Hybrid powertrain

Abstract

A powertrain and controller for a hybrid power straddle-type vehicle 100 including an internal combustion engine 105 having a crankshaft. A first electric machine 104 is configured to drive the crankshaft. An input shaft 102 is drivingly connected to the crankshaft. A second electric machine 160 is drivingly connected to a drive shaft 171. A transmission 103 is configured to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios. A sliding input gear may be used in conjunction with at least on sliding input element or dogs.

Description

Field of the invention The present invention relates to a hybrid powertrain for a straddle-type vehicle. In particular, the present invention relates to a hybrid powertrain having two motors and an internal combustion engine. Background Hybrid electric vehicles include an internal combustion engine and at least one electric motor. They combine the instant torque, improved acceleration, and regenerative braking capabilities of the electric motor with the extended range and power output of the internal combustion engine. In straddle-type vehicles, such as motorcycles, space and weight constraints are greater compared to cars. This can make it challenging to integrate hybrid powertrains into straddle-type vehicles in view of the additional space needed for the electric motor, battery, and potentially complex transmission. United States Patent No. 11,607,945 discloses a hybrid vehicle having an engine, an electric motor, a power transmission shaft and a switching dog clutch slidable to cut off a power transmission route. Chinese Patent Publication No. 110329058A discloses a noclutch multi-gear dynamic coupling mechanism suitable for a plug-in hybrid electric vehicle, including an engine, first and second drive motors, multiple groups of gear pairs and four synchronisers. United States Patent No. 10,479,188 discloses a hybrid transmission for a motor vehicle including two concentric input shafts connected to a crankshaft of a heat engine and to an electric machine with no disconnect clutch. It is an aim of the present invention to provide an improved hybrid powertrain for straddle vehicles which addresses at least some of the above problems. Summary of the invention Embodiments of the disclosure aim to provide a powertrain for a hybrid power straddle type vehicle, the powertrain comprising any or all of the following features: an internal combustion engine comprising a crankshaft; a first electric machine configured to drive the crankshaft; an input shaft drivingly connected to the crankshaft; a second electric machine drivingly connected to a drive shaft; and a transmission configured to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios. This arrangement provides a P1 / P3 hybrid architecture for a motorcycle, for example, without requiring a clutch to disengage the engine from the input shaft of the transmission. This may provide the advantage of reducing the cost and mass of the motorcycle while providing more space available for the battery or the fuel tank, which can improve the range of the motorcycle. As used herein, the term ‘drivingly connected’ can be considered to mean that two components are permanently arranged such that rotation of one component causes rotation of the other component, and vice versa. This can be contrasted with two components being ‘drivingly connectable’, in which the components can be selectively configured to transfer rotational drive therebetween. The rotor of the first electric machine may be directly connected to the crankshaft. A direct connection may mean that there is no intermediary between the first electric machine and the crankshaft. This may further improve the packaging efficiency of the powertrain by omitting any transfer shaft between the first electric machine and the crankshaft. The powertrain may be a clutchless powertrain. The second electric machine may comprise a rotor drivingly connected to the drive shaft. The rotor may be drivingly connected to the drive shaft via a first gear pair. This may further improve the packaging of the transmission in the powertrain. The crankshaft, the input shaft and the drive shaft may be integrated within a crankcase. This may provide the advantage of housing the crankshaft and the shaft of the transmission into a single housing. The crankcase may comprise at least one opening. The at least one opening may be configured to receive at least one of: a piston shaft of the internal combustion engine; a rotational drive element of the first electric machine; and a rotational drive element of the second electric machine. This arrangement may allow components of the internal combustion engine and the electric machines to cooperate with the transmission. The crankshaft may be adjacent to at least one of the input shaft and the drive shaft. The crankshaft may be adjacent to at least one of the input shaft and the drive shaft in a direction perpendicular to the rotational axis of the crankshaft. Instead of prior arrangements in which the internal combustion engine is located in series with the transmission, this arrangement may provide the advantage of positioning the crankshaft and the other shafts in a parallel arrangement which may improve the compactness of the powertrain. The rotational axis of the crankshaft may be colinear with the rotational axis of the first electric machine. This may provide the advantage of having more efficient packaging and reducing the number of components in the powertrain. The rotational axes of the crankshaft, the input shaft and the drive shaft may be parallel to one another. The rotational axes may be provided in a triangular array. This may advantageously reduce the overall height of the transmission. The second electric machine may be drivingly connected to the drive shaft via an intermediate shaft. The intermediate shaft may be colinear with the input shaft. The intermediate shaft may be provided concentrically with the input shaft. The intermediate shaft may be drivingly connected to the drive shaft by a gear located at an opposite end of the intermediate shaft to the second electric machine. Since the second electric machine may have a relatively large diameter, this positioning may provide the advantage of reducing the extent to which the second electric machine protrudes out of the powertrain, thereby improving the packaging. The powertrain may further comprise a controller. The controller may be configured to effect movement of the transmission to a configuration in which rotational drive is transferred between the input shaft and the drive shaft at a first speed ratio of the plurality of speed ratios. This may be performed by controlling at least one of the first electric machine and the internal combustion engine to thereby control a rotational speed of the input shaft in correspondence with a rotational speed of the drive shaft. The transmission may comprise a sliding input element on the input shaft. The transmission may comprise a sliding drive element on the drive shaft. At least one of the sliding input element and the sliding drive element may comprise dogs on an axial surface thereof. The dogs may be configured for axial engagement with at least one gear on the respective shaft. This may advantageously provide a powertrain in which changing gear can be performed without using a synchroniser. The sliding input element may comprise a sliding input gear. The sliding input gear may be drivingly connected to the input shaft. The sliding input gear may be slidable along the input shaft for selectable engagement with at least one input gear. The at least one input gear may be drivingly connected to the drive shaft. The at least one input gear may comprise a first input gear and a second input gear. The sliding input gear may be slidable between: a first position in which the sliding input gear is engaged with the first input gear; a second position in which the sliding input gear is engaged with the second input gear; and