The test of the hydrogen generator on the internal combustion engine of the car is considered in the work. In the machine, HHO and fuel are jointly burned to reduce fuel consumption and exhaust emissions. Numerous studies prove the undeniable advantage of using a car using a hydrogen generator compared to traditional fuels. The use of a lean combustible mixture in internal combustion engines reduces the volume of exhaust gases and increases thermal efficiency. Experimental results show that by adding KOH with a concentration of (35-50 g/l) to the cell, fuel consumption can be reduced (8.4-43.6%), and exhaust pollutant emissions are reduced. Thus, adding hydrogen to an internal combustion engine can reduce fuel consumption and vehicle exhaust emissions.