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In an internal combustion engine, the engine block is the structure which contains the cylinders and other components. In an early automotive engine, the engine block consisted of just the cylinder block, to which a separate crankcase was attached. Modern engine blocks typically have the crankcase integrated with the cylinder block as a single component. Engine blocks often also include elements such as coolant passages and oil galleries.
The term "cylinder block" is often used interchangeably with "engine block", although technically, the block of a modern engine (i.e. multiple cylinders integrated with another component) would be classified as a monobloc.
The main structure of an engine typically consists of the cylinders, coolant passages, oil galleries, crankcase, and cylinder head(s). The first production engines of the 1880s to 1920s usually used separate components for each of these elements, which were bolted together during engine assembly. Modern engines, however, often combine many of these elements into a single component in order to reduce production costs.
The evolution from separate components to monobloc engine blocks has been a gradual progression since the early 20th century. The integration of elements has relied on the development of foundry and machining techniques. For example, a practical low-cost V8 engine was not feasible until Ford developed the techniques used to build its flathead V8 engine. Those techniques were then applied by other manufacturers to their engines.
A cylinder block is the structure which contains the cylinder, plus any cylinder sleeves and coolant passages. In the earliest decades of internal combustion engine development, cylinders were usually cast individually, so cylinder blocks were usually produced individually for each cylinder. Following that, engines began to combine two or three cylinders into a single cylinder block, with an engine combining several of these cylinder blocks.
In early engines with multiple cylinder banks –such as V6, V8, or flat-6 engines –each bank was typically made of one or multiple separate cylinder blocks. Since the 1930s, mass production methods have developed to allow both banks of cylinders to be integrated into the same cylinder block.
Wet liner cylinder blocks use cylinder walls that are entirely removable, which fit into the block by means of special gaskets. They are referred to as "wet liners" because their outer sides come in direct contact with the engine's coolant. In other words, the liner serves as the entire cylinder wall, rather than being merely a sleeve.
Advantages of wet liners are a lower mass, reduced space requirements, and coolant being heated faster from a cold start, which reduces start-up fuel consumption and provides heating for the car cabin sooner.
Dry liner cylinder blocks use either the block's material or a discrete liner inserted into the block to form the backbone of the cylinder wall. Additional sleeves are inserted within, which remain "dry" on their outside, surrounded by the block's material.
For either wet or dry liner designs, the liners (or sleeves) can be replaced, potentially allowing an engine overhaul or rebuild without replacing the block itself, although this is often not a practical repair option.
The crankcase is the structure that houses the crankshaft. As with cylinder blocks, this is primarily an integrated component in modern engines.
Engine blocks are normally cast from either cast iron or an aluminium alloy. Aluminium blocks are much lighter in weight and transfer heat more effectively to coolant, but iron blocks retain some advantages, such as durability and reduced thermal expansion.
An engine where all the cylinders share a common block is called a monobloc engine. Most modern engines use a monobloc design of some type, and few modern engines have a separate block for each cylinder. This has led to the term "engine block" usually implying a monobloc design, with "monobloc" itself rarely being used.
In the early years of the internal combustion engine, casting technology couldn't produce large castings with complex internal cores (for water jackets etc). Most early engines, particularly those with more than four cylinders, had their cylinders cast as pairs or triplets of cylinders, then bolted to a separate crankcase.
As casting techniques improved, an entire cylinder block of 4, 6, or 8 cylinders could be produced in one piece. This monobloc construction was simpler and more cost-effective to produce. For straight engine cylinder layouts, this meant that all the cylinders, plus the crankcase, could be produced in a single component. One of the early engines produced using this method is the 4-cylinder engine in the Ford Model T, introduced in 1908. The method spread to straight-six engines and was commonly used by the mid-1920s.
Up until the 1930s, most V engines retained a separate block casting for each cylinder bank, with both bolted onto a common crankcase (itself a separate casting). For economy, some engines were designed to use identical castings for each bank, left and right. [2] : 120 A rare exception was the Lancia 22½° narrow-angle V12 of 1919, which used a single block casting combining both banks. [2] : 50–53 The Ford flathead V8 –introduced in 1932 –represented a significant development in the production of affordable V engines. It was the first V8 engine with a single engine block casting, putting a V8 into an affordable car for the first time. [3]
The communal water jacket of monobloc designs permitted closer spacing between cylinders. The monobloc design approach also improved the torsional rigidity of engines, as cylinder numbers, engine lengths, and power ratings increased.
