阅读说明：本技术 增程器、控制方法及车辆 (Range extender, control method and vehicle ) 是由 马帅营 章帅 蔡文远 王一戎 霍元 于 2021-01-19 设计创作，主要内容包括：一种增程器、控制方法及车辆,该增程器包括发动机、飞轮、可变传动比增速器、发电机及控制单元,发动机的输出轴依次通过飞轮及可变传动比增速器与发电机相连。发动机被设置为在改变影响因素的参数的情况下,可使发动机的万有特性曲线内的低油耗高效区得以扩展,控制单元根据增程器的工况需求对发动机的实时转速和扭矩进行控制,并对发动机的万有特性曲线的影响因素的参数进行控制,使发动机的实时转速和扭矩落于发动机的低油耗高效区内,控制单元根据发动机的实时转速对可变传动比增速器进行控制,使得发动机经过可变传动比增速器输出的转速与发电机最高效率转速相同。该增程器能够始终工作于高效区内,且发电机始终能够运行于最高效率转速。(A range extender comprises an engine, a flywheel, a variable transmission ratio speed increaser, a generator and a control unit, wherein an output shaft of the engine is connected with the generator sequentially through the flywheel and the variable transmission ratio speed increaser. The engine is set to be under the condition of changing parameters of influencing factors, the low-oil-consumption efficient area in the universal characteristic curve of the engine can be expanded, the control unit controls the real-time rotating speed and the torque of the engine according to the working condition requirement of the range extender and controls the parameters of the influencing factors of the universal characteristic curve of the engine, the real-time rotating speed and the torque of the engine fall in the low-oil-consumption efficient area of the engine, the control unit controls the variable transmission ratio speed increaser according to the real-time rotating speed of the engine, and the rotating speed output by the engine through the variable transmission ratio speed increaser is the same as the highest-efficiency rotating speed of the generator. The range extender can always work in a high-efficiency area, and the generator can always operate at the highest-efficiency rotating speed.)

1. A range extender is characterized in that: the engine is set to expand a low-oil-consumption high-efficiency area in the universal characteristic curve of the engine under the condition of changing parameters of influencing factors, the control unit controls the real-time rotating speed and the torque of the engine according to the working condition requirement of the range extender and controls the parameters of the influencing factors of the universal characteristic curve of the engine, so that the real-time rotating speed and the torque of the engine fall into the low-oil-consumption high-efficiency area of the engine, and the control unit controls the variable transmission ratio speed increaser according to the real-time rotating speed of the engine, so that the engine output speed through the variable transmission ratio speed increaser is the same as the generator maximum efficiency speed.

2. The range extender of claim 1, wherein: the engine comprises a piston, a sliding groove and an electric control slider are arranged on the piston, the electric control slider is arranged in the sliding groove and moves up and down in the sliding groove to change the volume of a combustion chamber, and the control unit controls the volume of the combustion chamber of the engine to change the universal characteristics of the engine.

3. The range extender of claim 1, wherein: the engine comprises a first oil sprayer arranged on a cylinder cover and a second oil sprayer arranged in an air inlet channel, and the control unit is used for spraying fuels with the same or different characteristics to the first oil sprayer and the second oil sprayer so as to change the universal characteristics of the engine.

4. The range extender of claim 1, wherein: different parameters of influencing factors of the engine and corresponding data sets of the low-oil-consumption efficient area of the engine are stored in the control unit.

5. The range extender of claim 1, wherein: the variable transmission ratio speed increaser comprises an input shaft, an output shaft, a transmission belt and a driving device, wherein the input shaft and the output shaft are both conical shafts, the axes of the input shaft and the output shaft are parallel to each other, the transmission belt is arranged between the input shaft and the output shaft, and the control unit drives the transmission belt to move on the input shaft and the output shaft through the driving device so as to change the transmission ratio of the speed increaser.

6. A control method of a range extender is characterized by comprising the following steps:

s1: acquiring real-time speed and torque requirements of a vehicle;

s2: controlling the real-time rotating speed and the torque of the engine according to the vehicle speed and the torque demand, and changing the low-oil-consumption high-efficiency area of the engine according to the real-time rotating speed and the torque of the engine to enable the real-time rotating speed and the torque of the engine to fall into the low-oil-consumption high-efficiency area;

s3: and changing the transmission ratio of a variable transmission ratio speed increaser according to the highest-efficiency rotating speed of the generator and the real-time rotating speed of the engine, so that the rotating speed output by the engine after passing through the variable transmission ratio speed increaser is the same as the highest-efficiency rotating speed of the generator.

