Pioneer Sleeve Valve Engine 1 (original) (raw)
Pioneer Sleeve Valve Engine 1
Pioneer Sleeve Valve Aero-Engine
by Jerry Wells
Published 3 Oct 2006
The Origins of the Sleeve Valve
The sleeve valve story starts in the early 1900s when Chicago based engineer Charles Yale Knight (1868 - 1940) began experimenting with cylindrical valves in an effort to circumvent the problems of weak valve springs and burnt poppet valves that were plaguing the automobile engines of the time.
With the double-sleeve valve system (see fig. 1, top right) Knight had a viable alternative to offer the auto fraternity and the system was widely adopted in both the U.S. and Europe.
Whether Burt and McCollum were inspired by the Knight invention is hard to say but just as the "Silent Knights" were becoming numerous on the roads, the single-sleeve breakthrough was made.
Fig. 3. Prototype Burt Sleeve-Valve Engine |
The sleeve valve as envisaged by Burt is clearly depicted in Letters Patent document No GB 190,918,140 dated 6 August, 1909. Burt describes the mechanism as, "This invention which relates to internal combustion engines and particularly to that class of such engines as are of the high-speed type, has for its object, by means of the special construction of the engine cylinder and of the construction and arrangement of the working parts within said cylinder, the provision of a simple and efficient engine which is practically noiseless in its action." However, at the end of the patent, he says, "We are aware that in connection with internal combustion engines, it has already been proposed to employ a cylindrical valve and give the same both oscillatory and reciprocating movements in order to control the inlet and exhaust and we, therefore, do not broadly claim such an arrangement." This may be some recognition of the work of James McCollum whose name does not appear on the patent document at all.
To move the sleeve valve in his prototype engines, Burt attached two lugs to the basal part of the sleeve. A pin was placed between the lugs and secured to them by a bolt. The pin, at its other end, made a sliding fit into a rotatable drum; the pin hole being drilled eccentrically so that when rotated by the chain drive from the crankshaft the sleeve moved both vertically and in a rotational sense (see fig. 3). It was some years before the familiar crank-and-ball joint drive was adopted.
This arrangement was suitable for single-cylinder prototypes but for multi-cylinder engines the drive had to be from the side so a shaft running parallel to the cylinder bank and driven at half speed from the front or rear of the crankshaft was used. Worm gears on the shaft meshed with those on the outside of the drums. This type of drive for the sleeves was used on the production Argyll cars and on the prototype 120 hp Argyll aero-engine. The lower left panel of figure 1 is a transverse section of the proposed Continental 6. The sleeve drive here is similar to that used in the Argyll autos but is slightly more advanced in that the connection at the sleeve uses a ball joint.
James Harry Keighly McCollum was a resident of Toronto, Canada and he describes himself as a "mechanical engineer". His idea of how a sleeve valve engine should work is detailed in Patent No GB 190914,629 which was filed on the 22 June, 1909 just two months before that of Peter Burt. McCollum describes his invention as follows, "The valve gear employed is of the type which has both lateral and reciprocatory movements in order to control the inlet and exhaust and according to the present invention, such valve is arranged substantially coaxial with the piston. A further feature of the invention is that such valve is provided with two sets of ports, one set adapted to register with a set of inlet ports in the cylinder and the other set adapted to register with a separate set of exhaust ports in the cylinder."
Although, in principle, the McCollum valve operates in the same way as the Burt sleeve, there are differences. In the Peter Burt sleeve valve engine, the sleeve is an open-ended cylinder which fits between the piston and the cylinder wall. Thus it is subject to considerable pressure and temperature during the operation of the engine. The sleeve is controlled from the inside of the crankcase and from the base of the cylinders.
In the case of the McCollum variation, the sleeve is a cylinder closed at the top and fitted completely exterior to the cylinder, i.e., it fits over the cylinder outside of the inlet and exhaust ports (and the water jacket as well) so it only gets a blast from the combustion process at the spot where the sleeve valve shuts off the exhaust ports.
To operate the valve, the McCollum cylinder is fitted with normal pushrods and rockers, except that the "inlet" pushrod and rocker causes the sleeve to go up and down while the "exhaust" apparatus causes the sleeve to rotate. Thus, all control of the sleeve is from the top of the cylinder. This arrangement would, of course, produce all the noise and rattling that normally emanates from such a system.
What a study of the respective patents of McCollum and Burt shows is that all the automobile and aero-engine applications of the so called Burt-McCollum system are much more "Burt" than they are McCollum!
Any records of the McCollum engines being built and tested seem to be lost in the annals of time. However, the same does not hold true for the Argyll/Burt 6 cylinder aero-motor. At least two of these engines were built and although they never got airborne or tested in combat, they did get an opportunity to display their wares and to be compared with contemporary engines by way of the 1914 Farnborough trials.
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