Improved tyre pressure refilling (TPRS) control system for industrial vehicles

Abstract

The present invention relates to a control system (9) for controlling the automatic tyre pressure refilling in a vehicle. The system (9) includes various sensors (6, 12, 13, 14) distributed at corresponding points of its pneumatic and electrical circuit, and a controller (10) to receive outputs from the sensors and provide indicative signals in order to signal working or operative conditions, of the system, to users or observers of said vehicle. The system further comprises a controller. The sensors include a sensor (6) for detecting exhaust pulses from the pressure multiplier (3), an exhaust pressure sensor (14), a system input pressure sensor (12) and a system output pressure sensor (13). The system (9) also has an electrical connection (8) to activate a light in order to indicate different operative / abnormal conditions of the system (9).

Description

[0001]

[0002] Enhanced Tire Pressure Monitoring System (TPRS) for Commercial Vehicles

[0003] Technical sector

[0004] The present invention relates to the automotive technical sector. More specifically, it relates to automatic tire inflation or filling systems and, in particular, to the control component of such systems.

[0005] Background of the invention

[0006] The importance of tire pressure in road vehicles is well known, both for the safety of users and for the proper functioning of vehicle components, thus saving on repairs and maintenance costs. Tire pressure influences several aspects of a vehicle's performance, including rolling resistance, fuel consumption and associated emissions, braking distance, and overall vehicle stability. Repair, maintenance, or simply changing tires is one of the most common reasons for forced downtime for vehicle users. This downtime is inconvenient for any driver and translates into a significant decrease in performance, productivity, and revenue when referring specifically to commercial vehicles.Furthermore, the aforementioned factors, as already mentioned, are very important in relation to the safety and smooth operation of the vehicle. Tires with insufficient air pressure will wear more quickly and may even burst during a route, which can lead to life-threatening situations for all road users, not just the drivers of the vehicles in question. Likewise, if tire pressure varies unevenly over time, they will also wear at different rates.

[0007] Therefore, proper tire pressure monitoring, anticipating major breakdowns or damage, is a proactive measure with clear effects both economically and in terms of road safety. Savings are achieved in tire maintenance and change frequency, as well as fuel consumption, which also results in lower CO2 emissions and lower variable costs.

[0008] In this regard, road safety authorities and car manufacturers are seeking solutions and improvements, which translate, for example, into systems known as TPMS (Tire Pressure Monitoring System) and TPRS (Tire Pressure Filling System). As their names indicate, the former simply monitors tire pressure, while the latter goes a step further and automatically inflates tires when the air pressure inside them falls below a certain level. The system constantly monitors the pressure in all tires, and when it drops, the system adds air. This input comes from the air tank used, for example, for the vehicle's air suspension and brake system. Therefore, a system is needed that monitors the various pressure values ​​at various points on the circuit and prioritizes air supplies according to these values.In general, the system tops up tire pressure if any leaks occur, thus maintaining a constant inflation pressure set initially.

[0009] More specifically, among the components included in a TPRS system for European trailers and semi-trailers are a pressure multiplier or booster designed to raise the air pressure in the vehicle's compressed air system to the nominal tire inflation pressure, an output pressure regulator, and an overflow or pneumatic circuit protection valve (in most cases, this overflow valve is included in the vehicle's system). The pressure at each of these points, the actions to be taken on the components according to the detected values, and the indicative or informative signals provided to users must all be appropriately monitored and controlled.In this regard, some of the aspects addressed by the aforementioned system and its control methods include tire inflation while the vehicle is moving and also when stopped, and operating indicator elements with different lighting codes.

[0010] Although the system described above adequately performs its function, a TPRS control system with improved capabilities in terms of signaling the operation and / or possible deficiencies of the same for users of this type of vehicles would be desirable. In this regard, the present invention provides improvements in the control section of a TPRS in terms of communicating signals useful for monitoring the status of said TPRS by users and persons outside the vehicle. Furthermore, said improvements meet the requirements established by United Nations Regulation 141 relating to the approval of vehicles with respect to their tire pressure monitoring systems.

