Advanced Automotive Power Systems - Part 2: A Diesel for a Subcompact Car 770113
System analysis studies have shown that Diesel engines can be an alternative to spark ignition engines even in subcompact cars. According to some optimistic estimates, the share of Diesel engines in the total market may reach 25%, so that Diesel engines might well supplement the existing range of spark ignition engines.
During the period from 1970 to 1990, the significance of all individual objectives whose demands are not favorable to the Diesel will decrease, whereas the significance of objectives favoring the Diesel will increase.
It was the objective of the VW Passenger Car Diesel Engine Project to alleviate considerably all the ill-famed Diesel disadvantages, such as noise, smell, smoke, and slow acceleration, the latter being due to the low horsepower-to-weight ratio. On the other hand, we intended to preserve for subcompact car use the classical Diesel advantages, such as excellent fuel economy, long service life, low incidence of malfunctions, and favorable emissions.
We aimend especially for compliance with US emission regulations in addition to meeting requirements worldwide. Compared to a spark ignition engine of the same power output, we intended to improve the fuel economy of the Diesel by 30 to 50%, and its service life by more than 50%.
Another objective was to keep Diesel production cost low by using the largest possible number of spark ignition engine parts for Diesel production.
Of all Diesel operating principles, the swirl chamber design was found to comply best with the manifold requirements connected with a subcompact car. By virtue of extensive development work on the spark ignition engine parts, we ensured that both Otto and Diesel engines can be manufactured on the same transfer line.