Abstract: Internal combustion engines operate by igniting a mixture of liquid fuel and air inside its combustion chamber. The energy from the ignition is converted to mechanical energy that is used to power a vehicle. Research indicates that adding hydrogen gas into the combustion chamber improves the efficiency of the engine. The present invention is an electrolysis system that produces hydrogen and oxygen gases and injects them into the fuel line of the engine to create a mixture of the gases and the liquid fuel that is subsequently introduced into the combustion chamber for ignition. The operating temperature of the engine is lower if the gases are injected into the fuel line rather than directly into the combustion chamber.