Honda
Honda Motor Co. Ltd. is a Japanese public multinational conglomerate corporation primarily known as a manufacturer of automobiles, aircraft and power equipment. Honda became the second-largest Japanese automobile manufacturer in 2001, Honda was the eighth largest automobile manufacturer in the world behind General Motors, Volkswagen Group, Hyundai Motor Group, Nissan, and PSA Peugeot Citroën in 2011. Honda was the first Japanese automobile manufacturer to release a luxury brand, Acura. Aside from their automobile and motorcycle businesses, Honda manufactures garden equipment, marine engines, personal watercraft and power generators. Since 1986, Honda has been involved with artificial intelligence/robotics research and they have ventured into aerospace with the establishment of GE Honda Aero Engines in 2004 and the Honda HA-420 HondaJet, which began production in 2012. Honda has three joint-ventures in China, in 2013, Honda invested about 5. 7% of its revenues in research and development. Also in 2013, Honda became the first Japanese automaker to be a net exporter from the United States, exporting 108,705 Honda and Acura models, throughout his life, Hondas founder, Soichiro Honda had an interest in automobiles.
He worked as a mechanic at the Art Shokai garage, where he tuned cars, in 1937, with financing from his acquaintance Kato Shichirō, Honda founded Tōkai Seiki to make piston rings working out of the Art Shokai garage. After initial failures, Tōkai Seiki won a contract to supply piston rings to Toyota, Honda aided the war effort by assisting other companies in automating the production of military aircraft propellers. The relationships Honda cultivated with personnel at Toyota, Nakajima Aircraft Company, with a staff of 12 men working in a 16 m2 shack, they built and sold improvised motorized bicycles, using a supply of 500 two-stroke 50 cc Tohatsu war surplus radio generator engines. When the engines ran out, Honda began building their own copy of the Tohatsu engine and this was the Honda A-Type, nicknamed the Bata Bata for the sound the engine made. In 1949, the Honda Technical Research Institute was liquidated for ¥1,000,000, or about US$5,000 today, at about the same time Honda hired engineer Kihachiro Kawashima, and Takeo Fujisawa who provided indispensable business and marketing expertise to complement Soichiro Hondas technical bent.
The close partnership between Soichiro Honda and Fujisawa lasted until they stepped down together in October 1973, the first complete motorcycle, with both the frame and engine made by Honda, was the 1949 D-Type, the first Honda to go by the name Dream. Honda Motor Company grew in a time to become the worlds largest manufacturer of motorcycles by 1964. The first production automobile from Honda was the T360 mini pick-up truck, powered by a small 356-cc straight-4 gasoline engine, it was classified under the cheaper Kei car tax bracket. The first production car from Honda was the S500 sports car and its chain-driven rear wheels pointed to Hondas motorcycle origins. Over the next few decades, Honda worked to expand its line and expanded operations. In 1986, Honda introduced the successful Acura brand to the American market in an attempt to ground in the luxury vehicle market
Flat engine
A flat engine is an internal combustion engine with horizontally-opposed cylinders. Typically, the layout has cylinders arranged in two banks on either side of a crankshaft and is otherwise known as the boxer. The concept was patented in 1896 by engineer Karl Benz, who called it the contra engine, a boxer engine should not be confused with the opposed-piston engine, in which each cylinder has two pistons but no cylinder head. Also, if an engine is canted 90 degrees into the horizontal plane. Horizontal inline engines are common in industrial applications such as underfloor mounting for buses. True boxers have each crankpin controlling only one piston/cylinder while the 180° engines, the 180° engine, which may be thought of as a type of V engine, is quite uncommon as it has all of the disadvantages of a flat engine, and few of the advantages. In 1896, Karl Benz invented the first internal combustion engine with opposed pistons. He called it the engine, as the action of each side opposed the action of the other.
