THE PATENTS ACT 1970 [39 OF 1970]
& THE PATENTS (AMENDMENT) RULES, 2006
COMPLETE SPECIFICATION
[See Section 10; rule 13]
TYRE PRESSURE MONITORING SYSTEM
HELLA INDIA AUTOMOTIVE PVT. LTD., an Indian company, of Nanospace, Baner-Pashan Link Road, Pune-411045, Maharashtra, India,
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to Tyre Pressure Monitoring System (TPMS) and more particularly, to a system for tyre pressure monitoring through periodic polling by a plurality of sensors connected to the tyres of a vehicle.
Generally vehicles have approximately 80% of rest time i.e. the vehicle in stationary mode and 20% of run time i.e. the vehicle in run mode. Since, proper air pressure in the tyre is critical to the safety of the vehicle while in motion, TPMS sensors need to be active mostly during run mode of the vehicle. The TPMS sensor is required to identify these stationary and run modes and determine the wake-up and sleep time of the vehicle to optimize life of a battery embedded in TPMS housing.
The conventional TPMS sensors are provided with a wakeup sensor for determining vehicle's motion status. These sensors detect the status of the vehicle to effectively manage the wake/sleep modes in the existing system. The sleep and wakeup is done through an external wakeup sensor which is normally an accelerometer sensor or a rolling ball sensor or a shock sensor. The TPMS sensor uses such hardware based interrupts to manage the wakeup and sleep operations. The wakeup sensor performs wake up function for all TPMS sensors connected to a vehicle after reaching a minimum speed of 1 km/h or more. After the sensors are awake, each sensor starts its pressure measurement cycle and transmits measured values to the intended receiver.
The intended receiver may be an Electronic Control Unit (ECU) in the vehicles dashboard or
a smartphone. As the vehicle comes to rest, the wakeup sensor again puts respective TPMS sensors to sleep. However, installation of the wakeup sensors increases the cost, weight and size of the TPMS.
As the TPM sensors are completely isolated from the vehicles electrical network, the TPMS cannot access the information from the vehicles network for detection of motion. It does not have access to the vehicle's battery supply. Due to continuous functioning of the TPMS sensors, the battery life of the TPMS sensors is awfully poor and replacement of the batteries causes difficulty to the drivers. Therefore, it is required that the TPMS should be designed in

such a way that it is highly optimized for current consumption and achieves a good lifetime for a given battery.
Thus, there is a need to provide a system and a method that mitigates the above mentioned drawbacks.
It is the principal object of the present invention to provide a tyre pressure monitoring system.
It is another object of the present invention to provide a system that eliminates the use of wakeup hardware sensor.
It is another object of the present invention to provide a system to manage wake up and sleep functions of the TPMS Sensors.
It is another object of the present invention to provide a system to manage wake up and sleep functions of the TPMS Sensors without hampering the Sensor battery life .
It is yet another object of the present invention to provide user defined configurations to optimize battery life.
It is yet another object of the present invention to provide a system that does time synchronization and avoids overlapping of transmission events of all the TPMS sensors.
SUMMARY OF THE INVENTION
According to an embodiment of the present invention, a tyre pressure monitoring system (TPMS) for a vehicle is provided comprising at least one TPMS sensor connected to each
tyre of the vehicle, an intended receiver compatible to send data request and perform human machine interface (HMI I/F) functions in wireless communication with each of the TPMS sensors, a Bluetooth Low Energy Chip (BLEC) to transmit and receive data request input from the intended receiver using a wireless communication, a battery to provide power source to the TPMS, and a display unit placed in the vicinity of the vehicle to display the data received by the intended receiver.
According to an embodiment of the present invention, the BLEC does periodic polling to check data request input from the intended receiver in stationary mode and run mode.

