FR2899663A3 - Transmission system for e.g. thermal-electric hybrid car, has primary variable speed drive cooperating with secondary variable speed drive for forming transmission unit for moving with continuous variation between urban and common shafts - Google Patents

Abstract

The system has a drive shaft (7) connected with an internal combustion drive engine (1) via a drive clutch (3). An urban shaft (6) is connected with an internal combustion urban engine (2) via an urban clutch (4), where the engines e.g. petrol engines, are provided in a thermal twin-engine drive train. A common shaft (8) is connected with drive wheels. A primary variable speed drive (13) cooperates with a secondary variable speed drive (20) for forming a transmission unit for moving with continuous variation between the urban and common shafts.

Description

Transmission system • for a vehicle equipped with a

  TECHNICAL FIELD OF THE INVENTION The present invention relates, in the field of motorized vehicles, to a transmission for a vehicle equipped with a twin-engine powertrain ensuring both high performance while preserving a low power. fuel consumption and low emissions. The invention relates more particularly to a transmission system for a motor vehicle of high performance, low consumption and low pollutant emissions, provided with a twin-engine powertrain. BACKGROUND OF THE INVENTION The need to meet the demands of motor vehicle users in terms of performance requires manufacturers to equip their vehicles with large engines with a number and / or a volume of cylinders increasingly high. However this solution improving the performance of vehicles has at least two major drawbacks: 20 - an increase in fuel consumption penalizing for the user of the vehicle, via the higher operating cost of the vehicle in the end, an increase in polluting emissions penalizing the vehicle manufacturer, forced to comply with the standards, more and more severe, relating to the levels of pollutant emissions related to the operation of internal combustion engines. In addition, the large motorization is largely oversized in relation to the real needs of a car, especially when it is used in urban and extra-urban areas at prescribed speeds, which accounts for a very large proportion of the movements of users.

  There is therefore a real need to optimize the relationship between the desired performance of users, the cost of operating a car, its consumption and its pollutant emissions, especially during urban and extra-urban use at regulatory speeds. motor vehicle.

  In a known manner, to optimize these parameters, some manufacturers propose hybrid electric-electric vehicles comprising two engines, one thermal, the other electric. The electric motor is used when its power is sufficient compared to the needs of the driver. Beyond that, it is the heat engine that takes the relay. This minimizes the operating time of the engine. This hybrid-electric hybrid solution is cumbersome, complex and very expensive and therefore unsatisfactory. Another known solution described in the French patent application FR 2 727 363 relates to a high performance automobile, comprising propulsion units consisting of two identical internal combustion engines each acting on a rear wheel via a gear train (page 2, lines 28-31, page 4, lines 16-23). The two-engine nature of the disclosed vehicle allows the independent management of each propulsion wheel, without resorting to an action on the braking system or on a torque splitter (page 5, lines 26-30). It follows immediately that this solution favors performance at the expense of fuel consumption and the rate of polluting emissions. Indeed, the presence of two identical, mechanically independent internal combustion engines acting separately on independent wheels can not reduce fuel consumption and pollutant emissions compared to the conventional solution comprising a single internal combustion engine. same type installed on the same vehicle. Furthermore, the device disclosed by the French patent application FR 2 727 363 does not solve the problem of optimizing the power of the two thermal engines of the vehicle to urban and extra-urban use at prescribed speeds. As for the coupling of the two engines via a single transmission system acting simultaneously on all driving wheels in order to optimize the ratio between the desired performance, the operating cost, the consumption and the pollutant emissions of the vehicle, this problematic is not treated in the French patent application FR 2 727 363. Finally, the use of multiple propulsion systems on board vehicles is known as such, for example on aircraft or on ships. However, the plurality of motors is applied there more for reasons of safety than for technical reasons related to the optimization of the ratio between the desired performances, the operating cost, the consumption and the pollutant emissions. Likewise, the coupling of multiple propulsion units on board aircraft or on ships via a single transmission system is expressly avoided to make these assemblies mechanically independent at the expense of operating cost, consumption and polluting emissions. Finally, these propulsion units are located on either side of the plane of symmetry of the mobile. Such an architecture is obviously foreign to motor vehicles commonly used, especially in urban traffic. From this analysis it can be deduced that the state of the art does not propose any solution dealing with the transmission problems for a twin-engine powertrain that ensures both high vehicle performance while preserving low fuel consumption and low pollutant emissions. . SUMMARY OF THE INVENTION The present invention therefore aims to overcome one or more of the disadvantages of the prior art by proposing a transmission system for a motor vehicle of high performance, low consumption and low pollutant emissions, provided with a twin-engine power train. To this end, the invention relates to a transmission system linking each of the rnoteurs of a power unit at least twin engine of a vehicle with at least one drive wheel, the twin-engine powertrain comprising: an internal combustion engine comprising: at least one cylinder, an urban internal combustion engine comprising at least one cylinder, a management equipment comprising a calculator means, sensor means and analyzer means intended to provide data representative of the state of operation of the various elements of the vehicle at the computer means, control and control means for controlling the engines and the transmission system, characterized in that the transmission system comprises: at least one pusher primary shaft connected to the pusher motor via a pushing clutch, 15 to minus an urban primary tree linked with the urban engine via an urban clutch, - at least one secondary shaft In this embodiment, the drive is connected to the drive wheels at least one primary variator cooperating with at least one secondary drive and forming a continuously variable motion transmission means between the shafts, the push clutch and the urban clutch being selectively operable by the control and control means for controlling the respective connection of each of the two motors to the transmission system. In another feature, the primary variator connects the urban primary shaft to the primary pusher shaft. In another feature, the primary drive is mounted on the primary shaft pusher coasting.

