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EP-4741200-A1 - A HYBRID PROPULSION UNIT WITH TRANSMISSION AND A MOTORCYCLE COMPRISING THE PROPULSION UNIT

EP4741200A1EP 4741200 A1EP4741200 A1EP 4741200A1EP-4741200-A1

Abstract

The hybrid propulsion unit (13) according to the invention comprises an internal combustion engine (15); an electric motor/generator (41) and a transmission (19) to transmit power and torque to a drive wheel (3). A clutch (33) is also provided, adapted to cut off a power route between the internal combustion engine (15) and the input shaft (21) of the transmission (19), a well as a mechanical connection (31) from the output shaft (23) of the transmission (19) to the drive wheel (3). The electric motor/generator (41) and the input shaft (21) of the transmission (19) are connected to each other via a mechanical connection configured to transmit power between the electric motor/generator (41) and the input shaft (21) of the transmission (19) under any operating condition of the hybrid propulsion unit (13). A shift mechanism allows to mechanically couple an output of the clutch (33) to the input shaft (21) of the transmission (19) when the hybrid propulsion unit (13) operates in hybrid mode, and to mechanically decouple the output of the clutch (33) from the input shaft (21) of the transmission (19) when the hybrid propulsion unit (13) operates in electric mode. The shift mechanism is functionally coupled to a locking device (93) adapted to lock the transmission (19) in a fixed gear ratio when the hybrid propulsion unit (13) operates in electric mode.

Inventors

  • MARIOTTI, Walter

Assignees

  • Piaggio & C. S.P.A.

Dates

Publication Date
20260513
Application Date
20251110

Claims (14)

  1. A hybrid propulsion unit comprising: - an internal combustion engine; - an electric motor/generator; - a transmission (19) comprising an input shaft (21) adapted to receive power from the electric motor/generator (41) and the internal combustion engine (15), and an output shaft (23) adapted to transmit power to a drive wheel (3); - a clutch (33) adapted to cut off a power route between the internal combustion engine (15) and the input shaft (21) of the transmission (19); - a mechanical connection (31) from the output shaft (23) of the transmission (19) to the drive wheel (3); wherein the electric motor/generator (41) and the input shaft (21) of the transmission (19) are connected to each other via a mechanical connection configured to transmit power between the electric motor/generator (41) and the input shaft (21) of the transmission (19) under any operating condition of the hybrid propulsion unit (13); and wherein between the clutch (33) and the input shaft (21) of the transmission (19) a shift mechanism is provided, configured to: a. mechanically couple an output of the clutch (33) to the input shaft (21) of the transmission (19) when the hybrid propulsion unit (13) operates in hybrid mode; and b. mechanically decouple the output of the clutch (33) from the input shaft (21) of the transmission (19) when the hybrid propulsion unit (13) operates in electric mode. wherein the shift mechanism is functionally coupled to a locking device (93) adapted to lock the transmission (19) in a fixed gear ratio when the hybrid propulsion unit (13) operates in electric mode.
  2. The hybrid propulsion unit (13) of claim 1, wherein the shift mechanism comprises a gearwheel (37), supported idle on the input shaft (21) of the transmission (19), and an engaging member (38), torsionally coupled to the input shaft (21) of the transmission (19); and wherein the gearwheel (37) and the engaging member (38) are adapted to slide axially relative to each other along the input shaft (21) of the transmission (19), so as to be selectively torsionally coupled to, and decoupled from, each other.
  3. The hybrid propulsion unit (13) of claim 2, wherein the engaging member (38) is slidingly coupled to the input shaft (21) of the transmission (19) and functionally coupled to an actuator (63) that controls a sliding movement of the engaging member (38) along the input shaft (21) of the transmission (19).
  4. The hybrid propulsion unit (13) of claim 3, wherein the actuator (63) is connected to the engaging member (38) with the interposition of an elastic member (71, 73).
  5. The hybrid propulsion unit (13) of any of the preceding claims, wherein the locking device (93) is controlled by a control unit.
  6. The hybrid propulsion unit (13) of any of the preceding claims, wherein the transmission (19) is a manual transmission with a manual gear selector (91) of the transmission (19), and wherein the locking device (93) comprises a slider (94) that is mechanically coupled to the shift mechanism and adapted to take: - a lock position, where the slider (94) is engaged with the manual gear selector (91) of the transmission (19), thus preventing the movement thereof, when the hybrid propulsion unit (13) operates in electric mode; and - an unlock position, where the slider (94) is disengaged from the manual gear selector (91) of the transmission (19), thus allowing the motion thereof, when the hybrid propulsion unit (13) operates in hybrid mode.
  7. The hybrid propulsion unit (13) of claim 6, wherein the slider (94) is elastically stressed by an elastic member (95) toward the unlock position and is constrained to an actuator (65) adapted to cause the slider (94) to move toward the lock position.
  8. The hybrid propulsion unit (13) of claim 6 or 7, wherein the manual gear selector (91) comprises a hole (91.1), into which the slider (94) enters when in the lock position.
  9. The hybrid propulsion unit (13) of claim 6, 7 or 8, wherein the manual gear selector (91) comprises a pedal or a lever.
  10. The hybrid propulsion unit (13) of any of the preceding claims, comprising a gear train (47, 49, 51, 53) that connects the electric motor/generator (41) to the input shaft (21) of the transmission (19), wherein an end gear (53) of the gear train (47, 49, 51, 53) is torsionally coupled to the input shaft (21) of the transmission (19) so as to transmit motion from the electric motor/generator (41) to the input shaft (21) of the transmission (19).
  11. The hybrid propulsion unit (13) of claim 10, wherein an intermediate gear (51) of the gear train (47, 49, 51, 53) is supported idle on an output shaft (33.2) of the clutch (33).
  12. The hybrid propulsion unit (13) of any of the preceding claims, further comprising an electric starter motor (101) separate from the electric motor/generator (41).
  13. The hybrid propulsion unit (13) of any of the preceding claims, wherein the electric motor/generator (41) is electrically connected to an accumulator (43) to receive electric power from the accumulator when the motor/generator (41) operates in motor mode and to charge the accumulator (43) by supplying electric power thereto when the motor/generator (41) operates in generator mode.
  14. A motorcycle (1) comprising: a frame (9); at least one rear drive wheel (3); at least one front steering wheel (5); a saddle (11); the hybrid propulsion unit (13) of one or more of the preceding claims, wherein the output shaft (23) of the transmission (19) is mechanically connected to the rear drive wheel (3).