a neutral position in which the sliding input gear is engaged neither the first input gear nor the second input gear. This may provide an arrangement which allows the sliding input gear to engage with a gear on each side. This may advantageously provide an increased number of available gears while being space efficient. The sliding drive element may comprise a sliding drive gear. The sliding drive gear may be drivingly connected to the drive shaft. The sliding drive gear may be slidable along the drive shaft for selectable engagement with at least one drive gear. The at least one drive gear may be drivingly connected to the input shaft. The at least one drive gear may comprise a first drive gear and a second drive gear. The sliding drive gear may be slidable between; a first position in which the sliding drive gear is engaged with the first drive gear; a second position in which the sliding drive gear is engaged with the second drive gear; and a neutral position in which the sliding drive gear is engaged with neither the first drive gear nor the second drive gear. This arrangement may allow the sliding drive gear to engage with a gear on each side and may advantageously provide an increased number of available gears while being space efficient. Embodiments of the disclosure also aim to provide a controller for a powertrain for a hybrid power straddle-type vehicle, the controller being configured to perform any or all of: control a power supplied to a first electric machine configured to drive an input shaft; control a power supplied to a second electric machine configured to drive a drive shaft; control a power output of an internal combustion engine configured to drive the input shaft; control a transmission to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios; and effect movement of the transmission to a configuration in which rotational drive is transferred between the input shaft and the drive shaft at a first speed ratio of the plurality of speed ratios, by controlling at least one of the first electric machine and the internal combustion engine to thereby control a rotational speed of the input shaft in correspondence with a rotational speed of the drive shaft. The controller may be configured to determine a charge level of a battery of the powertrain. The controller may be configured to control a power supplied to the first electric machine and / or the second electric machine based on the determined charge level. The controller may be configured to supply power from the battery to the second electric machine if the charge level is determined to be above a take-off threshold. This can provide advantageous functionality that checks that the battery is charged sufficiently before the motorcycle is permitted to take-off. The controller may be configured to start the internal combustion engine using the first electric machine. The controller may be configured to use the internal combustion engine to charge the battery if the charge level is determined to be below the take-off threshold. This can provide a functionality that charges the battery using the engine if the charge level is too low for take-off. The controller may be configured to discharge the battery by supplying power from the battery to the first electric machine if the charge level is determined to exceed a regenerative braking threshold. This can provide the advantageous behaviour that the controller can discharge the battery to accommodate regenerative braking, thereby increasing the energy efficiency of the powertrain. The controller may be configured to determine the regenerative braking threshold based on a calculation of a continuous maximum charge recuperation of the battery. This may provide a dynamic way of controlling the maximum allowed charge capacity of the battery to maximise the amount of regenerative braking, thereby improving energy efficiency. The continuous maximum charge recuperation of the battery may be determined based on a predicted navigational route of the straddle-type vehicle. This can allow the controller to customise the charge capacity of the battery based on a particular journey. For example, for a flat driving route, the battery may be allowed to charge a higher level if it is determined that the degree of regenerative braking will be relatively low. Embodiments of the disclosure also aim to provide a hybrid power straddle-type vehicle, the powertrain comprising any or all of the following features: an internal combustion engine configured to drive an input shaft, a first electric machine configured to drive the input shaft; a second electric machine configured to drive a drive shaft; a transmission configured to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios; and a controller; wherein the controller is configured to effect movement of the transmission to a configuration in which rotational drive is transferred between the input shaft and the drive shaft at a first speed ratio of the plurality of speed ratios, by controlling at least one of the first electric machine and the internal combustion engine to thereby control a rotational speed of the input shaft in correspondence with a rotational speed of the drive shaft. Embodiments of the disclosure also aim to provide a straddle-type vehicle comprising the powertrain and / or the controller as described herein above. Brief description of the drawings Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows a schematic diagram of a powertrain according to embodiments of the disclosure; Fig. 2 shows another schematic diagram of the powertrain of Figure 1; Fig. 3 shows a schematic diagram of the powertrain of Figures 1 and 2 with a transmission in a first configuration; Fig. 4 shows a schematic diagram of the powertrain of Figures 1 transmission in a second configuration; Fig. 5 shows a schematic diagram of the powertrain of Figures 1 transmission in a third configuration; Fig. 6 shows a schematic diagram of the powertrain of Figures 1 transmission in a fourth configuration; Fig. 7 shows a schematic diagram of the powertrain of Figures 1 and 2 with the and 2 with the and 2 with the and 2 with the transmission in a fifth configuration; Fig. 8 shows a schematic diagram of a crankcase for the powertrain of Figures 1 and 2. Detailed description of the drawings Embodiments of the disclosure relate to a powertrain for a straddle vehicle, such as a motorcycle. The disclosure is not limited to straddle-type vehicles, but may relate more generally to light motor vehicles (i.e. L-category vehicles), such as light two-wheel powered vehicles (including mopeds), three-wheel mopeds, two-wheel motorcycles, two-wheel motorcycles with sidecars, powered tricycles, light quadricycles and heavy quadricycles. The powertrain is for a hybrid electric vehicle adopting the P1 and P3 architecture, such that a first motor (P1) is connected to the engine and a second motor (P3) is connected to the drive shaft to drive the wheel. The engine and the first motor are arranged to drive an input shaft. The powertrain includes a transmission so that drive from the input shaft can be transferred to the drive shaft. The first motor and the second motor are both connected to a battery. The second motor can use power from the battery to drive the wheel and can provide regenerative braking capabilities to charge the battery by acting as a generator during braking of the vehicle. The first motor can act as a generator to charge the battery using rotational drive from the engine. In examples disclosed herein, the powertrain does not have a clutch to disengage the engine from the input shaft. Instead, the output of the engine is always transferred to the input shaft of the transmission. The transmission does not employ synchronisers to facilitate engaging of gears in the transmission. Instead, the transmission uses sliding elements, for example using dog couplings, to selectively engage gears for selection of different gear ratios. In some examples, the transmission has two sliding