The TU family of small

inline-four A straight-four engine (also called an inline-four) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft. The vast majority of automotive four-cylinder engines use a straight-four layout (with the ...

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

s by

PSA Peugeot Citroën The PSA Group (), legally known as Peugeot S.A. (Peugeot Société Anonyme, trading as Groupe PSA; formerly known as PSA Peugeot Citroën from 1991 to 2016) was a French multinational automotive manufacturing company which produced automobiles ...

were introduced in 1986 and used in the

Peugeot Peugeot (, , ) is a French brand of automobiles owned by Stellantis. The family business that preceded the current Peugeot companies was founded in 1810, with a steel foundry that soon started making hand tools and kitchen equipment, and the ...

and

Citroën Citroën () is a French automobile brand. The "Automobiles Citroën" manufacturing company was founded in March 1919 by André Citroën. Citroën is owned by Stellantis since 2021 and previously was part of the PSA Group after Peugeot acquired ...

range of cars. It was first installed in the

Citroën AX The Citroën AX is a supermini which was built by the French manufacturer Citroën from 1986 to 1998. It was launched at the 1986 Paris Motor Show to replace the Citroën Visa and Citroën LNA. Overview Development of this model started in 19 ...

in October 1986, replacing the X family, although it shared many components with its predecessor. The TU is available in either petrol or a naturally aspirated

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...

variant, the latter called TUD. The TU engine is distantly related to the older X-Type engine - sharing a similar

overhead camshaft An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion c ...

architecture, but the key differences are the

belt drive A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulley ...

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 ...

(the X is

chain drive Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles. ...

n), and that the TU is mounted in a conventional upright position with a separate, end-on mounted transmission and unequal length

drive shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power (physics), power and torque and rotation, usually ...

s. The X engine, by comparison, had an integral transmission mounted on the side of 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 ...

(giving rise to its popular nickname the "suitcase engine"), sharing a common oil supply and was mounted almost lying flat on its side within the car. The TU engine is/was used in the following cars: Citroën: AX, Saxo, C2, C3, C4, BX, ZX, Xsara, C15, Nemo and Berlingo. Peugeot: 106, 205, 206, 207, 309, 306, 307, 405, Bipper, Partner and Hoggar, the Iranian

Peugeot 405 The Peugeot 405 is a large family car released by the French automaker Peugeot in July 1987, and which continues to be manufactured under licence outside France, having been discontinued in Europe in 1997. It was voted European Car of the Year for ...

and

Pars Pars may refer to: * Fars Province of Iran, also known as Pars Province * Pars (Sasanian province), a province roughly corresponding to the present-day Fars, 224–651 * ''Pars'', for ''Persia'' or ''Iran'', in the Persian language * Pars News A ...

as well as the Samand Soren and

IKCO Runna The Runna (codenamed X12) is a passenger car made by the Iranian manufacturer IKCO (Iran Khodro). It is a sedan based on the Peugeot 206, and smaller than the IKCO Samand (X7). Overview The Runna was offered with two different four-cylinder e ...

. The TUD engine was only used in 11 cars of which 6 were non-PSA models: the Citroën AX, Citroën Saxo, Citroën Xsara; Peugeot 106, Rover Metro/100-series, Nissan Micra, Maruti Suzuki Zen D/Di and Maruti Suzuki Esteem D/Di and IKCO Samand, and the Tata Indigo 1.4 TD. The Tata's is a smaller version of the TUD engine, based on the 1.5D. PSA has now stopped production of original TU engines, although EC engines, closely related to the TU5 unit, are still in production for emerging markets such as China and Russia and available in both 1.6 and 1.8 litre versions.

TU9

The TU9 was the entry-level version, used in a variety of cars including the

, Saxo,

Peugeot 205 The Peugeot 205 is a supermini (B-segment) car produced by the French manufacturer Peugeot from 1983 to 1999. It was declared "car of the decade" by ''CAR Magazine'' in 1990. It also won ''What Car?s Car of the Year for 1984. The 205 was intro ...

and 106. It had a displacement of , with a

bore Bore or Bores often refer to: *Boredom * Drill Relating to holes * Boring (manufacturing), a machining process that enlarges a hole ** Bore (engine), the diameter of a cylinder in a piston engine or a steam locomotive ** Bore (wind instruments), ...

and a

stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

of . Power was initially , but it was increased to in 1992, with the adoption of central fuel injection and a

catalytic converter A catalytic converter is an exhaust emission control device that converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are usually ...

