A test method for the efficiency of a DHT hybrid powertrain

Abstract

A DHT hybrid powertrain efficiency test method belongs to the performance test of hybrid powertrain. The overall efficiency measurement of the DHT hybrid powertrain in various working modes can be achieved. The following steps are included: S1. The DHT is installed on the powertrain test bench, and the DHT hybrid powertrain is installed; S2. Simulate the first working condition, put the DHT into the P gear, control the DHT hybrid powertrain to work in the standby power generation mode, and calculate the oil-to-electricity conversion efficiency of the DHT hybrid powertrain in the standby power generation mode; S3. Simulate the second working condition, put the DHT into the D gear, control the DHT hybrid powertrain to work in the EV mode, and calculate the efficiency of the DHT hybrid powertrain in the EV mode; S4. Simulate the third working condition, put the DHT into the D gear, control the DHT hybrid powertrain to work in the PS mode, and calculate the efficiency of the DHT hybrid powertrain in the PS mode; S5. Simulate the fourth working condition, put the DHT into the D gear, control the DHT hybrid powertrain to work in the EVCT mode, and calculate the efficiency of the DHT hybrid powertrain in the ECVT mode.

Description

Technical Field

[0001] The invention relates to a performance test of a hybrid powertrain, and in particular to a test method for performing a DHT hybrid powertrain efficiency test on a powertrain bench. Background Art

[0002] As fuel consumption regulations become increasingly stringent, hybrid products are becoming more and more popular. The overall efficiency of the powertrain is an important indicator of the fuel consumption rate of the entire vehicle. The overall efficiency of the hybrid powertrain needs to be measured during the development phase to provide support for product optimization. The efficiency of conventional powertrain products is generally tested separately for the universal characteristics of the engine and the transmission efficiency of each gear of the transmission. However, for hybrid powertrain products, since one or more motors are added to participate in the work, the energy source is not only the chemical energy of gasoline combustion but also the electrical energy stored in the vehicle battery. The original test method cannot meet the measurement and evaluation needs.

[0003] The current efficiency test of DHT hybrid powertrain is limited to the efficiency test of each component of DHT hybrid powertrain, including engine, motor, etc., and it is impossible to measure the overall efficiency of the whole powertrain. When calibrating the fuel economy of DHT hybrid powertrain, it is necessary to refer to the overall efficiency of each working mode, which helps to optimize the control strategy and reduce the fuel consumption rate. It is often necessary to constantly adjust the switching strategy of each mode and select the optimal strategy through a large number of real vehicle fuel consumption tests.

[0004] Therefore, providing a method for measuring the overall efficiency of a DHT hybrid powertrain is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] In order to meet the overall efficiency test requirements of DHT hybrid powertrain products, the present invention provides a test method for performing DHT hybrid powertrain efficiency test on a powertrain test bench, which can achieve overall efficiency measurement of the DHT hybrid powertrain in various working modes.

[0006] The technical solution adopted by the present invention is:

[0007] A DHT hybrid powertrain efficiency test method comprises the following steps:

[0008] S1. The DUT is installed on the powertrain test bench. The DUT is a DHT hybrid powertrain.

[0009] S2. Simulating working condition 1, putting the DHT into P gear, controlling the DHT hybrid powertrain to work in the standby power generation mode, and calculating the oil-to-electricity conversion efficiency of the DHT hybrid powertrain in the standby power generation mode;

[0010] S3. Simulating working condition 2, putting the DHT into D gear, controlling the DHT hybrid powertrain to operate in EV mode, and calculating the efficiency of the DHT hybrid powertrain in EV mode;

[0011] S4. Simulating working condition 3, putting the DHT into D gear, controlling the DHT hybrid powertrain to work in PS mode, and calculating the efficiency of the DHT hybrid powertrain in PS mode;

[0012] S5. Simulate working condition 4, put the DHT into D gear, control the DHT hybrid powertrain to work in ECVT mode, and calculate the efficiency of the DHT hybrid powertrain in ECVT mode.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention can directly measure the overall efficiency of the DHT hybrid powertrain under different working modes. The test can be completed on a test bench using the powertrain. The optimal working range of each mode can be determined in advance without waiting for the actual vehicle test stage, which greatly shortens the optimization verification time of the control strategy and improves the development progress of new product projects. DETAILED DESCRIPTION

