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65-537: A straight-eight can be timed for inherent primary and secondary balance , with no unbalanced primary or secondary forces or moments. However, crankshaft torsional vibration , present to some degree in all engines, is sufficient to require the use of a harmonic damper at the accessory end of the crankshaft. Without such damping, fatigue cracking near the rear main bearing journal may occur, leading to engine failure. Although an inline six -cylinder engine can also be timed for inherent primary and secondary balance,

130-520: A 'boxer' engine. A 180-degree V engine as used in the Ferrari 512BB has opposed cylinder pairs whose connecting rods use the same crank throw. Contrary to this, in a 'boxer' engine, as applied in BMW motorcycles, each connecting rod has its own crank throw which is positioned 180 degrees from the crank throw of the opposed cylinder.] Flat-twin engines typically use 180° crankshafts and separate crank throws and have

195-425: A (4.0" bore × 3 13 ⁄ 64 " stroke = 322 in³ (5.277 L)) V8 in 1953, with similar displacement as their (3 7 ⁄ 16 " bore × 4 5 ⁄ 16 " stroke = 320.2 in³ (5.247 L)) straight-8, the latter being produced until the end of the 1953 model year. Pontiac maintained production on their straight-eight, as well as a L-head inline six, through the end of the 1954 model year, after which

260-408: A 4-cylinder inline engine would have perfect balance, a net secondary imbalance remains. This is because the big end of the connecting rod swings from side to side, so that the motion of the small end deviates from ideal sinusoidal motion between top and bottom dead centre on each swing, i.e. twice per crank revolution, and the distance the small end (and a piston connected to it) has to travel in

325-417: A 4–8–2 the effects of 26,000 lb dynamic augment under the cg did not show up in the cab but the same augment in any other axle would have. Balance weights are installed opposite the parts causing the out-of-balance. The only available plane for these weights is in the wheel itself which results in an out-of-balance couple on the wheel/axle assembly. The wheel is statically balanced only. A proportion of

390-522: A V8 became standard. Packard ended production of their signature straight-eight at the end of 1954, replacing it with an overhead valve V8. By the end of the 1970s overhead valve V8s powered 80% of automobiles built in the US, and most of the rest had six-cylinder engines. In Europe, many automobile factories had been destroyed during World War II, and it took many years before war-devastated economies recovered enough to make large cars popular again. The change in

455-404: A damper. Vibration occurs around the axis of a crankshaft, since the connecting rods are usually located at different distances from the resistive torque (e.g. the clutch). This vibration is not transferred to outside of the engine, however fatigue from the vibration could cause crankshaft failure. Radial engines do not experience torsional imbalance. Primary imbalance produces vibration at

520-444: A flywheel with an uneven weight distribution can cause a rotating unbalance . Even with a perfectly balanced weight distribution of the static masses, some cylinder layouts cause imbalance due to the forces from each cylinder not cancelling each other out at all times. For example, an inline-four engine has a vertical vibration (at twice the engine speed). These imbalances are inherent in the design and unable to be avoided, therefore

585-445: A locomotive are briefly shown by describing measurements of locomotive motions as well as deflections in steel bridges. These measurements show the need for various balancing methods as well as other design features to reduce vibration amplitudes and damage to the locomotive itself as well as to the rails and bridges. The example locomotive is a simple, non-compound, type with two outside cylinders and valve gear, coupled driving wheels and

650-421: A road trip in terms of the riding qualities in the cab. They may not be a reliable indicator of a requirement for better balance as unrelated factors may cause rough riding, such as stuck wedges, fouled equalizers and slack between the engine and tender. Also the position of an out-of-balance axle relative to the locomotive centre of gravity may determine the extent of motion at the cab. A. H. Fetters related that on

715-471: A separate tender. Only basic balancing is covered with no mention of the effects of different cylinder arrangements, crank angles, etc. since balancing methods for three- and four-cylinder locomotives can be complicated and diverse. Mathematical treatments can be found in 'further reading'. For example, Dalby's "The Balancing of Engines" covers the treatment of unbalanced forces and couples using polygons. Johnson and Fry both use algebraic calculations. At speed