This design has since called the boxer engine because each pair of pistons moves in. The boxer engine has pairs of pistons reaching TDC simultaneously and these engines do not require a balance shaft or counterweights on the crankshaft to balance the weight of the reciprocating parts, which are required in most other engine configurations. However, in the case of engines with fewer than six cylinders. Other engine configurations with natural dynamic balance include the straight-six, the straight-eight, the V12, Boxer engines tend to be noisier than other common engines for both intrinsic and other reasons. In cars, valve clatter from the compartment is not damped by air filters or other components. Multi-cylinder boxer layouts have proved to be suited as light aircraft engines, as exemplified by Continental, Rotax, Jabiru. An important factor in aircraft use is the flat engines absence of vibration, general aviation aircraft often use air-cooled flat-four and flat-six engines made by companies such as Lycoming and Continental.
Ultralight and microlight aircraft often use such as the Rotax 912. During the Second World War, Boxer engines were used as a motor for the first German jet engines to power up the engine at cranking speed. It was a short stroke design so it could fit in the hub of the turbine compressor
Exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, petrol, biodiesel blends, diesel fuel, fuel oil, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack and it often disperses downwind in a pattern called an exhaust plume. A2013 study by MIT indicates that 53,000 early deaths occur per year in the United States alone because of vehicle emissions. According to another study from the university, traffic fumes alone cause the death of 5,000 people every year just in the United Kingdom. The largest part of most combustion gas is nitrogen, water vapor, and carbon dioxide, Exhaust gas temperature is important to the functioning of the catalytic converter of an internal combustion engine. It may be measured by an exhaust gas temperature gauge, EGT is a measure of engine health in gas-turbine engines. During the first two minutes after starting the engine of a car that has not been operated for several hours, inefficient catalytic converter under cold conditions, Catalytic converters are very inefficient until up to their operating temperature.
This time has much reduced by moving the converter closer to the exhaust manifold. The small converter handles the start-up emissions, which enough time for the larger main converter to heat up. Further improvements can be realised in many ways, including heating, thermal battery, chemical reaction preheating, flame heating. The requirements were phased in beginning with 2004 vehicles and all new cars, in spark-ignition engines the gases resulting from combustion of the fuel and air mix are called exhaust gases. The composition varies from petrol to diesel engines, but is around these levels, The 10% oxygen for diesel is likely if the engine was idling and it is much less if the engine is running under load. People exposed to it should wear a gas mask, in aircraft gas turbine engines, exhaust gas temperature is a primary measure of engine health. Typically the EGT is compared with an engine power indication called engine pressure ratio. For example, at full power EPR there will be a maximum permitted EGT limit, once an engine reaches a stage in its life where it reaches this EGT limit, the engine will require specific maintenance in order to rectify the problem.
The amount the EGT is below the EGT limit is called EGT margin, the EGT margin of an engine will be greatest when the engine is new, or has been overhauled. For most airlines, this information is monitored remotely by the airline maintenance department by means of ACARS. In jet engines and rocket engines, exhaust from propelling nozzles which in some applications shows shock diamonds, Flue gas Flue gas emissions from fossil fuel combustion In steam engine terminology the exhaust is steam that is now so low in pressure that it can no longer do useful work
Overhead camshaft
Compared to OHV pushrod systems with the same number of valves, the reciprocating components of the OHC system are fewer and have a lower overall mass. Though the system drives the camshafts may be more complex, most engine manufacturers accept that added complexity as a trade-off for better engine performance. The fundamental reason for the OHC valvetrain is that it offers an increase in the ability to exchange induction. Another performance advantage is gained as a result of the better optimised port configurations made possible with overhead camshaft designs, with no intrusive pushrods, the overhead camshaft cylinder head design can use straighter ports of more advantageous cross-section and length. The OHC design allows for higher speeds than comparable cam-in-block designs. The higher engine speeds thus allowed increases power output for a given torque output, in earlier OHC systems, including inter-war Morrises and Wolseleys, oil leaks in the lubrication systems were an issue. Single overhead camshaft is a design in which one camshaft is placed within the cylinder head, in the SOHC design, the camshaft operates the valves directly, traditionally via a bucket tappet, or via an intermediary rocker arm. SOHC cylinder heads are less expensive to manufacture than double overhead camshaft cylinder heads.
