DE102007044165A1 - Device for operating power plants with vegetable oil has at least one heating device in tank which holds vegetable oil and is connected in non-positive or positive locking manner to open-pore metal foam structure - Google Patents

Abstract

The device for operating power plants with vegetable oil (8) has at least one heating device in the tank (1) which holds the vegetable oil and is connected in a non-positive or positive locking manner to an open-pore metal foam structure (6). A tube spiral (2) is integrated in the tank as the heating device and serves for the throughflow of warm engine oil or warmed cooling water. An electric heater may additionally be integrated in the vegetable oil tank.

Description

The The invention relates to a device for operating an engine system, preferably a diesel engine, with vegetable oil. Especially is about a device for reducing the viscosity of vegetable oil by preheating.

It has long been known that vegetable oil as a fuel can be used for engines. Already had Otto Diesel his first diesel engine successfully operated with rapeseed oil. Vegetable oil-powered engines could then, however do not enforce, because the production of diesel fuel to this Time was much cheaper than the production of vegetable oil.

today wins the use of vegetable oil in the course of increasing Oil shortage and due to the growing environmental awareness always more important. Vegetable oil is unlike diesel a renewable resource. In addition, the operation becomes of an internal combustion engine with vegetable oil compared to Operation with diesel emitted significantly less carbon dioxide and there are virtually no soot particles.

Of the However, the operation of diesel engines with vegetable oil raises technical Problems on. Because of its compared to diesel oil Vegetable oil can not be higher in viscosity be readily used to start a cold diesel engine. Also, the cold run of a powered by vegetable oil diesel engine is unsatisfactory because the engine runs very "out of round" and consequently subjected to higher wear is. In addition, the mix during the cold-running phase Plant with the engine oil, causing chemical reactions between the oils are allowed, the engine damage can cause.

Already Existing diesel engines must therefore be suitably retrofitted for operation with vegetable oil newly manufactured engines must be prepared accordingly be.

This Problem can be known by two different technical Approaches are solved. In the so-called two-tank solution the engine is started during startup and warm-up Diesel operated. The vegetable oil is both in the starting phase as well as in the further operation with the help of a heat exchanger, in which the warm engine oil or the heated cooling water circulated, heated. After the vegetable oil the Operating temperature has reached, the engine is on pure vegetable oil operation switched. Just before switching off the engine, this is still once rinsed with diesel fuel.

When Alternative diesel engines with mixtures of vegetable oil and diesel operated. In summer, a maximum of 80% and in winter 50% of the diesel fuel is replaced by vegetable oil.

at the so-called single-tank solution becomes the vegetable oil electrically heated before starting the engine, and this one immediately started with vegetable oil. To the lead times low Usually, just a small amount of it will keep Vegetable oil preheated. In the starting phase will the otherwise cold vegetable oil with the help of correspondingly strong Circulating pumps conveyed through the lines. After this the engine has warmed up, becomes the electric heater shut off and the vegetable oil before its supply to the engine analogous to the two-tank solution by the engine oil or the cooling water heated.

There Vegetable oil has a high viscosity is the heat distribution in the oil by convection low. It is therefore difficult to even the vegetable oil to heat or within the oil an equally distributed Adjust viscosity. For an economic Operation in particular of modern, electronically controlled, direct Injecting diesel engines, it is necessary to have a long service life the engines ensure this with vegetable oil of defined temperature / viscosity.

Out the prior art, numerous proposals are known which the supply of the engine with vegetable oil of defined Viscosity to the goal.

So will in DE 10 2005 053 095 B3 a fuel supply device for a diesel engine and a method for operating a fuel supply device for a diesel engine excited, which in addition to other components each having a first tank for the diesel oil and a second tank for vegetable oil or vegetable fat. The device has at least one heating device for heating the vegetable oil or fat conveyed from the second tank, and also a further heating device for heating the vegetable oil or fat directly in front of the injection pump.

