CATALYTIC CONVERTER HEATING ELEMENT

Abstract

A method of controlling a heating element for providing heat to a catalyst of a catalytic converter, the method comprising: determining a catalyst performance characteristic as a function of time, and varying the amount of heating provided by the heating element in response to a change in the catalyst performance characteristic being greater than a predetermined amount.

Claims

1. A method of controlling a heating element for providing heat to a catalyst of a catalytic converter, wherein the catalytic converter is configured to be coupled to an engine, the method comprising: determining a catalyst performance characteristic as a function of time, wherein the catalyst performance characteristic comprises a value indicating a number of hours the engine has run; determining whether the value indicating the number of hours the engine has run has increased above a threshold value; and in response to determining that the value indicating the number of hours the engine has run has increased above the threshold amount value, varying the amount of heating provided by the heating element.

2. The method of claim 1, wherein the catalyst performance characteristic comprises a catalyst oxygen storage value, the method further comprising: determining whether the catalyst oxygen storage value has decreased with respect to a stored catalyst oxygen storage value; and in response to determining that the catalyst oxygen storage value has decreased, instructing the heating element to provide more heat to the catalyst.

3. The method of claim 1, wherein the catalyst performance characteristic comprises first and second catalyst oxygen sensor values, the first catalyst oxygen sensor value corresponding to a first end of the catalyst and the second catalyst oxygen sensor value corresponding to an opposing second end of the catalyst, the method further comprising: determining a difference between the first catalyst oxygen sensor value and the second catalyst oxygen sensor value; determining whether the difference between the first catalyst oxygen sensor value and the second catalyst oxygen sensor value has decreased with respect to a stored catalyst oxygen sensor difference value; and in response to determining that the difference between the first catalyst oxygen sensor value and the second catalyst oxygen sensor value has decreased, instructing the heating element to provide more heat to the catalyst.

4. The method of claim 1, wherein the catalyst performance characteristic comprises a temperature value, the method further comprising: determining whether the temperature value has decreased with respect to a stored temperature value; and in response to determining that the temperature value has decreased, instructing the heating element to provide more heat to the catalyst.

5. The method of claim 1, wherein the catalyst performance characteristic comprises an accumulated catalyst usage value, the method further comprising: determining whether the accumulated catalyst usage value has increased above a threshold value; and in response to determining that the accumulated catalyst usage value has increased above the threshold value, instructing the heating element to provide more heat to the catalyst.

6. The method of claim 1, wherein the catalytic converter is part of a vehicle and the catalyst performance characteristic comprises a value indicating a distance travelled by the vehicle, the method further comprising: determining whether the value indicating the distance travelled by the vehicle has increased above a threshold value; and in response to determining that the value indicating the distance travelled by the vehicle has increased above the threshold value, instructing the heating element to provide more heat to the catalyst.

7. The method of claim 1, wherein the catalyst performance characteristic comprises a value indicating a number of hours the engine has run, the method further comprising, in response to determining that the value indicating a number of hours the engine has run has increased above the threshold amount, instructing the heating element provide more heat to the catalyst.

8. A method of controlling a heating element for providing heat to a catalyst of a catalytic converter, the heating element comprising a plurality of independently controllably electrical elements, the method comprising: controlling a first electrical element of the plurality of electrical elements to provide heat to a first part of the catalyst; controlling a second electrical element of the plurality of electrical elements to provide heat to a second part of the catalyst; determining a catalyst performance characteristic as a function of time; and varying an amount of heating provided by at least one of the first electrical element and the amount of heating provided by the second electrical element in response to a change in the catalyst performance characteristic being greater than a predetermined amount.

9. The method of claim 8, wherein the catalyst performance characteristic comprises first and second catalyst oxygen storage values, the first catalyst oxygen storage value corresponding to a first end of the catalyst and the second catalyst oxygen storage value corresponding to an opposing second end of the catalyst, the method further comprising: determining whether the first catalyst oxygen storage value has decreased with respect to a first stored catalyst oxygen storage value; determining whether the second catalyst oxygen storage value has decreased with respect to a second stored catalyst oxygen storage value; in response to determining that the first catalyst oxygen storage value has decreased, instructing the first electrical element to provide more heat to the first end of the catalyst; and in response to determining that the second catalyst oxygen storage value has decreased, instructing the second electrical element to provide more heat to the second end of the catalyst.

10. The method of claim 8, wherein the catalyst performance characteristic comprises first and second catalyst temperature values, the first catalyst temperature value corresponding to a first end of the catalyst and the second catalyst temperature value corresponding to an opposing second end of the catalyst, the method further comprising: determining whether the first catalyst temperature value has decreased with respect to a first stored temperature storage value; determining whether the second catalyst temperature value has decreased with respect to a second stored catalyst temperature storage value; in response to determining that the first catalyst temperature value has decreased, instructing the first electrical element to provide more heat to the first end of the catalyst; and in response to determining that the second catalyst temperature value has decreased, instructing the second electrical element to provide more heat to the second end of the catalyst.