[0011] Explanation of the invention

[0012] For the aforementioned purpose, an automatic tire pressure control system for a vehicle is provided. This type of control system typically essentially comprises an overflow or protection valve to ensure priority air supply to essential vehicle components, a pressure multiplier or booster, an output pressure regulator, and an exhaust pulse sensor connected to the pressure multiplier. The overflow valve, as previously stated, is usually included in the vehicle's installation, although, for illustrative purposes (due to its functional connection to the tire pressure control system), the version in which it is included in the control system has been chosen representatively; as can be seen from the subsequent description, this does not affect the operation of the remaining components. The system also comprises a controller.The aforementioned exhaust pulse sensor can be connected to an exhaust output of the multiplier and, in this way, can detect the pulses that appear at this output; these detected pulses will indicate that tire pressure is being topped up. Furthermore, the exhaust pulse sensor can also be connected to the controller to notify it of the appearance of exhaust pulses. The controller, in turn, will be connected to a CAN bus of the vehicle in question, so that, via this bus, it can communicate an "Insufficient pressure value" message if the exhaust pulse sensor detects precisely these pulses at the exhaust output of the amplifier or multiplier.

[0013] According to a further feature of the invention, the exhaust pulse sensor connected to the pressure multiplier of the control system may be or comprise a flow sensor and this may be, specifically, of the turbine type, operating by Hall effect, or of the turbine and dynamo type.

[0014] According to another feature of the control system of the invention, the exhaust pulse sensor connected to the exhaust outlet of the pressure multiplier may be or may comprise an exhaust pressure sensor. This is done so that said sensor can detect excess pressures at the exhaust outlet.

[0015] In relation to this last technical characteristic, the exhaust pressure sensor may be or comprise, more specifically, a pressure transducer or a pressure switch type pressure sensor.

[0016] According to another feature of the invention, the controller may comprise or be, specifically, an Electronic Control Unit (ECU) of those commonly used in wheeled vehicles.

[0017] According to a further feature of the system of the invention, the latter may include an inlet pressure sensor and an outlet pressure sensor; in some embodiments, it may simply include one of them. The inlet pressure sensor is arranged or adapted to detect the pressure at the inlet of the automatic filling control system; the outlet pressure sensor is arranged or adapted to detect the pressure at the outlet of said system, i.e., the pressure that each corresponding tire will have.

[0018] According to a further feature of the invention, the aforementioned inlet pressure sensor is arranged, in a specific embodiment, right at the inlet of the overflow valve.

[0019] Finally, another feature of the system of the invention relates to the fact that the output pressure sensor adapted to capture the pressure intended for filling the tires will be specifically connected to the output of the pressure regulator of the system.

[0020] Brief description of the drawings

[0021] To complement the description, a series of figures are attached that illustrate the control system of the present invention:

[0022] Figure 1 shows a diagram of a tire pressure control system for a vehicle of the type commonly used.

[0023] Figure 2 shows a schematic of a vehicle tire pressure refill control system according to an embodiment of the present invention.

[0024] Figure 3 shows a schematic of a vehicle tire pressure refill control system according to another embodiment of the present invention.

[0025] Detailed description of the invention

[0026] Embodiments of the invention illustrated in the figures listed above will now be described in detail.

[0027] To begin and to situate the specific scope of application, a tire pressure refill control system, TPRS, of a vehicle according to the prior art will first be described with reference to Figure 1. Both in this diagram and in subsequent ones, which refer to refill control systems (9) according to the present invention, the parts of the systems that are relevant to explain the operation of the system (9) disclosed here have been illustrated, omitting other components that are not relevant to said operation or simply representing them schematically, such as, for example, the pneumatic installation (1) of the vehicle or the connection to the tires (5) in the various figures.

