Vehicle having an internal combustion engine operated by means of a gas

Abstract

The invention relates to a vehicle (1) having an internal combustion engine operated by means of a gas, wherein the gas is stored under pressure in a gas tank (5) and is fed to the internal combustion engine as needed for the operation of the internal combustion engine and a safety device having a pressure relief valve (7) is provided, which safety device becomes active when a specified discharge gas pressure is exceeded in the gas tank (5). According to the invention, a vehicle (1) and a method for operating a gas-operated vehicle having an improved safety device for gas discharged from a gas tank (5) when a discharge gas pressure is exceeded are specified. This is achieved in that the safety device comprises a burner (9) for burning off the discharged gas and that it is determined beforehand whether the vehicle is outdoors or in a hall.

Claims

1. A vehicle (1) having an internal combustion engine operated by means of a gas, wherein the gas is stored under pressure in a gas tank (5) for feeding the gas to the internal combustion engine as needed for the operation of the internal combustion engine, the vehicle comprising: two light sensors (12a, 12b), a safety device having a pressure relief valve (7) for a release of gas from the gas tank (5) and having a burner for flaring released gas, wherein the pressure relief valve opens when a specified discharge gas pressure is exceeded in the gas tank (5), and a control unit (10) for operating the burner, wherein the control unit (10) determines whether the vehicle (1) is located outdoors or indoors based on signals from light sensors (12a, 12b), the control unit being configured to actuate the burner when a gas pressure inside the gas tank (5) exceeds the specified discharge gas pressure.

2. The vehicle (1) as claimed in claim 1, characterized in that the burner (9) includes an ignition device.

3. The vehicle (1) as claimed in claim 1, further comprising a temperature sensor (13) for supplying a signal to the control unit (10).

4. The vehicle (1) as claimed in claim 1, characterized in that the light sensors (12a, 12b) are disposed on an exposed area of the vehicle (1) that is unprotected from an environment.

5. The vehicle (1) as claimed in claim 1, further comprising an acoustic signal generator (14) controlled by the control unit (10) in the event of the operation of the burner (9).

6. The vehicle (1) as claimed in claim 1, further comprising an oxygen measuring device connected to the control unit.

7. A method for operating a vehicle (1), having an internal combustion engine operated by means of a gas, wherein the gas is stored under pressure in a gas tank (5) for feeding the gas to the internal combustion engine as needed for the operation of the internal combustion engine, the method comprising; determining whether the vehicle (1) is located outdoors or indoors by evaluating signals from light sensors (12a, 12b) and from a temperature sensor (13), and providing a safety device having a pressure relief valve (7) and a burner, wherein the pressure relief valve opens when a specified discharge gas pressure is exceeded in the gas tank (5), and wherein, when the specified discharge gas pressure is exceeded, the gas released via the pressure relief valve (7) is flared in the burner (9).

8. The vehicle (1) as claimed in claim 4, wherein the exposed area of the vehicle (1) is a roof (8) of the vehicle (1).

9. The vehicle (1) as claimed in claim 3, characterized in that the temperature sensor (13) is disposed on an exposed area of the vehicle (1) that is unprotected from an environment.

10. The vehicle (1) as claimed in claim 9, wherein the exposed area of the vehicle (1) is a roof (8) of the vehicle (1).

11. The vehicle (1) as claimed in claim 9, wherein the control unit determines whether the vehicle is indoors or outdoors based in part on fluctuation of a light intensity measured by the light sensors.

12. The vehicle (1) as claimed in claim 5, wherein the control unit activates the acoustic signal generator (14) when the control unit (10) determines the vehicle is indoors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments of the invention can be appreciated from the description of the drawing, in which an illustrative embodiment of the invention represented in the figures is described in more detail.

(2) In the drawing:

(3) FIG. 1 depicts a schematic side view of a vehicle having a gas-powered internal combustion engine with a safety device embodied according to the invention, and

(4) FIG. 2 depicts a schematic view of a roof of a vehicle having sensors disposed thereon.

