METHOD AND ELECTRIC VEHICLE WITH CO2 WARNING SYSTEM, AND USE OF A SENSOR SYSTEM THEREFORE

Abstract

A method for increasing safety in the surroundings of an electric vehicle having a fuel cell system and batteries, wherein the vehicle is configured for charging the batteries by power from the fuel cell system and e.g. produces CO2 during this operation, even when the vehicle is turned-off and in a parked situation, wherein the method includes the steps of providing a sensor system having a gas intake and configured for warning against elevated CO2 levels in the surroundings of the vehicle, mounting the sensor system on the vehicle with the gas intake outside the vehicle's cabin, providing an alarm when the sensor system evaluates that the CO2 levels in the surroundings of the vehicle are elevated and surpass a predetermined threshold level.

Claims

1. A method of increasing safety for the surroundings of an electric vehicle with a fuel cell system as well as batteries, wherein the vehicle is configured for charging the batteries by power from the fuel cell system also during a turned-off and parked situation, wherein the fuel cell system is configured for producing carbon dioxide, CO2, when in operation for electricity production, the method comprising providing a sensor system configured for warning against elevated CO2 levels in the surroundings of the vehicle, the sensor system comprising at least one of a carbon dioxide, CO2, sensor and an oxygen, O2, sensor; the sensor system having a gas in take, the sensor system being configured for correspondingly measuring at least one of CO2 and O2 levels in gas from the gas intake; mounting the sensor system on the vehicle with the gas intake outside the vehicle's cabin in order for the gas intake to have access to the air in the environment around the vehicle; then, using the sensor system for evaluating at least one of the CO2 concentration and the O2 concentration in gas from the gas intake relatively to a threshold value and warning against elevated CO2 levels in the surroundings of the vehicle by providing an alarm when the concentration surpasses a predetermined threshold level for the surroundings of the vehicle.

2. The method according to claim 1, wherein the method comprises arranging the gas intake of the sensor system at a height below 0.5 m from the ground.

3. The method according to claim 1, wherein the method comprises providing a remote device in wireless communication with the sensor system, the remote device being programmed to receive a wireless alarm signal from the sensor system and indicate this to a user of the remote device.

4. The method according to claim 1, wherein the sensor system comprises a CO2 sensor.

5. A vehicle comprising a fuel cell system as well as batteries, wherein the vehicle is configured for charging the batteries by power from the fuel cell system also during a turned-off and parked situation, wherein the fuel cell system is configured for producing carbon dioxide, CO2, when in operation for electricity production, the vehicle further comprising a sensor system configured for warning against elevated CO2 levels in the surroundings of the vehicle when the vehicle is in the parked situation and the fuel cell system is producing electricity for charging the batteries, the sensor system comprising at least one of a CO2 sensor and an O2 sensor; the sensor system having a gas intake outside the vehicle's cabin in order for the gas intake to have access to the atmosphere in the environment around the vehicle; wherein the sensor system is configured for measuring at least one of the CO2 concentration and O2 concentration in gas from the gas intake and for evaluating the concentration in gas from the gas intake relatively to a threshold value for the surroundings and for warning against elevated CO2 levels in the surroundings of the vehicle by providing an alarm when the concentration surpasses a predetermined threshold level.

6. The vehicle according to claim 5, wherein the gas intake of the sensor system is arranged at a height below 0.5 m from the ground.

7. The vehicle according to claim 5, wherein the vehicle comprises high temperature polymer electrolyte membrane HT-PEM fuel cells as part of the fuel cell system, the fuel cells configured for operating at a temperature in the range of 120-200° C., and wherein the vehicle is configured for providing evaporated fuel to the fuel cells, wherein the fuel is a mix of alcohol and water.

8. The vehicle according to claim 5, wherein the sensor system comprises a CO2 sensor.

9. Use of a sensor system on a fuel-cell driven vehicle for increasing safety against increased CO2 exposure in the surroundings of the vehicle when the fuel cell system is charging batteries during a turned-off and parked situation, the sensor system comprising at least one of a CO2 sensor and an O2 sensor for correspondingly measuring at least one of the CO2 concentration and O2 concentration during the parked situation, wherein the sensor system comprises an alarm function for the event that CO2 or O2 concentrations are measured that pass a predetermined threshold level for the surroundings.