Timing belt replacement can be easier since there are fewer camshaft drive sprockets that need to be aligned during the replacement procedure, SOHC designs offer reduced complexity compared to overhead valve designs — when used for multivalve cylinder heads, in which each cylinder has more than two valves. Exhaust and inlet manifolds were both on the side of the engine block. This did, offer excellent access to the spark plugs, in the early 1980s, Toyota and Volkswagen Group used a directly actuated, SOHC parallel valve configuration with two valves for each cylinder. The Toyota system used hydraulic tappets, the Volkswagen system used bucket tappets with shims for valve clearance adjustment. Honda used a similar system in their motorcycles, using the term Unicam for the concept. This system uses one camshaft for each bank of cylinder heads, with the cams operating directly onto the valve and indirectly, through a short rocker arm. This allows a compact, light valvetrain to operate valves in a combustion chamber.
The Unicam valve train was first used in single cylinder dirt bikes, a dual overhead camshaft valvetrain layout is characterised by two camshafts located within the cylinder head, one operating the intake valves and the other one operating the exhaust valves. This design reduces valvetrain inertia more than is the case with a SOHC engine, a DOHC design permits a wider angle between intake and exhaust valves than do SOHC engines. This can allow for a less restricted airflow at higher engine speeds, DOHC with a multivalve design allows for the optimum placement of the spark plug which, in turn, improves combustion efficiency
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders radiate outward from a central crankcase like the spokes of a wheel. It resembles a star when viewed from the front, and is called a star engine in some languages. The radial configuration was very commonly used for aircraft engines before gas turbine engines became predominant, the pistons are connected to the crankshaft with a master-and-articulating-rod assembly. One piston, the uppermost one in the animation, has a rod with a direct attachment to the crankshaft. The remaining pistons pin their connecting rods attachments to rings around the edge of the master rod, extra rows of radial cylinders can be added in order to increase the capacity of the engine without adding to its diameter. Four-stroke radials have an odd number of cylinders per row, so that a consistent every-other-piston firing order can be maintained, for example, on a five-cylinder engine the firing order is 1,3,5,2,4 and back to cylinder 1.
Moreover, this leaves a one-piston gap between the piston on its combustion stroke and the piston on compression. The active stroke directly helps compress the next cylinder to fire, if an even number of cylinders were used, an equally timed firing cycle would not be feasible. The radial engine normally uses fewer cam lobes than other types, as with most four-strokes, the crankshaft takes two revolutions to complete the four strokes of each piston. The camshaft ring is geared to spin slower and in the direction to the crankshaft. The cam lobes are placed in two rows for the intake and exhaust, for the example, four cam lobes serve all five cylinders, whereas 10 would be required for a typical inline engine with the same number of cylinders and valves. C. M. Manly constructed a water-cooled five-cylinder radial engine in 1901, manlys engine produced 52 hp at 950 rpm. This was installed in his triplane and made a number of short free-flight hops, another early radial engine was the three-cylinder Anzani, originally built as a W3 fan configuration, one of which powered Louis Blériots Blériot XI across the English Channel.
