WO2009118207A1

WO2009118207A1 - Power-generating machine and method for extending the storage life of fuel

Info

Publication number: WO2009118207A1
Application number: PCT/EP2009/050872
Authority: WO
Inventors: Peter Bothner; Martin Klander; Timo Steinbach; Helmar Gruhl; Stefan Genze; Alexander Von Stockhausen; Tobias Bender; Andreas Rebmann; Dieter Eppinger; Martin Mangold
Original assignee: Robert Bosch Gmbh
Priority date: 2008-03-25
Filing date: 2009-01-27
Publication date: 2009-10-01
Also published as: DE102008000805A1

Abstract

The invention relates to a power-generating machine (1), preferably a reciprocating power-generating machine, especially a motor vehicle or a machine, comprising a fuel tank (5) for fuel, especially biodiesel, and/or for fuel having a biodiesel percentage, for operating a combustion engine (2), especially a piston engine. The power-generating machine is characterized by means (6) for minimizing the oxygen content and/or the oxygen percentage in the fuel tank (5). The invention further relates to a method for extending the storage life of fuels in a power-generating machine (1).

Description

description

title

Engine and method for extending the service life of fuel

State of the art

The invention relates to an engine, preferably a ne piston engine, in particular a motor vehicle or a work machine, according to the preamble of claim 1, and a method according to the preamble of claim 8. Furthermore, the invention relates to a use of means for reducing the amount of oxygen and / or the oxygen content in a fuel tank according to claim 11.

From DE 101 52 084 Al it is known to operate internal combustion engines of motor vehicles with biodiesel. Biodiesel is a, after its use, the diesel fuel corresponding, at least partially vegetable and / or animal, fuel. In contrast to conventional diesel fuel, it is not derived from crude oil, but from vegetable oil or animal fats. From a chemical point of view, biodiesel is fatty acid methyl ester (FAME). The admixture of biodiesel to conventional diesel fuel is referred to as B5, BIO or B20, depending on the proportion. This corresponds to 5, 10 or 20% of biodiesel. B100 therefore corresponds to pure biodiesel.

A major disadvantage of biodiesel is that it ages comparatively quickly. An aged fuel, however, leads after a short time, depending on the ro- the system's durability, different service life for the safe failure of the injection system of the internal combustion engine. Increasing the proportion of biodiesel in the fuel reduces the time duration, ie the residence time in the tank, up to which the fuel is defined as unaged. This period of time is referred to as induction period (IP) in the laboratory test (EN 14112).

One of the main drivers of the aging of fuel, especially biodiesel or biodiesel fuels, is oxygen.

From EP 1 537 323 Bl a rigid fuel tank is known. In such fuel tanks, the oxygen consumed during the aging of the fuel is tracked by diffusion through the tank ventilation from the environment into the tank atmosphere. Furthermore, the gas volume in the fuel tank is compensated with decreasing tank level with fresh air from the atmosphere. In addition, expansion and contraction of the fuel in the fuel tank due to temperature variation (day-night, solar radiation, change of location, etc.) can be observed. This fuel volume change also results in gas exchange between the tank atmosphere and the environment, which introduces "fresh" oxygen into the tank from the outside, which in turn accelerates the aging of the fuel.

DISCLOSURE OF THE INVENTION Technical Problem

The invention is therefore based on the object to propose an engine, in the fuel, in particular biodiesel or a biodiesel containing fuel over the longest possible period for operating the internal combustion engine is available. Furthermore, the object is to propose a method for increasing the service life of fuel in an engine.

Technical solution

This object is achieved with regard to the engine, preferably the piston engine, in particular the motor vehicle or the working machine, with the features of claim 1 and by a use according to claim 11. With regard to the method, the object is achieved with the features of claim 8. Advantageous developments of the invention are specified in the subclaims. All combinations of at least two features disclosed in the description, the claims and / or the figures also fall within the scope of the invention. In order to avoid repetition, features disclosed in accordance with the device should also be regarded as disclosed according to the method and be able to be claimed. Likewise, according to the method disclosed features should be considered as device disclosed and claimed claimable.

