RU2459719C2 - Automotive combined power plant and electric power converter there for - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to combined power plants of hybrid vehicles. Conversion module comprises two electric machines and transmitter made up of mechanical adder of torques. Said adder comprises case. Said case houses two input shafts to throw in electric machines, output shaft to engage with load and tooth gearing. Electric machines are attached to adder case and connected directly to its input shafts. Said tooth gearing is made up of two pairs of constant-mesh gears. Said pairs feature different gear ratio. Gear ratio of every pair is defined by matching electric machine frequency with vehicle rpm.

EFFECT: higher power output, reduced losses in transmission.

4 dwg

Description

The invention relates to the field of transport engineering, more specifically to combined power plants, designed primarily for hybrid vehicles for various purposes and with a variety of layout solutions: with front-wheel or rear-wheel drive.

The problem solved by the invention is aimed at expanding the arsenal of efficient combined power plants and power conversion modules for them, which are economical to manufacture due to the achieved level of unification and typification and structural simplification, and during operation, by increasing the efficiency of traction engines and reducing transmission losses .

Known combined power plant (KEU), containing the drive shaft of the drive wheels of the vehicle (TS) and associated with it a heat engine, electric machine-generator and traction electric machine, as well as an inverter and energy storage (EP 1433643, 1999), in which both electric machines are mounted inside a common housing. The disadvantage of this KEU is the inability to operate the electric machine-generator in traction mode most of the time the KEU operates and the inability to operate the traction electric machine in this highly efficient range.

The closest analogue (prototype) of the proposed combined power plant is defined installation, containing the drive shaft of its drive wheels, the engine is a generator unit and an electric power conversion unit that includes two electric machines and a transmitting device, the output shaft of which is connected to the drive shaft of the drive wheels, and inverter and energy storage devices (WO 2008/056067 A1, 2008).

In the prototype, the heat engine block is combined with a power conversion unit by a transmitting device (adder) made in the form of a planetary mechanism containing two planetary gear sets and two additional gearboxes, also planetary gears, one for each shaft. The planetary mechanism transmits to the driving wheels of the vehicle the total accumulated torque from two electric machines and a heat engine in the following order. A part of the torque from the heat engine is supplied to the epicycle of the first planetary gear set, and the torque from the first electric machine is supplied to the sun wheel of the same series. The carrier of this planetary gear set is connected with the sun gear of the first additional planetary gearbox, from the epicyclic wheel of which the summarized torque is transmitted via a chain drive to the epicyclic wheel of the second planetary gear set, which is at the same time a similar element of the second additional planetary gearbox that receives torque from a second electric machine, the shaft of which connected to the sun wheel of this gearbox. The second-row sun wheel through a chain drive receives the remainder of the torque from the heat engine, and the second planetary gear carrier transfers the summed torque to the shaft connected by a gear transmission to the common vehicle transmission, and transfers the summed torque to its drive wheels. Moreover, in the prototype it is impossible to use the driving mode using traction only from a heat engine, which is a disadvantage of such a KEU.

Another disadvantage of the prototype is the need for a heat engine to operate the vehicle on traction from both electric machines, which significantly worsens the fuel and economic performance of KEU, as well as restrictions on the use of traction wheels from two electric machines at once, because the mechanical connection of the heat engine with the electric energy conversion unit, and therefore with the drive wheels of the vehicle, necessitates the use of the first electric machine as a generator. This means that in such a KEU the principle of its operation cannot be realized, in which the vehicle speed range is serviced by two equivalent electric machines operating sequentially in the effective efficiency zone. The transmission of power from all the traction engines to the drive shaft of the drive wheels of the vehicle through a transmitting planetary mechanism with the integration of transmission lines (according to the above-described algorithm for their reception, summation and delivery) caused a significant structural complication of this mechanism. The use of an adder of such a design in the KEU does not allow to ensure the operation mode in the zone of effective efficiency, it prevents the implementation of the electric power conversion unit in it in the form of a universal unified module.

The closest analogue (prototype) of the proposed electric power conversion module is the device according to patent US 7186197, 2007, which contains two electric machines and a transmitting device in the form of a mechanical totalizer of moments, having a housing with two parallel input shafts for connecting electric machines, an output shaft for connecting the load, a planetary gearbox made in the form of a differential and an additional reduction gear designed to coordinate the angular velocities associated elements. Electric machines transmit torques to the output shaft of the device, working simultaneously and in concert. The transmission of torque from only one electric machine is possible, while the shaft of the second electric machine does not rotate. The transmission of torque to the output shaft from both electric machines is carried out at different or the same speed modes of operation, and the planetary gearbox ensures coordination of the angular speeds of their shafts with the angular speed of the output shaft of the device through an additional downshift located on the output shaft. At the same high-speed mode of operation of electric machines, the epicyclic gears of the gearbox rotate in one direction and transmit torque to the output element of the differential, and from it through an additional reduction gear to the output shaft of the device. When the angular speeds of the shafts of electric machines are different, the sun gears of the planetary gearbox, rotating also with different angular speeds, cause the satellites to rotate in opposite directions, which makes it possible to compensate for the difference in the angular speeds of the shafts of electric machines, bringing the value of the angular velocity of rotation of the planetary gear carrier to the average between the angular speeds of rotation of satellites. From the carrier, the torque is transmitted to the output element of the differential, and from it through an additional reduction gear to the output shaft of the device. When the torque is transmitted to the output shaft of the device by one electric machine, the adder functions in a similar way.

