rambler said:
The diesel will have more torq, which is hard to explain but it will get through tough spots better, even tho it does not have more actual power.
--->Paul
Why hard to explain more power from the diesel? Simple answer: Compressibility ratio in diesels (14:1 to 25:1) is higher than that (8:1 to 12:1) of gasoline and higher energy capacity in diesel fuel than gasoline.
To understand the differences between the diesel and the gasoline, we need to know the differences between the fuels and the design of engines:
Here are main differences:
FUEL
Diesel (in chemical form of C14H30) has longer carbon form than Gasoline (in chemical form of C9H20.) This means diesel can be refined easily, in less number of stages than gasoline which much be refined more. This is why gasoline price is higher. But, diesel (more carbon elements) has more energy capacity, meaning that 1 liter of diesel will give more energy than 1 liter of gasoline. 1 lt of diesel has a capacity of about 40,000 kjoules while 1 lt of gasoline has about 35,000 kjoules. So, diesel has about 15% higher energy capacity than gasoline. Long carbon form (diesel) also means less volatility, higher boiling point (even higher than water) which is also an advantage.
Disadvantage of more carbon is more unburned carbons (causing CO gas) which is not good for environment.
ENGINE
Diesel engines are designed to give higher compression ration (around 20:1) while in gasoline, it is around 10:1. If we use same amount of fuels, then, this means diesel will release much higher energy, or, power. Here, we need to look at the efficiency (chemical combustion efficiency, and overall efficiency.) Diesel engines have higher efficiency than gasoline engines which will be effected by how well air-fuel are mixed, how well mixture is evaporated, etc etc.
So, if you need higher power, use higher energy capacity fuel and higher compression ration. These mean the diesel. Total power that will drive a car of 1 ton with a speed of 50 m/h is much less than total power that will drive a tractor with a plough behind with a speed of 10 m/h. So, even LPG (butane/propane) gas with a much lower energy capacity can be used at a car from which we need speed only.