In the context of CO₂ emission regulations and increase of
energy prices, the downsizing of engine displacement is a widely
discussed solution that allows a reduction of fuel consumption.
However, high power density is required in order to maintain the
power output and a good driveability.
This study demonstrates the potential to strongly increase the
specific power of High Speed Diesel Injection (HSDI) diesel
engines. It includes the technological requirements to achieve high
specific power and the optimal combination of engine settings to
maximize specific power. The results are based on experimental work
performed with a prototype single-cylinder engine (compression
ratio of 14). Tests were conducted at full load, 4000 rpm. Part
load requirements are also taken into account in the engine
definition to be compatible with the targets of new emission
standards. The influence of boost pressure, peak in-cylinder
pressure, injection pressure and nozzle flow rate on full load
limitations (exhaust temperature and smoke level) is studied to
define the technological requirements for a power density of 80, 85
or 90 kW/l.
