The Paxman Ventura is a

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

for

railway locomotive A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the us ...

s, built by Davey, Paxman & Co. The type YJ or ''Ventura'' was developed in the mid-1950s as Davey, Paxman's first

high-speed diesel engine High Speed or high-speed may refer to: Films * ''High Speed'' (1917 film), starring Jack Mulhall and Fritzi Ridgeway * ''High Speed'' (1920 film), an American drama directed by Charles Miller * ''High Speed'' (1924 film), featuring Herbert Ra ...

. With a view to the forthcoming

modernisation Modernization theory is used to explain the process of modernization within societies. The "classical" theories of modernization of the 1950s and 1960s drew on sociological analyses of Karl Marx, Emile Durkheim and a partial reading of Max Weber, ...

and

dieselisation Dieselisation (US: dieselization) is the process of equipping vehicles with a diesel engine or diesel engines. It can involve replacing an internal combustion engine powered by petrol (gasoline) fuel with an engine powered by diesel fuel, as o ...

British Railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...

, it was intended as a successor to Paxman's existing medium-speed engine, the direct injection YH. High-speed engines offered higher

power-to-weight ratio Power-to-weight ratio (PWR, also called specific power, or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measuremen ...

s, which in turn allowed locomotives to have a lower

axle loading An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...

and greater route availability. The YJ was to have a weight of less than four tons for a 1,200 hp V12, with versions of 8-, 12- and 16-cylinders. Their construction and reliable use though required more sophisticated manufacture than previously, with better

metallurgy Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sc ...

and balancing of the moving parts for faster running and a stiffer crankcase to avoid vibration.

Description

Like its medium-speed predecessor the Paxman YH, the ''Ventura'' is a 60°

V engine A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder b ...

with 6, 8, 12 or 16 cylinders. The engines are similar in many details and broadly similar in capacity and power; their main differences are in their operating speed, the improvements necessary to achieve this, and the Ventura's resulting lighter weight. The

crankcase 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. Two-stroke engines typically use a crankcase-compression design, resulting in the fuel/a ...

cylinder block 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 attac ...

for MOD Vessels were fabricated from steel by welding a mixture of steel castings and platework This gives a more rigid structure than the YH's cast

light alloy Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 ter ...

block. The aluminium frame of the YH and ZH engines had previously given trouble with cracking and had to be replaced in the Class 17 with a cast iron frame, at Paxman's expense. Both engines have individual aluminium

cylinder head In an internal combustion engine, the cylinder head (often abbreviated to simply "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 ov ...

s for each cylinder.. All other applications had cast iron crankcase / cylinder block. Centrifugally cast iron wet cylinder liners are used with aluminium pistons in both. These pistons have three compression

ring Ring may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell :(hence) to initiate a telephone connection Arts, entertainment and media Film and ...

s and two oil-control rings. The top ring is carried in a cast iron insert. The combustion chamber of this direct injection engine is a toroidal recess in the piston crown. The YJ engines were primarily developed for

diesel electric locomotive A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving wheels ...

s (however Paxmans main design philosophy was maximum power for a given size and weight) and so their crankshafts have the unusual feature of an additional main bearing at the drive end, to help support the weight of the generator armature, where a single-bearing generator can be otherwise unsupported at one end.

Fork and blade connecting rod A connecting rod, also called a 'con rod', is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the cranksha ...

s are used, with the inner rod running on the outside of a shared bearing sleeve. There are four valves per cylinder, driven by pushrods and rockers from a single

camshaft A camshaft is a shaft that contains a row of pointed cams, in order to convert rotational motion to reciprocating motion. Camshafts are used in piston engines (to operate the intake and exhaust valves), mechanically controlled ignition systems ...

between the cylinder banks. The

fuel injector Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All comp ...

is centrally mounted between the valves, and is supplied by a pair of inline fuel injection pumps, one per

bank A bank is a financial institution that accepts deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital markets. Because ...

. The single

turbocharger In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...

is carried above the engine, with its axis longitudinal. Smaller, single bank six- and eight-cylinder engines, the 6YJ and 8YJ, were derived from the V engine. Paxman licensed the Ventura design to

ALCO The American Locomotive Company (often shortened to ALCO, ALCo or Alco) was an American manufacturer of locomotives, diesel generators, steel, and tanks that operated from 1901 to 1969. The company was formed by the merger of seven smaller locomo ...

, with a reciprocal agreement also permitting Paxman to build the popular

ALCO 251 The Alco 251 is a 4-stroke diesel engine that was developed by the American Locomotive Company to replace its 244 and 539 engines. The 251 was developed to be used in diesel locomotives, as a marine power plant in ships, and as a stationary pow ...

. As an indication of the high power / weight ratio of the Ventura, this was around three times that of the 251.

Use

; 12YJ * Class 29, re-engining of the licence-built MAN engines in the NBL Type 2 ( Class 21) diesel-electrics. * Class 42, two units fitted from new to D830 ''Majestic'' for comparison trials. Units rated at 1200 BHp and allied to normal Class 42 spec

Mekydro A torque converter is a type of fluid coupling that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the torque converter connects the power ...

transmissions. ; 6YJ * Class 14 * Class 74 ; 16YJ * Ceylon Government Railways, 15 supplied (14 locos, +1 spare) 1,580 hp *

Hungarian State Railways Hungarian State Railways ( hu, Magyar Államvasutak, MÁV) is the Hungarian national railway company, with divisions "MÁV START Zrt." (passenger transport), "MÁV-Gépészet Zrt." (maintenance), "MÁV-Trakció Zrt." and "MÁV Cargo Zrt" (freig ...

, single engine supplied for trials 1,870 hp *

Type 42 destroyer The Type 42 or ''Sheffield'' class, was a class of fourteen guided-missile destroyers that served in the Royal Navy.Marriott, Leo: ''Royal Navy Destroyers since 1945'', , Ian Allan Ltd, 1989 A further two ships of this class were built for and s ...

, as a set of four generator sets, each rated at 1 MW. *

Type 22 frigate The Type 22 frigate also known as the ''Broadsword'' class was a class of frigates built for the British Royal Navy. Fourteen were built in total, with production divided into three batches. Initially intended to be anti-submarine warfare fri ...

Batch 1 and 2, as a set of four generator sets, each rated at 1 MW.

References

{{Reflist, refs= {{Cite magazine , title=The Ventura – Paxman's high-speed engine , date=May 1964 , magazine=

Modern Railways ''Modern Railways'' is a British monthly magazine covering the rail transport industry which was published by Ian Allan until March 2012, and Key Publishing since then. It has been published since 1962. The magazine was originally based in She ...

, author=R.K. Evans , pages=328–329 {{Cite web , title=Paxman Rail Traction Diesel Engines , url=https://www.paxmanhistory.org.uk/paxraile.htm , publisher=Paxman {{Cite magazine , magazine=

, date=August 1964 , title=New BR 650hp Type 1 Diesel-Hydraulic Locomotive , pages=106–107 Diesel locomotive engines Diesel engines by model Ventura V12 engines V16 engines