[0028] In current TPRS systems (such as the one in Figure 1), the air for inflating the tires (5) usually comes from the vehicle's compressed air installation (1), which is also used for other purposes such as a possible air suspension system and the brake system. The first element that this air encounters is an overflow valve (2) that performs a protective function and that will let air through when it detects that the pressure coming from the installation (1) is sufficient to supply the aforementioned systems (fed with compressed air) and that have priority over said refilling system. After the valve (2), we find a pressure amplifier or multiplier (3) that raises the pressure at its inlet (3a) to a suitable value, at its outlet (3b), for inflating the tires (5).(The overflow valve (2) has been represented within the control system (9) to facilitate the explanation of its function with respect to the rest of the components, although, in general, it will be physically included in the vehicle installation).

[0029] The control provided by this system (9) is materialized in the regulator (4). This pressure regulator (4) will allow the passage of air from the multiplier (3) to the outlet connection (5) towards the tires when the pressure in said connection (5) decreases below the value preset in the regulator (4), thus refilling the tire pressure. When the regulator (4) is opened, the multiplier (3) will start operating, a standard device with pistons and reciprocating movement where an air escape pulse is produced through its exhaust port (3c) with each alternation of the pistons.

[0030] One of the ways of detecting that said multiplier (3) is in operation is by monitoring its exhaust pulse output (3c), which are produced in the air compression cycles for the amplification of its pressure. Therefore, an exhaust pulse sensor (6) is provided which, as will be seen later, can take the form of various devices. This exhaust pulse sensor (6) basically generates an electrical signal - that is, it acts as a flow rate transducer to voltage or current - which can be used to power a warning light connected to the connection (8). In relation to this last component, it should be noted that the numerical references used and which are the same represent equivalent elements, parts or components or which have an equivalent function in the various figures.

[0031] This warning light therefore indicates that the pressure in one of the tires (5) has dropped below a predetermined threshold and that the pressure refill control system has been activated. The air that generated the exhaust pulses that activated the pulse sensor (6) is expelled through the exhaust outlet (7). On the other hand, the multiplied or amplified pressure is obtained at the outlet (3b) of the multiplier and is passed through the regulator (4) for its final supply to the tires (5), as explained above.

[0032] As an improvement to this control system and at the same time fulfilling the requirements of regulation 141 mentioned in the background section, the present inventors propose a tire filling control system (9) which is shown in figure 2 in the form of one of its embodiments. It is about unifying or centralizing the control of the entire system (9) under a single unit or module (the controller (10)) that interprets, orders, processes and prioritizes the signals received and emitted by it.

[0033] An additional network of sensors (12, 13, 14; figures 2 and 3) is established that capture values ​​at respective points of the pneumatic circuit and the electrical circuit that form part of the system (9).

[0034] The Electronic Control Unit or controller (10) will also be connected to a CAN bus of the vehicle. Likewise, the controller (10) (or the ECU in one of its embodiments) will be coupled to the connection (8). Thus, for example, the controller (10) can receive, at one of its inputs, the output of the inlet pressure sensor (12) and determine that, when said output of the sensor (12) is below a preset minimum inlet pressure limit, there is not enough pressure in the circuit for the system (9), whereby, under certain conditions, it can output an indicative signal. The same can be said of the outlet pressure sensor (13), or of the sensors (6, 14), whose interaction with the controller (10) will be detailed below.

[0035] Specifically, the controller (10) is arranged to output two indicative signals based on its inputs received from the sensors (6, 12, 13, 14):

[0036] - “Insufficient pressure value”, when pressure refilling is being carried out for less than 8 minutes; this pressure refill coincides with the operation of the multiplier (3) and can be detected from the air exhaust pulses produced at its exhaust port with any of the sensors (6, 14);

[0037] - “System failure”, when more than 8 minutes have passed since the start of filling and it has not stopped, when insufficient pressure is detected in any of the inlet or outlet sensors, or when a disconnection of any of the sensor cables (6, 12, 13, 14) with the controller or ECU (10) is detected.

[0038] In all of the above-mentioned cases, the ECU (10), which is electrically supplied via the CAN bus (11), would receive the signals from the sensor being used, interpret (using a program) which of the specific situations those received signals correspond to and send the corresponding message via the CAN bus (11). At the same time, the ECU (10) would supply power to the electrical connection (8) to activate the exterior warning light of the semi-trailer with an intermittent operating sequence, in the case of the message “Insufficient pressure value”, or fixed, in the case of the message “System fault”, in accordance with the established regulation.

