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111-600: The Vickers 6-ton tank or Vickers Mark E , also known as the "Six-tonner", was a British light tank designed in 1928 in a private project at Vickers . Though not adopted by the British Army , it was picked up by several other armed forces, and licensed by the Soviet Union as the T-26 . It was also the direct predecessor of the Polish 7TP tank. The first Mark E was built in 1928 by

222-414: A carcinogen or "probable carcinogen" and is known to increase the risk of heart and respiratory diseases. In principle, a diesel engine does not require any sort of electrical system. However, most modern diesel engines are equipped with an electrical fuel pump, and an electronic engine control unit. However, there is no high-voltage electrical ignition system present in a diesel engine. This eliminates

333-421: A design team that included the famed tank designers John Valentine Carden and Vivian Loyd . The hull was made of riveted steel plates, 1 inch (25.4 mm) thick at the front and over most of the turrets, and about 3 ⁄ 4 inch (19 mm) thick on the rear of the hull. The power was provided by an Armstrong Siddeley engine of 80–95 horsepower (60–71 kW) (depending on the version), which gave it

444-448: A diesel engine drops at lower loads, however, it does not drop quite as fast as the Otto (spark ignition) engine's. Diesel engines are combustion engines and, therefore, emit combustion products in their exhaust gas . Due to incomplete combustion, diesel engine exhaust gases include carbon monoxide , hydrocarbons , particulate matter , and nitrogen oxides pollutants. About 90 per cent of

555-516: A few degrees releasing the pressure and is controlled by a mechanical governor, consisting of weights rotating at engine speed constrained by springs and a lever. The injectors are held open by the fuel pressure. On high-speed engines the plunger pumps are together in one unit. The length of fuel lines from the pump to each injector is normally the same for each cylinder in order to obtain the same pressure delay. Direct injected diesel engines usually use orifice-type fuel injectors. Electronic control of

666-407: A finite area, and the net output of work during a cycle is positive. The fuel efficiency of diesel engines is better than most other types of combustion engines, due to their high compression ratio, high air–fuel equivalence ratio (λ) , and the lack of intake air restrictions (i.e. throttle valves). Theoretically, the highest possible efficiency for a diesel engine is 75%. However, in practice

777-452: A fuel consumption of 519 g·kW ·h . However, despite proving the concept, the engine caused problems, and Diesel could not achieve any substantial progress. Therefore, Krupp considered rescinding the contract they had made with Diesel. Diesel was forced to improve the design of his engine and rushed to construct a third prototype engine. Between 8 November and 20 December 1895, the second prototype had successfully covered over 111 hours on

888-409: A full set of valves, two-stroke diesel engines have simple intake ports, and exhaust ports (or exhaust valves). When the piston approaches bottom dead centre, both the intake and the exhaust ports are "open", which means that there is atmospheric pressure inside the cylinder. Therefore, some sort of pump is required to blow the air into the cylinder and the combustion gasses into the exhaust. This process

999-562: A heterogeneous air-fuel mixture. The torque a diesel engine produces is controlled by manipulating the air-fuel ratio (λ) ; instead of throttling the intake air, the diesel engine relies on altering the amount of fuel that is injected, and thus the air-fuel ratio is usually high. The diesel engine has the highest thermal efficiency (see engine efficiency ) of any practical internal or external combustion engine due to its very high expansion ratio and inherent lean burn, which enables heat dissipation by excess air. A small efficiency loss

1110-473: A large vehicle to carry it. Gun weight is typically the product of caliber and muzzle velocity . Large caliber guns on light tanks often sacrifice muzzle velocity in interest of saving weight. These guns are effective against close-quarter targets but lack the power and/or accuracy to effectively engage heavier vehicles at a distance. Some light tanks such as the PT-76 are amphibious , typically being propelled in

1221-403: A low-pressure loop at the bottom of the diagram. At 1 it is assumed that the exhaust and induction strokes have been completed, and the cylinder is again filled with air. The piston-cylinder system absorbs energy between 1 and 2 – this is the work needed to compress the air in the cylinder, and is provided by mechanical kinetic energy stored in the flywheel of the engine. Work output is done by

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1332-525: A machine gun for armament. At a time of limited military budgets, tankettes were relatively cheap and functioned as reconnaissance vehicles and mobile machine gun posts. In 1928, the British firm of Vickers-Armstrong started promoting another design by John Carden and Vivien Loyd as the " six-ton tank ". Although rejected by the British Army, it was bought by a large number of nations in small numbers. It formed

1443-588: A modified turret and the 47 mm (1.85 in) main gun (Type B standard). The tanks were in bad shape by 1939 because they were used in the training units over a period of five years. However, they did perform well and better than the Renault R35 , amongst others, as part of the Polish 10. Cavalry Brigade during the Invasion of Poland in 1939. The Soviets were also happy with the design and licensed it for production. However, in their case local production started as

1554-532: A more efficient replacement for stationary steam engines . Since the 1910s, they have been used in submarines and ships. Use in locomotives , buses, trucks, heavy equipment , agricultural equipment and electricity generation plants followed later. In the 1930s, they slowly began to be used in some automobiles . Since the 1970s energy crisis , demand for higher fuel efficiency has resulted in most major automakers, at some point, offering diesel-powered models, even in very small cars. According to Konrad Reif (2012),