Description

TECHNICAL FIELD The present invention relates to improvements to the hybrid propulsion units, especially for motorcycles, i.e. saddle motor vehicles. BACKGROUND ART To mitigate environmental pollution caused by exhaust gas emissions from internal combustion engines, hybrid vehicles have been developed that combine at least one electric motor and at least one internal combustion engine to supply power to the drive wheel(s) of the vehicle. Typically, a control unit modulates the power supplied by the internal combustion engine and by the electric motor, based on the driving conditions that have been set and according to a program aiming at reducing the production of combustion gases. The electric motor is a reversible motor, which allows mechanical power to be converted into electrical power to recharge an accumulator. This occurs, for example, during braking, or when the vehicle is advancing downhill. A hybrid vehicle, specifically a hybrid motorcycle, is disclosed in EP3604013. This motorcycle comprises a transmission with a primary shaft, i.e. an input shaft, into which power is supplied from an internal combustion engine, and a secondary shaft, i.e. an output shaft, connected to the drive wheel of the motorcycle. Between the internal combustion engine and the primary shaft of the transmission a clutch is provided, which cuts off the power route between the internal combustion engine and the primary shaft, for example to allow gear shifting. The electric motor is connected to the secondary shaft of the transmission, i.e. the motion output shaft, via a gear train. The DE102019316617 discloses a hybrid transmission for a motor vehicle. US2020/0189566 discloses a hybrid transmission for a motorcycle. The current systems for transmitting torque and power from an arrangement comprising an internal combustion engine and an electric motor have some limitations, which it is desirable to overcome. SUMMARY OF THE INVENTION The present invention relates to a hybrid propulsion unit comprising: an internal combustion engine; an electric motor/generator; a transmission comprising an input shaft, adapted to receive power from the electric motor/generator and the internal combustion engine, and an output shaft, adapted to transmit power to a drive wheel; a clutch, adapted to cut off a power route between the internal combustion engine and the input shaft of the transmission; a mechanical connection from the output shaft of the transmission to the drive wheel. According to the invention, the electric motor/generator and the input shaft of the transmission are connected to each other via a mechanical connection configured to transmit power between the electric motor/generator and the input shaft of the transmission under any operating condition of the propulsion unit. Moreover, between the clutch and the input shaft of the transmission a shift mechanism is provided, configured to: (a) mechanically couple a clutch output to the input shaft of the transmission when the propulsion unit operates in hybrid mode; and (b) mechanically decouple the clutch output from the input shaft of the transmission when the propulsion unit operates in electric mode. In the following, the terms "electric motor," "electric motor/generator," and "electric machine" will be used interchangeably to indicate the same component of the propulsion unit, i.e. the machine that converts electric power to mechanical power supplied to the transmission of the propulsion unit. Essentially, according to the present invention, the electric machine, i.e. the electric motor, always meshes the input shaft of the transmission and always transmits torque and power to the input shaft of the transmission and, through the transmission, to the drive wheel, regardless of the selected operating mode: purely electric or hybrid mode. Conversely, the power, and thus the torque, generated by the heat engine, i.e. the internal combustion engine, is transmitted to the input shaft of the transmission only when the vehicle operates in hybrid mode. In purely electric mode, the shift mechanism mechanically separates the clutch output from the input shaft of the transmission, thereby isolating the internal combustion engine from the transmission and allowing operation in pure electric mode (i.e. with power and torque provided only by the electric motor). This configuration differs substantially from the prior art, for instance from the system disclosed in EP3604013, where the electric machine, i.e. the electric motor, supplies torque, and thus power, directly to the output shaft, i.e. the secondary shaft of the transmission, instead of to the primary shaft. Compared with this solution of the prior art, the hybrid propulsion unit of the present invention has significant advantages. In particular, if the motion of the electric motor is transmitted to the secondary shaft, i.e. the output shaft of the transmission, via a gear train, as disclosed in EP3604013, it is necessary for the propu