Abstract: An air intake apparatus for supplying air to an internal combustion engine (1), comprises a unitary hollow enclosure (50), housing a motor vehicle battery (16), an air filter (9) and an air compressor (10) which when activated compresses air supplied to the engine (1). An engine air supply path through the enclosure (50) passes from an air inlet (52) to the enclosure to an air outlet (54) from the enclosure via the air filter (9). The apparatus includes an automatic air bypass (13, 74, 84) within the enclosure (50) that directs air in the air supply path to the air compressor (10) when this is activated, and which allows air to in the air supply path to bypass the air compressor (10) when this is not activated.