DE102018128101A1 - Supply system for supplying a CNG or LNG fuel - Google Patents

Abstract

Feed system (1) for feeding a gaseous fuel (2) from a pressure vessel (3) to a drive unit (4) converting the fuel (2) into a drive power, the feed system (1) being a line (2) conducting the fuel (2) 5), which is connected via a single-flow first end (6) to the pressure vessel (3) and via a single-flow second end (7) to the drive unit (4), the line (5) between the first end (6) and the second end (7) has a first parallel arrangement (8), in which the line (5) is subdivided into at least two partial sections (9, 10) connected in parallel, with at least one first pressure reducing device (11 ) and in the second section (10) at least one second pressure reducing device (12) is arranged.

Description

The invention relates to a supply system for supplying a gaseous (for example CNG or LNG fuel; hydrogen, etc.) fuel, which is stored in a pressure container in a gaseous or, in particular, in an at least partially liquefied state, from the pressure container to a drive unit converting the fuel into drive power, e.g. B. an internal combustion engine or a fuel cell. The feed system can be used in particular in mobile systems, e.g. B. be used in a motor vehicle.

For gas vehicles that are operated with CNG ("compressed natural gas") or with LNG ("Iiquefied natural gas"), e.g. B. a cold descent, especially under high load, critical, because after just a few meters a gas pressure regulator or other components, such as. B. injectors, can freeze and thus the motor vehicle may be unsuitable for driving.

It is already known to integrate the gas pressure regulator into the water circuit of the motor vehicle. However, this solution has proven to be too sluggish. H. the supply of heat cannot take place quickly enough, especially during a cold descent, so that icing can continue to occur.

Alternatively, a parking heater can be used to heat the gas pressure regulator, but due to the thermal inertia of the system, it must be started sufficiently early before the cold start of the internal combustion engine. Auxiliary heaters therefore require predictive planning and regularly consume a lot of fuel.

Furthermore, bivalent fuel systems can be kept in which the cold start and the cold run on another fuel suitable for a cold run, such as e.g. Petrol or diesel fuel, and only then is it switched to CNG or LNG fuel.

From the DE 10 2006 045 031 A1 is known to add a freezing point lowering component to the natural gas.

From the DE 10 2007 036 958 A1 is known to carry out an injection of natural gas via several injection points. This should make it possible to use simpler components, which can then be used to precisely allocate fuel to individual cylinders.

In the DE 10 2010 020 795 A1 a latent heat storage is proposed as a heat source for a pressure reducer.

In the DE 10 2012 208 637 A1 It is proposed to use a piezoelectric injector to introduce gaseous fuels into a fuel cell.

From the DE 10 2014 206 369 A1 a pressure regulator is known through which gaseous fuel can be supplied to an engine under a variable pressure.

From the DE 10 2016 105 048 A1 It is known to provide a heating device for each of the tank control valve, pressure control device and gas injection valve, so that cooling of the valves caused by the Joule-Thomson effect can be compensated for. An outlet pressure of the stored natural gas fuel is gradually reduced by each of the devices mentioned.

From the DE 10 2016 209 025 A1 a cryogenic pressure vessel system is known, in which a gaseous fuel is successively expanded via several pressure regulators. The expansion cold that arises in each case is compensated for by heat exchangers arranged separately from one another, a liquid heat exchanger and a gas heat exchanger.

From the DE 10 2016 220 345 A1 a single-stage or multi-stage expansion of a gaseous fuel is known. The pressure reducer is a leak-free fluid power machine, so that the mechanical expansion performance can be used for the operation of the motor vehicle.

From the WO 2017/140480 A1 it is known that the gas injection valve provided for injecting a gaseous fuel can be temporarily bypassed at least during cold operation of a motor vehicle. During this time, the fuel is fed directly into the fresh gas line via another supply line.

The object of the present invention is to at least partially solve the problems mentioned with reference to the prior art. In particular, a particularly advantageous heating is to be proposed in a supply system for supplying a gaseous (for example CNG or LNG fuel; hydrogen, etc.) fuel.

