1. An apparatus for the self-diagnosis of an exhaust gas probe (20), the exhaust gas probe (20) having at least one heating element (26) and the exhaust gas probe (20) being connected to a controller, and the controller having devices for the diagnosis of the exhaust gas probe (20), characterized in that the controller has at least one calculating unit for the determination, in a modeled manner, of a parameter which denotes the correct operation of the exhaust gas probe (20), this parameter determined from parameters of the gas stream, and comparing said parameter with a measured parameter by means of at least one evaluation unit which is integrated into the controller, and determining the exhaust gas probe (20) is defective when a deviation exceeds a defined tolerance limit, or determining a faulty condition exists in an exhaust gas section (17), in which the exhaust gas probe (20) is installed.
2. An apparatus according to claim 1, characterized in that the parameter which is defined in a modeled manner, is compared with the measured parameter is the heat output PH of the heating element (26) of the exhaust gas probe (20).
3. An apparatus according to claim 2, characterized in that the exhaust gas probe (20) is configured as a particle sensor for determining a soot loading in the gas stream.
4. An apparatus according to claim 1, characterized in that the controller is one of an engine controller (14) of an internal combustion engine (10) or a sensor control unit.
5. An apparatus according to claim 1, characterized in that the parameter which denotes correct operation of the exhaust gas probe (20) is determined from boundary conditions of the gas stream or from measured parameters of the gas stream.
6. A method for the self-diagnosis of an exhaust gas probe (20), the exhaust gas probe (20) having at least one heating element (26), characterized in that a modeled heat output PH is determined for the heating element (26) by means of a computer program comparing parameters of the gas stream with a measured heat output, and determining, when the parameters of the gas stream exceeds the measured heat output by more than a defined tolerance limit, that one of the exhaust gas probe (20) is defective, and an exhaust gas section (17) in which the exhaust gas probe (20) is installed is faulty.
7. A method according to claim 6, characterized by determining the measured heat output PH from a heating current IH and a heating voltage UH applied to the heating element (26).
8. A method according to claim 7, characterized by using the heating voltage UH as a replacement variable.
9. A method according to claim 7, characterized by determining a heat output from an available supply voltage UBat and a maximum possible heating duty factor TVmax, and using the heat output as replacement variable.
10. A method according to claim 6, characterized by detecting, by a temperature measuring device in the exhaust gas probe (20), whether a setpoint temperature has been reached, and determining whether a deviation has been caused as a consequence of unfavorable operating conditions.
11. A method according to claim 6, characterized by determining additional variables beyond the heat output PH determined in a modeled manner, and using the determined additional variables for a comparison.
12. A method according to claim 6, characterized by subjecting input variables for the measured parameters for the gas stream to a filtering operation, and subsequently processing the input variables further to determine the modeled heat output.
13. A method according to claim 6, characterized by comparing temporal changes of the variables which are determined in a modeled manner with the measured variables or their changes.
14. A method according to claim 6, characterized by comparing an observed change in the heat output with a change in the parameters of the gas stream, and comparing a ratio of the change in the heat output and a change in the parameters of the gas stream with a threshold value.
15. A method according to claim 14, characterized in that the threshold is predefined or is variable based on a function of the parameters or the parameters which define the gas stream.
16. A method according to claim 6, characterized by determining a particle content in the gas stream using, as the exhaust gas probe (20), a particle sensor, and heating the particle sensor by means of the heating element (26) in a regeneration phase to remove a soot loading on the particle sensor.
17. A method according to claim 6, characterized in that the diagnosis is carried out during a phase having a constantly controlled temperature, or during a regeneration of the exhaust gas probe (20) having a heating ramp for achieving a free burning temperature required for soot elimination, or when the measured actual temperature deviates from an expected temperature setpoint value.
18. A method according to claim 6, characterized by determining the parameters of the gas stream from boundary conditions of the gas stream or from measured parameters of the gas stream.
19. A method according to claim 6, characterized in that the measured heat output PH is determined from a replacement variable.
