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, 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; when the piston has moved up to the top of its stroke inside the cylinder, the remaining volume inside the head or combustion chamber has been reduced to 100 cc 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, 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, therefore the energy wasted to the atmosphere. Diesel engines 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 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. 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 lead to engine knock.
Static compression ratio is calculated by the formula C R = V d + V c V c Where: V d = displacement volume. This is the volume inside the cylinder displaced by the piston from the beginning of the compression stroke to the end of the stroke. V c = clearance volume; this is the volume of the space in the cylinder left at the end of the compression stroke. V d can be estimated by the cylinder volume formula V d = π 4 b 2 s Where: b = cylinder bore s = piston stroke lengthBecause of the complex shape of V c it is measured directly; this is done by filling the cylinder with liquid and measuring the volume of the used liquid. The compression ratio in a gasoline -powered engine will not be much higher than 10:1 due to potential engine knocking and not lower than 6:1; some production automotive engines built for high performance from 1955–1972, used high-octane leaded gasoline or'5 star' to allow compression ratios as high as 13.0:1. A technique used to prevent the onset of knock is the high "swirl" engine that forces the intake charge to adopt a fast circular rotation in the cylinder during compression that provides quicker and more complete combustion.
It is possible to manufacture gasoline engines with compression ratios of over 11:1 that can use 87 /2 fuel with the addition of variable valve timing and knock sensors to delay ignition timing. Such engines may not produce their full rated power using 87 octane gasoline under all circumstances, due to the delayed ignition timing. Direct fuel injection, which can inject fuel only at the time of fuel ignition, is another recent development which allows for higher compression ratios on gasoline engines; the compression ratio can be as high as 14:1 in engines with a'ping' or'knock' sensor and an electronic control unit. In 1981, Jaguar released a cylinder head; the cylinder head design was known as the "May Fireball" head. In 2012, Mazda released new petrol engines under the brand name SkyActiv with a 14:1 compression ratio, to be used in all Mazda vehicles by 2015; the SkyActiv engine achieves this compression ratio with ordinary unleaded gasoline through improved scavenging of exhaust gases, in addition to direct injection.
In a turbocharged or supercharged gasoline engine, the CR is customarily built at 10.5:1 or lower. This is due to the turbocharger/supercharger having compressed the air before it enters the cylinders. Port fuel injected engines run lower boost than direct fuel injected engines because port fuel inj
A centrifugal clutch is a clutch that uses centrifugal force to connect two concentric shafts, with the driving shaft nested inside the driven shaft. It engages more at higher speeds; the input of the clutch is connected to the engine crankshaft while the output may drive a shaft, chain, or belt. As engine revolutions per minute increase, weighted arms in the clutch swing outward and force the clutch to engage; the most common types have friction pads or shoes radially mounted that engage the inside of the rim of a housing. On the center shaft there are an assorted number of extension springs, which connect to a clutch shoe; when the central shaft spins fast enough, the springs extend causing the clutch shoes to engage the friction face. It can be compared to a drum brake in reverse; this type can be found on most home built karts and garden equipment, fuel-powered model cars and low power chainsaws. Another type used in racing karts has friction and clutch disks stacked together like a motorcycle clutch.
The weighted arms engage the clutch. When the engine reaches a certain speed, the clutch activates, working somewhat like a continuously variable transmission; as the load increases, the speed drops, disengaging the clutch, letting the speed rise again and reengaging the clutch. If tuned properly, the clutch will tend to keep the speed near the torque peak of the engine; this results in a fair bit of waste heat, but over a broad range of speeds it is much more useful than a direct drive in many applications. Centrifugal clutches are used in mopeds, lawn mowers, go-karts, mini bikes, some paramotors and boats to: keep the internal combustion engine from stalling when the output shaft is slowed or stopped abruptly disengage loads when starting and idling. Thomas Fogarty, credited with inventing the balloon catheter, is credited with inventing a centrifugal clutch in the 1940s although automobiles were being manufactured with centrifugal clutches as early as 1936. There is a design for an'automatic clutch' in the'Meccano Magazine' of June 1931.