A feed system with the features according to claim 1 contributes to solving these problems. Advantageous further developments are the subject of the dependent claims. The features listed individually in the patent claims can be combined with one another in a technologically expedient manner and can be explained by explanatory facts from the description and / or details from the figure are supplemented, further embodiment variants of the invention being shown.

A supply system for supplying a gaseous (for example CNG or LNG fuel; hydrogen, etc.) fuel from a pressure container to a drive unit converting the fuel into a drive power is proposed. The supply system comprises a line carrying the fuel, which can be connected or is connected to the pressure vessel via a single-flow first end and to the drive unit via a single-flow second end, the line having a first parallel arrangement between the first end and the second end the line is subdivided into at least two sections connected in parallel, at least one first pressure reducing device being arranged in the first section and at least one second pressure reducing device being arranged in the second section.

The fuel is stored in the pressure tank at a pressure between at least 10 bar and in particular up to 1,500 bar. The fuel can be taken from the pressure vessel directly or via a valve or a pressure reducer and transferred to the supply system via the first end of the line.

The feed system can be connected or connected to the drive unit via a second end. In particular, further components can be arranged between the second end and the drive unit (injection valves, a so-called common rail, further pressure reduction devices, etc.).

The delivery system includes a first end, a second end, and at least a first parallel arrangement therebetween. The first end and the second end or the line section forming the first end and the second end are each designed with a single flow, i. H. the (entire) fuel is led through a single channel or lumen in the single-flow line section. The parallel arrangement comprises at least two (possibly also more than two) sections of the line connected in parallel. I.e. a volume flow entering the supply system via the first end can be directed through the first section, through the second section (through further sections) or divided by both (several or even all) sections to the second end at the same time.

At least one pressure reducing device or a plurality of pressure reducing devices (orifices, valves, controllable valves, etc.) are arranged in the first section and the second section (and in particular also in each further section).

A volume flow of the fuel can be divided at least temporarily with the subsections, so that a pressure reduction or expansion of the fuel can take place in several line sections connected in parallel to one another.

By dividing the expansion into at least two pressure levels, the heat of expansion per pressure level is reduced in particular. As a result, less cooling is found at the individual pressure stage, so that freezing of the pressure reducing device is avoided or delayed. At the same time, more heat can be introduced into the volume flow of the fuel via the enlarged heat transfer surfaces.

In particular, a plurality of pressure reduction units can be arranged in at least one of the subsections, preferably in both or all subsections. By arranging several (similar or different) pressure reduction units, the pressure of the fuel can be lowered in particular successively. The (now smaller) expansion heat that occurs for each pressure level leads to less cooling at the individual pressure level.

With each additional pressure level, more heat can be transferred per particle number flowing through compared to a single-level pressure reducing device, so that the temperature level of the volume flow is increased more in comparison. The clever division of the pressure levels can also simplify the construction of the individual components (especially the use of orifices). These can also be manufactured more cheaply.

In particular, the individual pressure reduction units, that is to say the series and / or parallel pressure reduction units, can be arranged at least partially spatially spaced from one another.

Due to the spatial separation, individual pressure levels can be placed so that they are technically easier due to heat sources e.g. B. can be supplied with heat in the motor vehicle.

In particular, at least one further pressure-reducing device is arranged in the line between the first end and the second end and at least upstream or downstream of the sections.

The further pressure reducing device is arranged in particular in the single-flow line section.

In particular, at least one second parallel arrangement is arranged in the line between the first end and the second end and at least upstream or downstream of the sections. The second parallel arrangement can be constructed in the same way or differently.

In particular, between the several parallel arrangements, a single-flow (but possibly also a multi-flow) line section corresponding to the number of sections, for example, is provided.

In particular, at least one pressure reduction unit has a controllable pressure reducer (e.g. a gas pressure regulator or a valve). In particular, a volume flow and / or a pressure drop can be regulated via the adjustable pressure reducer. In particular, each pressure reduction unit can be regulated individually. The regulation can preferably take place in stages (opened / closed and / or at least partially opened) or continuously.

In particular, at least one pressure reduction unit has an (uncontrollable) orifice. In particular, the orifice comprises a flow cross-section that is reduced compared to the lines running upstream of the orifice, so that a predeterminable pressure drop can be generated across the orifice.

