Petroleum 101

Motoring and transportation related discussions.
Forum rules
The global forum rules are found here.

NOTE: posts in this section are not counted towards your total.
RuadRauFlessa
Registered User
Posts: 20576
Joined: 19 Sep 2003, 02:00
Location: Bloodbank

Re: Petroleum 101

Post by RuadRauFlessa »

:rock: :rock: :rock: :rock: :rock: :rock: :rock: :rock: :rock: :rock:
Spoiler (show)
Intel Core i7-2600k @ 3.4GHz
Corsair Vengence 2x4GB DDR3 2000MHz
Thermaltake Toughpower 850W
ASUS nVidia GTX560 1GB
CoolerMaster HAF 932
Anakha56
Forum Administrator
Posts: 22136
Joined: 14 Jun 2004, 02:00
Processor: Ryzen 1700K
Motherboard: Asus X370
Graphics card: Asus 1060 Strix
Memory: 16GB RAM
Location: Where Google says

Re: Petroleum 101

Post by Anakha56 »

Petrol = Gas...

/According to the Americans...
JUSTICE, n A commodity which is a more or less adulterated condition the State sells to the citizen as a reward for his allegiance, taxes and personal service.
User avatar
Tribble
Registered User
Posts: 88465
Joined: 08 Feb 2007, 02:00
Processor: Intel Core i7-4770K CPU@3.50GHz
Motherboard: ACPI x64-based PC
Graphics card: GeForce GTX 780 Ti
Memory: 16GB
Location: Not here
Contact:

Re: Petroleum 101

Post by Tribble »

How can it be - it is a liquid. ;-)
Image
Hman
Registered User
Posts: 28520
Joined: 06 Oct 2003, 02:00
Processor: Intel i5 650
Motherboard: Asus P7H55-M LX
Graphics card: Gigabyte 7850 2GB OC
Memory: 8GB Kingston DDR3
Location: In my skin
Contact:

Re: Petroleum 101

Post by Hman »

RuadRauFlessa wrote:...Autoignition is also causes an effect known as pinging. Due to the fuel igniting the oil on the inside of the barrel is burned away and then causes extra friction and heat when the piston does have to travel. This causes extra strain on the connecting rods and the crank shaft (which in turn also lowers performance).
Autoignition, detonation, and pinging are three names for the same phenomenon, which is a uncontrolled, undesirable situation where the air/fuel mixture spontaneously combusts with explosive force greater than the "slow" burn of proper ignition. (Oil get's burned off from the cylinder sleeve in any case, detonation has no special effect there, and no extra friction.)

Detonation can be brought on with any of the following conditions:

a) The compression pressure is to high for the fuel in use
b) The ignition timing is too early
c) A combination of high compression and early ignition timing
EDIT: d) A air/fuel mixture that is too lean can also result in detonation

The explosive force of detonation coupled with the high heat output thereof deforms the surfaces of the piston, valves and head (cylinder liners are normally too hard to be damaged directly). Debris forms and results in even more damage as the piston strikes them into the head and valves.

The high forces of the detonation also increases wear on the bearings of the crankshaft.
RuadRauFlessa wrote:It is worth noting that even in vehicles considered as low performance the difference between 93 and 95 will be noted. Better fuel economy and increased performance.
Now as to why some vehicles might se better performance / mileage.

On today's vehicles the engines are designed to run on a certain grade of fuel, but the advanced engine management systems have no way of knowing what fuel is in use, what they can figure out though is if the engine is detonating via the use of a knock sensor. So in the case of a engine with a high compression ratio designed for say high octane fuel and the drivers fills with a lower octane / quality fuel and the ECU detects detonation it will retard ignition timing untill detonation stops. Obviously retarding ignition timing results in weaker performance and as a result worse fuel economy. Vehicles with lower compression ratios normally stick to their designed operation as dictated by the ECU regardless if a higher octane fuel is used thus giving no benefit, other's might periodically advance the ignition timing (within manufacturer specifications) to check for detonation, if none is detected it might use the advanced timing (increasing performance and fuel economy) until such time as knock is detected.

This obviously depends on design specifications form the manufacturer.

Older vehicles with more primitive ignition systems will see no difference between differing octane graded fuels, thus the need to run only the specified fuel ratings as per the manufacturer.
Last edited by Hman on 29 Aug 2011, 12:22, edited 1 time in total.
"Every thinking man is a drinking man."


