From Mercedes Wiki

The Mercedes-Benz DiesOtto is an experimental Automobile engine that “is said to incorporate the benefits of a diesel engine, but runs on regular old unleaded.”^[1]

Its name is a Portmanteau of Diesel and Otto, referring to the Diesel engine, first introduced by German engineer Rudolf Diesel, and the Otto cycle, as a reference to Nicolaus Otto (even though the invention of the Gasoline engine is variously attributed to both Nicolaus Otto and Alphonse Beau de Rochas).

Contents 1 Engine characteristics and principles of operation 1.1 Testing and demonstration 2 References 3 External links

Engine characteristics and principles of operation

The concept engine has an in-line, four-cylinder configuration and displaces 1.8 litres. Its peak power is no less than 175 Kilowatt (235 Horsepower), making its specific output 97 kW/L (130 hp/L), and its peak torque is 400 N·m, making its specific torque 220 N·m/L. Mercedes-Benz do not specify the RPM at which these specified maxima are reached.^[2]

The DiesOtto features the following:

• HCCI (Homogeneous Charge Compression Ignition);
• Variable valve timing;
• Turbocharger;
• Variable compression ratio;
• Gasoline direct injection.

It also uses a starter-alternator to reduce fuel consumption. The starter-alternator replaces the engine's Flywheel, and allows the engine to be started instantaneously so that it can simply stop when not needed, such as at traffic lights, and smoothly re-start when needed.

In low-demand conditions (low to medium engine speeds), the engine uses HCCI. In high-demand conditions, it operates like a regular gasoline engine (using spark ignition of the fuel/air mixture) and uses the full benefits of direct fuel injection, turbocharging and variable valve timing to maximize efficiency. These two modes of operations require different compression ratios, achieved via a concept similar to that of the Frederick W. Lanchester,^[3] which is why the engine also features a variable compression ratio.

It is reported to consume less than 6 Litre/100 Kilometre (47 Fuel economy in automobiles_{-Imperial unit}; 39 Fuel economy in automobiles_{-United States customary units}) in the body of an S-Class. However, it is unknown in what conditions this mileage is achieved. Nevertheless, these figures are only bested by the smallest diesel engines on sale in Europe, and in far smaller cars than the S-Class.

Testing and demonstration

The testing and demonstration vehicles include a long-wheel based Mercedes-Benz S-Class fitted with a 19 bhp (14 kW) electric motor to hide the transition from spark to compression power, and the engine has been installed in the Mercedes-Benz F700 concept car shown at the 2007 Frankfurt Motorshow.^[3]

References

External links

• Pictures for Mercedes concept DiesOtto Car