In particular, the at least one pressure reduction unit has an adjustable pressure reducer and an (non-adjustable) orifice, and is therefore of two stages.

In particular, at least one pressure reduction unit has a heating device for heating the pressure reduction unit.

In particular, a pressure reduction unit can be controlled at least via a temperature sensor. In particular, it can thus be ascertained whether the pressure reduction unit reaches a critical temperature above which the pressure reduction unit can be expected to freeze. A flow of the fuel through the pressure reduction unit can then be regulated accordingly, so that further cooling does not take place. In particular, depending on the temperature, a heating device can also be operated and / or regulated.

A heater can e.g. B. have a heat exchanger z. B. uses a liquid or gaseous heat exchange medium for heat transport to the fuel. In particular, the heating device can comprise an electric heating device or a burner.

In particular, at least two pressure reduction units have heating devices which are designed separately from one another.

Preferably, at least two pressure reduction units of a parallel arrangement have heating devices which are designed separately from one another.

In particular, each pressure reduction unit can be heated via its own heating device.

The separate arrangement of heating devices enables the heat required for the expansion of the fuel and the avoidance of freezing to be drawn from several environments, so that more heat can be provided.

In the case of heating, if possible directly after a first pressure reduction unit downstream of the pressure vessel, the temperature difference which is still particularly great there can be used to heat the volume flow (with the associated better heat transport).

The line sections present between the individual pressure reduction units or pressure stages enable heat to be introduced over the greatest possible length of the line to the at least partially expanded and already cooled fuel.

A motor vehicle is also proposed, at least comprising a pressure tank for a fuel, a drive unit converting the fuel into drive power (e.g. an internal combustion engine or a fuel cell) and the described supply system connecting the pressure tank to the drive unit.

The statements regarding the feed system apply equally to the motor vehicle and vice versa.

As a precaution, it should be noted that the numerals used here ("first", "second", ...) serve primarily (only) to differentiate between several similar objects, sizes or processes, in particular, no dependency and / or sequence of these objects, sizes or dictate processes to each other. If a dependency and / or sequence is necessary, this is explicitly stated here or it obviously results for the person skilled in the art when studying the specifically described configuration.

• 1: Kraftfahrzeug mit einer Antriebseinheit und mehreren unterschiedlichen Ausführungsvarianten eines Zuführsystems.

The invention and the technical environment are explained in more detail below with reference to the accompanying figure. It should be noted that the invention is not intended to be limited by the exemplary embodiments mentioned. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figure and to combine them with other components and findings from the present description. In particular, it should be pointed out that the figure and in particular the proportions shown are only schematic. Show it:

• 1 : Motor vehicle with a drive unit and several different design variants of a feed system.

1 shows a motor vehicle 18th with a drive unit 4th , an exhaust gas aftertreatment unit and several different design variants of a supply system 1 (Variant a) - not according to the invention and variants b), c) and d).

Variant a) (not according to the invention) shows a feed system 1 with a single-flow line 5 that have a single-ended first end 6 with the pressure vessel 3rd and a single-flow second end 7 with the drive unit 4th connected is. The feed system 1 comprises a first pressure reducing device 11 and a third pressure reducing device 13 that are in succession in the same line 5 are arranged. Both pressure reducing devices 11 , 13 are adjustable pressure reducers 15 , which can be controlled or regulated as a function of a pressure or a temperature in the line.

Variant b) shows a feed system 1 with a single-flow line 5 that have a single-ended first end 6 with the pressure vessel 3rd and a single-flow second end 7 with the drive unit 4th connected is. The administration 5 points between the first end 6 and the second end 7 a first parallel arrangement 8th on at which the line 5 in two parallel sections 9 , 10th is divided, being in the first section 9 a first pressure reducing device 11 and in the second section 10th a second pressure reducing device 12th is arranged.

The pressure reducing devices 11 , 12th are each designed to be adjustable and spaced from each other, so that for the expansion of the fuel 2nd and the avoidance of freezing required heat can be drawn from multiple environments.

Variant c) includes a parallel arrangement 8th with first and second pressure reducing devices 11 , 12th . In every section 9 , 10th the parallel arrangement 8th is a further third pressure reducing device 13 arranged. The first and second pressure reducing devices 11 , 12th are each adjustable, the third pressure reducing devices 13 as a non-adjustable aperture 16 are executed.

