JTD engine

 

JTD/JTDm engine
Manufacturer	Fiat Group/General Motors Maruti Udyog DDiS
Also called:	CDTi (Opel) TiD/TTiD (Saab) DDiS (Suzuki) D (Cadillac)
Production:	1997–present
Displacement:	1.3 L 1248 cc 1.9 L 1910 cc 2.4 L 2387 cc
Block alloy:	cast-iron
Head alloy:	aluminium alloy
Power output:	51 kW (70 PS)-154 kW (210 PS)

JTD (uniJet Turbo Diesel) is Fiat Group's term for its current common rail turbodiesel engine range. The MultiJet name is used in the second generation common rail units. Most of the Fiat, Alfa Romeo and Lancia range has JTD engines. Ownership of the Fiat JTD design is shared with General Motors as part of a settlement of the failed merger between the two auto conglomerates. GM Powertrain Europe group in Turin, Italy manages their interest in these engines. Technological help from Suzuki Motor Corporation, Japan has been taken in the development of this engine.^{[citation needed]}

The JTD Engine: A Breakthrough In Diesel Technology

Compared to conventional injection systems, Unijet injection offers not only a general improvement in performance, but also makes for a far quieter engine (up to 8 dBA quieter, dependent on engine speed).

In conventional diesel injection systems, fuel delivery to the injectors is driven by a mechanical pump. Injection pressure rises as engine speed increases, imposing limits on the optimisation of combustion and the engine’s performance, not to mention its noise and emissions characteristics.

By contrast, with the Unijet system, injection pressure is independent of engine speed and load, since the injection pump generates pressure on a cumulative basis. Moreover, since pump and fuel injectors are electronically controlled, both the injection pressure and fuel quantities injected can be optimised at every point on the power curve.

The system consists of a small pump immersed in the fuel tank which delivers diesel oil to the primary (high pressure) pump (driven by the timing belt), which continuously ‘pushes’ diesel oil into the accumulator. Thus the accumulator tank, or ‘rail’ always contains pressurised oil whatever the engine speed and ‘load’ (the accelerator pedal’s demand for power).

A pressure sensor on the rail and a pressure regulator on the pump respectively monitor oil pressure inside the accumulator, varying fuel pressure continuously. Such precise pressure management across the entire power curve optimises combustion efficiency, thereby producing enhanced performance and fuel economy. That is because the higher the diesel oil pressure entering the injector, the finer the fuel spray produced, making for an enhanced air-fuel mix, more complete combustion and a reduction of exhaust fumes.

However, the higher the pressure inside the combustion chamber, the louder the noise. So the Unijet system combines very high injection pressures with the electronically controlled delivery of minute quantities of diesel fuel to create pre-ignition. Known as pilot ignition, this pre-ignition system takes 200 micro-seconds to deliver just 1.5-2 mm3 of diesel oil, raising combustion chamber temperature and pressure at the moment the piston reaches Top Dead Centre, thus optimising conditions for combustion proper.

Thanks to pilot injection, the heat release curve at the moment of main combustion is very much less steep, and the temperature and pressure peak is also at a lower level. The same amount of energy is produced, but in a more gradual manner. And it is this progressive delivery that drastically reduces engine noise and eradicates the lumpy, clattering noise normally associated with diesel engines.

In order to further optimise combustion, the cylinder intake port is formed in a spiral shape to optimise air swirl. The combination of an atomised fuel spray and swirling air produces an air-fuel mixture that burns ultra-efficiently.

So, common rail technology guarantees enhanced combustion efficiency and better performance; pre-injection offering quieter combustion, easier cold starts and reduced exhaust emissions.

Compared with a traditional, pre-combustion chamber type of unit, a Unijet engine of the same size delivers an average 12% improvement in performance, plus an average 15% reduction in fuel consumption; the saving ranging from 6% at idle to 20% at full power.

1.3

A small 1.3 L (1248 cc) version (called the SDE, Small Diesel Engine) is produced in Bielsko-Biala, Poland. The Multijet 75 PS version was chosen in 2005 as the International Engine of the Year in the 1-litre to 1.4-litre category.

There are three versions of this engine: a  PS ( hp/ kW), a  PS ( hp/ kW) (used in the Fiat Punto, Panda, Palio / Albea, Fiat Idea, Opel Corsa / Combo, Opel Meriva and Suzuki Swift) and a variable inlet geometry  PS ( hp/ kW) (used in the new Fiat Grande Punto, Fiat Linea, Opel Corsa and Opel Astra). At the time of the launch this was the smallest four-cylinder diesel engine available and has a fuel consumption of 72 mpg (3.3 L/100 km) in some applications. The engine is able to meet Euro IV pollution standards without the use of a diesel particulate filter.

applications:

