A method of avoiding cams, and with it all cam troubles, is the use of a sliding sleeve in place of a valve, slots in the sleeve corresponding to the usual valve openings, both as to area and timing. The sleeves may be operated by means of eccentrics, by various lever motions, or by a direct drive by means of a gear.

A Jig for Slotting Valve Stems Which Can Be Made for a Fow Cents.

Fig. 32. A Jig for Slotting Valve Stems Which Can Be Made for a Fow Cents.

Fig. 33. Section through Ledru (French)Cam less Engine. The Rotary Gear - Driven Sleeve Displaces All Cams.

Gear Control

An example of the application of a worm and gear for this purpose to a French two-cycle engine is shown in Fig. 33, although there is nothing in its construction which would prevent its use on the more usual four-cycle engine.

In this figure, P is the usual crankshaft, Q the large end of the connecting rod K, while A is the piston and It the crank case, no one of these differing from those in other engines. On the crankshaft there is a large gear F, which drives a smaller gear E, located on a longitudinal shaft above and outside of the crank case. On this shaft is located a worm gear D, which meshes with a worm C formed integral with the sleeve surrounding the piston B. Aside from this worm gear, the sleeve is perfectly cylindrical, being open at both ends. It is placed outside of the piston, between that and the cylinder walls. At its upper end, it has a number of ports or slots cut through it, which are correctly located vertically to register or coincide with the port openings in the cylinder walls, when the sleeve is rotated. At H is seen one of these - the exhaust, while 90 degrees around from it, and hence invisible in this figure, is a similar port for the inlet. As . the crankshaft rotates, the side shaft carrying the worm is constrained to turn also. This turns the worm which rotates the worm wheel and, with it, the sleeve. Thus the openings in the sleeve are brought around to the proper openings in the cylinder and the combustion chamber is supplied with fresh gas, the burned gases being carried away at the correct time in the cycle of operations.

Fig. 34. Osborn Valve Moduli without Cams.

With a motor of this sort, the greatest question is that of lubrication. The manner in which it is effected in this case is by means of the large wide spiral grooves shown at 00, and the smaller circular grooves at the upper end M. This problem is also rendered more easy of solution by the machining of the sleeve, as during this operation much metal is cut away along the sides so that the sleeve does not bear against the cylinder walls along its whole length but only for a short length at the top and a still shorter length at the bottom.

Eccentric And Lever Control

The same result is accomplished by the use of a combination of eccentrics and levers, as is indicated in Fig. 34, showing the idea of a New York inventor, Osborn. This scheme places upon the usual cam gear an eccentric pin, upon which is located an eccentric rod or lever A. The latter is pivoted at its lower end to a pin B, which pin is a part of a sliding member C, carrying upon its upper part a piston rod E. This slide reciprocates, according to the impulse imparted to it by the eccentric A, being guided by the slides D, which are fixed to the side of the crank case.

Upon the upper end of the piston rod E is fixed a piston F, and slidably mounted around the whole is another piston valve J. The piston F is always moved by the rod, while the valve J is only moved upward by the collar at I, its downward motion being produced by a spring, not shown. G is the combustion chamber into which it is desired to lead the fuel mixture, and out of which the exhaust gases must afterward be taken, through the exhaust pipe H. K is the inlet pipe, LL are the inlet ports, and M is the exhaust port. Unfortunately, this drawing shows the piston at the top of its movement, which would be more clear were it at the bottom. On the down stroke of the inner piston, moved positively by the eccentric, the exhaust gases rush down and out. On the same stroke, the inflowing gas fills the passage around the outside of the piston, so that when the exhaust stroke is completed, and the piston has risen so as to uncover the lower edge of the port through the walls 0, the gases are free to rush in, impelled by the suction of the motor piston. In the meantime, the rising outside sleeve has covered the exhaust port M, so that none of the mixture may escape to the outside air.

Knight Sleeve Valves

In the last few years, tremendous progress has been made here and abroad with the Knight motor, named after its Chicago inventor. In many important factories this has displaced those with the poppet form of valve. In this, a regular four-cylinder four-cycle engine, the valves consist of a pair of concentric sleeves, openings in the two performing the requisite functions of valves in the proper order. These sleeves, as Fig. 35 shows, are actuated from a regular camshaft - running at half the crankshaft speed and driven by a silent chain - by means of a series of eccentrics and connecting rods. In the figure, A is the inner and longer sleeve carrying at its lower end the groove or projection C, around and into which the collar actuating the sleeve is fixed. This collar is attached to the eccentric rod E, which is driven by the eccentric shaft shown. The collar D performs a similar function for the outer sleeve B.

