The following suggestion, or a version of it, will be
implemented by some perceptive auto manufacturer in
the coming years.
Unfortunately, due to entrenched lethargy and inertia
and the not-invented-here syndrome, it is doubtful
that US auto makers will be the first.
But on the off-chance that there is some glimmer of
intelligence up there in Michigan, and being a
patriotic citizen, the following is offered to
Detroit, free of charge (unless they want to sign on a
reasonably-paid consultant ;-) It is a rather
complicated argument, and this is a first draft, but
here is the line of reasoning.
Technically, oxygen is not very reactive; at least not
untill it is converted into ROS (reactive oxygen
species). This usually happens so fast that few of us
are aware that it is a two-step process, nor that the
oxygen molecule itself (as opposed to ROS) is rather
inert without the prior conversion.
This conversion takes away from the net energy which
is available from any combustion process. And it is
not just the energy of converting O2 into ROS which is
the problem, it is also the short timing window.
At 3000 RPM, say, a proportion of air for the entire
displacement of the engine must be converted into ROS
before the O2 will burn. There is simply too little
time, at the 50 times per second allotted (or 25 with
a 4-cycle engine), to do this thoroughly enough to
avoid the dreaded and lossy unburned hydrocarbons.
In the 360 degrees of rotation only a few degrees have
enough available energy content with which to convert
O2 into ROS. This is one reason why you have, in the
typical ICE, what is known as the spark advance. In
effect, this is a form of very tightly timed
*pre-combustion,* and it is surprisingly lossy.
SIDE NOTE: One of the lesser-appreciated reasons why
diesels are more efficient is due to this very
angle, although it is usually stated another way.
IOW the high compression ratio of a diesel, which
should be even lossier, since you can never get a
complete return on the energy of compression, turns
out to be more efficient, and that is because (and
mostly ONLY because) the compression provides
heat-energy but most importantly the GEOMETRY
(spatial) advantage with which to convert more O2 into
ROS in a given amount of time.
In a sense the geometry (lack of space) helps in this
application because O2--ROS has aspects of a chain
reaction. That is to say: O3 is so very reactive that
it reacts even with O2 ... but without the need for
precombustion as in a sparked engine. And once
again, a spark advance can best be described as a
lossy form of precombustion, which would NOT be
necessary if there enough ROS was provide in the
intake mix to begin with.
The 'obvious' part of the situation, then, for
real-world application in automotive design, would be
to covert some O2 to ROS slightly ahead of intake.
Apparently this is either too obvious, or else has
been deemed too difficult or expensive for
implementation before now. That misperception changes
at $100/barrel.
One difficulty, of course, is that you cannot use
regular carburettion, nor even direct manifold fuel
injection. Once you have ROS available - the air
becomes way too reactive, and there is instantaneous
combustion when it touches any fuel. This drawback can
be converted into a feature however.
It should be noted that diesel-style (in-cylinder)
fuel injection is being planned or prototyped for
gasoline ICE usage already, but for other reasons than
precharging air with ROS (less loss from unburned fuel
due to surface-effect cooling on the cylinder walls).
HUGE synergy: Adding diesel-style (in-cylinder) fuel
injection, but along with a precharge of ROS will then
offer a double benefit due to synergy. And eliminate
the need for an ignition system (unless testing shows
that it adds to the fianl efficiency of a complete
fuel burn).
Before regular fuel hit $ 3.75 (my local Chevron
today), the extra cost of in-cylinder fuel injection
and ROS (or as an alternative hydrogen boosters) would
have been too much to consdier as dedicated subsytems.
With fuel at this price, however, and if combustion
can be made substantially - say 25% more-efficient
with a subsystem, even without going to full-hybrid,
then things change and many moderately more costly
concpets become affordable. Onboard hydrogen
generation is another. Either would be offset by
eliminating the catalytic converter, by the way.
The bottom line is that in a low compression engine,
the net energy from combustion should be higher if the
oxygen in air did not need to be converted into ROS by
a pre-combustion advance. Only actual testing will
show this to be valid however, as there are too many
variables to model; but it is my contention that if
ROS is provided by precharging, the engine will not
need the spark-advance (nor possibly the arc discharge
itself) nor need high compression when burning a lean
mix, nor need the catalystic converter - that is an
unbeatable trifecta.
There is