Description

DESCRIPTION OF THE DRAWING

[0047] Embodiments of the invention will be described in the figures, wherein:

[0048] FIG. 1 a vehicle with a CO.sub.2 sensor

[0049] FIG. 2 a sensor in greater detail.

DETAILED DESCRIPTION OF THE INVENTION

[0050] FIG. 1 illustrates vehicle 1 containing a fuel cell 3 typically multiple fuel cells, for example as a stack of fuel cells, and batteries 2, which are electrically interconnected with the fuel cell in order for the fuel cell 3 to charge the batteries 2 during driving, in which the fuel cell 3 and the batteries 2 have a role as a hybrid power supply system.

[0051] However, optionally, the batteries 2 can also be charged by the electrical power produced by the fuel cell 3 during parking in order to have fully charged batteries 2 at the next starting of the vehicle 1.

[0052] Advantageously, the fuel cell 3 is a high temperature polymer electrolyte membrane (HT-PEM) fuel cell. Typically, high temperature fuel cells operate in the temperature range of 120-200° C., and thus are producing heat as well. For example, the fuel cell 3 operates at a temperature of 170-185° C. This operation temperature is held constant by a correspondingly adjusted flow of coolant in a cooling circuit through the fuel cell. For example, the temperature of the coolant at the coolant inlet of the fuel cell is in the range of 160° C. to 175° C.

[0053] Apart from the fuel cells 3, the fuel cell system 4 comprises a combination of a reformer and corresponding reformer burner, and a temperature regulation system, including the cooling circuit. In addition, a power management system is provided. Fuel is provided from a fuel tank 5. For example, the fuel tank 5 contains alcohol, optionally methanol, to which water is added prior to catalytic transformation in a reformer for providing it as hydrogen fuel to the fuel cell.

[0054] As an example, in the reformer, the mix of methanol CH.sub.3OH and water H.sub.2O is catalytically converted into hydrogen gas H.sub.2 and CO.sub.2. The mix of H.sub.2 and CO.sub.2 is then supplied as so-called syngas to the anode side of the fuel cell 3, typically fuel cell stack.

[0055] Air from the environment is sucked in and supplied at increased pressure, typically by using a compressor, to the cathode side of the fuel cell 3 in order to provide the necessary oxygen for the reaction with the hydrogen to produce water, after hydrogen ions H+ have passed the membrane from the anode side to the cathode side.

[0056] Optionally, an oxygen sensor is provided in the flow path of the air prior to entering the cathode side of the fuel cell system.

[0057] The CO.sub.2 from the catalysed fuel is passing through the fuel cell 3 and exits the system through the exhaust 6 of the vehicle 1. In a closed environment, this CO.sub.2 can cause danger for humans and animals inside the closed space, as it displaces the necessary oxygen.

[0058] As a safety measure, a sensor 7 is provided in a sensor system, which has an intake 8 that is provided in flow-connection with the surroundings for intake of air from the environment. Optionally, in order to provide a high degree of safety, the intake 8 is provided near the ground 9, for example closer than 0.7 to the ground or even closer than 0.5 cm to the ground 9.

[0059] As an example, a sensor 7 is provided, as illustrated in FIG. 2, which shows the back part of the vehicle 1 in greater detail.

[0060] If the CO.sub.2 level rises above a predetermined CO.sub.2 threshold and/or if the oxygen level decreases below a predetermined O.sub.2 threshold, an alarm is given, for example in the form of sound 11. Additionally or alternatively, a wireless signal 10 is sent, for example to a further alarm station and/or to a remote device, such as a mobile phone, in order for precautionary measures to be taken.

[0061] As mentioned above, the sensor system optionally uses an oxygen sensor of the fuel cell system so that no dedicated additional O.sub.2 sensor has to be installed. Instead, the output signal from the O.sub.2 sensor of the fuel cell system is branched into a control function which is programmed to cause an alarm in case of the measured O.sub.2 concentration in the air that is drawn in is falling below a predetermined O.sub.2 threshold level.

REFERENCE NUMBERS

[0062] 1 vehicle [0063] 2 battery [0064] 3 fuel cell [0065] 4 fuel cell system [0066] 5 tank [0067] 6 exhaust of vehicle [0068] 7 sensor [0069] 8 intake of sensor [0070] 9 ground [0071] 10 wireless alarm signal [0072] 11 audio alarm