SYSTEM OVERVIEW:
Our system is based on the "FALLING LEVEL METHOD", consisting of a standard
Pentium® class computer with a color monitor that can be located anywhere
in the area of the knock lab. Graphic terminals are placed by each engine.
The engine's knock meter signals are brought to the computer through a
set of cables with high impedance connections that do not affect the knock
meter readings. With this configuration and the computer's multi-user operating
system, each engine operates independently and an almost unlimited number
of engines can be run simultaneously.
WHAT IS THE FALLING LEVEL METHOD?
Determination of octane rating of fuels can be made using the "FALLING
LEVEL METHOD", a variant of the standard bracketing method used by many
laboratories. A fuel bowl feeding the engine is filled and allowed to empty
as the engine runs. As the fuel level decreases, the fuel/air ratio changes
producing a change in knock intensity of the engine, passing from a light
knock condition through a peak level and back to a light knock. By recording
the level of the peak knock intensity and comparing this level to that
of the known reference fuels, a simple straight line interpolation will
give the octane number of the unknown fuel.
This method differs from the bracketing method only in that the fuel/air ratio
is not adjusted by the operator; this function is accomplished automatically
by the falling level of the fuel in the bowl.
FEATURES:
Eliminates errors in recording, transcribing and calculating octane.
We believe the method is as good as or better than using the usual bracketing
methods and more consistent than rating fuels by the compression ratio
method. The computer is more precise and more consistent than an operator
in determining the peak knock levels of each fuel especially when tests
are run continuously over a full shift when fatigue becomes a factor.
Unlike the standard compression ratio or bracketing methods the operator
is out of the control loop but still has command of the results produced
by the system.
ECONOMICAL:
One computer is used for the entire test lab. The incremental costs
for additional engines beyond the first are very small.
The database generated by this system is tailored to the requirements
of each installation at no additional charge. Reports are also customized
and can be displayed, printed or sent to other systems. Data is stored
permanently and can be transmitted to remote computer systems and or networks.
EASY TO OPERATE:
All interaction between the computer and the operator is done by simple
menus and does not require any prior knowledge of computer operation. Operator
training on the system is accomplished in less than a day and in most cases
leads to substantially more tests per shift. One operator can comfortably
run tests on at least two engines at the same time.