7. A vehicle, characterized in that: comprising a range extender according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of vehicle power systems, in particular to a range extender, a control method and a vehicle.

Background

Nowadays, the extended range electric vehicle is one of the mainstream technical routes of new energy vehicle power. The operating point of the range extender is in principle selected to be within the high efficiency region of the range extender, but in practice efficiency is not the only consideration: in order to take account of the NVH performance of the vehicle and the subjective feeling of drivers and passengers, the range-extended electric vehicle usually associates the speed, the rotating speed and the power, namely the speed is one of the selection bases of the working points of the range extender besides the rotating speed and the power; in addition, the SOC value of the power battery in the range-extended vehicle is also a factor for determining the operation point of the range extender. Therefore, the range extender inevitably has an operating point in a low rotation speed region, and as shown in fig. 1, the high-efficiency low-emission region of the engine is mostly in a medium rotation speed-medium high load region, which makes it impossible for the operating point of the engine (e.g., the point in fig. 1) to be in the low-fuel consumption high-efficiency region of the engine in the low rotation speed region, and likewise makes it impossible for the operating point of the range extender (e.g., the point in fig. 2) to be in the high-efficiency low-emission region. Due to the limitations of cost, volume and weight, the rated speed of the generator in the range extender is often higher, so that the high efficiency area of the generator is biased to high speed-high load, which is obviously different from the engine. When the range extender works, although a low-speed motor (such as about 4000rpm at the highest rotating speed) can be selected as much as possible, the high-efficiency areas of the engine and the generator are not just overlapped generally, so that the high-efficiency area of the range extender is narrow, and the highest efficiency is not high enough.

In order to improve the efficiency of the range extender, the high-efficiency regions of the engine and the generator should coincide with each other besides selecting the high-efficiency engine and the generator. In the prior art, a speed increaser is arranged between the engine and the generator, for example, the rotating speed of the engine is increased by the speed increaser so as to be matched with a high-efficiency area of the generator.

However, in the existing gear speed increasing scheme, the transmission ratio of the gear speed increasing device is fixed and unchangeable, so that the rotating speed of an engine can be just always coincided with the high-efficiency area of a generator after being matched with the speed increasing device, and the range increasing device cannot be ensured to always run in the high-efficiency area; even if the rotating speed of the engine is matched with the speed increasing of the speed increasing device to reach the rotating speed of the high-efficiency section of the generator, the generator cannot be guaranteed to work at the highest-efficiency rotating speed.

Disclosure of Invention

The invention provides a range extender, a control method and a vehicle.

The invention provides a range extender, which comprises an engine, a flywheel, a variable transmission ratio speed increaser, a generator and a control unit, wherein an output shaft of the engine is connected with the generator sequentially through the flywheel and the variable transmission ratio speed increaser, the control unit is electrically connected with the engine, the variable transmission ratio speed increaser and the generator, the engine is set to expand a low-oil-consumption high-efficiency area in a universal characteristic curve of the engine under the condition of changing parameters of influencing factors, the control unit controls the real-time rotating speed and the torque of the engine according to the working condition requirement of the range extender and controls the parameters of the influencing factors of the universal characteristic curve of the engine to enable the real-time rotating speed and the torque of the engine to fall into the low-oil-consumption high-efficiency area of the engine, and the control unit controls the variable transmission ratio speed increaser according to the real-time rotating speed of the engine, so that the engine output speed through the variable transmission ratio speed increaser is the same as the generator maximum efficiency speed.

Further, the engine comprises a piston, a sliding groove and an electric control slider arranged in the sliding groove are arranged on the piston, the electric control slider moves up and down in the sliding groove to change the volume of the combustion chamber, and the control unit controls the volume of the combustion chamber of the engine to change the universal characteristics of the engine.

Furthermore, the engine comprises a first oil injector arranged on a cylinder cover and a second oil injector arranged in an air inlet channel, and the control unit is used for injecting fuels with the same or different characteristics to the first oil injector and the second oil injector so as to change the universal characteristics of the engine.

Furthermore, different parameters of influencing factors of the engine and corresponding data sets of the low-oil-consumption efficient area of the engine are stored in the control unit.