The main disadvantage of the prototype is its lack of a function to bring electric machines to the operating mode in the zone with maximum efficiency, because it is impossible to ensure the speed range of its output shaft in accordance with the speed range of the vehicle. Also its disadvantages include the use in the adder as transmitting gears of a special planetary gearbox saturated with a large number of elements and connections, which is structurally rather complicated. For the same reason, the use of an adder with such a gearing in the electric power conversion module for the KEU TS and the presence of a reduction gear in it in the form of an epicyclic reducer on the output shaft causes the probability of unproductive power losses in the installation.

The technical result obtained by using the inventions is to implement the task.

The invention consists in the following.

- In a combined power plant of a vehicle containing a drive shaft of its driving wheels, an engine-generator unit and including two electric machines and a transmission device, the output shaft of which is connected to the drive shaft of the drive wheels, at least one electric power conversion unit, and also the inverter and buffer energy storage devices, according to the invention, the electric power conversion unit is made in the form of a unified module mounted on the vehicle carrier system ayuschego during plant operation output of each of the electrical machine in a high efficiency zone by matching its frequency range from the vehicle speed range in which the transmitting device is a mechanical totalizer moments, requiring no external control, and the two electrical machines are mounted on the housing of the adder.

Moreover, the installation may contain several electric power conversion modules located on the side of its drive wheels and the components that make up its basis, such as the engine-generator unit, the inverter and buffer energy storage devices, can also be made in the form of unified modular units.

, где U_M - передаточное число шестеренчатой пары модуля, U_ГП - передаточное число главной передачи трансмиссии транспортного средства,

- граничная линейная скорость,

- линейная скорость транспортного средства.- In a power conversion module, for example, for a combined power plant containing two electrical machines and a transmission device in the form of a mechanical moment totalizer, having a housing with two parallel input shafts located therein for connecting electrical machines, an output shaft for connecting the load and gear transmission gears , according to the invention, electric machines are mounted on the adder casing and connected to its input shafts directly, and as gears gearing, the adder contains two gear pairs of constant gearing made with different gear ratios and the gear ratio of each pair is determined by the ratio of the boundary linear speed corresponding to the angular velocity of the shaft of the electric machine, which determines the boundary of the working area with maximum efficiency, and the maximum linear speed of the vehicle with taking into account the gear ratio of the main transmission of its transmission, corresponding to the initial or final boundaries of the work zone electrical machines with maximum efficiency, according to the formula

where U _M is the gear ratio of the gear pair of the module, U _GP is the gear ratio of the main transmission of the vehicle’s transmission,

- boundary linear velocity,

- linear speed of the vehicle.

In the drawings:

figure 1 is an exemplary diagram of KEU using the proposed module for converting electricity, with rear-wheel drive vehicles;

figure 2 - power conversion module (circuit);

figure 3 - adder of moments (diagram);

figure 4 is a graph of the output of operating electric machines in the zone of effective efficiency.

The proposed KEU contains a drive shaft 1 of the drive wheel of the vehicle and the following components: a motor-generator unit 2, a universal unified module for converting electricity 3, an inverter 4 and energy storage buffers 5 and can be built on a modular principle, in which the listed components are made in the form of unified blocks that make up the optimal size range, which will help reduce the cost of manufacturing such plants while increasing maintainability due to t interchangeability nodes expansion layout DEs decision range.

, где U_M - передаточное число модуля, U_ГП - передаточное число главной передачи,

- граничная линейная скорость,

- линейная скорость транспортного средства.The electric power conversion module 3 consists of two traction motors with the same speed characteristics of electric machines 6 and 7 and not requiring external control of a mechanical moment accumulator 8, having its own housing 9 with input shafts 10 and 11 and an output shaft 12 arranged in parallel thereto, which is connected with shaft 1. Two parallel gear pairs 13 and 14 of constant gearing are made with different gear ratios, which are selected so that the speed range of the machines 6 and 7 would be l is consistent with the vehicle speed range. For each pair of gears, the gear ratio is determined by the ratio of the boundary linear speed corresponding to the angular velocity of the electric machine shaft, which defines the boundary of the working area with maximum efficiency, and the maximum linear speed of the vehicle, taking into account the gear ratio of the main transmission of its transmission, corresponding to the initial or final boundaries of the working area of electric machines with maximum efficiency according to the formula

where U _M is the gear ratio of the module, U _GP is the gear ratio of the main gear,

- boundary linear velocity,

- linear speed of the vehicle.

Module 3 is installed on the vehicle support system (not shown conventionally in the drawings) at the location of the drive wheels of the vehicle. Depending on the purpose, type, power parameters and dimensions of hybrid vehicles, the installation may contain one or more modules 3.