. Production was stopped in the Citroën Saxo and Peugeot 106 with the introduction of

Euro III The European emission standards are vehicle emission standards for pollution from the use of new land surface vehicles sold in the European Union and EEA member states and the UK, and ships in EU waters. The standards are defined in a ser ...

in 2001. Early versions of this engine suffered premature piston failure which were of a special fuel-saving low-friction design. Symptoms were piston slap, especially with a cold engine, excessive oil consumption and exhaust smoke. PSA repaired the affected vehicles under warranty. This involved fitting a revised piston design and replacement liners.

TU1

The TU1 has a displacement of , with a bore and a stroke of . Power was initially , but it was increased to in 1992, with the adoption of central fuel injection and a catalytic converter. The introduction of

led to the adoption of

multi point injection Manifold injection is a mixture formation system for internal combustion engines with external mixture formation. It is commonly used in engines with spark ignition that use petrol as fuel, such as the Otto engine, and the Wankel engine. In a mani ...

, but power remained the same (although there was a small torque increase). This engine was the entry-level option in the

Citroën C2 The Citroën C2 is a supermini that was produced by the French manufacturer Citroën, with production starting August 2003. It replaced the Citroën Saxo and was built at the Aulnay plant, on the outskirts of Paris. The Citroën C2 was discontin ...

and C3 and

Peugeot 206 The Peugeot 206 is a supermini car (B-segment) designed and produced by the French car manufacturer Peugeot since May 1998 as a replacement to the Peugeot 205. Developed under the codename ''T1'', it was released in September 1998 in hatchback fo ...

TU2

The TU2 has a displacement of , with a bore and a stroke of . Power was initially , powering the Citroën AX Sport, but a slightly more powerful version of the TU24 was developed for the Peugeot 205 Rallye with a longer

intake manifold In automotive engineering, an inlet manifold or intake manifold (in American English) is the part of an engine that supplies the fuel/air mixture to the cylinders. The word ''manifold'' comes from the Old English word ''manigfeald'' (from the ...

and slightly larger venturi size in the

Weber carburetor Weber Carburetors is an automotive manufacturing company founded in 1923, known for their carburetors. History Eduardo Weber began his automotive career working for Fiat, first at their Turin plant (in 1914) and later at a dealership in Bologna ...

s. A new version with was created in 1992 for the Peugeot 106 Rallye, with the adoption of a

Magneti Marelli Magneti Marelli S.p.A. () is an Italian developer and manufacturer of components for the automotive industry. The firm is headquartered in Corbetta, Italy, and includes 86 manufacturing plants, 12 R&D centres, and 26 application centers in 19 c ...

fuel injection system and a catalytic converter. This version in the 106 Rallye uses a different taller TU3 aluminium block to the TU24 (whose block is based on a TU1), different con rod lengths and pistons to the TU24. The aluminium heads also differ slightly in port size and shape with different camshafts. The valve sizes are very slightly different with the TU24 being Inlet / Exhaust. TU2J2 being Inlet and Exhaust with slightly thinner valve stems than the TU24.

TU3

The TU3 has a displacement of , with a bore and a stroke of . This engine has been one of the most used by the PSA Group, with applications in superminis, compacts and midsize cars, including a stint in

competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...

use in the Citroën AX GT Cup and the Citroën AX GTI Cup, held in many European countries throughout the early 1990s in both

circuit racing A race track (racetrack, racing track or racing circuit) is a facility built for racing of vehicles, athletes, or animals (e.g. horse racing or greyhound racing). A race track also may feature grandstands or concourses. Race tracks are also ...

and

rallying Rally is a wide-ranging form of motorsport with various competitive motoring elements such as speed tests (often called ''rally racing),'' navigation tests, or the ability to reach waypoints or a destination at a prescribed time or average speed. ...

. In its early years, it was available with either a single or double barrel carburettor, with fuel injection introduced in 1990 for the AX GTI and 106 XSi, capable of delivering at 6600 rpm. The carburettor versions gave way to fuel injection in 1992, while the sports version was retired in 1996.

