DE4420116A1 - Retarder control - Google Patents

Abstract

The invention concerns a method of ensuring that the speed of a vehicle with service brakes and auxiliary deceleration devices such as a retarder, engine brake and/or means of engagement in the gearbox control when the vehicle is travelling downhill, does not exceed a preset reference speed. The vehicle registers coasting condition and when it switches to coasting, the instantaneous speed (V) is stored as a reference speed (Vs). The auxiliary deceleration devices (28, 30, 32) are controlled individually or in combination in such a way that the instantaneous speed (V) does not exceed the reference speed (Vs).

Description

The invention relates to a device for automati actuation of an additional vehicle braking system.

In addition to the service brakes of a vehicle, in particular re of a commercial vehicle, which is usually a wear and tear underlying friction brakes are additional Ver Delay facilities more and more by lawmakers required and offered by the vehicle manufacturers.

Such wear-free additional delays Directions such as retarders and engine brakes can be used be applied, the vehicle speed on the downhill con keep stant.

The retarders are both attached to the gearbox ordered hydrodynamic, hydrostatic or electrodynamic Mix braking devices understood, as well Systems in the form of an "intarder" within the Ge gear housing are provided.

Retarders are further differentiated into primary retarder those that work depending on the engine speed, and in secondary retarders depending on the driving working speed.

For the actuation of the retarder are different Differentiated species. The braking effect can be within the maximum performance of the retarder in steps or can be steplessly controlled.

First of all, actuation by a brake step switch, usually in the form of a steering column lever or one Switch that is in the immediate vicinity of the steering wheel for the driver is conveniently located, several braking levels on.  

A brake level switch is also used in conjunction with a step plate that the driver in the footwell weighed in combination with the service brakes as a brake dal can be operated with the foot.

The retarder is un in the different braking levels used differently. In known systems the desired braking effect over the braking levels switch set and the speed reached instantaneously speed by pressing an additional switch for example, a button on the brake level switch, saved chert. The stored speed is held and the brake level switch is again in position "0" brings. To delete the saved speed in any changed position of the braking levels the additional switch is actuated again.

EP 0 336 913 describes a method and an arrangement became known at which the speed of a Vehicle downhill can be kept constant. Here the driver activates the brake via, for example Brake pedal. The lowest speed that the driving tool achieved during the braking process is the target value stored in a control unit. Via the brake pedal become retarders as well as service brake and exhaust brake activated. The harder the brake pedal is pressed the more the retarder brakes switched on. From a predetermined brake pedal actuation the service brake is activated. Will the target value reached, the brake pedal can be released. A Ge Speed control system controls retarder and exhaust brake. The current speed becomes the target speed approximated by activating all brakes. When the driver releases the brake pedal, retarders and stop Exhaust brakes the speed automatically until is accelerated again.  

The auxiliary brakes can also be equipped with one, for example five stage shift lever can be activated. A button on this Shift lever activates speed control.

The known brake systems have different Situations still have serious disadvantages.

For example, for vehicles used for the train were equipped with a cruise control, the Geschwin for train operation (engine control) and braking operation (retarder control) with two different controls elements set.

This system separation is complex for the driver and can lead to incorrect operation. For example, if the pro programmed braking speed below the programmed train speed, this can lead to both Systems work against each other.

The invention has for its object the Betäti supply of the auxiliary brakes of a motor vehicle to constant maintain a speed to simplify and misuse avoidance. Another task is the unequivocal Restricted usability of the retarder actuation by the driver rer via brake level switch and / or brake pedal for ver reduction or adaptation of the vehicle speed.

The object is achieved by the invention Regulation of the additional brakes, different functions encoder signals to an electronic control device ben and signals are generated in this control device, those for the control of retarder, exhaust brake and Ge drive circuit can be used.

Required for the function of the rain according to the invention lung is a signal generator in the form of an accelerator switch.  

This accelerator switch gives the "0" position Accelerator pedal, i.e. when the pedal is not depressed Signal G = 0 to an electronic control unit. This Signal G = 0 is also issued when there is no drive The fuel supply of the injection pump is present (overrun). A speed sensor is also required emits a signal to the electronic control unit from which the current driving speed is calculated. A temperature sensor is also required Signal in the electronic control unit the current what temperature of the vehicle cooling circuit can be calculated.