According to an embodiment of the present invention, the BLEC further comprises a Central Processing Unit, a memory, a Radio Frequency core, general input and output units, a sensor controller engine, timing circuits and a temperature monitor.
According to an embodiment of the present invention, the at least four TPMS sensors measure pressure, temperature and the battery voltage.
According to an embodiment of the present invention, the BLEC of the TPMS sensors during periodic polling receives the data request from the switched ON intended receiver.
According to an embodiment of the present invention, the BLEC on receiving data request from the intended receiver wakes up the TPMS sensors to transmit the data periodically to the intended receiver.
According to an embodiment of the present invention, the BLEC of the TPMS sensors switches OFF the TPMS system on failure to receive data request from the intended receiver during periodic polling.
According to an embodiment of the present invention, the switched OFF TPMS system maintains the data measurement and transmission functions of the TMPS sensors in sleep
mode.
According to an embodiment of the present invention, in the stationary mode advertising interval of each TPMS sensor is 40 seconds with advertising window of 3.2 seconds having 9 advertising events to exchange the data with the intended receiver.
According to an embodiment of the present invention, in the run mode the TPMS sensors measures pressure after every 16 seconds, advertise the data in every 64 seconds and
exchange the data with the intended receiver within the advertising window of 3.2 seconds having 9 advertising events.
According to an embodiment of the present invention, the TPMS sensors are synchronized with tune to avoid overlapping with each other during data transmission.
According to an embodiment of the present invention, the TPMS sensors on receiving data parameters out of range immediately starts transmitting data without waiting for its actual advertising cycle.

According to another embodiment of the present invention, a tyre pressure monitoring method for a vehicle is provided comprising connecting at least one TPMS sensor to each tyre of the vehicle, sending data request and performing human machine interface (HMI I/F) functions in wireless communication with each TPMS sensor, transmitting and receiving data request input from the intended receiver using a wireless communication, providing power source to the TPMS; displaying the data received by the intended receiver, and periodically polling to check data request input from the intended receiver in stationary mode and ran mode.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constitute a part of the description and are used to provide further understanding of the present invention. Such accompanying drawings illustrate the embodiments of the present invention that are used to describe the principles of the present invention together with the description.
Fig. 1 illustrates an overview of the TPMS according to an embodiment of the present invention;
Fig. 2 illustrates block diagram of a conventional TPMS;
Fig. 3 illustrates block diagram of TPMS according to an embodiment of the present invention;
Fig. 4 illustrates timing diagram of data measurement and transmission according to an embodiment of the present invention;
Fig. 5 illustrates timing diagram of alignment of sensors for time synchronization and overlapping avoidance according to an embodiment of the present invention; and
Fig. 6 illustrates timing diagram for alert scenarios according to an embodiment of the present invention.
The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. Each

embodiment described in this disclosure is provided merely as an example or illustration of the present invention, and should not necessarily be construed as preferred or advantageous over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. The embodiment provided herein is for the purpose of filing the complete specification.
The terms "driver'", "receiver", "intended receiver" and "user5 have been used interchangeably.
Fig. 1 illustrates an overview of the TPMS according to an embodiment of the present invention. The TPMS discloses plurality of sensors (14) connected to four tyres in a vehicle (12). Although, the present invention is described with respect to four wheeler vehicles (12), the same is not only limited to the four wheeler vehicles (12) and may be applicable in the vehicles (12) having a plurality of tyres. The information received by the TPMS sensors (14) is further communicated to a receiver (16) having a display unit (18) so that the information can be used by the receiver (16) or driver of the vehicle (12). The receiver (16) generally may be an end user having a Bluetooth Low Energy (BLE) ECU or a smart phone placed in the vicinity of the vehicle (12).
Fig. 2 illustrates block diagram of a conventional TPMS. A coin cell battery (24) is used to power a TPMS sensor (14) and a wakeup sensor (28) placed in the TPMS. The said wakeup
sensor (28) is activated when the tyre is in motion. The TPMS sensor (14) has a pressure sensor that measures air pressure in the tyre. The pressure sensor (14) is also powered by the coin cell battery (24). The air pressure measured by the pressure sensor (14) is amplified by an amplifier (26) and then fed to an analog to digital converter (ADC) (32) mounted in a BTLE (Bluetooth Low Energy) chip (30). The BTLE chip (30) has different modules like a Central Processing Unit CPU (34), a memory (36), a RF core (38), general inputs and outputs (39), a sensor controller engine (40), timing circuits (41) and a temperature monitor (42). The TPMS sensor (14) also measures all data parameters such as pressure, temperature, battery voltage and the like. The BTLE chip (30) has a transmitter/receiver to transmit and receive data from the receiver (16), i.e. a smart phone or the vehicle ECU. The wireless communication between the TPMS sensor (14) and the receiver (16) is done through wireless communication (22) using radio waves/smart Bluetooth or/and any other on air

