nurey:
This your story is better than a lullaby

Give me an AUDI Q7 6.0L V12 QUATTRO TDI any day and I will make any turbo charged petrol engine look extremely stupid

nurey:
This your story is better than a lullaby

Give me an AUDI Q7 6.0L V12 QUATTRO TDI any day and I will make any turbo charged petrol engine look extremely stupid

9icetoo:

tell them nuery. just remembered one of siennas story where a diesel burning BMW the size of a garden shed ripped his car.
once saw a diesel driven v6 Passat TDI on the highway, driven by a woman. it the red I by the way. nodded my head in approval.

nurey:
This your story is better than a lullaby

Give me an AUDI Q7 6.0L V12 QUATTRO TDI any day and I will make any turbo charged petrol engine look extremely stupid

policy12:

Go for solar car....

lonelydora:


Passat V6 TDI overtook me on the highway while I was on 140km/hr. The more i stressed to catch up with him, the more it looked like I was crawling. O'boy, that was the day I stopped believing diesel cars are slower.

Correspondence:

Speed kills. Beware!

lonelydora:


Not for a long ranger like me. Imagine doing 90/100km/hr from PH to Kaduna/Abuja. No nah.


Safety is of the Lord's

nurey:
This your story is better than a lullaby

Give me an AUDI Q7 6.0L V12 QUATTRO TDI any day and I will make any turbo charged petrol engine look extremely stupid

lonelydora:


Passat V6 TDI overtook me on the highway while I was on 140km/hr, almost floored to 165/170km/hr, but the more i stressed to catch up with him, the more it looked like I was crawling. O'boy, that was the day I stopped believing diesel cars are slower.

nurey:
This your story is better than a lullaby

Give me an AUDI Q7 6.0L V12 QUATTRO TDI any day and I will make any turbo charged petrol engine look extremely stupid

Emycord:
Simplify it like this pdp vs apc, buhari vs goodluck thats the only way they can get ur as for we biafrans its a referendum

tolexy05:
Abeg sumariz dis jare...... Make I read son comment first

Psychodavidovic:
I am not understanding.

Autofreeman:
A story on the Internet goes on about how a man had to spend 14,000 USD fixing his Porsche Cayenne after his wife accidentally filled it up with diesel at the fuel dispenser instead of petrol. He thought bleeding the tank, pump and fuel lines and replacing the plugs would solve his problem, but no, apparently Porsche AG do not like their stuff being repaired like that; he had to give the car back to them for repairs and then…well, he also had to part with slightly more than $10,000. Apparently Porsche warranties do not cover stupidity. This got me thinking: what is the big deal about whether a car runs on petrol or diesel? Does the car still not require periodic filling up? Aren’t they all started with a key (at least for motor vehicles)? Don’t the controls work the same for both types of cars? What is the difference anyway?

autofreeman.com.ng

These are the differences:

Injection:

In the days of old, petrol was mixed with air, roughly in the ratio 1:15 respectively, by a device called a carburetor. Subsequent technology introduced fuel injection, but the main basis of fuel delivery for a petrol engine was that it was mixed with air outside the cylinders before the mixture was set on fire within the cylinder by means of a spark plug. Diesel engines had the fuel injected into a mass of hot compressed air for them to run efficiently, and this difference brings us to the next difference, ignition.



Ignition:

The physical qualities of petrol and diesel are vastly different. Petrol is a lighter, more volatile liquid (and thus more flammable) than diesel, which is heavier, oily and stinks to high heaven. As such, their combustion properties are different. Petrol requires a naked flame, and not necessarily a very hot one, before going boom. But liquid petrol does not burn. Yes you read correctly, liquid petrol does not burn; petrol vapor does. The volatility of petrol means it is very easily vaporized, which explains how early examples of petrol engine used simple carburetors. Later (fuel-injected) models use low pressure injectors to vaporize the fuel before it is burnt in the engine.

