THE POTENTIAL TO reduce fuel consumption was the main incentive for starting a diesel engine development at BMW. Compared with gasoline engines of the same rated power, diesels under part load conditions offerupwards of 25 percent improved fuel economy. The new engine, through the use of turbocharging, combines this advantage with the driving performance typical for BMW vehicles.The M 105 is of similar design to the 2.0 to 2.6 liter displacement family of BMW spark ignition engines (1)* These engines, noted for their 6-cylinder, in-line smooth running characteristics, are combined with a compact size, a prerequisite for easier packaging in a wide range of applications. The main components of the diesel and spark ignition versions can be machined on the same transfer lines.The IDI combustion system offers a favorable combination of low fuel consumption, emissions and combustion noise. In particular, under part load conditions it has low particulate emissions. IDI is especially advantageous with small cylinder bores due to shorter flame travel. The offcenter position of the prechamber permits the large valve diameters which are required for high power output.