The interesting idea!

• For 130 years, the engine valves have been pushed open by camshafts and against very strong valve springs. No one seems to have ever explored any other possibilities!

• The thought that occurs to me is to get rid of the camshaft completely! Install VERY POWERFUL electrical solenoids. It seems certain that a 100-watt or 1000-watt solenoid should be able to OPEN a valve VIRTUALLY INSTANTLY! A second similar solenoid should be able to CLOSE that valve just as fast.

• Rather than the existing situation where each valve GRADUALLY opens due to the leverage of the camshaft lobe, this concept would allow IMMEDIATE AND FULL FLOW. A standard camshaft lobe causes each valve to follow a (roughly) sinusoidal path regarding being opened. A mathematical Integration of that motion shows that the actual total airflow is only around HALF of what would theoretically be possible. So, it seems to me that if extremely strong solenoids forced the valves to SNAP open and closed, almost every aspect of engine performance should improve ENORMOUSLY!

• There would be NO wasted gas-air mixture passing through the cylinders, because those two valves would NEVER both be open at the same time! Better fuel mileage.

• The exhaust valve would NEVER open until AFTER the POWER stroke was totally completed, so an increase in the net power output of the engine should result.

• With the intake and exhaust valves being WIDE OPEN instantly, far easier and better flow of fuel INTO the cylinder should occur, meaning greater engine power output, and far better purging of exhaust gases should also occur, allowing more available volume in the cylinder for the next incoming INTAKE stroke.

• BETTER fuel mileage AND much greater power production! Seems to me that Detroit Engineers should have thought of this 50 years ago! But the concept of an engine without a camshaft is probably too "outside the box" for the traditional thinking of corporate engine designers! Oh, well! But that would certainly be one of MY first areas of exploration if I had authority in Detroit! It sure sounds extremely obvious to me! Granted that there might be technical problems that cause it to not be usable, but if Detroit is spending countless billions on E-85 engine designs (dead meat!) and Hydrogen fuel-cells (20 to 50 years from now) and battery power (a 1980s-90s concept which had dismally failed), spending a few bucks to try really high-powered solenoids seems worth trying!

• If you have actually followed all of this, you now pretty much know most of the design basics in case you ever decide to invent your own engine for your car! Very few people seem to have even heard of much of this, and very few auto mechanics seem to know about these things or understand them. I sort of wonder how many of the Engineers at the automakers really know the Physics behind what they make blueprints for! The mysterious way that large free-flowing radiators gave way to the smaller obstructed radiators of today make me wonder if they had really understood these things before 1980 or so! I would hope that engine designers of 1910 knew most of these things, because it is all just simple physics! At least they SHOULD HAVE KNOWN!

• For discussion's sake, consider a hypothetical situation resembling the last drawing shown above. The crankshaft throw is fully horizontal, for the greatest possible geometrical mechanical transfer of torque to the crankshaft. Imagine that the full 6300 pound downward force on the piston could be applied under these circumstances. The torque transferred to the crankshaft would be 6300 * 1.0 * 0.146 or 920 foot-pounds of torque! This rather obvious result is many times higher than any actual automotive engine can develop! It would also be relatively constant, and would not decrease at high or low engine speeds.

• This geometrical mechanical advantage was a standard feature of the old steam engine locomotives, where the entire available steam force was always applied at the best possible mechanical advantage. In comparison, internal combustion engines are rather pitiful regarding mechanical efficiency! However, this hypothetical arrangement is not possible in a normal automotive engine. It is easy to see from geometrical analysis that the piston necessarily has dropped exactly halfway down the cylinder, with the loss of almost all compression advantages and there is no flexibility on this point.

• It is not commonly known, and certainly seldom published, that the very best experimental automotive internal combustion engines are only around 28% efficient, when considering the energy in the gasoline and that actually developed in the spinning crankshaft. Many of the common automobile engines today are only around 21% efficient. (This is actually considered good, since common automotive engines of 1970 had BELOW 15% thermal efficiency!) (It has actually risen a little from that.)