Diesel, being heavier and more viscous, is even more reluctant to combust in liquid form. To compound matters, it does not vaporize easily, nor will it catch fire no matter how naked the flame introduced is. When injected into the engine, it has to go through extremely high pressure injectors which then feed a very tiny nozzle to completely atomize the diesel oil. If it won’t burn when in liquid form, and it won’t catch fire when sprayed out of a nozzle, how then does it work? Pure air is sucked into the diesel engine, which air is then compressed to a very small volume. Remember Charles and Boyle from First Form Chemistry? The compressed air, now at high pressure, becomes extremely hot (roughly 550° C), and it is to this hot, squashed gas that the diesel oil is injected. It then has little choice but to burn, releasing large amounts of energy in the process.

Just to add a point on injection: engineers of petrol engines have tried diesel-like direct injection of petrol instead of the typical external mixing of air and fuel. Petrol’s physical characteristics make introduction of fuel after the induction valves have closed a tricky affair, and different manufacturers have achieved this with varying levels of success. Mitsubishi call their work GDI (Gasoline Direct Injection), and it almost works. Toyota calls theirs D4 (Direct injection, 4-stroke cycle), and it almost doesn’t work. Diesel engineers, on the other hand, have only had to choose between direct injection, where the injectors feed the cylinders directly from the pump, or common-rail, a fuel delivery system that works in a manner suspiciously similar to that of an irrigation scheme.



Compression Ratio:

Sounds fancy and complicated, but compression ratio is the relationship between the air coming into the engine before it is compressed and after it is compressed. A higher compression ratio means a higher degree of squeezing; therefore a low compression ratio means little squeezing. Diesel engines typically have higher compression ratios than petrol engines so that the compressed air can reach a temperature high enough to ignite the diesel: remember Charles and Boyle? Petrol engines have lower compression ratios to prevent pre-ignition, a case where the air-fuel mixture catches fire in the cylinder before it is supposed to. The difference in compression ratios also explains why drivers talk of “heavy” gears in a diesel: it is difficult to get a smooth downshift in a diesel without double declutching or waiting for the engine revs to decay completely before shifting because of the closed-throttle compression resistance offered by the engine.



Power and Torque:

It is difficult to explain the difference between power and torque without revisiting high school physics, but it can be put down to this: torque is the amount of “twist” in the driveshaft provided by the engine, while power is the rate of that twist. Does that make sense? Another way of looking at it is this way: torque is what gets you going, while power is what keeps you going. Torque determines acceleration or load-pulling ability (depending on the gearbox), while power determines absolute speed. Better now?

Petrol engines tend to have a lot of power, but little torque, mostly depending on engine capacity and design. That explains why smaller versatile vehicles tend towards petrol power. Diesels have it the other way round: they usually have excellent torque characteristics, but low power, especially in the upper reaches of the rev range where maximum power is reached. This is why heavy commercial vehicles and tractors come fitted with oil-burning mills.

So, if you want to set a land speed record, concentrate your efforts around a petrol engine; if you want to move a chunk of that land, slowly, think diesel.



NVH (Noise, Vibration and Harshness)

Show me a man who has driven a (production) diesel powered Rolls-Royce/Bentley limousine, and I will show you a liar. The smoothest internal combustion engines are almost always petrol powered. Old car magazines that I go through describe diesel engine smoothness (or lack thereof) in amusing ways, using analogies like “…kicking a rusty can down a cobbled street”, “…an old oil drum rolling down the face of a quarry” and “…loose gravel inside a food blender”. All these describe the aural signatures from diesel engines of eras past, though advancement in noise suppression has made life bearable for owners of newer diesel engines.

The ruggedness of these diesel engines comes from the fact that they operate at much lower engine rpm (making frequency lower and harder to damp or “rectify”, to use an electrical term), and that they are made from much heavier components than their petrol counterparts, giving them high moments of inertia. On a bad day, the simple idling from a diesel engine is enough to shake and rattle an entire vehicle. The low idling speed of the engine also give the engine a characteristic “knock”, not the mechanical defect, but the noise, unlike the smooth thrum of a high-speed-idle petrol.