Most engine blocks today, except some unusual V or radial engines and large marine engines, use a monobloc design with one block for all cylinders, plus an integrated crankcase. In such cases, the skirts of the cylinder banks form a crankcase area of sorts, which is still often called a crankcase despite no longer being a discrete part.
Use of steel cylinder liners and bearing shells minimizes the effect of the relative softness of aluminium. Some engine designs use plasma transferred wire arc thermal spraying, instead of cylinder sleeves, to further reduce weight. These types of engines can also be made of compacted graphite iron, such as in some diesel engines. [4]
Some modern consumer-grade small engines use a monobloc design where the cylinder head, block, and half of the crankcase share the same casting. One reason for this, apart from cost, is to produce an overall lower engine height.[ citation needed ] The primary disadvantage can be that repairs become more time-consuming and perhaps impractical.
An example of engines with integrated cylinder heads are the Honda GC-series and GXV-series engines, which are sometimes called "Uniblock" by Honda. [5]
Several cars with transverse engines, have used an engine block consisting of an integrated transmission and crankcase. Cars that have used this arrangement include the 1966-1973 Lamborghini Miura [6] and cars using the BMC A-series and E-series engines. [7] [8] This design often results in the engine and transmission sharing the same oil.
Motorcycles such as the Honda CB750 use a similar layout, with the cylinder block and crankcase integrated with part of the transmission.
Many farm tractor designs have the cylinder block, crankcase, transmission, and rear axle integrated into a single unit. An early example is the Fordson tractor.
In an internal combustion engine, the cylinder head sits above the cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas in more modern overhead valve and overhead camshaft engines, the cylinder head is a more complicated block often containing inlet and exhaust passages, coolant passages, valves, camshafts, spark plugs and fuel injectors. Most straight engines have a single cylinder head shared by all of the cylinders and most V engines have two cylinder heads.
The Rover K-series engine is a series of internal combustion engines built by Powertrain Ltd, a sister company of MG Rover. The engine was a straight-four cylinder built in two forms, SOHC and DOHC, ranging from 1.1 to 1.8 L; 67.9 to 109.6 cu in.
The Ford 335 engine family was a group of engines built by the Ford Motor Company between 1969 and 1982. The "335" designation reflected Ford management's decision to produce an engine of that size with room for expansion during its development. This engine family began production in late 1969 with a 351 cu in (5.8 L) engine, commonly called the 351C. It later expanded to include a 400 cu in (6.6 L) engine which used a taller version of the engine block, commonly referred to as a tall deck engine block, a 351 cu in (5.8 L) tall deck variant, called the 351M, and a 302 cu in (4.9 L) engine which was exclusive to Australia.
In a reciprocating engine, the cylinder is the space in which a piston travels.
The Oldsmobile V8, also referred to as the Rocket, is a series of engines that was produced by Oldsmobile from 1949 until 1990. The Rocket, along with the 1949 Cadillac V8, were the first post-war OHV crossflow cylinder head V8 engines produced by General Motors. Like all other GM divisions, Olds continued building its own V8 engine family for decades, adopting the corporate Chevrolet 350 small-block and Cadillac Northstar engine only in the 1990s. All Oldsmobile V8s were manufactured at plants in Lansing, Michigan while the engine block and cylinder heads were cast at Saginaw Metal Casting Operations.
An overhead valve (OHV) engine, sometimes called a pushrod engine, is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with flathead engines, where the valves were located below the combustion chamber in the engine block.
The term Cadillac V8 may refer to any of a number of V8 engines produced by the Cadillac Division of General Motors since it pioneered the first such mass-produced engine in 1914.
