Mercedes will debut F700 with DiesOtto engine at the Frankfurt Motor Show
Mercedes is bringing the green to the upcoming Frankfurt Motor Show with their new sedan concept car, the F700. Remember that DiesOtto engine that we told you about a while back? It's making its debut in this new luxury sedan. To refresh your memory, that engine produces 238hp and 295ft-lb. of torque from just 1.8 liters of displacement using some new technology known to many as homogeneous charge compression ignition, or HCCI, which "operates in compression ignition mode under light loads and spark ignition at other times" according to our own Sam Abuelsamid. The fuel mileage of the car with the DiesOtto engine is expected to be almost 40 miles per gallon, which is excellent for such a large vehicle.
The new F700 concept is just one of 18 vehicles that Mercedes is expected to showcase, including new Bluetec diesels and hybrids with both gasoline and diesel engines.
[Source: 4 Cars via Autoblog]
Reader Comments (Page 1 of 1)
Snark 4:54PM (8/10/2007)
Now, what I REALLY want to see is a sub-1.0L version of this sucker, around two or three cylinders and around 120hp, to power a series hybrid genset or provide clean performance for a small, lightweight sportster.
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rgseidl 2:17AM (8/12/2007)
If the F700 really is an Ocean Drive with a DiesOtto power plant, MB will steal absolutely everybody's thunder in Frankfurt. Especially if they announce a production date.
@ Snark -
remember that two- and three-cylinder engines have significantly worse vibration characteristics than inline fours. If you add inertial compensation systems, the additional expense and friction usually make them the less attractive option, except for motorcycles.
The one exception is SI engines with sequential turbos, because below a certain diameter you cannot obtain twin-scroll volute designs off the shelf. That means you're effectively limited to three cylinders per high high pressure turbo because you need thorough scavenging to run smoothly at low speeds when using conventional SI combustion.
The DiesOtto discussed here is a 1.8L inline 4 with sequential turbos. Perhaps Mercedes decided they could live with the crosstalk in the exhaust manifold because at low engine speed they run in HCCI mode anyhow, which implies high rates of hot EGR.
Equivalent boost in a single stage is feasible with a modern pressure wave supercharger (Hyprex),
This for-fee paper discusses a 1.0L inline 4 taken from an previous-generation VW do Brasil Gol and modified to deliver 100kW (135hp) of power and 200Nm of torque. An earlier generation of this exotic technology was briefly used by both Opel and Nissan but could not meet tightening emissions regs.
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rgseidl 2:27AM (8/12/2007)
Looks like ABG does not accept embedded HTML tags. Here are those references again:
http://www.wenko.ch/uploadfiles/EN_200057.pdf
http://www.all4engineers.com/index.php;site=a4e/lng=en/id=6003/alloc=3
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rgseidl 2:28AM (8/12/2007)
Correction: PWSC were used in production LDVs for the Japanese market by Mazda not Nissan.
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Dr. K. Zaidi 10:58AM (10/19/2007)
Indeed DI-HCCI engine is possible that does not require any spark plug unlike Merceds-Benz F700 engine.
This engine could be as small as that of a small car engine but with a very high power density something 150PS/Lit.
Please have a look of our most recent contribution
SAE-Paper Number 08PFL-925
Development of a Direct Injection-Homogeneous Combustion Compression Ignition (DI-HCCI) Heavy Duty DiesOtto Engine
K. Zaidi
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