In addition to the required sensors mentioned above signal transmitters are added, their output values if supplied to the electronic control unit. In addition to the additional signal transmitters, there is a brake pedal scarf to count. When the brake pedal is depressed, a signal is generated B = 1 given, for example, the brake light signal corresponds.

The arrangement of a retar is also possible the brake level switch. The retarder brake level switch can be integrated in the brake pedal or it is on arranged another location of the brake system, for example wise near the steering wheel, for example as a steering stick lever or as a keyboard on the dashboard. Is the retarder brake level switch integrated in the brake pedal, so when pressing the brake pedal, the Retarder and also when the brake pedal is pressed further the service brakes are activated.

If a brake level is selected with the brake level switch, the electronic control unit receives a signal I <0 given. If there is an additional one in the brake level switch Function to keep a given speed constant is available and this function is switched on, a signal T = 1 is supplied to the electronic control unit  leads. This signal can be switched by an additional switch in the brake switch or, for example, in a be agreed braking level are given.

As a further additional function generator, a tem pomat or an electronic accelerator pedal (e-gas switch) possible for example for train operations. Once the one injection pump is switched to overrun mode, is from the Cruise control electronics a signal T = 1 to the electronic Control unit issued.

The electronic control from the function providers Device supplied signals are ver in this control unit works and to control functional elements of the Vehicle used.

In addition to the retarder as a functional element, a Motor brake can be controlled. The engine brake can be used as Exhaust flap brake to be designed or as a con Stantdrossel or as a braking device that over the Valve train of the engine is controlled. Combinations too these engine braking devices are possible. All furnishings Settings and combinations can be single-stage or multi-stage being controlled.

Interventions in the gear shift for additional braking is possible. This can be done through the electroni cal control unit an automatic or semi-automatic Gear shift or an electronic gear shift recommended. Because of the engine brakes devices to achieve braking effect from the engine speed is dependent, the braking effect can be controlled by a Intervention in the transmission control can be increased by at for example automatically through the electronic control is shifted into a lower gear. Likewise, at  a hydrodynamic retarder through an increased engine speed the heat dissipation of the retarder in the vehicle cooling system circulation can be increased.

By the inventive method, the Ge speed of a vehicle on a downhill slope is constant being held. In an electronic tax device after signals generated by different encoders processed a given program and signals Functional elements of the brake system of the vehicle passed ben.

The program carried out in the electronic control unit The process is divided into different functional groups, from which some function groups represent basic functions and other functional groups are also selected that can.

The method according to the invention is based on figures explained in more detail.

Show it:

Fig. 1 is a diagram of components of the controller;

Fig. 2, the two basic functional groups;

Fig. 3 shows a possible combination of Fig. 2;

Fig. 4 shows another possible combination according to Fig. 2 and

Fig. 5 shows a further combination possibility of FIG. 2.

Fig. 1 shows the representation of the individual Be components for operating the proposed method. The sensors in the vehicle are shown here as symbols. An accelerator pedal 2 emits a signal "G" which is equal to "ZERO" when the accelerator pedal is not actuated and jumps to a value of "ONE" when actuated. This jump function is shown symbolically in function block 4 . The signal "G" is fed to an electronic control unit 6 .

A brake pedal 8 emits a signal "B", which is equal to "ZERO" when the brake pedal is not actuated and jumps to a value "ONE" when actuated. This jump function is shown symbolically in the function block 10 . The signal "B" can also be generated via a pressure switch, not shown here, integrated in the brake system of the vehicle. The signal "B" is fed to the electronic control unit 6 . The brake pedal 8 can be provided with an integrated retarder actuation, the function of which is the same as that of another transmitter, the brake level switch 12 . The brake level switch 12 emits a signal "I", which is formed between a zero position and a maximum value in several stages. This staircase function is shown symbolically in function block 14 . The signal "I" is fed to the electronic control unit 6 . Since the signal "I" can be generated both in an external brake stage switch 12 and via the integrated retarder actuation in the brake pedal 8 , both encoders 8 and 12 are connected to the function block 14 .

