What determines fuel efficiency? Why some fuels are more fuel efficient than other fuels

[nec209]

From what I understand fuel efficiency is define by two variables.

1 Type of fuel being used.
2 The type of engine.


Where engineers make the engine more fuel efficient.

The type of fuel being used.

A fuel that is more densely packed molecules is more fuel efficient than a fuel that is less densely packed molecules. A fuel that is less densely packed molecules is less fuel efficient.

We use fossil fuels because it is cheapest out there and the most fuel efficient thus densely packed molecules.

 

[swansont]

You also have to have energy liberated under combustion. Water is more dense than gasoline but it's a lousy fuel. But hydrocarbons have lots of potential bonds to make with oxygen.

[CasualKilla]

With combustion fuels, the efficiency is normally driven by temperature difference between the inside and outside of the engine. Cars in northern canada are much more efficient than cars in Equitorial New-Ginea for example.

[swansont]

With combustion fuels, the efficiency is normally driven by temperature difference between the inside and outside of the engine. Cars in northern canada are much more efficient than cars in Equitorial New-Ginea for example.

 

I get better gas mileage commuting in 20ºC weather than in 0ºC weather (this morning I got 35mpg, while 25-28 mpg was the norm when the temperatures were colder). The issue is more than a simple application of thermodynamics

[nec209]

You also have to have energy liberated under combustion. Water is more dense than gasoline but it's a lousy fuel. But hydrocarbons have lots of potential bonds to make with oxygen.

 

The more bonds the more fuel efficient like hydrogen the space shuttle uses. .

 

We use fossil fuels because it is cheapest out there and the most fuel efficient thus it also has the most bonds.

 

Like hydrogen fuel that rockets use is the most dense fuel.

With combustion fuels, the efficiency is normally driven by temperature difference between the inside and outside of the engine. Cars in northern canada are much more efficient than cars in Equitorial New-Ginea for example.

 

 

I don't know why they don't discovere or made in lab a super fuel.

 

Just think of car going to gas pumps only two times in month? Or the Concorde a supersonic plane going from New York to LA non stop or from New York to LA and back to New York!!

 

They spend billions on wars but do not spend money to discovere or made in lab a super fuel.

[swansont]

 

The more bonds the more fuel efficient like hydrogen the space shuttle uses. .

 

We use fossil fuels because it is cheapest out there and the most fuel efficient thus it also has the most bonds.

 

Like hydrogen fuel that rockets use is the most dense fuel.

 

Liquid hydrogen has a density of 71 g/L. The density has nothing to do with the efficiency. You were on the right track before, saying it's the density of the number of bonds you can remake.