GB2406947A - Detecting fluctuation in temperature compensated tyre pressure using two threshold values - Google Patents
Detecting fluctuation in temperature compensated tyre pressure using two threshold values Download PDFInfo
- Publication number
- GB2406947A GB2406947A GB0500628A GB0500628A GB2406947A GB 2406947 A GB2406947 A GB 2406947A GB 0500628 A GB0500628 A GB 0500628A GB 0500628 A GB0500628 A GB 0500628A GB 2406947 A GB2406947 A GB 2406947A
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- GB
- United Kingdom
- Prior art keywords
- air pressure
- temperature
- tire
- measured
- predetermined
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
- B60C23/02—Signalling devices actuated by tyre pressure
- B60C23/04—Signalling devices actuated by tyre pressure mounted on the wheel or tyre
- B60C23/0408—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
A method and system for the detection of pressure drop in a tyre where air pressure and temperature within a tyre (2, figure 1) are measured 32 by pressure and temperature sensors (4,6 figure 1). The measure air pressure is converted into a temperature compensated air pressure according to the measured temperature 36, a temporal fluctuation of the temperature compensated air pressure is determined, and an alerting signal produced by an alerting unit (22, figure 1) when the air pressure fluctuates in a predetermined way. The difference between a current and a previously determined compensated air pressure values is calculated 50. If the difference is greater than a first threshold value 52 it is stored together with the times of its determination 54. The sum of the stored differences within a predetermined time interval is calculated 56 and an alerting signal is produced 60 when the sum exceeds a second threshold value 58.
Description
1 2406947 Nlethod and system for the detection of a pressure drop in a
tire.
The present invention concerns a method and a system for the detection of a pressure drop in a tire.
From US Patent 5,895,846, upon which the preamble of the independent claims are being based, a vehicle tire monitoring system is know that: periodically measures the air pressure and temperature in the tire; corrects the measured temperature; and creates an alarm signal if the temperature corrected air pressure changes over time by more than a threshold amount.
The invention is based upon the objective of finding a method to more precisely note an undesired pressure drop in a tire that might result in the tire becoming unroadworthy.
In accordance with a first aspect of the present invention a method for the - detection of a pressure drop in a tire, during which method air pressure and temperature within a tire are measured, the measured air pressure is converted into a temperature A. compensated air pressure according to the temperature, a temporal fluctuation of the lo. temperature compensated air pressure is determined and an alerting signal is produced -..
when the air pressure fluctuates in a predetermined way, is characterized in that, the
difference between a current and a previously determined measured or compensated air : 20 pressure value is calculated and stored together with the times of its determination; and the sum of the stored differences within a predetermined time interval is calculated and c -. c an alerting signal is produced when the sum exceeds a predetermined second threshold value...DTD: A solution of the invention's task is obtained which works particularly safe and free of external influences because air pressure fluctuations are detected and evaluated over a long period of time.
Preferably, a time is determined for which the measured pressure drops below a predetermined air pressure limit and this time is displayed.
The methods according to the invention arc further developed in an advantageous way.
In accordance with a second aspect of the present invention a system for the detection of a pressure drop in a tire, containing: an air pressure sensor for detection of an air pressure in a tire, a temperature sensor for detection of a temperature in a tire, and an evaluating unit which receives sensor signals of and is connected to an alerting unit, whereby the evaluating unit converts measured air pressure values and temperature values into temperature compensated air pressure values and produces an alerting signal when the temperature compensated air pressure fluctuates in a predetermined way, is characterized in that, the evaluating unit stores the difference between a current and a previously determined measured or compensated air pressure value, together with the times of its determination; and calculates the sum of the stored differences within a predetermined time interval and produces an alerting signal when the sum exceeds a predetermined second threshold value.
A base structure of a system for the implementation of the method is provided.
Preferably, the evaluating unit determines the time for which the measured air pressure drops below an acceptable air pressure and this time is displayed.
The invention is suitable for the detection of a pressure drop in all types of pneumatic tires. It is especially suitable for vehicle tires, like passenger car tires, truck tires, motorcycle tires, etc. : ,.. The invention is explained by way of example below, in more detail and . . according to schematic drawings.
It shows: :' ': Figure I a modular display of a system according to the invention, :' 20 Figure 2 a flow chart detailing functionality of a further implemented form of the invention.
Figure 3 is a flow chart illustrating the function of another embodiment of the invention.
