Burning fuel and a motor's efficiency

[Karol]

Homework Statement

A motor burns 20 liter per hour. the fuel's combustion heat is 6.6E6[cal/liter] (i don't know if it's kcal or cal, but i assume it's cal). the motor produces 40 [Hp], what's the efficiency.

Homework Equations

1[Hp]=746[W]. 1[W]=[Joule/sec]
1[cal]=4.186[Joule]

The Attempt at a Solution

40[Hp]x746x3600=107,424,000[Joule/hour]
20[liter]x6.6E6[cal/liter]=13.2E7[cal/hour]
13.2E7[cal/hour]/4.186=31,533,684[Joule/hour]
The fuel supplies less power the the motor's output. not true

 

[CWatters]

1[cal]=4.186[Joule]

13.2E7[cal/hour]/4.186...

 

[Karol]

Thanks