[0039] The message “Insufficient pressure value”, together with the activation of the corresponding light, is not generated as soon as a single air escape pulse is detected (to avoid false warnings of starting the filling due to the isolated appearance of these pulses) but will be issued when a succession of these pulses is detected in a sufficient number, which can be done by programming a minimum pulse frequency from which to activate the warning.

[0040] On the contrary, when there is no anomaly, the ECU or controller (10) will constantly send a "All OK" type message to the CAN bus (11).

[0041] The exhaust pulse sensor (6) shown in Figure 2 may be, for example, a Hall effect turbine flow sensor or a turbine and dynamo flow sensor; in another embodiment, the sensor (6) may be or comprise a pressure sensor (14) shown in Figure 3. The output of this sensor (6) may be used by the controller (10) to detect that the multiplier (3) is operating and that, therefore, the system (9) is refilling the tires (5), whereby an indicative signal communicating this fact (detailed above) may be output.

[0042] The control system (9) of the present invention is designed with industrial vehicles in mind - especially those of the trailer and semi-trailer type -, which constitute the usual and reasonable field of application at present, but can be applied to any wheeled vehicle in which monitoring and subsequent automated inflation of the corresponding tires is required.

[0043] List of references

[0044] 1 Vehicle pneumatic installation

[0045] 2 Overflow valve

[0046] 3 Pressure multiplier

[0047] 3a Pressure booster inlet 3b Pressure booster outlet

[0048] 3c Pressure multiplier exhaust

[0049] 4 Pressure regulator

[0050] 5 Tires 6 Exhaust pulse sensor

[0051] 7 Final escape exit

[0052] 8 Electrical connection

[0053] 9 Tire pressure filling system

[0054] 10 Controller 11 CAN Bus

[0055] 12 Inlet pressure sensor

[0056] 13 Outlet pressure sensor

[0057] 14 Exhaust pressure sensor

Claims

CLAIMS 1. System (9) for controlling the automatic refilling of the tire pressure of a vehicle, of the type comprising a pressure multiplier (3), an output pressure regulator (4), an exhaust pulse sensor (6) and a controller (10), the exhaust pulse sensor (6) being connected to an exhaust output (3c) of the multiplier (3) to capture the pulses at said output (3c), pulses that are generated when the multiplier (3) is refilling the tire pressure, and said exhaust pulse sensor (6) being further connected to the controller (10), which is also connected to a CAN bus (11) of the vehicle and is arranged to communicate, through said bus (11), an “Insufficient pressure value” message when the sensor (6) detects exhaust pulses at the output (3c).

2. Control system (9) according to the preceding claim, wherein the exhaust pulse sensor (6) comprises a flow rate sensor (6).

3. Control system (9) according to the preceding claim, wherein the flow or flow sensor (6) comprises at least one of a Hall effect turbine flow sensor and a dynamo turbine flow sensor.

4. Control system (9) according to claim 1, wherein the exhaust pulse sensor (6) comprises an exhaust pressure sensor (14) for detecting an overpressure at the exhaust outlet (3c).

5. Control system (9) according to the preceding claim, wherein the exhaust pressure sensor (14) comprises at least one of a pressure transducer and a pressure switch type pressure sensor.

6. Control system (9) according to any of the preceding claims, wherein the controller (10) comprises an Electronic Control Unit, ECU.

7. Control system (9) according to any of the preceding claims, further comprising an inlet pressure sensor (12) arranged to detect the pressure at the inlet of the automatic refill control system (9) and / or an outlet pressure sensor (13) arranged to detect the pressure at the outlet of said system (9).

8. Control system (9) according to the preceding claim, wherein the inlet pressure sensor (12) is arranged to detect the pressure at the inlet of the overflow valve (2).

9. Control system (9) according to any one of claims 7 to 8, wherein the outlet pressure sensor (13) is arranged to detect the pressure at the outlet of the pressure regulator (4).

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