Method for testing the function of a pressure switch of a tank ventilation system, control device, and internal combustion engine
First Claim
1. A method for testing the function of a pressure switch of a tank ventilation system for an internal combustion engine of a motor vehicle, the pressure switch being in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit, and the pressure switch being in a high-pressure position if that is not the case, wherein the method comprises the following steps:
- detecting a switched state of the pressure switch,carrying out a measure that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position, the measure including;
actuating a tank ventilation valve arranged in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine when the internal combustion engine is in operation such that the tank ventilation system and the intake pipe are pneumatically separated; and
determining whether conditions indicate a sufficient rise of pressure in the tank ventilation system for testing the function of the pressure switch, including at least one of;
determining whether a detected acceleration of the motor vehicle exceeds a predefined acceleration limit; and
determining whether a detected temperature of the motor vehicle exceeds a predefined temperature limit; and
identifying a defect of the pressure switch if the pressure switch remains in the low-pressure position after the measure has been carried out.
3 Assignments
0 Petitions
Accused Products
Abstract
The switched state of a pressure switch in a tank ventilation system of a motor vehicle is used for testing the function of the tank ventilation system, the pressure switch being in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit while being in a high-pressure position if that is not the case. A defective pressure switch can result in wrong assessments. Disclosed is a method for testing the function of the pressure switch, the method encompassing the following steps: a switched state of the pressure switch is detected; a measure is carried out that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position; a defect of the pressure switch is identified if the pressure switch remains in the low-pressure position after carrying out the measure.
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Citations
24 Claims
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1. A method for testing the function of a pressure switch of a tank ventilation system for an internal combustion engine of a motor vehicle, the pressure switch being in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit, and the pressure switch being in a high-pressure position if that is not the case, wherein the method comprises the following steps:
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detecting a switched state of the pressure switch, carrying out a measure that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position, the measure including; actuating a tank ventilation valve arranged in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine when the internal combustion engine is in operation such that the tank ventilation system and the intake pipe are pneumatically separated; and determining whether conditions indicate a sufficient rise of pressure in the tank ventilation system for testing the function of the pressure switch, including at least one of; determining whether a detected acceleration of the motor vehicle exceeds a predefined acceleration limit; and determining whether a detected temperature of the motor vehicle exceeds a predefined temperature limit; and identifying a defect of the pressure switch if the pressure switch remains in the low-pressure position after the measure has been carried out. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A control device for a motor vehicle which comprises a tank ventilation system, the tank ventilation system having a pressure switch that is in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit, and the pressure switch being in a high-pressure position if that is not the case, wherein the control device for testing the function of the pressure switch is operable:
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to detect a switched state of the pressure switch, to carry out a measure that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position, the measure including; actuating a tank ventilation valve arranged in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine when the internal combustion engine is in operation such that the tank ventilation system and the intake pipe are pneumatically separated; and determining whether conditions indicate a sufficient rise of pressure in the tank ventilation system for testing the function of the pressure switch, including at least one of; determining whether a detected acceleration of the motor vehicle exceeds a predefined acceleration limit; and determining whether a detected temperature of the motor vehicle exceeds a predefined temperature limit; and to identify a defect of the pressure switch if the pressure switch remains in the low-pressure position after the measure has been carried out. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An internal combustion engine for a motor vehicle which comprises a tank ventilation system, the tank ventilation system having a pressure switch that is in a low-pressure position if the pressure in the tank ventilation system is lower than a predefined pressure limit, and the pressure switch being in a high-pressure position if that is not the case, the internal combustion engine comprising:
a control device for testing the function of the pressure switch, the control device operable; to detect a switched state of the pressure switch, to carry out a measure that increases the pressure in the tank ventilation system above the pressure limit if the pressure switch is in the low-pressure position, the measure including; actuating a tank ventilation valve arranged in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine when the internal combustion engine is in operation such that the tank ventilation system and the intake pipe are pneumatically separated; and determining whether conditions indicate a sufficient rise of pressure in the tank ventilation system for testing the function of the pressure switch, including at least one of; determining whether a detected acceleration of the motor vehicle exceeds a predefined acceleration limit; and determining whether a detected temperature of the motor vehicle exceeds a predefined temperature limit; and to identify a defect of the pressure switch if the pressure switch remains in the low-pressure position after the measure has been carried out.
Specification