Day to Day Commute

From the above chatter, it might seem that a diesel engine might not be appropriate for most drivers, and typically it shouldn’t. It is rattly, sluggish, and heavy and spews an embarrassingly dark fog from the tail pipe if not well maintained. Never mind the inherent reluctance of the driver of a small car to be seen filling up at the black pump, not so much locally but in Europe and the States.

But despites the cons, there are a few pros to support driving a diesel powered vehicle. They use a lot less fuel, giving almost twice the fuel economy of equivalent petrol engines; and diesel is dirt cheap, simply because diesel is material as close to dirt as you will ever feed your car. The torque characteristics also mean there will be less shifting, making them a bit more relaxing to drive, since the engine is able to pull higher gears at lower speeds compared to petrol units. The massive torque also enables one to lug heavier loads without straining the engine and drive-train excessively.

There is also a lack of high-tension electrical systems to attend to (coils and spark plugs), making them more reliable. The heavier parts also make them last longer. These heavier parts also absorb a lot of heat, so in cold weather, there is need for a glowplug, a small electric heater in the cylinder’s pre-chamber to warm the engine for a proper start. The warming act is sometimes referred to as kuchoma (Swahili for “burning”) by many drivers.

Think of this: the gun has been called The Great Equalizer. A thin child could face a full-scale Sumo wrestler with less knocking of the knees if he had a rifle, or at least a pistol, in his hands. In the same vein, a diesel engine could face off a petrol engine with less red-faced bashfulness if equipped with the automotive equivalent of the Great Equalizer: a turbocharger.


Turbocharger Technology

Boost technology (turbocharging and supercharging) will be explained elsewhere in detail, but here I want to talk about its effect on a diesel engine.

As with any other engine, a turbocharger fitted to a diesel powerplant raises the specific power output (horsepower rating), lowers emissions, improves efficiency and offers higher levels of refinement, the exact same weaknesses of a diesel as highlighted in a comparison against a petrol engine. These improvements have so popularized turbocharged diesel power that it is the norm nowadays rather than the exception. Just how popular are these turbodiesels? As of 2006, 50% of new vehicle registrations in Europe were turbocharged diesel models.

When turbocharged, diesel engines do not need adjustment of their compression ratios, since there is no risk of pre-ignition (fuel is injected at the point of ignition), making them ideal candidates for this technology. Since the turbocharger boosts power output, a turbodiesel now has the triple benefit of having the massive torque of a typical diesel and top end power of a petrol engine, while still offering outstanding fuel economy.

To add a little perspective to this whole equalizer business, chew on this: A Skoda Octavia diesel sedan (powered by Volkswagen and turbocharged), is faster over the quarter mile than a Mark IV Volkswagen Golf GTI (petrol power, manual gearbox) and a Rover 200 (another petrol powered hatchback, automatic gearbox), though this test was done mainly to demonstrate how low the VW GTI had sunk rather than to highlight the prowess of the Skoda. But the result still applies.


Summary up: petrol is what to go for if you are in a real hurry and you want smoothness to supplement your haste, while diesel is the choice for penny-pinching, load-lugging environmentalists with nothing urgent on their schedules. Turbodiesels offer a compromise between the two, while turbocharged petrol cars are another league up. Just remember, whatever you choose, try not to end up spending 14,000 dollars fixing the miscalculations of an absent-minded spouse like our friend on the web did.

Source:autobazarr.co.uk

nurey:
This your story is better than a lullaby

Give me an AUDI Q7 6.0L V12 QUATTRO TDI any day and I will make any turbo charged petrol engine look extremely stupid

metallisc:



i am supposing that you have a national budget for fuelling the v12 6.0 in this economy!?