Heavy transport vehicle distributed hybrid power system and power switching method
Technical Field
The invention relates to a distributed hybrid power system of a heavy transport vehicle and a power switching method, belonging to the technical field of vehicle power.
Background
The existing heavy transport vehicle has a single driving mode, the driving power mainly depends on a single power fuel engine in a tractor and is limited by the fuel quality and the engine structure principle, the space for further improving the driving power of the engine by improving the fuel characteristics is very small, compared with the development trend that modern transportation is gradually enlarged and heavy, and the technical requirements of the transport vehicle on a high-power and high-reliability driving system are more and more remarkable. For example, in the field of military vehicles and mine vehicles, the required transport capacity reaches several hundred tons, so that the pure improvement of fuel quality or the change of an engine structure can hardly be realized.
Heavy transport vehicles are about one hundred times as powerful as ordinary vehicles, and their energy consumption and exhaust emissions are also very alarming, and the problem of increased pollution caused by them is not negligible. If the vehicle thermal efficiency and the exhaust emission can be improved while the power is increased, the comprehensive benefits are very considerable.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a distributed hybrid power system of a heavy transport vehicle and a power switching method, which can ensure larger power, improve the fuel economy of the vehicle, reduce the oil consumption and reduce the pollution.
In order to achieve the purpose, the invention adopts the technical scheme that: a distributed hybrid power system of a heavy transport vehicle comprises a tractor driving system and a trailer driving system;
the tractor driving system comprises a tractor driver, a tractor motor, a coupling device, a gearbox, a tractor engine, a driving axle, driving wheels, a battery pack system and a vehicle control unit ECU (electronic control Unit), wherein the driving axle, the tractor motor and the gearbox are all connected with the coupling device;
the trailer driving system comprises a battery pack system, a generator, a trailer engine, a trailer controller and a hub motor, wherein the trailer engine is electrically connected with the generator, the generator and the trailer controller are electrically connected with the battery pack system, and the trailer controller is electrically connected with the hub motor; the battery pack system, the generator, the trailer engine and the trailer controller are all electrically connected with the ECU of the whole vehicle controller.
Furthermore, the number of the hub motors is not less than two, the number of the trailer controllers is equal to that of the hub motors, and each trailer controller is electrically connected with one hub motor.
Furthermore, the in-wheel motors are distributed on the left side and the right side of the trailer, the quantity of the two sides is equal, and the trailer controllers connected with the in-wheel motors on each side are sequentially connected in series.
Furthermore, the trailer driving system adopts a hub motor and adopts a brushless direct current hub motor controller as a trailer controller to regulate and control the hub motor.
A heavy transport vehicle power switching method, the heavy transport vehicle power divide into four kinds of drive modes, it is the drive mode of the starting phase, no-load phase drive mode, light, middle load phase drive mode, heavy load phase drive mode separately;
firstly, an accelerator pedal position sensor of a vehicle control unit ECU acquires a driver pedal opening signal and converts the driver pedal opening signal into a 0-100% accelerator pedal opening signal, a table is looked up according to the accelerator pedal opening signal and a vehicle speed signal to obtain a driver required torque T1, then the vehicle control unit ECU calculates an increased assistance required torque T2 according to the accelerator pedal opening, the accelerator pedal opening change rate and a power battery SOC value, and the sum of the driver required torque T1 and the increased assistance required torque T2 is the total driver required torque T; in the tractor driving system, the maximum driving torque of a tractor motor is T3, the range of 18% of the lower limit of the most efficient working point of the tractor engine is used as the efficient working area of the tractor engine, namely the lower limit rotating speed value N1 and the upper limit rotating speed value N2 of the efficient working area of the tractor engine can be determined, as the rated power of the tractor engine is fixed, the rotating speed of the tractor engine is inversely proportional to the torque, the lower limit torque T4 and the upper limit torque T5 corresponding to the efficient working area of the tractor engine can be obtained by the formula P which is k tau N, P is the rated power of the tractor engine, N is the rotating speed of the tractor engine, tau is the torque of the tractor engine, and k is a constant, because the corresponding working mode at this time is only driven by the tractor engine alone, the torque of the tractor engine at this;
when the total driver required torque T meets T < T4, the ECU of the whole vehicle controller is switched to a driving mode in a starting stage; when the total torque T required by the driver meets the condition that T is more than or equal to T4 and less than or equal to T5, the ECU of the whole vehicle controller is switched to a no-load stage driving mode; when the total driver demand torque T meets the condition that T5 is less than or equal to T (T3+ T5), the ECU of the whole vehicle controller is switched to a light-load and medium-load stage driving mode; when the driver total required torque T satisfies T > (T3+ T5), the vehicle controller ECU switches to the heavy-load phase drive mode.
