Why are diesel engines limited to such low revs?
Every diesel I’ve driven has a red line and limiter at between 4,500 and 5,000 RPM instead of the 6,000-7,000 of a typical petrol engine of equivalent bore/stroke. Many modern turbodiesels are still pulling hard when the limiter calls an end to the fun, so does anyone have any idea why these engines are limited to such low revs?
What’s the best rev range for a petrol car?
Many small-ish petrols develop maximum torque at 4000-4600 rpm and are geared 20-21 mph/1000 in fifth . Running most of the time at these revs would mean exceeding NSL or being in third or fourth gear, which doesn’t sound either relaxing or economical.
Why do engines use more fuel at high revs?
The more you press the accelerator, the more fuel you are letting in regardless of the RPM or speed. This is because accelerator pedal is connected to the valves that are connected to fuel injectors and control the fuel inflow to the combustion chamber just like you control water inflow from the water taps through the knobs on top.
Why are petrol engines cannot run at high compresion ratios?
Petrol engines cannot run at very high compresion ratios because the burning of the fuel cannot be controlled without retarding the ignition (spark) which defeats the object.
When do engines consume more fuel, at low revs or high?
Now in most of the cases, when you drive at low rev (at a higher gear with low speed), most of the fuel is consumed there. If you’re at a low gear and at a higher speed, that contributes in more fuel consumption as well since you’re on a lower gear and the engine is running at a higher speed. So its crucial to property vary the speed. Drive safe!
What does it mean when your engine revs up?
If your engine revs up as you press down on the accelerator but your vehicle doesn’t accelerate as per usual or as you would expect, it’s a troublesome sign that can lead to a full-blown transmission failure. Transmission slipping, or gears slipping, is one of the most common transmission problems on both manual and automatic transmissions.
Petrol engines cannot run at very high compresion ratios because the burning of the fuel cannot be controlled without retarding the ignition (spark) which defeats the object.