Vehicle having a belt pulley and standstill air-conditioning

Abstract

A vehicle including a combustion engine, a belt alternator starter, and a decouplable accessory power take-off for auxiliary units, wherein the accessory power take-off includes, as auxiliary units, at least an air-conditioning compressor and an electric motor as belt alternator starter that is usable as a motor and as a generator, wherein a coupling and a decoupling of the accessory power take-off occurs by means of a form-fitting clutch, and wherein at a standstill of the combustion engine during a short stop phase, a stationary air-conditioning operation occurs by means of a reverse rotation of the auxiliary units, and wherein a starting of the combustion engine after the short stop phase occurs by means of a reversal of the direction of rotation of the electric motor.

Claims

1. A vehicle comprising: a combustion engine; a belt alternator starter; and, a decouplable accessory power take-off for auxiliary units, wherein the accessory power take-off includes, as auxiliary units, at least an air-conditioning compressor and an electric motor as belt alternator starter that is usable as a motor and as a generator, wherein a coupling and a decoupling of the accessory power take-off occurs by means of a form-fitting clutch, and wherein at a standstill of the combustion engine during a short stop phase, a stationary air-conditioning operation occurs by means of a reverse rotation of the auxiliary units, and wherein a starting of the combustion engine after the short stop phase occurs by means of a reversal of the direction of rotation of the electric motor; wherein the coupling and the decoupling of the accessory power take-off occurs by means of a switchable pawl freewheel.

2. The vehicle recited in claim 1, wherein the switchable pawl freewheel comprises: a switching device; and, at least one generator pawl switchable from a locking position to a freewheel position by means of the switching device.

3. The vehicle recited in claim 2, wherein the switchable pawl freewheel comprises: a boost pawl that locks in a relative direction of rotation opposite a direction of rotation of the generator pawl.

4. The vehicle recited in claim 1, wherein the belt alternator starter is combined with a pulley decoupler.

5. The vehicle recited in claim 1, wherein a belt decoupler comprises a torsional vibration damper.

6. A method for operating the vehicle recited in claim 1, wherein during the standstill of the combustion engine during the short stop phase, the stationary air-conditioning operation occurs by means of the reverse rotation of the auxiliary units, and wherein the starting of the combustion engine after the short stop phase occurs by means of the reversal of the direction of rotation of the electric motor.

7. The method recited in claim 6, wherein a boost clutch is overrun in a freewheel-like way in the stationary air-conditioning operation.

8. The method recited in claim 6, wherein a polarity of the electric motor, which is usable as a belt alternator starter, is changed when a start of the combustion engine is requested after the short stop phase.

9. The method recited in claim 7, wherein a polarity of the electric motor, which is usable as a belt alternator starter, is changed when a start of the combustion engine is requested after the short stop phase.

10. The method recited in claim 8, wherein a generator pawl is switched to its locking position after the start of the combustion engine.

11. The method recited in claim 9, wherein a generator pawl is switched to its locking position after the start of the combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:

(2) FIG. 1 is a Cartesian coordinate diagram plotting a rotary speed over time to indicate the differences between a conventional stationary air-conditioning operation and a stationary air-conditioning operation in accordance with the invention;

(3) FIG. 2 shows three Cartesian coordinate diagrams in which a conventional starting operation out of a stationary air-conditioning operation is shown;

(4) FIG. 3 shows the coordinate diagrams of FIG. 2 in which a starting operation out of a stationary air-conditioning operation as proposed by the invention is shown;

(5) FIG. 4a is a simplified equivalent circuit diagram of a vehicle of the invention;

(6) FIG. 4b illustrates two rectangles indicating a freewheel during normal operation and during stationary air-conditioning operation; and,

(7) FIG. 5 illustrates two Cartesian coordinate diagrams in which a rotary speed and a pawl position are plotted over time.

