action has the side-effect of increasing the upstream pressure, which makes it undesirable for use with a piston engine as it has the side-effect of increasing the back-pressure in the engine, which decreases scavenging of the exhaust gas from the cylinders and thereby lowers the efficiency of the piston portion of a compound engine. More details Android, Windows

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Engine knocking

"Pinging" redirects here. For other uses, see Ping (disambiguation). Knocking (also knock, detonation, spark knock, pinging or pinking) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder does not start off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel-air charge is meant to be ignited by the spark plug only, and at a precise point in the piston's stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive. Knocking should not be confused with pre-ignition – they are two separate events. However, pre-ignition is usually followed by knocking. The phenomenon of detonation was first observed and described by Harry Ricardo during experiments carried out between 1916 and 1919 to discover the reason for failures in aircraft engines. More details Android, Windows

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Compression ratio

For compression ratio in data compression, see data compression ratio. A four-stroke engine showing the stroke of the piston. The static compression ratio of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity. It is a fundamental specification for many common combustion engines. In a piston engine, it is the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, and the volume of the combustion chamber when the piston is at the top of its stroke. For example, a cylinder and its combustion chamber with the piston at the bottom of its stroke may contain 1000 cc of air (900 cc in the cylinder plus 100 cc in the combustion chamber). When the piston has moved up to the top of its stroke inside the cylinder, and the remaining volume inside the head or combustion chamber has been reduced to 100 cc, then the compression ratio would be proportionally described as 1000:100, or with fractional reduction, a 10:1 compression ratio. A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air-fuel mixture due to its higher thermal efficiency. This occurs because internal combustion engines are heat engines, and higher efficiency is created because higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. It may be more helpful to think of it as an "expansion ratio", since more expansion reduces the temperature of the exhaust gases, and therefore the energy wasted to the atmosphere. Diesel engines actually have a higher peak combustion temperature than petrol engines, but the greater expansion means they reject less heat in their cooler exhaust. Higher compression ratios will however make gasoline engines subject to engine knocking (also known as detonation) if lower octane-rated fuel is used. This can reduce efficiency or damage the engine if knock sensors are not present to modify the ignition timing. However, knock sensors have been a requirement of the OBD-II specification used in 1996 model year vehicles and newer. On the other hand, Diesel engines operate on the principle of compression ignition, so that a fuel which resists autoignition will cause late ignition, which will also lead to engine knock. More details Android, Windows