Angsistema ng pag-aapoyay isang mahalagang bahagi ng engine ng gasolina. Ang pagganap ngsistema ng pag-aapoy has a great impact on the engine's power, fuel consumption and exhaust pollution. All the equipment that can generate electric spark between the two electrodes of the spark plug is called the engine "sistema ng pag-aapoy". It is usually composed of batteries, generators, distributors, ignition coils and spark plugs.