A method for testing the efficiency of a hybrid electric drive assembly of a vehicle

Abstract

The present invention discloses an efficiency testing method for a vehicle hybrid electric drive assembly, which relates to the field of vehicle testing technology and includes the following steps: Step S10, obtaining a preset test condition of a target vehicle, and performing a bench test on the hybrid electric drive assembly of the target vehicle according to the preset test condition; Step S20, obtaining the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, as well as the current and voltage output by a battery simulator during the bench test; Step S30, calculating the efficiency of the hybrid electric drive assembly of the target vehicle based on the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, as well as the current and voltage of the battery simulator. The present invention comprehensively considers the various input energies and output energies of the hybrid electric drive assembly, and the efficiency test results are more accurate and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle testing, and in particular to an efficiency testing method for a hybrid electric drive assembly of a vehicle. Background Art

[0002] Currently, a hybrid vehicle (HEV) refers to a vehicle whose drive system is composed of two or more simultaneously operating individual drive systems. Hybrid power combines the advantages of an engine's long operating time and high power with the pollution-free and low-noise properties of an electric motor. By combining these two strengths and complementing each other, the vehicle's thermal efficiency can be increased by over 10% and exhaust emissions can be improved by over 30%. The development of HEVs is one of the future trends in automotive development. The efficiency of a HEV's hybrid electric drive system is a key indicator for evaluating and influencing fuel economy.

[0003] In the prior art, a common method for testing the efficiency of a hybrid electric drive assembly is bench testing. However, bench testing generally uses fixed operating conditions, speed, and torque for each power source to perform sweep point testing to obtain the power at the input and output ends to calculate the efficiency. This method does not fully consider the energy input and output during the test process and has limitations, resulting in inaccurate efficiency test results. Summary of the Invention

[0004] An embodiment of the present invention provides an efficiency testing method for a vehicle hybrid electric drive assembly to address the technical problems in the related art of the efficiency testing method for a vehicle hybrid electric drive assembly, such as the limitations on the consideration of input and output energy and the inaccurate efficiency test results.

[0005] An embodiment of the present invention provides a method for testing the efficiency of a hybrid electric drive assembly of a vehicle, comprising the following steps:

[0006] Obtaining a preset test condition of a target vehicle, and performing a bench test on a hybrid electric drive assembly of the target vehicle according to the preset test condition;

[0007] Obtaining the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor during the bench test, as well as the current and voltage of the battery simulator;

[0008] The efficiency of the hybrid electric drive assembly of the target vehicle is calculated based on the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, as well as the current and voltage of the battery simulator.

[0009] In some embodiments, the step of calculating the efficiency of the hybrid electric drive assembly of the target vehicle based on the speed and torque of the output terminal of the test bench input dynamometer motor and the test bench output dynamometer motor and the current and voltage of the battery simulator includes:

[0010] According to the speed and torque of the output end of the test bench input dynamometer motor and the input end of the test bench output dynamometer motor, as well as the current and voltage of the battery simulator, the energy E1 output by the hybrid electric drive assembly to the test bench output end, the energy E2 output to the battery simulator, the energy E3 output to the test bench input end, the energy E4 input by the battery simulator to the hybrid electric drive assembly, the energy E5 input from the test bench input end to the hybrid electric drive assembly, and the energy E6 input from the test bench output end to the hybrid electric drive assembly are calculated.

[0011] Then according to the formula Calculate the efficiency of the hybrid electric drive system of the target vehicle.

[0012] In some embodiments, the step of obtaining the rotational speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, as well as the current and voltage of the battery simulator during the bench test, further includes:

[0013] Obtain the speed and torque of the generator and drive motor of the hybrid electric drive system during bench testing;

[0014] Analyze the speed and torque of the output end of the test bench input dynamometer in the engine map, analyze the speed and torque of the drive motor in the drive motor map, and analyze the speed and torque of the generator in the generator map.

[0015] Based on the analysis results, the structural parameters and control strategies of the hybrid electric drive assembly of the target vehicle are optimized.

