Kelvin Sleeve Valve Engines

General Description

The Kelvin petrol engine operated on a 4 cycle principle and were renowned for their silent motion. The Daimler version, having 2 sleeves earned the name "Silent Knight" from its designer.


Very quiet, therefore ideal for use in boats.
No poppet valves, tappet noise was eliminated.


 Although generally very successful, this type of engine had a high oil consumption and breakage's in the sleeve driving mechanism were not uncommon.

Description Of Sleeve Valve Mechanism

The sleeve valve consists of a thin cast iron cylinder encircling the piston and working between it and the cylinder proper. It silently performs the functions for which valve, cams and tappets are usually employed. The following elements are employed to achieve the movement described.
1.    The Sleeves:

    These are operated in pairs by a disc crank working at half engine speed and driven by a chain from the crank shaft. The disk cranks move the sleeves up and down as well as giving a limited side movement in the form of an ellipse. A ball, fitted to the base ring of the sleeve provides the required movement.

2.    Cylinder Design:

   In each cylinder there are inlet and exhaust ports which at the correct moment register with ports in the sleeve, allowing gasses to enter and escape. As the piston moves downwards on the induction stroke the inlet port in the  sleeve travels over the port in the cylinder wall allowing the mixture to enter the  cylinder. As the piston reaches the bottom of its stroke, the sleeve has started to move upward, the port now passing behind the ring in the head. The piston and sleeve continue to move upwards until at the highest point ignition takes place. The piston now moved downwards on the power stroke and as it reaches the bottom of its stroke the exhaust port in the sleeve moves over the port in the cylinder wall allowing the exhaust gasses to escape, meanwhile the inlet port in the sleeve has passed between the ports in the cylinder wall keeping the inlet ports closed.

3. Cylinder Head:

   The  cylinder head can be of a uniform shape, since at top dead centre of the ignition stroke we have conditions where the cylinder is surrounded by solid wall, no ports being exposed. At top dead centre on the induction stroke we have conditions where the exhaust port is closing and the inlet port is opening. As the piston moves downwards the exhaust ports, due to the rotary movement of the sleeve, pass between the ports in the cylinder covering the exhaust. The sleeve never comes to rest as it is always moving in a circular path.

Further Information

Historic Manual:

"Kelvin Sleeve Valve Engines" - running and repairing of models A2 and A4

Parts Catalogue:

Bergius Company Ltd.

Spares List:

Bergius Company Ltd.

Patent Specification:

H.M.S.O. No. 194, 512 (1922) "Improvements in Single - Sleeve Valve mechanism for Internal Combustion  engines".