As shown in figure I, a pressure sensor 4, for the detection of the air pressure inside of the tire, and a temperature sensor 6, for the detection of temperature, are placed in vehicle tire 2. Structure and function of such sensors are generally known and are therefore not elaborated upon. The pressure sensor 4, for the detection of air pressure in the tire, does not necessarily have to be placed immediately in the interior space of the tire; it can also be placed at a valve, such that the pressure sensitive element of pressure sensor 4 detects the internal pressure of the tire. The temperature detected by the temperature sensor 6 should be little influenced by the wall of the tire, so that the temperature sensor can be placed, thermally insulated, at the rim. If the pressure sensor 4 is placed at the valve and the temperature sensor 6 is not placed at the internal wall of the tire, but at the rim, the tire itself is not affected by the sensors. It is also possible to install both sensors at the valve or at the rim.
The output signals of sensors 4 and 6 are transmitted to an evaluating unit 8.
Depending upon the structure and arrangement of the sensors, this can for example occurs: mechanically, by sliding contact, wireless, in generally known ways, including: inductively, eapaeitively, or unidirectionally by radio or bidireetionally by transponders which communicate with a sending/receiving unit 10 which edits the signals sent 1rom the assigned transponders by the sensors and supplies input to evaluating unit 8. An ambient air pressure sensor 12 and a velocity sensor 14 are connected to the inputs of the evaluating unit 8.
The evaluating unit 8 contains a generally known microprocessor 16 with a program memory 18 and a data memory 20.
An output of evaluating unit 8 is directed to monitoring or alerting unit 22 and may be for example a warning light or a display in a vehicle switchboard with . additional acoustic display if desired.
A functional example of the described unit is explained by the flow chart of a...DTD: figure 2.
:' .. The method starts in step 30, and in step 32 pressure and temperature values of : 20 a predetermined cycle of sensors are stored into memory of evaluating unit 8. The stored values are edited in step 34, for example filtered to eliminate transient fluctuations or external interferences. In step 36 the processed and read pressure values will be compensated with the processed and read temperature values for instance according to the formula Pc = p,,. x Tc/Tm wherein Pc is the temeperature compensated and measured pressure value pit, is the measured pressure value, To is a reference temperature, and Tm is the measured temperature. The temperatures are each absolute temperature values. The temporal fluctuation of the pressure values generated and compensated in step 36 is then calculated in step 38 wherein various methods may be used, including: a successive communication over n values; or only the fluctuation of each of two values measured in constant consecutive intervals. It is determined in step if the temporal fluctuation of the measured compensated pressure values determined in step 38 lies above an air pressure fluctuation threshold value of Ps. It this is not the case, the method returns to step 32. If this is the case, an alarm signal is produced in step 42.
It is not shown that in one embodiment of the method, the air pressure changed threshold ps' is not a constant predetermined value, but dependent upon the difference between a pre-stored temperature compensated pressure value, which is for instance the optimal temperature compensated tire air pressure, and the currently measured compensated pressure value Ps which is continuously calculated in the evaluating unit, becomes smaller with increasing deviation, so that the system increasingly reacts more sensitively in increasingly dangerous situations during which the air pressure increasingly drops.
The air pressure fluctuation threshold value ps is a constant, predetermined, stored value in another embodiment of the implementation of the invention, and the pressure values are not only compensated dependent upon the measured temperature in step 36, but dependent on further parameters influencing the internal pressure of the tires, like the measured ambient air pressure by the sensor 12 and/or the measured . vehicle velocity by velocity sensor 14.
The compensation occurs when according to the general formula Pc = pa x f (T. xi), whereby f (T. xj) is a function which indicates an independent value : of the conversion of the measured pressure value wherein parameter T influences the :' 20 temperature and parameters x; influence the pressure.
The explained compensation can alternatively or additionally occur for the threshold value fluctuation. .
The system and respectively the method can be modified in various respects.
For example, the time of the temporal pressure fluctuation, determined in step 40, can be extrapolated for when a predetermined low and dangerous air pressure will occur, so that the driver of a vehicle can assess how long he can still drive on a tire with an effected pressure drop. Further, the above mentioned reference air pressure, which corresponds to an optimal tire air pressure, can not only be compensated corresponding to temperature, but also other factors which influence the optimal air pressure, like the vehicle's load, the vehicle's velocity etc. Likewise a stored and improperly low air pressure, the undermining of which will generate a warning signal and exceeding of which will be calculated where s appropriate, can depend upon such parameters. It is understood that the system according to the invention includes preferably all vehicle tires.
Figure 3 depicts a flowchart that has been altered from figuec 2 and comprises another embodiment of the present invention. Tile steps 3() to 36 coincide with the same numbered steps in figure 2. In step 50, the difference between the current and a previously determined measured or compensated pressure value rip is calculated. If this is the case, the deviation Ap is then stored in step 54 together with the time of its dctennination.
The sum of the deviations I\p; which have occurred within a predetermined time interval, is determined in step 56. If it has been determined, in step 52, that Ap is less than or equal to the predetermined first threshold value pa then the system jumps immediately to step 56.
