56
votes
Accepted
Why do heavy vehicles almost always use diesel engines?
Torque is the name of the game. High torque is needed to move heavy loads. If comparing a gasoline engine to a comparable diesel engine the diesel will always have higher torque. The higher torque ...
- 16k
29
votes
Small amount of wrong fuel type put in the tank
The main concern with using petrol in diesel systems is that diesel is used to lubricate the fuel pump, which petrol cannot perform adequately, which will shorten the useful life of the fuel system.
...
- 39.1k
29
votes
What happened to my car?
Being a diesel and that the engine ran for a minute with the ignition turned off, makes it highly likely that you experienced diesel runaway.
During normal operation, diesel is used as fuel for the ...
- 24.9k
28
votes
Why do heavy vehicles almost always use diesel engines?
A major, but often overlooked, reason for the dominance of gasoline engines in passenger vehicles is the need for diesel engines in heavy vehicles. A given quantity of crude oil, depending on its ...
- 1,723
22
votes
Why do heavy vehicles almost always use diesel engines?
To OP’s main question: “Why do heavy vehicles almost always use diesel engines?”
Answer: Cost and dependability. Diesel engines are significantly more expensive, but have lifetimes many times greater ...
- 221
16
votes
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Diesel Engine Runaway - What is it?
Since the diesel has no physical throttle, power is controlled by limiting fuel. Air is always available so any unintended, un-metered fuel will cause the engine to increase rpm and power output. The ...
- 11.6k
16
votes
Accepted
Small amount of wrong fuel type put in the tank
The main problems from misfueling a diesel car with petrol stem from the fact that (as Zaid points out) petrol doesn't provide the lubrication effect of diesel fuel and as a solvent it can actually ...
- 9,989
13
votes
Accepted
Why are VW recalling their cars to remove a defeat device?
The recall is not to remove the cheating logic; it is to actually make the engines meet emissions requirements so they do not violate the law any more. From Autoblog's initial article on the scandal:
...
- 39.1k
13
votes
Accepted
Two-Stroke Diesel Engine - Do they use forced induction on them?
The only two stroke diesel i'm aware of is the Detroit diesel. The Detroit diesel does use forced induction but not in the way that you think. From your description it sounds like your describing a ...
- 16k
13
votes
Accepted
Is it possible for a diesel engine computer to detect (and prevent) a runaway condition?
The common way that effective overspeed protection is provided on diesels in the oil and gas industry is way more simple than using electronics to effect a shut down.
The only effective and reliable ...
- 605
12
votes
What's the cause of Diesels' typical clatter noise?
Two types of sounds
There are two sound types that emerge from a diesel engine.
Combustion Noise
Mechanical Noise
Combustion noise is created by the compression ignition process which compresses ...
- 33k
12
votes
Accepted
How did they start diesel engines before the glow plug was invented?
Glow plug is merely an aid for starting the engine. There are many designs still produced today without any glow plugs (eg military diesels run without any electricity), and even many modern diesel ...
- 805
12
votes
ATF in engine oops
I would run the engine again for a few minutes and then drain that engine oil as it will have any ATF that was still in the galleries.
Then fit a new filter and refill with fresh oil.
After that you ...
- 34.6k
12
votes
Accepted
Scraping sound in new small engine
I actually decided to go ahead and just tear into it no matter the answer and can make the following statements:
Bore and piston rings were absolutely immaculate and there was no scraping whatsoever
...
- 621
11
votes
Why do heavy vehicles almost always use diesel engines?
Given two engines of similar weight, both operated at their respective optimum efficiency (i.e. maximum mechanical work done per unit of chemical enthalpy in the burnt fuel), you will end up with ...
- 111
11
votes
Accepted
How are diesel engines better for the environment than gasoline?
They aren't better for the environment
But efficiency is often confused with emissions. The average person would think that because diesel engines are more efficient and burn less fuel, they must be ...
- 39.1k
11
votes
Small amount of wrong fuel type put in the tank
This will not be a problem - in fact, some of the older truckers used to add 2% of petrol to the diesel to help in winter conditions to help reduce waxing of the diesel fuel.
- 34.6k
11
votes
VW Polo Engine Oil Light Blinking on hill
I have a VW TDI diesel, but an earlier model.
Your oil light comes on when there is a gradient but not because of a gradient. A mechanic who blames the tilt of the ground for the light on the dash ...
- 5,510
10
votes
Why does a petrol engine need to maintain an air-fuel ratio, while a diesel engine doesn't?
It sounds like you already know why a gasoline engine keeps the fuel/air ratio as close to the stoichiometric ratio as possible, but just for the sake of information for anyone else:
The ...
- 2,055
10
votes
Accepted
Why don't all diesel engines have throttle plates?
tl dr: By adding a throttle plate, it creates the vacuum needed to draw in gasses from an EGR valve.
Since diesel engines are designed to run lean, they don't need throttle plates to run. They ...
- 153k
10
votes
Accepted
What would cause a short to ground while driving - how to locate the problem?
The most likely cause is that the cable that runs down to the starter motor has been rubbing against the body or the engine and has worn through the insulation.
- 24.9k
9
votes
Accepted
What's the cause of Diesels' typical clatter noise?
The engine operates on high compression to ignite the fuel at very low RPMs which gives it it's distinctive sound. The lower RPM makes the ignition of each cylinder easier to hear and the compression ...
- 256
9
votes
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Diesel engine timing?
Diesel engine timing is accomplished through the fuel injectors (they inject fuel at the proper times). Proper timing prevents pre-ignition because there's no fuel in the cylinder yet to ignite. Glow ...
- 4,900
9
votes
9
votes
Accepted
Why does "i" stand for petrol?
The i is a leftover from the 1970s, when a few companies (BMW and Mercedes, notably) started replacing the carburetor on their petrol engines with fuel injection. The marketing department saw an ...
- 4,422
8
votes
Accepted
Would a non-turbo diesel perform better in high altitudes than a comparable gasoline engine?
Non-turbo diesels lose less power in the Rockies
At least according to the SAE J1349 standard.
(Calculations shown below).
Assumptions
Dry air pressure in the Rockies = 90 kPa ( at 3000 ft)
...
- 39.1k
8
votes
Accepted
Ford Focus engine cuts out at 3000+ RPM
In this case replacing the fuel filter for new seems to have done the trick. I was able to find one for roughly £27 on eBay and fitted it myself in under 45 minutes. Thought I'd leave the information ...
- 381
8
votes
Accepted
Can diesel engine be harmed as easily as gasoline engine by over-revving?
The rev limit of a petrol (gasoline) engine is generally set to protect the internals of the engine. Less sporty engines are designed to a cost and their components may not have the strength or ...
- 1,698
8
votes
2004 powerstroke white smoke now no start
I'm not a diesel mechanic but after a quick search the number one cause of no starts on the 6.0 is lack of oil pressure. The injectors need 500psi minimum to operate.
This indicates there is not ...
- 10.7k
8
votes
Does free revving a diesel engine to 4000 rpm (1.6 crdi- hyundai) cause any damage?
Short answer - no. It's perfectly okay. And , it's also perfectly okay to be annoyed. It's one of those things mechanics like to do (no offence to anyone). Similar to endlessly hitting refresh on a ...
- 2,196
Only top scored, non community-wiki answers of a minimum length are eligible