Fig. 35. Willys-Knight Engine in Which Eccentries and Sliding Sleeves Replace.

Table I. Royal Automobile Club's Committee Report On Knight Engine

Motor horsepower - R. A. C.......

38.4

22.85

Bore and Stroke.......................................

124 by 130

96 by 130

Minimum horsepower allowed.....

50.8

35.3

Speed on bench test..............

1200 r.p.m

1400 r.p.m.

Car weight on track...............................................

3805 1b.

3332.5 lb.

Car weight on road..............

4085 lb.

3612 5 lb.

Duration of bench test............................

134 hours 15 min.

132 hours 58 min.

Penalized stops........................................

None

None

Non-penalized stops................................

Five - 116 min.

Two - 17 min.

Light load periods...................................

19 min.

41 min.

Average horsepower.....................................

54.3

38.83

Final bench test......................................

5 hours 15 min.

5 hours 2 min.

Penalized stops.......................................

None

None

Light load periods.................................

15 min.

1 min.

Average horsepower...............................

57.25

38.96

Mileage on track.....................................

1930.5

1914.1

Mileage on road......................................

229

229

Total time on track................................

45 hours 32 min.

45 hours 42 min.

Average track speed...............................

42.4 m. p. h.

41.8 m. p. h.

Fuel per brake horsepower per hour

First bench........... .679 pt.

.739 pt.

test........ .613 lb.

.668 1b.

Final bench.......... . 599 pt.

.749 pt.

test............................. .541lb

.677 1b.

Car miles per gallon................................

On track............. 20.57

22.44

On road............. 19.48

19.48

Top miles per gallon................................

On track............... 34.94

33.37

On road............. 35.97

31.19

At the upper ends of both sleeves, slots 0 are cut through. These slots are so sized and located as to be brought into correct relations to one another and to the cylinder ports, exhaust at H and inlet at I, in the course of the stroke.

It might be thought that the sliding sleeves would eat up more power in internal friction than would be gained, but a very severe and especially thorough test of an engine of this type, made by the Royal Automobile Club of England, an unbiased body, proved that for its size, the power output was greater than that of many engines of the regulation type. Moreover, the amount of lubricating oil was small.

The results of the test are shown in Table I. After the test was concluded, both of the sleeves, Fig. 36, were found to show still the original marks of the lathe tool. This proved conclusively that the principle of this type was right, for the tests were equivalent to an ordinary season's running.

Referring to Fig. 36, the slots which serve as valve ports are at G. The longer sleeve A is the inner one. At the bases of the sleeves are the collars and pins D by which the connecting rods are attached. The surfaces of the valves are grooved at J to produce proper distribution of oil.

Fig. 36. Sleeves Which Replaced Valves on Knight Engine, altar 137.Hour Bench Test and 2200 Miles on the Road.

The Knight type of motor has been adopted by a number of well-known firms in America such as the Stearns, Willys, F. It. P., Brewster, and Moline Companies. These engines are noted for their silent running and for their efficiency. The Moline-Knight motor was in January, 1914, subjected to a severe continuous-run test of 337 hours under the auspices of the A. C. A. authorities. During this time the motor developed an average of 38.3 brake horsepower. For the 337th hour the throttle was opened and the motor developed a higher speed and a brake horsepower of 53. The test gives abundant evidence of the endurance and reliability of the sleeve-valve type of motor and of the sterling qualities of the product of the American automobile manufacturers. After the test the motor parts showed no particular evidence of wear.

In addition to the four-cylinder forms just mentioned, the Knight type of motor is also made as a six, and more recently, as a V-type eight. In these forms, the basic principle of sliding sleeves and their method of operation and timing is not changed.

Originally, the Knight motor was installed only in the highest class cars. The firms in Europe which took it up ranked among the very first - notably the Daimler, Panhard, Minerva, etc. - but in this country it has made little progress among the better cars, and now it is assuming the rank of a low and medium priced motor, being available for about $1,000, and as an eight for approximately $2,000.