[0016] In some embodiments, the step of analyzing the locations of the speed and torque of the output end of the test bench input dynamometer motor in the engine map includes:

[0017] The engine optimization working area is determined based on the relative position of the speed and torque of the output end of the test bench input dynamometer motor in the engine map and the engine optimal line.

[0018] In some embodiments, the step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle based on the analysis results includes:

[0019] When the engine of the hybrid electric drive assembly of the target vehicle actually operates in the engine optimization operating area, the torque distribution ratio of the engine in the hybrid electric drive assembly is reduced and the torque distribution ratio of the drive motor is increased, or the engine is controlled to stop working.

[0020] In some embodiments, the step of analyzing the locations of the speed and torque of the drive motor in the drive motor map includes:

[0021] The optimized working area of ​​the drive motor is determined according to the landing point of the speed and torque of the drive motor in the drive motor map.

[0022] In some embodiments, the step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle based on the analysis results includes:

[0023] When the drive motor of the hybrid electric drive assembly of the target vehicle actually operates in the drive motor optimization working area, the output gear position of the drive motor of the hybrid electric drive assembly is adjusted.

[0024] In some embodiments, the step of analyzing the locations of the generator speed and torque in the generator map includes:

[0025] The generator's optimized working area is determined based on the generator's speed and torque in the drive motor map.

[0026] In some embodiments, the step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle based on the analysis results includes:

[0027] Adjust the speed ratio between the engine and the generator.

[0028] In some embodiments, the preset test condition is a CHTC condition.

[0029] The beneficial effects brought about by the technical solution provided by the present invention include:

[0030] An embodiment of the present invention provides an efficiency testing method for a vehicle hybrid electric drive assembly. First, a preset test condition of a target vehicle is obtained, and the hybrid electric drive assembly of the target vehicle is bench tested according to the preset test condition. Then, the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, as well as the current and voltage of a battery simulator, are obtained during the bench test. Finally, the efficiency of the hybrid electric drive assembly of the target vehicle is calculated based on the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, as well as the current and voltage of the battery simulator. The present invention comprehensively considers various input energies and output energies, and the efficiency test results are more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A flow chart of a method for testing the efficiency of a hybrid electric drive assembly of a vehicle provided by an embodiment of the present invention;

[0033] Figure 2 A block diagram of the principles of bench testing provided by an embodiment of the present invention;

[0034] Figure 3 A schematic diagram showing the engine speed and torque at different vehicle speeds projected onto an engine map according to an embodiment of the present invention;

[0035] Figure 4 A schematic diagram showing the locations of the speed and torque of the drive motor at different vehicle speeds projected onto a drive motor map provided by an embodiment of the present invention;

[0036] Figure 5 Another schematic diagram of the projection of the rotational speed and torque of the drive motor at different vehicle speeds on the drive motor map provided by an embodiment of the present invention;

[0037] Figure 6 A schematic diagram showing the rotational speed and torque of a generator at different vehicle speeds projected onto a generator map according to an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the generator map diagram where the rotational speed and torque of the generator are projected onto the generator map at different planetary gear K values ​​and different vehicle speeds according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0040] An embodiment of the present invention provides an efficiency testing method for a vehicle hybrid electric drive assembly, which can solve the technical problems of existing vehicle hybrid electric drive assembly efficiency testing methods, such as limitations on consideration of input and output energy and inaccurate efficiency test results.

[0041] See also Figure 1 As shown, an embodiment of the present invention provides a method for testing the efficiency of a vehicle hybrid electric drive assembly, comprising the following steps:

[0042] Step S10: obtaining a preset test condition of the target vehicle, and performing a bench test on the hybrid electric drive assembly of the target vehicle according to the preset test condition.

[0043] Specifically, the preset test condition can be the CHTC condition, which is an improvement on the C-WTVC (China World Transient Vehicle Cycle). The CHTC condition is suitable for energy consumption testing of heavy-duty hybrid and electric vehicles. It is also the standard duty cycle for fuel consumption certification of heavy-duty commercial vehicles. The CHTC condition test can more accurately assess the vehicle's fuel economy and energy consumption in actual use.

