The German built Elsbett diesel engine is designed to run on vegetable oil the way Rudolf Diesel intended.
The Elsbett company goes back to the 1930's. Their diesel engine devolped in the 1980's (way before todays Green movement) was designed to run on vegetable oil. This engine is oil cooled. Here is some more info lifted from their site.
I learned my IDI losses 30% of its total fuel energy to the coolant system. This makes it a perfect candidate for waste heat energy recovery. The Elsbett engine only losses about half that.
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The distinctive features afforded by the ELSBETT technology, and which relate to specific engine components, are listed below. Each component part can be used separately and many of today's best-known engines are already fitted with components or systems designed by ELSBETT.
1. The ELSBETT articulated piston
2. The ELSBETT oil cooling system
3. The ELSBETT fuel injection system
4. The ELSBETT duothermic combustion system
Only by combining the above mentioned elements is it possible to achieve the optimum thermal and mechanical conditions required for the combustion of fuels, such as natural vegetable oils, which are slow to vaporise.
The only engine specifically developed for successful use of vegetable oil is the ELSBETT engine. Get more information about the vegetable oil engine and its application.
Some of ELSBETT`s latest developments are mulitfuel-conversion-kits for passenger cars and even for heavy-duty trucks. But we are not only concentrating on the multifuel possibility of engines. The improvement of engine performance is one of our main concerns. Our long time experience is reflected in a lot of patents and e. g. in the success of our test fleet.
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The ELSBETT piston comprises two interconnected parts:
- the piston head, made from nodular cast iron, and
- the piston body, made from aluminium, which are connected between themselves and to the piston rod by the piston pin.
The piston head houses the rings, and its functions are to seal and compress, and toreceive the vertical forces caused by the expansion of the gases. The piston head is made from nodular cast iron, which undergoes minimal thermal expansion and has low heat-conductive properties. Its thermal expansion is identical to that of the material used to construct the block and, therefore, it affords an excellent seal. The surface of the combustion chamber wall is of a reduced size so as to minimise the heat flow and, consequently, prevent the unnecessary overheating of the material.
The piston body provides lateralsupport (normal forces), and aids the cooling of the internal walls of the cylinder through thedistribution of lubricating oil. For this reason it is equipped with guide vanes and is made from aluminium. The static and thermal optimisation of the ELSBETT articulated piston enables it to be lighter than its aluminium counterpart.
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.
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.
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The fuel in the ELSBETT engine is injected locally and tangentially inside the central combustion area within the chamber. This process prevents the fuel and its residue from making contact with the walls, thus minimising the loss of heat. For this reason the injection nozzles have one aperture with a self-cleaning needle, and are arranged in a specific position and at a specific angle.
The built-in injection control system, which is a feature of ELSBETT engines, adjusts perfectly to the specific characteristics of each engine, and renders an additional injection pump unnecessary, thus reducing the number of parts and the weight of the engine. Larger engines are fitted with a dual injection system to minimise emissions. Each cylinder is fitted with two injection nozzles which are tangentially symmetrical.
Soot forms when the temperature, caused by the combustion of fuel at the beginning of the injection process, causes the decomposition of the fuel injected at the end of the injectionprocess. The inclusion of a second injection nozzle in each cylinder makes it possible to reduce the injection time by almost 50%, and this substantially reduces the emission of soot and allows soot filters to be dispensed with.
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The aim of the system is to safeguard against the loss of useful energy in the form of heat outside the combustion chamber. For this reason the heat is concentrated inside the chamber so that it cannot reach the surfaces and become lost in a radiator.
The ELSBETT duothermic combustion system is based on the principle that the air circulates inside the combustion chamber and arranges itself into different layers according to differences in heat and density, thus forming a central hot air combustion area and an external surrounding layer of cooler excess air. The combustion chamber must be spherical and located in the piston itself. The shape and size of the inlet ducts are such that the inlet air moves in a circular motion. The fuel is injected tangentially and directed towards the inside of the combustion area, thus causing it to blend perfectly with the air. It does not reach the wall of the combustion chamber and, therefore, the formation of unwanted deposits is avoided.
The external layer of cooler, excess air acts as a thermal and acoustic insulator and prevents the fuel from making contact with the chamber walls. The reduced size of the surface of the combustion chamber wall minimises heat flow and the loss of energy.The noise level is kept low as a result of the internal pressure increase differential remaining constant during the combustion and equal to the pressure differential during the compression of the gases.