You may be interested in the FUELCAT link below (see reference to Russian front 1942). It shows how the performance of lower grade fuel can be improved and states the example of Hurricane engines that needed 100 Octane fuel performance in Russia in 1942. This is obviously PR information for the company, but it points to the availability of a historic stop gap solution, if or when supplies of 100 Octane were ever in short supply. I would suspect that things were always changing, but if 100 Octane fuel was ever in short supply, perhaps for short periods only, they had the FUELCAT technology.
Henry Broquet's Catalyst - born in Desperate Times
Henry Broquet's fuel catalyst is not just another short-lived magic gadget that claims to work unexplained wonders with car engines. It was developed, tried and proved in the hardest arena possible - the Russian front in 1942.
Rolls-Royce motors meet Lada Fuel!
When Britain sent Hurricane fighters to Russia in 1941, their Merlin XX engines needed the special 100 octane petrol developed for the RAF. Although a supply was shipped there to startwith, the Russians themselves were unable to produce any more. Their fuel was not only lower grade but very variable in quality. Henry Broquet, a British technician, collaborated with them and came up with the tin alloy catalyst, a workable answer that enabled the Merlins to run on lower grade petrol satisfactorily. Why was the grade of fuel so critical? After all, car engines can be detuned to run on cooking petrol by retarding their ignition or fitting thicker head gaskets. You simply could not do that with a thoroughbred Rolls-Royce aero-engine.
The power output of a piston engine depends upon firstly the revolutions per minute (rpm) and secondly the pressure developed in the cylinders. Friction and mechanical stress limit the rpm, but fuel is one of the main factors limiting the attainable power. This is mainly due to the problem of detonation. If the fuel/air mixture is compressed too much, it may not burn evenly but explode suddenly. This gives a very high peak pressure and a sharp blow on the piston instead of a steady push. The energy from the fuel does no useful work but is wasted as heat. Severe or prolonged detonation can blow holes in pistons, burn out exhaust valves and even knock off cylinder heads. Car drivers can hear the characteristic pinking sound caused by the shock waves hitting the cylinder walls.
Petrol's resistance to detonation is given by its Octane Rating. This is the percentage of iso-octane (full chemical name 2,2,4 trimethyl pentane)contained in a mixture of iso-octane with normal heptane that reproduces the same knock characteristics as the petrol when tested under standard conditions. One of the ways to increase octane rating is to dope the fuel with tetra-ethyl lead. What this does is to steady the rate of combustion and inhibit the sudden temperature rise ahead of the flame front that triggers the explosive ignition. A drawback is that lead deposits tend to build upon the spark plugs so ethylene dibromide is often added, to combine with the lead and take some of it out in the exhaust.
Pre-ignition and Plug Fouling
Another problem with mediocre fuel is that it may have poorly combustible components that have not been refined out, and they leave unburned deposits on the cylinder head and valves. These impair cooling and may get so hot that they act like diesel glow-plugs, igniting the mixture before the spark plugs fire, too early before top dead centre. The effect of this pre-ignition is similar to detonation and equally damaging to the engine. Characteristically a hot engine will "run-on" after the ignition is cut, as though it was a diesel. (Inefficient pre-war side-valve engines used to need decarbonising every ten thousand miles or so because they built up these unburned deposits.)
Lead is Dead, Long Live Tin!
Big European and American oil companies saw no need to take up this development. They had invested a lot in tetra-ethyl lead and had no incentive to try something completely different. But lead is to be banned from petrol by the year 2000. Millions of motorists and boat owners with engines designed for 4-Star are going to have problems. True, they can buy expensive "super unleaded" instead, which is supposed to equal 4-Star. However, this has all sorts of other detonation suppressing additives instead of the lead. Some of these additives themselves are not very nice. Furthermore, they still leave the problem that some designs also rely on the lead to protect valve seats from erosion and stop valves from sticking.
Henry Broquet's well-proven tin catalyst is a better answer than tetra-ethyl lead anyway, improving the fuel before it goes into the engine so that combustion is more efficient. This reduces deposits on the cylinder head and valves, and also the amount of waste heat going into the exhaust. As a result exhaust valves and their seats are cooler and do not need a protective coating of lead. Finally, more efficient combustion means less exhaust emissions.
If anyone needs proof that it works, they need look no farther than those hard-pressed Merlins in Russia!
The above history, product information and FAQ's have been adapted from FUELCAT promotional literature.