But centrifugal clutches were used in railway locomotives much earlier, referred to in a patent of 1899. A device such as this was used in the Taylor Aerocar roadable airplane of the late 1940s and early 1950s. Saxomat Fluid coupling Compliant Centrifugal Clutches: Design and Testing, Master's thesis at the Harold B. Lee Library, Brigham Young University
Honda Motor Company, Ltd. is a Japanese public multinational conglomerate corporation known as a manufacturer of automobiles, aircraft and power equipment. Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than 14 million internal combustion engines each year. Honda became the second-largest Japanese automobile manufacturer in 2001. Honda was the eighth largest automobile manufacturer in the world in 2015. Honda was the first Japanese automobile manufacturer to release a dedicated luxury brand, Acura, in 1986. Aside from their core automobile and motorcycle businesses, Honda manufactures garden equipment, marine engines, personal watercraft and power generators, other products. Since 1986, Honda has been involved with artificial intelligence/robotics research and released their ASIMO robot in 2000, 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 development. In 2013, Honda became the first Japanese automaker to be a net exporter from the United States, exporting 108,705 Honda and Acura models, while importing only 88,357. Throughout his life, Honda's founder, Soichiro Honda, had an interest in automobiles, he worked as a mechanic at the Art Shokai garage, where he entered them in races. 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, but lost the contract due to the poor quality of their products. After attending engineering school without graduating, visiting factories around Japan to better understand Toyota's quality control processes, by 1941 Honda was able to mass-produce piston rings acceptable to Toyota, using an automated process that could employ unskilled wartime laborers.
Tōkai Seiki was placed under control of the Ministry of Commerce and Industry at the start of World War II, Soichiro Honda was demoted from president to senior managing director after Toyota took a 40% stake in the company. 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 and the Imperial Japanese Navy would be instrumental in the postwar period. A US B-29 bomber attack destroyed Tōkai Seiki's Yamashita plant in 1944, the Itawa plant collapsed in 13 January 1945 Mikawa earthquake. Soichiro Honda sold the salvageable remains of the company to Toyota after the war for ¥450,000, used the proceeds to found the Honda Technical Research Institute in October 1946. 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, supplying these to customers to attach to their bicycles. This was the Honda A-Type, nicknamed the Bata Bata for the sound. 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, Takeo Fujisawa who provided indispensable business and marketing expertise to complement Soichiro Honda's 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 short time to become the world's largest manufacturer of motorcycles by 1964; the first production automobile from Honda was the T360 mini pick-up truck, which went on sale in August 1963. 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, which followed the T360 into production in October 1963. Its chain-driven rear wheels pointed to Honda's motorcycle origins. Over the next few decades, Honda worked to expand its product line and expanded operations and exports to numerous countries around the world. In 1986, Honda introduced the successful Acura brand to the American market in an attempt to gain ground in the luxury vehicle market; the year 1991 saw the introduction of the Honda NSX supercar, the first all-aluminum monocoque vehicle that incorporated a mid-engine V6 with variable-valve timing. CEO Tadashi Kume was succeeded by Nobuhiko Kawamoto in 1990. Kawamoto was selected over Shoichiro Irimajiri, who oversaw the successful establishment of Honda of America Manufacturing, Inc. in Marysville, Ohio. Irimajiri and Kawamoto shared a friendly rivalry within Honda. Following the death of Soichiro Honda and the departure of Irimajiri, Honda found itself being outpaced in product development by other Japanese automakers and was caught off-guard by the truck and sport utility vehicle boom of the 1990s, all which took a toll on the profitability of the company.
Japanese media reported in 1992 and 1993 that Honda was at serious risk of an unwanted and hostile takeov
A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage. Gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next; the transmission of rotation between contacting toothed wheels can be traced back to the Antikythera mechanism of Greece and the south-pointing chariot of China. Illustrations by the Renaissance scientist Georgius Agricola show gear trains with cylindrical teeth; the implementation of the involute tooth yielded a standard gear design that provides a constant speed ratio. Features of gears and gear trains include: The ratio of the pitch circles of mating gears defines the speed ratio and the mechanical advantage of the gear set. A planetary gear train provides high gear reduction in a compact package, it is possible to design gear teeth for gears that are non-circular, yet still transmit torque smoothly. The speed ratios of chain and belt drives are computed in the same way as gear ratios.
