Alfa Romeo 159 - 200 bhp 2.4 JTDM 20v
Derived from the familiar 2.4 JTD 20 valve "Common Rail" engine, the new engine has 5 cylinders in line and is the most powerful engine in the JTD multivalve Multijet family, with a specific power of 84 bhp/litre.
The new engine offers numerous advantages. First of all, it is appreciably quieter during the heating stage, depending on the rev speed and ambient temperature. It is also extremely powerful (147 kW - 200 bhp at 4000 rpm), with a generous torque (400 Nm - 40.8 kgm at 2000 rpm).
There are four valves per cylinder, activated via hydraulic tappets and rocker arms by the twin overhead cam shaft. Several changes were made to the new turbodiesel engine to boost performance and engine torque at low speeds, and to eliminate noise and vibration. For example, the "Common Rail" system adopted on the 2.4 JTD Multijet 20v employs two new automatic control strategies for the setting and balance of the injected diesel fuel, to reduce noise and vibration.
The engine includes a number of new components, such as the cylinder head with small stem inlet valves to increase the quantity of inlet air, con rods of fractured steel and a new shape that increases mechanical resistance to the strong stress created by the increased power, an inlet manifold fitted with a throttle valve on one of the two inlet ports of the cylinders to control the turbulence of the air entering; a throttle valve to prevent shaking if the engine stalls, and an intercooler that is highly efficient thanks to its shape and position in the car, to guarantee the optimal temperature and density of the inlet air.
The electronic EGR exhaust gas cooling system has also been modified; the lubricating circuit has a new oil pump and an external air/oil heat exchanger to cool the oil, while the water pump on the cooling circuit is also new. In other words, a long list of improvements and changes that have produced a reliable, powerful engine which is sparing on fuel. Excellent results, achieved thanks to different engine control settings, an increase in the direct injection pressure to 1600 bar, and new turboblower settings. The turboboost is provided by a turboblower with a variable geometry turbo that helps to improve the power delivery, but also generates very high torque even at low engine speeds. In fact, 90% of peak torque is available between 1750 and 3500 rpm. These figures translate into extremely enjoyable driving and brilliant performance: the Alfa 159 has a top speed of 228 km/h and accelerates from 0 to 100 km/h in 8.4 seconds.
Fuel consumption remains low (6.8 l/100 km in the mixed cycle). A new 6-speed sequential automatic transmission isl also available with the 200 bhp 2.4 JTD Multijet 20v engine, a compact light device that incorporates the control unit in the gearbox, and was designed paying particular attention to consumption. On one hand, the use of low friction oil boosts efficiency, while on the other, the sixth speed has been designed particularly for use on the motorway.
