Free-standing, portable EMI/ EMC chassis dynamometer

 

The free-standing, portable EMI/ EMC chassis dynamometer generally consists of an anechoic chamber or reverberation chamber, measuring instruments, and a hub dynamometer system that simulates the road load of the vehicle. The rotating hub dynamometer system that simulates the vehicle load can be designed as a two-wheel drive, four-wheel drive or more shaft drive dynamometer according to the number of drive shafts of the vehicle. The free-standing, portable EMI/ EMC chassis dynamometer can also adopt a structural type embedded in the turntable or as a mobile type.

 

Free-standing, portable EMI/ EMC chassis dynamometer

 

Embedded EMC chassis dynamometer system

 

The embedded EMC chassis dynamometer system generally consists of a drum unit and a dynamometer unit that simulate loads before and after. The pitch of the drum unit is adjustable. Embedded dynamometers are generally embedded in the turntable and can rotate with the turntable, or embedded in the raised floor. Before the test, the moving axis unit of the dynamometer is adjusted to the required distance according to the wheelbase of the vehicle. The interface inputs the vehicle into the hub, locks the vehicle front and rear through the ratchet strap, and connects the exhaust pipe to start the test. The dynamometer system has the following characteristics:

 

  • Each dynamometer unit is an independent unit for modular assembly.
  • Each dynamometer unit can carry out independent torque or speed control to simulate road load.
  • It can be used for vehicle test in anechoic chamber or reverberation chamber.
  • It can be customized according to user needs.
  • The spacing of the multi-axis dynamometer is adjustable to adapt to vehicle testing with different wheelbases.
  • It can be equipped with autonomous driving robot, exhaust emission system, vehicle windward system, etc.
  • The unique shielding technology can meet the Class 5 requirements of CISPR25.
  • The dynamometer has high torque and speed control accuracy and high repeatability.
  • The dynamometer can be embedded in the turntable or under the raised floor.
  • The vehicle fixing device is integrated with the dynamometer body, which is firm and reliable.
  • With vehicle tire burst detection device.
  • With vehicle centering detection device.

 

Embedded EMI/ EMC chassis dynamometer

 

Recommended dynamometer parameters:

TypePrated (kW)Frated (N) (b) /axleVmax (km/h)Vrated (rpm)F2 (N)@ Vmax /axle
EMC-E1-X (a)22260010060790
EMC-E2-X345016100601216
EMC-E3-X748716100602658
  • X — indicate the number of axles of the dynamometer (e.g. four-wheel drive vehicle, generally use 2-axis drive dynamometer)
  • Frated — indicate the traction of single drive shaft of the dynamometer. The overall traction force of the dynamometer system is the number of active axles of the dynamometer multiplied by the traction force of single axle

 

 

Portable EMC chassis dynamometer system

 

The portable EMC chassis dynamometer adopts a modular structure. The bottom is designed with heavy-duty load-bearing universal wheels, which can be pushed into the anechoic chamber. The adjustable bracket is placed in the supporting position. The vehicle is driven through the approach bridge into the test position. The power cables, communication optical fibers and pneumatic pipelines are connected. The vehicle is driven onto the chassis dynamometer and the vehicle is fixed with a ratchet strap to start the test.

Portable EMI/ EMC chassis dynamometer

TypePrated (kW)Frated (N) (b) /axleVmax (km/h)Vrated (rpm)F2 (N)@ Vmax /axle
EMC-M1-X (a)22260010060790
EMC-M2-X345016100601216
  • X — indicate the number of axles of the dynamometer (e.g. four-wheel drive vehicle, generally use 2-axis drive dynamometer)
  • Frated — indicate the traction of single drive shaft of the dynamometer. The overall traction force of the dynamometer system is the number of active axles of the dynamometer multiplied by the traction force of single axle




Detailed technical description of portable, free-standing EMC chassis dynamometer

 

System structure

 

The free-standing, portable EMI/ EMC chassis dynamometer is generally composed of an electric wave anechoic chamber, a rotating hub dynamometer system and measuring instruments. We generally provide anechoic chamber and dynamometer system. The dynamometer system needs to be determined according to the parameters of the product to be tested. The dynamometer system generally includes: load simulation drum unit, vehicle cooling system, wheelbase adjustment system, automatic driving robot, vehicle tyre device, exhaust emission system, real-time control system and other parts.

