Unlike the Italian Ettore Bugatti or the native from Vratislavice nad Nisou Ferdinand Porsche, the name of the American Knight isn’t that well known. Definitely he is worth the attention, because his sleeve valve engine capitalised from his invention was used by number of the prestigious car brands at the first third of the 20th Century: from British Daimler through the German Mercedes or the French Voisin up to the Czech RAF at the Laurin & Klement.
Who would have said today, that the sleeve valve preceded developmentally the poppet valvetrain. The father of the high-speed internal combustion engine Gottlieb Daimler after the addition of the complex mechanism left the solution inspired by the steam engine. The high-quality mineral oil was not available at the market at that time. As the situation in the mechanical oil field was improving, the idea of the quiet and precise sleeve valve returned. The problems were facing at the time, such as the deterioration of the material in the valve seats, valve lifetime, bursting of their springs and unpleasant noise. The non-detachable cylinder head with SV, IOE, and other valverains didn’t provide sufficiently effective emptying or filling the cylinder. Charles Yale Knight, natives from Indiana who had originally been an agricultural newspaper “Dairy Produce” publisher, who got in 1930 tricycle Knox capped with noisy valves, was inspired by the steam system powering his father’s cutter saw. The development of the silent engine for over five years supposed to cost him around 150 000 dollars and the first four-cylinder ”Silent Knight” which debuted at the Chicago Auto Show in 1906 was sold for 3500 dollars. However, Knight managed to sell a mere thirty-eight engines in the USA during the first there years.
In the following period several US manufacturers including Pierce-Arrow tried the news. Better efficiency of the Knight engine was proved at the speed of 30 miles per hour (48 km/h), but the excessive oil consumption was interfered. Thanks to the interest of the already mentioned British premium brand Daimler, which have been using the proprietary solutions since 1908, made the Knight Units hole in the world. Challenging and vital Daimler Knight tests, provided by the club RAC at the Brooklands circuit, were so convincing that after the release the Daimlers share price soared from the 0,85 to 18,75 pounds! It’s important to say, that British constructers significantly improved the practical applicability of the American structure.
The US automakers (most of the Knights were made by Willys) and also the continental competition Daimler like French Panhard-Levassor, Belgium Minerva, German Mercedes and Czech company in Liberec RAF showed the interest in buying the licence. If we exclude the aircraft engine, than the Daimler Double six (6.5 V12, 1932) had the largest power unit of the structure.
How does the engine Knight works?
While the piston goes down from the top dead center, the sleeve valves move in relation to one another, which makes the intake port fully open at a much faster speed. The piston is then at the bottom dead center and both sleeve valves move upwards. However, the movement of the inner sleeve valve is quicker, so fresh fuel mixture could fill the combustion chamber more effectively than in poppet valve engines of that time. Historical sources indicate greater effectiveness in the cylinders, while reducing ignition temperatures. The quiet operation of Knight engines was the result of the limited friction of perfectly – machined parts and of the fact that there were no direct impacts on metal surfaces, which was the case in the operation of the valve and its seat. The high torque achieved at low rpm must not be forgotten either when listing the pros of the sleeve valvetrian.
In the 30s started to lose the breath and considerable inertia valves compared with the valves had resisted increasing engine speed. Initial complains relating to significant smoke was in the past and the seventeen ride during which the special Voisin in September 1930 without any failure covered a great deal of 48 901 km and proved the viability of Knights solutions. His Swan song was heard in the second half of the 30th.