FR3087161A1 - HYBRID DRIVE CHAIN FOR MOTOR VEHICLE - Google Patents

Abstract

The invention relates mainly to a traction chain (10) for a motor vehicle, characterized in that it comprises: -a heat engine (11), -a device for filtering acyclisms (12) of the heat engine (11), - a gearbox (13), - a clutch (KO) mounted on the one hand between the filtering device for acyclisms (12) of the heat engine (11) and on the other hand the gearbox (13), - a rotary electric machine (17) coupled to an input shaft (18) of the gearbox (13), - a starter (20) capable of ensuring a starting of the heat engine (11), and - a supervisor (21 ) of the traction chain (10) configured to control a starting of the thermal engine (11) via a control of the starter (20) while the clutch (KO) is in an open state so as to isolate the thermal engine (11 ) relative to the rest of the traction chain (10).

Description

The present invention relates to a hybrid powertrain for a motor vehicle.

There are known hybrid traction chains comprising a heat engine, a gearbox, a clutch mounted on the one hand between the heat engine and on the other hand the gearbox. An output of the gearbox is connected to a differential, which is connected to the wheels via transverse transmissions.

A rotating electrical machine is coupled to an input shaft of the gearbox. This electric machine is able to operate in engine mode to ensure traction of the motor vehicle or starting of the heat engine. The electric machine is also capable of operating in alternator mode for recharging batteries of the motor vehicle and / or supplying electrical consumers directly from the on-board network.

When the heat engine is started during an electric driving phase, a torque is taken from the electric machine. This causes a drop in torque at the wheels and therefore an unpleasant ride.

The invention aims to effectively remedy this drawback by proposing a traction chain for a motor vehicle comprising:

- a heat engine,

- a device for filtering acyclism from the heat engine,

- a gearbox,

- a clutch mounted on the one hand between the filtering device for acyclic movements of the engine and on the other hand the gearbox,

- a rotating electric machine coupled to an input shaft of the gearbox,

a starter capable of ensuring starting of the thermal engine, and

- a traction chain supervisor configured to control starting of the combustion engine via a command from the starter while the clutch is in an open state so as to isolate the combustion engine from the rest of the traction chain.

The invention thus makes it possible, thanks to the use of the starter and of the clutch capable of isolating the heat engine from the rest of the traction chain, to ensure that said heat engine is started during an electric driving phase. without torque drop at the wheels. This improves the driving comfort of the motor vehicle during this life phase.

In one embodiment, the supervisor is configured to control the clutch closing when the engine and the input shaft of the gearbox have substantially identical rotation speeds.

According to one embodiment, the heat engine is a three-cylinder petrol type turbocharged engine.

According to one embodiment, the gearbox is a gearbox with double clutches.

According to one embodiment, the device for filtering acyclisms is a double pendulum-type damping flywheel.

In one embodiment, the electric machine is connected to the input shaft of the gearbox by a movement transmission device.

According to one embodiment, the movement transmission device comprises a belt.

According to one embodiment, the starter comprises a direct current electric motor and a pinion intended to mesh with a starter ring of the heat engine.

The invention further relates to a motor vehicle comprising a traction chain as defined above.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

[Fig. 1] is a schematic representation of a traction chain according to the present invention;

[Fig. 2] is a diagram of the different life situations of the traction chain according to the present invention.

FIG. 1 shows a traction chain 10 for a motor vehicle comprising a heat engine 11 associated with a device for filtering acyclisms 12 of the heat engine 11, as well as a gearbox 13, in particular of the double clutch type. A clutch KO is mounted on the one hand between the filtering device for acyclisms 12 of the heat engine 11 and on the other hand the gearbox 13.

An output of the gearbox 13 is connected to a differential 14, which is connected to the wheels 15 via transverse transmissions 16.

In addition, a rotary electric machine 17 is coupled to an input shaft 18 of the gearbox 13. This electric machine 17 is capable of operating in engine mode to ensure traction of the motor vehicle or starting the engine. 11. The electric machine 17 is also able to operate in alternator mode to recharge the batteries of the motor vehicle and / or directly supply electrical consumers from the on-board network.

A starter 20, the operation of which is described in more detail below, is capable of ensuring starting of the heat engine 11. A supervisor 21 of the traction chain 10 is capable of controlling the various elements 11, KO, 13, 17, and 20 of the traction chain 10.

Preferably, the heat engine 11 is a three-cylinder petrol type turbocharged engine, because this corresponds to an optimal configuration in terms of performance, performance, consumption, and reduced emissions of polluting particles. Alternatively, the heat engine 11 may however be an atmospheric engine, or a diesel type engine. The number of cylinders can be different from three, notably being worth two or four or more. It depends on the application and in particular on the power of the vehicle sought.