See bicycle gearing. Gear teeth are designed so the number of teeth on a gear is proportional to the radius of its pitch circle, so the pitch circles of meshing gears roll on each other without slipping; the speed ratio for a pair of meshing gears can be computed from ratio of the radii of the pitch circles and the ratio of the number of teeth on each gear. The velocity v of the point of contact on the pitch circles is the same on both gears, is given by v = r A ω A = r B ω B, where input gear A with radius rA and angular velocity ωA meshes with output gear B with radius rB and angular velocity ωB. Therefore, ω A ω B = r B r A = N B N A. where NA is the number of teeth on the input gear and NB is the number of teeth on the output gear. The mechanical advantage of a pair of meshing gears for which the input gear has NA teeth and the output gear has NB teeth is given by M A = N B N A; this shows that if the output gear GB has more teeth than the input gear GA the gear train amplifies the input torque.
And, if the output gear has fewer teeth than the input gear the gear train reduces the input torque. If the output gear of a gear train rotates more than the input gear the gear train is called a speed reducer. In this case, because the output gear must have more teeth than the input gear, the speed reducer amplifies the input torque. For this analysis, we consider a gear train that has one degree-of-freedom, which means the angular rotation of all the gears in the gear train are defined by the angle of the input gear; the size of the gears and the sequence in which they engage define the ratio of the angular velocity ωA of the input gear to the angular velocity ωB of the output gear, known as the speed ratio, or gear ratio, of the gear train. Let R be the speed ratio ω A ω B = R; the input torque TA acting on the input gear GA is transformed by the gear train into the output torque TB exerted by the output gear GB. If we assume the gears are rigid and there are no losses in the engagement of the gear teeth the principle of virtual work can be used to analyze the static equilibrium of the gear train.
Let the angle θ of the input gear be the generalized coordinate of the gear train the speed ratio R of the gear train defines the angular velocity of the output gear in terms of the input gear: ω A = ω, ω B = ω / R. The formula for the generalized force obtained from the principle of virtual work with applied torques yields: F θ = T A ∂ ω A ∂ ω − T B ∂ ω B ∂ ω = T A − T B / R = 0; the mechanical advantage of the gear train is the ratio of the output torque TB to the input torque TA, the above equation yields: M A = T B T A = R. The speed ratio of a gear train defines its mechanical advantage; this shows that if the input gear rotates faster than the output gear the gear train amplifies the input torque. And if the input gear rotates slower than the output gear, the gear train reduces the input torque; the simplest example of a gear train has two gears. The "input gear" transmits power to the "output gear"; the input gear will be connected to a power source, such as a motor or engine. In such a
A contact breaker is a type of electrical switch, the term refers to the switching device found in the distributor of the ignition systems of spark-ignition internal combustion engines. The purpose of the contact breaker is to interrupt the current flowing in the primary winding of the ignition coil; when this occurs, the collapsing current induces a high voltage in the secondary winding of the coil, which has many more windings. This causes a high voltage to appear at the coil output for a short period—enough to arc across the electrodes of a spark plug; the contact breaker is operated by an engine-driven cam, the position of the contact breaker is set so that it opens at the correct moment needed to ignite the fuel at the top of the piston's compression stroke. The contact breaker is mounted on a plate, able to rotate relative to the camshaft operating it; the plate is rotated by a centrifugal mechanism, thus advancing the ignition timing at higher revolutions. This gives the fuel time to burn so that the resulting gases reach their maximum pressure at the same time as the piston reaches the top of the cylinder.
The plate's position can be moved a small distance using a small manifold vacuum-operated servomechanism, providing advanced timing when the engine is required to speed up on demand. This helps to prevent pre-ignition. Since they open and close several times with every turn of the engine, contact breaker points and cam follower suffer from wear—both mechanical and pitting caused by arcing across the contacts; this latter effect is prevented by placing a capacitor parallel across the contact breaker—this is referred to by the more old fashioned term condenser by mechanics. As well as suppressing arcing, it helps boost the coil output by creating a resonant LC circuit with the coil windings. A drawback of using a mechanical switch as part of the ignition timing is that it is not precise, needs regular adjustment of the dwell angle, at higher revolutions, its mass becomes significant, leading to poor operation at higher engine speeds; these effects can be overcome using electronic ignition systems, where the contact breakers are retrofitted by a magnetic or optical sensor device.