11. A heating element for providing heat to a catalyst of a catalytic converter, the heating element comprising a plurality of independently controllable electrical elements configured, in use, to provide a first electrical element of the plurality of electrical elements a first amount of heat to a first part of the catalyst and a second electrical element of the plurality of electrical elements can provide a second amount of heat to a second part of the catalyst, the heating element comprising a memory storing instructions and control circuitry communicably coupled to the memory and configured to execute instructions to vary an amount of heating provided by at least one of the first electrical element, in use, and the amount of heating provided by the second electrical element, in use, in response to a change in a determined catalyst performance characteristic being greater than a predetermined amount.

12. The heating element of claim 11, wherein the catalytic converter comprises an insulating material and at least a part of the heating element is embedded the insulating material.

13. The heating element of claim 11, wherein the catalytic converter comprises an insulating material and at least a part of the heating element is attached to a surface of the insulating material.

14. An exhaust system comprising the heating element of claim 11.

15. A vehicle comprising the heating element of claim 11.

Description

FIGURES

[0025] The above and other objects and advantages of the disclosure will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0026] FIG. 1 shows method steps, in accordance with an example of the disclosure.

[0027] FIG. 2 shows method steps, in accordance with an example of the disclosure.

[0028] FIG. 3 shows method steps, in accordance with an example of the disclosure.

[0029] FIG. 4 shows method steps, in accordance with an example of the disclosure.

[0030] FIG. 5 shows method steps, in accordance with an example of the disclosure.

[0031] FIG. 6 shows a schematic diagram of a catalytic converter, a support mat and heating elements for providing heat to a catalyst of a catalytic converter, in accordance with an example of the disclosure.

[0032] FIG. 7 shows a schematic diagram of a catalytic converter, heating elements and a control system for providing heat to a catalyst of a catalytic converter, in accordance with an example of the disclosure.

[0033] FIG. 8 shows a schematic diagram of a vehicle and an exhaust system having a heating element for providing heat to a catalyst of a catalytic converter, in accordance with an example of the disclosure.

[0034] FIG. 1 describes a method 100 of controlling a heating element for providing heat to a catalyst of a catalytic converter. At 102 a catalyst performance characteristic, as a function of time, is determined. At 104, the amount of heating provided by the heating element is varied in response to a change in the catalyst performance characteristic being greater than a predetermined amount. In general, a catalyst performance characteristic is any value that can be measured and used to infer a decrease in catalyst performance.

[0035] FIG. 2 describes a method 200 of controlling a heating element for providing heat to a catalyst of a catalytic converter. At 202 a catalyst performance characteristic, as a function of time, is determined, wherein the catalyst performance characteristic is at least one of: a decrease in a catalyst oxygen storage value with respect to a stored catalyst oxygen storage value, a decrease in a temperature value with respect to a stored temperature value, an increase in an accumulated catalyst usage value above a threshold value, an increase in a value indicating the distance travelled by a vehicle above a threshold amount, and an increase in a value indicating the number of hours that an engine has run above a threshold amount. At 204 the heating element is instructed to provide more heat to the catalyst in response to determining that the value has increased above the threshold value.

[0036] FIG. 3 describes a method 300 of controlling a heating element for providing heat to a catalyst of a catalytic converter. At 302 a catalyst performance characteristic, as a function of time, is determined, wherein the catalyst performance characteristic comprises first and second catalyst oxygen sensor values, the first catalyst oxygen sensor value corresponding to first end of the catalyst and the second catalyst oxygen sensor value corresponding to an opposing second end of the catalyst. At 304 a difference between the first catalyst oxygen sensor value and the second catalyst oxygen sensor value is determined. At 306 it is determined whether the difference between the first catalyst oxygen sensor value and the second catalyst oxygen sensor value has decreased with respect to a stored catalyst oxygen sensor difference value. At 308, in response to determining that the difference between the first catalyst oxygen sensor value and the second catalyst oxygen sensor value has decreased, the heating element is instructed to provide more heat to the catalyst.

[0037] FIG. 4 describes a method 400 of controlling a heating element for providing heat to a catalyst of a catalytic converter. At 402 a first electrical element of a plurality of electrical elements is controlled to provide heat to a first part of a catalyst. At 404 a second electrical element of the plurality of electrical elements is controlled to provide heat to a second part of a catalyst. At 406 a catalyst performance characteristic is determined, as a function of time. At 408 the amount of heating provided by the first electrical element and/or the amount of heating provided by the second electrical element is varied in response to a change in the catalyst performance characteristic being greater than a predetermined amount. In general, a catalyst performance characteristic is any value that can be measured and used to infer a decrease in catalyst performance.