It is determined in step 58 if the generated sum in step 56 is greater than the second threshold value Ps2 If this is not the case, the system then jumps back to step 32. If this is the case, an alarm signal is then produced in step 60.
. An advantage which is achieved with the method according to figure 3 lies . therein that within each determined sum generation in step 56 and a time interval which I. is predetermined in its length, only those pressure deviations are detected which are above threshold according to step 52. Subtle pressure deviations which are for example : 20 only conditioned by fluctuations of the ambient pressure or other extreme parameters are suppressed from the start. It is understood that the threshold values of steps 52 and ..e 58, as well as the time interval of the step 56, can be adjusted to certain conditions, such as to the determined compensated pressure value, ambient temperature, vehicle velocity, vehicle load etc. Reference List 2 Tires of vehicle; 4 Pressure sensor 6 Temperature sensor; 8 Evaluating unit Sending/Receiving Unit 11 Ambient air pressure sensor 14 Velocity sensor 16 Microprocessor 18 Program memory 20 Data memory 22 Alerting or Monitoring unit
Claims (4)
- I. A method for the detection of a pressure drop in a tire, during which method air pressure and temperature within a tire are measured, the measured air pressure is converted into a temperature compensated air pressure accor-ling to the temperature, a temporal fluctuation of the temperature compensated air pressure is determined and an alerting signal is produced when the air pressure fluctuates in a predetermined way, characterized in that, the difference between a cunent and a previously determined measured or compensated air pressure value is calculated and stored together with the times of its determination; and the sum of the stored differences within a predetermined time interval is calculated and an alerting signal is produced when the sum exceeds a predetermined second threshold value.
- 2. The method according to claim 1, characterized in that, a time is determined for which the measured pressure drops below a predetermined air pressure limit and this time is displayed. a. seaIn.
- 3. A system for the detection of a pressure drop in a tire, containing: an air pressure sensor (4) for detection of an air pressure in a tire (2), a temperature sensor (6) I . for detection of a temperature in a tire, and an evaluating unit (8) which receives sensor : 20 signals of and is connected to an alerting unit (22), whereby the evaluating unit converts measured air pressure values and temperature values into temperature a e.e a e. compensated air pressure values and produces an alerting signal when the temperature . compensated air pressure fluctuates in a predetermined way, characterized in that, the evaluating unit stores the difference between a current and a previously determined measured or compensated air pressure value, together with the times of its determination; and calculates the sum of the stored differences within a predetermined time interval and produces an alerting signal when the sum exceeds a predetermined second threshold value.
- 4. A system for the detection of a press-e drop in a. tire according to claim 3, characterized in that, the evaluating unit (8) determines the time for which the measured air pressine drops beloved an acceptah]e air pressure and this time.s displayed.4. A system for the detection of a pressure drop in a tire according to claim 3, characterized in that, the evaluating unit (8) determines the time for which the measured air pressure drops below an acceptable air pressure and this time is displayed.Amendments to the claims have been filed as follows 1. A method for the detection of a pressure drop in a tire, during which method air pressure and temperature within a tire are measured, the measured air pressure is converted into a tempcratrre compensated air pressure according to the temperature, a temporal fluctuation of the temperature compensated air pressure is determined and an alerting signal is produced when the air pressure fluctuates in a predetermined way, characterized in that, the difference between a curtest and a previously determined compensated air pressure value is calculated and stored together with the time of its determination when the difference exceeds a predetermined first threshold value; and the sun of the stored differences within a predetermined time interval is calculated and an alerting signal is produced when the sum exceeds a predetermined second threshold value.2. The method according to claim 1, characterized in that, a time is determined for which the measured pressure drops below a predetermined air pressure limit and this time is displayed.3. A system for the detection of a pressure drop in a tire, containing: an air pressure sensor (4) for detection of an air pressure in a tire (2), a temperature sensor (6) for detection of a temperature in a tire, and an evaluating unit (8) which receives sensor signals and is connected to an alerting unit (22), whereby the evaluating unit converts measured air pressure values and temperature values into temperature compensated air pressure values and produces an alerting signal when the temperature compensated air pressure:fluctuates in a predetet1llined way, chaiacterizecl in that, the evaluating unit stores flee dificrence between a current and a previously determined compensated air pressure value, together with the time of its determination when the difference exceeds a predetenninecl threshold value; and calculates the sum of the stored differences within a precleten1lined time interval and produces an alerting signal when the slim exceeds a prCclLtern:]inCd second threshold value.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10144361A DE10144361B4 (en) | 2001-09-10 | 2001-09-10 | Method and system for detecting a pressure drop in a tire |