In DE 44 33 500 C2 describes a two-tank system in which the engine is started with a liquid fuel (diesel) and the engine heat of the alternative fuel (vegetable oil) is preheated. In addition to alternative fuel, the fuel rail system and the fuel valves are preheated.

In both documents, attempts are made to compensate for the slow and uneven heating of the vegetable oil in a preheating vessel, that additional means for heating the oil between the preheating vessel and the injection nozzles of the engine are used. Although the problem is alleviated, the proposed solutions are technically complex and also consume comparatively much energy.

In DE 10 2004 014 119 B3 discloses a device for preheating vegetable oil for use in diesel engines, which consists of a tubular heat exchanger in which a fuel line with connecting channels for the cooling water is arranged so that the cooling water flows through the fuel line in the axial and radial directions and flows through.

hereby a comparatively good heat exchange is achieved. As the flow rate of the oil depends from the engine power, the temperature level of the oil also varies.

DE 100 60 573 B4 shows a vegetable oil engine system with a diesel tank and a vegetable oil tank, wherein between the vegetable oil tank and the engine, a thermal cylinder is arranged, which has a considerably smaller capacity than the vegetable oil tank. The thermal cylinder is provided with an electric heater which is controlled by a computer and heats the vegetable oil in the thermal cylinder to a predetermined temperature. A pump conveys the vegetable oil from the vegetable oil tank into the thermal cylinder, from which the engine sucks the vegetable oil when it has reached the predetermined temperature in the region of a solenoid valve in front of the engine.

By the exact regulation of the vegetable oil temperature becomes the Engine supplied with oil of defined viscosity, However, the solution is technically relatively complex and has a high energy consumption.

task The invention is an apparatus for operating engine announcements to create with vegetable oil that is simple and the engine vegetable oil of defined viscosity supplies.

These The object is achieved by the characterizing Characteristics of claim 1 solved. Advantageous versions The invention will become apparent from the claims 2 to 8.

The Device for operating engine systems with vegetable oil consists of a thermally insulated pot-shaped container with inlet and outlet pipes for the oil. For heating of vegetable oil is in the container at least a heater. According to the invention, the at least one heating device with an open-pored metal foam structure positively or materially connected. The metal foam serves as a heat exchanger.

For the use in a secondary fueling system is in the container only a heater introduced in the form of a pipe spiral. Through this warm flows during engine operation Engine oil or cooling water at a temperature of about 85 ° C. The device thus serves in two-tank systems for the vegetable oil at the same time as a buffer storage, thereby avoiding overheating of the vegetable oil is, and as a water heater.

For the use in a single-tank system, the container is additional to the pipe spiral still equipped with an electric heater. In addition, in the container is provided with a breakthrough Dividing wall placed, which the container in a lower and an upper compartment shares. The partition runs parallel to the bottom of the container. The pipe spiral is in the upper Compartment that is many times larger as the lower, arranged. In the lower compartment, that too the fuel supply line is connected to the engine is located the electric heater.

In front Starting the engine should be done by means of the electric heater the vegetable oil in the lower compartment to operating temperature to be heated. The lower compartment holds so much Vegetable oil that heats the crowd quickly on the one hand on the other hand, however, for warming up the Motors is sufficient.

Around the chemical decomposition of the vegetable oil and the breaking away to prevent fires, it is envisaged that the electric heater via a temperature control features. Nevertheless, local overheating can and an associated outgassing of the vegetable oil, the already at temperatures higher than 90 ° C not completely prevented. The one in the partition breakthrough allows the escape of the formed Gases. He also serves after the warm-up phase for the supply of the engine necessary transport of vegetable oil from the upper to the lower compartment.

typically, exists the used as a heat exchanger open-pore metal foam structure Aluminum and has a pore size of 2-5 mm. Of the Heat exchanger is preferably composed of two segments. The one segment is internally connected to the pipe spiral non-positively or positively and formed either tubular or cylindrical; the other segment is tubular, enclosing the Pipe spiral and is from the outside positive or positive connected to this.