Georges Canton and Pierre Unné patented the engine design in 1909, offering it to the Salmson company. It was similar in concept to the radial, the main difference being that the propeller was bolted to the engine. The problem of the cooling of the cylinders, a factor with the early stationary radials, was alleviated by the engine generating its own cooling airflow. Most German aircraft of the time used water-cooled inline 6-cylinder engines, in the early 1920s Le Rhône converted a number of their rotary engines into stationary radial engines. By 1918 the potential advantages of air-cooled radials over the inline engine
Truck
A truck is a motor vehicle designed to transport cargo. Trucks vary greatly in size and configuration, smaller varieties may be similar to some automobiles. Commercial trucks can be large and powerful, and may be configured to mount specialized equipment, such as in the case of fire trucks and concrete mixers. Modern trucks are powered by diesel engines, although small to medium size trucks with gasoline engines exist in the US. In the European Union, vehicles with a gross mass of up to 3.5 t are known as light commercial vehicles. Trucks and cars have an ancestor, the steam-powered fardier Nicolas-Joseph Cugnot built in 1769. However, steam wagons were not common until the mid-1800s, the roads of the time, built for horse and carriages, limited these vehicles to very short hauls, usually from a factory to the nearest railway station. The first semi-trailer appeared in 1881, towed by a tractor manufactured by De Dion-Bouton. In 1895 Karl Benz designed and built the first truck in history using the internal combustion engine, that year some of Benzs trucks were modified to become the first bus by the Netphener, the first motorbus company in history.
A year later, in 1896, another internal combustion engine truck was built by Gottlieb Daimler, other companies, such as Peugeot, Renault and Büssing, built their own versions. The first truck in the United States was built by Autocar in 1899 and was available with optional 5 or 8 horsepower motors, trucks of the era mostly used two-cylinder engines and had a carrying capacity of 3,300 to 4,400 lb. In 1904,700 heavy trucks were built in the United States,1000 in 1907,6000 in 1910, after World War I, several advances were made, pneumatic tires replaced the previously common full rubber versions. Electric starters, power brakes,4,6, and 8 cylinder engines, closed cabs, the first modern semi-trailer trucks appeared. Touring car builders such as Ford and Renault entered the heavy truck market, although it had been invented in 1890, the diesel engine was not common in trucks in Europe until the 1930s. In the United States, it took longer for diesel engines to be accepted. The word truck might come from a back-formation of truckle, meaning small wheel or pulley, from Middle English trokell, another possible source is the Latin trochus, meaning iron hoop.
In turn, both sources emanate from the Greek trokhos, meaning wheel, from trekhein, the first known usage of truck was in 1611, when it referred to the small strong wheels on ships cannon carriages. In its extended usage it came to refer to carts for carrying heavy loads and its expanded application to motor-powered load carrier has been in usage since 1930, shortened from motor truck, which dates back to 1901
Volkswagen Group
Volkswagen Group, or Volkswagen Aktiengesellschaft, shortly VW AG, is a German multinational automotive manufacturing company headquartered in Wolfsburg, Lower Saxony, Germany. It designs and distributes passenger and commercial vehicles, engines, in 2016, it was the largest automaker in the world with sales of 10.3 million units, overtaking Toyota. It has maintained the largest market share in Europe for over two decades and it ranked seventh in the 2016 Fortune Global 500 list of the worlds largest companies. It is divided into two divisions, the Automotive Division and the Financial Services Division, and has approximately 340 subsidiary companies. VW has two major joint-ventures in China, the company has operations in approximately 150 countries and operates 100 production facilities across 27 countries. Volkswagen was founded in 1937 to manufacture the car which would become known as the Beetle, the companys production grew rapidly in the 1950s and 1960s, and in 1965 it acquired Auto Union, which subsequently produced the first post-war Audi models.
Volkswagen launched a new generation of front-wheel drive vehicles in the 1970s, including the Passat and Golf, the companys operations in China have grown rapidly in the past decade with the country becoming its largest market. It has been traded in the United States via American depositary receipts since 1988, Volkswagen delisted from the London Stock Exchange in 2013. The state of Lower Saxony holds 12. 7% of the companys shares, Volkswagen held a 19. 9% non-controlling shareholding in Suzuki between 2009 and 2015. An international arbitration court ordered Volkswagen to sell the back to Suzuki. Suzuki paid $3. 8bn to complete the stock buy-back just hours prior to a scandal about emissions violations engulfing Volkswagen. Volkswagen was founded on 28 May 1937 in Berlin as the Gesellschaft zur Vorbereitung des Deutschen Volkswagens mbH by the National Socialist Deutsche Arbeitsfront. The purpose of the company was to manufacture the Volkswagen car, originally referred to as the Porsche Type 60, the Volkswagen Type 1 and this vehicle was designed by Ferdinand Porsches consulting firm, and the company was backed by the support of Adolf Hitler.
