WO2008086980A1

WO2008086980A1 - Vehicle with pre-safe sensor system

Info

Publication number: WO2008086980A1
Application number: PCT/EP2008/000164
Authority: WO
Inventors: Falk Schumann; Bernd Wagner
Original assignee: Daimler Ag
Priority date: 2007-01-19
Filing date: 2008-01-11
Publication date: 2008-07-24
Also published as: DE102007002842A1

Abstract

Vehicle with pre-safe sensor system (10) which, in driving situations in which there is the likehood of an accident, generates pre-safe signals for activating pre-safe devices, wherein an actuator device (5, 6, 13) which reacts to the pre-safe signals is provided for opening a clutch (2) which is arranged in the drive train between the engine (1) and the driven vehicle wheels (4).

Description

Vehicle with pre-safe sensor

The invention relates to a vehicle with a pre-safe sensor system which generates pre-safe signals for activation of pre-safe devices in case of accident-prone driving situations.

Such vehicles are known from DE 103 38 760 Al. According to this document, the pre-safe sensor system can detect potential collision objects, so that in principle any pre-safe devices can act in order to avoid a collision or initiate measures to reduce collision consequences.

In an emergency braking the drive connection between an engine of the vehicle and driven vehicle wheels should be separated as quickly as possible. This can be prevented that the brakes must additionally counteract the engine torque and the braking effect is reduced accordingly. Therefore, it is an object of the invention to provide vehicles that always ensure a maximum effect of the brakes in the event of emergency braking, in particular, should ensure that the drive torque of the engine can not reduce the effect of the brakes.

This object is achieved in a vehicle of the type specified according to the invention that a responsive to the pre-safe signals actuator device for opening a drive train between the engine and driven vehicle wheels arranged clutch is provided.

The invention is based on the general idea, in an accident-prone driving situation forcibly decoupling the vehicle engine from the driven wheels of the vehicle, so that the effect of the wheel brakes of the vehicle is increased.

The clutch may, for example, as an automated clutch between the engine and, for example, an automated manual transmission, a

Dual clutch transmission or an automatic transmission with multiple coupled planetary gear sets be executed. It is also possible that the clutch is designed as a so-called lockup clutch, which serves to bridge a hydrodynamic torque converter. It is also conceivable that the clutch is designed as a clutch within an automatic transmission with multiple coupled planetary gear sets and by opening the clutch, a neutral position of the automatic transmission is engaged.

In vehicles with manually shifted transmissions and driver-operated clutch in the drive train between the engine and driven wheels, the driver should open the clutch as early as possible in an emergency braking to avoid that the brakes must also counteract the engine torque and the braking effect is reduced accordingly. This is ensured according to the invention by providing an actuator device that reacts to the pre-safe signals on a driver-side actuated, that is, a so-called foot-force-actuated clutch. According to an expedient embodiment of the invention, a motor control responsive to the pre-safe signals is additionally provided, which keeps the engine speed below a predetermined low threshold value upon receipt of pre-safe signals in order to prevent the engine from overspeeding. even if the driver should operate the accelerator pedal with the clutch disengaged.

According to a structurally preferred embodiment of the invention, the normally driver side actuated clutch can be configured as a hydraulically actuated clutch with a hydraulic sender unit operable on the driver side and a hydraulic slave unit arranged on the clutch side and the slave unit can be connected to a hydraulic pressure source via a valve arrangement controllable by the pre-safe sensor system , In this case, the hydraulic pressure source can be formed by the pressure side of a suction side connected to a hydraulic reservoir pump or by an automatically recharged by a pump pressure accumulator.

Suitably, the valve arrangement is designed such that the slave unit is hydraulically blocked by the valve assembly in the actuated state. Thus, the open state of the clutch can be maintained without the need for hydraulic power would be necessary.

Said object is also achieved by a method according to claim 7, wherein upon detection of a strong deceleration, the drive train by means of a between a motor and driven vehicle wheels arranged, controllable clutch is separated. The coupling can be designed according to the coupling of claim 1.

As a strong delay, for example, a so-called full braking can be detected. A strong delay can be detected, for example, if the acceleration falls below a first limit value and / or the gradient of the acceleration falls below a second limit value.

Otherwise, with regard to preferred features of the invention, reference is made to the claims and the following explanation of the drawings, with reference to which a particularly preferred embodiment of the invention will be described in more detail.

Protection is claimed not only for explicitly specified or illustrated combinations of features but also for any combination of the features shown or indicated in principle.

In the drawing, the only Fig. Shows a schematics schematized

Representation of a vehicle according to the invention.

According to the drawing has a not-shown motor vehicle for its drive an internal combustion engine 1, which is drivingly connected via a normal driver side actuated clutch 2 and a manually shiftable transmission 3 with drivable wheels 4 of the vehicle.

