JTDM
Alfa Romeo was first to the market with a Common Rail (JTD) direct injection diesel engine in a passenger car when the Alfa 156 was launched in 1997. This crucial lead in diesel technology has not been squandered and is now available in three outstanding engines.
MultiJet Technology
Within a UniJet engine, a pilot injection raises temperature and pressure inside the cylinder to improve combustion at the time of the main stroke. However, by dividing the main injection into a number of smaller injections, a MultiJet engine affords a fuller, more gradual combustion whilst the amount of diesel burnt at each stroke remains the same. Thus facilitating smoother, quieter combustion, reduced emissions and increased performance.
Thus a MultiJet engine differs from its UniJet counterpart in two essential areas; the injectors and the electronic control unit.
To facilitate multi-injection, the new injectors can both reduce the time lag between injections from 1500 to just 150 microseconds, and reduce the minimum quantity of fuel injected from 2 to less than 1 cu mm. In tandem, the new control unit modulates injection strategy continually to adjust to changes within three parameters; engine rpm, torque required at any given time by the driver and coolant temperatures.
Thus, when coolant temperature is less than 60 degrees and torque requirement low, two small and one large injections are performed. As torque demand increases, the number of injections drops to two; one small and one large. Under conditions of high rpm and high torque demand, only one injection is required whilst, with coolant temperature at over 60 degrees, emissions are minimised with one small, one large, then one small injection in the sequence.
Hence, start-up times and exhaust smoke are reduced, noise levels and vibration are lowered to ensure a quieter drive and improved passenger comfort, fuel consumption is reduced and emissions are drastically lower.
1.9 JTDM
1910cc
120bhp (88 kW) at 4000rpm
Peak torque 275Nm (28kgm) at 2000 rpm
1.9 JTDM 16v
1910cc
150bhp (110 kW) at 4000rpm
Peak torque 305Nm (31kgm) at 2000 rpm in the Alfa 147 and GT
Peak torque 320Nm (32.6kgm) at 2000rpm in the Alfa 159
2.4 JTDM
2387cc
200bhp (147 kW) at 4000rpm
Peak torque 400Nm (40.8kgm) at 2000 rpm