1665-678: A notable exception being the EMD 567 , 645 , and 710 engines, which are all two-stroke. The power output of medium-speed diesel engines can be as high as 21,870 kW, with the effective efficiency being around 47-48% (1982). Most larger medium-speed engines are started with compressed air direct on pistons, using an air distributor, as opposed to a pneumatic starting motor acting on the flywheel, which tends to be used for smaller engines. Medium-speed engines intended for marine applications are usually used to power ( ro-ro ) ferries, passenger ships or small freight ships. Using medium-speed engines reduces

1776-526: A petroleum engine with glow-tube ignition in the early 1890s; he claimed against his own better judgement that his glow-tube ignition engine worked the same way Diesel's engine did. His claims were unfounded and he lost a patent lawsuit against Diesel. Other engines, such as the Akroyd engine and the Brayton engine , also use an operating cycle that is different from the diesel engine cycle. Friedrich Sass says that

1887-415: A poorer power-to-mass ratio than an equivalent petrol engine. The lower engine speeds (RPM) of typical diesel engines results in a lower power output. Also, the mass of a diesel engine is typically higher, since the higher operating pressure inside the combustion chamber increases the internal forces, which requires stronger (and therefore heavier) parts to withstand these forces. The distinctive noise of

1998-451: A real innovation: it was found that the two-man turret dramatically increased the rate of fire of either weapon, while still allowing both to be fired at the same time. This design, which they referred to as a duplex mounting , became common on almost all tanks designed after the Mark E. The British Army evaluated the Mark E, but rejected it, because it did not envision a tactical niche for such

2109-408: A regular trunk-piston. Two-stroke engines have a limited rotational frequency and their charge exchange is more difficult, which means that they are usually bigger than four-stroke engines and used to directly power a ship's propeller. Four-stroke engines on ships are usually used to power an electric generator. An electric motor powers the propeller. Both types are usually very undersquare , meaning

2220-435: A simple mechanical injection system since exact injection timing is not as critical. Most modern automotive engines are DI which have the benefits of greater efficiency and easier starting; however, IDI engines can still be found in the many ATV and small diesel applications. Indirect injected diesel engines use pintle-type fuel injectors. Early diesel engines injected fuel with the assistance of compressed air, which atomised

2331-533: A single orifice injector. The pre-chamber has the disadvantage of lowering efficiency due to increased heat loss to the engine's cooling system, restricting the combustion burn, thus reducing the efficiency by 5–10%. IDI engines are also more difficult to start and usually require the use of glow plugs. IDI engines may be cheaper to build but generally require a higher compression ratio than the DI counterpart. IDI also makes it easier to produce smooth, quieter running engines with

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2442-527: A single speed for long periods. Two-stroke engines use a combustion cycle which is completed in two strokes instead of four strokes. Filling the cylinder with air and compressing it takes place in one stroke, and the power and exhaust strokes are combined. The compression in a two-stroke diesel engine is similar to the compression that takes place in a four-stroke diesel engine: As the piston passes through bottom centre and starts upward, compression commences, culminating in fuel injection and ignition. Instead of

2553-426: A small chamber called a swirl chamber, precombustion chamber, pre chamber or ante-chamber, which is connected to the cylinder by a narrow air passage. Generally the goal of the pre chamber is to create increased turbulence for better air / fuel mixing. This system also allows for a smoother, quieter running engine, and because fuel mixing is assisted by turbulence, injector pressures can be lower. Most IDI systems use

2664-516: A source of radio frequency emissions (which can interfere with navigation and communication equipment), which is why only diesel-powered vehicles are allowed in some parts of the American National Radio Quiet Zone . To control the torque output at any given time (i.e. when the driver of a car adjusts the accelerator pedal ), a governor adjusts the amount of fuel injected into the engine. Mechanical governors have been used in

2775-400: A spark plug ( compression ignition rather than spark ignition ). In the diesel engine, only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically between 15:1 and 23:1. This high compression causes the temperature of the air to rise. At about the top of the compression stroke, fuel is injected directly into the compressed air in

2886-417: A swirl chamber or pre-chamber are called indirect injection (IDI) engines. Most direct injection diesel engines have a combustion cup in the top of the piston where the fuel is sprayed. Many different methods of injection can be used. Usually, an engine with helix-controlled mechanic direct injection has either an inline or a distributor injection pump. For each engine cylinder, the corresponding plunger in

2997-419: A top speed of 22 mph (35 km/h) on roads. Its suspension used two axles, each of which carried a two-wheel bogie to which a second set of bogies was connected with a leaf spring . It was patented by Carden in 1929 and apparently derived from a similar but simpler suspension on Light Tank Mk I which he patented a year earlier. Upward movement of either set of bogies would force the other down through

3108-422: A two-stroke ship diesel engine has a single-stage turbocharger with a turbine that has an axial inflow and a radial outflow. In general, there are three types of scavenging possible: Crossflow scavenging is incomplete and limits the stroke, yet some manufacturers used it. Reverse flow scavenging is a very simple way of scavenging, and it was popular amongst manufacturers until the early 1980s. Uniflow scavenging