  In another feature, the freewheel remains locked until the rotational speed ratio of the pusher primary shaft and the primary drive rotating in the same direction is less than a predetermined value.

  According to another feature, the freewheel is released as soon as the rotational speed ratio of the pusher primary shaft and the primary drive rotating in the same direction is equal to or greater than a predetermined value. In another feature, the secondary drive connects the primary pusher shaft with the common secondary shaft. In another feature, the moment of force from at least one of the two primary shafts is transmitted to the common secondary shaft using the continuously variable motion transmitting means. According to another particularity, the moment of force coming from at least one of the two primary shafts is transmitted to the common secondary shaft by means of circular movement transmission means cooperating with the primary thrust shaft via of a dog. According to another particularity, the two variators are arranged to cooperate with each other by means of control and control means of the management equipment. According to another feature, the common secondary shaft comprises gear trains and clutch with or without synchronizers linked in rotation with the common secondary shaft and cooperating with a ring 25 of a differential. The invention, with its features and advantages, will emerge more clearly on reading the description given with reference to the appended FIG. 1 which represents a schematic diagram of the transmission system according to the invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION As illustrated in FIG. 1, the transmission system according to the invention is arranged on a motor vehicle equipped with a powertrain, for example a twin engine, comprising a propulsion engine. (1) said pusher motor (1), and a main motor (2) said urban engine (2), internal combustion each provided with at least one cylinder referenced respectively (14, 15). The two internal combustion engines (1, 2) are of the conventional type, for example a gasoline engine, a liquefied petroleum gas engine called a LPG engine, a compressed natural gas engine called a CNG engine, a natural gas engine for vehicles said to be CNG engine, alcohol engine, diesel engine etc. Each motor (pusher (1) or urban (2)) can also conventionally drive accessories (not shown in Figure 1), for example an alternator, a pump, an air conditioning compressor, a pump assistance of direction etc. Each engine (pusher (1) or urban (2)) can be provided in a conventional manner equipment ensuring its proper operation (not shown in Figure 1), for example a starter, sensors etc. The fact that the urban engine (2) is a conventional internal combustion engine represents an advantageous characteristic which fundamentally differentiates the present powertrain from the other so-called hybrid systems, mentioned above, comprising two engines, one thermal and the other electric. . The transmission system comprises: at least one primary pusher shaft (7) connected with the pusher motor (1) via a pusher clutch (3), at least one urban primary shaft (6) linked with the urban engine (2) via an urban clutch (4), at least one common secondary shaft (8) comprising gear trains (17, 18) and synchronizers connected in rotation with the common secondary shaft (8) and cooperating with a ring (16) of a differential (19), the latter (7) being mechanically connected with the drive wheels (not shown in FIG. 1), means (13, 20) for transmitting motion between the shafts (7, 6, 8) which will be described in more detail below. By clutch (pusher (3) or urban (4)) will be understood in the following any coupling system and decoupling whose operation can be of the manual type, automatic or semi-automatic such as, for example a conventional mechanical clutch or centrifugal or equivalent system, coupler, hydraulic converter etc. In a variant of the invention, the links of the clutches (3, 4) with the respective primary shafts (7, 6) are operated by means of the well-known motion transmission means, for example a chain, a belt, a gear train etc. The twin-engine powertrain is designed to provide the vehicle with high performance while maintaining low fuel consumption and low emissions. For this purpose, the two heat engines (1, 2) are used complementary to one another. The urban engine (2) operates permanently from the start of the vehicle by delivering sufficient power for a current use which represents a large majority of the operating time of the motor vehicle, for example in an urban area or in an extra zone. urban at regulatory speeds. The pusher motor (1) occasionally comes into operation only when it is necessary, for example when there is a high demand for power at high loads, on the motorway, etc., thus providing a surplus of necessary power. Another example relates to the case where the pusher motor (1) is operated to provide the reverse gear of the vehicle.