• "Ground transportation vehicles are powered, by and large, exclusively by internal-combustion engines. In passenger vehicles in particular, the thermal efficiency of the [engine] cycle is of the order of 10 to 15 percent."from Mark's Standard Handbook for Mechanical Engineers, Tenth Edition (1995), page 9-29.

• (That particular reference had been composed for an earlier Edition of Marks of the late 1970s, and the number had gotten somewhat outdated by the 1995 Edition.)

• In the discussion above, we have seen WHY the overall efficiency is so dreadfully low for ICEs. The cooling system MUST get rid of around 40% of the fuel's energy, just to keep the engine from melting down or warping and failing. And the exhaust gases MUST carry away around another 40% of the energy from the fuel. That only leaves around 20% left which can be converted into useful mechanical energy. Yes, tweaking the exhaust system to reduce hot exhaust gas flow can help, but that also restricts the flow of air/oxygen INTO the cylinders and also creates more work for the pistons to do in pushing the gases out. Ditto, adding a turbocharger (a supercharger that increases the amount of oxygen/air pushed into the cylinders) which is powered by the exiting hot exhaust gases generally DOES have a positive benefit, but the improvement due to having more fuel-air to burn has to overcome the significant power required to force the exhaust out even harder in order to spin the turbine in the turbocharger. No free lunch!

• By increasing the temperature of the thermostat, in other words, reducing the effectiveness of the cooling system and making the engine run hotter, a SLIGHT improvement in fuel economy is achieved. However, the hotter engine tends to heat incoming air up which REDUCES the air density and therefore reduces the power produced by the engine. Now you know WHY the engine seems to have more power if you replace the modern 195°F thermostat with a 165°F one, but the engine creates more pollution due to poorer burning and it also has worse gas mileage.

• Engine manufacturers have come up with many dozens of different ideas to try to (incrementally) reduce the heat carried away by the cooling system and/or the heat carried away in the exhaust. But as just noted, all such changes tend to also have negative effects as well as the desired positive ones. And so the fact that most modern vehicles now on the road have around 21% overall thermal efficiency is NOT likely to significantly change, IF ICEs are used in the future.

• Comment: You have certainly noticed that car manufacturers have been trying to explore hybrid cars, electric cars, fuel cell (hydrogen) cars, ethanol (E-85) (for a while) and many goofy ideas. Yes, they partly are doing that because the public is wound up over all the energy issues in the news. But doesn't it seem strange that they are spending billions of dollars on ideas which never seem to work out? There IS a reason that they never bother to tell us about! Around 2004, I discovered some PUBLISHED reports by the Oil Institute and other related organizations, which presented the data on consumption, usage and supplies of fossil fuel supplies. It scared the daylights out of me! Those (published) Reports were somewhat tricky in how they present the data, where it was difficult to compare the values of the data on consumption, usage and supplies (for each country and each year), but once the data is converted into the same units, the REMAINING EXISTING SUPPLIES are VERY low. That data indicated that the US (then) only had enough known petroleum to supply our current needs for just over FOUR YEARS (if no imports were made). The people who think natural gas is the answer for the future would see that only EIGHT years of supply of that was in the ground under America. That data (now updated with newer data from their June 2010 Report) is at Energy Supplies. SEE why the automotive engine manufacturers are trying to find some NEW ways to power the products they hope to sell in the future?