On 16 September 1938, Gezuvor was renamed Volkswagenwerk GmbH, only a small number of Type 60 Volkswagens were made during this time. The Fallersleben plant manufactured the V-1 flying bomb, making the plant a major bombing target for the Allied forces, however, no British car manufacturer was interested, the vehicle does not meet the fundamental technical requirement of a motor-car. It is quite unattractive to the average buyer, to build the car commercially would be a completely uneconomic enterprise. In 1948, the Ford Motor Company of USA was offered Volkswagen, but Ernest Breech, as part of the Industrial plans for Germany, large parts of German industry, including Volkswagen, were to be dismantled. Total German car production was set at a maximum of 10% of the 1936 car production numbers
Harry Ricardo
Sir Harry Ralph Ricardo was one of the foremost engine designers and researchers in the early years of the development of the internal combustion engine. Ricardo was descended from a brother of the political economist David Ricardo. He was one of the first people in England to see an automobile when his grandfather purchased one in 1898 and he was from a relatively wealthy family and educated at Rugby School. In October 1903 he joined Trinity College, Cambridge as an engineering student. Ricardo had been using tools and building engines since the age of ten, in 1911 Ricardo married Beatrice Bertha Hale, an art student at the Slade School of Art, in London. Her father, Charles Bowdich Hale, was the Ricardos family doctor and they had three daughters, and lived most of their married life at Lancing and Edburton in West Sussex. His engine had a cylinder, and was the heaviest entered. He was persuaded to join the Professor of Mechanism and Applied Mechanics, Bertram Hopkinson and he graduated with a degree in 1906 and spent another year researching at Cambridge.
Ricardo is said by Percy Kidner, Co-managing director of Vauxhall, before graduation, Ricardo had designed a two-stroke motorcycle engine to study the effect of mixture strength upon the combustion process. When he graduated, the firm of Messrs Lloyd and Plaister expressed interest in making the engine. Ricardo produced designs for two sizes, and the one sold about 50 engines until 1914, when the war halted production. In 1909 he designed a two-stroke 3. 3-litre engine, for his cousin Ralph Ricardo, the engine was to be used in the Dolphin car. The cars were made, but it became apparent that they cost more to make than the selling price. The company fared better making two-stroke engines for fishing boats, in 1911 the firm collapsed and Ralph departed for India. Ricardo continued to design engines for electric lighting sets, these were produced by two companies until 1914. In 1915 Ricardo set up a new company, Engine Patents Ltd. which developed the engine that would eventually be used in the first successful tank design, the Daimler sleeve-valve engine used in the Mark I created copious amounts of smoke, which easily gave away its position.
Ricardo was asked to look at the problem of reducing smoky exhaust gases, existing companies were able to undertake construction of such an engine but not the design, so Ricardo designed it himself. As well as having reduced emissions, the new engine was much more powerful than the existing ones
V engine
A V engine, or Vee engine is a common configuration for an internal combustion engine. The cylinders and pistons are aligned, in two planes or banks, so that they appear to be in a V when viewed along the axis of the crankshaft. The Vee configuration generally reduces the engine length and weight compared to an equivalent inline configuration. The first V-type engine, a 2-cylinder vee twin, was built in 1889 by Daimler, by 1903 V8 engines were being produced for motor boat racing by the Société Antoinette to designs by Léon Levavasseur, building on experience gained with in-line four-cylinder engines. In 1904, the Putney Motor Works completed a new V12 marine racing engine – the first V12 engine produced for any purpose. Usually, each pair of corresponding pistons from each bank of cylinders share one crankpin on the crankshaft, some V-twin engine designs have two-pin cranks, while other V configurations include split crank-pins for more even firing. V-engines are generally more compact than straight engines with cylinders of the same dimensions, various cylinder bank angles of Vee are used in different engines, depending on the number of cylinders, there may be angles that work better than others for stability.
