DE102007004456A1 - Drive unit for e.g. passenger car, has drive to which compressed combustible natural gas is provided as fuel, and hydraulic or pneumatic drive provided with pressurized fluid, where common pressure tank is provided for gas and fluid - Google Patents

Abstract

The drive unit (1) has a drive (2) to which a compressed combustible natural gas is provided as a fuel. A hydraulic or pneumatic drive (5) is provided with a pressurized fluid e.g. oil, where a common pressure tank (3) is provided for the compressed gas and the pressurized fluid. A balloon-shaped membrane is provided in the pressure tank for separately holding the compressed natural gas and the pressurized fluid. A support arranged at an inner wall of the tank is assigned to the membrane, where the tank has two openings to respectively intake the compressed gas and the pressurized fluid.

Description

The The invention relates to a drive unit for a motor vehicle and in particular for a car Invention a car with such a drive unit.

Hybrid vehicles that means vehicles with two drives a separate source of energy for each drive. has the motor vehicle, for example, as a drive an internal combustion engine and an electric machine, both a fuel tank needs also a power source, eg. As a fuel cell provided become. This makes hybrid vehicles more complex in their Construction.

The JP 2002067712 describes a vehicle with an oil tank. A first part of the oil tank is used to receive fuel oil for the machine of the vehicle. A second part of the oil tank serves to receive the hydraulic fluid for a hydraulically operated equipment of the vehicle.

The DE 102 01 930 A1 describes a vehicle with an internal combustion engine and an electric machine. The internal combustion engine drives a first axis and the electric machine drives a second axis of the vehicle. The electric machine is operated with a fuel cell system.

It is an object of an embodiment of the invention, a to provide structurally simplified hybrid vehicle.

The Solution to this problem is the characteristics of the independent Claims. Advantageous developments and further embodiments result with the features of the dependent claims.

One The first aspect of the invention relates to a drive unit for a motor vehicle with two drives. A first drive exists in an internal combustion engine and is powered by a compressed combustible gas operated. The second drive is a hydraulic or a pneumatic one Drive, so it is associated with a pressurized fluid. For the two drives a common pressure vessel is provided So a pressure vessel for both the compressed Gas as well as for the pressurized fluid. The pressure vessel is usually designed, working pressures of up to 350 to allow bar.

Of the proposed hybrid drive initially has a first Drive, which is a compressed combustible gas, for example, compressed Natural gas, as an energy source. It is the first one Drive thus a CNG (compressed natural gas) drive, typically a long range of, for example Has 300 km or more.

Of the first drive is supplemented by a second drive. The second drive is a hydraulic or a pneumatic one Drive, compared to a lower fuel consumption a vehicle that has only one CNG drive. This is because the second drive is charged during braking is and thus braking energy for the drive of the vehicle can harness, resulting in optimized energy consumption to adjust.

With the second drive can still be a special create a sporty vehicle with excellent acceleration values. This is because the pressurized fluid and the second drive typically a high energy density and a high energy conversion rate (i.e. H. Energieaufladung or discharge). For hydraulic Propulsion, for example, is unlike electric battery-based Actuated the energy conversion rate practically only by the valve sizing and the motor dimensioning limited, but not of z. B. chemical Conversion processes in the battery dependent. Relative small hydraulic drive units already have a lot here high power densities, which are significantly larger as those of electric machines.

• a) zur Optimierung der Fahreigenschaften des betreffenden Fahrzeugs heranzuziehen, die zunächst vom ersten Antrieb bestimmt sind. Dadurch können temporär erhöhte Fahrzeugbeschleunigungswerte erzielt werden, die Fahrleistung oder der Zugkraft verbessert werden.
• b) zur Energieverbrauchsminimierung heranzuziehen, indem der erste Antrieb in bestimmten Fahrsituationen wie z. B. einem Beschleunigungsvorgang teilweise oder gänzlich abgestellt wird.

