DiesOtto
Encyclopedia
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.”
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).
The DiesOtto features the following:
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 Lanchester shaft, which is why the engine also features a variable compression ratio.
It is reported to consume less than 6 L/100 km when fitted to the S-Class demonstration vehicle. 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.
fitted with a 19 bhp 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.
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
DiesOtto is an experimental automobile engine that “is said to incorporate the benefits of a diesel engine, but runs on regular old unleaded.”
Its name is a portmanteau of Diesel and Otto, referring to the Diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
, first introduced by German engineer Rudolf Diesel
Rudolf Diesel
Rudolf Christian Karl Diesel was a German inventor and mechanical engineer, famous for the invention of the diesel engine.-Early life:Diesel was born in Paris, France in 1858 the second of three children of Theodor and Elise Diesel. His parents were Bavarian immigrants living in Paris. Theodor...
, and the Otto cycle
Otto cycle
An Otto cycle is an idealized thermodynamic cycle which describes the functioning of a typical reciprocating piston engine, the thermodynamic cycle most commonly found in automobile engines....
, as a reference to Nicolaus Otto
Nicolaus Otto
Nikolaus August Otto was the German inventor of the first internal-combustion engine to efficiently burn fuel directly in a piston chamber. Although other internal combustion engines had been invented these were not based on four separate strokes...
(even though the invention of the gasoline engine is variously attributed to both Nicolaus Otto and Alphonse Beau de Rochas).
Engine characteristics and principles of operation
The concept engine has an in-line, four-cylinder configuration and displaces 1.8 litre. Its peak power is no less than 175 kW, 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.The DiesOtto features the following:
- homogeneous charge compression ignition (HCCI);
- variable valve timingVariable valve timingIn internal combustion engines, variable valve timing , also known as Variable valve actuation , is a generalized term used to describe any mechanism or method that can alter the shape or timing of a valve lift event within an internal combustion engine...
; - twin variable geometry turbochargingTurbochargerA turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...
; - variable compression ratioVariable compression ratioVariable compression ratio is the technology to adjust internal combustion engine cylinder compression ratios on the fly. This is done to increase fuel efficiency while under varying loads. Higher loads require lower ratios to be more efficient and vice versa. Variable compression engines allow for...
; - direct fuel injectionGasoline direct injectionIn internal combustion engines, gasoline direct injection , also known as petrol direct injection or direct petrol injection, is a variant of fuel injection employed in modern two-stroke and four-stroke gasoline engines...
.
It also uses a starter-alternator to reduce fuel consumption. The starter-alternator replaces the engine's flywheel
Flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...
, 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 Lanchester shaft, which is why the engine also features a variable compression ratio.
It is reported to consume less than 6 L/100 km when fitted to the S-Class demonstration vehicle. 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-ClassMercedes-Benz S-Class
The Mercedes-Benz S-Class is a series of luxury sedans produced by Mercedes-Benz, a division of Daimler AG. The classification was officially introduced in 1972 with the W116 S-Class, which succeeded previous Mercedes-Benz models dating to the mid-1950s...
fitted with a 19 bhp electric motor to hide the transition from spark to compression power, and the engine has been installed in the Mercedes-Benz F700
Mercedes-Benz F700
The Mercedes-Benz F700 is a concept car produced by Mercedes-Benz. It was first revealed to the public at the 2007 Frankfurt motor show.-DiesOtto engine:...
concept car shown at the 2007 Frankfurt Motorshow.