The heat engine 11 is mechanically connected to the acyclism filtering device 12 which consists of a double pendulum damping flywheel to filter as much as possible the acyclisms of the heat engine 11. This double pendulum damping flywheel 12 has a primary inertial mass J1 and a secondary inertial mass J2 connected to each other by circumferential springs 22. In addition, the secondary inertial mass J2 comprises pendulums 23 having a circumferential movement of a few millimeters. Such a configuration makes it possible to reduce the noises of gearboxes, in particular the noises of shot (which originate from the acyclism of the engine transmitted to the idler gears and idle shafts of the BV), as well as the humming inside the vehicle (which has for origin the acyclism of the engine transmitted to the wheels of the vehicle).

The opening of the clutch KO isolates the heat engine 11 when the supervisor 21 determines that optimal operation is obtained by driving in pure electric mode (or that the driver requests a ride in pure electric mode) without have to counteract the friction torque of the heat engine 11.

The KO clutch also makes it possible to start the heat engine 11 with the starter 20 without loss of torque in the traction chain 10 during starting, as is explained in more detail below. When the vehicle is traveling in hybrid mode or pure thermal mode, the KO clutch is closed.

Downstream of the KO clutch is arranged the electric machine 17 which is connected to the input shaft 18 of the gearbox 13 via a movement transmission device 24 comprising in particular a belt . Alternatively, the electric machine 17 is connected to the input shaft 18 of the gearbox 13 by a cascade of sprockets or a chain.

The electric machine 17 is powerful enough to drive the vehicle during a phase of pure electric traction. This electric machine 17 can thus operate in electric motor mode in the traction phases of the vehicle or in alternator mode in the deceleration phases of the vehicle corresponding in particular to regenerative braking phases and / or in the recharging phases of traction batteries and / or the service battery. The electric machine 17 could be a synchronous or asynchronous type machine able to operate in particular under a direct voltage of 48 Volts supplied by the electric network of the vehicle. It is even possible to use an electric machine 17 with direct current. The type of machine used and its power depend on the application.

The gearbox 13 is of the double clutch type (or DCT for Dual Clutch Transmission in English). Such a gearbox 13 has better performance than conventional automatic gearboxes for performance in longitudinal dynamics and very close driving pleasure.

This gearbox 13 includes a first clutch K1 and a second clutch K2. The first clutch K1 is associated with a first pair of primary shaft AP1 and secondary AS1 carrying the even ratios. The second clutch K2 is associated with a second pair of primary shaft AP2 and secondary AS2 carrying the odd ratios of the gearbox 13.

In operation, when a report is engaged, the next desired report is preselected by means of the box synchronizers. The clutches K1, K2 are then crossed to effect the gear change, which makes it possible not to undergo a torque break in the traction chain 10. Thus, the driver does not realize that the gear change has occurred.

It should be noted that such a gearbox 13 has a high sensitivity to acyclisms of the engine 11 insofar as, when a gear is engaged, the secondary shaft which does not carry a pinion forming said gear engaged is crazy and generates a noise of shot due to the teeth of the pinion which collide with the teeth of the crown of the differential 14. The use of a double pendulum damping flywheel 12 is therefore particularly well suited to filter the acyclisms of the engine thermal 11 at the input of the gearbox 13, in particular the acyclisms of a three-cylinder engine which are more important than those of a four-cylinder engine (of the same displacement). The configuration associating a three-cylinder heat engine 11, a double pendulum damping flywheel 12, as well as a double clutch gearbox 13 is therefore optimal in terms of acoustic and vibratory performance.

The differential 14 disposed at the outlet of the gearbox 13 is mechanically connected to the transverse transmissions 16 which drive the front wheels 15 of the vehicle. Alternatively, the differential 14 can be coupled to a transfer case (not shown) to equip a four-wheel drive vehicle.

In addition, the supervisor 21 is configured to control a start of the engine 11 via a command from the starter 20 when the vehicle is traveling in pure electric mode while the clutch KO is open and the electric machine 17 is already in operation. operation to advance the vehicle. The opening of the clutch KO makes it possible to isolate the heat engine 11 from the rest of the traction chain 10. Thus, starting the heat engine 11 does not cause a drop in torque in the traction chain 10.

When the engine 11 is started by the starter 20, the supervisor 21 is configured to control a closing of the clutch KO when the engine 11 and the input shaft 18 of the gearbox 13 have substantially identical rotation regimes.

The starter 20 is preferably a reinforced starter comprising an electric motor operating only in engine mode (and not in alternator mode) as well as a pinion intended to mesh with a crown for starting the heat engine 11. By reinforced starter, a starter is understood to have constituent parts (enlarged brushes, brush holder, speed reducer, contactor, launcher, meshing pinion) having a configuration enabling it to withstand 300,000 to 400,000 operating cycles. Such a starter 20 has the advantage of being robust and inexpensive.