The choice of a second drive with such a high energy density and energy conversion rate allows it optionally

• a) to optimize the driving characteristics of the vehicle in question, which are initially determined by the first drive. As a result, temporarily increased vehicle acceleration values can be achieved, the driving performance or the tractive force can be improved.
• b) to minimize energy consumption by the first drive in certain driving situations such. B. an acceleration process is partially or completely turned off.

Of course These two possibilities can also be combined use.

in the Case of a hydraulic drive, the drive unit still has a surge tank so that the pressurized fluid from flow in a region of high pressure to a region of lower pressure can. In the pneumatic drive, the surrounding air serves as a reservoir, so no additional pressure equalization tank is required.

The second drive is essentially an auxiliary drive, that is, in the event that a vehicle is exclusively powered by it, the range of the vehicle is significantly smaller than that in exclusive use of the CNG drive. For example, in a mid-range vehicle, the CNG drive can provide a range of 300 km or more, whereas the hydraulic or pneumatic drive only provides a maximum range of 50 km. This is adjusted by the volume available to the pressure fluid, which may be less than 30 l for this purpose.

The prescribed drive unit sees only a single pressure vessel or memory before, because of the fulfillment of high safety Requirements to produce complex and expensive. In order to the proposed hybrid drive is safer, structurally simplified, in production easier and its manufacturing costs lowered.

Becomes the pressure vessel when refueling with a compressed Gas filled for the first drive, so is at this construction of the drive unit of the hydraulic or pneumatic storage, that is the part of the pressure vessel, the for the pressurized fluid is provided automatically with charged, d. H. is thus automatically under pressure. A separate recharge this memory is eliminated. A pump to provide the corresponding pressure of the pressurized fluid is thus not required, thereby the drive unit is further simplified and also cheaper.

at an embodiment is a membrane for the separate provision of compressed gas and pressurized fluid in the pressure vessel intended. The membrane ensures separation of compressed gas and pressurized fluid. For this she is for these two media impermeable trained. Because the two media have a comparable Pressure, the diaphragm does not have a significant pressure difference between compensate them, so no special requirements regarding their mechanical load capacity exist. Due to their elasticity it adapts to the respective capacity of the media in the pressure vessel at.

In In one embodiment, the membrane is one on the inner wall associated with the pressure vessel arranged holder. These For example, it is a cylindrical pressure vessel, so an annular holder is located on the inner wall of the pressure vessel at. The holder is usually fixed to the pressure vessel be connected and flexible in their circular interior Pick up the membrane. The bracket ensures a seal of the both areas on both sides of the membrane and thus for a separation of the two media. Will be on one side of the membrane a compressed gas admitted, so it turns conditional the membrane curvature in the pressurized fluid, z. B. the hydraulic fluid, the same pressure. The consequence is that after refueling with compressed gas, z. As natural gas, the hydraulic or pneumatic drive immediately available. A separate pump for compressing of the pressure fluid is thus saved.

In a further embodiment has the pressure vessel a first opening for the compressed gas and a second opening for the pressurized fluid in one balloon-shaped membrane. The two media thus arrive over different openings in the pressure vessel, wherein the opening of the balloon-shaped membrane in a the two openings is fitted. Is the balloon-shaped Membrane, for example, with the pressurized fluid for the hydraulic or pneumatic drive is filled and will be in the rest Area of the pressure vessel the compressed combustible gas let in, the membrane contents are also subjected to pressure. In this case, the hydraulic or pneumatic drive stands immediately available without the compressed fluid first compressed separately becomes. A separate pump for compressing the pressurized fluid will therefore not needed.

In a further embodiment has the pressure vessel in its interior another container, on its inner wall the (membrane) holder clings longitudinally displaceable. The additional container can be made of stainless steel and be made sufficiently smooth to a corresponding sliding to allow the holder. He allows the Choice of a less flexible membrane material, in which the room layout in the pressure vessel on the one hand by the membrane curvature and additionally by a longitudinal displacement of Bracket is made. In the limiting case, the choice of a largely rigid membrane before adjustable, so that the room layout almost completely over the longitudinal displacement of the holder takes place. The nestling the holder to the inner wall of the additional container ensures the required separation of pressure fluid and compressed gas.