dogs, one provided on each of the input shaft and the drive shaft. Each sliding dog can slide between different positions to engage with a gear on either side thereof. If a sliding dog attempts to engage a gear that is travelling at a significantly different speed, then the engagement may cause damage to the transmission and noise. In order to provide a smoother engagement, a controller of the powertrain speeds up or slows down the input shaft so that the relative rotational speed between the engaging gears is reduced or eliminated. The controller achieves this by increasing or decreasing the power delivered to the first motor to thereby adjust the speed of rotation of its rotor. Instead, or in addition to this functionality, the controller may change the rotational speed of the input shaft by controlling the speed of the engine, for example by controlling the ignition and / or the degree of throttle opening. Figure 1 shows a schematic diagram of a powertrain 100 for a hybrid power straddle-type vehicle. The powertrain 100 comprises an internal combustion engine (ICE) configured to drive an input shaft 102. The powertrain 100 also comprises a first electric machine 104 configured to drive the input shaft 102 and a second electric machine 160 configured to drive a drive shaft 171. The powertrain 100 further comprises a transmission 103 configured to transfer rotational drive between the input shaft 102 and the drive shaft 171 at a plurality of speed ratios. A controller 180 of the powertrain 100 is configured to effect movement of the transmission 103 to a configuration in which rotational drive is transferred between the input shaft 102 and the drive shaft 171 at a first speed ratio of the plurality of speed ratios, by controlling at least one of the first electric machine 104 and the ICE 105 to thereby control a rotational speed of the input shaft 102 in correspondence with a rotational speed of the drive shaft 171. The powertrain 100 provides a P1 / P3 hybrid drive architecture. In particular, the first electric machine 104 provides the P1 motor / generator and the second electric machine 160 provides the P3 motor / generator. In this respect, the powertrain 100 further comprises a battery 165 electrically connected to the first electric machine 104 and the second electric machine 160. The first electric machine 104 can be configured to drive the input shaft 102 by being drivingly connected thereto. Being drivingly connected to the input shaft 102 means that rotation of the first electric machine 104 (in particular, a rotor thereof) causes rotation of the input shaft 102, and vice versa. It will be appreciated that the two components need not be directly connected to one another in order to achieve such rotation. The ICE 105 can be configured to drive the input shaft 102 by the action of reciprocating pistons (not shown) on a crankshaft. As such, both the first electric machine 104 and the ICE 105 are configured to drive and be driven by the input shaft 102. In view of this, the first electric machine 104 can be configured as an integrated starter-generator (ISG)for the ICE 105. The second electric machine 160 can be configured to drive the drive shaft 171 by being drivingly connected thereto. Being drivingly connected to the drive shaft 171 means that rotation of the second electric machine 160 (in particular, a rotor thereof) causes rotation of the drive shaft 171, and vice versa. Again, such components need not be directly connected to achieve this rotation but may be connected via one or more gear pairs. The drive shaft 171 is configured to transfer rotational drive between the powertrain 100 and a wheel 175 of the straddle-type vehicle. As such, the second electric machine 160 can be considered a tractive motor. The transmission 103 can transfer rotational drive between the input shaft 102 and the drive shaft 171 using a plurality of gears, each being drivingly connected to either the input shaft 102 or the drive shaft 171. In this respect, the transmission 103 has a number of configurations in order to select whether, or the extent to which, rotational drive is transferred between the input shaft 102 and the drive shaft 171. In a neutral configuration, the transmission 103 prevents rotational drive being transferred. In another configuration, the transmission 103 permits rotational drive to be transferred at a first speed ratio. This may be facilitated by a first gear drivingly connected to the input shaft 102 being engaged with a second gear drivingly connected to the drive shaft 171. In other configurations, the transmission 103 permits rotational drive to be transferred at other speed ratios different from the first speed ratio. The transmission 103 can be controlled by the controller 180 to shift between the different configurations. The powertrain 100 is a clutchless powertrain in that there is no clutch mechanism to selectively disengage the ICE 105 from the input shaft 102. For example, the powertrain 100 may be arranged such that rotational drive transfer between the input shaft 102 and the ICE 105 is uninterruptable. Furthermore, the powertrain 100 does not employ synchronisers in the transmission 103 to assist with changing gears. Instead, in order to engage the first gear with the second gear, for example, the controller 180 is configured to match the speeds of the first gear and the second gear by controlling the speed of the input shaft 102 via the first electric machine 104. In one scenario, if the first gear is rotating at a rotational speed that is slower than that of the second gear, then the controller can supply the first electric machine 104 with more power such that it provides more rotational drive to the input shaft 102, thereby speeding up the input shaft to a speed that corresponds with that of the drive shaft 171. A corresponding speed does not necessarily require that the speed of the input shaft 102 is the same or similar to the speed of the drive shaft 171. Rather, the controller 180 controls the speed of the input shaft 102 such that the engaging gears have a matching or near-matching rotational speed (i.e., revolutions per minute). The powertrain 100 can facilitate several modes of operation in a hybrid straddle-type vehicle. In an electric vehicle (EV) mode, the second electric machine 160 can use power from the battery 165 to drive the wheel 175 via the drive shaft 171. This mode may be particularly suitable for vehicle take-off (i.e. accelerating from zero speed) and for low-speed driving. Meanwhile, the ICE 105 can be used to drive the input shaft 102 to thereby charge the battery 165 via the first electric machine 104 acting as a generator. As such, this mode does not require any rotational drive to be transferred between the drive shaft 171 and the input shaft 102, such that the transmission 103 can be in the neutral configuration. In a hybrid mode, the second electric machine 160 can continue to drive the drive shaft 171, using power from the battery 165, while being supplemented by torque provided by the ICE 105. This mode may be particularly suitable for vehicle acceleration at higher speeds. In this mode, the transmission 103 is controlled to transfer rotational drive from the input shaft 102 to the drive shaft 171. Meanwhile, the first electric machine 104 can be operated in generator mode to charge the battery 165 through the rotational drive of the input shaft 102. In a stationary charge mode, the ICE 105 can provide rotational drive to the input shaft 102 in order to charge the battery 165 via the first electric machine 104 operating in generator mode. In this mode, the transmission 103 can be in the neutral configuration to prevent any rotational drive being transferred to the drive shaft 171 during charging. This mode may be particularly suitable for low battery situations in which there is enough battery to start the ICE 105 using the first electric machine 104 as a starter motor, but not enough battery to sustain driving in the EV mode. In an ICE