• Fiat 500
• Fiat Doblò
• Fiat Grande Punto
• Fiat Idea
• Fiat Linea
• Fiat Panda
• Fiat Punto
• Lancia Musa
• Lancia Ypsilon
• Opel Agila
• Opel Astra
• Opel Corsa
• Opel Meriva
• Opel Tigra TwinTop
• Suzuki Ignis
• Suzuki Swift
• Suzuki Wagon R

1.6

A 1.6 L version of the engine, with a maximum power output of 120 PS (118 hp/88 kW) was announced for 2006 ^[1]. The new 1.6 JTD diesel will be released before the end of 2007, it comes in two power levels 105 PS and 120 PS.^[2]

1.9

The most common JTD engine is the 1.9 L (1910 cc) straight-4 found in the Fiat Punto, Doblò, Stilo and Croma. It produces  PS ( hp/ kW) and reaches 36 mpg (6.6 L/100 km) in city driving. The first car that used this engine was Alfa Romeo 156 in 1997 ( PS ( hp/ kW)), making it the world's first common rail diesel passenger car. In 1999 it was introduced with the Fiat Punto and Fiat Brava/Fiat Bravo/Fiat Marea. The engine block weighs approximately 125 kg. Most common model found is the 115 PS model as fitted to the Stilo.

The Multijet second generation common rail has three versions. The 8-valve version has 120 PS and 130 PS with variable inlet geometry; and the 16 valve version has 150 PS, that can be found on the Croma.

Opel also uses a version of this engine. Their CDTi engine, manufactured in Pratola Serra, Italy and Kaiserslautern, Germany, is the product of the half-decade joint venture between GM and Fiat.

It is used in the Vectra, Signum, Astra, Zafira, Cadillac BLS and Suzuki SX4 as well as some Saabs marked as TiD. There are three versions of this engine, a 150 PS/320 Nm (148 hp/110 kW), 120 PS (118 hp/88 kW), and 100 PS (99 hp/74 kW).

Fiat Powertrain Technologies has realeased information about new twin stage turbo (twin turbo) version of this engine, there are coming two versions of this engine first one is producing  PS ( hp/ kW) and second one  PS ( hp/ kW), both have a maximum torque output of  N·m ( ft·lbf) at 2000 rpm ( N·m ( ft·lbf) at 1250 rpm). Start of production is forecast July 2007 (180 PS version). The engine weighs approximately 185 kg. This engine will be sold both to Fiat Group Automobiles and other brands, but the 190 PS version is reserved only to Fiat Group Automobiles.^[3]

applications:

• Alfa Romeo 145
• Alfa Romeo 146
• Alfa Romeo 147
• Alfa Romeo 156
• Alfa Romeo 159
• Alfa Romeo GT
• Cadillac BLS
• Fiat Bravo
• Fiat Croma II
• Fiat Doblò
• Fiat Grande Punto
• Fiat Multipla
• Fiat Sedici
• Fiat Stilo
• Lancia Lybra
• Opel Astra
• Opel Signum
• Opel Vectra C
• Opel Zafira
• Saab 9-3
• Saab 9-5
• Suzuki SX4

2.4

The 2.4 L (2387 cc) straight-5 version is based on the 2.4  PS ( hp/ kW) 5 cylinder TD engine as used in the Mk1 Fiat Marea. The JTD version benefits from the solid build of the TD block, and an improved head/injection system. There are 2 versions of the 2.4JTD, the 10-valve as used in the Fiat Marea 130JTD and the earlier Alfa Romeo 156 diesels where it was available as  PS ( hp/ kW), PS ( hp/ kW),  PS ( hp/ kW) and later a 20-valve version  PS ( hp/ kW) as used in the later (2003>) Alfa Romeo 156 as well as some Lancia vehicles. It was designed for transverse front-wheel drive use and was deemed too long and tall for widespread use in other GM or Fiat products. The multijet variant of this engine, capable for  PS ( hp/ kW), is currently used in the Alfa Romeo 159, Alfa Romeo Brera and Fiat Croma. The latest version of this engine produces  PS ( hp/ kW) and  N·m ( ft·lbf) at 1500 rpm, and is used in Alfa Romeo vehicles.^[4]

applications:

• Alfa Romeo 156
• Alfa Romeo Spider
• Alfa Romeo Brera
• Alfa Romeo 159
• Alfa Romeo 166
• Fiat Croma II
• Lancia Kappa
• Lancia Lybra
• Lancia Thesis

Notes

References

• GM, Fiat Reach Settlement Agreement, February 13, 2005 (Press Release)
• Opel Launches 1.9L Diesel at Kaiserslautern Plant. Ward's Auto World. Retrieved on June 13, 2005.
• GM, Affiliates Working OT for Euro Diesels. Ward's Auto World. Retrieved on June 13, 2005.
• GM to create new diesel unit as it untangles its Fiat joint powertrain operations. AutoWeek. Retrieved on June 13, 2005.

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