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Otto Alternates and Diesel Diversions
By Ron
Cairns
Split cycle engines have been
around since the early 1910’s. Carmelo Scuderi invented this
month’s engine in 2001 and since his death in 2002, his sons have
been working to improve their father’s design and bring this engine
into main stream use.
“The innovations in the
design of the Scuderi engine reduces the cost of diesel systems by
eliminating or dramatically reducing three of the most expensive
and complex parts of a diesel system - turbo charging, injectors
and exhaust treatment,” says Sal Scuderi, “Because of the design
advantages, we estimate this can lower the cost of diesel engines
by as much as 40 to 50 percent.”
Scuderi’s split cycle engine
splits the 4 strokes of the cycle between two cylinders. Under
normal operation air is compressed and flows through the cross over
passage and is utilized during combustion in the power cylinder. It
is really a dedicated compressor on one side and an engine on the
other. One cylinder does the intake and compression stroke while a
totally separate cylinder does the expansion and exhaust strokes.
The two cylinders are connected by a passage way that allows air to
flow from the compression cylinder in the expansion cylinder but
doesn’t allow reverse air flow.
As the compression intake
cylinder has its own crankshaft journal, it can have a different
stroke than the expansion/exhaust stroke cylinder. It’s partially
this difference that accounts for the increased power
output.
Another major difference with
this engine is the point at which ignition occurs. In a
conventional engine it happens at about 20 degrees before
the piston reaches its peak cylinder pressure position. In the
Scuderi Split cycle engine the spark plug fires 10 to 15 degrees
after reaching peak cylinder pressure position.
As the two cylinders have
their own separate crank journals, the strokes can be different
from each other. There are some exciting possibilities with this
arrangement such as a compression stroke that is shorter than the
expansion stroke but the compression cylinder can have a larger
bore than the expansion cylinder so that its volume is greater than
expansion cylinder, giving you a built in compressor and super
charger.
An Air-Hybrid
Design
By adding a small air storage
tank with some simple controls costing only a few hundred dollars,
the Scuderi engine can recapture energy normally lost during the
braking of a vehicle.
The Scuderi Air-Hybrid
feature with the most significant impact on cost may well be the
reduction or total elimination of the exhaust treatment system.
Because the unique method of firing after top dead center is
combined with a very fast moving power piston, the two biggest
emission problems for diesel engines, (NOx and soot) are eliminated
or drastically reduced
More information on this
engine can be found on their website, www.scuderigroup.com | 