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Wednesday, April 30, 2008

Hemp Oil - drive the ELSBETT engine

millions of acres of unused agricultural land could be planted with hemp
and millions of cars could run on the extremely frugal elsbett motor.
Rudolf Diesel, the inventor of the DIESEL engine, intended his engine to
run on vegetable oil ... and then he died mysteriously aged 55 ...

1893 Rudolf Diesel invents the Diesel engine. infoPortrait Rudolf Diesel Rudolf Diesel
1900 Rudolf Diesel is awarded the Grand Prix for his engine at the World Exhibition in Paris .
1913 On September 29th, Rudolf Diesel mysteriously disappears at the age of 55 whilst crossing the English Channel from Antwerp to Harwich.

1985 ELSBETT piston technology and ELSBETT cooling concept (using oil instead of water)

Soviet Union licenses the ELSBETT engine concept (3 cylinder car engine with direct injection) with multiple fuel capability and integrated injection system (unit-injector principle).

2003 Elsbett introduces DIY converters for cars and lorries.

While in a conventional diesel engine with a precombustion chamber approximately 31% of the energy contained in the fuel is removed from the engine through the cooling system and dispelled into the radiator, (26% in direct injection diesel engines, 28% in petrol engines), in the case of the ELSBETT engine only around 14% to 16% of the heat has to be removed.

This reduced demand for cooling makes it possible to dispense with conventional cooling systems. In ELSBETT engines the cooling process is carried out by the engine's lubricating oil alone. Water radiators and air-cooling devices are thus dispensed with, and this reduces the number of parts, the weight and the volume of the engine.

The absence of water in the engine makes it possible to cast ribless blocks and to dispense with the head joint. Cracks in engines are more often the result of accentuated temperature gradients rather than the temperature itself. For this reason oil allows for the safer cooling of the engine as it works beyond the boiling point of water and reduces thermal tensions in the engine. Oil does not boil easily, does not cause internal corrosion or cavitation, does not freeze, and quickly reaches its working temperature.

The lower part of the piston is cooled by means of jets of oil. The jets of oil cool the internal walls of the cylinder and, guided by vanes fitted inside the piston body, reach the lower base of the piston head thereby cooling it. The engine head is cooled by means of the forced circulation of the oil. The oil itself is cooled by an external radiator.

In terms of energy, ELSBETT engines in the seventies and eighties performed better than conventional engines having an efficiency of approximately 40% to 43%. This increased performance was made possible by improving the thermal balance of the engine, causing greater availability of useful mechanical energy and substantially reducing the conversion of energy into useless heat. As the surface of the combustion chamber wall is reduced in size, and thermal insulation is caused by the excess air surrounding the combustion area, the heat flow and the cooling requirements are minimised.

DI Combustion Chamber Design


Large slow running DI engines (under 1500 rpm) have 'open chambers' where the piston has a very shallow dish shaped with a bump in the middle. Air movement is minimal and the multi hole injectors (often 8-12 hole) are set to inject a fine mist into the dish. Due to the size of the combustion chamber sufficient air is present to supply the fuel with oxygen and the fuel combusts before it contacts surfaces of the combustion chamber.


With smaller higher speed engines it is not possible to produce injectors with the multiple very small holes that would be necessary to provide sufficient fuel distribution. The number of holes is therefore reduced (3-5 hole). To achieve better fuel/air mixing air turbulence is induced within the combustion chamber.

Incoming air is set into rotation by the inlet valve being positioned to one side of the cylinder head. The air rotates around and down the cylinder as it is pulled in. This rotational force is sometimes increased by having a helical induction port passage where the air is guided into a semi-vortex swirl around the valve stem on its way into the cylinder.

The piston has a bowl in its crown. As the piston approaches the top of the cylinder the rotating air is forced into the piston bowl. The rotational force is magnified by the reduced diameter of the piston bowl. Thin, deep bowls have a higher swirl rate.

At the same time air squish is initiated as the air is forced from above the piston crown in towards the centre of the piston. The squish forces meet at the centre of the cylinder and oppose each other being forced downwards into the bowl where they follow the bowl profile being led into a horizontal swirl.

Simple bowl showing squish action - also described as torodial.

In order for the fuel and air to mix the fuel injection is set to spray against the wall of the piston bowl. The drag created by this contact stops the combusting fuel spray being dragged with the swirl and allows the fuel to contact with fresh oxygen. With thin bowls the spray does not have to penetrate as far to reach the combustion chamber wall so a wider more fine injection can be utilised that will mix more readily with the fuel.

With the quickest engines large air movement is required to give a fast mix. The fuel spray has to be more penetrating to overcome the increased air forces and the injection event rate is increased so that the fuel charge is swiftly delivered and has longer to mix and combust.

A trick used by several engine manufacturers is to give the bowl a lip to prevent the air squish motion pushing fuel above the piston crown, so that the majority of the fuel charge is mixed and burnt within the bowl. The lip also creates further micro turbulence within the bowl. Engines with this re-entrant lip design include VW/Audi tdi engines (thanks to John O for this info), Perkins Prima, Perkins 42482 and some Isuzu square (when looking from above) bowl chambers. The square chamber produces micro turbulence from its rounded corners which provide superior air-fuel mixing.

Perkins Squish Lip Re-Entrant Bowl Piston

Isuzu Square Bowl Piston

Chevy Duramax Piston (Cheers JMJ)
The Elsbett Piston

The Elsbett engine has a deep bowl which has a slight lip. The main difference is that the fuel charged is injected in such a manner as to 'blend perfectly with the air' and combust within a central core of hot air, not contacting the chamber walls, which is necessary for good air/fuel with other designs examined.