Alternatively, the starter 20 may take the form of a more expensive alternator but less noisy than a starter in some cases. The alternator starter is then coupled to the internal combustion engine on the accessories front via a belt or a movement transmission chain. We can also use a standard emergency starter sized to withstand 30,000 to 50,000 operating cycles.

The electric machine 17 can also behave like a starting machine when the clutch KO is closed and the clutches K1 and K2 are open.

Described below, with reference to Figure 2, the different possible life situations with the traction chain 10 according to the invention. State o corresponds to an open state and state f corresponds to a closed state of the corresponding KO, K1, K2 clutch.

During a start phase of the heat engine 11 Dem mth, the starter 20 (STT for Stop and start in English) controlled by the supervisor 21 can start the heat engine 11 without causing a drop in torque in the rest of the drive chain while the KO clutch is open. Similarly, with the clutch KO closed and the clutches K1 and K2 open, the electric machine 17 (MEL) can start the heat engine 11.

During a rolling phase in pure electric mode R elec, while the clutch KO is open, and the clutch K1 or K2 is closed, the electric machine 17 can drive the vehicle without having to fight against friction of the heat engine 11.

During a rolling phase in pure thermal mode R_th, while the clutch KO is closed and the clutch K1 or K2 is closed, the thermal engine 11 Mth can drive the vehicle in pure thermal mode. It is then ensured that the induced current of the electric machine 17 is zero so that the electric machine 17 does not take any torque from the heat engine 11.

During a rolling phase in hybrid mode R_hy, while the clutch KO is closed and the clutch K1 or K2 is closed, the electric machine 17 and the heat engine 11 can drive the motor vehicle together.

During a phase of recharging the batteries when the vehicle is stopped Rech_batt_a, while the clutch KO is closed and the clutches K1 and K2 are open, the heat engine 11 can drive the electric machine 17 to recharge the vehicle batteries.

During a phase of recharging the batteries while driving Rech_batt_r, while the clutch KO is closed and the clutch K1 or K2 is closed, the heat engine 11 drives the traction chain 10 and there no longer remains only to operate the electric machine 17 in alternator mode so that the electric machine 17 draws torque from the traction chain 10 to generate current and recharge the batteries.

It is also possible to provide an Opt_PF phase for optimizing the operating point of the heat engine 11. If the traction chain 10 according to the invention does not make it possible to optimize the operating point of the heat engine 11 in speed, it optimizes the operating point of the heat engine 11 under load.

Thus, in the case where for a given engine 11 rotation speed, the optimum operating point of the heat engine 11 in terms of efficiency is at a torque greater than the current torque, the supervisor 21 controls the electric machine 17 so that it takes a suitable level of torque from the traction chain 10 to reach the optimum operating point of the engine 11.

In the case where for a given engine speed 11, the optimum operating point in terms of efficiency is at a torque lower than the current torque, the supervisor 21 controls the electric machine 17, so that it provides a level of torque adapted to the traction chain 10 in order to reach the optimum operating point of the engine 11.

Claims (6)

Claims [Claim 1] Traction chain (10) for a motor vehicle, characterized in that it comprises: a heat engine (11), a device for filtering acyclisms (12) of the heat engine (11), - a gearbox (13), - a clutch (KO) mounted on the one hand between the acyclism filtering device (12) of the heat engine (11) and on the other hand the gearbox (13), - a rotary electric machine (17) coupled to an input shaft (18) of the gearbox (13), a starter (20) capable of ensuring starting of the heat engine (11), and - a supervisor (21) of the traction chain (10) configured to control a starting of the heat engine (11) via a control of the starter (20) while the clutch (KO) is in an open state so as to isolate the heat engine (11) relative to the rest of the traction chain (10). [Claim 2] Traction chain according to claim 1, characterized in that the supervisor (21) is configured to control a closing of the clutch (KO) when the engine (11) and the input shaft (18) of the gearbox (13) has substantially identical rotation regimes. [Claim 3] Traction chain according to claim 1 or 2, characterized in that the heat engine (11) is a turbocharged engine with three cylinders of the petrol type. [Claim 4] Traction chain according to any one of claims 1 to 3, characterized in that the gearbox (13) is a gearbox with double clutches (K1, K2). [Claim 5] Traction chain according to claim 4, characterized in that the acyclism filtering device (12) is a double pendulum-type damping flywheel. [Claim 6] Traction chain according to any one of claims 1 to 5, characterized in that the electric machine (17) is connected to the input shaft (18) of the gearbox (13) by a motion transmission device (24). [Claim 7] Traction chain according to claim 6, characterized in that the movement transmission device (24) comprises a belt. 5 [Claim 8] Traction chain according to any one of claims 1 to 7, characterized in that the starter (20) comprises a direct current electric motor and a pinion intended to mesh with a starter ring of the heat engine ( 11). 10 [Claim 9] Motor vehicle characterized in that it comprises a traction chain (10) as defined according to any one of the preceding claims.