[0015] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0016] A DHT hybrid powertrain efficiency test method comprises the following steps:

[0017] S1. The test device used in the test method of the present invention is a powertrain test bench, and the tested part is a DHT hybrid powertrain (engine + DHT hybrid-specific transmission). When conducting the test, the tested powertrain is installed on the powertrain test bench, and the intake and exhaust system, half-axle, and suspension of the powertrain all use real vehicle parts. The dynamometer of the test bench simulates the wheels of the real vehicle absorbing the power generated by the powertrain, and the battery simulator simulates the battery of the real vehicle to provide power to the powertrain and absorb the power generated by the powertrain. The mounting angle of the DHT hybrid powertrain is consistent with that of the real vehicle.

[0018] S2. Simulating working condition 1, putting the DHT into P gear, controlling the DHT hybrid powertrain to work in the standby power generation mode, and calculating the oil-to-electricity conversion efficiency of the DHT hybrid powertrain in the standby power generation mode;

[0019] Specifically: S21. put the DHT into P gear, and control the DHT hybrid powertrain to work in the standby power generation mode;

[0020] S22. By controlling the speed of the DHT generator, the engine speed is ensured to be 1000, 1500, ..., 4000rpm (in steps of 500rpm to the maximum speed at which the engine can operate);

[0021] S23. Control the engine torque to 25, 50, ..., 250 Nm (with a gradient of 25 Nm to the maximum torque at which the engine can operate);

[0022] The engine torque is controlled by the engine management system EMS (or ECU); the test bench control system sends the target torque to the engine management system EMS, and the EMS controls the engine torque.

[0023] S24. After this operating condition stabilizes, measure the instantaneous fuel consumption of the engine and the power generation of the DHT generator.

[0024] S25. Calculate the conversion efficiency of the assembly in standby power generation mode according to the following formula:

[0025] Fuel consumption power (kW) = 3600 × engine instantaneous fuel consumption (kg / h) × fuel calorific value (kJ / kg)

[0026]

[0027] Among them: calorific value is a characteristic of fuel and is only related to the type of fuel. Therefore, the calorific value of gasoline is a specific value and can be provided by the oil supplier.

[0028] S3. Simulating working condition 2, putting the DHT into D gear, controlling the DHT hybrid powertrain to operate in EV mode, and calculating the efficiency of the DHT hybrid powertrain in EV mode;

[0029] Specifically: S31. put the DHT into the D gear, and control the DHT hybrid powertrain to work in the EV mode, in which the engine speed is always 0;

[0030] S32. By controlling the dynamometer speed, the speed of the DHT drive motor is ensured to be 1000, 2000, ..., 12000rpm (with a gradient of 1000rpm to the maximum speed at which the drive motor can operate);

[0031] S33. Control the DHT drive motor torque to 25, 50, ..., 250Nm (with a gradient of 25Nm to the maximum torque at which the drive motor can operate);

[0032] The DHT drive motor torque is controlled by the drive motor control system MCU; the test bench control system sends the target torque to the drive motor control system MCU, and the MCU controls the drive motor torque.

[0033] S34. After the working condition is stabilized, the power consumption of the DHT drive motor, the speed and torque of the left half-axle dynamometer, and the speed and torque of the right half-axle dynamometer are measured respectively;

[0034] S35. Considering that the electric energy consumed by the powertrain comes from the engine driving the generator to generate electricity, the equivalent fuel consumption power is calculated using the highest oil-to-electricity conversion efficiency measured in the standby power generation mode, and then the assembly efficiency is calculated. The efficiency of the EV mode assembly is calculated according to the following formula:

[0035]

[0036] Total input power (kW) = motor equivalent fuel consumption power (kW)

[0037]

[0038] S4. Simulating working condition 3, putting the DHT into D gear, controlling the DHT hybrid powertrain to work in PS mode, and calculating the efficiency of the DHT hybrid powertrain in PS mode;

[0039] Specifically: S41. put the DHT into the D gear, and control the DHT hybrid powertrain to work in the PS mode;

[0040] S42. The engine speed is ensured to be 1000, 1500, ..., 3000 rpm (in steps of 500 rpm to the maximum operating speed of the engine) by controlling the dynamometer speed;

[0041] S43. Control the engine torque to 25, 50, ..., 250Nm (with a gradient of 25Nm to the maximum torque that the engine can operate);

[0042] The engine torque is controlled by the engine management system EMS (or ECU); the test bench control system sends the target torque to the engine management system EMS, and the EMS controls the engine torque.