DETAILED DESCRIPTION

(5) FIG. 1 depicts a purely schematic side view of a vehicle, which may be a tractor unit of a commercial vehicle, for example. The vehicle 1 has a frame 15 with a rear wheel axle 2 and a front wheel axle 3, wherein a driver's cab 4 is disposed above the front wheel axle 3 and is secured to the frame 15. Installed in the vehicle 1 is an internal combustion engine (not illustrated here), which is operated by means of a gas, for example methane, stored in a gas tank 5. The gas in this case (after removal from the gas tank 5) can be supplied to the internal combustion engine in a liquid or gaseous state. This will depend on the gas and/or the control of the corresponding injection system. The internal combustion engine interacts with the rear axle 2, for example via a transmission, in order to propel the vehicle 1.

(6) The gas is stored in the liquid state in the gas tank 5. In the event of the vehicle 1 being left standing for a longer period under the effect of solar radiation on the gas tank 5, a positive pressure may occur inside the gas tank 5, which positive pressure arises as a consequence of the vaporization of the liquid gas. A safety device, which comprises a discharge line 6 having a pressure relief valve 7 interacting with the gas tank 5, is provided in order to prevent an unacceptably high increase in pressure inside the gas tank 5. As an alternative, the pressure relief valve 7 can also be integrated into the gas tank 5. The discharge line 6 is routed upwards as far as a roof 8 of the driver's cab 4, for example, and in this region has a burner 8 with an integrated ignition device. A control unit 10, which in particular controls the operation of the burner 9, is also disposed at an appropriate point on the vehicle, for example inside the driver's cab 4. Signals from a pressure sensor 11 and from light sensors 12a, 12b disposed in the region of the roof 8 and from a temperature sensor 13 (see also FIG. 2), are supplied to the control unit 10. The light sensors 12a, 12b are arranged spaced apart from one another either directly on the roof 8 or on a device arranged on the roof, for example a spoiler, so that said light sensors receive different light signals when the vehicle 1 is parked under a moving covering, as in the case of a tree, for example, having leaves that are caused to move by the wind.

(7) The function of the inventive system is described below.

(8) The pressure sensor 11 detects inside the gas tank 5 a gas pressure, which has a value of approximately 80% of a specified gas discharge pressure, for example, at which the pressure relief valve 7 admits gas into the discharge line 6. This gas pressure, which is higher compared with the normal gas pressure, arises in particular in the event of solar radiation on the gas tank 5, in conjunction with which the stored liquid gas is heated and is increasingly vaporized as a result of the solar radiation. In this first operating condition, the control unit 10 is activated by the light sensors 12a, 12b and the temperature sensor 13, which control unit evaluates the signals received from the light sensors 12a, 12b and the signal from the temperature sensor 13 over a period of time. If, for example, the signals received from the light sensors 12a, 12b are almost identical, and the signal received from the temperature sensor 13 is reasonably constant, it may be assumed that the vehicle 1 is parked in a hangar, for example, into which the solar radiation penetrates (for example through a glass roof). If, however, in particular the values received from the light sensors 12a, 12b differ from one another and/or if the signals received from the temperature sensor 13 over a specified interval of time, for example of one day or two days, exhibit clearly different values, it may be assumed that the vehicle is standing in the open, for example under a tree or a bridge. The information obtained in this way is used to control the burner and/or an acoustic signal generator 14.

(9) The control unit 10 thus ensures, in the event of a further increase in the pressure of the gas inside the gas tank 5, and in the event of reaching the specified gas discharge pressure, at which the pressure relief valve 7 opens automatically and admits gas from the gas tank 5 into the discharge line 6, that the ignition device of the burner 9 is operated and ignites the gas flowing into the burner 9, so that said gas is flared in a controlled manner by the addition of oxygen (ambient air). No harmful impact on the environment thus results from the mixing of a gas considered to be a greenhouse gas, for example methane, with the ambient air.

(10) At least ifas previously mentionedit is determined that the vehicle 1 is standing in a hangar, an acoustic signal is generated additionally by the signal generator 14, which signal informs of possible hazards, which are caused in particular as a result of the removal of oxygen inside the hangar and as a result of the exhaust gases that are produced in the course of the flaring operation. In order to compensate for the removal of oxygen, the oxygen that is required for combustion can be taken from a compressed air reservoir, which is installed in the vehicle.