Valve controlled combustion system

An internal combustion engine combustion system, comprising:

• an ignition element configured to ignite an air-fuel mixture compressed within a combustion chamber of an internal combustion engine;
• an ignition actuation member movable relative to the ignition element between a first position in which the ignition actuation member prevents contact of the air-fuel mixture with the ignition element to prevent ignition of the air-fuel mixture when present in the combustion chamber, and a second position in which the ignition actuation member permits ignition of the air-fuel mixture by exposing the ignition element to the air-fuel mixture when the air-fuel mixture is present in the combustion chamber;
• and
• an isolation cavity, an isolation member, and a radiation source, the isolation member seals the radiation source within the isolation cavity when the actuation member is in the first and second positions, the radiation source is configured to produce radiation and is coupled to the actuation member to move with the actuation member between the first and second positions, the isolation member is configured to allow the radiation to pass through the isolation member to form the ignition element and ignite the air-fuel mixture when the actuation member is in the second position.