Further, the variable transmission ratio speed increaser comprises an input shaft, an output shaft, a transmission belt and a driving device, wherein the input shaft and the output shaft are both conical shafts, the axes of the input shaft and the output shaft are parallel to each other, the transmission belt is arranged between the input shaft and the output shaft, and the driving device drives the transmission belt to move on the input shaft and the output shaft.

The invention also provides a control method of the range extender, which comprises the following steps:

s1: acquiring real-time speed and torque requirements of a vehicle;

s2: controlling the real-time rotating speed and the torque of the engine according to the vehicle speed and the torque demand, and changing the low-oil-consumption high-efficiency area of the engine according to the real-time rotating speed and the torque of the engine to enable the real-time rotating speed and the torque of the engine to fall into the low-oil-consumption high-efficiency area;

s3: and changing the transmission ratio of a variable transmission ratio speed increaser according to the highest-efficiency rotating speed of the generator and the real-time rotating speed of the engine, so that the rotating speed output by the engine after passing through the variable transmission ratio speed increaser is the same as the highest-efficiency rotating speed of the generator.

The invention further provides a vehicle which comprises the range extender.

In summary, in the present invention, through the expansion of the low fuel consumption high efficiency region of the engine and the control of the transmission ratio of the variable transmission ratio speed increaser, the engine can always work in the low fuel consumption high efficiency region, after the engine and the generator are combined, all the working points in the range extender can fall in the low fuel consumption high efficiency region of the range extender, and the generator can always work at the highest efficiency rotation speed. This can significantly improve the efficiency of the range extender, reduce emissions, and reduce the exhaust aftertreatment cost of the range extender.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the technical solutions can be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

Fig. 1 is a graph showing the characteristics of an engine in the prior art.

Fig. 2 is a graph showing the characteristics of a conventional range extender.

Fig. 3 is a schematic structural diagram of a range extender according to a first embodiment of the present invention.

Fig. 4 is a graph showing all characteristic curves of the engine shown in fig. 3.

Fig. 5 is a graph showing all characteristic curves of the generator of fig. 3.

Fig. 6 is a universal characteristic curve diagram of the range extender provided by the present invention.

Fig. 7 is a schematic diagram showing the structure of a variable compression ratio engine.

Fig. 8 is a schematic view of a variable transmission.

Fig. 9 is a schematic structural view of a multiple injector engine according to a second embodiment of the invention.

Detailed Description

To further explain the technical means and effects of the present invention adopted to achieve the predetermined objects, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

The invention provides a range extender, a control method and a vehicle with the range extender.

Fig. 3 is a schematic structural diagram of a range extender according to a first embodiment of the present invention, fig. 4 is a graph showing all characteristic curves of the engine in fig. 3, fig. 5 is a graph showing all characteristic curves of the generator in fig. 3, and fig. 6 is a graph showing all characteristic curves of the range extender according to the present invention. As shown in fig. 3 to 6, the range extender provided by the present invention includes an engine 10, a flywheel 20, a variable transmission ratio speed increaser 30, a generator 40 and a control unit 50, wherein an output shaft of the engine 10 is connected to the generator 40 sequentially through the flywheel 20 and the variable transmission ratio speed increaser 30, the control unit 50 is electrically connected to the engine 10, the variable transmission ratio speed increaser 30 and the generator 40, in this embodiment, the engine 10 is configured such that a low-efficiency region in a universal characteristic curve of the engine 10 can be expanded while parameters of influencing factors are changed; the control unit 50 controls the real-time rotating speed and the torque of the engine 10 according to the working condition of the range extender, and controls parameters of influencing factors of a universal characteristic curve of the engine 10, so that the real-time rotating speed and the torque of the engine 10 enter a low-oil-consumption high-efficiency area of the engine 10; the control unit 50 then controls the transmission ratio of the variable transmission ratio increaser 30 according to the real-time rotation speed of the engine 10 so that the rotation speed of the engine 10 output through the variable transmission ratio increaser 30 is the same as the maximum efficiency rotation speed of the generator 40.