  In one mode of operation, the urban engine (2) stops driving the transmission system as soon as the pusher motor (1) comes into operation to optimize the power of the powertrain. In this case, the urban engine (2) resumes driving the transmission system as soon as the demand for power drops to a predetermined level and when the pusher engine is ready to cease operation, so as to optimize the power of the engine. powertrain. Once the urban engine (2) has resumed driving the transmission system, the pusher motor (1) stops. In another mode of operation, while the vehicle is powered by the urban engine (2), the pusher motor (1) idles whether or not to participate in driving the transmission system. This mode of operation is particularly adapted to a so-called sports driving regime requiring reduced response time. Indeed, the pusher motor 15 (1) is then constantly in standby, ready to deliver instantly, without the need to waste time (a few tenths of a second) to start the pusher motor (1), a surplus of power required following a power demand expressed, for example by a sudden depression of the accelerator pedal by the driver of the vehicle. In the embodiment in Figure 1, the pusher motor (1), for example three-cylinder (14) in line, is more powerful than the urban engine (2), for example two cylinders (15) in line. In another embodiment, the power of the pusher motor (1) is identical to that of the urban motor (2). The transient between the urban engine (2) alone and the pusher motor (1) or the two engines simultaneously is managed using a management equipment (not shown in FIG. 1) known from the prior art and used, for example on thermal-electric hybrid cars mentioned above. This management equipment conventionally comprises a computer with a processing unit called CPU (English Computer Processing Unit), with a multi-layer architecture. The computer receives via various sensors and analyzers forming part of the assembly called the management equipment and installed on the vehicle, the data representative of the state of operation of the vehicle and the various elements that compose it, for example the motors (1, 2), transmission system etc. The computer then optimizes the operating speeds of these organs using the various control and control means which are also part of the assembly called the management equipment, acting inter alia on the two engines io (1, 2) and the transmission system. To ensure the transmission of the moment of force from the twin-engine powertrain to provide the vehicle with both high performance and low fuel consumption (and ultimately low emissions), the driven transmission system by the management equipment advantageously has two clutches and means (13, 20) for transmitting motion between the shafts (7, 6, 8). The two clutches (3, 4) can be selectively actuated to control the connection of each of the two motors (1, 2) to the transmission system. Thus, the presence of these two clutches (3, 4) advantageously makes it possible to ensure perfect synchronization of the two motors (1, 2), on the one hand, to best distribute their powers according to the will of the driver of the vehicle translated, for example by the action exerted on an accelerator pedal (for example, a progressive or brutal depression), and, secondly, to best transmit the moment of force to the transmission system. This without creating interference between the two motors (1, 2) harmful to their synchronized operation and while optimizing fuel consumption. In addition to the advantageous presence of the two clutches (3, 4) mentioned above, the transmission system comprises the means for transmitting motion between the shafts (7, 6, 8), said to be continuously variable as formed by at least one primary dimmer (13) co-operating autonomously or with the control and control means of the management equipment with at least one secondary dimmer (20). The primary variator (13) connects the urban primary shaft (6) to the primary pusher shaft (7).