3219-420: A variety of names, including the " combat car ". Early light tank designs were generally better armed and armored than armored cars , but used tracks in order to provide better cross-country mobility. The light tank has been one of the few tank variants to survive the development of the main battle tank —in which technological advancements have rendered all previous weight variants obsolete—and has seen use in

3330-473: A variety of roles including the support of light airborne or amphibious forces and reconnaissance. Modified IFVs are assuming these roles in many militaries due to their immediate availability, and as a cheaper versatile alternative to developing and fielding a pure light tank. In World War I , industrial initiative also led to swift advances. The car industry, already used to vehicle mass production and having much more experience in vehicle layout, designed

3441-457: A vehicle, preferring a combination of medium tanks and tankettes. Vickers then started advertising the design to all buyers, and soon received a trickle of orders eventually including the USSR , Greece, Poland, Bolivia, Siam , Finland, Portugal, China and Bulgaria. Thailand purchased 36 Vickers Medium Dragon Mark IVs, and QF 2-pounder naval guns were added to turn them into self-propelled guns used in

Vickers 6-ton - Misplaced Pages Continue

3552-461: Is a combustion engine that is more efficient than a diesel engine, but due to its mass and dimensions, is unsuitable for many vehicles, including watercraft and some aircraft . The world's largest diesel engines put in service are 14-cylinder, two-stroke marine diesel engines; they produce a peak power of almost 100 MW each. Diesel engines may be designed with either two-stroke or four-stroke combustion cycles . They were originally used as

3663-423: Is a simplified and idealised representation of the events involved in a diesel engine cycle, arranged to illustrate the similarity with a Carnot cycle . Starting at 1, the piston is at bottom dead centre and both valves are closed at the start of the compression stroke; the cylinder contains air at atmospheric pressure. Between 1 and 2 the air is compressed adiabatically – that is without heat transfer to or from

3774-568: Is a specialized light tank –amphibious with sufficient firepower to engage other reconnaissance vehicles, but very lightly armored. The US fielded small numbers of the M41 Walker Bulldog with a high velocity 76mm gun, and better armor, but it suffered from range limits, and its weight was too heavy for most air transport of the day. The US M551 Sheridan had similar strengths and weaknesses, but could also be airdropped, either by parachute or LAPES . The French had their AMX-13 light tank, which

3885-431: Is also avoided compared with non-direct-injection gasoline engines, as unburned fuel is not present during valve overlap, and therefore no fuel goes directly from the intake/injection to the exhaust. Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) can reach effective efficiencies of up to 55%. The combined cycle gas turbine (Brayton and Rankine cycle)

3996-561: Is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression ; thus, the diesel engine is called a compression-ignition engine (CI engine). This contrasts with engines using spark plug -ignition of the air-fuel mixture, such as a petrol engine ( gasoline engine) or a gas engine (using a gaseous fuel like natural gas or liquefied petroleum gas ). Diesel engines work by compressing only air, or air combined with residual combustion gases from

4107-403: Is approximately 5 MW. Medium-speed engines are used in large electrical generators, railway diesel locomotives , ship propulsion and mechanical drive applications such as large compressors or pumps. Medium speed diesel engines operate on either diesel fuel or heavy fuel oil by direct injection in the same manner as low-speed engines. Usually, they are four-stroke engines with trunk pistons;

4218-429: Is called scavenging . The pressure required is approximately 10-30 kPa. Due to the lack of discrete exhaust and intake strokes, all two-stroke diesel engines use a scavenge blower or some form of compressor to charge the cylinders with air and assist in scavenging. Roots-type superchargers were used for ship engines until the mid-1950s, however since 1955 they have been widely replaced by turbochargers. Usually,

4329-404: Is done on the system to which the engine is connected. During this expansion phase the volume of the gas rises, and its temperature and pressure both fall. At 4 the exhaust valve opens, and the pressure falls abruptly to atmospheric (approximately). This is unresisted expansion and no useful work is done by it. Ideally the adiabatic expansion should continue, extending the line 3–4 to the right until

4440-464: Is more complicated to make but allows the highest fuel efficiency; since the early 1980s, manufacturers such as MAN and Sulzer have switched to this system. It is standard for modern marine two-stroke diesel engines. So-called dual-fuel diesel engines or gas diesel engines burn two different types of fuel simultaneously , for instance, a gaseous fuel and diesel engine fuel. The diesel engine fuel auto-ignites due to compression ignition, and then ignites

4551-504: The EU average for diesel cars at the time accounted for half of newly registered cars. However, air pollution and overall emissions are more difficult to control in diesel engines compared to gasoline engines, and the use of diesel auto engines in the U.S. is now largely relegated to larger on-road and off-road vehicles . Though aviation has traditionally avoided using diesel engines, aircraft diesel engines have become increasingly available in

Vickers 6-ton - Misplaced Pages Continue

4662-622: The M2 light tank series. These light tanks were mechanically very reliable, with good mobility. However, they had a high silhouette, and only a few saw combat. The M3 Stuart series was an improvement of the M2 with better armor. The new medium tank just entering production in 1940 was the M2A1. This was a poor design with thin armor and a high silhouette. The M3 Stuart saw use in the North African Campaign but