DETAILED DESCRIPTION

(8) FIG. 1 illustrates a Cartesian coordinate diagram with an x axis 1 and a y axis 2. X axis 1 indicates the time in seconds. Y axis 2 indicates a rotary speed in a suitable unit. A region 3 below x axis 1 represents a stationary air-conditioning operation in accordance with the invention. A region 4 above x axis 1 represents a conventional stationary air-conditioning operation. A region 5 indicates an engine stop phase.

(9) A graph section 11 represents conventional braking due to generator operation. A graph section 12 represents a reverse rotation of the auxiliary units in a stationary air-conditioning operation 3 of the invention. Graph section 11 starts at a positive rotary speed 9. Positive rotary speed 9 may be an idle speed of the combustion engine.

(10) Graph section 12 starts at a negative rotary speed 10. Negative rotary speed 10 may be the negative idle speed. A graph section 13 represents the engine speed of the combustion engine. A double-headed arrow 15 indicates the time saved by the reverse rotation of the auxiliary units in a stationary air-conditioning operation 3 in accordance with the invention.

(11) Each of FIGS. 2 and 3 indicate three Cartesian coordinate diagrams 21, 22, and 23; and 31, 32, and 33, respectively, above one another. The x axis in each of coordinate diagrams 21, 22, 23, 31, 32, and 33 indicates the time in seconds. The y axis in each of coordinate diagrams 21 and 31 indicate a rotary speed at a suitable rotary speed unit, for instance times one thousand revolutions per minute. Graphs 24 and 34 indicate the progression of a rotary speed of a crankshaft pulley. Graphs 25 and 35 indicate the progression of a rotary speed of a combustion engine.

(12) The y axis in each of Cartesian coordinate diagrams 22 and 32 indicates torque in Newton meters. Graphs 26 and 36 indicate the progression of torque of a belt alternator starter. Graphs 27 and 37 indicate the progression of torque of an A/C compressor.

(13) The y axis in each of Cartesian coordinate diagrams 23 and 33 indicates torque in Newton meters. Graphs 28 and 38 indicate the torque progression of a pulley decoupler. Graphs 29 and 39 indicate the torque progression of a pawl freewheel. At region 30 of FIG. 3, it can be seen that the reverse rotation of the auxiliary units achieves a smooth response and a minimization of the starting time when the combustion engine is started.

(14) FIG. 4a is a highly simplified representation of coupling device 40 of the invention between crankshaft 41 and pulley 42. Coupling device 40 includes switchable pawl freewheel 81 in combination with form-fitting/positive clutch 82, which may advantageously be represented by freewheels that act in opposite directions. Combustion engine 43 is connected to crankshaft 41. Coupling device 40, in the form of, for example, decouplable accessory power take-off, further comprises air conditioning compressor 85 connected to pulley 42, and belt alternator starter 83 in the form of, for example, electric motor 86, connected to pulley 42.

(15) Pulley decoupler 44 is provided between crankshaft 41 and coupling device 40. Pulley decoupler 44 includes torsional vibration damper 47, which is embodied as an arc spring damper, for instance. Coupling device 40 is used to represent a switchable form-fitting or positive connection with a switchable freewheel.

(16) FIG. 4b represents rectangle 45 indicating normal operation of a switchable pawl freewheel. Rectangle 46 indicates stationary air-conditioning operation of the switchable pawl freewheel. The switchable pawl freewheel includes inner ring 48, which is connectable to a crankshaft so as to be fixed against relative rotation. A pulley decoupler may be provided between the crankshaft and the inner ring of the pawl freewheel. Inner ring 48 of the pawl freewheel is free to rotate relative to outer ring 49.

(17) Outer ring 49 of the pawl freewheel is connected for co-rotation to a belt of a belt drive by at least one belt track. Generator pawl 51 and boost pawl 52 are disposed between inner ring 48 and outer ring 49 of the pawl freewheel. Pawls 51 and 52 are movable/switchable between a freewheel position and a locking position.

(18) Pawls 51 and 52 are switched by switching device 54. Switching device 54 is embodied as a switching cage, for instance, including switching fingers 55 and 56. Switching finger 55 in switching device 54 is associated with generator pawl 51. Switching finger 56 of switching device 54 is associated with boost pawl 52.