[0038] FIG. 5 describes a method 500 of controlling a heating element for providing heat to a catalyst of a catalytic converter. At 502, a first electrical element of a plurality of electrical elements is controlled to provide heat to a first part of a catalyst. At 504, a second electrical element of the plurality of electrical elements is controlled to provide heat to a second part of a catalyst. At 506, it is determined whether a first catalyst oxygen storage value and/or a first catalyst temperature value has decreased with respect to a respective first stored catalyst oxygen storage value or first catalyst temperature value, wherein the first values correspond to a first end of the catalyst. At 508 it is determined whether a second catalyst oxygen storage value and/or a first catalyst temperature value has decreased with respect to a respective second stored catalyst oxygen storage value or second catalyst temperature value, wherein the second values correspond to a second end of the catalyst, the second end opposing the first end of the catalyst. At 510, in response to determining that the first catalyst oxygen storage value and/or the first catalyst temperature value has decreased, the first electrical element is instructed to provide more heat to the first end of the catalyst. At 512, in response to determining that the second catalyst oxygen storage value and/or the second catalyst temperature value has decreased, the second electrical element is instructed to provide more heat to the second end of the catalyst.

[0039] FIG. 6 is a schematic diagram of a catalytic converter 602, heating elements 604a and 604b, a control element and power supply 606 and a support element 608 for providing heat to a catalyst of a catalytic converter. Exhaust gases pass through and/or over the catalytic converter 602 as indicated by the arrows. The heating elements 604a and 604b are used to apply heat to the catalyst. In this example there are two heating elements 604, but there may be any number of heating elements, such as three, four, five or ten. The heating elements may be located at any surface of the catalytic converter. The heating elements may be controlled by instructions executed on a computing device comprising a memory and a processor. The heating elements may make use of resistive heating to heat the catalyst of the catalytic converter 602. In some examples, at least some of the heating elements may be located inside of the catalytic converter. The support element 608 may help to hold the catalytic converter 602 in place in the exhaust system, for example inside a can. The support element may be a support mat comprising fibers that are woven or compressed. The support mat may have insulating properties. The support element may encircle the catalytic converter such that all of or part of the surface of the catalytic converter is covered by the support mat. The heating element 604a is an example wherein the heating element 604a is embedded in the insulating material. The heating element 604b is an example wherein the heating element 604b is attached to a surface of the insulating material. Although the figure shows two different types of heating element 604a, 604b in conjunction with a single catalytic converter 602, examples where there are one or more heating elements of the same type (i.e. embedded in the insulating material or attached to the surface of the insulating material) are also contemplated.

[0040] FIG. 7 is a schematic diagram of a catalytic converter 700, heating elements 706 and a control system for providing heat to a catalyst 704 of the catalytic converter 700. Exhaust gases enter the catalytic converter 700 at a first end, pass through and/or over the catalyst 704 and exit the catalytic converter 700 at a second end as indicated by the arrows 702, 708. The heating elements 706 are used to apply heat to the catalyst 704. In this example there are eight heating elements 706, but there may be any number of heating elements, such as two, three, four, five or ten. The heating elements may be located at any surface of the catalytic converter.

[0041] In this example, an oxygen sensor and/or exhaust temperature sensor 710 monitors the exhaust gas that exits the catalytic converter 700. The output of the sensor 710 is communicated to a computing device comprising a memory and a processor, which executes instructions to implement a powertrain control strategy 712.

[0042] In some examples, greater heating is applied in the front area of the catalyst 704 with the heating progressively increased along the catalyst 704 as it ages. Such a heating strategy allows specific areas of the catalyst 704 to be heated to address relative aging of the catalyst 704, for example the part of the catalyst 704 that receives the exhaust gas flow may age faster than the part of the catalyst that is proximate the exhaust gas flow exit. In addition, based on the output from the exhaust temperature and/or the oxygen sensor 710, if the catalyst conversion efficiency starts to reduce due to cooling of the exhaust, additional heating could be applied by the heating elements 706 to the rear of the catalyst 704, which would typically be at an overall lower temperature compared to the front of the catalyst. This is due to the exhaust gases losing heat as they progress through/along the catalyst 704.

[0043] The computing device instructs the heating element control 714 to heat one or more of the heating elements 706 in accordance with the powertrain control strategy 712. Generally, a new catalyst will have a lower heating requirement than a relatively old catalyst. The amount of catalyst heating is determined by the computing device and is dependent on the output of the oxygen sensor and/or temperature sensor 710 and/or a model of catalyst aging that is implemented by the computing device.

[0044] FIG. 8 shows a schematic diagram of a vehicle 800 having an exhaust system 802 attached to an engine 804. The exhaust system 802 takes exhaust gases away from the engine 804 and comprises a catalytic converter. The catalytic converter has one or more heating elements for providing heat to a catalyst of the catalytic converter. The one or more heating elements may be as described above.

[0045] The processes described above are intended to be illustrative and not limiting. One skilled in the art would appreciate that the steps of the processes discussed herein may be omitted, modified, combined, and/or rearranged, and any additional steps may be performed without departing from the scope of the disclosure. More generally, the above disclosure is meant to be exemplary and not limiting. Furthermore, it should be noted that the features and limitations described in any one embodiment and/or example may be applied to any other embodiment and/or example herein, and flowcharts or examples relating to one embodiment and/or example may be combined with any other embodiment and/or example in a suitable manner, done in different orders, or done in parallel. In addition, the systems and methods described herein may be performed in real time. It should also be noted that the systems and/or methods described above may be applied to, or used in accordance with, other systems and/or methods.