The MAN M system (film) combustion chamber

A similar shaped piston bowl to the Elsbett system. With this design the fuel is injection is directed onto the chamber wall where it spreads as a film, combusting as the film evaporates due to the heat of the piston. The heat of the piston has to be within a temperature range to achieve fuel evaporation without causing thermal decomposition and carburizing of the fuel.

Lessons to be learnt for Veg Oil

To summarise I would presume:-

Quick injection rate gives more time for the oil to begin to combust.

Chamber shapes that create greater micro turbulence - the Isuzu square chamber would appear superior in this respect - should provide better fuel air mixing and faster combustion.

Deep re-entrant chambers should be more effective than shallow chambers.

Comments, suggestions or observations will be gratefully received from those with relevant experience or information.

'Advanced Engine Technology' by Heinz Heisler ISBN 0-340-56822-4


Diesel was born in Paris, France, in 1858 as the second of three children to Theodor and Elise Diesel. Diesel's parents were immigrants living in France according to a biographical book by John F. Moon. Theodor Diesel, a bookbinder by trade, had left his home town of Augsburg, Kingdom of Bavaria, in 1848. He met his wife, Elise Strobel, daughter of a Nuremberg merchant, in Paris in 1855 and himself became a leathergoods manufacturer there.

Diesel spent his early childhood in France, but as a result of the outbreak of the Franco-Prussian War in 1870, the family was forced to leave and immigrated to London. Before the end of the war, however, Diesel's mother sent 12-year-old Rudolf to Augsburg to live with his aunt and uncle, Barbara and Christoph Barnickel, so that he might learn to speak German and visit the Königliche Kreis-Gewerbsschule or Royal County Trade School, where his uncle taught mathematics.

At age 14, Rudolf wrote to his parents that he wanted to become an engineer, and after finishing his basic education at the top of his class in 1873, he enrolled at the newly-founded Industrial School of Augsburg. Later, in 1875, he received a merit scholarship from the Royal Bavarian Polytechnic in Munich which he accepted against the will of his perennially cash-strapped parents who would rather have seen him begin earning money.

In Munich, one of his professors was Carl von Linde. Diesel was unable to graduate with his class in July 1879 because of a bout with typhoid. While he waited for the next exam date, he gathered practical engineering experience at the Gebrüder Sulzer Maschinenfabrik in Winterthur, Switzerland. Diesel graduated with highest academic honors from his Munich alma mater in January 1880 and returned to Paris, where he assisted his former Munich professor Carl von Linde with the design and construction of a modern refrigeration and ice plant. Diesel became the director of the plant a scant year later.

In 1883, Diesel married Martha Flasche, and continued to work for Linde, garnering numerous patents in both Germany and France.

In early 1890, Diesel moved his wife and their now three children Rudolf junior, Heddy and Eugen, to Berlin to assume management of Linde's corporate research and development department and to join several other corporate boards there. Because he was not allowed to use the patents he developed while an employee of Linde's for his own purposes, Diesel sought to expand into an area outside of refrigeration. He first toyed with steam, his research into fuel efficiency leading him to build a steam engine using ammonia vapor. During tests, this machine exploded with almost fatal consequences and resulted in many months in the hospital and a great deal of ill health and eyesight problems. He also began designing an engine based on the Carnot cycle, and in 1893, soon after Gottlieb Daimler and Karl Benz had invented the automobile in 1887, Diesel published a treatise entitled Theorie und Construktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschine und der heute bekannten Verbrennungsmotoren or Theory and Construction of a Rational Heat-engine to Replace the Steam Engine and Combustion Engines Known Today and formed the basis for his work on and invention of the Diesel engine.

Later life

Diesel decided that he did not like Benz's engine so he made his own engines. He tried to design an engine based on the Carnot Cycle. However, he gave up on this and tried to develop his own approach. Eventually he designed his own engine and obtained patent for his design. In his engine, fuel was injected at the end of compression and the fuel was ignited by the high temperature resulting from compression. In 1893, he published a book in German with the title "Theory and design of a rational thermal engine to replace the steam engine and the combustion engines known today" (English translation of the original title in German) with the help of Springer Verlag, Berlin. He managed to build a working engine according to his theory and design. His engine is now known as the diesel engine. Heinrich von Buz (1833-1918) was director (MAN AG) of an engine factory in Augsburg. From 1893-1897, he gave Rudolf Diesel the opportunity to test and develop his ideas according to the book by John F. Moon. Rudolf Diesel obtained patents for his design in Germany and other countries including USA, for example, US Patent 542846 and US Patent 608845.

In the evening of 29 September 1913, Diesel boarded the post office steamer Dresden in Antwerp on his way to a meeting of the "Consolidated Diesel Manufacturing Ltd." in London. He took dinner on board the ship and then retired to his cabin at about 10 p.m., leaving word for him to be called the next morning at 6:15 a.m. He was never seen alive again. Ten days later, the crew of the Dutch boat "Coertsen" came upon the corpse of a man floating in the sea. The body was in such a heavy state of decomposition that they did not bring it aboard. Instead, the crew retrieved personal items (pill case, wallet, pocket knife, eyeglass case) from the clothing of the dead man, which on October 13th were identified by Rudolf's son, Eugen Diesel, as belonging to his father.

1 comment:

gasump said...

Just as a point of interest re. the Elsbett cooling concept. In itself it is not a new idea.

The twin cylinder petrol engine which powered the Citroen 2CV is, despite many articles calling it 'air cooled', is in fact oil cooled. It is difficult to seeunless you know where to look. There's a small radiator/heat exchanger mounted behind the cooling fan.

It's a good concept for a small engine. Weight and complexity (thus production cost) is reduced, as well as servicing needs.

Oil cooling also gets around some of the problems caused by pure air cooling.