Originally posted by bjork:
Hmm.. i always wonder why cars tt run on diesels tend to have faster pick up speed then cars tt run on petrol..
Like Taxis & Cabby..
Before i know they zoom off once the traffic turn green...
Why huh?
Here are some facts with regards to ur question, hope it may help you.
One big difference between a diesel engine and a petrol engine is in the injection process. Most car engines use port injection or a carburetor rather than direct injection. In a car engine, therefore, all of the fuel is loaded into the cylinder during the intake stroke and then compressed. The compression of the fuel/air mixture limits the compression ratio of the engine. A diesel compresses only air, so the compression ratio can be much higher. The higher the compression ratio, the more power is generated.
Diesel fuel has a higher energy density than petroluem. On average, 1 gallon (3.8 L) of diesel fuel contains approximately 155x106 joules (147,000 BTU), while 1 gallon of petroleum contains 132x106 joules (125,000 BTU). This, combined with the improved efficiency of diesel engines, explains why diesel engines get better mileage than equivalent gasoline engines.
Got it from my studies in mech engg.