A cruise control or E-gas switch 16 emits a signal "T", which is equal to "ZERO" during train operation, which corresponds to a promotion of the injection pump, and when the injection pump delivery quantity is set to "ZERO", that is, overrun, a jump executes a value of "ONE". This jump function is shown symbolically in the function block 18 . The signal "T" can also be entered manually by the driver via a button or switch integrated in the brake level switch 12 , not shown here. The signal "T" is the electronic control unit 6 leads.

A vehicle speed sensor 20 emits a signal "V" which speaks to the instantaneous speed present. The function corresponding to the sensor signal is represented symbolically in function block 22 . The signal "V" is fed to the electronic control unit 6 .

A temperature sensor 24 emits a signal "δ" which corresponds to the temperature of the coolant in the coolant circuit of the vehicle. A possible course of the rising temperature in the function block 26 is shown symbolically. The signal "δ" is the electronic Steuerge advises 6 supplied.

In the electronic control unit 6 , the incoming signals are prepared according to program sequences described later and signals are formed which are used to control functional elements for influencing the braking behavior of the vehicle. 1, a retarder 28 , a motor brake 30 and engagement means in the transmission circuit 32 are shown as functional elements . The function block 34 shows the function curve of the braking torque of the retarder 28 , function block 36 the function curve of the braking torque of the engine brake 30 , each in dependence on the instantaneous speed "V". Function block 38 shows the staged course of the engine speed in the different gear steps depending on the instantaneous speed "V". The functional block 40 shows the basic representation of the course of the total braking torque of the functional elements 28 , 30 , 32 controlled by the electronic control unit 6 .

Fig. 2 shows the basic function group 42 in the program sequence according to the inventive method. The signal "G" emitted by the gas pedal 2 is constantly checked within the electronic control unit 6 . For this purpose, a program provided in the control unit passes through a comparison block 44 several times per second within the function group 42 , in which it is queried whether the accelerator pedal 2 is released and the injection pump delivery quantity is therefore “ZERO”. If the accelerator pedal 2 is depressed, the signal "G = 1" is present and the query for "G = 0?" will be answered with "NO". In this case, an auxiliary signal "g" is set to "ZERO" by a program block 46 ("g = 0") and a return is made in the program sequence before the comparison block 44 . As long as the signal "G = 1" is present, the loop is continuously repeated by blocks 44 and 46 . In this case, a speed control by the electronically controlled functional elements 28 , 30 , 32 does not take place.

However, if the "G = 0" signal is present after the accelerator pedal 2 is released and the query in the comparison block 44 is answered with "YES", the program flow comes to a further comparison block 48 in which the auxiliary signal "g" is queried ("g = 0? "). If this query is answered with "YES", this means that comparison block 48 is run through for the first time after the accelerator pedal is released. In this case, a program block 50 is run through in the program sequence, which stores the present instantaneous speed "V" as the setpoint speed "V _S " to be kept constant. Subsequently, the auxiliary signal "g" is set to "ONE" by a program block 52 ("g = I").

The program flow leaves the functional group 42 towards the program block 52 . Function group 42 is also left if the query "g = 0?" is answered in comparison block 48 with "NO". This answer "NO" is always the case when the accelerator pedal is not used for a long time.

Function group 42 is followed by a function group 54 . This function group 54 has a program block 56 through which a control signal 58 is modulated in such a way that the functional elements 28 , 30 , 32 are controlled such that the instantaneous speed "V" of the vehicle does not become greater than the target speed "V _S ". The signal 58 is, as described above, in addition to the control of the brake system also used to control a transmission process with the additional Bremswir effect shown above.

In vehicles with cruise control 16 or E-gas (electronic accelerator pedal), the function group 42 can be replaced by a function group 60 . Such an arrangement of required functional groups is shown in FIG. 3. As soon as the cruise control 16 switches to overrun mode, ie the injection pump no longer delivers, a signal "T = 1" is output from the electronic control unit 6 by the cruise control 16 .