mode, the ICE 105 can provide rotational drive to the wheel 175 via the input shaft 102 and the drive shaft 171. In this mode, the transmission 103 is in a connected configuration and the second electric machine 160 does not operate, such that the vehicle is driven solely by the ICE 105. The controller 180 may be configured to determine a charge level of the battery 165. As such, the controller 180 can be configured to control a power supplied to the first electric machine 104 and / or the second electric machine 160 based on the determined charge level. For example, the controller 180 may determine that the charge level is above a takeoff threshold, such that it can supply power to the second electric machine 160 to provide torque to the wheel 175. In another example, the controller 180 may determine that the charge level is below the take-off threshold, such that the battery 165 cannot supply sufficient power to the second electric machine 160 for take-off. In this situation, the controller 180 may be configured to start the ICE 105 using the first electric machine 104 as a starter motor, and to subsequently use the ICE 105 to charge the battery 165 by using the first electric machine 104 as a generator until the charge level is sufficient for take-off using the second electric machine 160. In some circumstances, the charge level of the battery 165 may be too high to accommodate regenerative braking. If the charge level is determined to exceed a regenerative braking threshold, then the controller 180 may discharge the battery 165 by supplying power from the battery 165 to the first electric machine 104. The regenerative braking threshold may be determined based on a calculation of a continuous maximum charge recuperation of the battery 165. In other words, the controller 180 may determine the maximum charge recuperation from a single braking event and use that to influence the regenerative braking threshold. The continuous maximum charge recuperation may be determined based on a predicted navigational route of the vehicle. For example, if the controller 180 determines that the vehicle is likely to encounter a large downslope which would require significant braking, then the regenerative braking threshold can be lowered in order to accommodate the charge recuperation during the downslope. Figure 2 is a schematic diagram showing additional detail of the powertrain 100 described in relation to Figure 1. The ICE 105 is not shown in Figure 2 but is schematically represented by a crankshaft 101. In addition to the crankshaft 101 being driven by the reciprocating action of the pistons of the ICE 105, the first electric machine 104 is also configured to drive the crankshaft 101. In this respect, the first electric machine 104 (in particular, a rotor thereof) is drivingly connected to the crankshaft 101. The first electric machine 104 may be directly connected to, or form an integral part of, the crankshaft 101. The crankshaft 101 is drivingly connected to the input shaft 102 via a primary drive 109. For example, the crankshaft 101 may be connected to the input shaft 102 via a gear pair provided by the primary drive 109. The crankshaft 101 has an axis of rotation that is parallel to that of the input shaft 102. The second electric machine 160 may be configured to drive an intermediate shaft 161. In this arrangement, the second electric machine 160 (in particular, a rotor thereof) is drivingly connected to the intermediate shaft 161. The second electric machine 160 may be directly connected to, or form an integral part of, the intermediate shaft 161. The intermediate shaft 161 has an axis of rotation that is parallel to the axes of rotation of the crankshaft 101 and the input shaft 102. At least part of the intermediate shaft 161 is concentrically received by the input shaft 102. As such, the rotation axes of the intermediate shaft 161 and the input shaft 102 are colinear. In the example shown, the first electric machine 160 is positioned at a first axial end of the input shaft 102 and the intermediate shaft 161 extends through the input shaft 102 and exits a second axial end thereof. As mentioned above, the drive shaft 171 is drivingly connected to the wheel 175. In the arrangement shown, the connection is provided by a chain drive 173. The chain drive 173 is connected between a transmission sprocket 172 and a wheel sprocket 174 to transfer rotational drive therebetween. The transmission sprocket 172 is drivingly connected to, or an integral part of, the drive shaft 171. The transmission 103 comprises a plurality of gear pairs. In the arrangement shown, the transmission 103 comprises five gear pairs. A first gear pair 110 is configured to transfer rotational drive from the intermediate shaft 161 to the drive shaft 171, such that the second electric machine 160 can be drivingly connected to the drive shaft 171. A second gear pair 120 is configured to selectively transfer rotational drive from the input shaft 102 to the drive shaft 171, depending on the configuration of the transmission 103. The second gear pair 120 comprises an input gear provided around the input shaft 102 and a drive gear provided around the drive shaft. The third gear pair 130, fourth gear pair 140 and fifth gear pair 150 may be arranged in a similar manner to the second gear pair 120, except that the gear ratio between the drive gear and the input gear decreases for each successive gear pair. Figure 3 is a schematic diagram of the powertrain 100 showing a detailed example of a transmission 103. Similarly to Figure 2, the powertrain 100 is configured such that the first electric machine 104 and the ICE (not shown) are configured to drive the input shaft 102, which may be via a crankshaft 101 and a primary drive 109. The second electric machine 160 is configured to drive the drive shaft 171 via the intermediate shaft 161, and the drive shaft 171 is drivingly connected to the final drive or transmission sprocket 172. In the arrangement shown, the input shaft 102 sleeves the intermediate shaft 161. The transmission 103 comprises five gear pairs. As also described in relation to Figure 2, the first gear pair 110 may be provided at an opposite end of the intermediate shaft 161 to the second electric machine 160. In alternative arrangements, the first gear pair 110 may be provided adjacent the second electric machine 160, for example between the second electric machine 160 and the primary drive 109. The first gear pair 110 drivingly connects the second electric machine 160 to the drive shaft 171. In this way, the second electric machine 160 is permanently connected to the drive shaft 171 such that a rotational drive or torque provided by the second electric machine 160 will always be transferred to the drive shaft 171 and, likewise, a rotational drive or torque provided by the drive shaft 171 will always be transferred to the second electric machine 160. The first gear pair 110 may comprise a first input gear 111 and a first drive gear 115. The first input gear 111 is fixed to the intermediate shaft 161 so as to rotate therewith. In other arrangements, the first input gear 111 may be an integral part of the intermediate shaft 161 in that the first input gear 111 may be provided by a plurality of teeth extending radially from the intermediate shaft 161. This applies to any gear described as being fixed to a shaft. The first drive gear 115 is fixed to the drive shaft 161 so as to rotate therewith. The first drive gear 115 is drivingly connected to the first input gear 111, for example by being meshed with the first input gear 111 such that torque is transferred therebetween. The second gear pair 120 may be provided at a proximal end of the input shaft 102 and the drive shaft 171, which may be the end closest to the second electric machine 160. In the arrangement shown, the second gear pair 120 is arranged such that the primary drive 109 is axially between the second gear pair 120 and the second electric machine 160. The second gear pair 120 may