communication protocol. The wireless communication (22) interface to be used in particular is Smart Bluetooth/Bluetooth Low Energy /Bluetooth v4.0 / IEEE 802.15.1 In addition to the foregoing description, a separate display unit (18) may be placed in the interior of the vehicle (12) to display the measured parameters on the screen which is further interfaced with the human machine interface (HMI I/F). The receiver (16) is also configured to check the TPMS values on his smart phone or similar handheld device (18) by using a mobile application. Conventionally, the TPMS constantly sends values to the mobile application through Bluetooth whenever the wakeup sensor (28) is activated due to motion of the vehicle which could be as minimum as 1km/hr and leads to quick depletion of a battery (24).
Fig, 3 illustrates block diagram of TPMS according to an embodiment of the present invention. A coin cell battery (24) is used to power a TPMS sensor (14). The present invention does not have a wake up sensor (28) as disclosed in Fig. 2. The TPMS sensor (14) comprises a pressure sensor (14) that measures air pressure in the tyre. The pressure sensor (14) is also powered by the coin cell battery (24). The air pressure measured by the pressure sensor (14) is amplified and then fed to an analog to digital converter (ADC) (32) mounted in a BTLE (Blue Tooth Low Energy) chip (30). The BTLE chip (30) has different modules like a Central Processing Unit (34), a memory (36), a Radio Frequency (RF) core (38), general inputs and outputs (39), a sensor controller engine (40), timing circuits (41) and a temperature monitor (42). The TPMS sensor (14) may also be used to measure other data parameters such as pressure, temperature, battery voltage and the like. The BTLE chip (30) has a transmitter/receiver to transmit and receive data from the receiver (16) i.e. a smart phone or the vehicle ECU. The wireless communication between the TPMS sensor (14) and the receiver (16) is done through wireless communication (22) using radio waves, smart Bluetooth or/and any other on air communication protocol.
According to an embodiment of the present invention, the wireless communication interface to be used in particular may be a Smart Bluetooth, Bluetooth Low Energy /Bluetooth v4.0 or IEEE 802.15.1. In addition to the foregoing description a separate display unit (18) may be placed in the interior of the vehicle (12) to display the measured parameters on the screen which is further interfaced with the human machine interface (HMI 1/F).
According to an embodiment of the present invention, the Bluetooth IC of TPMS sensor (14) does periodic polling to check data request inputs from the intended receiver (16). Once it receives the data request, it further wakes up the TPMS sensor (16) to transmit the data

periodically to the intended receiver (16). It continues the pressure measurement, other system functions and transmission cycle until it is receiving the data request from the receiver (16). The receiver (16) will send the data request to TPMS sensor (14) when it is powered ON in case of an ECU or when an application is run on the smartphone. As soon as the TPMS sensor (14) fails to receive data request, it concludes that there is no intended receiver (16) present to receive the transmitted data and the vehicle (12) has become stationary. This enables the TPMS sensor (14) to power off the TPMS system.
According to another embodiment of the present invention, a method to manage the wake
up/sleep functions of TPMS Sensors is disclosed. Accordingly, use of additional hardware components like wake up sensor (28) to wakeup the TPMS sensor (14) is eliminated. The TPMS of the present invention allows users to configure certain time parameters from the receiver (16) user interface UI to personalize the settings. The method has been developed keeping in mind that the standard vehicle (12) driving cycle consists of 4 hours of running mode and 20 hours of stationary mode in one day.
Thus, there are two main modes of operation for the sensor (14), viz. stationary and running, which are defined below. Depending on the mode, the profile characteristics such as advertising interval, data measurement and transmission interval time are defined.
Stationary Mode:
When the vehicle (12) is at rest, the TPMS will be in stationary mode. In this mode, all the four TPMS sensors (14) will be continuously polling for any data request from the
user/receiver (16). All other sensor functions like data measurement and transmission will remain in sleep mode during this time. In this mode, the advertising interval by each TPMS sensor (14) is 40 seconds. The advertising interval is generally the time interval between two consecutive advertising events. The advertising interval should always be optimum enough to advertise and get connected to minimize the connection latency and simultaneously not adversely affect the power consumption of the battery (24). Further, the advertising window is of 3.2 seconds and it will contain 9 advertising events within the window of 3.2 seconds. The advertising window is the time span of one advertising event where the sensor (14) would try to get connected with the intended receiver (16). The advertising window should have sufficient number of advertising events to get scanned from the smartphone device.