Downstream of the parallel arrangement 8th and a fourth pressure-reducing device that can be regulated as a function of pressure is spaced from this 14 arranged.

Variant d) comprises two series-connected parallel arrangements 8th . Between the parallel arrangements 8th is the line 5 executed with one eye. Any parallel arrangement 8th is with first and second pressure reducing devices 11 , 12th executed. In every section 9 , 10th any parallel arrangement 8th is a further third pressure reducing device 13 arranged. The first and second pressure reducing devices 11 , 12th are each adjustable, the third pressure reducing devices 13 as a non-adjustable aperture 16 are executed. The first and second pressure reducing devices 11 , 12th are adjustable depending on a temperature in each section 9 , 10th via its own temperature sensor 19th is recorded.

Downstream of the parallel arrangements 8th is a pressure sensor 21st to determine the pressure in the line 5 arranged. Upstream of the parallel arrangements 8th is immediately adjacent to the pressure vessel 3rd an adjustable fourth pressure reducing device 14 arranged.

Reference symbol list

1

Feeding system

2nd

fuel

3rd

pressure vessel

4th

Drive unit

5

management

6

first end

7

second end

8th

Parallel arrangement

9

first section

10th

second section

11

first pressure reducing device

12

second pressure reducing device

13

third pressure reducing device

14

fourth pressure reducing device

15

Pressure reducer

16

cover

17th

Heater

18th

Motor vehicle

19th

Temperature sensor

20th

Exhaust aftertreatment device

21

Pressure sensor

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102006045031 A1 [0006]
• DE 102007036958 A1 [0007]
• DE 102010020795 A1 [0008]
• DE 102012208637 A1 [0009]
• DE 102014206369 A1 [0010]
• DE 102016105048 A1 [0011]
• DE 102016209025 A1 [0012]
• DE 102016220345 A1 [0013]
• WO 2017/140480 A1 [0014]

Claims (10)

Feed system (1) for feeding a gaseous fuel (2) from a pressure vessel (3) to a drive unit (4) converting the fuel (2) into a drive power, the feed system (1) having a line (2) guiding the fuel (2) 5), which can be connected via a single-flow first end (6) to the pressure vessel (3) and via a single-flow second end (7) to the drive unit (4), the line (5) between the first end (6) and the second end (7) has a first parallel arrangement (8), in which the line (5) is divided into at least two partial sections (9, 10) connected in parallel, with at least one first pressure reducing device (11 ) and in the second section (10) at least one second pressure reducing device (12) is arranged. Feed system (1) after Claim 1 , At least one further pressure reducing device (13, 14) being arranged between the first end (6) and the second end (7) and at least upstream or downstream of the sections (9, 10) in the line (5). Feed system (1) according to one of the preceding claims, wherein between the first end (6) and the second end (7) and at least upstream or downstream of the sections (9, 10) in the line (5) at least one second parallel arrangement (8) is arranged. Feed system (1) according to one of the preceding claims, wherein at least one pressure reduction unit (11, 12, 13, 14) has a controllable pressure reducer (15). Feed system (1) according to one of the preceding claims, wherein at least one pressure reduction unit (11, 12, 13, 14) has an orifice (16). Feed system (1) according to one of the preceding claims, wherein at least one pressure reduction unit (11, 12, 13, 14) has an adjustable pressure reducer (15) and an orifice (16). Feed system (1) according to one of the preceding claims, wherein at least one pressure reducing unit (11, 12, 13, 14) has a heating device (17) for heating the pressure reducing unit (11, 12, 13, 14). Feed system (1) according to one of the preceding claims, wherein at least two pressure reduction units (11, 12, 13, 14) have heating devices (17) which are designed separately from one another. Feed system (1) after Claim 8 wherein at least two pressure reduction units (11, 12, 13, 14) of a parallel arrangement (8) have heating devices (17) which are separate from one another. Motor vehicle (18), at least comprising a pressure tank (3) for a fuel (2), a drive unit (4) converting the fuel (2) into a drive power, and a supply system (1) connecting the pressure tank (3) to the drive unit (4) ) according to one of the preceding claims.

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