To the supply of heat over the Me To further improve tallschaum, the tubular parts may have a graduated, from inside to outside or from outside to inside steadily increasing pore size. If a cylindrical part is used in the interior of the helical spiral, the pore size advantageously decreases steadily from the inside to the outside.

by virtue of The structure of the metal foam turns the vegetable oil into many small cells are split, evenly with heat be charged. Thus, the heating of the entire Vegetable oil in the container - in contrast to the prior art - almost at the same time, whereby the Engine with vegetable oil of constant temperature and Viscosity is supplied, which otherwise high Mass flow rates possible. Furthermore become local overheating and consequent outgassing avoided the vegetable oil.

The Invention can be used both in known two-tank systems and in Tank systems are used. In any case, due to the heat exchanger made of metal foam on additional circulation pumps and heaters in the supply lines to the engine respectively dispensed with the injectors.

at new diesel engines will not be the entire fuel supplied burned, but part of this fuel will be back in the Tank system returned. When passing through the engine the fuel is strongly heated. A return of the hot fuel into the preheat tank would lead to overheating of the fuel, since in operation after the warm-up phase, the heating of the Vegetable oil alone with the help of cooling water or Engine oil is sufficient. When using such engines, it is Therefore, provided that returned from the engine Vegetable oil, controlled by a valve while the warm-up phase in the Vorwärmbehälter and after the warm-up phase in the storage tank to lead.

The invention will be explained in more detail below with reference to two embodiments. To show the 1 to 5 schematic representations of a single and double tank system in different views including the corresponding block diagrams for operation.

In 1 the device for preheating vegetable oil for a two-tank system as well as its integration into the second tank system shown schematically there is shown. In such a system becomes the engine 12 first started with diesel fuel. During operation of the engine 12 circulates heated cooling water or

Engine oil through the feeder 2.1 and the process 2.2 through the pipe spiral 2 , This will make the vegetable oil 8th heated to about 60 to 80 ° C. Once this has reached the operating temperature, the supply of diesel fuel is interrupted and the engine 12 exclusively with vegetable oil 8th operated.

Out 2 is the truncated side view of the preheater for Zweitanksysteme seen. The pot-like vessel 1 is to reduce heat loss to the outside with foam or vacuum insulation 5 surround. About the feeder 3.1 becomes the vessel 1 cold vegetable oil 8th fed and over the output 3.2 becomes the vessel 1 heated vegetable oil 8th taken. The baffles 7 serve to swirl the cold vegetable oil 8th as it enters the vessel 1 , This results in a faster mixing of cold and warm vegetable oil 8th causes.

3 shows in a plan view of the preferred arrangement of the metal foam structure 6 in the container 1 , that they are with the spiral 2 is firmly connected both outside and inside. The introduced metal foam, preferably made of aluminum with a pore size of 2-5 mm, consists of two separate segments 6.1 ; 6.2 , which are tubular shaped. The wall thickness of the metal foam pipes is 5-15 mm.

Out 4 a device according to the invention for a single-tank system can be taken. With fundamentally the same structure as with the second tank system, it has a temperature-controlled, electric heater 4 for preheating the vegetable oil 8th , The heating system 4 is plate-shaped and has a standard power of 12 V for motor vehicle power of 1000 W. For motor vehicles with a vehicle electrical system voltage of 24 V is accordingly a heater 4 used with the same power but higher operating voltage.

Above the heater 4 is the dividing wall 9 in the container 1 introduced, which runs parallel to the bottom of the container and the container 1 in a lower compartment with a volume of about 200 ml, in which the electric heater 4 is located, and an upper compartment with about 2 l capacity, in which the pipe spiral 2 is located, divides. Before starting the engine 12 becomes only the vegetable oil in the lower compartment 8th heated to about 60 ° C and then the heating 4 automatically shut off. The capacity of the lower compartment of 200 ml is chosen so large that the amount of oil contained therein to warm up the engine 12 sufficient, on the other hand, however, can be heated comparatively quickly. In the lower compartment there is no metal foam, as the relatively small volume with the plate-shaped heater 4 fast and even he can be heated.