The signal "T" is queried in a comparison block 62 within the function group 60 , whether the cruise control 16 is switched to overrun mode and thus the injection pump delivery rate is "ZERO". If there is overrun operation, the signal "T = 1" is present and the query for "T = 1?" is answered with "YES". If there is no overrun operation and thus the injection pump delivery rate has not gone to "ZERO", an auxiliary signal "t" is set to "ZERO" by a program block 64 ("t = 0") and a jump back in the program sequence is made before comparison block 62 . As long as the signal "T = 1" is not present, the cruise control 16 regulates the speed in train operation, the program loop is repeated by blocks 62 and 64 . In this case, the electronically controlled functional elements 28 , 30 , 32 do not regulate the speed.

If, however, the signal "T = 1" is present at the comparison block 62 during overrun operation, the program flow arrives at a further comparison block 66 which queries the auxiliary signal "t"("t = 0?"). If this query is answered with "YES", this means that comparison block 66 is run through for the first time after the switch to overrun mode. In this case, a program block 68 is run through in the program sequence, which stores the present instantaneous speed "V" as the setpoint speed "V _S " to be kept constant. Subsequently, the auxiliary signal "t" is set to "ONE" by a program block 70 ("t = 1").

The program flow leaves the functional group 60 to the program block 70 . Function group 60 is also left if the query "t = 0?" is answered with "NO" in comparison block 66 . This answer "NO" is always the case when the overrun operation is already ongoing.

Function group 70 is in turn followed by a function group 54 . This function group 54 has a program block 56 through which a control signal 58 is modulated in such a way that the functional elements 28 , 30 , 32 are controlled such that the instantaneous speed "V" of the vehicle does not become greater than the target speed "V _S ". The signal 58 is, as described above, in addition to the control of the brake system also used to control a transmission process with the additional Bremswir effect shown above.

FIG. 4 shows the electronic control unit 6 with an additional function group 72. This function group 72 can alternatively connect to a function group 42 in a vehicle without cruise control 16 or to a function group 60 in a vehicle with cruise control or E-gas 16 and lies in the program flow between function group 42 or function group 60 and function group 54 . The arrangement with a functional group 42 is shown by way of example in FIG. 4. The arrangement with a function group 60 applies accordingly.

If the brake pedal 8 is actuated, the signal "B = 1" is generated. The signal "B" is checked by a comparison block 76 in the function group 72 . Is the signal "B = 1", so the brake pedal 8 is actuated, it is checked by a comparison block 78 whether the torque speed "V" is less than the defined target speed "V _S ". If the instantaneous speed "V" is below the target speed "V _S ", the instantaneous speed "V" is stored as a braking speed "V _B " by a program block 80 . The program sequence then exits function group 72 .

If the instantaneous speed "V" is not below the target speed "V _S ", the target speed "V" remains unchanged and the program flow exits function group 72 .

If the signal "B" is not equal to "ONE", the brake pedal is no longer actuated, the new target speed "V _S " is set equal to the current braking speed "V _B " by a program block 72 . The program sequence then leaves function group 72 . The target speed "V _S " is corrected to lower values if the instantaneous speed "V" is lower at the end of the braking process than at the beginning of the overrun operation.

The function group 54 is connected to the function group 72 in the program sequence according to FIG. 4, where a signal 58 is generated which controls the function elements 28 , 30 , 32 in such a way that the instantaneous speed "V" is kept below the target speed "V _S " becomes.

Fig. 5 shows an electronic control unit 6 with an additional function group 84 in addition to other function groups. This functional group 84 can alternatively connect to a functional group 42 in a vehicle without a speed mat 16 or to a functional group 60 in a vehicle with cruise control 16 or E-gas or also to a functional group 72 . The function group 84 lies in the program sequence between function group 42 or function group 60 or function group 72 and in each case the function group 54 .

The arrangement with a function group 42 and a connected function group 72 is shown by way of example in FIG. 5. The arrangement with a functional group 60 or a functional group 60 and a functional group 72 applies accordingly.

