Transmission and reducer test bench
The increasing electrification of contemporary drivetrains is significantly impacting the demands placed on instrumentation and testing systems. As the automotive industry shifts towards electrified drivetrains, engineers face new challenges in ensuring that all components work seamlessly together. This shift necessitates early driveline testing to validate the performance and compatibility of various propulsion system components, including the EV reducer, hybrid engine, plug-in hybrid electric vehicle (PHEV) transmission, and traditional ICE.
To effectively manage these parallel development efforts, early-stage testing of the driveline systems is crucial. This proactive approach allows engineers to identify potential issues before they escalate, ensuring that the final product meets performance, efficiency, and safety standards. The reducer test bench plays a vital role in this process. Specifically designed to oversee the verification of any unit under test (UUT) during the development phase, the reducer test bench provides a controlled environment where various performance metrics can be assessed.
The reducer test bench is equipped with advanced instrumentation that allows for precise measurements of torque, speed, and efficiency. By simulating real-world operating conditions, it enables engineers to evaluate how the EV reducer performs under various loads and speeds. This thorough testing process is essential for optimizing the design and functionality of the reducer, which is a critical component in electric drivetrains. Additionally, the reducer test bench supports the testing of transmissions.
DynoEquip has developed a comprehensive range of test rigs specifically designed for passenger cars, light-duty and heavy-duty trucks, buses, tractors, and off-road vehicles. These test rigs are engineered to meet the diverse testing needs of various vehicle types, ensuring thorough evaluation under a wide range of conditions.
One key feature of these test rigs is their ability to accommodate scenarios where an appropriate drive unit is substituted for the original propulsion unit. This flexibility allows engineers to conduct comparative testing of different propulsion systems, including traditional ICEs, hybrid systems, and fully electric drive devices.
DynoEquip’s test rigs offer various testing methods, including noise, vibration, and harshness (NVH) testing, which is essential for ensuring passenger comfort. Additionally, they evaluate overall performance metrics such as acceleration, fuel efficiency, and top speed, helping manufacturers fine-tune their vehicles for optimal performance.
Functionality testing verifies that all vehicle systems operate as intended under various conditions, ensuring safety and reliability. Durability testing subjects vehicles to rigorous conditions to simulate long-term usage, identifying potential failure points and enhancing component longevity.
Key applications of transmission and reducer test bench
- Assessment of the spinning components and UUT case’s stipulated strain limits
- Assessment of the stipulated life of the bearings and gear teeth
- Estimating brake and clutch pack lifetimes
- Analyzing and improving component dimensioning
- Coordinating strategy and performance
- Potential to switch to portable-based testing
Light-duty electric vehicle reducer test bench for performance tests
The drive machine must fit precisely within the designated installation space while also meeting the required speed and torque specifications for the replacement e-motor. This is crucial for ensuring optimal performance and compatibility with the existing drivetrain. The reducer test bench is designed to accommodate varying axle configurations, whether in an offset or coaxial setup. This flexibility is essential for testing a wide range of applications, as different vehicles may require different configurations based on their design and purpose.
In addition to accommodating various axle configurations, the reducer test bench incorporates sophisticated mechanical solutions that effectively connect the load machine to the unit under test (UUT). These connections are crucial for accurately simulating real-world operating conditions and ensuring that the UUT can be tested under the specific loads and dynamics it will encounter in actual use.
The design of the drive machine allows for direct mounting to the input shaft, particularly in a transverse layshaft axle arrangement. This is made possible by the drive machine’s compact diameter and high-speed capability, which can reach up to 20,000 rpm. This high-speed range is particularly advantageous for applications requiring rapid acceleration and precise performance metrics, enabling engineers to conduct detailed performance evaluations efficiently.
Target test piece
- The reducer in the drivetrain systems for battery-electric or hybrid city cars, SUVs, and Sports cars.
- The transmission in the driveline module of purely electric as well as hybrid light commercial vehicles weighing up to 7.5 tons.
Typical applications of test stand
- Durability of reducer
- Evaluation of performance
- Assessment of efficiency
Small-diameter PM drive machine
| Model | Rated power (kW) | Rated torque (Nm) | Max. speed (rpm) | Inertia (kgm2) |
| PMI1 | 500 | 1,000 | 8,000 | 0.12 |
| PMI2 | 388 | 530 | 20,000 | 0.06 |
** Parameters can be changed according to customer needs
Asynchronous machine
| Model | Rated power (kW) | Rated torque (Nm) | Max. speed (rpm) | Inertia (kgm2) |
| ATT1 | 400 | 5,000 | 4,500 | 4.4 |
| ATT2 | 350 | 4,200 | 4,000 | 3.5 |
| ATT3 | 300 | 3,700 | 3,500 | 2.4 |
** Parameters can be changed according to customer needs
Permanent magnetic synchronous load machine
| Model | Rated power (kW) | Rated torque (Nm) | Max. speed (rpm) | Inertia (kgm2) |
| PTT1 | 300 | 4,000 | 3,000 | 0.85 |
| PTT2 | 250 | 3,000 | 3,000 | 0.62 |
** Parameters can be changed according to customer needs
Heavy-duty transmission test bench for performance tests
The drive machine is designed to efficiently reach the required speed and torque specifications, eliminating the need to consider the installation dimensions of the load machine. This flexibility is particularly beneficial in space-limited environments. Typically, two, four, or more load machines are utilized, capable of generating impressive torque outputs of up to 20,000 Nm. This capability is essential for accurately simulating the demanding conditions faced by modern vehicles, particularly in high-performance applications.
