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User:calum User:amx109 User:samthetechie User:russ


We achieved engine firing with a 150 cc, two valve engine (the SV150 by Mountfield) fuelled by running on hydrogen gas and air mixture.

  • Capacity 148cc
  • Net Power Output 3.5 horsepower i.e. 2.6 kilowatts @ ~3600rpm


Further Research

Hydrogen use in a Combustion Engine

NOx Emissions

The amount of NOx formed depends on: • the air/fuel ratio • the engine compression ratio • the engine speed • the ignition timing • whether thermal dilution is utilized

Air/Fuel Ratios

Because of hydrogen’s wide range of flammability, hydrogen engines can run on A/F ratios of anywhere from 34:1 (stoichiometric) to 180:1. The A/F ratio can also be ex-pressed in terms of equivalence ratio, denoted by phi (Φ). Phi is equal to the stoichiometric A/F ratio divided by the actual A/F ratio. For a stoichiometric mixture, the actual A/F ratio is equal to the stoichiometric A/F ratio and thus the phi equals unity (one). For lean A/F ratios, phi will be a value less than one. For example, a phi of 0.5 means that there is only enough fuel available in the mixture to oxidize with half of the air available. Another way of saying this is that there is twice as much air available for combustion than is theo-retically required. Hydrogen

Other Homebrew Hydrogen Fuelled Engine Experiments

Lawnmower engine running from a balloon of hydrogen


  • Phi is the 'equivalence ratio' which is the actual air/fuel ratio divided by the stoichiometric air/fuel ratio. If the value for phi is less than one, the mixture has excess air and therefore is lean. If the value for phi is greater than one, the mixture has excess fuel and therefore rich.


Lab 23


29/6/11 at 2am...


  • For the Lulz
  • In the name of Science and Humanity