How it Works
A conventional internal combustion piston engine is inefficient because the linear movement of a piston when converted to rotational movement of a crankshaft is effective only when the piston is halfway between top dead centre (TDC) and bottom dead centre (BDC). Because of the fixed geometry, the ignition and exhaust strokes are of equal lengths and the compression ratio is effectively fixed.
Maximum efficiency is obtainable only where the compression stroke is shorter than the power stroke (Atkinson cycle), where the compression ratio can be tuned for engine loads, speeds, fuel type and where the valve timing can be varied to reduce pumping losses. In a compression ignition engine significant gains can be made where the compression stroke is also shorter in time than the power stroke which results in less heat being transferred to the engine and improved compression ignition control, particularly in two stroke diesel engines. Internal combustion engines exist which exploit the "Atkinson cycle", have variable compression ratio and variable valve timing. However, these engines are costly to produce due to the complex nature of the internal mechanisms/mechatronics required, and as yet no commercial engine exists having all of the above.
The innovative and novel feature of the TCK engine design that represents a significant technological advance is a crankless mechanism that replaces the conventional crankshaft in a piston engine. A fixed connecting rod extends from the piston and carries a pair of spaced apart rollers where one engages a primary cam and the second engages a secondary cam, the primary and secondary cams being rigidly affixed to a common output shaft. The position of the piston depends on the rotational orientation of the output shaft or vice-versa. By replacing the crankshaft of a conventional internal combustion engine with the cams and rollers, it becomes possible to tailor the conversion of reciprocating movement of the piston into rotational movement of the output shaft, or vice-versa, by the careful selection of cam geometry. The primary cam is used for converting linear movement of the piston into rotational movement of the output shaft, whereas the secondary cam is used for converting rotational movement of the output shaft into linear movement of the piston.