Vehicle braking assembly

Abstract

The assembly comprises a body wherein there are defined a chamber, a supply valve adapted to connect the chamber to a pressure source or to the atmosphere, and a vent valve adapted to allow or prevent the connection of the chamber to the atmosphere. The valves are provided with control solenoids to which respective electronic switches are coupled. The assembly also comprises electronic control devices adapted to provide, as a function of the values of at least one input signal, logic control signals to the electronic switches so as to control, through the valves, the value of the pressure in the chamber. The control means comprise two processing and control devices independent of one another, both receiving the input signal and designed to execute strategies for controlling the pressure in the chamber, equivalent to one another.

Claims

1. An assembly comprising: a supply valve configured to be disposed between a chamber and a pressure source; a discharge valve disposed between the chamber and an external atmosphere; a first control unit coupled with the supply valve by a first switch and with the discharge valve by a second switch, the first control unit configured to receive input signals indicative of a vehicle weight and a pressure in the chamber, the first control unit configured to generate first output signals based on the input signals to the first switch and the second switch to control the supply valve and the discharge valve; and a second control unit coupled with the discharge valve by a third switch and with the supply valve by a fourth switch, the second control unit configured to receive the input signals indicative of vehicle weight and the pressure in the chamber, the second control unit configured to generate second output signals based on the input signals to the third switch and the fourth switch to control the supply valve and the discharge valve.

2. The assembly of claim 1, wherein the supply valve and the discharge valve are configured to increase the pressure in the chamber responsive to the first output signals from the first control unit conflicting with the second output signals from the second control unit.

3. The assembly of claim 1, wherein the supply valve and the discharge valve are configured to decrease the pressure in the chamber responsive to the first output signals from the first control unit conflicting with the second output signals from the second control unit.

4. The assembly of claim 1, wherein the supply valve and the discharge valve are configured to increase the pressure in the chamber responsive to the first output signals from the first control unit matching the second output signals from the second control unit.

5. The assembly of claim 1, wherein the supply valve and the discharge valve are configured to decrease the pressure in the chamber responsive to the first output signals from the first control unit matching the second output signals from the second control unit.

6. The assembly of claim 1, wherein the supply valve and the discharge valve are coupled with each other in a series.

7. The assembly of claim 6, wherein the supply valve and the discharge valve are configured to be coupled with the chamber with the chamber between the supply valve and the discharge valve.

8. An assembly comprising: a first control unit coupled with a supply valve by a first switch and with a discharge valve by a second switch, the first control unit configured to receive input signals indicative of a vehicle weight and a pressure in a chamber, the first control unit configured to generate first output signals based on the input signals to the first switch and the second switch to control the supply valve and the discharge valve to control a pressure inside the chamber; a second control unit coupled with the discharge valve by a third switch and with the supply valve by a fourth switch, the second control unit configured to receive the input signals and to generate second output signals based on the input signals to the third switch and the fourth switch to control the supply valve and the discharge valve, wherein the first control unit and the second control unit are configured to output the first output signals and the second output signals such that the supply valve and the discharge valve open or close based on whether the first output signals from the first control unit match or conflict with the second output signals from the second control unit; and a monitoring device configured to detect an operating anomaly in the first output signals or the second output signals, the monitoring device configured to disable one or both of the first control unit and the second control unit in response to detecting an operating anomaly.

9. The assembly of claim 8, wherein the first control unit and the second control unit are configured to control the supply valve and the discharge valve to increase a pressure in the chamber responsive to the first output signals from the first control unit conflicting with the second output signals from the second control unit.

10. The assembly of claim 8, wherein the first control unit and the second control unit are configured to control the supply valve and the discharge valve to decrease a pressure in the chamber responsive to the first output signals from the first control unit conflicting with the second output signals from the second control unit.

11. The assembly of claim 8, wherein the first control unit and the second control unit are configured to control the supply valve and the discharge valve to increase a pressure in the chamber responsive to the first output signals from the first control unit matching the second output signals from the second control unit.

12. The assembly of claim 8, wherein the first control unit and the second control unit are configured to control the supply valve and the discharge valve to decrease a pressure in the chamber responsive to the first output signals from the first control unit matching the second output signals from the second control unit.