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780-461: A six-year gap in the middle caused by the war). By 1951, their 1.5 L supercharged engines could produce 425 bhp (317 kW) at 9,300 rpm, and could rev as high as 10,500 rpm. However, the engines were at the end of their potential, and rule changes for the 1952 season made the Alfettas obsolete. Mercedes-Benz would create the last notable straight-eight racing cars in 1955, with

845-422: A straight-eight develops more power strokes per revolution and, as a result, will run more smoothly under load than an inline six. Also, due to the even number of power strokes per revolution, a straight-eight does not produce unpleasant odd-order harmonic vibration in the vehicle's driveline at low engine speeds. The smooth running characteristics of the straight-eight made it popular in luxury and racing cars of

910-464: A variety of factors) requires balance shafts to eliminate undesirable vibration. These take the form of a pair of balance shafts that rotate in opposite directions at twice engine speed, known as Lanchester shafts, after the original manufacturer. In V8 engines , the problem is usually avoided by using a cross-plane crankshaft , and a 180° or single-plane crankshaft is used only in high-performance V8 engines, where it offers specific advantages and

975-399: Is caused by their off-centre crank pins and attached components. The main driving wheels have the greatest unbalance since they have the biggest crankpin as well as the revolving portion of the main rod. They also have the valve gear eccentric crank and the back end of the eccentric rod. In common with the linked driving wheels they also have their own portion of the side rod weight. The part of

1040-401: Is combined with that required for the off-centre parts on the wheel and this extra weight causes the wheel to be overbalanced resulting in hammer blow . Lastly, because the above balance weights are in the plane of the wheel and not in the plane of the originating unbalance, the wheel/axle assembly is not dynamically balanced. Dynamic balancing on steam locomotives is known as cross-balancing and

1105-404: Is two-plane balancing with the second plane being in the opposite wheel. A tendency to instability will vary with the design of a particular locomotive class. Relevant factors include its weight and length, the way it is supported on springs and equalizers and how the value of an unbalanced moving mass compares to the unsprung mass and total mass of the locomotive. The way the tender is attached to

1170-574: The Centurion ARV, and various Dennis fire engines. Despite the shortcomings of length, weight, bearing friction, and torsional vibrations that led to the straight-eight's post-war demise, the straight-eight was the performance engine design of choice from the late 1920s to the late 1940s, and continued to excel in motorsport until the mid-1950s. Bugatti, Duesenberg, Alfa Romeo , Mercedes-Benz , and Miller built successful racing cars with high-performance dual overhead camshaft straight-eight engines in

1235-620: The International Motor Exhibition at Olympia, London in 1920. The Duesenberg brothers introduced their first production straight-eight in 1921. Straight-eight engines were used in expensive luxury and performance vehicles until after World War II. Bugattis and Duesenbergs commonly used double overhead cam straight-eight engines. Other notable straight-eight-powered automobiles were built by Daimler , Mercedes-Benz , Isotta Fraschini , Alfa Romeo , Stutz , Stearns-Knight and Packard . One marketing feature of these engines

1300-471: The Mercedes D.IV . Advantages of the straight-eight engine for aircraft applications included the aerodynamic efficiency of the long, narrow configuration, and the inherent balance of the engine making counterweights on the crankshaft unnecessary. The disadvantages of crank and camshaft twisting were not considered at this time, since aircraft engines of the time ran at low speeds to keep propeller tip speed below

1365-407: The overhead camshaft , three-valve-per-cylinder engine produced 115 brake horsepower (86  kW ) at 4,250  rpm , and was capable of revving to an astonishing (at the time) 5,000 rpm. No Grand Prix engine before the war had peaked at more than 3,000 rpm. Bugatti experimented with straight-eight engines from 1922, and in 1924, he introduced the 2 L Bugatti Type 35 , one of

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1430-526: The 1920s and 1930s. The Duesenberg brothers introduced the first successful straight-eight racing engine in 1920, when their 3 L engine placed third, fourth, and sixth at the Indianapolis 500 . The following year one of their cars won the French Grand Prix , while two others placed fourth and sixth in the race. Based on work the company had done on 16-cylinder aircraft engines during World War I ,