Compared with the prior art, the power driving device is arranged on the tractor, the power driving device is arranged on the trailer, the driving devices arranged on the tractor and the trailer are hybrid driving devices, and the whole vehicle driving system has the characteristics of multi-point arrangement and multi-source hybrid power, can generate power which is larger and more reliable than that of a single tractor driving system, overcomes the problem of insufficient power caused by single power system of a heavy transport vehicle, and greatly improves the carrying capacity of the heavy transport vehicle; the distributed hybrid power drive is adopted, so that the advantages of long continuous working time and good dynamic property of the engine are exerted, the advantages of no pollution and low noise of the motor can be exerted, the advantages of the engine and the motor are made up for each other, the thermal efficiency of the automobile can be improved by more than 10%, and the exhaust emission can be improved by more than 30%. Therefore, the system can meet the environmental protection requirements of improving fuel economy, reducing oil consumption and reducing pollution while meeting the power requirement of increasing vehicle power.
Drawings
FIG. 1 is a schematic structural view of the present invention;
in the figure: 1. the system comprises a tractor driver, 2, a tractor motor, 3, a coupling device, 4, a gearbox, 5, a tractor engine, 6, a drive axle, 7, a drive wheel, 8, a battery pack system, 9, a vehicle control unit ECU, 10, a generator, 11, a trailer engine, 12, a trailer controller, 13 and a hub motor.
Detailed Description
The invention will be further explained with reference to the drawings.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the present invention includes a tractor drive system and a trailer drive system;
the tractor driving system comprises a tractor driver 1, a tractor motor 2, a coupling device 3, a gearbox 4, a tractor engine 5, a drive axle 6, a driving wheel 7, a battery pack system 8 and a vehicle control unit ECU9, wherein the battery pack system 8 consists of a plurality of battery packs;
the drive axle 6, the tractor motor 2 and the gearbox 4 are all connected with the coupling device 3, the tractor driver 1 is connected with the tractor motor 2, the tractor engine 5 is connected with the gearbox 4, two ends of the drive axle 6 are connected with the drive wheel 7, and the tractor driver 1 and the tractor engine 5 are both electrically connected with the whole vehicle controller ECU 9; the tractor driving system is a main source of vehicle power, and the power is strong enough, so the tractor driving system is driven by parallel hybrid power.
The trailer driving system comprises a battery pack system 8, a generator 10, a trailer engine 11, a trailer controller 12 and a hub motor 13, wherein the trailer engine 11 is electrically connected with the generator 10, the generator 10 and the trailer controller 12 are both electrically connected with the battery pack system 8, and the trailer controller 12 is electrically connected with the hub motor 13;
the battery pack system 8, the generator 10, the trailer engine 11 and the trailer controller 12 are electrically connected with the whole vehicle controller ECU 9; the number of the in-wheel motors 13 is even number not less than two, the number of the trailer controllers 12 is equal to that of the in-wheel motors 13, each trailer controller 12 is electrically connected with one in-wheel motor 13, the in-wheel motors 13 are distributed on the left side and the right side of the trailer, the number of the two sides is equal, and the trailer controllers 12 connected with the in-wheel motors 13 on each side are sequentially connected in series; the trailer driving system is used as a vehicle auxiliary driving system, aims to provide auxiliary power, simultaneously has simple structure and low cost, and has simpler structure and control of a series hybrid power.