Member of the Barberton Tigers
User avatar
Tribble
Registered User
Posts: 88465
Joined: 08 Feb 2007, 02:00
Processor: Intel Core i7-4770K CPU@3.50GHz
Motherboard: ACPI x64-based PC
Graphics card: GeForce GTX 780 Ti
Memory: 16GB
Location: Not here
Contact:

Re: Petroleum 101

Post by Tribble »

In an Engine Management System (EMS), electronics control fuel delivery, ignition timing and firing order. Primary sensors on the system are engine angle (crank or Top Dead Center (TDC) position), airflow into the engine and throttle demand position. The circuitry determines which cylinder needs fuel and how much, opens the requisite injector to deliver it, then causes a spark at the right moment to burn it. Early EMS systems used analogue computer circuit designs to accomplish this, but as embedded systems became fast enough to keep up with the changing inputs at high revolutions, digital systems started to appear.

Some designs using EMS retain the original coil, distributor and spark plugs found on cars throughout history. Other systems dispense with the distributor altogether and have individual coils mounted directly atop each spark plug. This removes the need for both distributor and high-tension leads, both components with a poor record for long-term reliability.

Modern EMSs read in data from various sensors about the crank position, manifold temperature, manifold pressure (or air mass flow), throttle position, fuel mixture via the O2 sensor and sometimes the unit will read data from knock sensors and exhaust gas temperature sensors. The EMS then uses collected data to precisely determine how much fuel to deliver and when and thus how far to advance the ignition timing. With electronic ignition systems, individual cylinders[citation needed] can have their own individual ignition timing so that timing can be as aggressive as possible per cylinder without fuel detonation. As a result, sophisticated electronic ignition systems can be both more fuel efficient, and produce better performance, over their counterparts.
From : http://en.wikipedia.org/wiki/Ignition_s ... c_ignition
(yes - I am clueless and needed wiki for this)

So this explains why my car likes the higher octane of 95 :D
And this is how you know my car uses the EMS mentioned above
Image
User avatar
Stuart
Lead Forum Administrator
Posts: 38503
Joined: 19 May 2005, 02:00
Location: Home

Re: Petroleum 101

Post by Stuart »

WiK1d wrote:You all are yammering on about 93 vs. 95 when Stuart didn't even use the correct term. Petroleum != Petrol
Lol
Image
GreyWolf
Registered User
Posts: 4754
Joined: 06 Aug 2003, 02:00
Processor: PHENOM II 945
Motherboard: Asus M4A78
Graphics card: HIS ICEQ 4850 1GB
Memory: 4GB CORSAIR XMS II 1066
Location: , location, location!

Re: Petroleum 101

Post by GreyWolf »

RTFM

My manual says to use 98 or 95. So 95 it is then.
"Every normal man must be tempted at times to spit on his hands, hoist that black flag, and begin slitting throats."
- H. L. Mancken
User avatar
THE_STIG
Spoiled Brat
Posts: 11762
Joined: 26 Aug 2010, 20:33
Processor: Core i7 6800k
Motherboard: Asrock x99 taichi
Graphics card: Zotac 1080ti amp extreme
Memory: 16gb(4x4gb) corsair vengeance
Location: Some say.......

Re: Petroleum 101

Post by THE_STIG »

I would just like to know how much difference 95 makes to the fuel consumption. I hear people saying you get 80km more from 95, but is this true.

I currently use 93, and have a 1999 Mercedes C180 classic. So far I have worked out that it is doing 7.5L/100km as about 80% of the 600km I do per week is on the highway. So I am just wondering if it would make more sense to use 95?
WiK1d
Registered User
Posts: 20732
Joined: 13 Sep 2004, 02:00
Location: Cruising the streets of Pretoria
Contact:

Re: Petroleum 101

Post by WiK1d »

80km extra on what? If I got 80km extra on my bike I'd get half extra, right...
SykomantiS
Registered User
Posts: 14085
Joined: 06 Oct 2004, 02:00
Location: Location, Location...
Contact:

Re: Petroleum 101

Post by SykomantiS »

Stig, it all depends on the motor. But even then, 80km is really, and I do mean really pushing it.
Newer cars with higher compression ratios stand more to gain from 95 than older vehicles. I suggest reading through the whole thread to understand why.