4773-450: The Nomonhan fighting, which lasted from about May through September 1939. The Japanese Type 95 Ha-Go light tank was equipped with a diesel engine , and although mounting a 37 mm cannon, it was a low velocity gun with a maximum effective range of about 700 meters. However, this conflict would be instrumental in developing the famous T-34 medium tank. Germany's armored Panzer force

4884-465: The T-26 , and eventually over 12,000 were built in various versions. The Soviet early twin-turret T-26s had 7.62 mm (0.3 in) DT machine guns in each turret, or a mix of one machine gun turret and one 37 mm gun turret. Later, more common versions mounted a 45 mm (1.77 in) gun and two DT machine guns. The final versions of the T-26 had welded construction and, eventually, sloped armour on

4995-694: The United Kingdom , and the United States for "Method of and Apparatus for Converting Heat into Work". In 1894 and 1895, he filed patents and addenda in various countries for his engine; the first patents were issued in Spain (No. 16,654), France (No. 243,531) and Belgium (No. 113,139) in December 1894, and in Germany (No. 86,633) in 1895 and the United States (No. 608,845) in 1898. Diesel

5106-585: The battle of Guadalajara (1937), captured some of these tanks which served as models for their M11/39 and M13/40 medium tanks. In 1939, during the Soviet-Finnish Winter War , the Finnish armoured forces consisted of around thirty-two obsolete Renault FT tanks, some Vickers-Carden-Lloyd Mk. IVs and Model 33s , which were equipped with machine guns, and 26 Vickers Armstrongs 6-ton tanks. The latter had been re-equipped with 37 mm Bofors AT-guns after

5217-509: The 1940-41 Franco-Thai War . Vickers built a total of 153 (the most common figure) Mark Es. Experience with the Polish machines showed that the engine tended to overheat due to poor airflow over the air-cooled engine. This was addressed by the addition of large air vents on either side of the hull. For a new Belgian order the design was modified to use the Rolls-Royce Phantom II water-cooled engine instead. This engine would not fit in

5328-416: The 21st century. Since the late 1990s, for various reasons—including the diesel's inherent advantages over gasoline engines, but also for recent issues peculiar to aviation—development and production of diesel engines for aircraft has surged, with over 5,000 such engines delivered worldwide between 2002 and 2018, particularly for light airplanes and unmanned aerial vehicles . In 1878, Rudolf Diesel , who

5439-504: The Army as the Dragon, Medium Mark IV , while China purchased 23 and India 18. Poland purchased 38 Type A tanks, spare parts and license for the local production. The Poles modified their vehicles with larger air intakes, their own machine guns , 360-degree Gundlach periscopes , and five or more with added two-way radios, before deciding to make their own tank that would address the shortcomings of

5550-595: The British Light Tank Mk VI , French Renault R35 , German Panzer I , Italian L3/35 (classified as a light tank by the Royal Italian Army , a tankette by others), Japanese Type 95 Ha-Go light tank , Soviet T-26 , and American M2 light tank . The Soviet BT tanks were the most advanced in the 1930s, extremely fast and mounting high velocity 45 mm cannons. Their only drawback were their petrol engines which caught fire often and easily during

5661-450: The Carnot cycle. Diesel was also introduced to a fire piston , a traditional fire starter using rapid adiabatic compression principles which Linde had acquired from Southeast Asia . After several years of working on his ideas, Diesel published them in 1893 in the essay Theory and Construction of a Rational Heat Motor . Diesel was heavily criticised for his essay, but only a few found

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5772-595: The Cold War era was the Swedish Ikv 91 (classified as an assault gun by Sweden). It had a low-pressure 90mm gun, strong armor against 20mm grenades, and it was fully amphibious. Light tanks, such as the PT-76 , continue to play a small role in tank warfare , although many are losing favor to cheaper, faster, and lighter armored cars . The light tank still fills an important niche in many armies, especially for nations with airborne divisions, Marine Infantry, or those without

5883-689: The Finns rearmed their Vickers 6-ton tanks with Soviet 45 mm guns and re-designated them as T-26Es . These tanks were used by the Finnish Army during the Continuation War . Nineteen rebuilt Vickers tanks, along with 75 T-26s continued in Finnish service after the end of the Second World War . Some of these tanks were kept as training tanks until 1959, when they were finally phased out and replaced by newer British and Soviet tanks. Background: History of

5994-400: The amount of fuel injected into the engine. Due to the amount of air being constant (for a given RPM) while the amount of fuel varies, very high ("lean") air-fuel ratios are used in situations where minimal torque output is required. This differs from a petrol engine, where a throttle is used to also reduce the amount of intake air as part of regulating the engine's torque output. Controlling

6105-513: The armor in contemporary light tanks is modular, sometimes up to three configurations. The flat hull necessary for amphibious light tanks to plane across the surface of the water is not nearly as blast-resistant as the V-shaped hull. It has been suggested that underbelly armor appliqué could be applied after the light tanks come ashore and before they encounter explosive devices. A gun capable of defeating modern tanks at reasonable ranges requires

6216-585: The basis of the Soviet T-26 (around 10,000 built) and the Polish 7TP tank and influenced the Italian Fiat M11/39 . The British Army did not use the design as a light tank themselves but a developed version of the Carden Loyd tankette as the starting point for a series of British light tanks intended for use in imperial policing and expeditionary warfare. As the only tank fit for immediate manufacture, it