| GB0220726A GB2381635B (en) | 2001-09-10 | 2002-09-06 | Method and system for the detection of a pressure drop in a tire |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0500628D0 GB0500628D0 (en) | 2005-02-23 |
| GB2406947A true GB2406947A (en) | 2005-04-13 |
| GB2406947B GB2406947B (en) | 2005-09-21 |
Family
ID=34378997
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0500628A Expired - Fee Related GB2406947B (en) | 2001-09-10 | 2002-09-06 | Method and system for the detection of a pressure drop in a tire |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2406947B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2416400A (en) * | 2004-07-19 | 2006-01-25 | Ford Global Tech Llc | Detecting leakage from a tyre |
| WO2006117310A1 (en) * | 2005-05-04 | 2006-11-09 | Societe De Technologie Michelin | Method for monitoring the pressure and assisting in the inflation of a tire of a vehicle wheel |
| WO2011116925A1 (en) * | 2010-03-24 | 2011-09-29 | Continental Automotive France | Method and unit for the optimized transmission of measurement of paramaters of vehicle tyres |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0341226A2 (en) * | 1988-04-28 | 1989-11-08 | Schrader Automotive Inc. | On-board tire pressure indicating system performing temperature-compensated pressure measurement, and pressure measurement circuitry thereof |
| US4893110A (en) * | 1987-11-09 | 1990-01-09 | Compagnie Generale Des Establissements Michelin-Michelin & Cie | Process for detecting anomalies by use of pressure and temperature measurements in a tire-monitoring device |
| GB2311400A (en) * | 1996-03-22 | 1997-09-24 | Daimler Benz Ag | Method and apparatus for monitoring vehicle tyres |
| WO1998006078A1 (en) * | 1996-08-05 | 1998-02-12 | Semisystems, Inc. | Vehicular data collection and transmission system and method |
| US6243007B1 (en) * | 1999-12-01 | 2001-06-05 | Mclaughlin John T. | Tire condition monitoring system |
-
2002
- 2002-09-06 GB GB0500628A patent/GB2406947B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4893110A (en) * | 1987-11-09 | 1990-01-09 | Compagnie Generale Des Establissements Michelin-Michelin & Cie | Process for detecting anomalies by use of pressure and temperature measurements in a tire-monitoring device |
| EP0341226A2 (en) * | 1988-04-28 | 1989-11-08 | Schrader Automotive Inc. | On-board tire pressure indicating system performing temperature-compensated pressure measurement, and pressure measurement circuitry thereof |
| GB2311400A (en) * | 1996-03-22 | 1997-09-24 | Daimler Benz Ag | Method and apparatus for monitoring vehicle tyres |
| WO1998006078A1 (en) * | 1996-08-05 | 1998-02-12 | Semisystems, Inc. | Vehicular data collection and transmission system and method |
| US6243007B1 (en) * | 1999-12-01 | 2001-06-05 | Mclaughlin John T. | Tire condition monitoring system |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2416400A (en) * | 2004-07-19 | 2006-01-25 | Ford Global Tech Llc | Detecting leakage from a tyre |
| WO2006117310A1 (en) * | 2005-05-04 | 2006-11-09 | Societe De Technologie Michelin | Method for monitoring the pressure and assisting in the inflation of a tire of a vehicle wheel |
| JP2008540208A (en) * | 2005-05-04 | 2008-11-20 | ソシエテ ド テクノロジー ミシュラン | Method for supporting inflation by monitoring tire pressure on vehicle wheels |
| CN101184637B (en) * | 2005-05-04 | 2012-04-04 | 米其林技术公司 | Method for monitoring the pressure and assisting in the inflation of a tire of a vehicle wheel |
| WO2011116925A1 (en) * | 2010-03-24 | 2011-09-29 | Continental Automotive France | Method and unit for the optimized transmission of measurement of paramaters of vehicle tyres |
| FR2958065A1 (en) * | 2010-03-24 | 2011-09-30 | Continental Automotive France | METHOD AND OPTIMIZED TRANSMISSION UNIT FOR MEASURING PARAMETERS OF VEHICLE TIRES |
| CN102791500A (en) * | 2010-03-24 | 2012-11-21 | 法国欧陆汽车公司 | Method and unit for the optimized transmission of measurement of parameters of vehicle tyres |
| US8742915B2 (en) | 2010-03-24 | 2014-06-03 | Continental Automotive France | Method and unit for the optimized transmission of measurement of parameters of vehicle tyres |
| CN102791500B (en) * | 2010-03-24 | 2015-07-22 | 法国欧陆汽车公司 | Method and unit for the optimized transmission of measurement of parameters of vehicle tyres |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2406947B (en) | 2005-09-21 |
| GB0500628D0 (en) | 2005-02-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20070906 |