It's like my one buddy telling me they get 100km more on a tank of BP 50ppm over other brands of diesel. So I'm testing it. Iv'e been really careful, extra careful to point of giving this tank of BP diesel an unfair advantage over the rest (by way of driving style), and so far I'm seeing exactly ZERO improvement. :| Having said that, the tank only dropped beneath half this afternoon, so time will tell. Let's just say I'm not expecting any miracles.
SykomantiS
Registered User
Posts: 14085
Joined: 06 Oct 2004, 02:00
Location: Location, Location...
Contact:

Re: Petroleum 101

Post by SykomantiS »

WiK1d wrote:80km extra on what? If I got 80km extra on my bike I'd get half extra, right...
What'd you mean half extra? :scratch:
Trumpets can surely do more than 200km on a tank?
(Ok, maybe not on a track...? But really- that thirsty??)
WiK1d
Registered User
Posts: 20732
Joined: 13 Sep 2004, 02:00
Location: Cruising the streets of Pretoria
Contact:

Re: Petroleum 101

Post by WiK1d »

On the little Derbi. I don't care about economy on the Trumpet, I just want poweeeeeer!
User avatar
THE_STIG
Spoiled Brat
Posts: 11762
Joined: 26 Aug 2010, 20:33
Processor: Core i7 6800k
Motherboard: Asrock x99 taichi
Graphics card: Zotac 1080ti amp extreme
Memory: 16gb(4x4gb) corsair vengeance
Location: Some say.......

Re: Petroleum 101

Post by THE_STIG »

SykomantiS wrote:Stig, it all depends on the motor. But even then, 80km is really, and I do mean really pushing it.
Newer cars with higher compression ratios stand more to gain from 95 than older vehicles. I suggest reading through the whole thread to understand why.

It's like my one buddy telling me they get 100km more on a tank of BP 50ppm over other brands of diesel. So I'm testing it. Iv'e been really careful, extra careful to point of giving this tank of BP diesel an unfair advantage over the rest (by way of driving style), and so far I'm seeing exactly ZERO improvement. :| Having said that, the tank only dropped beneath half this afternoon, so time will tell. Let's just say I'm not expecting any miracles.
I see, I have just come back from the petrol station though. It took 54.4L to fill it up again and I have done 734Km since it was last filled.......so that gives me 7.35L/100Km. I am still very impressed with that considering that the car is 13 years old and has exactly 279 188km on the clock, the manual claims 7.2L/100Km on the open road.

I will try and find out what the engines compression ratio is.

//Edit: I found some info on the engine:
1.8L 16valve with DOHC, compression ratio is 9.6:1, 170Nm, 129Bhp.
And then I found this part on Wikipedia(yes I know :lol: )
Unlike the 102, 103, and early 104 series engines, the engine did not use mechanical injection but the Siemens PEC/PMS (Pressure Engine Control) management system, which integrates fuel and spark management.

It is a speed-density type of system, as mixture formation is dependent on RPM, TPS angle, and manifold pressure (MAP).

Injectors work in pairs (idle, part load), or altogether (full-load).

It uses 2 ignition coils and no ignition distributor. Cylinders are fired in pairs (dual fire) - 1 and 4 together, and 2 and 3 together. The crankshaft position sensor is sensing the movement of two radially opposed position plates on the flywheel, one of which is magnetized, and the other is not. Thus, the engine management has precise information which group of cylinders to fire, and which group of injectors to spray.

SykomantiS
Registered User
Posts: 14085
Joined: 06 Oct 2004, 02:00
Location: Location, Location...
Contact:

Re: Petroleum 101

Post by SykomantiS »

All well, and good. I'd take a guess and say you'd see better consumption on 93. Do you know if the engine has knock sensing capabilities?
User avatar
THE_STIG
Spoiled Brat
Posts: 11762
Joined: 26 Aug 2010, 20:33
Processor: Core i7 6800k
Motherboard: Asrock x99 taichi
Graphics card: Zotac 1080ti amp extreme
Memory: 16gb(4x4gb) corsair vengeance
Location: Some say.......

Re: Petroleum 101

Post by THE_STIG »

Yes, that it does have
SykomantiS
Registered User
Posts: 14085
Joined: 06 Oct 2004, 02:00
Location: Location, Location...
Contact:

Re: Petroleum 101

Post by SykomantiS »

Well, then you might try 95. If the onboard computer advances the timing enough, you might see some gains on 95 octane :)
User avatar
THE_STIG
Spoiled Brat
Posts: 11762
Joined: 26 Aug 2010, 20:33
Processor: Core i7 6800k
Motherboard: Asrock x99 taichi
Graphics card: Zotac 1080ti amp extreme
Memory: 16gb(4x4gb) corsair vengeance
Location: Some say.......

Re: Petroleum 101

Post by THE_STIG »

Will give that a try next time I fill up
Post Reply