[0044] Step S20 , obtaining the rotational speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor as well as the current and voltage of the battery simulator during the bench test.

[0045] Specifically, Figure 2 This is the principle block diagram of the bench test. The bench is equipped with a battery simulator, temperature controller, data acquisition sensor, vehicle controller, bench main control computer, etc. The hybrid electric drive assembly comes with its own motor controller and transmission controller.

[0046] The hybrid electric drive assembly of the target vehicle is installed on the test bench, keeping the posture consistent with that of the whole vehicle. The test bench input dynamometer motor simulates the target vehicle's engine to provide power input, the battery simulator simulates the target vehicle's battery to provide and store electrical energy for the hybrid electric drive assembly, and the test bench output dynamometer motor simulates the energy absorbed and output by the road.

[0047] The test bench CAN signal inputs the CHTC cycle working condition to the test bench input dynamometer motor, the test bench CAN signal controls the drive motor and generator of the hybrid electric drive assembly, the test bench CAN signal controls the battery simulator to simulate the battery of the target vehicle, and the test bench CAN signal sends gear information to simulate the driver controlling the throttle and brake. During the test, the motor controller, motor, etc. are cooled, and the cooling flow and temperature are consistent with those of the whole vehicle. The output end of the test bench input dynamometer motor and the input end of the test bench output dynamometer motor collect speed and torque through sensors, and the battery simulator collects current and voltage through sensors.

[0048] Step S30 , calculating the efficiency of the hybrid electric drive assembly of the target vehicle based on the rotational speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor and the current and voltage of the battery simulator.

[0049] Specifically, the step of calculating the efficiency of the hybrid electric drive assembly of the target vehicle based on the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor and the current and voltage of the battery simulator includes:

[0050] Based on the speed and torque of the output end of the test bench input dynamometer motor and the input end of the test bench output dynamometer motor, as well as the current and voltage of the battery simulator, the energy E1 output by the hybrid electric drive assembly to the test bench output end (equivalent to the energy consumed by the vehicle's forward driving wheels), the energy E2 output to the battery simulator (equivalent to the energy recovered by the vehicle's braking and deceleration driving motor in reverse power generation + the energy generated by the generator), the energy E3 output to the test bench input end (equivalent to the energy of the vehicle starting the engine), the energy E4 input by the battery simulator to the hybrid electric drive assembly (equivalent to the forward power supply energy of the vehicle battery), the energy E5 input from the test bench input end to the hybrid electric drive assembly (equivalent to the forward driving energy of the vehicle engine), and the energy E6 input from the test bench output end to the hybrid electric drive assembly (equivalent to the reverse recovery energy of the vehicle's braking and deceleration).

[0051] Then according to the formula Calculate the efficiency of the hybrid electric drive system of the target vehicle.

[0052] The efficiency testing method for a vehicle hybrid electric drive assembly in an embodiment of the present invention comprehensively considers various input energies and output energies, and the efficiency test results are more accurate and reliable.

[0053] As an optional implementation, in one embodiment of the invention, the step of obtaining the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor and the current and voltage of the battery simulator during the bench test further includes:

[0054] Obtain the speed and torque of the generator and drive motor of the hybrid electric drive system during bench testing;

[0055] Analyze the speed and torque of the output end of the test bench input dynamometer in the engine map, analyze the speed and torque of the drive motor in the drive motor map, and analyze the speed and torque of the generator in the generator map.

[0056] Based on the analysis results, the structural parameters and control strategies of the hybrid electric drive assembly of the target vehicle are optimized.

[0057] The embodiment of the present invention performs a map landing point analysis on the data recorded during the bench test, and optimizes the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle based on the analysis results, thereby reducing the energy consumption of the target vehicle.

[0058] As an optional implementation manner, in one embodiment of the invention, the step of analyzing the location of the speed and torque of the output end of the test bench input dynamometer motor in the engine map includes:

[0059] The engine optimization working area is determined based on the relative position of the speed and torque of the output end of the test bench input dynamometer motor in the engine map and the engine optimal line.

