Equations and Methods for Testing Hydrogen Fuel Consumption using Exhaust Emissions

Although hydrogen ICE engines have existed in one sort or another for many years, the testing of fuel consumption by way of exhaust emissions is not yet a proven method. The current consumption method for gasoline- and diesel-fueled vehicles is called the Carbon-Balance method, and it works by testing the vehicle exhaust for all carbon-containing components. Through conservation of mass, the carbon that comes out as exhaust must have gone in as fuel. Just like the Carbon-Balance method for gas and diesel engines, the new Hydrogen-Balance equation works on the principle that what goes into the engine must come out as exhaust components. This allows for fuel consumption measurements without direct contact with the fuel. This means increased accuracy and simplicity. This new method requires some modifications to the testing procedures and CVS (Constant Volume Sampling) system.

This paper will explain the principles behind the new testing methods as well as the equipment required to accurately test hydrogen-fueled vehicle fuel consumption. The techniques have been optimized for the roller chassis dynamometers, and the current BMW configuration is given as an example. Since Hydrogen-Balance works for fuel cells as well as ICE (Internal Combustion Engines), the industry wide implications are large. Substantial time and effort can be saved by simply modifying existing testing systems instead of installing completely new hydrogen supply and measuring devices.