Comments on: Homogeneous Charge Compression Ignition

By: Mercedes Benz F 700 with DIESOTTO engine

Mercedes Benz F 700 with DIESOTTO engine — Thu, 08 Nov 2007 07:27:41 +0000

[...] auto ignition or homogeneous combustion. I’ve previously blogged about homogeneous combustion here, so read up if you want to know more on [...]

By: jamsbong

jamsbong — Fri, 27 Jul 2007 08:14:33 +0000

To answer your question, why no spark plug? Easy, the incoming fuel is too dilute to be ignited by a spark. Remember, we need a ratio of 14:1 for spark ignition. Now, the engineers are trying to save fuel, reduce emissions, clean up environment, etcs…

The fuel coming in is probably 30 or 40:1 ratio. then add a slight touch of injected fuel into a hot chamber and boom! we have ignition.

By: Mercedes Benz DiesOtto inline-4 engine concept

Mercedes Benz DiesOtto inline-4 engine concept — Wed, 25 Jul 2007 21:59:44 +0000

[...] ignites the air-fuel mixture through compression alone without spark ignition – this is called homogeneous combustion. For better emissions, the DiesOtto engine has a standard three-way catalytic [...]

By: Volkswagen sneak preview of new engine projects

Volkswagen sneak preview of new engine projects — Tue, 10 Jul 2007 19:42:31 +0000

[...] system, but at medium to high engine speeds conventional spark ignition is used. This is similar to Honda’s Activated Radical Combustion technology, which also works at relatively lower engine speeds of below [...]

By: pavithran

pavithran — Sun, 29 Apr 2007 21:16:59 +0000

cacing said,
April 17, 2007 @ 9:33 am
Iâ€™m probably not understanding it correctly, but referring to the last paragraph, if we introduce a second fuel of lower octane, that would then disqualify this process from being completely HCCI, as the lower octane fuel will have to burn first, then propagate the flame front to the rest of the air-fuel mixture. If thatâ€™s the case, why bother putting a second fuel type, when the same can be done with a spark plug?
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Agree with you here. Plus, introducing another low octane fuel also means that the car has to cary different octane ratings of fuel at any one time. Complicates stuff too much.

By: Charger

Charger — Tue, 17 Apr 2007 08:25:30 +0000

Yet another stunt from Honda.

By: proton GL

proton GL — Tue, 17 Apr 2007 08:19:53 +0000

cold start combustion is easily resolve with some kind initial ignition, or glow plug, etc.
my doubt is the capabilty for higher speed engine, theres a posibility a preignition happened before TDC due to heat built up, which destruct the engine,
due to non regulated ignition, they might want to have somekind of variable copression ratio in relation with engine speed or load, perhaps a small clyinder/piston built in the chamber to alter volume of the chamber hence the reduce the comp ratio for extreme condition,

By: aesthari

aesthari — Tue, 17 Apr 2007 07:48:38 +0000

Yea, agree with cacing there, so no spark plugs are used, but the ignition is still localised at first, not spontaneously for the whole area.

By: kei9

kei9 — Tue, 17 Apr 2007 06:54:13 +0000

still……we need alternatives to fossil fuel! H2O for exact.

By: cacing

cacing — Tue, 17 Apr 2007 01:33:15 +0000

I’m probably not understanding it correctly, but referring to the last paragraph, if we introduce a second fuel of lower octane, that would then disqualify this process from being completely HCCI, as the lower octane fuel will have to burn first, then propagate the flame front to the rest of the air-fuel mixture. If that’s the case, why bother putting a second fuel type, when the same can be done with a spark plug?

By: LittleFire85

LittleFire85 — Tue, 17 Apr 2007 01:16:17 +0000

At last a petrol engine without spark plugs.. Wow.. but i can predict this engine will have more torque but less hp.. since it can only have 4,000rpm only… anyways this new engine can help improve the fuel consumption on city driving and cruising.. Cheers!