Ignition unit in the ignition system of an internal combustion engine

A cartridge unit included in an ignition system of an internal combustion engine and connectible to a plurality of spark plugs in the engine, said cartridge unit comprising an upper part securable to adjacent engine parts, a number of finger-like connection casings detachably mounted to the upper part and extending from the upper part, one casing, for each spark plug, said connection casings and upper part, when attached to each other, forming together an outer shell with an essentially closed inner space encapsulating a high tension block comprising at least one ignition coil for generating ignition voltage, each ignition coil having a cable-free detachable electrical connection with adjacent electrical components in the high tension block, the high tension block also comprising a number of contact means, one in each connection casing, which contact means establish a resilient cable-free detachable connection between one ignition coil and one spark plug, for transmission of high tension current from the ignition coil to the spark plug, and a plurality of sealing elements, one for each connection casing, each sealingly surrounding a spark plug when the cartridge unit is connected to the spark plug.