  The secondary drive (20) connects the pusher primary shaft (7) with the common secondary shaft (8). In another embodiment of the invention, the primary variator (13) is advantageously freewheeling on the pusher primary shaft (7).

  In known manner, the freewheel (30) comprises an outer ring opposite to an inner ring oriented towards the primary pushing shaft (7). The outer ring is sealed, for example on the primary variator (13), the inner ring is sealed, for example on the primary pusher shaft (7). Of course, the reverse fitting with the outer ring of the freewheel (30) sealed on the pusher primary shaft (7) and the inner ring of the freewheel (30) sealed on the primary variator (13) can also to be considered. According to the well known operating principle of the freewheel (30), as soon as the ratio of the rotational speeds between the inner ring and the outer ring rotating in the same direction is below a certain predetermined value, both freewheel rings (30) are engaged. Once this threshold value is reached, the two rings of the freewheel (30) begin to evolve independently of each other by decoupling the primary variator (13) from the primary pusher shaft (7). In other words, the freewheel (30): remains locked until the rotational speed ratio (V7 / V13) of the pusher primary shaft (7) and the primary variator (13) rotating in the same direction is less than a predetermined value, for example, V7 / V'13 <1, where V7 is the rotational speed of the pusher primary shaft (7) and V13 is the rotational speed of the primary variator (13) , is released as soon as the rotational speed ratio (V7N13) of the pusher primary shaft (7) and the primary converter (13) rotating in the same direction is equal to or greater than a predetermined value, for example, V7N13 1. This allows, for example, to maintain the operation of the two motors (1, 2) without necessarily cutting the link of the urban engine (2) with the transmission system by the urban clutch (3). Thus, the two motors (1, 2) can rotate with two different speeds of rotation without braking each other. This embodiment advantageously makes it possible to use a centrifugal urban clutch (4) which is robust and inexpensive. In the absence of the mounting of primary variator (13) freewheeling on the pusher primary shaft (7), it is necessary to use a controlled urban clutch (4) which is more complex (and therefore less robust) and expensive. Finally, to enable the pusher motor (1) to provide reverse gear for the vehicle, the transmission system comprises circular motion transmission means (21) connecting the pusher primary shaft (7) to the common secondary shaft (8). Thus, the moment of force coming from at least one of the two motors (1, 2), for example the pusher motor (1), is transmitted to the common secondary shaft (8) using these circular motion transmission means (21) cooperating with the pusher primary shaft (7) via a clutch (22) which advantageously makes it possible to select the forward or reverse gear. The architecture of the transmission system according to the invention and in particular that of its continuously variable motion transmission means (13, 20) formed by the inverters (13, 20) in series offers several advantages. By way of illustration, it is possible to couple one of the two motors (1, 2) or the two motors simultaneously with the drive wheels. Similarly, the transmission system according to the invention allows to have a very large opening for the urban engine (2) to be able to accompany the pusher motor (1) up to the maximum speed. Mounting the primary variator (13) freewheeling on the pusher primary shaft (7) makes it possible to use only the pusher motor alone for propulsion, the urban engine remaining in standby to operate the accessories. The transmission system according to the invention also allows to have a small opening for the pusher motor (1) with a single drive (20) for the strong torque. Note also that the two inverters series (13, 20) offer a very important gear for the urban engine (2) to facilitate starting the vehicle using the only urban engine (2) at the maximum low torque.