20. A method for the self-diagnosis of an exhaust gas probe (20), the exhaust gas probe (20) having at least one heating element (26), characterized in that a modeled parameter is determined for the heating element (26) by means of a computer program comparing parameters of the gas stream with the modeled parameter, and determining, when the parameters of the gas stream exceeds the modeled parameter by more than a defined tolerance limit, that one of the exhaust gas probe (20) is defective, and an exhaust gas section (17) in which the exhaust gas probe (20) is installed is faulty.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A pressure-sensitive damper, comprising:
a first cylinder at least partially defining a first fluid chamber containing a damping fluid;
a damping piston supported for reciprocal motion within said first cylinder;
a piston rod having a first end connected to said damping piston, and a second end extending through a sealed opening in a seal head fixed to a first end of said first cylinder;
a second cylinder at least partially defining a second fluid chamber in selective fluid communication with said first cylinder and containing a damping fluid;
a compression damping plate fixed in said second cylinder;
at least one passage in said compression damping plate through which said damping fluid, displaced by the entrance into said first cylinder of successive portions of said piston rod during a compression stroke, flows in a first direction from said first fluid chamber to said second fluid chamber;
a first pressure source in communication with said second fluid chamber;
a valve which generates a resistance force to said fluid flow through said at least one passage in said first direction, wherein said resistance force varies according to an amount of force communicated to said valve by said first pressure source, said valve comprising:
a blow-off piston having a first position in engagement with said at least one passage and a second position removed from said at least one passage and,
an intensifier piston;
wherein said first pressure source acts on a first end of said intensifier piston, which generates an intensified pressure at the second end of said intensifier piston, and wherein said intensified pressure is communicated to said blow-off piston to create a force urging said blow-off piston toward said first position.
2. The damper of claim 1, further comprising a bypass circuit adapted to permit a flow of said damping fluid in said first direction through said compression damping plate without passing through said at least one passage.
3. The damper of claim 1, further comprising an externally-adjustable bypass circuit adapted to permit a flow of said damping fluid in said first direction through said compression damping plate without passing through said at least one passage.
4. The damper of claim 1, further comprising a second pressure source acting on said intensifier piston, said second pressure source adapted to generate a force tending to counteract said amount of force communicated to said valve by said first pressure source.
5. The damper of claim 4, wherein a pressure level of said second pressure source is adjustable.
6. The damper of claim 1, wherein a pressure level of said first pressure source is adjustable.
7. The damper of claim 1, wherein said first pressure source comprises a pressurized, compressible chamber containing compressible fluid.
8. The damper of claim 7, wherein said first pressure source additionally comprises an annular chamber with externally-adjustable volume.
9. The damper of claim 1, wherein the blow-off piston moves in an axial direction between the first position and the second position.
10. The damper of claim 9, wherein the blow-off piston and the intensifier piston move in the same direction.
11. The damper of claim 10, further comprising a third fluid chamber formed between the blow-off piston and the intensifier piston.
12. The damper of claim 11, wherein a diameter of the second end of said intensifier piston is smaller than an outer diameter of the blow-off piston.
13. The damper of claim 10, further comprising a shaft extending from the compression damping plate, wherein the intensifier piston is at least partially disposed in the shaft and moves relative to the shaft.
14. The damper of claim 13, wherein the blow-off piston comprises an annular piston disposed around the shaft.
15. The damper of claim 1, further comprising a second passage in the compression damping plate adapted to allow fluid flow from the second fluid chamber to the first fluid chamber.
16. The damper of claim 15, further comprising a one-way valve that permits fluid flow in the second direction through the second passage, but not the first direction.
17. A pressure-sensitive damper, comprising:
a first cylinder at least partially defining a first fluid chamber containing a damping fluid;
a damping piston supported for reciprocal motion within the first cylinder;
a piston rod having a first end connected to the damping piston and a second end extending through a first end of the first cylinder;
a second fluid chamber in selective fluid communication with the first fluid chamber;
a compression damping plate;
at least one fluid passage in the compression damping plate through which the damping fluid, displaced by the piston rod during a compression stroke, flows in a first direction from the first fluid chamber to the second fluid chamber; and
a valve which generates a resistance force to the fluid flow through the at least one passage in the first direction, wherein the resistance force varies according a pressure force generated in the damping fluid and communicated to the valve during the compression stroke;
a blow-off piston movable from a first position that substantially closes the at least one passage to a second position that opens the at least one passage; and an intensifier piston configured to generate an intensified pressure at a second end in response to the pressure force acting on a first end, wherein the blow-off piston comprises an annular piston disposed around a shaft extending from the compression damping plate, and wherein the intensified pressure urges the blow-off piston toward the first position.
18. A method of controlling damping, comprising:
displacing a damping fluid from a first chamber to a second chamber via a first passage during a compression stroke;
increasing a pressure in the second chamber;
applying a force to a first end of an intensifier piston located in the second chamber;
generating an intensified pressure at a second end of the intensifier piston in response to the force applied at the first end;
moving a blow-off piston to close fluid flow through the first passage in response to the intensified pressure; and
flowing the damping fluid from the second chamber to the first chamber via a second passage.