The invention is based on the idea of slowing down the aging of fuel, in particular of biodiesel or of fuel, preferably diesel, with a biodiesel fraction, in that the amount of oxygen and / or the oxygen content, ie the oxygen concentration, in the fuel tank, in particular in the tank atmosphere (Gas atmosphere) is minimized above the fuel. By providing means for minimizing the amount of oxygen and / or the oxygen content (volume and / or weight fraction) in the fuel tank, the aging process of the Fuel can be slowed down because the fuel in an engine designed according to the concept of the invention, preferably in a piston engine, especially in a motor vehicle or a working machine, in the fuel tank no longer in contact with oxygen or only a very small amount of oxygen / concentration , Preferably, the means for minimizing the amount of oxygen and / or the oxygen content, are designed such that they prevent the supply of fresh air containing oxygen from outside and thereby interrupt the supply of oxygen necessary for the aging of the fuel.

In the following, advantageous embodiments are described using the example of a motor vehicle, wherein the invention is not limited to such an engine.

Particularly advantageous is the use of means for minimizing the amount of oxygen and / or the oxygen content in the fuel tank in motor vehicles with a designed as a diesel engine combustion engine for burning biodiesel or a fuel, preferably diesel, with a Biodieselanteil. Especially biodiesel and biodiesel-containing fuels are particularly susceptible to an oxygen input. Biodiesel is not understood to mean a natural or merely filtered vegetable oil which can also be used as biofuel in special internal combustion engines. This also applies to bioethanol fuel, which is also not biodiesel. Preferably, biodiesel is understood as a fuel or a fuel fraction, as defined in E DIN 51606 and / or DIN EN 14214. In a further development of the invention is advantageously provided that the means for minimizing the amount of oxygen and / or the oxygen content in the fuel tank are designed such that they minimize the gas volume above the fuel in the fuel tank, so the atmosphere volume in the fuel tank, preferably at least approximately zero ,

One way to minimize the volume of the atmosphere or gas above the fuel in the fuel tank is to provide a flexible fuel tank volume that adapts to the actual volume of fuel in the tank. For this purpose, different principles can be used. For example, the fuel tank may have a flexible (stretchable) envelope in the manner of a balloon. Alternatively, the shell may not be stretchable, be formed in the manner of a plastic bag. Additionally or alternatively, the fuel tank may be configured in the manner of a concertina. Thus, it is both an embodiment feasible, in which the fuel tank volume automatically, for example, by the use of a spring or by at least partially flexible design of the fuel tank adapts to the fuel volume. Additionally or alternatively, at least one drive motor, in particular an electric motor for changing the fuel tank volume depending on the fuel volume can be used. Preferably, a fuel tank designed to be variable in volume is configured such that at least approximately the entire tank internal volume is filled with fuel. As a result, it is not necessary to track air from outside into the fuel tank. Additionally or preferably, as an alternative to providing a variable volume fuel tank, it is possible to minimize the oxygen content by supplying inert gas into the fuel tank. Preferably, the oxygen present in the fuel tank atmosphere is displaced from the inert gas to the outside, whereby not only the oxygen content, but also the amount of oxygen is minimized overall. Nitrogen is preferably used as the inert gas. By inerting the fuel tank, a contact of the fuel in the fuel tank with oxygen, at least largely prevented.

An embodiment is preferred in which an inert gas generator is provided in the motor vehicle for supplying the fuel tank with inert gas. Alternatively, it is possible to provide an inert gas storage, that is to say an inert gas storage container, in particular a pressure container (compressed gas cylinder), which can be topped up regularly, in particular during service workshop stays. It is also conceivable to couple an inert gas storage with an inert gas generator, such that the inert gas storage serves as an intermediate storage for the inert gas produced by the inert gas generator.

