- #1
Steve Aplin
- 4
- 1
I figure my 2.4 liter Volvo will burn about a liter of gasoline over an hour of idling (source: Natural Resources Canada). Since a liter of gasoline contains roughly 33.8 million joules (~9.4 kilowatt-hours) of energy, I figure that that means my car idles at a power output of around 9.4 kilowatts.
The tachometer indicates rpm of ~700 while idling.
Can I infer from that that when I'm climbing a steep hill at 100 kilometers per hour and the tach is showing rpm of around 3,500 that the engine at that moment is outputting around 47 kilowatts?
It seems logical to me to assume that if the engine speed is 5x on the hill climb then its fuel consumption is 5x that of idling, and that fuel consumption = power output.
Is this a reasonable assumption?
(I know my gasoline engine is at most 20 efficient, and I am not trying to say that moving a 3-ton vehicle at 100 kph up a steep hill requires 47 kW. I am talking only about the gross power output of the fuel.)
The tachometer indicates rpm of ~700 while idling.
Can I infer from that that when I'm climbing a steep hill at 100 kilometers per hour and the tach is showing rpm of around 3,500 that the engine at that moment is outputting around 47 kilowatts?
It seems logical to me to assume that if the engine speed is 5x on the hill climb then its fuel consumption is 5x that of idling, and that fuel consumption = power output.
Is this a reasonable assumption?
(I know my gasoline engine is at most 20 efficient, and I am not trying to say that moving a 3-ton vehicle at 100 kph up a steep hill requires 47 kW. I am talking only about the gross power output of the fuel.)