  To illustrate how the transmission system according to the invention responds, with a continuous variation, to the need to continuously optimize the load and speed conditions of each of the two motors (1, 2) separately or coupled to provide the vehicle with High performance, low consumption and low pollutant emissions, its 1s operation will now be described with reference to the example in Figure 1. Mode of operation n 1 When the power required, for example by a depression of the pedal d accelerator by the driver of the vehicle, is less than 20 that can develop the urban engine (2) economically in terms of consumption, only this urban engine (2) operates. It transmits the moment of force via the urban clutch (4), the urban primary shaft (6) and the primary variator (13) to the pusher primary shaft (7). The freewheel (30) of the primary variator (13) is blocked, the pusher primary shaft (7) is thus rotated by the primary variator (13). To minimize energy losses, the pusher clutch (3) controlled by the control and control means of the management equipment is in the disengaged position. The moment of force coming from the urban engine (2) is thus sent back by the pusher primary shaft (7) via the secondary variator (20) to the common secondary shaft (8) which then transmits it to the crown (16). Differential (19).

  In this mode of operation n 1, the two variators (13, 20) cooperate by searching for the best operating point. Operating mode n 2 When the requested power, for example by depression of the accelerator pedal by the driver of the vehicle, is greater than that which can develop the urban engine (2) economically in terms of consumption, but less than that of the pusher motor (1) alone, the management equipment starts the pusher motor (1). Then, the pusher clutch (3) controlled, initially disengaged (operating mode n 1), is put in the engaged position. The pusher motor (1) is then coupled with the pusher primary shaft (7) and begins transmitting the moment of force to the common secondary shaft (8) via the secondary drive (20). According to the well-known operating principle of the free wheel (30) recalled above, as soon as the ratio of the rotational speeds between the inner ring and the outer ring of the freewheel (30) rotating in the same direction, is below a certain predetermined value (case of the operating mode n 1 having, for example, the ratio V7N13 <1), the two rings of the freewheel (30) are engaged (the primary variator 20 (13) then drives the pusher primary shaft (7)). Once this threshold value is reached, the two rings of the freewheel (30) begin to evolve independently of each other by decoupling the primary variator (13) from the primary pusher shaft (7). This is precisely the case of the operating mode n02 when the pusher motor (1) coupled with the pusher primary shaft (7) has developed sufficient power after its starting so that the rotation speed (V7) the primary shaft pusher (7) is, for example, greater than the rotational speed (V13) of the primary variator (13) driven by the urban engine (2). The freewheel (30) is then unlocked, the urban motor (2) is disconnected from the common secondary shaft (8) which therefore remains driven by the single pusher motor (1) via the secondary drive (20). As for the urban engine (2), it continues to operate at the speed required to drive the accessories.

  In this operating mode n 2, the two inverters (13, 20) do not cooperate because the freewheel (30) is unlocked, the second inverter (20) seeking only the best operating point of the pusher motor.

  Operating mode n 3 When the requested power, for example by a depression of the accelerator pedal by the driver of the vehicle, is greater than that which can develop the pusher motor (1) economically in terms of consumption, the management equipment accelerates the urban engine (2) so that the ratio of rotational speeds between the inner ring and the outer ring of the freewheel (30) returns below the threshold value (V71V13 <1 in the example herein -above). Once the freewheel (30) is blocked, the two motors (1, 2) are coupled to the common secondary shaft (8) from the pusher primary shaft (7). The primary drives (13) then seek the best operating point of the urban engine (2). Similarly, the secondary drive (20) seeks the best operating point of the pusher motor (1). It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments should be considered by way of illustration, but may be modified within the scope defined by the scope of the appended claims, and the invention should not be limited to the details given above.

  In particular, although the invention has been illustrated by an example where the transmission system according to the invention is used on a motor vehicle, it will be understood that the transmission system according to the invention can also be adapted to all applications requiring Power levels far removed and for which the time spent at low power are significant (generator, pumping, rail traction ...). Similarly, although the invention has been illustrated by an example where the

  transmission system according to the invention is used for a two-engine powertrain with two engines (1, 2) internal combustion, it will be understood that the transmission system according to the invention can also be used in a configuration where the two engines are replaced by motors whose operating principle differs from the principle of internal combustion operation. It can be, for example two electric motors, two fuel cell engines etc.

