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Background to the TS3
In 1954, after a few years of development, Rootes Group released the TS3 two-stroke diesel engine. The TS3 was initially designed by Rootes Power Units Chief Engineer Eric W Coy (and under him, designers Bennett and Mileluski) at the Humber plant (Stoke-Aldermore) in 1948. It was designed solely to meet Rootes production planning requirements for an underfloor 105hp diesel engine for the new forward control Commer range of heavy trucks.
The TS3 was a radical departure in engine design for a company like Rootes to take in 1948. A two-cylinder prototype was built and tested (see Don Kitchen's story in the Commer Men section) with the intention of putting this in the heavier bonneted Superpoise series and for industrial use, but it was decided not to pursue with this design, possible due to vibration problems. Two TS3s were initially built, one on a test bed and one in a truck. The rocker design caused considerable problems with many failing before this was overcome. One on occasion, the test truck broke down out on the road. As this truck with its special new engine could not be left out on the road, Eric Coy went out and towed it back with a Humber Super Snipe! Eventually they got the design of the rocker right, and it was so good, it broke the vibration test machine at the Rootes Group's Ryton testing facility. The men from Tillings Stevens were not very popular with the rest of the Group! As far as is known, the vibration tester was never rebuilt.
The engine was a direct injection, high speed diesel engine with three horizontal cylinders, each containing two pistons. Each cylinder had specially designed ports to control the inlet of air and outlet of the exhaust which are controlled by the pistons. The pistons which control the inlet ports are known as the air pistons (left-hand side of the engine) and the pistons which control the exhaust ports are the exhaust pistons.
The pistons are connected through short conrods to rockers mounted on a common shaft on either side. The rockers are, in turn, connected through short rods to a single crankshaft.
A Roots - type scavenge blower made by Wade Engineering of Birmingham is mounted to the front of the engine and is driven from the timing gear train at the rear of the engine by way of a long slim shaft to supply air under pressure into the cylinder which helps in the scavenging of the exhaust gases. Note that this blower is not a true supercharger.
The Engine Cycles
Step 1
The pistons are commencing their compression stroke. The exhaust piston has a slight lead over the air piston to ensure the exhaust ports are closed, while air is still entering through the air ports. The design of the ports causes the air to swirl as it enters the cylinder to aid compression.
Step 2
The pistons are now at inner dead centre. Shortly before the pistons reach this position, an atomised spray of diesel is injected into the cylinder, and this is ignited by the intense heat generated by the compression of the air in the cylinder. The resulting pressure forces the pistons apart to provide the power stroke.
Step 3
As the pistons approach outer dead centre, the exhaust port opens first and the exhaust gases are released.
Step 4
Further outward movement of the pistons opens the air ports and air from the blower swirls into the cylinder towards the exhaust ports which scavengers the exhaust gases. This continues until the pistons have passed through outer dead centre and start another compression stroke when the cycle is repeated.
TS3 Sound Files / Animation
Note - TS3s usually started on the touch of the button.
The owner of this TS3 likes to hold the fuel stop button
up until oil pressure registers hence the slight reluctance to start
Turn your speakers up loud!
TS3 motor General Data - click the MORE button for more info on this amazing motor...
Click the Play button to watch a TS3 animation
- animation pages courtesy Mark Erskine
Click the Play button to watch the movie
To the right is a small movie of a cutaway TS3 motor. You will need Quicktime to see this movie. There are links to download this software on the Movies page.
With thanks to Ian Ridd and the Bill Richardson collection