Method for diagnosing a fuel tank vent valve

• US 9,945,330 B2
• Filed: 05/13/2015
• Issued: 04/17/2018
• Est. Priority Date: 05/13/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Meinken, Andreas, Bruestle, Simon, Wieczorek, Thomas, Kastner, Johannes, Deibele, Bernhard
• Primary Examiner(s): Le, Toan
• Application Number:
  US14/711,247
• Publication Number:
  US 20150328980A1
• Time in Patent Office: 1,070 Days
• CPC Class Codes: B60K 15/03519 Valve arrangements in the vent line
• CPC Class Codes: B60K 2015/03328 Arrangements or special measures related to fuel tanks or fuel handling
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system

Abstract

A method for diagnosing a fuel tank vent valve of a motor vehicle. In the method it is inferred, from a curve of a pressure p over time in a sub-chamber of the motor vehicle after a start-up of an internal combustion engine of the motor vehicle, as to whether the fuel tank vent valve is jammed open. The sub-chamber contains a fuel tank of the motor vehicle and is delimited by the fuel tank vent valve.

Claims

1. A method of a fuel tank system of a motor vehicle, the method comprising:

in response to passage of a predefined time period after a start up of an internal combustion engine of the motor vehicle, a control unit of the system performing a control to open a fuel tank vent valve arranged between a sub-chamber that includes a fuel tank and an intake manifold;

sensing, by a pressure sensor, a pressure p in the sub-chamber throughout the predefined time period;

producing, by the pressure sensor, output signals corresponding to the sensed pressure p;

determining, by the control unit and based on the signals output by the pressure sensor, that the pressure p dropped during the predefined time period prior to the control to open the fuel tank vent valve; and

outputting, by the control unit, an error signal indicating that the fuel tank vent valve is jammed open in response to the determination that the pressure p dropped during the predefined time period prior to the control to open the fuel tank vent valve.

2. The method as recited in claim 1, wherein the sub-chamber includes an activated carbon filter of the motor vehicle, a line which connects the fuel tank to the activated carbon filter, and a line which connects the activated carbon filter to the fuel tank vent valve.

3. The method as recited in claim 1, wherein no activation of the fuel tank vent valve takes place during the predefined time period.

4. The method as recited in claim 1, wherein:

the motor vehicle has a start/stop function; and

the determining is performed each time the internal combustion engine is restarted.

5. A non-transitory computer-readable medium on which are stored instructions that are executable by an electronic control unit of a fuel tank system of a motor vehicle and that, when executed by the electronic control unit, cause the control unit to perform a method, the method comprising:

in response to passage of a predefined time period after a start up of an internal combustion engine of the motor vehicle, performing a control to open a fuel tank vent valve arranged between a sub-chamber that includes a fuel tank and an intake manifold;

obtain, from a pressure sensor, signals corresponding to a pressure p in the sub-chamber sensed by the pressure sensor throughout the predefined time period;

determining, based on the signals output by the pressure sensor, that the pressure p dropped during the predefined time period prior to the control to open the fuel tank vent valve; and

outputting an error signal indicating that the fuel tank vent valve is jammed open in response to the determination that the pressure p dropped during the predefined time period prior to the control to open the fuel tank vent valve.

6. An engine system of a motor vehicle, the system comprising:

an internal combustion engine;

a sub-chamber including a fuel tank and a pressure sensor;

an intake manifold;

a fuel tank vent valve arranged between the sub-chamber and the intake manifold; and

an electronic control unit;

wherein;

the electronic control unit is configured to, in response to passage of a predefined time period after a start up of the internal combustion engine, perform a control to open the fuel tank vent valve;

the pressure sensor is configured to sense a pressure p in the sub-chamber throughout the predefined time period and produce output signals corresponding to the sensed pressure p;

the control unit is configured to;

determine, based on the signals output by the pressure sensor, whether the pressure p dropped during the predefined time period prior to the control to open the fuel tank vent valve; and

where a result of the determination is positive, output an error signal in response to the determination, the error signal indicating that the fuel tank vent valve is jammed open; and

the system is arranged so that, where the fuel tank vent valve is not jammed open, the pressure p does not drop during the predefined time period from a time of the start up of the internal combustion engine, and the pressure p drops in response to the fuel tank vent valve opening due to the control performed in response to the passage of the predefined time period.