Specific Fuel Use

Basics

• Fuel used per second
• Fuel used per meter/second
• Also need to see if RPM = Fuel Use, or if more/less fuel can be "dosed"; if so by how much does it vary etc
• Thinking of using this moreso for a vehicle as a whole, not just an engine on a Dynamometer
  • So taking into account Vehicle Mass , Vehicle Aerodynamics , Transmission etc
• Also how/where would someone measure fuel flow and is this not going to match up 100% with the "true fuel flow / use" if so by how much

Case Study

User: Eric

• I think my car is most efficient (in a fuel used per seccond, per common meters moved, but at varying top constant speeds (~40-65 mph?)( Highway Style Driving Fuel Use ) at ~50-55mph?
• This is just looking at RPM
• Can grab hard numbers later + convert to metric
• Also try and find out the answers to the questions under basic

Somewhat related, but off topic car ramblings to clear up later

• This also ties into ECU / Engine Tuning + adding custom sensors / gauges / an Open Source Vehicle HUD stuff, which could be neat, especially if i could improve efficiency and/or the effectiveness of the Catalytic Converter (some sort of weak "exhaust smell" even noticeable from outside of the door when it runs (know from scraping morning dew/ice off with defrost on), assuming unburnt hydrocarbons, (can NOx be smelled?) via better "swing" from lean to rich / making sure that is accurate
  • Also look into if catalysts degrade/are degraded and/or if there is Catalyst Poisoning / Particulate Filters that a simple cleaning could fix
• Granted also return on investment on that hardware side would probably be quite low!
• Was wondering about Hub Motor (potentially one for each wheel!) + Free Piston Linear Generator based Range Extender / Plug-In Hybrid battery...
• Granted in terms of making a Street Legal Non-OTS Vehicle i don't know if using an existing frame (ie gut an older, but reliable car (potentially with cheap transmission/general parts) such as the honda accord i have), and make some frankensteinian abomination with is is better than making a Custom Frame.
  • And in theory, a Direct Drive Hub Motor would just need a Suspension and (albeit way over my head high voltage, correct?) wiring, not a mechanical transmission, right?
  • Also how one does airbags / certifies a custom car, NOT a "Dune Buggy" / Track Car too, something that could be a "Daily Driver", just Makerspace level, not mass produced and with way more unconventional features that would be too risky for many companies to take so are 10 years off from mainstream OTS cars/vans etc (and even then they are getting more and more anti-R2R friendly as well)
• This is all way over my level as of now, but in the spirit of Document Everything (in case any of you could benefit from this information/realize it before i am capable), as well as just documenting this before i forget it i thought i'd write it on-wiki

Internal Links

• Engine Efficiency

External Links

• The Wikipedia Page on (Fuel) Consumption Maps
• The Wikipedia Page on Brake-Specific Fuel Consumption
• The Wikipedia Page on Specific Impulse (GRANTED this is in space applications, so you can quite literally get to Spherical Cows in a Vacuum level of simplicity, and it is just the engine. Also short of monopropellant thrusters / ion thrusters / arcjets etc you are needing an oxidizer as well unlike vehicles in earth's atmosphere...unless you are Skylon (for some parts of it's flight path)!