comprise a second input gear 121 and a second drive gear 125. The second input gear 121 is fixed to the input shaft 102 so as to rotate therewith. The second drive gear 125 is rotatably connected to the drive shaft 171 such that the second drive gear 125 can rotate independently of the drive shaft 171. The second drive gear 125 is mounted on the drive shaft 171 at a fixed axial position therealong. The second drive gear 125 is drivingly connected to the second input gear 121, for example by being meshed with the second input gear 121 such that torque is transferred therebetween. The third gear pair 130 may be provided adjacent the second gear pair 120. In particular, the third gear pair 130 may be provided between the second gear pair 120 and the fifth gear pair 150. The third gear pair 130 may comprise a third input gear 131 and a sliding drive gear 135, which may be a sliding dog. The third input gear 131 is rotatably connected to the input shaft 102 such that the third input gear 131 can rotate independently of the input shaft 102. The third input gear 131 is mounted on the input shaft 102 at a fixed axial position therealong. The sliding drive gear 135 is mounted on the drive shaft 171 so as to rotate therewith and be slidable therealong. In this way, while the third input gear 131 has a fixed axial position along the input shaft 102, the sliding drive gear 135 can slide relative to the drive shaft 171 and the third input gear 131. The sliding drive gear 135 is configured to slide in a first direction towards the second gear pair 120 and in a second direction towards the fifth gear pair 150, as will be explained in more detail in relation to Figures 4 and 7. The sliding drive gear 135 is drivingly connected to the third input gear 131, for example by being meshed with the third input gear 131 such that torque is transferred therebetween. The fourth gear pair 140 may be provided adjacent the first gear pair 110. In particular, the fourth gear pair 140 may be provided at a distal end of the input shaft 102, between the first gear pair 110 and the fifth gear pair 150. The fourth gear pair 140 may comprise a fourth input gear 141 and a fourth drive gear 145. In the illustrated example, the fourth input gear 141 is rotatably connected to the input shaft 102 such that the fourth input gear 141 can rotate independently of the input shaft 102. The fourth input gear 141 is mounted on the input shaft 102 at a fixed axial position therealong. The fourth drive gear 145 is fixed to the drive shaft 171 so as to rotate therewith. The fourth drive gear 145 is drivingly connected to the fourth input gear 141, for example by being meshed with the fourth input gear 141 such that torque is transferred therebetween. The fifth gear pair 150 may be provided between the third gear pair 130 and the fourth gear pair 140. The fifth gear pair 150 may comprise a fifth drive gear 155 and a sliding input gear 151, which may be a sliding dog. The fifth drive gear 155 is rotatably connected to the drive shaft 171 such that the fifth drive gear 155 can rotate independently of the drive shaft 171. The fifth drive gear 155 is mounted on the drive shaft 171 at a fixed axial position therealong. The sliding input gear 151 is mounted on the input shaft 102 so as to rotate therewith and be slidable therealong. In this way, while the fifth drive gear 155 has a fixed axial position along the drive shaft 171, the sliding input gear 151 can slide relative to the input shaft 102 and the fifth drive gear 155. The sliding input gear 151 is configured to slide in a first direction towards the third gear pair 130 and in a second direction towards the fourth gear pair 140, as will be explained in more detail in relation to Figures 5 and 6. The sliding input gear 151 is drivingly connected to the fifth drive gear 155, for example by being meshed with the fifth drive gear 155 such that torque is transferred therebetween. Figure 3 illustrates a first configuration of the transmission 103 in which no rotational drive is transferred between the input shaft 102 and the drive shaft 171. In operation, assuming the primary drive 109 is being driven by the ICE 105, the second input gear 121 and the second drive gear 125 will by driven by the input shaft 102. Since the second drive gear 125 is not drivingly connected to the drive shaft 171, no torque is transferred thereto. Likewise, the sliding input gear 151 and the fifth drive gear 155 rotate with the input shaft 102, but no torque is transferred to the drive shaft 171 because the fifth drive gear 155 is not drivingly connected to the drive shaft 171. For the third gear pair 130, the third input gear 131 is not drivingly connected to the input shaft 102 such that no torque is transferred between the input shaft 102 and the third input gear 131. Similarly, for the fourth gear pair 140, the fourth input gear 141 is not drivingly connected to the input shaft 102 such that no torque is transferred between the input shaft 102 and the fourth input gear 141. In this first configuration, torque can be transferred between the second electric machine 160 and the drive shaft 171 via the first gear pair 110. As such, the second electric machine 160 can provide motive power to the transmission sprocket 172 in an EV driving mode. In a regenerative braking mode, rotational drive from the wheel 175 via the transmission sprocket 172 is transferred to the second electric machine 160 via the first gear pair 110 to charge the battery by the second electric machine 160 acting as a generator. Figure 4 illustrates a second configuration of the transmission 103. As described above, the sliding drive gear 135 can slide in a first direction (indicated by the arrows) toward the second gear pair 120, more specifically toward the second drive gear 125. The sliding drive gear 135 is configured to engage with the second drive gear 125 so as to rotate at the same rotational speed as the second drive gear 125. In this way, the sliding drive gear 135 is drivingly connectable to the second drive gear 125 such that, when engaged, torque can be transferred between the sliding drive gear 135 and the second drive gear 125. Such an engagement between adjacent gears may be provided by any means suitable for transferring torque between axially opposing gears. In the arrangements described herein, the engagement is provided by a dog coupling. In this respect, the second drive gear 125 comprises second drive gear dogs 126 and the sliding drive gear 135 comprises first sliding drive dogs 136. The second drive gear dogs 126 and the first sliding drive dogs 136 are provided on their respective gears as a distribution of axial protrusions and recesses around the rotational axis of the drive shaft 171. The transmission 103 is arranged such that the second drive gear dogs 126 and the first sliding drive dogs 136 face each other. In this way, when the sliding drive gear 135 is moved toward the second gear pair 120, the second drive gear dogs 126 and the first sliding drive dogs 136 engage with each other such that torque is transferred between the sliding drive gear 135 and the second drive gear 125. As such, rotational drive can be transferred between the input shaft 102 and the drive shaft 171 via the second gear pair 120 and the sliding drive gear 135. Figure 5 illustrates a third configuration of the transmission 103. As described above, the sliding input gear 151 can slide in a first direction (indicated by the arrows) toward the third gear pair 130, more specifically toward the third input gear 131. The sliding input gear 151 is configured to engage with the third input gear 131 so as to rotate at the same rotational speed as the third input gear 131. In this way, the sliding input gear 151 is drivingly connectable to the third input gear 131 such that, when engaged, torque can be transferred between the sliding input gear 151 and the third input gear 131. The engagement may be provided by a dog coupling. In the arrangement shown, the third input gear 