Some Vee configurations are well-balanced and smooth, while others are less smoothly running than their equivalent straight counterparts, v8s with crossplane crankshaft can be easily balanced with the use of counterweights only. V12s, being in effect two straight-6 engines married together, are balanced, if the V-angle is 60° for 4-stroke or 30° for 2-stroke. Others, such as the V2, V4, V6, flatplane V8, V10, V14 and V18 engine show increased vibration, certain types of Vee engine have been built as inverted engines, most commonly for aircraft. Advantages include better visibility in an airplane, and lower centre of gravity. Examples include World War II German Daimler-Benz DB601, Junkers Jumo, and Argus Motoren piston engines
Locomotive
A locomotive or engine is a rail transport vehicle that provides the motive power for a train. A locomotive has no payload capacity of its own, and its purpose is to move the train along the tracks. In contrast, some trains have self-propelled payload-carrying vehicles and these are not normally considered locomotives, and may be referred to as multiple units, motor coaches or railcars. The use of these vehicles is increasingly common for passenger trains. Traditionally, locomotives pulled trains from the front, push-pull operation has become common, where the train may have a locomotive at the front, at the rear, or at each end. Prior to locomotives, the force for railroads had been generated by various lower-technology methods such as human power, horse power. The first successful locomotives were built by Cornish inventor Richard Trevithick, in 1804 his unnamed steam locomotive hauled a train along the tramway of the Penydarren ironworks, near Merthyr Tydfil in Wales. Although the locomotive hauled a train of 10 long tons of iron and 70 passengers in five wagons over nine miles, the locomotive only ran three trips before it was abandoned.
Trevithick built a series of locomotives after the Penydarren experiment, including one which ran at a colliery in Tyneside in northern England, the first commercially successful steam locomotive was Matthew Murrays rack locomotive, built for the narrow gauge Middleton Railway in 1812. This was followed in 1813 by the Puffing Billy built by Christopher Blackett and William Hedley for the Wylam Colliery Railway, Puffing Billy is now on display in the Science Museum in London, the oldest locomotive in existence. In 1814 George Stephenson, inspired by the locomotives of Trevithick. He built the Blücher, one of the first successful flanged-wheel adhesion locomotives, Stephenson played a pivotal role in the development and widespread adoption of steam locomotives. His designs improved on the work of the pioneers, in 1825 he built the Locomotion for the Stockton and Darlington Railway, north east England, which became the first public steam railway. In 1829 he built The Rocket which was entered in and won the Rainhill Trials and this success led to Stephenson establishing his company as the pre-eminent builder of steam locomotives used on railways in the United Kingdom, the United States and much of Europe.
The first inter city passenger railway and Manchester Railway, opened in 1830, there are a few basic reasons to isolate locomotive train power, as compared to self-propelled vehicles. Maximum utilization of power cars Separate locomotives facilitate movement of costly motive power assets as needed, flexibility Large locomotives can substitute for small locomotives when more power is required, for example, where grades are steeper. As needed, a locomotive can be used for freight duties. Obsolescence cycles Separating motive power from payload-hauling cars enables replacement without affecting the other, to illustrate, locomotives might become obsolete when their associated cars did not, and vice versa
Cylinder head porting
Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow. Cylinder heads, as manufactured, are usually due to design. Porting the heads provides the finely detailed attention required to bring the engine to the highest level of efficiency, more than any other single factor, the porting process is responsible for the high power output of modern engines. Daily human experience with air gives the impression that air is light, however, an engine running at high speed experiences a totally different substance. In that context, air can be thought of as thick, elastic, pumping it is a major problem for engines running at speed, so head porting helps to alleviate this. For major modifications the ports must be welded up or similarly built up to add material where none existed, the Ford two-liter shown above in stock trim was capable of delivering 115 horsepower@5500 rpm for a BMEP of 136 psi.