However, because of their simplicity, since contact breaker points degrade instead of catastrophically failing, they are still used on aircraft engines. Ignition magneto
Honda CT series
The Honda CT series was a group of Honda trail bike motorcycles made since 1964. The CT designation is a slight exception in Honda nomenclature in that "CT" does not indicate a series of mechanically related bikes, but rather a group of different bikes that are all for casual off-road use. A description of the CT-series is convoluted because it spans several decades during which Honda altered its naming system, re-used issued CT designations, assigned different model names for different markets, sometimes used multiple names for the same model within single markets; the CT designation has been used for the Trail Cub series of bikes since 1964. Alongside, a ST-series bike was renamed CT70 for the Canadian and US market from 1969 to 1994. Honda uses the CT designation to cover an Australia-only series of "farm bikes" for agricultural work. In 1981 Honda released a CT250S Silk Road "trekking bike", in 1983 a Japan-only CT50 Motra minibike; these last two vehicles are mechanically unrelated to other CT-series bikes, each other.
The Trail Cub series is an offshoot of the popular Super Cub line, the bikes are known by several names. In Japan they were introduced as the Hunter Cub, while in the Canada/US market they were called the Trail Cub or just "Trail" followed by a number indicating engine size, such as "Trail 90". Individual models may be known by model number, such as CT90 and CT110. In Australia the CT110 has acquired the popular moniker "Postie Bike" due to its long association with the Australia Post; these small 17" wheel bikes are intended for slow off-road travel. They have 4-stroke engines ranging from 49 cc to 105 cc, automatic clutches. All bikes have either 3- or 4-speed transmissions, plus a second choice of HIGH or LOW bands to apply the same gears to road travel or slower off-road travel; the early bikes achieved this by having two drive sprockets at the rear wheel, which required the rider to dismount and thread the chain onto the desired sprocket. Bikes placed the two-stage choice within the gearbox, required the rider to only move a lever.
The initial model numbers are T for Trail. These bikes are technically not C - and CA - series variants. However, Honda would give the new Trail Cub line its own CT designation by 1964, so any overview of the CT-series should include these first models for clarity. There is no CA100H because CA100 designated an America-only export Super Cub, hence H for Hunter version would not apply; these first bikes exhibit the chief characteristics of the Trail Cub line. The Super Cub's plastic engine cover and leg shield were removed, exposing the long single tube joining the rear pressed-steel frame with the forks; the bikes have knobby tires, the Super Cub's large front fender was replaced with a smaller unit to better clear mud. The Trail Cub has a single saddle followed by a large chrome equipment rack, on which a second saddle can be installed. There is a skid plate to prevent damage to the low-slung engine; as with all Cubs, the fuel tank is within the seat pedestal. These bikes introduce characteristics that would only be typical of the first few Trail Cub models.
The forks are Super Cub style. The long exhaust pipe sweeps straight back horizontal near the ground, unlike the upswept exhaust that would become characteristic of bikes; the stepped chainrings are quite evident, as the larger off-road ring is nearly twice the diameter of the road ring. This large sprocket required the left rear shock absorber to be repositioned outboard of the swingarm, on an extended top mount, the right side remaining in its normal C100 position inboard of the swingarm; the "105" bikes are identical to their "100" predecessor. The rear shock mounts are made further apart to place both outboard of the swingarm. There is a slight increase in engine size from 49 cc to 54 cc, 1963 sees the introduction the distinctive upswept exhaust with large chrome heat-shield; the 1964 CT200 is technically the first "CT-series" Honda. This bike represents a large increase in engine size from 54 cc to 87 cc, the introduction of a 4-speed transmission; this bike introduced adjustable steel-tube handlebars, rather than the fixed, pressed-steel covered, Super Cub style bars of previous bikes.