(19) During normal operation 45, both generator pawl 51 and boost pawl 52 are in their locking positions, providing a positive, form-fitting connection between inner ring 48 and outer ring 49 of the pawl freewheel. In stationary air-conditioning operation 46, generator pawl 51 is folded in with the aid of switching device 54, in particular with the aid of switching finger 55.

(20) For stationary air-conditioning operation, outer ring 49 moves to the right in rectangle 46. This corresponds to a reversal of the direction of rotation of the belt drive. Boost pawl 56 is overrun in a freewheel-like way, i.e. boost pawl 52 does not transmit torque.

(21) To restart the combustion engine, the direction of rotation is reversed again. For restarting purposes, outer ring 49 moves to the left. Locking boost pawl 52 allows torque to be transmitted between outer ring 49 and inner ring 48. Generator pawl 51 may be coupled in at a later point with the aid of switching device 54. The two pawls 51 and 52 are, for example, pre-loaded into their locking positions, for instance by a spring device.

(22) FIG. 5 illustrates two Cartesian coordinate diagrams above one another. The upper coordinate diagram has an x axis 60 and a y axis 61. X axis 60 indicates a time in seconds. Y axis 61 indicates a rotary speed in revolutions per minute. Dashed line 62 indicates the progression of the rotary speed of the crankshaft. Dual line 63 indicates the progression of the rotary speed of the crankshaft. Dual line 63 indicates the progression of the rotary speed of the pulley.

(23) The lower coordinate diagram has an x axis 66 and a y axis 67. X axis 66 indicates the time in seconds. Y axis 67 indicates the position of the generator pawl (generator pawl 51 in FIG. 4b).

(24) Double-headed arrows 71 through 74 indicate different periods of time. The period of time indicated by double-headed arrow 71 represents a stationary air-conditioning operation. The period of time indicated by double-headed arrow 72 represents start preparations. The period of time indicated by double-headed arrow 73 represents an engine start, i.e. a combustion engine start. The period of time indicated by double-headed arrow 74 indicates a driving operation driven by the combustion engine.

(25) In the periods indicated by double-headed arrows 71 and 72, the rotary speed indicated by dashed line 62 of the crankshaft equals zero, i.e. the combustion engine is at a standstill. In a stationary air-conditioning operation indicated by double-headed arrow 71, the pulley rotates backwards. During the start preparation period indicated by double-headed arrow 72, the pulley is decelerated. Upon an engine start, which is indicated by double-headed arrow 73, the pulley and the crankshaft rotate forwards at the same rotary speed. In the periods indicated by double-headed arrows 71 through 73, generator pawl 68 is in its folded-in position. The generator pawl may be switched after the engine start, which is indicated by double-headed arrow 73, or a little later as indicated by the dashed line.

LIST OF REFERENCE NUMERALS

(26) 1 x axis 2 y axis 4 stationary air-conditioning operation 5 motor stop phase 11 graph section 12 graph section 13 graph section 15 double-headed arrow 21 diagram 22 diagram 23 diagram 24 graph 25 graph 26 graph 27 graph 28 graph 29 graph 30 region 31 diagram 32 diagram 33 diagram 34 graph 35 graph 36 graph 37 graph 38 graph 39 graph 40 coupling device 41 crankshaft 42 pulley 43 combustion engine 44 pulley decoupler 45 rectangle 46 rectangle 47 torsional vibration damper 48 inner ring 49 outer ring 51 generator pawl 52 boost pawl 54 switching device 55 switching finger 56 switching finger 60 x axis 61 y axis 62 dashed line 63 dual line 66 x axis 67 y axis 68 line 71 double-headed arrow 72 double-headed arrow 73 double-headed arrow 74 double-headed arrow 81 freewheel 82 positive clutch 83 belt alternator starter 84 decouplable accessory power take-off 85 air conditioning compressor 86 electric motor