[0043] S44. Control the DHT drive motor torque to 25, 50, ..., 250 Nm (with a gradient of 25 Nm to the maximum torque at which the drive motor can operate);

[0044] The DHT drive motor torque is controlled by the drive motor control system MCU; the test bench control system sends the target torque to the drive motor control system MCU, and the MCU controls the drive motor torque.

[0045] S45. After the working condition is stabilized, measure the instantaneous fuel consumption of the engine, the power consumption of the DHT drive motor, the speed and torque of the left half-axle dynamometer, and the speed and torque of the right half-axle dynamometer respectively;

[0046] S46. Considering that the electric energy consumed by the powertrain comes from the engine driving the generator to generate electricity, the equivalent fuel consumption power is calculated using the highest oil-to-electricity conversion efficiency measured in the standby power generation mode, and then the assembly efficiency is calculated. The efficiency of the PS mode assembly is calculated according to the following formula:

[0047]

[0048] Engine working fuel consumption power (kW) = 3600 × engine instantaneous fuel consumption (kg / h) × fuel calorific value (KJ / kg)

[0049]

[0050] Total input power (kW) = engine working fuel consumption power (kW) + motor working equivalent fuel consumption power (kW)

[0051]

[0052] S5. Simulate working condition 4, put the DHT into D gear, control the DHT hybrid powertrain to work in ECVT mode, and calculate the efficiency of the DHT hybrid powertrain in ECVT mode.

[0053] Specifically: S51. put the DHT into the D gear, and control the DHT hybrid powertrain to work in the ECVT mode;

[0054] S52. By controlling the dynamometer speed, the speed of the DHT drive motor is ensured to be 1000, 2000, ..., 12000rpm (with a gradient of 1000rpm to the maximum speed at which the drive motor can operate);

[0055] S53. By controlling the speed of the DHT generator, the engine speed is ensured to be 1000, 1500, ..., 4000rpm (in steps of 500rpm to the maximum speed at which the engine can operate);

[0056] S54. Control the engine torque to 25, 50, ..., 250 Nm (with a gradient of 25 Nm to the maximum torque at which the engine can operate);

[0057] The engine torque is controlled by the engine management system EMS (or ECU); the test bench control system sends the target torque to the engine management system EMS, and the EMS controls the engine torque.

[0058] S55. Ensure the total power generation is 1, 2, 3, 4, 5 kW by controlling the torque of the DHT drive motor;

[0059] The DHT drive motor torque is controlled by the drive motor control system MCU; the test bench control system sends the target torque to the drive motor control system MCU, and the MCU controls the drive motor torque.

[0060] S56. After the working condition is stabilized, measure the instantaneous fuel consumption of the engine, the power generation of the DHT powertrain, the speed and torque of the left half-axle dynamometer, and the speed and torque of the right half-axle dynamometer respectively;

[0061] S57. Calculate the efficiency of the ECVT mode assembly according to the following formula:

[0062]

[0063] Total output power (kW) = mechanical output power (kW) + DHT power generation power (kW)

[0064] Engine working fuel consumption power (kW) = 3600 × engine instantaneous fuel consumption (kg / h) × fuel calorific value (kJ / kg)

[0065] Total input power (kW) = engine fuel consumption power (kW)

[0066]