The clutch 2 is normally closed and can by means of a hydraulic Nehmeraggregates 5 against a Resetting force to be opened. The slave unit 5 is hydraulically connected via a normally position I engaging control valve assembly 6 with a donor unit 7, which is the driver side via a pedal 8 actuated. When the pedal 8 is not actuated, the piston working space of the master unit 7 is connected to a relatively unpressurized hydraulic reservoir 9. If the pedal 8 is actuated, the drivingly coupled to the pedal 8 piston of the master unit 7 on the connection of the hydraulic reservoir 9 (in the drawing to the left) pushed away, so that upon further actuation of the pedal 8 hydraulic medium from the master unit 7 and pushed into the Slave unit 5 is inserted and accordingly the clutch 2 is opened. As soon as the pedal 8 is no longer actuated, the clutch 2 closes, the piston of the slave unit 5 being pushed into its cylinder, so that hydraulic medium is pushed out of the slave unit 5 and inserted into the master unit 7 until the operating state shown in the drawing is reached again ,

Furthermore, the vehicle has a pre-safe sensor 10, with the accident-prone driving situations, such as the risk of a collision of the vehicle, can be detected. Should such a situation occur, the pre-safe sensor 10 generates corresponding pre-safe signals, which are passed on to a control circuit 12 via a bus system, for example a CAN bus 11. This control circuit 12 then controls a driver circuit 12 'for a hydraulic pump 13 and a driver circuit 12''for actuating the control valve arrangement 6. This has the consequence that on the one hand the pump 13 is put into operation and on the other hand, the control valve assembly 6 in the state

11 is set. Thus, the pressure side of the suction side connected to the hydraulic reservoir 9 pump 13 is hydraulically connected to the slave unit 5, with the result that set by the control circuit 12 pump 13 hydraulic medium to the slave unit 5 passes and the clutch 2 is opened. Thus, the engine 1 is decoupled from the drive wheels 4, so that the engine 1 can no longer reduce the effect of a service brake of the vehicle. In order to prevent overspeeding of the motor 1 decoupled from the drive wheels 4 under all circumstances, the pre-safe signals are also supplied to a motor control 14, which then reverses the motor 1 to a predetermined minimum speed or stops.

Optionally, the control circuit 12 switch the control valve assembly 6 in the switching state III at a long-term danger condition, so that the slave unit 5, which assumes its state for open clutch 2, is hydraulically blocked in this state. Thus, the clutch 2 remains independent of the operation of the pump 13, which is now stopped by the control circuit 12, in the open state.

When a the operating state of the pedal 8 and the encoder unit 7 detecting the sensor 15 reports that the pedal 8 is not actuated, and if furthermore, the engine controller 14 notifies an engine speed of, for example below 2000 min ^"1 and when the pre-safe sensor system 10 after elimination of a collision danger no Pre-Safe signals generated more, the control circuit

12, the control valve assembly 6 in turn in the Switching state I pass, so that the clutch 2 is subsequently only operable on the driver side.

The pressure side of the pump 13 may be assigned according to the drawing, a pressure relief valve 16, so that the pressure of the inserted from the pump 13 into the master unit 5 hydraulic medium remains correspondingly limited and under no circumstances on the clutch 2 destructive restoring forces can be exercised. Optionally, the clutch 2 may be associated with a sensor, not shown, which registers whether the clutch 2 is closed or opened. If the corresponding signals are supplied via the bus 11 of the control circuit 12, this can operate or shut down the pump 13 and the control valve assembly 6 so that when the clutch 2 is open, no further hydraulic medium to the slave unit 5 is supplied. Instead of the aforementioned sensor on the clutch 2, a pressure sensor on the slave unit 5 may be arranged. When this pressure sensor reports vanishing pressure, the clutch 2 is closed; In contrast, the clutch 2 is opened when the pressure sensor reports the exceeding of a predetermined pressure threshold.

If the vehicle has no pre-safe sensor, the described clutch can also be opened when a strong deceleration of the vehicle is detected. A strong delay can be detected, for example, if the acceleration falls below a first limit value and / or the gradient of the acceleration falls below a second limit value.

In another structure of the powertrain, for example with an automated clutch or an automatic transmission with several coupled Planet sets the drive train can be separated in another way, for example by opening the automated clutch or setting a neutral position in the automatic transmission.

Claims

claims

1. vehicle with pre-safe sensor system (10), which generates in case of accident prone driving situations pre-safe signals for the activation of pre-safe devices, characterized in that a responsive to the pre-safe signals actuator device (5,6 , 13) is provided for opening a arranged in the drive train between the engine (1) and driven vehicle wheels (4) coupling.

2. Vehicle according to claim 1, characterized in that the clutch is designed as a normally driver-side operated clutch (2).

3. Vehicle according to claim 2, characterized in that the coupling (2) between the engine (1) and a manually operated transmission (3) is arranged.

4. Vehicle according to one of claims 1, 2 or 3, characterized in that a responsive to pre-safe signals engine control (14) is provided and keeps the engine speed below a predetermined threshold or lowers.

5. Vehicle according to one of claims 1 to 4, characterized in that a hydraulically actuated clutch (2) with a driver side operable hydraulic sender unit (7) and a hydraulic slave unit (5) arranged on the coupling side, and the slave unit (5) can be connected to a hydraulic pressure source (13) via a valve arrangement (6) controllable by the pre-safe sensor system (10).

6. Vehicle according to claim 5, characterized in that the slave unit (5) by the valve assembly (6) is hydraulically blocked.

7. A method for operating a drive train of a vehicle, wherein between a motor and driven vehicle wheels, a controllable clutch is arranged, wherein upon detection of a strong delay, the drive train is separated by means of said coupling.