The Ford flathead V8 is a V8 engine with a flat cylinder head designed by the Ford Motor Company and built by Ford and various licensees. During the engine's first decade of production, when overhead-valve engines were used by only a small minority of makes, it was usually known simply as the Ford V‑8, and the first car model in which it was installed, the Model 18, was often called simply the "Ford V-8", after its new engine. Although the V8 configuration was not new when the Ford V8 was introduced in 1932, the latter was a market first in the respect that it made an 8-cylinder affordable and a V engine affordable to the emerging mass market consumer for the first time. It was the first independently designed and built V8 engine produced by Ford for mass production, and it ranks as one of the company's most important developments. A fascination with ever-more-powerful engines was perhaps the most salient aspect of the American car and truck market for a half century, from 1923 until 1973. The engine was intended to be used for big passenger cars and trucks; it was installed in such until 1953, making the engine's 21-year production run for the U.S. consumer market longer than the 19-year run of the Ford Model T engine for that market. The engine was on Ward's list of the 10 best engines of the 20th century. It was a staple of hot rodders in the 1950s, and it remains famous in the classic car hobbies even today, despite the huge variety of other popular V8s that followed.
In a piston engine, the crankcase is the housing that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block.
In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, from front to back.
A motorcycle engine is an engine that powers a motorcycle. Motorcycle engines are typically two-stroke or four-stroke internal combustion engines, but other engine types, such as Wankels and electric motors, have been used.
The Paxman Ventura is an internal combustion diesel engine for railway locomotives, built by Davey, Paxman & Co.
A junk head is a form of piston engine cylinder head, where the head is formed by a dummy piston mounted inside the top of the cylinder. In most other engine designs, the cylinder head is mounted on top of the cylinder block. That form has also been termed a "poultice head".
A monobloc or en bloc engine is an internal-combustion piston engine some of whose major components are formed, usually by casting, as a single integral unit, rather than being assembled later. This has the advantages of improving mechanical stiffness, and improving the reliability of the sealing between them.
The Standard wet liner inline-four engine was an inline four cylinder petrol engine produced by the Standard Motor Company. Originally developed concurrently for passenger car use and for the Ferguson TE20 tractor, it was widely used for Standard passenger cars of the 1950s, most notably the Vanguard. Later it was successfully used in Standard's popular early generation Triumph TR series sports cars.
A long-bolt or through-bolt engine is an internal combustion piston engine where, following usual practice, the cylinder head is held down by bolts or studs. Conventionally the cylinder head is bolted to the cylinder block and the crankshaft main bearings are in turn bolted to the crankcase by separate bolts. In the long-bolt engine however, a single set of long bolts is used, spanning from the cylinder head right through to the crankshaft bearing caps.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
The Ferrari flat-12 engine family is a series of flat-12 DOHC petrol engines produced by Ferrari from 1964 to 1996. The first racing Ferrari flat-12, the Mauro Forghieri-designed Tipo 207, was introduced in the Ferrari 1512 F1 car in 1964. Later flat-12 racing engines were used in Ferrari Formula One and sports racing cars from 1968 until 1980, including the 212 E Montagna, 312 B series, 312 PB and 312 T series. The roadgoing flat-12 engines were introduced with the 365 GT4 BB and were produced in various versions until the end of F512M production in 1996.
The Mercedes-Benz OM629 is a 4.0 litres (3,996 cc) diesel-fuelled, 4-stroke, compression-ignition internal combustion 75° 32-valve V8 engine used in the 2000s.
The Volkswagen-Audi V8 engine family is a series of mechanically similar, gasoline-powered and diesel-powered, V-8, internal combustion piston engines, developed and produced by the Volkswagen Group, in partnership with Audi, since 1988. They have been used in various Volkswagen Group models, and by numerous Volkswagen-owned companies. The first spark-ignition gasoline V-8 engine configuration was used in the 1988 Audi V8 model; and the first compression-ignition diesel V8 engine configuration was used in the 1999 Audi A8 3.3 TDI Quattro. The V8 gasoline and diesel engines have been used in most Audi, Volkswagen, Porsche, Bentley, and Lamborghini models ever since. The larger-displacement diesel V8 engine configuration has also been used in various Scania commercial vehicles; such as in trucks, buses, and marine (boat) applications.