1495-476: The Alvis FV 600 armoured vehicle family. The Alvis Saladin armoured car was a 6x6 design with the engine compartment in the rear, a 76.2mm low pressure gun turret in the centre and the driver in front. The Saracen armoured personnel carrier had the engine in front with the driver in the centre and space for up to nine troops in the rear. The Stalwart amphibious logistics carrier has the driver's compartment over

1560-600: The Duesenberg brothers for the Cord-owned Duesenberg Inc. The automobile manufacturers within the Cord Corporation, comprising Auburn, Cord, and Duesenberg, were shut down in 1937. Lycoming continues to this day as an aircraft engine manufacturer. In the late 1920s, volume sellers Hudson and Studebaker introduced straight-eight engines for the premium vehicles in their respective lines. They were followed in

1625-450: The Imperial luxury model. The British R101 rigid airship was fitted with five Beardmore Tornado Mk I inline eight-cylinder diesel engines. These engines were intended to give an output of 700 bhp (520 kW) at 1,000 rpm but in practice had a continuous output rating of only 585 bhp (436 kW) at 900 rpm. After World War II , changes in the automobile market resulted in

1690-573: The United States it is known as dynamic augment, a vertical force caused by a designer's attempt to balance reciprocating parts by incorporating counterbalance in wheels. Chandler Motor Car The Chandler Motor Car Company produced automobiles in the United States of America during the 1910s and 1920s. Chandler was incorporated in 1913, with Frederick C. Chandler as President, headquartered and with its factory in Cleveland , Ohio. Chandler

1755-418: The applied torque and the resistive torque act at different points along the shaft. It cannot be balanced, it has to be damped, and while balancing is equally effective at all speeds and loads, damping has to be tailored to given operating conditions. If the shaft cannot be designed such that its resonant frequency is outside the projected operating range, e.g. for reasons of weight or cost, it must be fitted with

1820-454: The championship-winning W196 Formula One racing car and the 300SLR sports racing car. The 300SLR was famous for Stirling Moss and Denis Jenkinson 's victory in the 1955 Mille Miglia , but notorious for Pierre Levegh 's deadly accident at the 1955 24 Hours of Le Mans . The 300SLR was the final development of the Alfa Romeo design of the early 1930s as not only the camshaft, but now also

1885-465: The crank throws at high engine rpm , can cause physical contact between the connecting rods and crankcase walls, leading to the engine's destruction. As a result, the design has been displaced almost completely by the shorter V8 engine configuration. The first straight-eight was conceived by Charron, Girardot et Voigt (CGV) in 1903, but never built. Great strides were made during World War I , as Mercedes made straight-eight aircraft engines like

1950-432: The cylinder layout of the engine, as detailed in the following sections. If the weight— or the weight distribution— of moving parts is not uniform, their movement can cause out-of-balance forces, leading to vibration. For example, if the weights of pistons or connecting rods are different between cylinders, the reciprocating motion can cause vertical forces. Similarly, the rotation of a crankshaft with uneven web weights or

2015-648: The decline and final extinction of the straight-eight as an automobile engine. The primary users of the straight-eight were American luxury and premium cars that were carried over from before the war. A Flxible inter-city bus used the Buick straight-eight. During World War II, improvements in the refinery technology used to produce aviation gasoline resulted in the availability of large amounts of inexpensive high octane gasoline. Engines could be designed with higher compression ratios to take advantage of high-octane gasoline. This led to more highly stressed engines which amplified

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2080-597: The design of cars from a long engine compartment between separate fenders to the modern configuration with its shorter engine compartment quickly led to the demise of the straight-8 engine. As a result of this, and of gasoline prices several times as expensive as in the U.S., four- and six-cylinder engines powered the majority of cars in Europe, and the few eight-cylinder cars produced were in the V8 configuration. The British Army selected Rolls-Royce B80 series of straight-eight engines in