In order to prevent a temperature-induced "breathing" of the fuel tank and a diffusion of oxygen in the fuel tank, is provided in a further development of the invention advantageously that the fuel tank is designed as a pressure-resistant tank with a pressure relief valve. Preferably, the pressure relief valve opens only at a defined overpressure within the fuel tank, in particular of about 0.5 bar. The overpressure is caused for example by solar radiation and / or the ambient temperature. The purpose of the pressure relief valve is that compressed gas is not released immediately to the atmosphere as in the prior art, but only when a limit pressure is exceeded. As a result, less air must be drawn in from the outside as the pressure in the fuel tank falls. The at least one pressure relief valve is preferably coupled to a controlled or regulated tank ventilation device, wherein the tank ventilation device (for example, a vacuum valve) is preferably designed under vacuum control or regulated. In other words, an afterflow of air or preferably of inert gas is made possible only in the event that the pressure within the fuel tank, in particular caused by a fuel consumption, falls below a predetermined pressure value. Preferably, this pressure value is located in the vacuum range between about 0.1 to 0.5 bar vacuum.

The invention also leads to a method to be used in an engine, preferably in a piston engine, in particular in a motor vehicle or in a work machine, for extending the service life of fuel for operating an internal combustion engine. Preferably, the method extends the useful life of biodiesel or of fuel, in particular diesel with a biodiesel share. According to the invention, the extension of the service life of the fuel is achieved by reducing or minimizing the amount of oxygen and / or the oxygen content in the fuel tank, in particular in the fuel tank atmosphere.

As mentioned, it is particularly preferred to reduce the amount of oxygen and / or the oxygen content in fuel tanks containing biodiesel or a biodiesel. the fuel is stored, and / or which are suitable or formed for receiving biodiesel or fuel with a Biodieselanteil.

The amount of oxygen and / or the oxygen content in the fuel tank can be minimized or reduced in many ways, preferably reduced to zero. For example, it is possible to minimize the total gas volume, that is to say the entire fuel tank atmosphere above the fuel tank, in particular through the use of a variable-volume fuel tank. Additionally or alternatively, the amount of oxygen may be minimized by supplying inert gas, preferably by simultaneously displacing oxygen into the fuel tank. Additionally borrowed or alternatively, it is possible to form the fuel tank as a pressure tank and assign this to a pressure relief valve, with a regulated fuel tank ventilation for supplying outside air and / or inert gas is provided depending on the capacity.

Furthermore, the invention leads to a use of means for reducing the amount of oxygen and / or the oxygen content in a fuel tank in an engine. These agents are preferably used in a piston engine, in particular in a motor vehicle or in a working machine, which are designed to operate with biodiesel or with a fuel with biodiesel component. Brief description of the drawings

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. These show in:

1 shows a first embodiment of an engine designed as a motor vehicle with a variable volume fuel tank.

2 shows a second embodiment of an engine in which the fuel tank is assigned an inert gas supply; and

Fig. 3 shows a third embodiment of an engine, wherein the fuel tank is equipped as a pressure tank with a pressure relief valve and a regulated fuel tank ventilation.

Embodiments of the invention

In the figures, the same components and components with the same function with the same reference numerals are marked.

In Fig. 1, an engine designed as a motor vehicle 1 with a designed as a diesel engine for combustion of fuels with Biodieselanteil combustion engine 2 is shown. The internal combustion engine 2, more precisely an injection system of the internal combustion engine 2, is hydraulically connected via a fuel line 3 to a fuel pump 4 with a fuel tank 5. The engine 1 is equipped with means 6 for reducing the amount of oxygen and / or the oxygen content in the fuel tank 5. In the exemplary embodiment shown, the means 6 comprise the fuel tank 5, which is designed to be variable in volume. For this purpose, the fuel tank 5 on an outer support contour 7, in which a bag-like container 8 is added. The bag-like container 8 consists in the embodiment shown of a fuel-resistant, non-stretchable film. If fuel, in particular biodiesel or fuel with biodiesel content, is withdrawn from the container 8, the volume of the container 8 decreases corresponding to the volume of fuel removed. On the one hand, this is due to the foldable or crumpled outer wall of the bag-like container 8 and, secondly, that the container 8 is closed in a gas-tight manner, ie at least approximately no gas cushion is inside the container 8, as a result of which the volume of the container 8 automatically arrives the removal of fuel decreases and expands as fuel is refueled.

According to an alternative variant, not shown, the entire fuel tank 5 or a container 8 arranged in a support contour 7, for example by motor or spring force, can be enlarged or reduced, so that the volume provided for the fuel adapts to the current fuel volume in the fuel tank 5 , According to yet another alternative embodiment, the wall of the fuel tank 5 is stretchable, in the manner of a balloon.