131 comprises third input gear dogs 132 and the sliding input gear 151 comprises first sliding input dogs 152. The third input gear dogs 132 and the first sliding input dogs 152 are provided on their respective gears as a distribution of axial protrusions and recesses around the rotational axis of the input shaft 102. The transmission 103 is arranged such that the third input gear dogs 132 and the first sliding input dogs 152 face each other. In this way, when the sliding input gear 151 is moved toward the third gear pair 130, the third input gear dogs 132 and the first sliding input dogs 152 engage with each other such that torque is transferred between the sliding input gear 151 and the third input gear 131. As such, rotational drive can be transferred between the input shaft 102 and the drive shaft 171 via the third gear pair 130 and the sliding input gear 151. Figure 6 illustrates a fourth configuration of the transmission 103. As described above, the sliding input gear 151 can slide in a second direction (indicated by the arrows) toward the fourth gear pair 140, more specifically toward the fourth input gear 141. The sliding input gear 151 is configured to engage with the fourth input gear 141 so as to rotate at the same rotational speed as the fourth input gear 141. In this way, the sliding input gear 151 is drivingly connectable to the fourth input gear 141 such that, when engaged, torque can be transferred between the sliding input gear 151 and the fourth input gear 141. The engagement may be provided by a dog coupling. In the arrangement shown, the fourth input gear 141 comprises fourth input gear dogs 142 and the sliding input gear 151 comprises second sliding input dogs 153. The fourth input gear dogs 142 and the second sliding input dogs 153 are provided on their respective gears as a distribution of axial protrusions and recesses around the rotational axis of the input shaft 102. The transmission 103 is arranged such that the fourth input gear dogs 142 and the second sliding input dogs 153 face each other. In this way, when the sliding input gear 151 is moved toward the fourth gear pair 140, the fourth input gear dogs 142 and the second sliding input dogs 153 engage with each other such that torque is transferred between the sliding input gear 151 and the fourth input gear 141. As such, rotational drive can be transferred between the input shaft 102 and the drive shaft 171 via the fourth gear pair 140 and the sliding input gear 151. Figure 7 illustrates a fifth configuration of the transmission 103. As described above, the sliding drive gear 135 can slide in a second direction (indicated by the arrows) toward the fifth gear pair 150, more specifically toward the fifth drive gear 155. The sliding drive gear 135 is configured to engage with the fifth drive gear 155 so as to rotate at the same rotational speed as the fifth drive gear 155. In this way, the sliding drive gear 135 is drivingly connectable to the fifth drive gear 155 such that, when engaged, torque can be transferred between the sliding drive gear 135 and the fifth drive gear 155. The engagement may be provided by a dog coupling. In the arrangement shown, the fifth drive gear 155 comprises fifth drive gear dogs 156 and the sliding drive gear 135 comprises second sliding drive dogs 137. The fifth drive gear dogs 156 and the second sliding drive dogs 137 are provided on their respective gears as a distribution of axial protrusions and recesses around the rotational axis of the input shaft 102. The transmission 103 is arranged such that the fifth drive gear dogs 156 and the second sliding drive dogs 137 face each other. In this way, when the sliding drive gear 135 is moved toward the fifth gear pair 150, the fifth drive gear dogs 156 and the second sliding drive dogs 137 engage with each other such that torque is transferred between the sliding drive gear 135 and the fifth drive gear 155. As such, rotational drive can be transferred between the input shaft 102 and the drive shaft 171 via the fifth gear pair 150 and the sliding drive gear 135. With reference to Figures 3 to 7, the transmission 103 overall comprises five gear pairs including two sliding gears. The first gear pair 110 drivingly connects the second electric machine 160 to the drive shaft 171. The input shaft 102 is drivingly connectable with the drive shaft 171 by one of the remaining gear pairs and a sliding gear, such as the sliding input gear 151 or the sliding drive gear 135. The sliding input gear 151 is slidable along the input shaft 102 for selectable engagement with the third input gear 131 and the fourth input gear 141. In this respect, the sliding input gear 151 has a first position in which it is engaged with the third input gear 131, which is drivingly connected to the drive shaft 171 via the sliding drive gear 135, and a second position in which the sliding input gear 151 is engaged with the fourth input gear 141, which is drivingly connected to the drive shaft 171 via the fourth drive gear 145. The sliding input gear 151 also has a neutral position in which it is engaged with neither the third input gear 131 nor the fourth input gear 141. The sliding drive gear 135 is slidable along the drive shaft 171 for selectable engagement with the second drive gear 125 and the fifth drive gear 155. In this respect, the sliding drive gear 135 has a first position in which it is engaged with the second drive gear 125, which is drivingly connected to the input shaft 102 via the second input gear 121, and a second position in which the sliding drive gear 135 is engaged with the fifth drive gear 155, which is drivingly connected to the input shaft 102 via the sliding input gear 151. The sliding drive gear 135 also has a neutral position in which it is engaged with neither the second drive gear 125 nor the fifth drive gear 155. The transmission 103 may employ a sequential transmission system. This means that the transmission 103 may be configured to only allow selection of the next gear or the previous gear in the sequence of gears. For example, in the first gear, the transmission may only allow shifting to the second gear. In the second gear, the transmission may only allow shifting to the first gear or to the third gear, and so on. In some arrangements, the movement of the sliding input gear 151 and the sliding drive gear 135 may be governed by a shift drum mechanism (not shown) of the transmission. Such a shift drum mechanism could comprise a selector drum having two tracks (one for each of the sliding gears 151, 135) that can direct the path of selector forks connected to each of the sliding gears 151, 135 in order to control their position along their respective shaft. The controller 180 is configured to control the rotation of the shift drum to select gears as required. The controller 180 may actuate rotation of the shift drum automatically and / or in response to a command by the driver, such as by a button on the handlebar of the straddle-type vehicle. The operation of the powertrain 100 for an accelerating vehicle will now be described. Starting from the vehicle being stationary, take-off is performed using the second electric machine 160 as a tractive motor, while the sliding gears remain in their neutral positions. In order to provide additional torque from the primary drive 109 at higher speeds, the transmission 103 is shifted into the second configuration by moving the sliding drive gear 135 into engagement with the second drive gear 125, to facilitate torque transfer from the input shaft 102 to the drive shaft 171 via the second gear pair 120. Before shifting, the sliding drive gear 135 may have a significantly different rotational speed to the second drive gear 125, such that engagement may cause damage or unwanted noise. In order to match the rotational speed of the sliding drive gear 135 to the second drive gear 125, the controller 180 controls the torque output of the first electric machine 104 to control the speed of the second drive gear 125 in correspondence