2145-591: The early 1930s by Nash (with a dual-ignition unit), REO , and the Buick , Oldsmobile , and Pontiac divisions of General Motors . The Buick straight-eight was an overhead valve design, while the Oldsmobile straight-8 and Pontiac straight-8 straight-eights were flathead engines . Chevrolet, as an entry-level marque, did not have a straight-eight. Cadillac, the luxury brand of General Motors, stayed with their traditional V8 engines. In order to have engines as smooth as

2210-439: The engine (such as the connecting rods) have complex motions, all motions can be separated into reciprocating and rotating components, which assists in the analysis of imbalances. Using the example of an inline engine (where the pistons are vertical), the main reciprocating motions are: While the main rotating motions that may cause imbalance are: The imbalances can be caused by either the static mass of individual components or

2275-486: The first to react to the engineering problems of the straight-eight: in their racing car engines for the P2 and P3 and in their Alfa Romeo 8C 2300/2600/2900 sports cars of Mille Miglia and Le Mans fame the camshaft drive had been moved to the engine centre, between cylinders four and five, thus reducing the aforementioned limitations. The straight-eight was actually built as a symmetrical pair of straight-four engines joined in

2340-442: The following characteristics: Flat-four engines typically use a left–right–right–left crankshaft configuration and have the following characteristics: Flat six engines typically use a boxer configuration and have the following characteristics: This section is an introduction to the balancing of two steam engines connected by driving wheels and axles as assembled in a railway locomotive. The effects of unbalanced inertias in

2405-408: The following characteristics: Straight-four engines (also called inline-four engines ) typically use an up–down–down–up 180° crankshaft design and have the following characteristics: Straight-five engines typically use a 72° crankshaft design and have the following characteristics: Straight-six engines typically use a 120° crankshaft design, a firing order of 1–5–3–6–2–4 cylinders and have

2470-406: The following characteristics: V-twin engines have the following characteristics: V4 engines come in many different configurations in terms of the 'V' angle and crankshaft configurations. Some examples are: V6 engines are commonly produced in the following configurations: [Precision: A 'flat' engine is not necessarily a 'boxer' engine. A 'flat' engine may either be a 180-degree V engine or

2535-417: The frequency of crankshaft rotation, i.e. the fundamental frequency (first harmonic) of an engine. Secondary balance eliminates vibration at twice the frequency of crankshaft rotation. This particularly affects straight and V-engines with a 180° or single-plane crankshaft in which pistons in neighbouring cylinders simultaneously pass through opposite dead centre positions. While it might be expected that

2600-508: The front wheels, the larger B81 engine in the rear and a large load compartment over the middle and rear. The Salamander firefighting vehicle was unarmoured, and resembled the Stalwart with a conventional fire engine superstructure. The Rolls-Royce B80 series of engines were also used in other military and civilian applications, such as the Leyland Martian military truck, the winch engine in

2665-434: The gearbox was driven from the engine's centre. Engineers calculated that torsional stresses would be too high if they took power from the end of the long crankshaft, so they put a central gear train in the middle (which also ran the dual camshafts, dual magnetos, and other accessories) and ran a drive shaft to the clutch housing at the rear. Engine balance#Inherent mechanical balance Engine balance refers to how

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2730-449: The inertial forces produced by moving parts in an internal combustion engine or steam engine are neutralised with counterweights and balance shafts , to prevent unpleasant and potentially damaging vibration. The strongest inertial forces occur at crankshaft speed (first-order forces) and balance is mandatory, while forces at twice crankshaft speed (second-order forces) can become significant in some cases. Although some components within

2795-412: The limitations of the long crankshaft and camshaft in the straight-eight engines. Oldsmobile replaced their straight-eight flathead engine with an overhead valve V8 engine in 1949, at which time Cadillac's V8 was changed to one with overhead valves. Chrysler replaced its straight-eight with its famous Hemi V-8 for 1951. Hudson retired its straight-eight at the end of the 1952 model year. Buick introduced

2860-406: The locomotive can also modify its behaviour. The resilience of the track in terms of the weight of the rail as well as the stiffness of the roadbed can affect the vibration behaviour of the locomotive. As well as giving poor human ride quality the rough riding incurs maintenance costs for wear and fractures in both locomotive and track components. All the driving wheels have an out-of-balance which

