Wednesday 18th May 2005

Petrol & diesel to merge?

Mercedes plans common technology within a decade

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An end to pollution?

Mercedes is planning to revolutionise the internal combustion cycle by combining both diesel and petrol technologies into a single engine type. The company reckoned that it could achieve this within the decade, according to a report in this week's Autocar.

The company said that the components and technologies used in both types of engine are growing closer: common rail fuel injection and turbocharging are examples. The new types of engine will have no spark plugs and run on synthetic fuels; Mercedes has dubbed it the Diesotto, after Rudolph Diesel and Nikolaus Otto, who invented the four-stroke petrol engine.

The advantages from a constructor's point of view are that it will save duplicating components and help lower emissions, both costly items in an engine-builder's ledger.

• Autocar

[rizla]

Only took 200 years...

[philbob]

Yawn, known about that for a while. In fact Cambridge Uni and a few others are developing the technology, The problem is mainly because of the petrol. Common rail petrol injection is hard to engineer. If u think its easy and u can make it work within the next couple of years your going to be rich. It will be with us in the next five years I think. Petrol engines will become very powerfull.
It means that the engine's type will only be decided at the end of the production line. Thats what I understand anyway.

[wheeljack888]

This really is nothing new, and its the usual German triumph of marketing new but fairly conventional technology as something amazing. If anyone is seriously interested do a search on Homogenous Charge Compression Ignition (HCCI) engines, IIRC the HCCI concept is pre-war. I don't know of an OEM who isn't looking at this. The technology required for this has recently become available largely due to the rapid development of diesel engines, i.e advanced control systems for turbos, EGR and direct fuel injection.

[errek72]

wheeljack888 said:

This really is nothing new, and its the usual German triumph of marketing new but fairly conventional technology as something amazing. If anyone is seriously interested do a search on Homogenous Charge Compression Ignition (HCCI) engines, IIRC the HCCI concept is pre-war. I don't know of an OEM who isn't looking at this. The technology required for this has recently become available largely due to the rapid development of diesel engines, i.e advanced control systems for turbos, EGR and direct fuel injection.

Noted, but you must admit it is more exciting news to bring than the recent c-class facelift that was so dull and small that nobody actually noticed.

Not sure if this will be helpfull to environment or purse anyhow?

[bertie]

I thought Mercedes had already done this some years ago.

My wifes C class petrol certainly felt rough enough to be a diesel.

[pesmo]

So does this mean I will be able to do the following ?;

a/ put diesel in it
b/ put petrol in it
c/ put diesel in it then go to another pump and put some petrol as well (and it will work)
d/ put some hybrid special fuel in it ?

Is this technology a bit like that used in tanks that allows various fuels to be used ?

[Gentelman]

I like the sound of "synthetic fuels." They can already make diesel from soy and petrol from corn as well as synthetic motor oils (which only carry a 4 times greater risk of cancer), why not a fully synthetic gasoline?

[faniskapetanakis]

I think that the article is a bit misleading. As written in previous posts the article is referring to (or at least trying to) HCCI (Homogenous Compressed Charge Ignition or sth)technology. The combustion of the mixture is not performed by sparkplugs (like conventional petrol engines), but by compression. It's a bit like the diesel engine.
This kind of engine can run with stoich a/f ratios. Experiments have been made with 60-80:1.
Downside is that the temperature of the air entering the combustion chamber must be precisely controlled. A deviation of only 3-4 degrees Celsius is permitted (I think the figure is correct) otherwise there will be knock.
Another downside is that, up to now, HCCI engines work well only on full throttle. On partial throttle they tend to be pretty unstable.

I'm pretty sure that this technology will be mated with systems controlling valves independently (such as Lotus' Active Valvetrain), as valve control is of paramount importance in HCCI engines.

[jking]

Nothing new....VW worked on this concept 15 years ago, and Catapillar have working prototypes designed for the US market were you can fill the engine up with either fuel....ideally diesel for a CI engine, but as this is not so availible (in cities centres etc), is ok to run CI on gasoline!!

[sprinter885]

So--as I understand it if "within the decade" proves to be true
a) would that not give us just another 10 years of motoring on oil-based fuel before world reserves start looking dodgy?
b) If a) above is true would that mean Governments might fancy racking up unleaded fuel tax to the now higher (?) diesel rates to get a double wammy for last 10 years of oil?
c) in view of a) what the hell has Mighty M-B (Daimler Chrysler or whatever)been doing for past umpteen years?
d)At least BMW are working on Hydrogen cells..!!!!!

[V8 Archie]

Surely as PHers we should be asking about the likely figures from such an engine.

Are we talking a 2.5 with the torque of a 1.9 diesel lasting through the rev range of a 2.0 petrol? I can see how that might be fun.

[wedgie]

Certainly nothing new here - my old man designed a multi-fuel tank engine in the 1930s, and IMHO tanks have been able to run on just about anything since

[andymadmak]

A engine that runs on Dettol eh?
Should make for a cleaner, germ free environment!

Andy