6327-470: The bore is smaller than the stroke. Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) often have an effective efficiency of up to 55%. Like medium-speed engines, low-speed engines are started with compressed air, and they use heavy oil as their primary fuel. Four-stroke engines use the combustion cycle described earlier. Most smaller diesels, for vehicular use, for instance, typically use

6438-448: The combustion chamber, the droplets continue to vaporise from their surfaces and burn, getting smaller, until all the fuel in the droplets has been burnt. Combustion occurs at a substantially constant pressure during the initial part of the power stroke. The start of vaporisation causes a delay before ignition and the characteristic diesel knocking sound as the vapour reaches ignition temperature and causes an abrupt increase in pressure above

6549-418: The combustion chamber. This may be into a (typically toroidal ) void in the top of the piston or a pre-chamber depending upon the design of the engine. The fuel injector ensures that the fuel is broken down into small droplets, and that the fuel is distributed evenly. The heat of the compressed air vaporises fuel from the surface of the droplets. The vapour is then ignited by the heat from the compressed air in

6660-425: The compressed gas. Combustion and heating occur between 2 and 3. In this interval the pressure remains constant since the piston descends, and the volume increases; the temperature rises as a consequence of the energy of combustion. At 3 fuel injection and combustion are complete, and the cylinder contains gas at a higher temperature than at 2. Between 3 and 4 this hot gas expands, again approximately adiabatically. Work

6771-452: The compression ratio in a spark-ignition engine where fuel and air are mixed before entry to the cylinder is limited by the need to prevent pre-ignition , which would cause engine damage. Since only air is compressed in a diesel engine, and fuel is not introduced into the cylinder until shortly before top dead centre ( TDC ), premature detonation is not a problem and compression ratios are much higher. The pressure–volume diagram (pV) diagram

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6882-473: The compression required for his cycle: By June 1893, Diesel had realised his original cycle would not work, and he adopted the constant pressure cycle. Diesel describes the cycle in his 1895 patent application. Notice that there is no longer a mention of compression temperatures exceeding the temperature of combustion. Now it is simply stated that the compression must be sufficient to trigger ignition. In 1892, Diesel received patents in Germany , Switzerland ,

6993-416: The concept of air-blast injection from George B. Brayton , albeit that Diesel substantially improved the system. On 17 February 1894, the redesigned engine ran for 88 revolutions – one minute; with this news, Maschinenfabrik Augsburg's stock rose by 30%, indicative of the tremendous anticipated demands for a more efficient engine. On 26 June 1895, the engine achieved an effective efficiency of 16.6% and had

7104-424: The cost of smaller ships and increases their transport capacity. In addition to that, a single ship can use two smaller engines instead of one big engine, which increases the ship's safety. Low-speed diesel engines are usually very large in size and mostly used to power ships . There are two different types of low-speed engines that are commonly used: Two-stroke engines with a crosshead, and four-stroke engines with

7215-598: The diesel engine is Diesel's "very own work" and that any "Diesel myth" is " falsification of history ". Diesel sought out firms and factories that would build his engine. With the help of Moritz Schröter and Max Gutermuth  [ de ] , he succeeded in convincing both Krupp in Essen and the Maschinenfabrik Augsburg . Contracts were signed in April 1893, and in early summer 1893, Diesel's first prototype engine

7326-417: The efficiency is much lower, with efficiencies of up to 43% for passenger car engines, up to 45% for large truck and bus engines, and up to 55% for large two-stroke marine engines. The average efficiency over a motor vehicle driving cycle is lower than the diesel engine's peak efficiency (for example, a 37% average efficiency for an engine with a peak efficiency of 44%). That is because the fuel efficiency of

7437-408: The environment – by the rising piston. (This is only approximately true since there will be some heat exchange with the cylinder walls .) During this compression, the volume is reduced, the pressure and temperature both rise. At or slightly before 2 (TDC) fuel is injected and burns in the compressed hot air. Chemical energy is released and this constitutes an injection of thermal energy (heat) into

7548-406: The exhaust (known as exhaust gas recirculation , "EGR"). Air is inducted into the chamber during the intake stroke, and compressed during the compression stroke. This increases air temperature inside the cylinder so that atomised diesel fuel injected into the combustion chamber ignites. With the fuel being injected into the air just before combustion, the dispersion of fuel is uneven; this is called

7659-539: The fact that light tank platoons were not expected to function as a reconnaissance unit, they could be used for reconnaissance purposes. In this role, they were expected to remain behind the main reconnaissance force as the support element and augment the firepower whenever enemy contact was made. The British withdrew their light tank designs from their armored divisions early in the war, but used some later designs for minor amphibious operations and airborne operations. In general they used armored cars for reconnaissance and

7770-482: The first assault on the Soviet lines – to make matters worse, one of the tanks was forced to stop, unable to cross a wide trench. The remaining five continued onwards a few hundred metres but ran into dozens of Soviet tanks in the village of Honkaniemi. The Finnish tanks managed to knock out three Soviet tanks but were soon themselves knocked-out. In the skirmishes that followed, the Finns lost two more Vickers tanks. In 1941,