13. An assembly comprising: a supply valve and a discharge valve coupled in series with each other between a pressure source and an external atmosphere, the supply valve and the discharge valve configured to be coupled with a chamber that is pressurized by the pressure source; a first control unit coupled with the supply valve by a first switch and with the discharge valve by a second switch, the first control unit configured to receive an input signal indicative of a vehicle weight and to output first signals based on the input signal to the first switch and the second switch to control the supply valve and the discharge valve; and a second control unit coupled with the discharge valve by a third switch and with the supply valve by a fourth switch, the second control unit configured to receive the input signals indicative of vehicle weight and a pressure in the chamber, the second control unit configured generate second output signals based on the input signals to the third switch and the fourth switch to control the supply valve and the discharge valve.

14. The assembly of claim 13, wherein the supply valve and the discharge valve are configured to increase the pressure in the chamber responsive to the first signals from the first control unit conflicting with the second signals from the second control unit.

15. The assembly of claim 13, wherein the supply valve and the discharge valve are configured to decrease the pressure in the chamber responsive to the first signals from the first control unit conflicting with the second signals from the second control unit.

16. The assembly of claim 13, wherein the supply valve and the discharge valve are configured to increase the pressure in the chamber responsive to the first signals from the first control unit matching the second signals from the second control unit.

17. The assembly of claim 13, wherein the supply valve and the discharge valve are configured to decrease the pressure in the chamber responsive to the first signals from the first control unit matching the second signals from the second control unit.

18. The assembly of claim 13, wherein the supply valve and the discharge valve are coupled with each other and with the chamber with the chamber disposed between the supply valve and the discharge valve.

19. The assembly of claim 13, wherein the supply valve is a solenoid valve.

20. The assembly of claim 19, wherein the discharge valve is another solenoid valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The inventive subject matter may be understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

(2) FIG. 1, described above, is a diagram of a braking system for vehicles;

(3) FIG. 2, also described above, shows a characteristic of a valve for controlling the pressure proportionally to the load;

(4) FIGS. 3 to 5 show three different embodiments of a pneumatic part of an electro-pneumatic braking assembly according to one embodiment of the inventive subject matter;

(5) FIG. 6 is a block diagram of a control system for an electro-pneumatic assembly; and

(6) FIGS. 7 to 12 are circuit diagrams, partially in block form, showing various embodiments of a control system for an electro-pneumatic assembly according to one embodiment of the inventive subject matter.

DETAILED DESCRIPTION

(7) FIG. 7 illustrates one example of a brake control system. This control system can control operation of an electro-pneumatic assembly to execute a pneumatic function on the basis of which a value of pneumatic pressure equal to or greater than a predetermined target, for example according to the characteristic shown in FIG. 2, is produced in the volume or chamber 11 of the assembly according to FIG. 3.

(8) The control system includes two electronic processing and control units 16 and 116, constructed for example in the form of microprocessor or microcontroller units, independent of one another. These units 16, 116 are made, for example, in the form of physical devices which differ from one another, and are designed to execute control strategies which are equivalent to one another, although they are implemented using corresponding software packages which are independent of, and generally different from, one another.

(9) The same input signals L, P and II as those defined above are supplied to the units 16 and 116, together with respective data PP and PP′ representing the values of parameters of the respective algorithms implemented in them. The units 16 and 116 also supply respective output signals OO and OO′.

(10) The control unit 16 is designed to drive, through respective bias circuits 17 and 18, the electronic switches 19 and 20 which are essentially connected in series with the respective energizing solenoids 12a and 13a of the solenoid valves 12 and 13. In turn, the electronic unit 116 has two outputs for driving, through bias circuits 117 and 118, corresponding electronic switches 119 and 120, connected, respectively, in parallel with the switches 19 and 20, between a ground reference (e.g., the earth GND or a vehicle chassis) and the energizing solenoids 12a and 13a.