  Similarly, although the invention has been illustrated by examples where the transmission system according to the invention is used for a twin-engine powertrain, it will be understood that the system according to the invention can also be used for a powertrain with more than two engines, for example with at least three engines. Another example relates to a configuration of the transmission system according to the invention arranged for a powertrain with at least three engines of which at least one of the three engines may not be thermal. It may be, for example, an electric motor, a fuel cell engine, etc.

  Finally, although the invention has been illustrated by examples where the axes of the shafts (7, 6, 8) of the transmission system according to the invention and the crankshaft axes of the two motors (1, 2) are parallel to each other. relative to the others (Figure 1), it will be understood that the system according to the invention can also be used in a configuration where some of these axes or all the axes are either inclined relative to each other or perpendicular to each other others, inclined relative to one and perpendicular to the others.

Claims (8)

  A transmission system linking each of the engines of at least one twin engine powertrain of a vehicle with at least one driving wheel, the twin-engine power train comprising: an internal combustion engine (1) comprising at least one cylinder ( 14), an urban engine (2) with internal combustion comprising at least one cylinder (15), a management equipment comprising a calculator means, to means sensors and analyzer means for providing data representative of the state of operation different elements of the vehicle by means of computer, control and control means for controlling the motors (1,   2) and the transmission system, characterized in that the transmission system comprises: at least one primary pusher shaft (7) connected with the pusher motor (1) via a pusher clutch (3) ,. at least one urban primary shaft (6) connected with the urban engine (2) via an urban clutch (4), at least one common secondary shaft (8) connected with the driving wheels, at least one cooperating primary variator (13). with at least one secondary variator (20) to form at least one continuously variable motion transmission means between the urban primary shaft (6) linked with the urban motor (2) and at least one common secondary shaft (8) connected with the driving wheels, at least one transmission means between the pusher primary shaft (7) connected with the pusher motor (1) via a pusher clutch (3) and at least one common secondary shaft (8) connected with the wheels motor, the pusher clutch (3) and the urban clutch (2) selectively operable by the control and control means for controlling the respective connection of each of the two motors (1, 2) to the transmission system. 2. Transmission system according to claim 1, characterized in that the primary variator (13) connects the urban primary shaft (6) to the primary pusher shaft (7).   3. Transmission system according to claim 1 or 2, characterized in that the primary variator (13) is mounted on the primary shaft pusher (7) freewheeling.   4. Transmission system according to claim 3, characterized in ~ o that the freewheel (30) remains locked until the ratio of rotational speeds (V71V13) of the primary shaft pusher (7) and the variator primary (13) rotating in the same direction is less than a predetermined value.   Transmission system according to claim 3 or 4, characterized in that the freewheel (30) is released as soon as the rotational speed ratio (V7N13) of the primary pusher shaft (7) and the primary variator ( 13) rotating in the same direction is equal to or greater than a predetermined value.   6. Transmission system according to one of claims 1 to 5, characterized in that the secondary drive (20) connects the pusher primary shaft (7) with the common secondary shaft (8).   Transmission system according to one of Claims 1 to 6, characterized in that the moment of force originating from at least one of the two primary shafts (7, 6) is transmitted to the common secondary shaft (8) at using the continuously variable motion transmission means (13, 20). 25   Transmission system according to one of Claims 1 to 7, characterized in that the moment of force originating from at least one of the two primary shafts (7, 6) is transmitted to the common secondary shaft (8) at using the circular motion transmission means (21) cooperating with the pusher primary shaft (7) by means of a dog clutch (22). Transmission system according to one of claims 1 to 8, characterized in that the two inverters (13, 20) are arranged to cooperate with each other by means of control and control means of the management equipment. 10. Transmission system according to one of claims 1 to 9, characterized in that the common secondary shaft (8) comprises gear trains (17, 18) and clutch with or without synchronizers connected in rotation with the common secondary shaft (8) cooperating with a ring gear (16) of a differential (19).