It was a bigger heavier bike, the frame and engine being based on the CM90, rather than the C100.- The CT90 begins the now-familiar Honda nomenclature of prefix letters indicating bike family, followed by numbers indicating engine size. The 87cc OHV engine is replaced by an 89cc alloy-head OHC unit, a 4-speed version of that used in the CM91 Super Cub; this model sees two important improvements to the series. In 1968 the stepped-chainring is replaced with a convenient secondary gearbox that only requires a turn of a small lever placed near the rider's left heel. In 1969 the Super Cub style leading-link fork is replaced with a modern telescopic fork of increased travel; this Trail Cub would become one of the most popular models. In 1968 Honda announced a new CT50 Hunter Cub for the home market; this light-weight bike featured the new dual-range gearbox, coupled with a 3-speed transmission. It retained the Super Cub style leading-link fork; the CT110 is the final model of the Trail Cub line. It is identical to the CT90 except for an increase in engine size from 89.5 cc to 105 cc.
Late model CT110 have a enclosed chainguard like a Super Cub. The bike was last sold in the US in 1986. Honda lists domestic production from 1981 to 2000; the CT110 has a long association with
In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels. For road vehicles with more than two axles, the wheelbase is the distance between the steering axle and the centerpoint of the driving axle group. In the case of a tri-axle truck, the wheelbase would be the distance between the steering axle and a point midway between the two rear axles; the wheelbase of a vehicle equals the distance between its rear wheels. At equilibrium, the total torque of the forces acting on a vehicle is zero. Therefore, the wheelbase is related to the force on each pair of tires by the following formula: F f = d r L m g F r = d f L m g where F f is the force on the front tires, F r is the force on the rear tires, L is the wheelbase, d r is the distance from the center of mass to the rear wheels, d f is the distance from the center of gravity to the front wheels, m is the mass of the vehicle, g is the gravity constant. So, for example, when a truck is loaded, its center of gravity shifts rearward and the force on the rear tires increases.
The vehicle will ride lower. The amount the vehicle sinks will depend on counter acting forces, like the size of the tires, tire pressure, the spring rate of the suspension. If the vehicle is accelerating or decelerating, extra torque is placed on the rear or front tire respectively; the equation relating the wheelbase, height above the ground of the CM, the force on each pair of tires becomes: F f = d r L m g − h c m L m a F r = d f L m g + h c m L m a where F f is the force on the front tires, F r is the force on the rear tires, d r is the distance from the CM to the rear wheels, d f is the distance from the CM to the front wheels, L is the wheelbase, m is the mass of the vehicle, g is the acceleration of gravity, h c m is the height of the CM above the ground, a is the acceleration. So, as is common experience, when the vehicle accelerates, the rear sinks and the front rises depending on the suspension; when braking the front noses down and the rear rises.:Because of the effect the wheelbase has on the weight distribution of the vehicle, wheelbase dimensions are crucial to the balance and steering.
For example, a car with a much greater weight load on the rear tends to understeer due to the lack of the load on the front tires and therefore the grip from them. This is why it is crucial, when towing a single-axle caravan, to distribute the caravan's weight so that down-thrust on the tow-hook is about 100 pounds force. A car may oversteer or "spin out" if there is too much force on the front tires and not enough on the rear tires; when turning there is lateral torque placed upon the tires which imparts a turning force that depends upon the length of the tire distances from the CM. Thus, in a car with a short wheelbase, the short lever arm from the CM to the rear wheel will result in a greater lateral force on the rear tire which means greater acceleration and less time for the driver to adjust and prevent a spin out or worse. Wheelbases provide the basis for one of the most common vehicle size class systems; some luxury vehicles are offered with long-wheelbase variants to increase the spaciousness and therefore the luxury of the vehicle.
This practice can be found on full-size cars like the Mercedes-Benz S-Class, but ultra-luxury vehicles such as the Rolls-Royce Phantom and large family cars like the Rover 75 came with'limousine' versions. Prime Minister of the United Kingdom Tony Blair was given a long-wheelbase version of the Rover 75 for official use, and some SUVs like the VW Tiguan and Jeep Wrangler come in LWB models In contrast, coupé varieties of some vehicles such as the Honda Accord are built on shorter wheelbases than the sedans they are derived from. The wheelbase on many commercially available bicycles and motorcycles is so short, relative to the height of their centers of mass, that they are able to perform stoppies and wheelies. In skateboarding the word'wheelbase' is used for the distance between the two inner pairs of mounting holes on the deck; this is different from the distance between the rotational centers