with the speed of the sliding drive gear 135. The controller 180 can determine the rotational speed of the sliding drive gear 135 based on the rotational speed of the drive shaft 171, and likewise the controller 180 can determine the rotational speed of the second drive gear 125 based on the rotational speed of the input shaft 102 or the crankshaft 101. Therefore, in general, the controller 180 controls the torque provided by the first electric machine 104 to control a rotational speed of the input shaft 102 in correspondence with a rotational speed of the drive shaft 171. It will be appreciated that gear shifting to the third, fourth and fifth configurations can be achieved in a corresponding manner. The controller 180 can also be configured to facilitate appropriate gear shifting during a hard braking event. For example, if the transmission is in the fifth configuration (Figure 7) during a hard braking event, the controller 180 can be configured to move the transmission 103 to a neutral position by moving the sliding drive gear 135 away from the fifth drive gear 155, so that the ICE 105 is disconnected from the drive shaft 171. The drive shaft 171 can continue to drive the second electric machine 160 for regenerative braking. The controller 180 may switch off the ICE 105 and shift the gears in the following pattern: neutral to fourth to neutral to third to neutral to second to neutral. In each case, the first electric machine 104 can be used to synchronise the speeds of the input shaft 102 with that of the drive shaft 171 before axially-facing gears are engaged. Once the hard braking is finished, the vehicle can then be driven in the first configuration using the second electric machine 160, and then shifting up can be performed in the usual manner as described above. The downshifting described above can also be finalised when the vehicle is stopped. The first electric machine 104 can slightly rotate with the input shaft 102 to allow engagement of the dog couplings. This rotation can be done with very low torque to prevent moving the wheels via the drive shaft 171. Figure 8 shows a crankcase 106 of the powertrain 100. The crankcase 106 provides a housing for the crankshaft 101, the input shaft 102 and the drive shaft 171. In this way, the crankcase 106 contains both the crankshaft 101 of the ICE 105 and the transmission. The crankcase 106 may be formed of a single integral material, such as a single casting, or may be formed of two or more components which may each be a single casting and which may be connected together via studs, screws or similar fastening means. In the arrangement shown, the transmission includes the intermediate shaft 161, which is also housed within the crankcase 106. As shown in Figure 8, the ICE 105 may be at least partially received in the crankcase 106. In particular, the crankcase 106 may comprise at least one opening configured to receive at least one piston of the ICE 105, in order to facilitate connection of the at least one piston with the crankshaft 101 in the crankcase 106. The crankcase 106 may at least partially receive the first electric machine 104. For example, the crankcase 106 may comprise an opening configured to receive a rotational drive element of the first electric machine 104 for connection with the crankshaft 101. The crankcase 106 may at least partially receive the second electric machine 160. In particular, the crankcase 106 may comprise an opening configured to receive a rotational drive element of the second electric machine 160 for connection with the drive shaft 171, for example via the intermediate shaft 161. In each case, the rotational drive element may be a rotor of the respective electric machine or may be a component drivingly connected to the rotor. The powertrain 100 may be arranged such that the first electric machine 104 is on an opposite side of the crankcase 106 to the second electric machine 160. Furthermore, the ICE 105 may be arranged on an opposite side of the crankcase 106 to the drive shaft 171. The crankshaft 101, the input shaft 102 and the drive shaft 171 may be arranged such that their rotational axes occupy a triangular array. As shown in Figure 8, the rotational axes of these shafts (including the intermediate shaft 161 which is coaxial with the input shaft 102) are arranged in the crankcase 106 such that their rotational axes lie on separate vertices of a notional triangle 107, the triangle 107 being normal to the rotational axes. The crankshaft 101, the input shaft 102, the drive shaft 171 and, optionally, the intermediate shaft 161 may be arranged in a parallel manner. In the arrangement shown, the crankshaft 101 is arranged such that its rotational axis is parallel to and spaced apart from the rotational axes of the input shaft 102, the drive shaft 171 and the intermediate shaft 161. The crankshaft 101 may be spaced apart from such shafts in a direction that is perpendicular to the rotational axis thereof. The drive shaft 171 is arranged such that its rotational axis is parallel to and spaced apart (for example, in the perpendicular direction) from the crankshaft 101, the input shaft 102 and the intermediate shaft 161. As such, in the arrangement shown, the crankshaft 101 does not share a common rotational axis with any of the shafts of the transmission, such as the input shaft 102 and the drive shaft 171. While the transmission has been described in relation to Figures 3 to 7 as comprising a sliding input gear 151 and a sliding drive gear 135, an alternative arrangement (not shown) may instead employ sliding dog rings. In such an arrangement, at least one of the input shaft 102 and the drive shaft 171 may comprise a sliding element configured to slide between a first gear and a second gear on the respective shaft, to selectively engage with the first gear or the second gear. The sliding element may be a dog ring which does not have gear teeth, and the first and second gears may both rotate independently on the respective shaft, for example by being sleeved on the respective shaft. The above arrangement can be envisaged with reference to Figure 3. Instead of the sliding input gear 151 being drivingly connected to and slidable along the input shaft 102, it may be provided in a fixed position along the input shaft 102 and be sleeved around the input shaft 102 so as to rotate independently. A sliding dog ring, which may have dog teeth on each axial face thereof, can be provided on the input shaft 102 between two gears, such as gears 131 and 151. In this way, the sliding dog ring can selectively engage the gears 131, 151 to transfer drive between the input shaft 102 and the drive shaft 171 via the selected gear. It can be envisaged that the arrangement shown in Figure 3 can be further modified by providing such a sliding dog ring between gears 141 and 151. Similarly, the gears around the drive shaft 171 of Figure 3 can be modified by providing the sliding drive gear 135 in a fixed position along the drive shaft 171 and sleeving it around the drive shaft 171 so as to rotate independently. A sliding dog ring could then be placed between gears 125 and 135, and another sliding dog ring could be placed between gears 135 and 155. In view of the above, the disclosure is not limited to the sliding element being a gear. Rather, the sliding element need not have gear teeth, but can instead be a sliding dog ring. It will be understood that all of the combinations of gears outlined in relation to Figures 4 to 7 could be achieved using sliding dog rings being each pair of axially-engageable gears. It will be appreciated from the above description that many features of the different examples are interchangeable and combinable. The disclosure extends to further examples comprising features from different examples combined together in ways not specifically mentioned. Indeed, there are many features presented in the above examples and it will be apparent to the skilled person that these may be advantageously combined with one another.