• YOU can actually confirm the overall efficiency for yourself with your own car! I will use the example of one my Corvettes. At a constant 60 mph on a straight and level Interstate Highway, I get around 25 mph, which sounds GOOD for a Corvette! OK. According to GM information, the frontal area of the car is around 19 square feet, the aerodynamic coefficient of drag (due to the shape of the car, and which is fairly constant for different speeds) is 0.330 and the tire resistance drag is around 0.015 (depending on tire type, inflation pressure, temperature and speed). From this we can calculate that the Aerodynamic Drag at 60 mph (88 ft/sec) is 19 * 0.330 * (88)2/(13*32) pounds of force (the last factor being the air density in slugs per cubic foot), which gives 116.7 pounds of aerodynamic drag, at 60 mph. (at 70 mph, it is easy to calculate that it rises to 158.9 pounds.) Tire resistance drag is 0.015 * 3200 pounds (the vehicle weight) or 48 pounds at 60 mph (and around 60 pounds at 70 mph). This makes the Total Drag as 116.7 + 48 or 164.7 pounds at 60 mph (and 218.9 pounds at 70 mph) (and 51.9 + 32 or 83.9 pounds at 40 mph).

• Clarification Note: Many articles and web-pages, and even many respected textbooks (including Marks), contain a serious error regarding the subject of the previous paragraph. They apparently see the V2 in the formula for Aerodynamic Drag, and they must believe that is therefore referring to some relationship to Kinetic Energy (which is 1/2 * M * V2), so they add in a 0.5 in their formulas! Nope! It only turns out that it is a fluke that there are two Vs in there and they happen to be identical! The relationship is actually one regarding the analysis of the Momentum (lb-ft) of the air colliding with the frontal area of the vehicle. FIRST, we are HITTING the air with a velocity of 88 ft/second. SECOND, the AMOUNT of air that we are hitting is given by the density of air times its cross-sectional area, times its "length" (per second). The coefficient of drag is essentially telling how quickly the air gets out of the way of the vehicle! So the correct formula is D = r * CD * S * V2, indicating the usual designations for the air density rho, the coefficient of drag, the frontal area of the vehicle and air velocity. The formula might be more clearly written as D = CD * V * ( S * V * r), where the contents of the parentheses are simply the mass-flow rate of the air, each second (or slugs / second). Multiply this by the velocity and end up with a Force!

• At 60 mph, the total required horsepower to overcome this and maintain a constant speed is 164.7 * 88 / 550 or 26.4 horsepower. (at 70 mph it is 40.9 HP, a considerably higher drag load!) (the 550 is to convert feet-pounds per second into horsepower.) A horsepower is equivalent to 2544 Btu/hr (from above) so this is 67,200 Btu/hr (26.4 * 2544) of needed (or usable) output. In one hour of driving at that constant speed, we would therefore use up an amount of energy equal to 67,200 Btu. (at 70 mph, 104,000 Btu.)

• A gallon of nearly any type of gasoline contains around 126,000 Btu of chemical energy. In the hour of driving, I would cover 60 miles and get the 25 mpg, which means that I would use 60/25 or 2.4 gallons of gasoline. That much gasoline has 126,000 * 2.4 or 302,000 Btus in it. Since the car used 67,200 Btu to maintain that 60 mph constant speed, the overall thermal efficiency is 67,200/302,000 or 22.2%.

• At 70 mph, I tend to get around 21 mpg, and therefore would use up 3.3 gallons in traveling those 70 miles, or a gasoline energy content of 420,000 Btu. So we would have 104,000/420,000 or around 24.8% overall thermal efficiency. Interestingly, the thermal efficiency is actually higher at the higher speed, but it is more than overcome by the far greater total drag, which is why gasoline mileage goes down at high speeds.

• A primary reason for this disappointing efficiency is this unfortunate mechanical arrangement where the majority of the force applied to the top of the pistons is NOT able to get transferred into torque in the crankshaft but instead attempts to drive the whole crankshaft down out of the engine. (Since pressure remains in the cylinder, it eventually gets to a point of having a better mechanical advantage, but by then the pressure in the cylinder has dropped quite a bit due to the piston lowering and the cooling system effectiveness.) A large amount of wasteful frictional and cooling system heating is the result of this inherent characteristic of automotive engines, and the engine bearings take a serious beating. The engine then needs a variety of systems (lubrication system, cooling system, etc) to then discard all this heat energy that is wasted.