MOTOR VEHICLE WITH INSERTABLE FOUR-WHEEL DRIVE

• US 20110087410A1
• Filed: 03/24/2006
• Published: 04/14/2011
• Est. Priority Date: 03/25/2005
• Status: Active Grant

• Current Assignee: Ferrari SPA (Stellantis NV)
• Original Assignee: Ferrari SPA (Stellantis NV)
• Inventors: Morawetz, Rudolf, Cimatti, Franco
• Granted Patent: US 8,364,360 B2
• Time in Patent Office: Days
• US Class Current: 701/60
• CPC Class Codes: B60K 17/35 including arrangements for suppressing or influencing the power transfer, e.g. viscous clutches differential gearing with locking devices F16H48/20
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: B60K 5/02 with the engine main axis, e.g. crankshaft axis, substantially in or parallel to the longitudinal centre line of the vehicle
• CPC Class Codes: B60W 2050/001 Proportional integral [PI] controller
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/106 Rate of change
• CPC Class Codes: B60W 2552/00 Input parameters relating to infrastructure
• CPC Class Codes: B60W 2710/027 Clutch torque
• CPC Class Codes: B60Y 2200/114 Racing vehicles, e.g. Formula one, Karts
• CPC Class Codes: Y10T 74/19116 Vehicle

Abstract

A motor vehicle with insertable four-wheel drive, including an engine having a crankshaft, a pair of main driving wheels constantly connected to the crankshaft by interposition of a gearbox provided with a first clutch, and a pair of secondary driving wheels, which may be connected to the crankshaft by an insertable transmission system. The insertable transmission system presents a second clutch, which is connected on one end with a fixed transmission ratio to the crankshaft upstream of the gearbox and on the other end with a fixed transmission ratio to the secondary driving wheels. A percentage of motive torque to be transmitted to the secondary driving wheels by the second clutch is determined according to dynamic parameters of the motor vehicle detected by respective sensors.

Claims

1-37. -37. (canceled)

38. An insertable four-wheel drive motor vehicle, comprising:

an engine presenting a crankshaft;

a pair of main driving wheels permanently connected to the crankshaft by interposition of a gearbox provided with at least one first clutch;

a pair of secondary driving wheels;

an insertable transmission system, which is adapted to connect the crankshaft also to the secondary driving wheels and comprises a second controllable clutch for transmitting a variable torque from zero to a maximum value;

the second clutch on one end is mechanically connected to the crankshaft upstream of the gearbox and on another end is mechanically connected to the secondary driving wheels;

an electronic control unit for controlling the insertable transmission system by controlling actuation of the second clutch; and

a number of first sensors, which are connected to the electronic control unit and detect a number of dynamic parameters of the motor vehicle,

wherein the electronic control unit determines a percentage of motive torque to be transmitted to the secondary driving wheels according to the dynamic parameters of the motor vehicle detected by the first sensors.

39. A motor vehicle according to claim 38, wherein the second clutch is connected on the one end with a first fixed transmission ratio to the crankshaft upstream of the gearbox and on the another end is connected with a second fixed transmission ratio to the second driving wheels.

40. A motor vehicle according to claim 38, wherein the gearbox comprises a plurality of gears;

the insertable transmission system comprising a gear chain, which presents a transmission ratio so that when a certain synchronism gear is engaged by the gearbox, the input and the output of the second clutch present a same speed.

41. A motor vehicle according to claim 38, wherein the dynamic parameters of the motor vehicle detected by the first sensors comprise longitudinal speed of the motor vehicle, longitudinal acceleration of the motor vehicle, and transversal acceleration of the motor vehicle.

42. A motor vehicle according to claim 38, wherein the electronic control unit activates the insertable transmission system to transfer motive torque to the secondary driving wheels through the second clutch only in drive conditions.

43. A motor vehicle according to claim 38, wherein the electronic control unit activates the insertable transmission system to transfer motive torque to the secondary driving wheels through the second clutch both in drive conditions and in coasting conditions.

44. A motor vehicle according to claim 38, wherein the electronic control unit determines the percentage of motive torque to be transmitted to the secondary driving wheels in closed loop by a first feedback control chain that uses average speed of rotation of the main driving wheels as a feedback variable.

45. A motor vehicle according to claim 44, wherein the first control chain determines a value of the reference speed of rotation of the main driving wheels according to a longitudinal speed of the motor vehicle.

46. A motor vehicle according to claim 44, wherein the first control chain comprises a proportioning-integrative regulator.

47. A motor vehicle according to claim 38, wherein the electronic control unit determines the percentage of motive torque to be transmitted to the secondary driving wheels by an open loop control chain.

48. A motor vehicle according to claim 47, wherein the second control chain comprises a first calculation block, which provides the percentage of motive torque to be transmitted to the secondary driving wheels according to dynamic parameters of the motor vehicle;

the first calculation block comprises a first memory, in which first maps are stored, which receives as an input the dynamic parameters of the motor vehicle and outputs a corresponding percentage of motive torque to be transmitted to the secondary driving wheels.

49. A motor vehicle according to claim 48, wherein the first memory of the first calculation block comprises a series of first maps, each of which is optimized for a respective grip condition.

50. A motor vehicle according to claim 38, wherein the electronic control unit determines the percentage of motive torque to be transmitted to the secondary driving wheels by an open loop control chain, which comprises a second calculation block that provides the percentage of motive torque to be transmitted to the secondary driving wheels according to a position of a control of an accelerator and according to a variation speed in time of the position of the accelerator control.