Claims

1. A powertrain for a hybrid power straddle-type vehicle, the powertrain comprising: an internal combustion engine comprising a crankshaft;a first electric machine configured to drive the crankshaft;an input shaft drivingly connected to the crankshaft;a second electric machine drivingly connected to a drive shaft; anda transmission configured to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios.

2. The powertrain of claim 1, wherein a rotor of the first electric machine is directly connected to the crankshaft.

3. The powertrain of claim 1 or claim 2, wherein the crankshaft, the input shaft and the drive shaft are integrated within a crankcase.

4. The powertrain of claim 3, wherein the crankcase comprises at least one opening, the at least one opening being configured to receive at least one of:a piston shaft of the internal combustion engine;a rotational drive element of the first electric machine; and a rotational drive element of the second electric machine.

5. The powertrain of any preceding claim, wherein the crankshaft is adjacent to at least one of the input shaft and the drive shaft in a direction perpendicular to the rotational axis of the crankshaft.

6. The powertrain of any preceding claim, wherein the rotational axis of the crankshaft is colinear with the rotational axis of the first electric machine.

7. The powertrain of any preceding claim, wherein the rotational axes of the crankshaft, the input shaft and the drive shaft are parallel and are provided in a triangular array.

8. The powertrain of any preceding claim, wherein the second electric machine is drivingly connected to the drive shaft via an intermediate shaft.

9. The powertrain of claim 8, wherein the intermediate shaft is colinear with the input shaft.

10. The powertrain of claim 8 or claim 9, wherein the intermediate shaft is provided concentrically within the input shaft.

11. The powertrain of any of claims 8 to 10, wherein the intermediate shaft is drivingly connected to the drive shaft by a gear located at an opposite end of the intermediate shaft to the second electric machine.

12. The powertrain of any preceding claim, further comprising a controller configured to effect movement of the transmission to a configuration in which rotational drive is transferred between the input shaft and the drive shaft at a first speed ratio of the plurality of speed ratios, by controlling at least one of the first electric machine and the internal combustion engine to thereby control a rotational speed of the input shaft in correspondence with a rotational speed of the drive shaft.

13. The powertrain of any preceding claim, wherein the transmission comprises a sliding input element on the input shaft and a sliding drive element on the drive shaft.

14. The powertrain of claim 13, wherein at least one of the sliding input element and the sliding drive element comprises dogs on an axial surface thereof, the dogs being configured for axial engagement with at least one gear on the respective shaft.

15. The powertrain of claim 13 or claim 14, wherein the sliding input element comprises a sliding input gear drivingly connected to the input shaft, the sliding input gear being slidable along the input shaft for selectable engagement with at least one input gear, the at least one input gear being drivingly connected to the drive shaft.

16. The powertrain of claim 15, wherein the at least one input gear comprises a firstinput gear and a second input gear, and the sliding input gear is slidable between:a first position in which the sliding input gear is engaged with the first input gear;a second position in which the sliding input gear is engaged with the second input gear; anda neutral position in which the sliding input gear is engaged with neither the first input gear nor the second input gear.

17. The powertrain of any of claims 13 to 16, wherein the sliding drive element comprises a sliding drive gear drivingly connected to the drive shaft, the sliding drive gear being slidable along the drive shaft for selectable engagement with at least one drive gear, the at least one drive gear being drivingly connected to the input shaft.

18. The powertrain of claim 17, wherein the at least one drive gear comprises a first drive gear and a second drive gear, and the sliding drive gear is slidable between:a first position in which the sliding drive gear is engaged with the first drive gear;a second position in which the sliding drive gear is engaged with the second drive gear; anda neutral position in which the sliding drive gear is engaged with neither the first drive gear nor the second drive gear.

19. A controller for a powertrain of a hybrid power straddle-type vehicle, the controller being configured to:control a power supplied to a first electric machine configured to drive an input shaft;control a power supplied to a second electric machine configured to drive a drive shaft;control a power output of an internal combustion engine configured to drive the input shaft;control a transmission to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios; andeffect movement of the transmission to a configuration in which rotationaldrive is transferred between the input shaft and the drive shaft at a first speed ratio of the plurality of speed ratios, by controlling at least one of the first electric machine and the internal combustion engine to thereby control a rotational speed of the input shaft in correspondence with a rotational speed of the drive shaft.

20. The controller of claim 19, wherein the controller is configured to:determine a charge level of a battery of the powertrain; andcontrol a power supplied to the first electric machine and / or the second electric machine based on the determined charge level.

21. The controller of claim 20, wherein the controller is configured to:supply power from the battery to the second electric machine if the charge level is determined to be above a take-off threshold;start the internal combustion engine using the first electric machine; and use the internal combustion engine to charge the battery if the charge levelis determined to be below the take-off threshold.

22. The controller of claim 20 or claim 21, wherein the controller is configured to discharge the battery by supplying power from the battery to the first electric machine if the charge level is determined to exceed a regenerative braking threshold.

23. The controller of claim 22, wherein the controller is configured to determine the regenerative braking threshold based on a calculation of a continuous maximum charge recuperation of the battery, wherein the continuous maximum charge recuperation of the battery is determined based on a predicted navigational route of the straddle-type vehicle.

24. A powertrain for a hybrid power straddle-type vehicle, the powertrain comprising: an internal combustion engine configured to drive an input shaft, a first electric machine configured to drive the input shaft;a second electric machine configured to drive a drive shaft;a transmission configured to transfer rotational drive between the input shaft and the drive shaft at a plurality of speed ratios; anda controller;wherein the controller is configured to effect movement of the transmission to a configuration in which rotational drive is transferred between the input shaft and the drive shaft at a first speed ratio of the plurality of speed ratios, by controlling at least one of the first electric machine and the internal combustion engine to thereby control a rotational5 speed of the input shaft in correspondence with a rotational speed of the drive shaft.

25. A straddle-type vehicle comprising the powertrain according to any of claims 1 to18 or 24, and / or the controller of any of claims 19 to 23.10

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