(11) In the diagram according to FIG. 7, the electronic switches 19, 20, 119 and 120 are coupled to one another so as to form together an enabling logic circuit designed to drive the solenoids 12a and 13a in such a way that:

(12) when the logic control signals sent to the switches by the control units 16 and 116 are in agreement with one another, the energizing of the solenoids 12a and 13a of the solenoid valves 12 and 13 enables the pressure in the volume or chamber 11 to be controlled in accordance with Table 1 above, in such a way that the pressure in this volume or chamber 11 conforms (for example) to the characteristic shown in FIG. 2; and

(13) conversely, when the logic control signals sent by the units 16 and 116 towards the associated switches 19, 20 and 119, 120 conflict with one another, the logic control signals that are executed are those supplied by the unit 16 or 116 which tends to produce the greater pressure in said volume or chamber 11.

(14) The solenoid 12a (13a) is energized according to a logical OR function of the states of the switches 19 and 119 (20 and 120). With reference to Table 1, a conflict between the signals can occur if one of the two units 16 and 116, using the associated electronic switches, tends to set the condition of pressure decrease in the chamber or volume 11, while the other unit 116 or 16 tends to set the condition of pressure maintenance. As a result of the OR connection between the switches 19 and 119 and between the switches 20 and 120 respectively, the condition of pressure maintenance will prevail. For example, the pressure will not increase or decrease (e.g., by more than a threshold amount, such as 10%).

(15) Similarly, when one of the control units tends to set the condition of pressure increase while the other control unit tends to set the condition of maintenance, then, again as a result of the OR connection between the switches 16 and 119 and between the switches 20 and 120 respectively, the condition of pressure increase will prevail. For example, the pressure will increase (e.g., by at least a threshold amount, such as 10%). Additionally, the condition of pressure increase will also prevail over the condition of pressure decrease. For example, if one signal indicates a pressure increase while another signal indicates a pressure decrease, the pressure increase will occur.

(16) Consequently, the system according to FIG. 7 can be used to execute a pneumatic function adapted to produce, in the volume or chamber 11 of FIG. 3, a value of pressure equal to or greater than a predetermined target value.

(17) FIG. 8 shows the architecture of a control system for an electro-pneumatic assembly. The diagram of FIG. 8 differs from that of FIG. 7 in that the electronic switches 19 and 119 associated with the solenoids 12a of the solenoid valve 12 of FIG. 4 are connected in series with one another, between this solenoid 12a and the ground reference.

(18) The valve arrangement according to FIG. 4 and the associated control system according to FIG. 8 are such that, when the logic control signals supplied by the control units 16 and 116 conflict with one another, the logic control signals that are executed are those supplied by the unit 16 or 116 which tends to produce the lower pressure in the volume or chamber 11 (of FIG. 4). This is due to the fact that the solenoid valve arrangement according to FIG. 4 corresponds to Table 2 shown above, and is also due to the logical AND connection of switches 19 and 119 and the logical OR connection of switches 20 and 120.

(19) Thus, with reference to Table 2, it can easily be seen that, if one control unit 16 or 116 tends to set the condition of pressure decrease in the chamber or volume 11 while the other control unit 116 or 16 tends to set the condition of pressure maintenance, then, as a result of the AND connection between the switches 19 and 119, the condition of pressure decrease will prevail. Similarly, when one of the two units 16 and 116 tends to set the condition of pressure increase while the other unit 116 or 16 tends to set the condition of maintenance, then, as a result of the logical OR connection between the switches 20 and 120 and the logical AND connection between the switches 19 and 119, the condition of pressure maintenance will prevail. Finally, the condition of pressure maintenance, commanded by one of the two units, prevails over the condition of pressure increase commanded by the other unit. Consequently, a pneumatic function is executed which is adapted to produce a pressure equal to or less than a predetermined target value in the volume or chamber 11.

(20) The electro-pneumatic assembly can be used to obtain a pneumatic pressure equal to or greater than a predetermined target pressure in the volume or chamber 11. In the diagram according to FIG. 9, both the switches 19 and 119 associated with the solenoid 12a and the switches 20 and 120 associated with the solenoid 13a are coupled to one another according to a logical AND configuration.

(21) The control system shown in FIG. 10 may differ from the system according to FIG. 9 in that the switches 19 and 119 are coupled to one another according to a logical OR configuration.

(22) An electro-pneumatic assembly of this type can be used to execute a pneumatic function adapted to produce a value of pressure equal to or greater than a predetermined target value in the volume or chamber 11 of FIG. 3.