[0060] Taking a hybrid electric drive train for a commercial vehicle as an example, after running the CHTC operating conditions on a test bench, the speed and torque of each power source were recorded as shown in Table 1 below. The engine speed and torque are the speed and torque at the output of the test bench's input dynamometer (simulating the engine):

[0061] Table 1

[0062]

[0063] Figure 3 The engine speed and torque landing points at different vehicle speeds are projected onto the engine map. The landing points circled in red are not distributed near the engine optimal line (the deviation from the relative position of the engine optimal line exceeds 10%), and the landing points circled in green are distributed near the engine optimal line (the deviation from the relative position of the engine optimal line does not exceed 10%). The area circled in red can be considered as the engine optimization working area, which can be roughly considered to be a speed of 1400rpm and a torque of less than 150Nm, or a speed of 1400rpm-1600rpm and a torque of less than 200Nm.

[0064] Furthermore, the step of optimizing the structure and control strategy of the hybrid electric drive assembly of the target vehicle according to the analysis results includes:

[0065] When the target vehicle actually operates in the engine optimization operating area, the torque distribution ratio of the engine in the hybrid electric drive assembly is reduced and the torque distribution ratio of the drive motor is increased, or the engine is controlled to stop working.

[0066] pass Figure 3 It can be seen that in the engine optimization working area, the engine efficiency is not high and the fuel consumption is large. Figure 3 When the engine is optimized in the working area, the torque distribution ratio of the engine can be reduced and the torque distribution ratio of the drive motor can be increased, or the engine can be controlled to stop working, which can reduce the energy consumption of the target vehicle.

[0067] As an optional implementation manner, in one embodiment of the invention, the step of analyzing the locations of the speed and torque of the drive motor in the drive motor map includes:

[0068] The optimized working area of ​​the drive motor is determined according to the landing point of the speed and torque of the drive motor in the drive motor map.

[0069] Figure 4 The middle green point represents the speed and torque of the drive motor at a certain drive gear at different vehicle speeds, projected onto the drive motor map. The circled points on the right are not located where the drive motor's efficiency is greater than 95%. Therefore, the circled area on the right can be considered the optimized working area for the drive motor.

[0070] Furthermore, the step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle according to the analysis results includes:

[0071] When the drive motor of the hybrid electric drive assembly of the target vehicle actually operates in the drive motor optimization working area, the output gear position of the drive motor of the hybrid electric drive assembly is adjusted.

[0072] See also Figure 4 and Figure 5 As shown in the figure, when the drive motor of the hybrid electric drive assembly of the target vehicle actually operates in the drive motor optimized working area, the output gear of the drive motor is adjusted so that the landing point originally circled on the right is moved to the position where the drive motor working efficiency is greater than 95%. In a specific application example, Figure 4 There were 1,626 medium-green points, and 287, or 17.7%, achieved an efficiency greater than 95%. Based on the target vehicle's typical speed of 30-70 km / h, by adjusting the drive motor's output gear (generally by increasing the reduction ratio and optimizing the high-speed, low-torque point to a low-speed, high-torque point), the number of points where the drive motor's efficiency exceeded 95% was increased to 33.15%.

[0073] As an optional implementation manner, in one embodiment of the invention, the step of analyzing the locations of the generator speed and torque in the generator map includes:

[0074] The generator's optimized working area is determined based on the generator's speed and torque in the drive motor map.

[0075] Figure 6 The middle green point represents the generator's rotational speed and torque at different vehicle speeds projected onto the generator map. The points circled by black circles are not located where the drive motor's efficiency is greater than 90%. The area circled by black circles can be considered the generator's optimized working area.

[0076] Furthermore, the step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle according to the analysis results includes:

[0077] Adjust the parameters of the planetary gear set between the engine and the generator.

[0078] See also Figure 7 As shown, by adjusting the K value (characteristic parameter of the planetary gear) of the planetary gear between the engine and the generator, the engine speed and torque landing point will change accordingly.