The characteristic curves of the engine 10 are determined according to its parameters, and generally speaking, the characteristic curves of the engine 10 are not changed after the parameters are determined. In the present embodiment, by setting engine 10 such that the fuel efficiency region in the characteristic curve is expanded in the event of a change in the parameter of the influencing factor, it is possible to change the ranges of the rotation speed and the torque corresponding to the fuel efficiency region of engine 10 in the event of a change in the parameter of the influencing factor of engine 10. That is, different parameters may cause the low fuel consumption efficient region of engine 10 to have different speed and torque ranges after changing the parameters that affect the factors. Fig. 4 is a general graph showing the fuel efficiency ranges corresponding to a plurality of parameters superimposed, and it can be seen from fig. 4 that the engine 10 can fall into the fuel efficiency range corresponding to a certain parameter even at a low speed and a low torque by changing the parameters of the influencing factors. That is, this corresponds to the fact that the fuel economy efficient region of the engine 10 is expanded to the low rotation speed low torque region. As shown in fig. 4, the points representing the operating conditions of the engine 10 fall within the fuel efficiency region of the engine 10, which can indicate that the range extender provided in the present embodiment can operate the engine 10 in the fuel efficiency region of the engine 10 itself regardless of the operating conditions. Preferably, the control result of the parameters of the influencing factors is such that, in the universal characteristic curve of the engine 10, the rotation speed corresponding to the low fuel consumption efficient region of the engine 10 is significantly expanded (e.g. at least spans 1000rpm to 3500rpm), so that the engine 10 can still fall into the low fuel consumption efficient region of the engine 10 under the working condition of low rotation speed.

Further, as shown in fig. 5, in the same range extender, the high efficiency region of the generator 40 is determined, and therefore, the maximum efficiency rotation speed of the generator 40 is also a determined rotation speed, the dotted line in fig. 5 represents a torque interval corresponding to the maximum efficiency rotation speed of the engine 10, and after the rotation speed of the engine 10 is determined, the control unit 50 may change the transmission ratio of the variable transmission ratio gearbox 30 so that the rotation speed output after the engine 10 is combined with the variable transmission ratio gearbox 30 is the same as the maximum efficiency rotation speed of the generator 40, which enables the generator 40 to always operate at the maximum efficiency rotation speed. Furthermore, since the rotational speed of the engine 10 and the output of the variable transmission ratio speed-increasing gear 30 is controllable, the generator 40 does not need to select the low-speed generator 40 intentionally, and a high-speed generator 40 with more energy saving and smaller size can be used. In the present embodiment, the high efficiency region of the generator 40 corresponds to a relatively high speed (e.g., 4000rpm to 10000rpm), and the maximum efficiency speed is approximately 7000rpm to 8000rpm, preferably 7500 rpm.

That is, through the expansion of the low-fuel efficient area of the engine 10 and the control of the transmission ratio of the variable transmission ratio speed increaser 30, the engine 10 can always work in the low-fuel efficient area, and after the engine 10 and the generator 40 are combined, as shown in fig. 6, all the working points in the range extender can fall in the low-fuel efficient area of the range extender, and the generator can always work at the highest efficiency rotating speed. This can significantly improve the efficiency of the range extender, reduce emissions, and reduce the exhaust aftertreatment cost of the range extender.

Fig. 7 is a schematic diagram showing the structure of a variable compression ratio engine, and as shown in fig. 7, in the present embodiment, the influence factor of the change of the characteristic curve of the engine 10 may be the compression ratio, and accordingly, the engine 10 is the variable compression ratio engine 10. Specifically, the engine 10 includes a piston 61, a sliding groove 63 is provided in the piston 61, and an electronically controlled slider 62 is provided in the sliding groove 63, and the electronically controlled slider 62 is movable up and down in the sliding groove 63 to change the volume of the combustion chamber.

For low speed, low torque operating points of engine 10, engine 10 efficiency is increased by increasing its compression ratio. For the working condition points with high rotating speed and high torque, the compression ratio is kept unchanged or slightly improved, so that the engine 10 can be guaranteed to be efficient and knock can be inhibited (the knock is easily caused by overhigh compression ratio under the working condition of high rotating speed and high torque), and the knock inhibition and the efficiency improvement of the engine 10 under the full working condition are realized.

The operating principle of the engine 10 for changing the compression ratio is: when the engine 10 needs to increase the compression ratio, the electronically controlled slider 62 in its piston 61 moves upward a certain distance along the sliding groove 63 under the control of the control unit 50, thereby reducing the volume of the combustion chamber at the compression end (top dead center). Similarly, when the engine 10 needs to reduce the compression ratio, the electronically controlled slider 62 can be controlled by its control unit 50 to move a certain distance down the sliding groove 63, thereby increasing the volume of the combustion chamber at the end of the compression of the piston 61.

