DLR reinvents the Stirling engine

[I Citro]

A news published on elector the 09 / 03 / 2007 (subscriber access) talks about this innovation:



He put the time engine (multi-fuel) at a time ...
In wizards of annealed bread, a German team designed an internal combustion engine based on the principle of a linear generator with free piston to power the electric motor of a car. A novelty inspired by a patented 1816 engine.

Researchers from the German Aerospace Center (DLR) have produced a new internal combustion engine based on the principle of a linear free-piston generator. This technique, more or less inspired by the stirling engine that has never had the chance to be successful, allows to design an engine capable of transforming any type of fuel (gasoline, natural gas, hydrogen or ethanol) into electrical energy, without the losses of efficiency usually encountered. The crankshaft of a traditional engine is replaced by a linear generator and a pneumatic spring. The generator directly produces electrical energy that can be used to propel a vehicle by means of an electric motor. The compression ratio and engine displacement being variable, its operation in reduced power is highly optimized. This reduces the engine consumption, as well as its polluting emissions, especially when used at low speeds as is the case when traveling in the city. According to researchers, this new engine should be on the market by 5 to 6 years ago.
Let's hope that this good idea will not suffer the same fate as the engine of the brothers Jarret, inspired by the same concept but which never knew the slightest echo, probably for lack of opportunities at a time when the oil seemed inexhaustible. Indeed, if the energy efficiency seems particularly attractive thanks to the absence of unnecessary friction caused by a traditional mechanical cumbersome, it is realized that there is an impressive amount of adjustments to be made before claiming to operate such a motor in the automobile industry.

Et here the original link in German.

[Leo Maximus]

Maybe the heat engine of a future hybrid car?

The Jarret engine was the subject of an article in Science & Vie n ° 747 of December 1979:

[elephant]

When is the bike powered by a Jarret motor ???

[Remundo]

Hello friends,

Translation of the article for non-Germanists

http://www.dlr.de/desktopdefault.aspx/tabid-1/86_read-7302/

Caption: Justage der Kühleinrichtung: adjustment of the cooler
Blick aus der Messwarte: Visual inspection of test technicians

Stuttgart. --
An engine that can be operated with different fuels, with optimal combustion, conversion to electrical energy - this waiting for modern transmission in transport drives the Institute's scientists for vehicle concepts at the German Center Technology and Aeronautics (DLR Deutschen Zentrum für Luft- und Raumfahrt). Inspired by a free piston engine patent, engineers are developing a state-of-the-art unit for high performance in future vehicles.

Automakers are responding to the depletion of oil and gas reserves with many improvements for conventional transmissions, but also with proposals for new concepts such as hybrid and new transportation fuels such as ethanol and diesel. Biodiesel, recently introduced on the market. Stuttgart scientists are now launching an effective solution for the various challenges of the car of the future.

When considering the benefits of this technology, conventional internal combustion engines have significantly higher efficiency prospects while also reducing fuel consumption. Strong point of the concept: The crankshaft of a conventional engine is replaced by the combination of a linear generator and a gas management. The generator produces directly electrical energy which is in turn converted by an electric propulsion motor, possibly housed in motor-wheels.

Thanks to this idea and for the first time, DLR-Institut engineers are building a combustion engine with a variable compression ratio and a variable displacement. The combustion management is flexibly adapted for any engine load. Thanks to the previous free piston linear generators, various fuels, such as gasoline, natural gas, hydrogen or Ethanol can be used (Flexfuel approach) without experiencing significant performance losses traditionally encountered in engines single-fuel, for example natural gas type or pure gasoline.

The variable compression ratio of the gas mixture has another advantage: The behavior of the vehicle in urban uses is optimized and the engine efficiency is increased. For more common traffic situations, the engine load can also be much more varied and efficient, especially on the highway.

At the DLR-Institute for Transport Technologies, the management of gases and the linear electric generator are ideal possibilities for testing this new transmission. During the tests, the combustion conditions, the linear generator, the motor breathing can each be checked with the electronic control, then the entire engine can be put to the test. In addition to the previously mentioned advantages for efficiency and consumption, the system is virtually maintenance-free since all parts can operate without lubricating oil.

According to the inventors, this system will only mature for the market in five to six years. For future uses, dialogue with the transport industry is already under way.

Broader applications of the system are planned: APUs (Auxiliary Power Units) and also stationary stationary energy production.

Interesting technology indeed in the sense that it removes the archaism of the crankshaft and the "friction piston" because the connecting rod has a radial component force on the piston.

But I'm not sure that the linear generators are as good as we want to believe, especially to control the movement of the pistons ...

The problem of combustion management (variable compression ratio, operating the chambers at a thermodynamic optimum (full load) with a variable displacement) is on the other hand well posed by the DLR and largely resolved by the concept PRBC "full option" (variable timing valves + compression ratio adjustment pistons + targeted deactivation of chambers for partial engine loads)

@+

[elephant]

Anyway, this is only a first step and I suppose that we will be able to "electronicize" these engines as we do now for our (too) expensive cars ....

[Leo Maximus]

Anyway, this is only a first step and I suppose that we will be able to "electronicize" these engines as we do now for our (too) expensive cars ....

Sure, the electronification brings a lot but the computerization is the essential. Most of the patents filed by Toyota for the Prius are patents on HSD Hybrid System Management algorithms, it took an 32 bits processor. And after it is said that Japanese cars are reliable because there is no electronics on board.

[lv13r]

this engine looks like pascara
http://www.pateras-pescara.net/moteurs_ ... ibres.html
it will work well for cogeneration and electricity
hey christopher the heat pump coupled to the exhaust using a gas turbine
besides asser easy to build at present (there are only cylinders)
this engine was used during the war on the German submarine to compress the air in the torpedo launchers
I had seen an article about a popular 1955 mechanics
if I find it I scans the article
he was even built a locomotive (named belfegore) that operated in France
but the pb of motor and the infernal noise of his escape
LV13R

[Leo Maximus]

this engine looks like pascara
http://www.pateras-pescara.net/moteurs_ ... ibres.html
it will work well for cogeneration and electricity
hey christopher the heat pump coupled to the exhaust using a gas turbine
besides asser easy to build at present (there are only cylinders)
this engine was used during the war on the German submarine to compress the air in the torpedo launchers
I had seen an article about a popular 1955 mechanics
if I find it I scans the article
he was even built a locomotive (named belfegore) that operated in France
but the pb of motor and the infernal noise of his escape
LV13R

It's the same principle and the Jarret engine (and the others) were inspired by this system which was a compressor at the start. Too bad that this idea was not taken on hybrids like Kangoo ER for example.

[lv13r]

hello maximus leo
well yes there must be a problem somewhere, because this kind of compressor motor (I'm talking about the pascara) must be "fairly" easy to manufacture and must be less expensive in production than a thermal crankshaft
moreover it does not vibrate or very little and its output is superior to a crankshaft engine (at least it is claimed)
on the other hand I am never found anything on the gas turbine that had equipped these engine compressor
and you will have doc on it ????
LV13R

[Remundo]

The bottom line is that a gas turbine is designed for a nominal continuous flow, while the pistons tend to give periodic puffs and not always the right temperature and the proper gas flow.

This system is hardy and can burn less noble fuels (diesel for example), but does not have a better performance than a gas turbine equipped with a gas or kerosene burner or better, natural gas.