ET3

DOHC An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion c ...

16-valve version of the 1360 cc TU3 with

variable valve timing In internal combustion engines, variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with varia ...

was introduced in 2004 with the

Quiksilver Edition. However, this version was named ET3, possibly as a prelude for the new PSA/BMW

Prince engine Prince is the codename for a family of straight-four 16-valve all-aluminium gasoline engines with variable valve lift and variable valve timing developed by PSA Peugeot Citroën and BMW. It is a compact engine family of 1.4–1.6 L in disp ...

family.

TU5

The TU5 has a displacement of , with a bore and a stroke of . It was initially available in 8- and 16-valve configuration, but only the DOHC 16V option remains. The block is made of cast iron and the head is aluminium. Power is in most current applications, the same as the DV6 1.6 L Diesel engine, although a sporty version was used to power the Citroën C2 VTS. The TU5 has been used in motorsports by both Citroën and Peugeot. This engine (JP+ version) was also installed in the Yugo Florida from 2002 until 2008. The latest application is in the

Citroën C-Elysée Citroën C-Elysée is a subcompact (B-segment) sedan produced by the French manufacturer Citroën since 2012, introduced at the Paris Motor Show the same year. It is closely related to the Peugeot 301, launched the same year. It was facelifted i ...

and

Peugeot 301 The Peugeot 301 is a Subcompact (B-segment) sedan produced by the French automaker Peugeot since 2012. It was announced to the public in May 2012, with an official launch that took place at the Paris Motor Show in September. The 301 is built at ...

where it is renamed "EC5". For the Chinese market the engine is named N6A 10FXA3A PSA and produces . TU5 JP+ (NFV) and TU5 JP/L4 (NFT) are almost same engines, but with slight differences. TUG 525

TUD3 and TUD5

The TUD was the diesel variant. An

indirect injection Indirect injection in an internal combustion engine is fuel injection where fuel is not directly injected into the combustion chamber. Gasoline engines equipped with indirect injection systems, wherein a fuel injector delivers the fuel at some po ...

diesel with mechanical pump ( Bosch or

Lucas Lucas or LUCAS may refer to: People * Lucas (surname) * Lucas (given name) Arts and entertainment * Luca Family Singers, also known as "lucas ligner en torsk" * ''Lucas'' (album) (2007), an album by Skeletons and the Kings of All Cities * ''L ...

variants depending on model and year). It initially used the alloy cylinder casings of the TU3 with stronger

wet liner 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 atta ...

s. This was thus called TUD3. This engine was particularly prone to early head gasket failure, a problem that was not completely resolved with the introduction of the TUD5 engine with a more rigid cast iron block. In 1994 displacement was increased to , with a bore and a stroke of , and the block recast in iron with bores directly in the block, the engine being renamed TUD5. Besides a number of applications in the PSA Group's supermini models (AX, Saxo, 106) and Citroën Xsara, it was sold to other automakers who did not possess small diesel engines, such as India's Maruti (who installed it in their Esteem and

Zen Zen ( zh, t=禪, p=Chán; ja, text= 禅, translit=zen; ko, text=선, translit=Seon; vi, text=Thiền) is a school of Mahayana Buddhism that originated in China during the Tang dynasty, known as the Chan School (''Chánzong'' 禪宗), and ...

) and the

Rover Metro Metro, short for metropolitan, may refer to: Geography * Metro (city), a city in Indonesia * A metropolitan area, the populated region including and surrounding an urban center Public transport * Rapid transit, a passenger railway in an urba ...

from 1993 until the end of production in 1997. It also powered the diesel version of the second generation of the

Nissan Micra The Nissan Micra, also known as the , is a supermini car ( B-segment) that has been produced by the Japanese automobile manufacturer Nissan since 1982. The Nissan Micra replaced the Japanese-market Nissan Cherry. It was exclusive to Nissan J ...

in Europe, which wasn't sold in the UK.

References

Sources

Guide des moteurs Peugeot Citroën
(in French) {{PSA Peugeot Citroën TU TU Straight-four engines Diesel engines by model Gasoline engines by model

TU9

TU1

TU2

TU3

ET3

TU5

TUD3 and TUD5

See also

References

Sources