Ammonia as a Spark Ignition Engine Fuel: Theory and Application

Anhydrous ammonia has been demonstrated to operate successfully as a fuel for spark ignition engines. Principal requirements are that it be introduced in the vapor phase and partly decomposed to hydrogen and nitrogen.

Spark timing for maximum performance must be advanced slightly for ammonia but sensitivity to spark timing is little greater than with hydrocarbons. Increasing the cylinder wall temperature aids in effecting successful and reliable operation.

The maximum theoretically possible indicated output using ammonia vapor is about 77% of that with hydrocarbon. Specific fuel consumption increase twofold at maximum power and 2-1/2 fold at maximum economy when using ammonia as a replacement for hydrocarbon.