If the retarder 28 is actuated by the driver of the vehicle, for example via a brake level switch 12 on the steering wheel or a step plate of the brake pedal, the signal "I <0" is generated. The signal "I" is checked by a comparison block 86 in the function group 84 . If the signal "I <0" is present, so the retarder 28 is actuated, a comparison block 88 checks whether the momentary speed "V" is less than the defined target speed "V _S ". If the instantaneous speed "V" is below the desired speed "V _S ", the instantaneous speed "V" is stored as a retarder speed "V _I " by a program block 90 . The program sequence then exits function group 84 .

If the instantaneous speed "V" is not below the target speed "V _S ", the target speed "V" remains unchanged and the program flow exits function group 84 .

If the signal "I" is not greater than "ZERO", so that the retarder is no longer actuated by the driver, the new target speed "V _S " is set to the current retarder speed "V _I " by a program block 92 . The program sequence then exits function group 84 . The function group 54 is also connected to the function group 84 in the program flow according to FIG. 5, where a signal 58 is generated which controls the function elements 28 , 30 , 32 in such a way that the instantaneous speed "V" below the target speed "V _S " is held.

Fig. 6 shows an electronic control unit 1 with an additional functional group 94 tion groups in addition to other radio. This function group 94 is independent of the other function groups and can alternatively be combined with other function groups. A specific position in the program flow is not a requirement. In FIG. 6, the function group 94 group in the program sequence to the function connected 54, but this should apply only exemplary. The arrangement following other functional groups applies accordingly.

The temperature signal "δ" is checked by a comparison block 96 in the function group 94 . The temperature signal "δ" represents the current water temperature in the cooling circuit of the vehicle. If the temperature signal "δ" is above a predetermined limit temperature "δ _G ", a signal "MB = 1" is generated by a program block 98 , which is the engine brake operated. - The program flow then leaves function group 94 .

Due to the temperature-dependent connection of the motor The effect of the temperature-dependent return will brake regulation of the retarder braking effect is reduced because the retar which depends on the temperature in the cooling circuit must be taken to damage, for example a Avoid overheating the engine.

The proposed method can also be used in a combination between the functional groups 42 , 54 , 60 , 72 , 84 , 94 presented and an anti-lock system and / or an anti-slip system, not shown here. When the clutch is actuated, an additional device can be used to switch off the engine brake in order to prevent the engine from stalling.

Reference list

2 accelerator pedal
4 function block
6 electronic control unit
8 brake pedal
10 function block
12 brake level switches
14 function block
16 cruise control
18 function block
20 driving speed sensor
22 function block
24 temperature sensor
26 function block
28 retarders
30 engine brake
32 gear shift
34 function block
36 function block
38 function block
40 function block
42 functional group
44 block of comparison
46 program block
48 block of comparison
50 program block
52 program block
54 function group
56 program block
58 control signal
60 function group
62 block of comparison
64 program block
66 block of comparison
68 program block
70 program block
72 function group
76 block of comparison
78 block of comparison
80 program block
82 program block
84 functional group
86 block of comparison
88 block of comparison
90 program block
92 program block
94 functional group
96 comparison block
98 program block

Claims (27)

