The Concept IC Engine
The second really innovative engine design described in these pages, is the Concept IC Engine , which utilises a revolutionary new design , to completely transform the conventional IC engine . The great advantage of this design is that existing IC engines can be modified to run as Concept IC engines at minimum cost while at the same time increasing efficiency by as much as 200% and also reducing fuel emissions to zero. This may sound far fetched but as you will see , if you continue to read these pages , a detailed and well documented rationale is given as to why this engine can and will work. In fact anyone who can provide a logical and verifiable refutation of the Concept IC engine shall receive from me a most abject and humble letter of apology.
Studies have shown , and this may easily be verified from The Colorado State University Engine Web Site , a link to which is provided , that IC engines lose 42% of their energy to exhaust and 28% of their energy to the cooling system. With more than 500 million cars world wide (not counting buses , trains , construction and military transport ) and with this number constantly increasing there is an urgent need for better , cleaner , more efficient engines. The Concept IC engine provides a low cost and highly effective solution to solving all these problems.
Introducing the Concept IC engine:
Automotive engineering has seen a spate of innovations in the past decade , MV's (Multiple valve's ) , DOHC's (Double overhead cams ) , MPFI (Multi-port fuel injection) and DFI (Direct fuel injection ) which , when combined with stronger and lighter carbon composites and metal alloys , are rapidly bringing reciprocating internal combustion engine technology, as we know it , to a point where the full potential of the engine has almost been realised.
Extensive coverage in magazines and other media , have reported on almost every aspect of the working of these innovations and the advantages their implementation has resulted in , such as better fuel economy , more power and a cleaner engine. What is less widely known is the fact that in spite of the huge amounts of money and man hours spent on researching and implementing these products the overall efficiency of the RI engine has been increased by a mere 5%. The engine is now less than 25% efficient as compared to an original efficiency of less than 20%. The expected improvement in performance has fallen far below expectations. What is the reason for this ?
Real contribution made by recent innovations:-
The real contribution that innovations such as DOHC's, MV's , MPFI and DFI have made to RI engine design has been in high-lighting and identifying what is not wrong with the engine. An increase in efficiency of a mere 5 % , or an overall efficiency of less than 25 % even after the implementation of the innovations under discussion , has shown that it is not basically valve over-lap , valve lead , valve lag , linear to rotary conversion , or any of the traditionally quoted reasons ,which is responsible for the poor performance of the engine . To find the underlying causes behind the inefficiency of the RI engine , it is necessary , therefore , to look elsewhere.
Efficiency of the IC engine:-
IC engines lose 42% of their energy to exhaust and 28% of their energy to the cooling system. Therefore the true explanation for the poor performance of the engine would seem to lie in inefficient use of energy and loss of energy through heat transfer. The loss incurred through inefficient use of energy is easily understood , compressed fuel and air is ignited and is then used to propel the piston down the cylinder with explosive force for a distance of just a few inches after which all further energy developed by the fuel is lost and in fact becomes a liability since the piston has to reverse direction , a process which is inhibited by the pressure of trapped gases on the piston head. The reason that energy loss to heat transfer has been tolerated , and even welcomed by engineers , is a little more involved and will be referred to later on in the article.
Notwithstanding the improvements made to the RI engine we have to ask ourselves , and this is the million dollar question , is this really the limit of performance of the reciprocating internal combustion engine, does this mark the end of the road for this more than 200 year old concept , some entrepreneurs seem to think not , they have come up with the idea of a concept IC engine.
Comparison of the IC engine with a gun:-
The comparison between a gun and the reciprocating internal combustion engine is appropriate , the piston can be likened to a bullet or projectile, the cylinder to a barrel and the fuel - air,mixture to the explosive propellant.The theory underlying concept IC engine technology has been established,to put it simply,on the concept of the recoiless gun. The reduction of recoil in the recoilless gun is due to the fact that the mass/velocity of the escaping gases is engineered to equal or approximate the mass/velocity of the projectile , thereby canceling each other out , the velocity of the escaping gases can be increased by use of a venturi or nozzle. Recoilless Guns (Click to link to article on recoilless guns.)While it is true that there is a certain reduction in the muzzle velocity of a recoilless gun , when compared to a conventional cannon of similar caliber , it should be understood that this reduction is dependent on several factors , the most important of which is the length of the barrel. This is because muzzle velocity is contingent on the velocity of the propellant gases behind the projectile and the pressure generated , this is significant only in a gun with an appreciable barrel length. The fact that most engines have cylinders of extremely short length ( the throw of the piston in a conventional engine is only four to five inches on average) makes it possible to seriously consider applying recoilless technology to the reciprocating internal combustion engine.
In a conventional reciprocating internal combustion engine, the piston is forced down the cylinder by the expanding gases and the pressure they generate. As soon as the piston reaches BDC however , the velocity of the gases comes down to zero , and can perform no further useful work , and the pressure becomes a liability , since the movement of the piston has now to be reversed .
Working of the Concept IC engine:-
By contrast the concept internal combustion engine incorporates a slide door or sleeve type valve which completely opens, (providing unrestricted passage to the exhaust gases ) onto a nozzle and is substituted for the regular type of exhaust valve which only partially opens , this exhaust valve is opened after ignition of the fuel- air mixture , resulting in the explosive expulsion of gases through the nozzle , the velocity of these escaping gases result in the piston being pushed down the cylinder in an equal and opposite reaction.. (This is in conformance with Newton's third law which states that for every action there is an equal and opposite reaction. In the case in point it is the velocity of the escaping gases which constitute the action and the force exerted on the piston head the reaction.) This is due to the fact that (a) the exhaust valve is opened only after ignition has taken place , meaning that maximum pressure has already been achieved within the cylinder and (b) the velocity of the escaping gases push the piston down the cylinder with approximately the same force as they would exert if the valves were closed and the gases expanded in a confined space as happens in a conventional engine, the length of the cylinder being too short to appreciably affect the velocity with which the piston is forced down the cylinder .