2925-400: The locomotive will tend to surge fore-and-aft and nose, or sway, from side to side. It will also tend to pitch and rock. This article looks at these motions that originate from unbalanced inertia forces and couples in the two steam engines and their coupled wheels (some similar motions may be caused by irregularities in the track running surface and stiffness). The first two motions are caused by

2990-471: The main rod assigned a revolving motion was originally measured by weighing it supported at each end. A more accurate method became necessary which split the revolving and reciprocating parts based on the position of the centre of percussion. This position was measured by swinging the rod as a pendulum. The unbalance in the remaining driving wheels is caused by a crankpin and side rod weight. The side rod weights assigned to each crankpin are measured by suspending

3055-476: The middle 1920s Chandler introduced a lower-priced "companion car" called the Cleveland. In 1924, they introduced the "Traffic Transmission," a constant-mesh gearbox that reduced the need for extra clutching when downshifting. This was several years before General Motors offered the "Synchro-Mesh" transmission, which allowed the driver to shift into first gear while moving forward at low speeds. Chandler's peak year

3120-483: The middle at common gear trains for the camshafts and superchargers. It had two overhead camshafts, but only two valves per cylinder. The Alfa Romeo straight-eight would return after World War II to dominate the first season of Formula One racing in 1950, and to win the second season against competition from Ferrari 's V12-powered car in 1951. The Alfa Romeo 158/159 Alfetta was originally designed in 1937 and won 47 of 54 Grands Prix entered between 1938 and 1951 (with

3185-506: The middle class. Engine manufacturer Lycoming built straight-eight engines for sale to automobile manufacturers, including Gardner, Auburn, Kissel, and Locomobile . Hupmobile built their own engine. Lycoming was purchased by Auburn owner Errett Lobban Cord , who used a Lycoming straight-eight in his front-drive Cord L-29 automobile, and had Lycoming build the straight-eight engine for the Duesenberg Model J , which had been designed by

3250-609: The most successful racing cars of all time, which eventually won over 1000 races. Like the Duesenbergs, Bugatti got his ideas from building aircraft engines during World War I, and like them, his engine was a high-revving overhead camshaft unit with three valves per cylinder. It produced 100 bhp (75 kW) at 5,000 rpm and could be revved to over 6,000 rpm. Nearly 400 of the Type 35 and its derivatives were produced, an all-time record for Grand Prix motor racing . Alfa Romeo were

3315-410: The past. However, the engine's length demanded the use of a long engine compartment, making the basic design unacceptable in modern vehicles. Also, due to the length of the engine, torsional vibration in both crankshaft and camshaft can adversely affect reliability and performance at high speeds. In particular, a phenomenon referred to as "crankshaft whip," caused by the effects of centrifugal force on

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3380-422: The pulsations in power delivery vibrate the engine rotationally on the X axis, similar to a reciprocating imbalance. A rotating imbalance is caused by uneven mass distributions on rotating assemblies Types of rotating phase imbalance are: Types of rotating plane imbalance are: Torsional vibration develops when torque impulses are applied to a shaft at a frequency that matches its resonant frequency and

3445-595: The rail, was quantified by Professor Robinson in the U.S. in 1895. He measured bridge deflections, or strains, and attributed a 28% increase over the static value to unbalanced drivers. The residual unbalance in locomotives was assessed in three ways on the Pennsylvania Railroad testing plant. In particular, eight locomotives were tested at the Louisiana Purchase Exposition in 1904. The three measurements were: Qualitative assessments may be done on

3510-424: The reciprocating masses and the last two by the oblique action of the con-rods, or piston thrust, on the guide bars. There are three degrees to which balancing may be pursued. The most basic is static balancing of the off-centre features on a driving wheel, i.e. the crankpin and its attached parts. In addition, balancing a proportion of the reciprocating parts can be done with additional revolving weight. This weight

3575-402: The reciprocating weight is balanced with the addition of an extra revolving weight in the wheel, i.e. still only balanced statically. The overbalance causes what is known as hammer blow or dynamic augment, both terms having the same definition as given in the following references. Hammer blow varies about the static mean, alternately adding to and subtracting from it with each wheel revolution. In