7881-453: The first practical light tanks in 1916, a class largely neglected by the British. Renault 's small tank design, the FT , was the first tank to incorporate a top-mounted turret with a full rotation. The FT was in many respects the first truly modern tank having a layout that has been followed by almost all designs ever since: driver at the front; main armament in a fully rotating turret on top; engine at

7992-463: The four-stroke cycle. This is due to several factors, such as the two-stroke design's narrow powerband which is not particularly suitable for automotive use and the necessity for complicated and expensive built-in lubrication systems and scavenging measures. The cost effectiveness (and proportion of added weight) of these technologies has less of an impact on larger, more expensive engines, while engines intended for shipping or stationary use can be run at

8103-612: The fuel and forced it into the engine through a nozzle (a similar principle to an aerosol spray). The nozzle opening was closed by a pin valve actuated by the camshaft . Although the engine was also required to drive an air compressor used for air-blast injection, the efficiency was nonetheless better than other combustion engines of the time. However the system was heavy and it was slow to react to changing torque demands, making it unsuitable for road vehicles. A unit injector system, also known as "Pumpe-Düse" ( pump-nozzle in German) combines

8214-697: The fuel injection transformed the direct injection engine by allowing much greater control over the combustion. Common rail (CR) direct injection systems do not have the fuel metering, pressure-raising and delivery functions in a single unit, as in the case of a Bosch distributor-type pump, for example. A high-pressure pump supplies the CR. The requirements of each cylinder injector are supplied from this common high pressure reservoir of fuel. An Electronic Diesel Control (EDC) controls both rail pressure and injections depending on engine operating conditions. The injectors of older CR systems have solenoid -driven plungers for lifting

8325-405: The fuel pump measures out the correct amount of fuel and determines the timing of each injection. These engines use injectors that are very precise spring-loaded valves that open and close at a specific fuel pressure. Separate high-pressure fuel lines connect the fuel pump with each cylinder. Fuel volume for each single combustion is controlled by a slanted groove in the plunger which rotates only

8436-461: The gaseous fuel. Such engines do not require any type of spark ignition and operate similar to regular diesel engines. The fuel is injected at high pressure into either the combustion chamber , "swirl chamber" or "pre-chamber," unlike petrol engines where the fuel is often added in the inlet manifold or carburetor . Engines where the fuel is injected into the main combustion chamber are called direct injection (DI) engines, while those which use

8547-474: The hatch. Some light tanks, such as the M551 Sheridan , ZTQ-15 and 2S25 Sprut-SD armored reconnaissance vehicle, could be rigged for low- velocity airdrops from transport aircraft . With this method the tank is pulled out of the aircraft by brake chutes and skids to a stop. The crew does not ride in the tank during extraction, but parachutes from another plane. Upon landing, they go to their tank, release

8658-589: The hull and turret. Because the T-26 was in such wide use and was a reliable platform, a variety of engineer vehicles were built on the chassis, including flamethrowers and bridgelayers. A novel radio-controlled demolition tank was built on the T-26 chassis also. During the Spanish Civil War the Soviet Union sent the T-26 to the Republican Army. The Italians, after suffering losses from Republican T-26s during

8769-419: The injection needle, whilst newer CR injectors use plungers driven by piezoelectric actuators that have less moving mass and therefore allow even more injections in a very short period of time. Early common rail system were controlled by mechanical means. The injection pressure of modern CR systems ranges from 140 MPa to 270 MPa. An indirect diesel injection system (IDI) engine delivers fuel into

8880-553: The injector and fuel pump into a single component, which is positioned above each cylinder. This eliminates the high-pressure fuel lines and achieves a more consistent injection. Under full load, the injection pressure can reach up to 220 MPa. Unit injectors are operated by a cam and the quantity of fuel injected is controlled either mechanically (by a rack or lever) or electronically. Due to increased performance requirements, unit injectors have been largely replaced by common rail injection systems. The average diesel engine has

8991-542: The last of the light tank designs, the light tank Mk VIII "Harry Hopkins", was produced only in small numbers. The Japanese made extensive use of light tanks that were much better suited to jungle warfare than larger designs, such as the Type 95 Ha-Go light tank. Light tanks continued to be built, but for very limited roles such as amphibious reconnaissance, support of airborne units , and in rapid-intervention forces that were not expected to face enemy tanks. The Soviet PT-76

9102-603: The lines, and drive it away. Background: History of the tank , Tank classification , Tanks in World War I Background: History of the tank , Tank classification , interwar period Background: History of the tank , Tank classification , Tanks in the Cold War Background: History of the tank , Tank classification Diesel engine The diesel engine , named after the German engineer Rudolf Diesel ,

9213-403: The low priority given to the army meant that there were few resources for building tanks. The US Army instead developed and tested tank components such as suspensions, tracks, and transmissions. This paid off when production had to be initiated on the outbreak of war. At the start of World War II, the majority of all of the great powers' tank forces consisted of light designs. The most common were

9324-476: The mistake that he made; his rational heat motor was supposed to utilise a constant temperature cycle (with isothermal compression) that would require a much higher level of compression than that needed for compression ignition. Diesel's idea was to compress the air so tightly that the temperature of the air would exceed that of combustion. However, such an engine could never perform any usable work. In his 1892 US patent (granted in 1895) #542846, Diesel describes