[0079] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0080] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0081] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features of the present invention.

Claims

1. A method for testing the efficiency of a hybrid electric drive assembly of a vehicle, characterized in that: The following steps are involved: Obtaining a preset test condition of a target vehicle, and performing a bench test on a hybrid electric drive assembly of the target vehicle according to the preset test condition; Obtaining the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor during the bench test, as well as the current and voltage of the battery simulator; Calculate the efficiency of the hybrid electric drive assembly of the target vehicle based on the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor, and the current and voltage of the battery simulator; The step of calculating the efficiency of the hybrid electric drive assembly of the target vehicle based on the speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor and the current and voltage of the battery simulator includes: According to the speed and torque of the output end of the test bench input dynamometer motor and the input end of the test bench output dynamometer motor, as well as the current and voltage of the battery simulator, the energy E1 output by the hybrid electric drive assembly to the test bench output end, the energy E2 output to the battery simulator, the energy E3 output to the test bench input end, the energy E4 input from the battery simulator to the hybrid electric drive assembly, the energy E5 input from the test bench input end to the hybrid electric drive assembly, and the energy E6 input from the test bench output end to the hybrid electric drive assembly are calculated; Then according to the formula Calculate the efficiency of the hybrid electric drive system of the target vehicle.

2. The efficiency testing method of a vehicle hybrid electric drive assembly according to claim 1, characterized in that: The step of obtaining the rotational speed and torque of the output end of the bench input dynamometer motor and the input end of the bench output dynamometer motor as well as the current and voltage of the battery simulator during the bench test further includes: Obtain the speed and torque of the generator and drive motor of the hybrid electric drive system during bench testing; Analyze the output speed and torque of the test bench input dynamometer motor in the engine map, analyze the speed and torque of the drive motor in the drive motor map, and analyze the speed and torque of the generator in the generator map. Based on the analysis results, the structural parameters and control strategies of the hybrid electric drive assembly of the target vehicle are optimized.

3. The efficiency testing method of a hybrid electric drive assembly of a vehicle according to claim 2, characterized in that: The step of analyzing the location of the speed and torque of the output end of the test bench input dynamometer motor in the engine map includes: The engine optimization working area is determined based on the relative position of the speed and torque of the output end of the test bench input dynamometer motor in the engine map and the engine optimal line.

4. The method for testing the efficiency of a hybrid electric drive assembly of a vehicle according to claim 3, characterized in that: The step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle according to the analysis results includes: When the engine of the hybrid electric drive assembly of the target vehicle actually operates in the engine optimization operating area, the torque distribution ratio of the engine in the hybrid electric drive assembly is reduced and the torque distribution ratio of the drive motor is increased, or the engine is controlled to stop working.

5. The efficiency testing method of a vehicle hybrid electric drive assembly according to claim 2, characterized in that: The step of analyzing the locations of the speed and torque of the drive motor in the drive motor map includes: The optimized working area of ​​the drive motor is determined according to the landing point of the speed and torque of the drive motor in the drive motor map.

6. The efficiency testing method of a vehicle hybrid electric drive assembly according to claim 5, characterized in that: The step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle according to the analysis results includes: When the drive motor of the hybrid electric drive assembly of the target vehicle actually operates in the drive motor optimization working area, the output gear position of the drive motor of the hybrid electric drive assembly is adjusted.

7. The method for testing the efficiency of a hybrid electric drive assembly of a vehicle according to claim 2, characterized in that: The step of analyzing the locations of the generator speed and torque in the generator map includes: The generator's optimized working area is determined based on the generator's speed and torque in the drive motor map.

8. The method for testing the efficiency of a hybrid electric drive assembly of a vehicle according to claim 7, characterized in that: The step of optimizing the structural parameters and control strategy of the hybrid electric drive assembly of the target vehicle according to the analysis results includes: Adjust the speed ratio between the engine and the generator.

9. The method for testing the efficiency of a hybrid electric drive assembly of a vehicle according to claim 1, wherein: The preset test condition is the CHTC condition.

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