 

Key technical indicators

 

  1. System parameters

     

    Drum configuration2 x (Ø240mm ~ Ø320mm)
    Dynamometer2 units/ axis
    Dynamometer rated power22kW ~ 75kW/ unit
    Base speed100 km/h
    Acceleration or deceleration1g (10km/h ~ 60km/h)

    0.5g (10km/h ~ 100km/h)

    Axle load2t/ axis
    Wheelbase adjustment accuracy±1mm
    Wheelbase adjustment range1800mm ~ 3200mm (customizable)
    Adapt to the track1200mm ~ 2100mm (customizable)
    Adapt to tire diameter400mm ~ 800mm
    Allowable environment0 ~ +60°C

 

  1. Description of parameter accuracy

     

    Steady-state load control accuracy± 0.5%FS
    Load control repeatability± 0.2%FS
    Speed control accuracy± 0.1km/h
    Distance measurement accuracy0.1m/km
    System response timeChanging the system when the driving force of the drum surface reaches 90% of the given value, the response time does not exceed 100ms
    Traction1 N
    Speed0.02 km/h
    Test distance0.01 m
    Slide interval time0.01 s
    Time resolution1ms

 

  1. EMC performance parameters

     

    Electromagnetic radiation

    • 15dB lower comparing with the limits of CISPR 12 and CISPR 25.
    • Frequency range: 30MHz ~ 1GHz
    • Measuring distance: 10m

     

    Electric field radiation

    • 15dB lower comparing with the limits of SAE J551-5:2004-01 and GB/T 18387-2008.
    • Frequency range: 9KHz ~ 30MHz
    • Measuring distance: 3m

     

    Magnetic field radiation

    • 10dB lower comparing with the limits of SAE J551-5:2004-01 and GB/T 18387-2008.
    • Frequency range: 9KHz ~ 30MHz
    • Measuring distance: 3m




Key technology description of portable, free-standing EMC chassis dynamometer

 

  1. Road load simulation dynamometer

     

    The dynamometer adopts induction asynchronous motor and is controlled by a four-quadrant inverter. It can realize the speed and torque control of the dynamometer. Each set of dynamometer and frequency converter are integrated in a unit body for complete shielding. The cable between the inverter and the dynamometer is extremely short, which greatly reduces electromagnetic radiation. The controller and each inverter communicate through optical fiber to realize dynamic control of the dynamometer and feedback of measurement parameters.


    Road load simulation dynamometer

 

  1. Rotary hub

     

    The hub is in direct contact with the vehicle tire. The surface has a certain degree of roughness, which is used to simulate road friction. The EMI chassis dynamometer adopts a small double rotary hub structure to facilitate the positioning of the vehicle. The surface of the hub is sprayed with hard chromium alloy, which is wear-resistant and oil-resistant, and can simulate the friction of the road surface. The drum is a fabricated structure and the stress is relieved before precision machining. Both ends of the drum assembly are supported by heavy-duty grease lubricated spherical roller bearings which are dynamically balanced after assembly. The parameters of the drum are described in the following table:

     

    Drum diameter240 mm
    Drum width900 mm
    Drum pitch900 mm
    Drum materialCarbon steel
    Surface coatingMetal spraying
    Spray thickness200 um
    Coefficient of frictionBetter than 0.8
    Surface roughness300±50 um
    Surface hardnessBetter than 135 B
    Concentricity0.25 mm
    Maximum runout0.25 mm
    Balance levelG2.5
    Maximum axle load2000 kg

     

    Rotary hub of EMI/ EMC chassis dynamometer

 

  1. Wheelbase adjustment system

     

    For the embedded EMC chassis dynamometer, a servo motor is used to drive the reducer and screw to push the dynamometer unit to move back and forth. The portable EMC dynamometer unit body is installed on the sliding guide rail, and the rolling circulation chain plate structure is adopted, which can easily realize the front and back movement of the dynamometer unit body. The wheelbase of the dynamometer can be manually controlled, or the movement distance can be input, and the target position can be automatically positioned. The position control accuracy is ±1mm.