For units under test (UUT) with exceptionally high torque requirements, matched gearboxes may be necessary. These gearboxes optimize the transmission of power from the drive machine to the UUT, ensuring effective torque delivery while maintaining the desired speed. This integration allows for precise adjustments to accommodate varying specifications.
Additionally, the transmission test bench facilitates heavy-duty axle testing, which is crucial for manufacturers of trucks and industrial machinery. By enabling extensive testing of components under significant load conditions, the test bench helps ensure durability and reliability in real-world applications.
Target test piece
The plug-in hybrid transmission connected to the e-motor in the battery electric vehicles such as:
- Medium-duty commercial vehicles, from 7.5 tons up to 26 tons, for regional goods distribution and inner-city delivery.
- Heavy-duty commercial vehicles for long-haul transportation above 26 tons.
- Buses and coaches
- Off-highway and large-engine sectors such as mining machinery, off-road vehicles, tractors and combine harvesters, municipal vehicles, mobile machinery, and construction vehicles such as excavators and loaders.
Typical applications of test rig
- Durability of transmission
- Durability of axle
- Evaluation of performance
- Assessment of Efficiency
The typical project of EV reducer test bench
To meet the design verification needs of electric vehicle (EV) drivetrain projects during the development stage, the testbed equipped with a climatic chamber plays a crucial role. This specialized setup is essential for thoroughly testing various aspects of the EV drivetrain, including vehicle control strategy development, control unit parameter matching, and calibration. By simulating real-world conditions, the testbed allows engineers to refine the interactions between transmission, and other components to ensure optimal performance and efficiency. The climatic chamber further enhances this process by enabling tests under extreme environmental conditions, such as high and low temperatures and varying humidity levels, ensuring that the drivetrain can reliably operate in diverse climates.
In addition to control strategy and parameter testing, the testbed facilitates comprehensive evaluations of the drivetrain’s dynamics, economy, environmental reliability, and durability. Engineers can simulate different driving scenarios to assess how the vehicle behaves during acceleration, braking, and cornering. This dynamic testing is crucial for understanding vehicle stability and handling. Moreover, the testbed evaluates energy efficiency by measuring energy consumption under various operating conditions, helping to optimize the drivetrain for improved range and reduced operational costs. Rigorous durability testing subjects the components to prolonged use and stress, allowing engineers to identify potential failure points and enhance the overall reliability of the EV drivetrain.
Applications of EV reducer test bench
The use of this rig includes, but is not limited to, the following forms and contents of electric vehicle driveline testing:
- Control strategy development, control parameter matching, and calibration work of the controller
- Driveline efficiency test
- Electric vehicle energy consumption test
- Temperature rise and heat balance test
- Standard working conditions (NEDC, FTP, JC08, WLTP, etc.) test
- Customized working conditions (full-throttle acceleration, rapid acceleration, and deceleration, brake energy recovery, coasting customized curve, etc.) simulation test
- Maximum speed, 30-minute maximum speed, acceleration capacity (V1 to V2), hill climbing speed simulation test
- Actual whole vehicle road spectrum playback test
- Stall simulation test
- Comprehensive endurance and high-speed endurance test
- E-motor and controller test
- Oil pump and controller test
- Fatigue endurance test of axle teeth
- Damp heat cycle endurance test
- High-temperature and low-temperature calibration test
System major configurations
Frequency converter system
Pulse width modulation (PWM) inverter provides upper-level control of speed and torque for one drive machine and two load machines. The inverter power converter has a four-quadrant control function, and the system surplus power can be fed back to the grid.
Drive machine system
The drive machine has high dynamic response characteristics. The test stand takes into account single e-motor testing, drivetrain testing, and electric vehicle reducer testing. For testing, the drive machine is directly connected.
Load machine system
The load machine system is mainly used for road resistance loading and wheel speed simulation.
Battery simulator
The battery simulator is used to provide different voltages and currents to the e-motor controller in the sample system. By setting the model parameters (internal resistance, capacitance, capacity, temperature, efficiency, etc.), the battery pack output characteristics simulation software can simulate the voltage and current output of a specific vehicle power battery pack.
Sensor data measurement and acquisition system
Sensor front-end I/O panel and data aggregator are installed in the rocker box on the floor or wall of the testbed. The acquisition function of the digital acquisition module can be configured through software to meet the different needs of users.
Oil temperature control device
This device is removable and the cooling and heating power is continuously adjustable. This device is used to control the e-motor oil temperature to a preset value.
Coolant temperature control device
This unit is removable, the cooling and heating power is continuously adjustable, and the unit is used to control the e-motor, controller, DC/DC converter, and battery coolant temperature and flow to preset values.
Climatic chamber
This bench is required to be equipped with an environmental chamber, which is used to simulate the environmental temperature and humidity of the tested parts, such as the differential reducer driveline.
Console
The console is used for placing or installing computers, CAN communication boxes, low-voltage DC power supplies, emergency power supplies, emergency stop switches, safety controllers, and so on.
Rig automated control system
The rig automation control system contains the necessary software and hardware, which can complete various performance and durability tests and calibrations of electric vehicle drivetrain.
Vehicle driving and road condition simulation software
The software has complete simulation functions for driver, vehicle, speed, road condition, road load, and brake energy recovery, to realize dynamic simulation of driving behavior and vehicle response on the bench. The control model parameters and PID parameters of the above modules can be set and adjusted by users to meet the testing requirements of different UUTs.
UUT mounting and connecting fixtures
The bracket is used to mount the drivertrain to the base plate.
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