The universality of module 3 lies in the fact that by simply varying its characteristics, it is possible to achieve optimal and coordinated operation of electric machines of various types mounted in KEU for installation on vehicles of different classes and purposes. The proposed module can be used not only in KEU TS, but also as an independent drive unit in various industries.

The implementation and placement of the engine-generator unit 2 and its connection to the drive shaft of the drive wheels of the vehicle in this application is not regulated, because determined by reasonable feasibility in each specific design option KEU.

As follows from the diagram shown in figure 4, each electric machine has a zone of work with the highest efficiency, characterized by a certain range of frequencies of rotation of its shaft. When controlling the movement of the vehicle, its speed mode is divided into two conventional sections. Since machines 6 and 7 have the same speed range, each of these sections uses the same frequency range of electric machine shaft rotation, corresponding to the high efficiency zone of each electric machine, because the electric machine shafts are connected to the drive wheels of the vehicle through gears with different, but specially selected, gear ratios.

, определяемой граничной по параметру эффективности частотой вращения вала электромашины, работает та электрическая машина, которая передает крутящий момент на ведущие колеса ТС через зубчатую пару с большим передаточным числом, например, 6. При этом режим ее работы характеризуется высокими КПД, т.к. диапазон частот вращения вала электромашины, которому соответствует диапазон линейных скоростей от нулевой до

, согласован через передаточное число передающего устройства U_M1 со скоростным диапазоном транспортного средства. Как только скорость транспортного средства превышает граничную для первой части диапазона

, электромашина 6 отключается и в работу включается электромашина 7, связанная с ведущими колесами транспортного средства через зубчатое зацепление с меньшим передаточным числом U_M2. При этом она полностью реализует всю вторую часть скоростного диапазона ТС от граничной скорости

до максимальной для транспортного средства

. Режим ее работы при этом также характеризуется высокими КПД, т.к. частотный диапазон электромашины, которому соответствует диапазон линейных скоростей от

до

, также согласован через передаточное число передающего устройства со скоростным диапазоном транспортного средства. Таким образом, повышается общий КПД работы комбинированной энергетической установки.Electric machines are switched on in series: in the first section of the vehicle’s speed range, characterized by speeds from zero to the boundary for this section

that is determined by the rotational speed of the shaft of the electric machine, which is limited by the efficiency parameter, the electric machine that transmits the torque to the drive wheels of the vehicle through a gear pair with a large gear ratio, for example, 6. Moreover, its operation mode is characterized by high efficiency, because the frequency range of rotation of the shaft of an electric machine, which corresponds to a range of linear speeds from zero to

, matched through the gear ratio of the transmitter U _M1 with the speed range of the vehicle. As soon as the vehicle speed exceeds the boundary for the first part of the range

, the electric machine 6 is turned off and the electric machine 7 is connected to the operation, connected with the drive wheels of the vehicle through gearing with a lower gear ratio U _M2 . Moreover, it fully implements the entire second part of the vehicle speed range from the boundary velocity

to maximum for a vehicle

. The mode of its operation is also characterized by high efficiency, because the frequency range of the electric machine, which corresponds to a range of linear speeds from

before

, also matched through the gear ratio of the transmitting device with the speed range of the vehicle. Thus, the overall efficiency of the combined power plant is increased.

If it is necessary to ensure the required increased dynamics of the vehicle, both electric machines can be simultaneously switched on, thus maximizing the traction force on the drive wheels of the vehicle. In this case, it becomes possible to overcome the maximum resistance to movement by the vehicle. This result obtained significantly overlaps some likely deviation of the operation mode of electric machines from the most efficient one.

Thanks to the proposed solution of the electric power conversion module, which opens up new possibilities in creating combined power plants, it is achieved:

- simplification and cheapening of their designs;

- the ability to unify and typify the main components of the installation at a high level, to increase their reliability and maintainability;

- improving the efficiency of KEU by increasing the efficiency of its traction machines and reducing losses in the transmission.

The achieved improvement in the operational parameters of KEU contributes to the creation of hybrid vehicles at a higher quality level.

Implementation of the proposed group of inventions can reduce costs in the production of new models of hybrid vehicles, as well as the terms of putting them into production and subsequent manufacture due to the possibility of using the modular principle of building KEU.

It also allows you to get new models of hybrid vehicles of different classes by upgrading existing ones without a significant increase in capital costs only by replacing or rearranging the unified modules of the main components of the KEU, having established a separate, at least small-scale, production of such modules.

Claims (1)

An electric power conversion module of a combined power plant comprising two electric machines and a transmitting device in the form of a mechanical rotary moment adder having a housing in which two input shafts for connecting electric machines are placed in parallel, an output shaft for connecting the load and gear drives, characterized in that the electric machines are mounted on the adder case and are directly connected to its input shafts, and as gears the adder contains two pairs of gears of constant gearing tions formed with different values of gear ratios, gear ratio of each pair is determined by matching the frequency band of each electric machine with high-speed range of the vehicle.

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