The DiesOtto motor is an experimental

automobile engine There are a wide variety of propulsion systems available or potentially available for automobiles and other vehicles. Options included internal combustion engines fueled by petrol, diesel, propane, or natural gas; hybrid vehicles, plug-in hybr ...

that "is said to incorporate the benefits of a diesel engine, but runs on

gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

instead." Its name is a

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of ''Diesel'' and ''Otto'', referring to the

Diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...

, first introduced by German engineer

Rudolf Diesel Rudolf Christian Karl Diesel (, ; 18 March 1858 – 29 September 1913) was a German inventor and mechanical engineer who invented the Diesel engine, which burns Diesel fuel; both are named after him. Early life and education Diesel was born on 1 ...

, and the Otto cycle, as a reference to

Nicolaus Otto Nicolaus August Otto (10 June 1832 – 26 January 1891) was a German engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the modern internal combustion engine. The Associa ...

(even though the invention of the

gasoline engine A petrol engine (gasoline engine in American and Canadian English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as Autogas, liquefied petroleum gas and Common ...

is variously attributed to both Nicolaus Otto and Alphonse Beau de Rochas). As of 2017, the only company which announced to launch a car with a DiesOtto motor is

Mazda is a Japanese Multinational corporation, multinational automotive manufacturer headquartered in Fuchū, Hiroshima (town), Fuchū, Hiroshima Prefecture, Hiroshima, Japan. The company was founded on January 30, 1920, as Toyo Cork Kogyo Co., Ltd. ...

, with SKYACTIV-X.

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 , 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.Mercedes-Benz unveils DiesOtto - the "future of the gasoline engine"
/ref> The DiesOtto features the following: * homogeneous charge compression ignition (HCCI); *

variable valve timing Variable valve timing (VVT) is the process of altering the timing of a Poppet valve, valve lift event in an internal combustion engine, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combina ...

; * twin variable geometry turbocharging; * variable compression ratio; * direct fuel injection. It also uses a starter- alternator to reduce fuel consumption. The starter-alternator replaces the engine's

flywheel A flywheel is a mechanical device that uses the conservation of angular momentum to store rotational energy, a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, a ...

, and allows the engine to be started instantaneously so that it can simply stop when not needed, such as at traffic lights, and smoothly restart 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 operation require different compression ratios, achieved via a concept similar to that of the Lanchester shaft, which is why the engine also features a variable compression ratio. It is reported to consume less than when fitted to the S-Class demonstration vehicle. However, it is unknown in what conditions this mileage is achieved.

Testing and demonstration

The testing and demonstration vehicles include a long-wheel based Mercedes-Benz S-Class fitted with a

electric motor An electric motor is a machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a electromagnetic coil, wire winding to gene ...

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 Motor Show.

References

External links

Pictures for Mercedes concept DiesOtto Car
{{Webarchive, url=https://web.archive.org/web/20081015173030/http://www.automobilemag.com/multimedia/photo_gallery/0709_2007_mercedes_f700_diesotto_concept_photo_gallery/index.html , date=2008-10-15 Mercedes-Benz engines Automobile engines