The partition 9 is with a central breakthrough 10 provided by 20 mm diameter. About the breakthrough 10 can escape the resulting during electrical preheating Ausgasprodukte the vegetable oil. With 20 mm is the breakthrough 10 so large that the necessary after the warm-up phase for engine operation transport of vegetable oil 8th from the upper compartment to the lower compartment.

To overheat the vegetable oil 8th In the operation of engines that do not burn all the fuel supplied, but to release a portion of the fuel highly heated via a return again, to avoid, is a guide of the vegetable oil 8th corresponding 5 necessary.

During the warm-up phase is using the pump 15 Vegetable oil to the engine 12 pumped. The vegetable oil released via the return is passed through the valve 13 and the line 3.3 into the lower compartment of the vessel 1 returned. After completion of the warm-up phase, the valve switches 13 , whereby the returning vegetable oil 8th in the tank 11 arrives.

If after prolonged use the vegetable oil 8th in the container 1 still exceeds a maximum temperature of 90 ° C, is over the line 3.4 with the help of the pump 14 hot vegetable oil 8th from the container 1 pumped out and over the line 3.1 cooler vegetable oil 8th from the tank 11 fed.

1.

pot-like container

Second

pipe spiral

2.1.

feed Engine oil or cooling water

2.2.

output Engine oil or cooling water

3.1.

feed Vegetable oil from the tank

3.2.

output Vegetable oil to the engine

3.3.

feed Vegetable oil from the engine (return)

3.4.

output Vegetable oil to the tank

4th

electrical heater

5th

isolation

6th

open-pored Metal foam structure

6.1

inner Metal foam segment

6.2

outer Metal foam segment

7th

baffles

8th.

vegetable oil

9th

partition wall

10th

breakthrough

11th

tank

12th

engine

13th

2.2 way valve

14th

pump (from the tank to the tank)

15th

pump (from the tank to the engine)

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102005053095 B3 [0011]
• - DE 4433500 C2 [0012]
• - DE 102004014119 B3 [0014]
• - DE 10060573 B4 [0016]

Claims (8)

Device for operating engine systems with vegetable oil ( 8th ) comprising a thermally insulated cup-shaped container ( 1 ), in which the vegetable oil to be heated is located, wherein in the container ( 1 ) at least one heating device is introduced, and the container ( 1 ) To- ( 3.1 ) and drainage pipes ( 3.2 ) for the vegetable oil ( 8th ), characterized in that the at least one heating device having an open-pored metal foam structure ( 6 ) is positively or materially connected. Device according to claim 1, characterized in that in the container ( 1 ) as a heating device, a pipe spiral ( 2 ), which is the flow of warm engine oil or heated cooling water, is introduced. Apparatus according to claim 1 and 2, characterized in that in the container ( 1 ) as heaters the pipe spiral ( 2 ) and in addition an electric heater ( 4 ) are introduced. Device according to claim 3, characterized in that in the container ( 1 ) parallel to the container bottom one with a breakthrough ( 10 ) provided partition ( 9 ) is inserted, which the container ( 1 ) in a lower compartment, in which the electric heating ( 4 ), and an upper compartment in which the pipe spiral ( 2 ), wherein the upper compartment has a much larger volume than the lower compartment. Apparatus according to claim 1 to 4, characterized in that the metal foam structure ( 6 ) made of aluminum, wherein it has a pore size of 2-5 mm. Apparatus according to claim 1 to 5, characterized in that the metal foam structure ( 6 ) consists of two separate segments, one of the two segments ( 6.1 ) inside and the other segment ( 6.2 ) outside with the pipe spiral ( 2 ) is positively or positively connected, and the inner segment ( 6.1 ) tubular or cylindrical and the outer segment ( 6.2 ) is tubular. Apparatus according to claim 6, characterized in that the tubular metal foam segments ( 6.1 . 6.2 ) have a wall thickness of 5-15 mm. Device according to claims 6 and 7, characterized in that the segments ( 6.1 . 6.2 ) have a graduated pore structure such that the pore size increases steadily from the inside to the outside or from outside to inside.