In Fig. 2 is an alternative embodiment of an engine designed as a motor 1 with a Combustion engine 2 shown, which is connected via a fuel line 3 with fuel pump 4 with a rigid fuel tank 5. In the fuel tank 5 opens an inert gas 9, which connects the fuel tank 5 with an inert gas storage container 10 (pressure bottle). By supplying inert gas into the fuel tank 5, air present in the fuel tank 5 can either escape via the filler neck 11 or a discharge line 12, the discharge line 12 preferably being connected to a suitable filter mechanism (not shown).

In the embodiment shown in FIG. 2, the inert gas storage container 10 is supplied by an inert gas generator 13 with newly produced or recovered inert gas. It is also an embodiment feasible, is dispensed with either the Inertgasvorratsbehältnis 10 or on the inert gas generator 13.

In the embodiment according to FIG. 3, an internal combustion engine 2, which is connected to a rigid fuel tank 5 via a fuel line 3 with a fuel pump 4, is again provided in the engine 1 designed as a motor vehicle. The fuel tank 5 is executed in the embodiment shown as a pressure vessel and equipped inside the tank nozzle 11 with a pressure relief valve 14 which opens at a defined pressure. The pressure relief valve 14 can also be arranged in a separate discharge line, not shown. In this case, the filler neck 11 is pressure-tight closable. If fuel is removed from the fuel tank 5 via the fuel line 3, the fuel tank 5 is vented via a regulated tank ventilation device 15 - in this embodiment, with ambient air. It is also conceivable to "aerate" the fuel tank 5 exclusively with inert gas. Preferably, only regulated volume of gas is supplied by the controlled ventilation, which was taken from fuel via the fuel line 3. Preferably, the tank ventilation device 15 is provided with a negative pressure control, which initiates ventilation of the fuel tank 5 only when falling below a predetermined limit pressure.

Claims

claims

1. Engine, preferably piston engine, in particular motor vehicle or work machine, with a fuel tank (5) for fuel, in particular for biodiesel and / or for fuel with a biodiesel component, for operating an internal combustion engine (2), in particular a piston engine,

characterized,

in that means (6) for minimizing the amount of oxygen and / or the oxygen content in the fuel tank (5) are provided.

2. Engine according to claim 1, characterized in that the internal combustion engine (2) is a diesel engine, in particular for burning of biodiesel and / or of a fuel with a biodiesel component.

3. Engine according to one of claims 1 or 2, characterized in that the means (6) are designed to minimize the gas volume above the fuel in the fuel tank (5).

4. Engine according to one of the preceding claims, characterized in that the fuel tank (5) is variable in volume.

5. Engine according to one of the preceding claims, characterized in that the means (6) minimize the amount of oxygen by supplying inert gas into the fuel tank (5).

6. Engine according to claim 5, characterized in that the means (6) comprises an inert gas generator (13) and / or an inert gas storage container (10).

7. Engine according to one of the preceding claims, characterized in that the means (6) comprise a fuel tank (5) sealing overpressure valve (14) and preferably one, in particular a control and / or control device having, tank ventilation device (15).

8. A method for extending the service life of fuel for operating an internal combustion engine (2) of an engine (1), preferably a piston engine, in particular a motor vehicle or a work machine,

characterized,

that the amount of oxygen and / or the oxygen content in the fuel tank (5) is reduced.

9. The method according to claim 8, characterized in that as a fuel biodiesel or a biodiesel containing fuel is used.

10. The method according to any one of claims 8 or 9, characterized in that the amount of oxygen and / or the oxygen content by minimizing the gas volume above the fuel and / or by supplying inert gas into the fuel tank (5) and / or by the provision of a pressure relief valve (14) is reduced in combination with a tank ventilation device (15).

11. Use of means (6) for reducing the amount of oxygen and / or the oxygen content in a, preferably for operating with biodiesel or formed with a fuel containing a biodiesel fuel tank (5) in an engine (1), preferably in one Piston engine, in particular in a motor vehicle or in a work machine.