Fig. 8 is a schematic view of a variable transmission. As shown in fig. 8, the variable transmission ratio speed increaser 30 includes an input shaft 31, an output shaft 32, a transmission belt 33 and a driving device 34, wherein the input shaft 31 and the output shaft 32 are both conical shafts, and the axes thereof are arranged in parallel, the transmission belt 33 is arranged between the input shaft 31 and the output shaft 32, and the driving device 34 drives the transmission belt 33 to move on the input shaft 31 and the output shaft 32. The position of the belt 33 on the input shaft 31 and the output shaft 32 can be changed by the drive of the drive device 34 to change the transmission ratio. It will be appreciated that, being the speed increaser 30, its ratio can always be greater than 1 by controlling the range of movement of the drive belt 33.

After obtaining the real-time rotation speed of the engine 10, the control unit 50 may obtain the transmission ratio of the variable transmission ratio step-up gear 30 according to the maximum efficiency rotation speed of the generator 40 and the real-time rotation speed of the engine 10, and control the driving device to change the transmission ratio so that the rotation speed output after the engine 10 and the variable transmission ratio step-up gear 30 are combined is the same as the maximum efficiency rotation speed of the generator 40.

Further, in the present embodiment, the flywheel 20 may be a dual-mass flywheel or a single-mass flywheel, and when it is a single-mass flywheel, the flywheel 20 may further include a torsional vibration damper.

Fig. 9 is a schematic diagram showing the structure of a multi-injector engine according to a second embodiment of the present invention, and as shown in fig. 9, the second embodiment of the present invention is substantially the same as the first embodiment, except that in this embodiment, the influence factor of the change in the characteristic curve of engine 10 may be the type and injection strategy of the injected fuel, and accordingly, engine 10 includes first injector 71 disposed in the cylinder head of engine 10, and second injector 72 disposed in intake passage 73. It is to be understood that there may be a plurality of second fuel injectors 72, and in the present embodiment, there may be one or two.

The same fuel or different fuel injections may be performed while changing the characteristic of engine 10. When injecting different fuels, the control unit 50 controls the first injector 71 and the second injector 72 to inject fuels with different characteristics, for example, the first injector 71 injects fuel with a high octane number, and the second injector 72 injects fuel with a high cetane number. When the engine 10 works, for example, at a medium-low rotation speed and a medium-low load, a mixed fuel injection strategy of the first fuel injector 71 and the second fuel injector 72 is adopted, and the advantages of both the injection of the air inlet channel 73 and the in-cylinder direct injection are achieved, so that the fuel consumption of the engine 10 can be reduced, the high-efficiency area of the engine 10 is obviously expanded to a low-speed low-torque area, and the particulate matter emission at the medium-low rotation speed is reduced.

It is understood that in other embodiments, the engine 10 can have both the structures of the first and second embodiments.

The invention also provides a control method based on the range extender, which comprises the following steps:

s1: acquiring real-time speed and torque requirements of a vehicle;

s2: controlling the real-time rotating speed and the torque of the engine 10 according to the vehicle speed and the torque demand of the vehicle, and changing the low-oil-consumption high-efficiency area of the engine 10 according to the real-time rotating speed and the torque of the engine 10 to enable the real-time rotating speed and the torque of the engine 10 to fall into the low-oil-consumption high-efficiency area;

s3: the transmission ratio of the variable transmission ratio speed-increasing gearbox 30 is changed according to the maximum efficiency rotation speed of the generator 40 and the real-time rotation speed of the engine 10, so that the rotation speed output by the engine 10 after passing through the variable transmission ratio speed-increasing gearbox 30 is the same as the maximum efficiency rotation speed of the generator 40.

In the present embodiment, the change of the low fuel consumption and high efficiency region of engine 10 may be accomplished by changing the parameters that affect the characteristic curve of engine 10. The parameters of the characteristic influencing factors and the corresponding data set of the low-fuel consumption high-efficiency area can be obtained through a previous experiment and stored in the control unit 50.

Similarly, the characteristic curves of the generator 40 may be obtained by testing in advance, and stored in the control unit 50 to be recalled when used.

The invention further provides a vehicle, which comprises the range extender, and other technical characteristics of the vehicle are referred to in the prior art and are not described again.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.