[0067] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A DHT hybrid powertrain efficiency test method, characterized by: The following steps are involved: S1. The DUT is installed on the powertrain test bench. The DUT is a DHT hybrid powertrain. S2. Simulating working condition 1, putting the DHT into P gear, controlling the DHT hybrid powertrain to work in the standby power generation mode, and calculating the oil-to-electricity conversion efficiency of the DHT hybrid powertrain in the standby power generation mode; S3. Simulating working condition 2, putting the DHT into D gear, controlling the DHT hybrid powertrain to operate in EV mode, and calculating the efficiency of the DHT hybrid powertrain in EV mode; S4. Simulating working condition 3, putting the DHT into D gear, controlling the DHT hybrid powertrain to work in PS mode, and calculating the efficiency of the DHT hybrid powertrain in PS mode; S5. Simulate working condition 4, put the DHT into D gear, control the DHT hybrid powertrain to work in ECVT mode, and calculate the efficiency of the DHT hybrid powertrain in ECVT mode. The S3 is implemented by the following steps: S31. Put the DHT into the D gear, and control the DHT hybrid powertrain to work in the EV mode; S32. By controlling the dynamometer speed to ensure that the speed of the DHT drive motor is 1000rpm as a gradient, to the maximum speed at which the drive motor can operate; S33. Control the DHT drive motor torque with a gradient of 25Nm to the maximum torque that the drive motor can operate; S34. After the working condition is stabilized, the power consumption of the DHT drive motor, the speed and torque of the left half-axle dynamometer, and the speed and torque of the right half-axle dynamometer are measured respectively; S35. Calculate the equivalent fuel consumption power using the highest oil-to-electricity conversion efficiency measured in the standby power generation mode in step S2, and then calculate the overall efficiency.

2. A DHT hybrid powertrain efficiency test method according to claim 1, characterized in that: The S2 is implemented by the following steps: S21. Put the DHT into P gear to control the DHT hybrid powertrain to work in standby power generation mode; S22. By controlling the speed of the DHT generator, the engine speed is ensured to be in a gradient of 500 rpm to the maximum speed at which the engine can operate; S23. Control the engine torque in a gradient of 25 Nm to the maximum torque at which the engine can operate; S24. After the working condition is stabilized, the instantaneous fuel consumption of the engine and the power generation of the DHT generator are measured respectively; S25. Calculate the oil-to-electricity conversion efficiency of the DHT hybrid powertrain in the standby power generation mode.

3. A DHT hybrid powertrain efficiency test method according to claim 2, characterized in that: The oil-to-electricity conversion efficiency calculation formula in S25 is: 。 4. A DHT hybrid powertrain efficiency test method according to claim 1, characterized in that: The calculation formula of the EV mode assembly efficiency in S35 is: 。 5. A DHT hybrid powertrain efficiency test method according to claim 3, characterized in that: The S4 is implemented by the following steps: S41. Put the DHT into the D gear, and control the DHT hybrid powertrain to work in the PS mode; S42. By controlling the dynamometer speed to ensure that the engine is at a gradient of 500rpm to the maximum speed at which the engine can operate; S43 controls the engine torque to a gradient of 25Nm to the maximum torque at which the engine can operate; S44 controls the DHT drive motor torque to a gradient of 25Nm to the maximum torque at which the drive motor can operate; S45. After the working condition is stabilized, measure the instantaneous fuel consumption of the engine, the power consumption of the DHT drive motor, the speed and torque of the left half-axle dynamometer, and the speed and torque of the right half-axle dynamometer respectively; S46. Calculate the equivalent fuel consumption power using the highest oil-to-electricity conversion efficiency measured in the standby power generation mode in step S2, and then calculate the overall efficiency.

6. A DHT hybrid powertrain efficiency test method according to claim 5, characterized in that: The calculation formula of the PS mode assembly efficiency in the S46 is: 。 7. A DHT hybrid powertrain efficiency test method according to claim 6, characterized in that: The S5 is implemented by the following steps: S51. Put the DHT into the D gear, and control the DHT hybrid powertrain to work in the ECVT mode; S52. By controlling the dynamometer speed, the DHT drive motor is ensured to be at a gradient of 1000 rpm to the maximum speed at which the drive motor can operate; S53. By controlling the speed of the DHT generator to ensure that the engine speed is in a gradient of 500rpm to the maximum speed at which the engine can operate; S54. Control the engine torque in a gradient of 25 Nm to the maximum torque at which the engine can operate; S55. Ensure the total power generation is 1, 2, 3, 4, 5 kW by controlling the torque of the DHT drive motor; S56. After the working condition is stabilized, measure the instantaneous fuel consumption of the engine, the power generation of the DHT powertrain, the speed and torque of the left half-axle dynamometer, and the speed and torque of the right half-axle dynamometer respectively; S57. Calculate the efficiency of the ECVT mode assembly.

8. A DHT hybrid powertrain efficiency test method according to claim 7, characterized in that: The calculation formula of the ECVT mode assembly efficiency in S57 is: 。

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