     

    Wheelbase adjustment system of EMI/ EMC chassis dynamometer

    The portable EMC chassis dynamometer does not require a forward and backward movement mechanism. The front and rear axle dynamometers are independent modules that can be moved manually to adjust the distance and adapt to the wheelbase of the vehicle.

 

  1. Rotary hub brake system

     

    When the vehicle enters the chassis dynamometer, the hub brake system brakes the hub to facilitate the vehicle to enter the test position. The hub brake system uses a pneumatic brake. When the brake system is turned on, the brake brakes the hub. When the brake system is turned off, the brake is automatically released. The system has the brake position detection function. When the brake is not reset, the test system cannot be started, and the user is prompted to reset the hub brake system.

 

  1. Vehicle fixtures

     

    The vehicle fixing device adopts a high-strength heat-resistant ratchet strap. One end is connected to the hook on the chassis dynamometer steel frame, and the other end is connected to the hook on the front and rear ends of the vehicle. The ratchet mechanism facilitates the fastening of the vehicle. Each ratchet strap can withstand 10t tension.

 

  1. Flat tire detection device

     

    When the vehicle is tested, if the tire bursts suddenly, the tire burst detection device will be triggered. The system stops immediately and immediately triggers the vehicle to stop.

     

    Flat tire detection device of EMI/ EMC chassis dynamometer

 

  1. Vehicle displacement detection device

     

    During the test of the vehicle, if the fixing device is loose or the vehicle hook is disconnected, the test vehicle will rush out of the test area and cause serious losses. Once the axial position of the vehicle moves, the displacement detection device will be triggered. The system immediately stops the dynamometer and triggers the vehicle to stop.

 

  1. Windward system

     

    When the vehicle is tested in anechoic chamber, the vehicle position is fixed and an upwind cooling system is required. The test system is equipped with two windward systems, which are mobile and embedded. The mobile type adopts a mobile fan and guides the cooling wind to the front end of the vehicle through a wind guide device. The embedded windward system embeds the fan into the dynamometer. It is installed under the raised floor of the anechoic chamber. Through the wind guide device, the cooling wind is guided to the front end of the vehicle.

 

  1. Exhaust emission system

     

    For fuel vehicles or hybrid vehicles, an exhaust emission device is provided. The system adopts high temperature resistant bellows and quick connection device which can be quickly connected with the exhaust pipe of the vehicle to discharge the exhaust gas into the exhaust gas treatment pipeline of the anechoic chamber.


    Exhaust emission system of EMI/ EMC chassis dynamometer

 

  1. Autonomous driving robot

     

    The automatic driving robot adopts a pneumatic actuator, which realizes the control of the vehicle accelerator by manually controlling the stroke of the pneumatic actuator in the control room. The pneumatic actuator can be controlled manually after automatic to realize the control of the vehicle brake pedal.

    • Throttle lever displacement: 0 ~ 100 mm
    • Throttle lever operating force: 200 N
    • Brake lever displacement: 0 ~ 125 mm
    • Brake lever operating force: 350 N
    • Power supply: 220 VAC
    • Compressed air: 0.6 bar


    Autonomous driving robot of EMI/ EMC chassis dynamometer

 

  1. Real-time control system

     

    The real-time control system adopts a quad-core embedded microprocessor and the fastest and stable EtherCAT communication method. The control program of the dynamometer is written into the real-time controller which can realize real-time dynamic control without disturbance. The host computer is only used as data display, processing, saving, triggering command sending and other functions.

    The real-time control system can independently control each wheel hub dynamometer, as well as master-slave control. It can also simulate road loads such as ramp resistance.





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