9435-507: The number of radios. Throughout the interwar period the US produced only a few hundred tanks. From the end of World War I to 1935, only 15 tanks were produced. Most were derivatives or foreign designs or very poor quality private designs. The Christie designs were among the few better examples, but the US Army acquired only three Christies and did not pursue the idea any further. Budget limitations and

9546-505: The original Vickers design. This resulted in the 7TP , which was nearly 10 tons in weight. The Poles also, besides the aforementioned telescope, added a liquid-cooled diesel engine as well as better armour protection, better ventilation, two-way radios, a 37 mm (1.46 in) Polish version of the Bofors anti-tank gun, and a bigger crew compartment. Out of 38 original two-turreted tanks, 22 were later converted to single turret version with

9657-530: The outbreak of the war. Only 13 of these tanks managed to get to the front in time to participate in the battles. At the Battle of Honkaniemi on 26 February 1940, the Finns employed their Vickers tanks for the first – and only – time against Soviet armour during the Winter War. The results were disastrous. Of the thirteen available Finnish Vickers 6-ton tanks only six were in fighting condition and able to participate in

9768-534: The past, however electronic governors are more common on modern engines. Mechanical governors are usually driven by the engine's accessory belt or a gear-drive system and use a combination of springs and weights to control fuel delivery relative to both load and speed. Electronically governed engines use an electronic control unit (ECU) or electronic control module (ECM) to control the fuel delivery. The ECM/ECU uses various sensors (such as engine speed signal, intake manifold pressure and fuel temperature) to determine

9879-477: The piston (not shown on the P-V indicator diagram). When combustion is complete the combustion gases expand as the piston descends further; the high pressure in the cylinder drives the piston downward, supplying power to the crankshaft. As well as the high level of compression allowing combustion to take place without a separate ignition system, a high compression ratio greatly increases the engine's efficiency. Increasing

9990-403: The piston-cylinder combination between 2 and 4. The difference between these two increments of work is the indicated work output per cycle, and is represented by the area enclosed by the pV loop. The adiabatic expansion is in a higher pressure range than that of the compression because the gas in the cylinder is hotter during expansion than during compression. It is for this reason that the loop has

10101-417: The pollutants can be removed from the exhaust gas using exhaust gas treatment technology. Road vehicle diesel engines have no sulfur dioxide emissions, because motor vehicle diesel fuel has been sulfur-free since 2003. Helmut Tschöke argues that particulate matter emitted from motor vehicles has negative impacts on human health. The particulate matter in diesel exhaust emissions is sometimes classified as

10212-821: The preferred choice for infantry support in Equatorial nations. Post–Cold War light tanks include the Stingray , ZTQ-15 , M8 Armored Gun System and Kaplan MT / Harimau . Light tanks based on infantry fighting vehicles chassis include the CV90 105T, 2S25 Sprut-SD , Tanque Argentino Mediano , ASCOD LT 105 , and Sabrah . The modern light tank supplements the main battle tank in expeditionary roles and situations where all major threats have been neutralized and excessive weight in armor and armament would only hinder mobility and cost more money to operate. They have also been used for reconnaissance and, in some cases, infantry support. Typically,

10323-408: The pressure falls to that of the surrounding air, but the loss of efficiency caused by this unresisted expansion is justified by the practical difficulties involved in recovering it (the engine would have to be much larger). After the opening of the exhaust valve, the exhaust stroke follows, but this (and the following induction stroke) are not shown on the diagram. If shown, they would be represented by

10434-518: The rear, and had to be mounted along the left side of the tank, requiring the turret to be moved to the right and rearward. One example of the resulting Mark F was tested by Belgium, but rejected. Nevertheless, the new hull was used, with the older engine, in the sales to Finland and Siam. The Mark E was also developed as a cargo vehicle, and purchased by the British Army in small numbers as artillery tractors to haul their large BL 60-pounder (127 mm; 5 in) field guns . Twelve were ordered by

10545-443: The rear. Previous models had been "box tanks", with a single crowded space combining the role of engine room, fighting compartment, ammunition stock and driver's cabin. The FT had the largest production run of any tank of the war, over 3,700 (mostly in 1918), and was more numerous than all British and German tanks combined. The Carden Loyd tankette and its derivatives were adopted by several nations as small tracked vehicles carrying

10656-468: The resources and funding for main battle tanks . They have important advantages over heavier tanks in Southeast Asia and other nations in the Equatorial region. Their compact dimensions and short-to-nonexistent barrel overhang lets them maneuver through thick rain forests, and their weight reduces the risk of getting stuck in mud, and simplifies recovery of stuck or damaged tanks. This makes the light tank

10767-400: The spring. This was considered to be a fairly good system for the time and offered better than normal cross-country performance although it could not compare with the contemporary Christie suspension . High strength steel tracks gave over 3,000 miles (4,800 km) of life which was considerably better than most designs of the era. The tank was built in two versions: The Type B proved to be

10878-597: The tank , Tank classification , interwar period Background: British armoured fighting vehicle production during World War II , Tanks in the British Army Light tank The fast light tank was a major feature of the pre– World War II army buildup, where it was expected they would be used to exploit breakthroughs in enemy lines created by slower, heavier tanks, with the goal of disrupting communications and supply lines. Numerous small tank designs and " tankettes " were developed during this period and known under