Contrast this with the Pro Stock ports shown below and this aftermarket racing GM Pro Stock head was capable of 1300 horsepower@9500 rpm with a BMEP of 238 psi. Since BMEP is an excellent efficiency measure and closely related to volumetric efficiency, in fact a BMEP of 238 puts it near the top of the racing engine world. It is close to the limit for a naturally aspirated gas-burning engine, formula 1 four-valve/cylinder engines typically achieve BMEP values of 220 psi. Of course cam profiles, engine rpm, engine height constraints and other limitations play a role in this difference as well, when the valve opens, the air doesn’t flow in, it decompresses into the low-pressure region below it. All the air on the side of the moving disturbance boundary is completely isolated and unaffected by what happens on the downstream side. The air at the entrance does not move until the wave reaches all the way to the end. It is only that the runner can begin to flow. Up until that point all that can happen is the higher pressure gas filling the volume of the runner decompresses or expands into the low-pressure region advancing up the runner.
Conversely, the closing of the valve does not immediately stop flow at the runner entrance, the closing valve causes a buildup of pressure that travels up the runner as a positive wave. The runner entrance continues to flow at full speed, forcing the pressure to rise until the signal reaches the entrance and this very considerable pressure rise can be seen on the graph below, it rises far above atmospheric pressure. It is this phenomenon that enables the so-called “ram tuning” to occur, the principle is the same as in the water hammer effect so well known to plumbers. The speed that the signal can travel is the speed of sound within the runner and this is why port/runner volumes are so important, the volumes of successive parts of the port/runner control the flow during all transition periods
Flathead engine
A flathead engine is an internal combustion engine with valves placed in the engine block beside the piston, instead of in the cylinder head, as in an overhead valve engine. As the cylinder cross-section has the shape of an upside-down L, the sidevalves poppet valves are usually sited on one side of the cylinder. A recess in the head creates a corridor connecting the valves. The valve gear comprises a camshaft which operates the valves via simple tappets, however, employs both rocker arms and pushrods to transmiit motion from the cam lobes to the valve stems. Flathead designs are commonly built new for many small engine applications of one. The main advantages of an engine are simplicity, low cost, responsive low-speed power, low mechanical engine noise. The absence of an overhead valve valvetrain allows a compact engine that is less expensive to manufacture. Even today, flatheads are common in lawnmowers and basic farm machinery, if a valve head breaks off, it may become lodged between the piston and the head causing severe damage.
At top dead centre, the piston gets very close to the portion of the cylinder head above. The typical flathead engine has its valves adjacent, but the T-head variant acts as a cross-flow head, the main disadvantages of a sidevalve engine are poor gas flow, poor combustion chamber shape, and low compression ratio, all of which result in a low power output. The sidevalve configuration makes intake and exhaust gases follow a route, with low volumetric efficiency. Although a sidevalve engine can operate at high speed, its volumetric efficiency swiftly deteriorates. High volumetric efficiency was important for early cars because their engines rarely sustained extended high speeds. A compromise used by Willys and Rolls-Royce in the 1950s was the F-head, in there is one side valve. An advance in technology resulted from experimentation in the 1920s by Sir Harry Ricardo. Because the exhaust follows a path to leave the engine. In a T-head engine, the pairs have a crossflow configuration. American LaFrance powered their fire engines with T-head engines from the 1920s to the 1950s, the Cleveland Motorcycle Manufacturing Company produced a T-head four-cylinder in-line motorcycle engine in the 1920s, and early Stutz engines were T heads
