Motor vehicle on-board diagnostics to distinguish degradation from tampering

• US 9,068,492 B2
• Filed: 11/04/2011
• Issued: 06/30/2015
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bogema, John Paul, Lyon, Peter Mitchell, Zimmerman, Bret Alan, Fagerman, Todd, Crompton, Todd
• Primary Examiner(s): Olszewski, John R
• Assistant Examiner(s): Do, Truc M
• Application Number:
  US13/289,907
• Publication Number:
  US 20130116881A1
• Time in Patent Office: 1,334 Days
• Field of Search: 701/1, 701/21, 701/29, 701/34, 701/36, 701/102, 701/103, 701/110
• US Class Current: 1/1
• CPC Class Codes: F01N 2550/05 Systems for adding substances into exhaust
• CPC Class Codes: F01N 2550/24 Determining the presence or absence of an exhaust treating device
• CPC Class Codes: F01N 2900/0416 using the state of a sensor, e.g. of an exhaust gas sensor
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: F02D 2041/228 Warning displays
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for responding to conditions detected in an on-board diagnostic unit of a motor vehicle and signaling degradation of a component of the motor vehicle. The method includes providing a first response if the conditions signal degradation of the component due to tampering, and providing a second response if the conditions signal degradation of the component not due to tampering.

Claims

1. A method comprising:

receiving data from first and second vehicle sensors;

determining, in an on-board diagnostic unit of the vehicle, whether conditions signal degradation of a vehicle component during tampering based on the data, said determining yielding a boolean result indicating tampering when affirmative;

debouncing the result asymmetrically;

providing a first response when the conditions signal degradation due to tampering; and

providing a second response when the conditions signal degradation not due to tampering.

2. The method of claim 1, wherein the determination is affirmative when the data from the first sensor is greater than a threshold above which the degradation is sufficient in degree to be caused by tampering.

3. The method of claim 2, wherein the determination is affirmative when it is determined, based on the data from a second sensor, that the degradation sufficient in degree to be caused by tampering occurred during circumstances consistent with tampering.

4. The method of claim 3 wherein an affirmative result is filtered with a longer time constant, and a negative result is filtered with a shorter time constant.

5. An on-board diagnostic unit for a motor vehicle comprising memory that encodes instructions readable by a processor and causes the processor to:

receive data from a sensor arranged downstream of an SCR stage in the vehicle;

compare the data to a threshold above which degradation of a component is sufficient in degree to be caused by tampering;

determine whether the degradation sufficient in degree to be caused by tampering occurred during circumstances consistent with tampering;

provide a first response when the degradation is sufficient in degree to be caused by tampering and occurred during circumstances consistent with tampering; and

provide a second response when the degradation is insufficient in degree to be caused by tampering or occurred during circumstances not consistent with tampering.

6. The unit of claim 5 wherein the instructions cause the processor to receive the data, compare the data, and determine whether the degradation occurred during circumstances consistent with tampering, all in one drive cycle of the motor vehicle.