Time to wakeup for 4 sensors: In the worst case scenario, all the four sensors will overlap with each other while advertising and only one out of four sensors gets scanned at a time. So, in that case the time required for the sensors (14) to wake up will be
= 4 * Advertising window + 3 * Advertising interval = 4*3.2+3*40 =132.8 seconds.
This time is comparable with the previously used technology in case of ECU as a receiver (16). For instance, this time greatly reduces when a smart phone acts as the receiver (16) and is comparable to the time consumed by the previous technology, i.e., when the user comes in range of the sensor enabled vehicle (12), gets in the vehicle (12) and starts driving. In the present invention, once the sensors (14) find the intended (previously learned) receiver (16) and all of them get synchronized in due time intervals with the receiver (16), the other functions of each sensor (14) will be started. This can be termed as sensor wake up event and the sensors (14) will be in running mode.
Run Mode:
Once the vehicle (12) is about to run and the receiver (16) has started the TPMS mobile application (No need to explicitly start the TPMS receiver ECU in dashboard) the mode of TPMS operation is defined as run mode. In this mode, the sensor (14) measures data
parameters such as pressure, battery voltage and temperature and transmits these data values to the intended receiver (16). The time cycle in which the data values are measured and transmitted is given below.
Data Measurement and Transmission - Once the TPMS sensor receives a data request, each sensor (14) will start their pressure measurement cycles. In this activity, all the parameters like air pressure, temperature and battery voltage will be measured by respective sensor modules. During this cycle, each sensor (14) will measure pressure after every 16 seconds and transmit the data of pressure, battery voltage and temperature after every 64 seconds as shown in Fig 4. So the receiver (16) will be able to get the data from all the four sensors (14) within 64 seconds. The receiver (16) should send periodic data request to the sensors (14) in order to continue the pressure measurement and transmission cycles from the sensors (14) .If the receiver (16) fails to send the data request for four consecutive advertising events then the sensor (14) concludes that no receiver (16) is present and goes to sleep MODE. In RUN

mode each sensor (14) will advertise after every 64 seconds and exchanges the relevant data during the connection event which happens in the prescribed advertising window of 3.2 seconds. Further, the advertising window in RUN Mode 9 has advertising events.
vicinity of the vehicle (12) and starts the TPMS application in the smartphone. The user then goes further to unlock the vehicle (12) and start the same. (No need to start explicitly if the TPMS receiver is in dashboard). Once the application or the receiver (16) ECU's UI is started, it starts sending data requests to all the sensors (14). Once the sensors (14) receive data request from the receiver (16), it will start its pressure measurement cycle and transmit the measured pressure at every 64 seconds. As per the design, the receiver (16) should be able to receive data from all the four sensors (14) within 64 seconds. In order to achieve this, the sensors (14) should not overlap with each other and they must be synchronized with the time.
Fig. 5 illustrates timing diagram of alignment of sensors for time synchronization and overlapping avoidance wherein all the sensors (14) namely Sensor 0 (14a), Sensor 1 (14b), Sensor 2 (14c) and Sensor 3 (14d) are advertising with an interval of 40 seconds for a window of 3.2 seconds. Any sensor (14) receiving the first data request from the intended receiver (16) will be the Sensor 0 (14a) and it will be considered as reference for aligning the other sensors (14b, 14c, 14d). Suppose Sensor 0 (14a) was scanned at time t = tO seconds. The receiver (16) application will note down this time and align the next three sensors, Sensor 1 (14b), Sensor 2 (14c) and Sensor 3 (14c) at time t0+16, t0+32 and tO+48 seconds respectively. So after every 16 seconds one sensor (14a, 14b, 14c, 14d) will be advertising with the data and after the end of 64 seconds (16*4) the receiver (16) will get the data from all the four sensors.
The time synchronization parameter used for the synchronization of sensors (14) is given as:
tsp = 64n + (16k - (tk - tO))
where,
tsp is the time in seconds after which the sensor should start their advertising cycle if they are found at time t = tk seconds.
k is the sensor no. which is in the order in which it got scanned. It can have value from 1,2,3.