51. A motor vehicle according to claim 50, wherein the second calculation block comprises a second memory, in which second bi-dimensional maps are stored, which receives as an input a position of the accelerator control and the variation speed in time of the position of the accelerator control and outputs the percentage of motive torque to be transmitted to the secondary driving wheels.

52. A motor vehicle according to claim 50, wherein the second calculation block determines a null percentage of motive torque to be transmitted to the secondary driving wheels at low speed variations in time of the position of the accelerator control.

53. A motor vehicle according to claim 38, wherein the electronic control unit determines the percentage of motive torque to be transmitted to the secondary driving wheels by summing a first contribution and a second contribution;

the electronic control unit determines a first closed loop contribution by a first feedback control chain that uses an average speed of rotation of the main driving wheels as a feedback variable;

the electronic control unit determines the second contribution by a second open loop control chain.

54. A motor vehicle according to claim 53, wherein the first control chain determines a value of reference speed of rotation of the main driving wheels according to a longitudinal speed of the motor vehicle.

55. A motor vehicle according to claim 53, wherein the first control chain comprises a proportioning-integrative regulator.

56. A motor vehicle according to claim 53, wherein the second control chain comprises a first calculation block, which provides the percentage of motive torque to be transmitted to the secondary driving wheels according to dynamic parameters of the motor vehicle;

the first calculation block comprises a first memory, in which first maps are stored, which receives as an input the dynamic parameters of the motor vehicle and outputs a corresponding percentage of motive torque to be transmitted to the secondary driving wheels.

57. A motor vehicle according to claim 56, wherein the first memory of the first calculation block comprises a series of first maps, each of which is optimized for a respective grip condition.

58. A motor vehicle according to claim 38, wherein the electronic control unit determines the percentage of motive torque to be transmitted to the secondary driving wheels by summing a first contribution, a second contribution, and a third contribution;

the electronic control unit determines a first closed loop contribution by a first feedback control chain that uses an average speed of rotation of the main driving wheels as a feedback variable;

the electronic control unit determines the second contribution by a second open loop control chain;

the electronic control unit determines the third contribution by a third open loop control chain, which comprises a second calculation block that provides the percentage of motive torque to be transmitted to the secondary driving wheels according to a position of an accelerator control and according to a variation speed in time of the position of the accelerator control.

59. A motor vehicle according to claim 58, wherein the first control chain determines a value of the reference speed of rotation of the main driving wheels according to a longitudinal speed of the motor vehicle.

60. A motor vehicle according to claim 58, wherein the first control chain comprises a proportioning-integrative regulator.

61. A motor vehicle according to claim 58, wherein the second control chain comprises a first calculation block, which provides the percentage of motive torque to be transmitted to the secondary driving wheels according to dynamic parameters of the motor vehicle;

the first calculation block comprises a first memory, in which first maps are stored, which receives as an input the dynamic parameters of the motor vehicle and outputs a corresponding percentage of motive torque to be transmitted to the secondary driving wheels.

62. A motor vehicle according to claim 61, wherein the first memory of the first calculation block comprises a series of first maps, each of which is optimized for a respective grip condition.

63. A motor vehicle according to claim 58, wherein the second calculation block comprises a second memory, in which second bi-dimensional maps are stored, which receives as an input the position of the accelerator control and a variation speed in time of the position of the accelerator control and outputs the percentage of motive torque to be transmitted to the secondary driving wheels.

64. A motor vehicle according to claim 63, wherein the second calculation block determines a null percentage of motive torque to be transmitted to the secondary driving wheels at low speed variations in time of the position of the accelerator control.

65. A motor vehicle according to claim 38, wherein the second clutch is wet.

66. A motor vehicle according to claim 65, wherein the second clutch comprises a radiator for cooling oil.

67. A motor vehicle according to claim 66, wherein the radiator comprises a cooling device, which is operated to increase heat exchange carried out by the radiator and is controlled according to oil temperature.

68. A motor vehicle according to claim 65, wherein the second clutch comprises a temperature sensor, which detects the oil temperature of the second clutch;

the electronic control unit limits use of the second clutch according to the oil temperature in the second clutch itself.

69. A motor vehicle according to claim 65, wherein the electronic control unit does not use the second clutch if the oil temperature in the second clutch itself is higher than a determined threshold.

70. A motor vehicle according to claim 38, wherein the gearbox comprises a plurality of gears;

the insertable transmission system comprising a gear chain, which presents a transmission ratio so that when a synchronism gear is engaged by the gearbox input and the output of the second clutch present a same speed;

the electronic control unit comprising an interdiction block configured to prevent activation of the second clutch when the gear engaged by the gearbox is higher than the synchronism gear.

71. A motor vehicle according to claim 38, wherein the main driving wheels are rear wheels and the secondary driving wheels are front wheels.

72. A motor vehicle according to claim 71, wherein the engine is arranged in frontal position and is connected to the main driving wheels through a drive line comprising the first clutch and a first propeller shaft ending in the gearbox arranged on the rear axle;

in cascade to the gearbox a differential is connected, from which depart a pair of drive axles, each of which is integral with a respective rear driving wheel.

73. A motor vehicle according to claim 71, wherein the engine is arranged in a central position;

and the first clutch and the gearbox are arranged on a rear axle.

74. A motor vehicle according to claim 73, wherein the crankshaft is connected on one end to the first clutch to transmit motion to the main driving wheels and on another end is connected to the second clutch to transmit motion to the second driving wheels.