1. A method for avoiding exceeding a predetermined target speed of a motor vehicle with service brakes and additional deceleration devices when driving downhill on slopes, characterized in that overrun mode is registered on the vehicle, that when switching to overrun mode the instantaneous speed (V) as a target speed (VS) is stored and that the additional delay devices ( 28 , 30 , 32 ) are controlled individually or in combinations so that the instantaneous speed (V) does not exceed the target speed (VS). 2. Method for avoiding exceeding a target speed according to claim 1, characterized in that by loosening a gas pedal ( 2 ) is switched to overrun. 3. A method to avoid exceeding a target speed according to claim 1, characterized in that a cruise control ( 16 ) is switched to overrun. 4. A method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that a retarder ( 28 ) is used as an additional delay device. 5. A method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that in addition a motor brake ( 30 ) is used as a deceleration device. 6. A method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that in addition a transmission circuit ( 32 ) is used as a delay device. 7. The method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that the service brakes of the vehicle are activated by actuation of a brake pedal ( 8 ). 8. A method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that the control of the additional delay devices ( 28 , 30 , 32 ) is carried out by a control signal ( 58 ) generated in an electronic control unit ( 6 ). 9. A method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that the control of the additional delay device ( 28 , 30 , 32 ) can be superimposed by signals triggered by the driver for activating the retarder ( 28 ). 10. A method for avoiding exceeding a target speed according to claim 9, characterized in that a superimposed signal for activating the retarder ( 28 ) is triggered by actuating a brake level switch ( 12 ). 11. A method to avoid exceeding a target speed according to claim 9, characterized in that the brake step switch ( 12 ) is actuated by a brake pedal ( 8 ), which triggers an overlaying signal to activate the retarder ( 28 ). 12. The method for avoiding exceeding a target speed according to claim 11, characterized in that the service brakes are additionally activated by actuating the brake pedal ( 8 ) first of the brake level switch ( 12 ) and upon further depression of the brake pedal ( 8 ). 13. A method for avoiding exceeding a target speed according to one of the preceding claims, characterized in that the tempera ture ( 8 ) of a coolant circuit of the vehicle is regi strated and the engine brake ( 30 ) is actuated when a predetermined limit temperature (δ _G ) is exceeded. 14.Device for avoiding exceeding a predetermined target speed of a motor vehicle with service brakes and additional delay devices when driving down a hill and with an electronic control unit which is connected to sensors and controls the additional delay device, as characterized in that the sensor ( 2 , 12 , 16 ) are provided, which recognize coasting operation, that the control device ( 6 ) has means for storing the instantaneous speed (V) when switching to coasting operation as a target speed (V _S ) and that the additional deceleration devices ( 28 , 30 , 32 ) can be controlled individually or in combinations such that the instantaneous speed (V) does not exceed the target speed (V _S ). 15. Device for avoiding exceeding egg ner target speed according to claim 14, characterized in that an accelerator pedal ( 2 ) is provided as a sensor for detecting overrun operation. 16. A device to avoid exceeding egg ner target speed according to claim 14, characterized in that a cruise control ( 16 ) is provided as the encoder for detecting overrun operation. 17. A device to avoid exceeding egg ner target speed according to claim 14, characterized in that a brake stage switch ( 12 ) with integrated switch for switching off the injection pump delivery is seen as a sensor for detecting overrun operation. 18. Device for avoiding exceeding egg ner target speed according to one of the preceding claims 14 to 17, characterized in that a retarder ( 28 ) is provided as an additional delay device. 19. Device for avoiding exceeding egg ner target speed according to one of the preceding claims 14 to 18, characterized in that in addition a motor brake ( 30 ) is provided as a device delay device. 20. Device for avoiding exceeding egg ner target speed according to one of the preceding claims 14 to 19, characterized in that additional means for gear shifting ( 32 ) are provided as a delay device. 21. Device to avoid exceeding egg ner target speed according to one of the preceding claims 14 to 20, characterized in that a brake pedal ( 8 ) is provided for actuating the service brakes of the vehicle. 22. Device for avoiding exceeding a set speed according to one of the preceding claims 14 to 21, characterized in that sensors ( 8 , 12 ) are provided which generate signals triggered by the driver for activating the retarder ( 28 ) which are used to control the additional delay devices ( 28 , 30 , 32 ) are superimposed. 23. The device for avoiding exceeding egg ner target speed according to claim 22, characterized in that the transmitter for generating the signal for activating the retarder ( 28 ) is a braking stage switch ( 12 ). 24. Device for avoiding exceeding egg ner target speed according to claim 22, characterized in that the transmitter for generating the signal for activating the retarder ( 28 ) in the brake pedal ( 8 ) integrated brake level switch ( 12 ). 25. The device for avoiding exceeding egg ner target speed according to claim 24, characterized in that the brake pedal ( 8 ) is designed such that it initially acts as a brake step switch ( 12 ) and additionally activated the service brakes upon further passage. 26. Device for avoiding exceeding egg ner target speed according to one of the preceding claims 14 to 25, characterized in that a temperature sensor ( 24 ) is provided which registers the temperature ( 8 ) of the coolant circuit of the vehicle. 27. The device for avoiding exceeding a target speed according to claim 23, characterized in that the Bremsstufenschal ter ( 12 ) has a button or switch which emits an overrun characteristic signal.