tk is the time at which kth sensor is found/scanned. n = 0 if the sensor got found before 16k n - 1 if the sensor got found after 16k
Alert scenarios:
Fig. 6 illustrates timing diagram for alert scenarios according to an embodiment of the present invention wherein the sensor (14) measures pressure in an interval of 16 seconds but transmits at the interval of 64 seconds. This means that the data is transmitted only once out of four pressure measurement cycles. In the remaining three events, the data is measured and checked whether the data parameters are in acceptable range. If any of the data parameters are out of range which is an alert mode scenario for a sensor (14), then it shall start transmitting immediately without waiting for its actual advertising cycle. Here, the time interval will be 16 seconds for measuring and transmission as well. This increased rate of data transmission for this sensor (14) will be achieved by transmitting the data only through additional advertising events and will stop only when the data parameters comes to normal limit values. The data request of 64 seconds from the receiver would continue as per the norma! operation cycle. And similarly sleep function of the sensor as defined in data measurement and transmission function in run mode.
With a 300 mah (mili-amp-hours) coin cell battery (24), the estimated life of TPMS sensor (14) is about 5 years and with 550 mah coin cell battery (24), the estimated life of TPMS sensor (14) is about minimum of 8 to 9 years which is comparable with the present existing
technology. The battery life thus directly depends on profile time parameters and is subject to change to achieve greater battery life or user requirement. In this way, the present invention achieves a good battery life by reducing the material cost, TPMS sensor size and weight.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended
to be comprehended within the meaning and range of equivalents of the disclosed
embodiments.

We claim:
1. A tyre pressure monitoring system (TPMS) for a vehicle (12) comprising:
at least one TPMS sensor (14a, 14b, 14c, 14d) connected to each tyre of the vehicle (12),
an intended receiver (16) compatible to send data request and perform human machine interface (HMI I/F) functions in wireless communication (22) with each of the TPMS sensors (14a, 14b, 14c, 14d),
- a Bluetooth Low Energy Chip (BLEC) (30) to transmit and receive data request input from the intended receiver (16) using a wireless communication (22);
- a battery (24) to provide power source to the TPMS, and
a display unit (18) placed in the vicinity of the vehicle (12) to display the data received by the intended receiver (16),
wherein the BLEC (30) does periodic polling to check data request input from the intended receiver (16) in stationary mode and run mode.
2. The TPMS as claimed in claim 1, wherein the BLEC (30) further comprises a Central Processing Unit (34), a memory (36), a Radio Frequency core (38), general input and output units (39), a sensor controller engine (40), timing circuits (41) and a temperature monitor (42).
3. The TPMS as claimed in claim 1, wherein the at least four TPMS sensors (14) measures pressure, temperature and the battery voltage.
4. The TPMS as claimed in claim 1, wherein the BLEC (30) of the TPMS sensors (14) during periodic polling receives the data request from the switched ON intended receiver (16).
5. The TPMS as claimed in claim 4, wherein the BLEC (30) on receiving data request from the intended receiver (16) wakes up the TPMS sensors (14) to transmit the data periodically to the intended receiver (16).
6. The TPMS as claimed in claim I, wherein the BLEC (30) of the TPMS sensors (14) switches OFF the TPMS system on failure to receive data request from the intended receiver (14) during periodic polling.

I. The TPMS as claimed in claim 6, wherein the switched OFF TPMS system maintain
the data measurement and transmission functions of the TMPS sensors (14) in sleep
mode.
8. The TPMS as claimed in claim 1, wherein in the stationary mode the advertising interval by each TPMS sensor (14) is 40 seconds with advertising window of 3.2 seconds having 9 advertising events to exchange the data with the intended receiver (16).
9. The TPMS as claimed in claim 1, wherein in the run mode the TPMS sensors (14) measures pressure after every 16 seconds, advertise the data in every 64 seconds and exchange the data with the intended receiver (16) within the advertising window of 3.2 seconds having 9 advertising events.
10. The TPMS as claimed in claim 1, wherein the TPMS sensors (14) are synchronized with time to avoid overlapping with each other during data transmission
11. The TPMS as claimed in claim1, wherein the TPMS sensors(14) on receiving data parameters out of range immediately starts transmitting data without waiting for its actual advertising cycle.
12. A tyre pressure monitoring method (TPMS) for a vehicle (12) comprising:
connecting at least one TPMS sensor (14a, 14b, 14c, 14d) to each tyre of the vehicle (12),
- sending data request and performing human machine interface (HM1 1/F) functions in wireless communication (22) with each TPMS sensor (14a, 14b, 14c, 14d),
- transmitting and receiving data request input from the intended receiver (16) using a wireless communication (22);
- providing power source to the TPMS;
- displaying the data received by the intended receiver (16), and
- periodically polling to check data request input from the intended receiver (16) in stationary mode and run mode.