In Another embodiment has the drive unit to a first pressure sensor for the compressed gas, a second pressure sensor for the pressurized fluid and a controllable Valve in a pressurized fluid line between the pressure vessel and a (pressure) surge tank. A control unit regulates the flow of pressurized fluid through the valve in dependence the measured values of the first and the second pressure sensor.

The control receives as input values data that depict current or future vehicle and traffic situations and that are available or made available to the vehicle. These data are either in-vehicle data or come from intelligent systems with external connection, eg. B. via navigation to the vehicle environment. Examples are the speed, the Be Acceleration, the expected or optimal distance and the driving style of the driver (eg position of accelerator or brake, driving program of an automatic vehicle), driving restrictions z. B. in the form of speed limits or emission limits, etc. and the drive data (system readiness, drive power, stored energy, available energy / drive power, etc. Based on these data is calculated for the selected driving profile or program optimal energy use of the available drive units and the respective The above-mentioned valve is also regulated using the measured values of the pressure sensors Constant evaluation of the sensor, drive and surrounding data enables constant optimization and adjustment of the control, or when using adaptive self-learning control continuous optimization of the control even over longer periods of time, for example to compensate for aging or wear processes or to take better account of typical driver or situational characteristics.

One second aspect of the invention relates to a motor vehicle, in particular a passenger car, with a drive unit according to one of the embodiments described above.

The Motor vehicle with this drive unit has in one embodiment as the primary machine the first drive. The second drive, So the hydraulic or pneumatic drive is only as an auxiliary drive thought. The range of the motor vehicle with exclusive Use of the second drive or auxiliary drive is maximum 50 km.

For The above control unit can be a separate electronic Be provided control unit, which only the position of the valve in the pressure fluid line between pressure vessel and expansion tank regulates. Alternatively, this can be a logic unit of a Antilock braking system or the on-board computer can be selected become.

Further Features and advantages of the claimed invention will be apparent from the following detailed description with reference to the attached Drawings recognizable below as non-limiting Examples are given. Here, the use of reference numerals in the figures not to be understood that the reference numerals limit the scope of the claimed invention should. Show it:

1 a drive unit according to an embodiment of the invention,

2a to 2c Embodiments of a pressure vessel for the drive unit according to 1 ,

In the figures, which generally denote like objects with like reference numerals, shows 1 a drive unit 1 according to an embodiment of the invention. This includes a first drive 2 for burning compressed natural gas stored in a pressure vessel 3 is stored. The pressure vessel 3 continues to take the pressurized fluid in a car wheel 4 or alternatively a motor vehicle drive axle or a motor vehicle drive (motor or gearbox) integrated second drive 5 in the form of hydraulic drive. The pressurized fluid can for this purpose from the pressure vessel 3 through the pressure fluid line 6 to the second drive 5 flow, with a (pressure) surge tank 7 is used to provide low pressure. A separate logic unit 8th regulates the flow through the valve 9 in the pressure fluid line 6 depending on measured values of the pressure sensors 10 and 11 , which are associated with the compressed natural gas or the pressure fluid.

2a shows an embodiment of a pressure vessel 3 with a first opening 12 for admitting a compressed combustible gas 13 and a second opening 14 for introducing a pressurized fluid 15 such as For example, oil. The compressed gas 13 and the pressurized fluid 15 are through a membrane 16 separated from each other. The membrane 16 of the cylindrical pressure vessel 3 is from an annular holder 17 edged on the inner wall 18 of the pressure vessel 3 is attached. Depending on the pressure conditions in the two media is due to the flexible membrane material a certain curvature of the membrane 16 one. This allows the membrane 16 compensate for the pressure difference between the two media and is itself not significantly under pressure. Will the flammable gas 13 through the first opening 12 let in, it also builds up in the pressure vessel area to the right of the membrane 16 a pressure, so that for the pressure fluid located there 15 no separate pump is required.

insofar is after refueling the vehicle, the hydraulic drive without further action available.