The power of the invention is divided into four driving modes and can realize automatic switching under different conditions:
the first driving mode is driven by only the tractor motor 2, namely, the battery pack system 8 drives the tractor motor 2 through the tractor driver 1, and then drives the driving wheel 7 through the coupling device 3 and the driving axle 6 to realize driving, and the tractor engine 5 and the trailer driving system are in a non-operating state;
the second drive mode is driven by the tractor engine 5 only, i.e. the tractor engine 5 transmits power to the tractor through the gearbox 4 and the coupling device 3, while the tractor motor 2 and the trailer drive system are in an inactive state;
the third driving mode is that the tractor engine 5 and the tractor motor 2 are driven together, namely the battery pack system 8 drives the tractor motor 2 through the tractor driver 1 and then provides power for the tractor together with the engine 5 through the coupling device 3, and the trailer driving system is in a non-operating state;
the fourth driving mode is that the tractor engine 5 and the tractor motor 2 are driven together, and simultaneously, the trailer engine 11 and the generator 10 in the trailer driving system are driven in series, namely, in the third driving mode, the trailer engine 11 directly drives the generator 10 to generate electricity, the electric energy is transmitted to the battery pack system 8, the battery pack system 8 sequentially transmits the electric power to each hub motor 14 through the controller 12 to realize trailer driving, and at the moment, the tractor driving system and the trailer driving system are both in a working state.
The first mode is suitable for the starting stage of the heavy transport vehicle; the second mode is suitable for the no-load stage of the heavy transport vehicle; the third mode is suitable for light and medium load stages of the heavy transport vehicle; the fourth mode is suitable for heavy-duty phases of heavy-duty transport vehicles.
When the heavy transport vehicle brakes and decelerates, the tractor motor 2 can be used as a generator to convert the lost kinetic energy into electric energy to be stored in a battery pack system; during actual operation, firstly, an accelerator pedal position sensor of the vehicle control unit ECU9 collects a driver pedal opening degree signal and converts the driver pedal opening degree signal into a 0-100% accelerator pedal opening degree signal, a table is searched according to the accelerator pedal opening degree signal and a vehicle speed signal to obtain a driver required torque T1, then the vehicle control unit ECU9 calculates an increased assistance required torque T2 according to the accelerator pedal opening degree, the accelerator pedal opening degree change rate and the power battery SOC value, and the sum of the driver required torque T1 and the increased assistance required torque T2 is the total driver required torque T. In the tractor driving system, the maximum driving torque of a tractor motor 2 is T3, a section of flat cement pavement or asphalt pavement without gradient is selected, heavy vehicles respectively run at constant speed at different speeds (one point can be obtained every 10 km/h) of the highest gear for the section of the route, the average value is obtained by going back and forth once (the influence of wind and gradient is eliminated), the oil consumption is recorded, the fuel consumption of the heavy vehicles at different speeds can be obtained, namely the fuel consumption at the hundred kilometers of the heavy vehicles at the same speed is called as constant speed, the rotating speed of the highest effective working point of the tractor engine 5 can be determined by comparing the fuel consumption at the hundred kilometers at the same speed, the range of 18 percent of the lower limit of the highest effective working point of the tractor engine 5 is taken as the high-efficiency working area of the engine 5, the lower limit rotating speed value N1 and the upper limit rotating speed value N2 of the high, the rotating speed of the tractor engine 5 is inversely proportional to the torque, a formula P is k τ N, P is the rated power of the tractor engine 5, N is the rotating speed of the tractor engine 5, τ is the torque of the tractor engine 5, k is a constant, for each engine, the value of the constant is fixed, and the lower limit torque T4 and the upper limit torque T5 corresponding to the efficient working area of the tractor engine 5 can be obtained, because only the tractor engine 5 is driven independently in the corresponding working mode at the moment, the torque of the tractor engine 5 at the moment is the total torque T required by the driver;
when the total driver required torque T meets T < T4, the vehicle control unit ECU9 switches to a first driving mode; when the total driver required torque T meets the condition that T is more than or equal to T4 and less than or equal to T5, the whole vehicle controller ECU9 is switched to a second driving mode; when the total driver required torque T meets the condition that T5 is less than T and less than or equal to (T3+ T5), the ECU9 of the whole vehicle controller is switched to a third driving mode; when the driver total required torque T satisfies T > (T3+ T5), the vehicle controller ECU9 switches to the fourth drive mode. In the mode switching process, the ECU9 of the vehicle controller filters signals of an accelerator pedal, unnecessary signal peaks can be removed from the filtered signals, so that the effect of inhibiting the mode from being frequently switched is achieved, meanwhile, the power source control in each mode still adopts unfiltered signals of the accelerator pedal so as to ensure the good power response characteristic of the vehicle, and the heavy transport vehicle can obtain the excellent driving performance with the requirements on environmental protection, economy and power.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any minor modifications, equivalent replacements and improvements made to the above embodiment according to the technical spirit of the present invention should be included in the protection scope of the technical solution of the present invention.