3640-552: The resulting vibration needs to be managed using balance shafts or other NVH -reduction techniques to minimise the vibration that enters the cabin. A reciprocating imbalance is caused when the linear motion of a component (such as a piston) is not cancelled out by another component moving with equal momentum, but opposite in direction on the same plane. Types of reciprocating phase imbalance are: Types of reciprocating plane imbalance are: In engines without overlapping power strokes (such as engines with four or fewer cylinders),

3705-511: The rod on as many scales as there are crankpins or by calculation. The reciprocating piston–crosshead–main-rod–valve-motion link is unbalanced and causes a fore-and-aft surging. Their 90-degree separation causes a swaying couple. The whole locomotive tends to move under the influence of unbalanced inertia forces. The horizontal motions for unbalanced locomotives were quantified by M. Le Chatelier in France, around 1850, by suspending them on ropes from

3770-538: The roof of a building. They were run up to equivalent road speeds of up to 40 MPH and the horizontal motion was traced out by a pencil, mounted on the buffer beam. The trace was an elliptical shape formed by the combined action of the fore-and-aft and swaying motions. The shape could be enclosed in a 5 ⁄ 8 -inch square for one of the unbalanced locomotives and was reduced to a point when weights were added to counter revolving and reciprocating masses. The effect of vertical out-of-balance, or varying wheel load on

3835-563: The speed of sound. Unlike the V8 engine configuration, examples of which were used in De Dion-Bouton , Scripps-Booth , and Cadillac automobiles by 1914, no straight-eight engines were used in production cars before 1920. Italy's Isotta Fraschini introduced the first production automobile straight-eight in their Tipo 8 at the Paris Salon in 1919 Leyland Motors introduced their OHC straight-eight powered Leyland Eight luxury car at

3900-467: The straight-eights of its competitors, Cadillac introduced the crossplane crankshaft for its V8 , and added V12 and V16 engines to the top of its lineup. Ford never adopted the straight-eight; their entry-level Ford cars used flathead V8 engines until the 1950s while their Lincoln luxury cars used V8 from the 1930s to the 1980s and V12 engines in the 1930s and 1940s. Chrysler used flathead straight-eights in its premium Chrysler cars, including

3965-455: The top 180° of crankshaft rotation is greater than in the bottom 180°. Greater distance in the same time equates to higher velocity and higher acceleration, so that the inertial force through top dead centre can be as much as double that through bottom dead centre. The non-sinusoidal motion of the piston can be described in mathematical equations . In a car, for example, such an engine with cylinders larger than about 500 cc/30 cuin (depending on

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4030-413: The vibration is less of a concern. For engines with more than one cylinder, factors such as the number of pistons in each bank, the V angle and the firing interval usually determine whether reciprocating phase imbalances or torsional imbalances are present. Straight-twin engines most commonly use the following configurations: Straight-three engines most commonly use a 120° crankshaft design and have

4095-436: Was 1927, when they sold 20,000 cars. Hopes for continued growth of the market led to overexpansion by the company the following year, which finished 1928 over half a million dollars in debt. In 1929, Chandler Motor Company was purchased by its expanding competitor Hupp Motor Car Company for its factory and manufacturing facilities, and the brand was discontinued. Chandler, like most cars built before all-steel bodies became

4160-573: Was a former designer for the Lozier Motor Company, a top end luxury automobile manufacturer. Chandler and several other Lozier executives left the company to form his company. Chandler concentrated on producing a good quality motor-car within the price range of middle class Americans. Chandlers were well received in the marketplace. In 1920, Chandler had a line of six cars, ranging from $ 1995 to $ 3595. This grew to 10 by 1922, ranging from $ 1495 to $ 2375. Like many other medium-price carmakers, in

4225-422: Was their impressive length — some of the Duesenberg engines were over 4 ft (1.2 m) long, resulting in the long hoods (bonnets) found on these automobiles. In the United States in the 1920s, automobile manufacturers, including Hupmobile (1925), Chandler (1926), Marmon (1927), Gardner (1925), Kissel (1925), Locomobile (1925) and Auburn (1925) began using straight-eight engines in cars targeted at

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