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 some question as to how much more energy would be available under such circumstances, but not one doubts that it is substantial. My feeling is that it is in the range of 25% additional. BTW - the known expense of high pressure (20,000 psi and up) diesel injectors is often mentioned as the downside of diesel-style (in-cylinder) fuel injection. A point should be made now that injectors are costly mostly because they must provide a throttling or variable input of fuel, while at the same time overcoming a very high compression regime. With a lower compression engine, say 8-1 ratio, which comes with a precharge of ROS, less pressure is required for in-cylinder injection; but also, the big variable is in converting the ICE to SINGLE SPEED, which is the largest possible improvement since you can then match the torque and power curves... albeit an improvement which demands a full hybrid design - since it negates the need for having a throttling variability in the fuel supply. But why not go all out? The gasoline (biofuel) injector of a hybridized setup, i.e. one with an electric motor as the driving force for turning the wheels, then become only a simplified pump, which operates at full-speed or else the engine is turned off. There is no idle and no intermediate speed. When a small battery pack is low, the engine comes on automatically and silently, when the pack is charged, the engine turns off automatically. It does not, in fact it cannot idle, although some throttling could be provided by the amount of ROS which is made- that will provide some latitude. At the expense of being too wordy in this draft- Back to the all-important but generally neglected importance of ROS to automotive design. Ozone is one type of ROS, possibly the main type, and of course is the reactive molecule made of three oxygen atoms. It's reactive because the oxygen atom (as opposed to the molecule) is strongly electronegative and the three strongly electronegative atoms are loosely bound together, whereas in a singe O2 molecule, the bond is comparatively strong. Ozone also is fairly stable as an ion, once it is formed. This too is not well appreciated. All of this means together that ozone and other ROS, made "on-the-fly" immediately prior to intake, has a huge potential to steal electrons from less electronegative molecules, even nitrogen, to give a complete burn to a lean mix, while requiring low compression. Of course reactivity is why ozone is so toxic when unburned, but in this concept, O3 is never stored, and does not survive the power stroke, and none ends up in the exhaust. Finally, as to net costing of the additional hardware, when O3 or other ROS is precharged into an ICE intake, it is suspected that this feature will dispense with both the need for high compression, and possibly the need for any spark ignition at all. Again, realize that ozone can be naturally generated by UV radiation, even a UV bulb, and once created has a surprisingy long life. Ozone may also be facilitated by catalysis and enhanced of by other high energy reactions, such as electrical discharge or radioactivity, or especially by a combination technique employing all of the above along with waste heat and catalysis. Waste heat has the disadvatage of lowering the lifetime however, but there is a balance. More details to follow ... (if Lutz's successor at GM does not hire me on first to get this concept moving forward ;-} as I doubt if Bob himself would be amenable due to all the nice things said about him here recently) Jones
