Hydrogen as engine fuelChange what we burnThameem Abbas I1Hydrogen Atomic Number 1Mass Number 1,2,3Color - ColorlessGeneral Phase GasMelting Point 13.99 KBoiling Point 20.271 KDensity (STP)-.08988 gL-1 Density (l) -.07099 g/cm3 Calorific Value 593,661 Kcal/Kg2Why Hydrogen ?Hydrogen is light (very light) Has a very high calorific value (an order of magnitude higher than petrol)Produces Water (Steam)Requires non usage of platinum spark plugsCalorific Values of Various FuelsKJ/KgWays to use HydrogenHydrogen can be used in either of the ways:Directly burn H2 in the engine in place of gasolineIn the form of electricity from a hydrogen fuel cell

The latter is more commonly used due to its convenience

But the former can provide much better results if the required modifications are made to the engine design 5Fuel CellFuel cells are a safe and more practical way to use hydrogen as fuelBut they are not as powerful as IC engine powered vehicles

AdvantagesHigh safety Zero harmful emissionsCan achieve very high efficiency

DisadvantagesHydrogen fuel cells are highly expensive due to construction materialsRequire high purity of fuel and oxygenReplacement costs can be very highHas not penetrated growing markets yetHydrogen IC EnginesAs weird as it sounds, hydrogen based IC engines do existThey have existed since 1806It was the De Rivaz engine

De Rivaz EngineThe De Rivaz engine was very primitive.It had no timing mechanism but relied on manual operationHydrogen was stored in a balloon connected by a pieOxygen was supplied to the air inletA Volta cell was used for ignitionDe Rivaz Engine SchematicA = CylinderB = Spark IgnitionC = PistonD = Hydrogen BalloonE = RatchetF = Inlet and exhaust pistonG = Handle for second piston

Hydrogen IC EnginesHydrogen IC engines merely replace gasoline with HydrogenThis requires a number of modifications to be made to the engine

ModificationsHardened Valves and Valve seatsStronger connecting rodsNon platinum tipped spark plugsHigher Voltage ignition coilFuel injectors designed for gasLarger crankshaft dampenerStronger head gasket materialModified intake manifoldPositive pressure superchargerHigh temperature OilModificationsThe cause for the requirement of all these modifications is:Very high calorific value of hydrogen High efficiency burning of hydrogenGaseous phase of HydrogenChemistryThe chemistry of the hydrogen engine is fairly simple:

But at high temperatures, they do produce a small amount of Nox due to oxidation of nitrogen in the air(applies only for air breathing engines).

Power OutputThe power output of the modern hydrogen internal combustion engine vehicle is 20 % of a direct injection gasoline engineIn hydrogen IC engines , themselves , a direct injection engine is 42% more powerful than a carburetor fitted engine. This is due to higher efficiency of combustion.DisadvantagesHydrogen cannot be stored as a gas and thus a liquid

Liquid Hydrogen is not feasible at room temperatures.

Thus it can merely be stored at high pressureThis also requires the use of stronger fuel tanksHydrogen is also explosive Platinum should be avoided near Hydrogen

Hydrogen TankHydrogen tank by a German manufacturer