10989-539: The test bench. In the January 1896 report, this was considered a success. In February 1896, Diesel considered supercharging the third prototype. Imanuel Lauster , who was ordered to draw the third prototype " Motor 250/400 ", had finished the drawings by 30 April 1896. During summer that year the engine was built, it was completed on 6 October 1896. Tests were conducted until early 1897. First public tests began on 1 February 1897. Moritz Schröter 's test on 17 February 1897

11100-890: The timing of the start of injection of fuel into the cylinder is similar to controlling the ignition timing in a petrol engine. It is therefore a key factor in controlling the power output, fuel consumption and exhaust emissions. There are several different ways of categorising diesel engines, as outlined in the following sections. Günter Mau categorises diesel engines by their rotational speeds into three groups: High-speed engines are used to power trucks (lorries), buses , tractors , cars , yachts , compressors , pumps and small electrical generators . As of 2018, most high-speed engines have direct injection . Many modern engines, particularly in on-highway applications, have common rail direct injection . On bigger ships, high-speed diesel engines are often used for powering electric generators. The highest power output of high-speed diesel engines

11211-399: The vehicle, or even a troop, had to load and aim the turret gun. The lack of radios with the light tanks was not seen as a major drawback, since French doctrine called for slow-paced, deliberate maneuvers in close conformance to plans. The role of small unit leaders was to execute plans, not to take the initiative in combat. In 1939, a belated effort was made to improve flexibility and increase

11322-417: The water by hydrojets or by their tracks. Most amphibious light tanks weigh little and often utilize aluminum armor. Some light tanks require no modifications for river crossings. Crews simply raise the easily accessible cloth sides around the hull, cover the hatches, turn on the bilge pump and shift the transmission to water operations. Often, a fold down trim vane is erected to stop water from flooding into

11433-481: Was a key element in the expansion of the British Army in the period leading up to the outbreak of war. In general, French tanks of the 1930s were well-armored, innovative vehicles that owed little to foreign designs. However, the light tanks lacked firepower and almost all French tanks were handicapped by their one-man turrets, even the larger tanks such as the Char B1 , which overworked the commander who, besides directing

11544-524: Was a student at the "Polytechnikum" in Munich , attended the lectures of Carl von Linde . Linde explained that steam engines are capable of converting just 6–10% of the heat energy into work, but that the Carnot cycle allows conversion of much more of the heat energy into work by means of isothermal change in condition. According to Diesel, this ignited the idea of creating a highly efficient engine that could work on

11655-488: Was attacked and criticised over several years. Critics claimed that Diesel never invented a new motor and that the invention of the diesel engine is fraud. Otto Köhler and Emil Capitaine  [ de ] were two of the most prominent critics of Diesel's time. Köhler had published an essay in 1887, in which he describes an engine similar to the engine Diesel describes in his 1893 essay. Köhler figured that such an engine could not perform any work. Emil Capitaine had built

11766-472: Was built in Augsburg . On 10 August 1893, the first ignition took place, the fuel used was petrol. In winter 1893/1894, Diesel redesigned the existing engine, and by 18 January 1894, his mechanics had converted it into the second prototype. During January that year, an air-blast injection system was added to the engine's cylinder head and tested. Friedrich Sass argues that, it can be presumed that Diesel copied

11877-515: Was designed for its capability to be quickly air-dropped for use with paratroopers and also able to support lightly armed infantry and perform force-reconnaissance effectively. The British FV101 Scorpion , the fire support variant of the Combat Vehicle Reconnaissance (Tracked) series of vehicles that replaced armored cars in British service, has been described as a light tank and was sold to many smaller nations. Another light tank in

11988-563: Was not especially impressive at the start of the war. In the invasions of Poland and France , the German forces were mostly made up of the Panzer I and Panzer II light tanks. The Panzer I was little more than a training vehicle armed only with machine guns; the Panzer II with a 20 mm cannon. The Panzer division also included some Czech designed light tanks—the Panzer 35(t) and the Panzer 38(t) . American light tank development started with

12099-459: Was relegated to reconnaissance as soon as US-built medium tanks became available. Further light tank development in the war led to the improved M5 Stuart and then included the M24 Chaffee . Light tanks were issued to tank battalions (one of the four companies was a light tank company), light tank battalions and cavalry reconnaissance squadrons. The original role of the light tank in these formations

12210-616: Was similar to medium tanks and they were expected to engage enemy armor with AP rounds and enemy positions with HE rounds. As a result, tank gunnery training for light and medium tankers was common. US Army Field Manuals written before 1944 clearly show that light tanks were to be part of an armored assault on enemy positions, and examples of fire on enemy armor were in these manuals. When pursuing an enemy, Light Tank Battalions were expected to move parallel with enemy columns and, together with accompanying infantry and engineer units, seize "critical terrain that will block hostile retreat". Despite

12321-424: Was the main test of Diesel's engine. The engine was rated 13.1 kW with a specific fuel consumption of 324 g·kW ·h , resulting in an effective efficiency of 26.2%. By 1898, Diesel had become a millionaire. The characteristics of a diesel engine are The diesel internal combustion engine differs from the gasoline powered Otto cycle by using highly compressed hot air to ignite the fuel rather than using

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