2 B shows a further embodiment of the pressure vessel, in which a balloon-shaped membrane 16 is provided. The opening of the membrane 16 is from the second opening 14 bordered so that of a pressure fluid line, not shown here 6 over the second opening 14 the pressurized fluid 15 into the balloon-shaped membrane 16 can flow in. Will over the first opening 12 the vehicle with combustible gas 13 fueled, so there is an equal pressure for the pressurized fluid 15 within the balloon-shaped membrane 16 , In this embodiment as well, there is no separate pump for the pressurized fluid 15 required.

2c shows a further embodiment of the pressure vessel 3 , In this is another container 19 made of stainless steel, which in its interior a longitudinally displaceable holder 17 for a membrane 16 has. At a pressure difference between the compressed gas 13 and the pressurized fluid 15 shifts the position of the bracket 17 along the inner wall 20 until a pressure equalization occurs. In this way, a less flexible membrane material can be used.

In practical use, the flow of pressurized fluid 15 in the pressure fluid line 6 with a controllable valve 9 regulated, that of the control unit 21 is controlled. At the control unit 21 It can be an electronic logic unit that only uses the valve 9 controls, or it may be the logic of the drive unit or an anti-lock braking system or the on-board computer.

Even though concrete embodiments have been described above, The person skilled in the art will recognize that the description of these embodiments does not have the purpose to limit the invention in the form specified. Rather, the invention is intended to be all modifications, equivalents and include alternatives that are within the scope of the claimed claims Fall invention.

1

drive unit

2

first drive

3

pressure vessel

4

Automotive wheel

5

second Drive / hydraulic drive

6

Pressure fluid line

7

surge tank

9

Valve

10

pressure sensor

11

pressure sensor

12

first opening

13

compressed gas

14

second opening

15

pressure fluid

16

membrane

17

bracket

18

inner wall

19

container

20

inner wall

21

control unit

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

• - JP 2002067712 [0003]
• - DE 10201930 A1 [0004]

Claims (10)

Drive unit ( 1 ) for a motor vehicle, in particular a passenger car, comprising a) a first drive ( 2 ), for which a compressed combustible gas ( 13 ) is provided as fuel, b) a second, with a pressurized fluid ( 15 ) equipped hydraulic or pneumatic drive ( 5 ), wherein a common pressure vessel ( 3 ) is provided for the compressed gas and the pressurized fluid. Drive unit according to claim 1, for the first Drive compressed natural gas is provided as a drive. Drive unit according to one of the preceding claims, in which a membrane ( 16 ) is provided for the separate holding of compressed gas and pressurized fluid in the pressure vessel. Drive unit according to one of the preceding claims, in which the diaphragm is attached to the inner wall ( 18 ) of the pressure vessel arranged holder ( 17 ) assigned. Drive unit according to one of the preceding claims, wherein for the pressure vessel, a first opening ( 12 ) for the inlet of compressed gas and a second opening ( 14 ) are provided for the inlet of the pressurized fluid into a balloon-shaped membrane. Drive unit according to one of the preceding claims, the pressure vessel in its interior another container ( 19 ), on whose inner wall ( 20 ) a membrane associated with the holder ( 17 ) hugs longitudinally. Drive unit according to one of the preceding claims, having a) a first pressure sensor ( 10 ) for the compressed gas, b) a second pressure sensor ( 11 ) for the pressurized fluid, c) an adjustable valve ( 9 ) in a pressurized fluid line ( 6 ) between the pressure vessel and an expansion tank ( 7 ), d) a control unit ( 21 ) to regulate the flow of pressurized fluid through the valve in response to the measurements of the first and second pressure sensors. Motor vehicle, in particular passenger car, with a drive unit according to one of the preceding claims. Motor vehicle according to claim 8, whose range maximum when using only the second drive 50 km. Motor vehicle according to one of the preceding claims, in which the control unit is a separate electronic control unit, the logic of the drive unit, a logic of an anti-lock braking system or an on-board computer is provided.