The most significant improvement offered by the Concept IC Engine:-
The most significant improvement that the concept IC engine has over conventional RI engines is that the explosive ejection of hot exhaust gases can be used to efficiently power a turbine which in turn can run the auxiliary devices which are at present powered by the main engine, such as the turbo-charger, How Turbo Chargers work. (See link at bottom of page to article on Turbochargers.) the dynamo, the oil-pump, water pump ,cooling system etc., The power output from the turbine can also be harnessed to augment the main power unit output by being linked to a generator which would then run electric motors directly linked to the wheels , if the main piston unit is also linked to a generator the result would be an almost soundless , and very efficient power plant run on the lines of a diesel electric train power plant. The concept IC engine therefore , in effect has two engines , the primary or piston engine and the secondary or turbine engine, which are powered using the same amount of fuel needed to run a conventional reciprocating internal combustion engine. Therefore the concept IC engine should in theory , be more effective than present day reciprocating internal combustion engine designs, and will make use of a lot of the energy which is at present wasted. In conventional engines 42% of the energy generated is lost to exhaust , and 28% to the cooling system, by using energy which would otherwise be wasted , and improving on it , the recoilless engine, could be a 100% more efficient than present day conventional engines. In multi-cylinder recoilless engines , the secondary turbine unit might in fact function more efficiently than the primary piston unit, because of the provision of a continuous flow of hot exhaust gases at velocity to power the turbine . The Turbine Engine for cars
Power stroke in an IC engine examined:-
If we examine in detail , the power stroke in a four stroke cycle of the RI engine the concept of a recoilless engine , and why it can work , becomes clearer., We find that the power stroke , has to start at a minimum of 20 degrees before TDC , or before valve overlap (the period when both exhaust and intake valves are kept simultaneously open) would be initiated and that , valve lead or the opening of the exhaust valve in order to relieve pressure on the piston head has to be initiated in the same stroke at a minimum of 50 degrees before BDC , if this were not the case the piston head would be damaged or cracked due to the conflicting stresses. Thus taking the full stroke to be 180 degrees , we find that power is available for roughly 110 degrees.
In a concept IC engine , the exhaust valve would be fully opened after ignition and conventional power (i.e with valves closed ) would be available for 50 to 60 degrees as compared to the 110 degrees of the conventional engine and recoilless energy would account for completion of the remaining part of the stroke, the difference to final power output would therefore be negligible.
Valve system in an conventional IC Engine:-
It would be appropriate before proceeding further , to examine the effect of the conventional valve system on exhaust gas velocities and temperature. Conventional poppet type valves are by design meant to open the exhaust port only partially and depend upon the pressure created by the movement of the piston up the cylinder to force the exhaust gases out through the small gap available . When valve lead takes place at 50 degrees before BDC during the power stroke of a conventional engine , the pressure of the exhaust gases on the piston head is partially released , yet the design of the exhaust valve is such that much of the heat and therefore energy of the exhaust gases is lost trying to force their way past the exhaust valve and the longer time that the exhaust gases have to stay trapped in the cylinder before the actual exhaust stroke takes place means that much of the heat in the exhaust gases is transferred to the engine block thereby considerably reducing the total energy available when the gases finally make it out through the exhaust port. The cam-shaft is designed to fully open the exhaust valve for a very brief period at BDC , during valve lead ( i.e., exhaust valve opens 50 degrees before the exhaust stroke) and during the greater part of the exhaust stroke , the exhaust valve is only minimally open giving rise to the loss to heat transfer as discussed above. At the same time this partial release of gases through the exhaust port results in a greater load being placed on the fly-wheel since resistance to its movement , and therefore to the movement of the piston ,is still present in the form of pressure exerted by partially trapped gases on the piston head.. While this may have been desirable and even welcomed at one time , since it results in a cooler exhaust , and also results in
better and easier sealing of the cylinder because of the small distance that the valve has to travel , it also means that much of the energy available in the exhaust gases is lost to heat transfer to the engine block and the rest of it being lost through the exhaust without being utilised. It is this factor , more than anything else , that is central to the relative inefficiency of the present day RI engine.
By contrast the exhaust valve in the concept IC engine is activated almost immediately after ignition, during this very short time , the pressure would have already peaked in the cylinder, thus the exhaust gases would be used for powering of the turbine when they have maximum .energy and velocity , further the reaction produced by these escaping gases on the piston head would aid in the transfer of energy to the fly-wheel and the smooth return of the piston for the next stroke because the pressure of partially trapped gases on the cylinder head , as exists in the working of a conventional engine , is absent. In practical terms it would mean , as has already been explained ,that the exhaust valve is opened at 80 to 90 degrees before BDC instead of at 50 degrees as occurs in a conventional engine , thus conventional power (with valves closed ) would be available for 50 to 60 degrees of the stroke and recoilless energy for the remainder of the stroke , one cannot see this making an appreciable difference to the overall power exerted on the piston.. The exhaust valve in a concept IC engine is designed to open as fully as possible and to offer an unrestricted passage to the exhaust gases. This has the effect of (a) reducing load on the fly-wheel (b) extracting ,when coupled to a turbine unit ,the maximum possible energy from the heat generated by the combustion of fuel.