(23) FIG. 11 shows a control system for executing a pneumatic function adapted to produce a value of pressure according to a predetermined transfer function, according to the characteristic shown in FIG. 2 for example, using a solenoid valve part which may conform to any one of FIG. 3, FIG. 4, and FIG. 5. The control system according to FIG. 11 comprises, like the systems described above, two microprocessor or microcontroller control units, indicated by 16 and 116, which receive the signals L, P, II and PP (PP′) described above. The unit 16 is designed to supply at its output two logical signals X1, X2, for controlling, respectively, the solenoids 12 and 13a of the solenoid valves 12 and 13. Similarly, the control unit 116 is designed to supply at its output two logic control signals X11, X12, for controlling the solenoids 12 and 13a.

(24) A further microprocessor or microcontroller control unit 1016 based on programmable logics such as FPGA logics also is provided. This unit 1016 receives, as input, the same signals as those arriving at the units 16 and 116, to which the control unit 1016 is connected by respective two-way communication lines 23 and 123.

(25) By executing closed-loop control algorithms such as PID algorithms, “fuzzy” algorithms, or algorithms of the on-off type with hysteresis, otherwise known as bang-bang control algorithms, the control units 16 and 116 can produce, for example, the characteristic according to the diagram of FIG. 2, where the value of the pressure on the horizontal axis Pi is the pressure indicated by the load signals L, and the feedback pressure for the control algorithm is represented by the signal P, corresponding to the pressure Po in the diagram of FIG. 2.

(26) As in the systems according to FIGS. 7 to 10, the electronic units 16 and 116 can execute different programs, derived from two different algorithms. The units 16 and 116 communicate with the unit 1016 through the lines 23 and 123. Such as by signals comprising communication protocols, or alternatively a set of hard-wired handshake signals. Through the lines 23 and 123, the units 16 and 116 communicate respective auto-diagnosis signals to the unit 1016 which is designed to execute diagnostic procedures to verify the correct operation of the units 16 and 116, using a dedicated algorithm.

(27) The unit 1016 controls the state of a switching device 30. This device 30 can be constructed using electromechanical (relay) or solid-state switches, and has two outputs which, via drive circuits 31, 131, control the state of the solenoids 12a and 13a of the solenoid valves 12 and 13.

(28) The unit 1016 determines which of the two units 16 and 116 the direct control of the solenoids 12a and 13a is to be assigned to initially, by coupling the outputs of the switching device 30 selectively to the outputs X1, X2 of the unit 16 or to the outputs X11 and X12 of the control unit 116. The unit 1016 verifies that the selected control unit is correctly executing the predetermined pneumatic function, for example the function according to the characteristic shown in FIG. 2.

(29) The unit 1016 is also designed to periodically cause the switching of the switching device 30, assigning the control of the solenoids 12a and 13a to one and the other of the units 16, 116 in alternate periods, to verify the availability of these units, that is to say to verify that both are capable of executing the control of said solenoids, in case one of these two units proves to be longer capable of controlling said solenoids according to the pneumatic function to be executed.

(30) FIG. 12 shows a further embodiment in which the electronic switches 19, 20, 119 and 120 are connected to one another and to the solenoids 12a and 13a in the way shown in FIG. 7. However, the embodiment according to FIG. 12 can be implemented not only with the configuration according to FIG. 7, but with any one of the other configurations described above.

(31) In the system according to FIG. 12, the control units 16 and 116 are monitored by respective monitoring and diagnostic devices 16M and 116M, constructed with the use of microcontrollers, for example.

(32) When a monitoring device 16M or 116M detects an operating anomaly or fault in the associated unit 16 or 116, it disables the logic signals sent by the associated unit 16 or 116 to the corresponding switches 19, 20 or 119, 120, for example by adjusting the associated bias circuits 17, 18 or 117, 118.

(33) In these embodiments, the units 16, 116, as well as the monitoring and diagnostic devices 16M, 116M if necessary, can be integrated into a single device, for example a dual core chip or FPGA device.

(34) In one embodiment, an assembly includes a supply valve configured to be disposed between a chamber and a pressure source, a discharge valve disposed between the chamber and an external atmosphere, and a first control unit coupled with the supply valve by a first switch and with the discharge valve by a second switch. The first control unit is configured to output signals to the first switch and the second switch to control the supply valve and the discharge valve. The assembly also includes a second control unit coupled with the discharge valve by a third switch and a fourth switch. The second control unit is configured to output signals to the third switch and the fourth switch to control the supply valve and the discharge valve.

(35) Optionally, the supply valve and the discharge valve are configured to increase a pressure in the chamber responsive to the signals from the first control unit conflicting with the signals from the second control unit.

(36) Optionally, the supply valve and the discharge valve are configured to decrease a pressure in the chamber responsive to the signals from the first control unit conflicting with the signals from the second control unit.

(37) Optionally, the supply valve and the discharge valve are configured to increase a pressure in the chamber responsive to the signals from the first control unit matching the signals from the second control unit.

(38) Optionally, the supply valve and the discharge valve are configured to decrease a pressure in the chamber responsive to the signals from the first control unit matching the signals from the second control unit.

(39) Optionally, the supply valve and the discharge valve are coupled with each other in a series.

(40) Optionally, the supply valve and the discharge valve are configured to be coupled with the chamber with the chamber between the supply valve and the discharge valve.

(41) In one embodiment, an assembly includes a first control unit coupled with a supply valve by a first switch and with a discharge valve by a second switch. The first control unit is configured to output signals to the first switch and the second switch to control the supply valve and the discharge valve to control a pressure inside a chamber. The assembly also includes a second control unit coupled with the discharge valve by a third switch and a fourth switch. The second control unit is configured to output signals to the third switch and the fourth switch to control the supply valve and the discharge valve. The first control unit and the second control unit are configured to output the signals such that the supply valve and the discharge valve open or close based on whether the signals from the first control unit match or conflict with the signals from the second control unit.

(42) Optionally, the first control unit and the second control unit are configured to control the supply valve and the discharge valve to increase a pressure in the chamber responsive to the signals from the first control unit conflicting with the signals from the second control unit.

(43) Optionally, the first control unit and the second control unit are configured to control the supply valve and the discharge valve to decrease a pressure in the chamber responsive to the signals from the first control unit conflicting with the signals from the second control unit.

(44) Optionally, the first control unit and the second control unit are configured to control the supply valve and the discharge valve to increase a pressure in the chamber responsive to the signals from the first control unit matching the signals from the second control unit.

(45) Optionally, the first control unit and the second control unit are configured to control the supply valve and the discharge valve to decrease a pressure in the chamber responsive to the signals from the first control unit matching the signals from the second control unit.

(46) In one embodiment, an assembly includes a supply valve and a discharge valve coupled in series with each other between a pressure source and an external atmosphere. The supply valve and the discharge valve are configured to be coupled with a chamber that is pressurized by the pressure source. The assembly also includes a first control unit coupled with the supply valve by a first switch and with the discharge valve by a second switch. The first control unit is configured to output signals to the first switch and the second switch to control the supply valve and the discharge valve. The assembly also includes a second control unit coupled with the discharge valve by a third switch and a fourth switch. The second control unit is configured to output signals to the third switch and the fourth switch to control the supply valve and the discharge valve.

(47) Optionally, the supply valve and the discharge valve are configured to increase a pressure in the chamber responsive to the signals from the first control unit conflicting with the signals from the second control unit.

(48) Optionally, the supply valve and the discharge valve are configured to decrease a pressure in the chamber responsive to the signals from the first control unit conflicting with the signals from the second control unit.

(49) Optionally, the supply valve and the discharge valve are configured to increase a pressure in the chamber responsive to the signals from the first control unit matching the signals from the second control unit.

(50) Optionally, the supply valve and the discharge valve are configured to decrease a pressure in the chamber responsive to the signals from the first control unit matching the signals from the second control unit.

(51) Optionally, the supply valve and the discharge valve are coupled with each other and with the chamber with the chamber disposed between the supply valve and the discharge valve.

(52) Optionally, the supply valve is a solenoid valve.

(53) Optionally, the discharge valve is another solenoid valve.

(54) The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description may include instances where the event occurs and instances where it does not. Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it may be related. Accordingly, a value modified by a term or terms, such as “about,” “substantially,” and “approximately,” may be not be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges may be identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

(55) This written description uses examples to disclose the embodiments, including the best mode, and to enable a person of ordinary skill in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The claims define the patentable scope of the disclosure, and include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.