Founded in 1998, the State Key Laboratory of Vehicular Transmission is the ONLY national research laboratory in the vehicle transmission field in China. The representative ones out of the 220 large-scale equipments in the lab include: (1) Dynamic performance simulation test platform, (2) Steering performance test platform for power shift steering transmission, (3) Environmental simulation test platform, (4) Electro-mechanical transmission test platform, (5) Reduction of vibration and noise test platform, (6) Lubrication and sealing test platform of the friction units in transmission, (7) Virtual assembly test platform and modern design center, etc. Additionally, there is also a designate test platform for full condition testing of tracked vehicles, which is capable of testing the steering characteristics of 1400 KW as the largest power shift steering transmission used in tracked vehicle. It should be noted that the environmental simulation test platform can generate all-weather conditions with different temperature, humidity and vibration to simulate various working circumstances for vehicle transmission systems.
Some of the typical equipments are highlighted as follows:
1) Full Operating Condition Test Platform for Power Shift Steering Transmission of Tracked Vehicles (PSSTT)
This test platform for PSSTT is the world large power equipment (1400 KW in maximum) to test the full operation condition of the power shift steering transmission in tracked vehicles, as shown in Fig. 3.3. This testing platform consists of the generator-motor driving and loading system, gearbox, testing system and the DSPACE real-time simulation control system. In particular, the electrically enclosed steering system for the transmission of tracked vehicle has been approved as a national invention patent.
The driving and loading system can be operated in two control modes – constant speed control and constant torque control. It runs with the rated speed 2400 r/min, the rated torque 6366 N·m and the rated power 1000 KW. The specification details of this systems are as follows:
① Control accuracy of speed up to ±1 r/min;
② Control accuracy of torque up to 0.5%;
③ Response time to the rated torque less than 40 ms;
④ Fastest response to the rated speed without load 0.8 s.
This system also has several functional characteristics: running in four quadrants, full loading at zero speed, eliminating its own inertia, simulating the load conditional of real road and engine performance and electrically enclosed circulation, etc. At full loading, the energy saving can reach to 90%, which is very energy efficient. The test platform completely meets the requirements of testing the circulating power in steering system, high power energy saving and high dynamic loading of the transmission in tracked vehicles.
2) Environmental Adaptability Test Platform (EATP) for Transmission Components
The EATP is a comprehensive environmental adaptability test system considering simultaneously three environmental factors such as temperature, humidity and vibration, constructed according to high-level international standards. With generator driving and electricity dynamometer loading, this system enables researchers to created all-weather conditions to simulate complex working circumstances for tested vehicles. This system employs computer remote control and direct on-site control strategy for data monitoring, acquisition, processing and real-time control. It is also equipped with other auxiliary parts such as sensors, connections, fuel supply unit, cooling and power supply system, etc. The main units of this system include: 615 KW diesel engine, power shift steering transmission, current dynamometer, environmental chambers, gearbox, speed torque sensor, universal shaft, and vibration platform, etc.
The environmental chamber for temperature and humidity testing (Fig. 3.4) is used for environmental adaptability from low to high temperature and humidity test. The basic specifications of this system are as follows:
① Temperature range: -55℃~150℃;
② Temperature fluctuation: ≤ ±0.5℃;
③ Temperature average change rate: ≥10℃/min;
④ Humidity range: 10%-98%;
⑤ Internal effective volume: 12 m3.
The vibration platform as shown in Fig. 3.5 is mainly used for vibration/shock test, environment stress test, and reliability test. The main technical parameters are as follows:
① Rated sinusoidal thrust 196 KN;
② Frequency range 5-2200 HZ;
③ Maximum acceleration 980 m/ s2(100g);
④ Maximum speed 180 cm/s;
⑤ Maximum displacement 51 mm;
⑥ Rated load 2000 kg;
⑦ Size of platform φ600 mm;
⑧ Equivalent mass of moving parts 130 kg;
⑨ Rated output power 200 kVA.
The main function of the anechoic chamber as shown in Fig. 3.6 is to provide the acoustic testing environment to investigate the vibration and noise performance during the component or full-size vehicle development. The anechoic chamber meets the standard by ISO 3745 and GB 6882, which is validated by the measurement by National Metrology Institute.
The background noise is 14 dB, and the lower cut-off frequency is 63 Hz. The 180 degree distribution of sound field is very suitable to simulate the free field environment. The absorber of semi-anechoic chamber employs the sound absorption splinter made by the metal armored plate. The size of the chamber after the installation of the splinter is 15.8 m×12.6 m×8.7 m, with the radius of free field no less than 5 m. The floor of the anechoic chamber is integrally suspended on an elastic foundation, allowing the isolation rate as much as 99%. The temperature of anechoic chamber is controlled by the outdoor air conditioning units, with the cooling, heating, dehumidification, ventilation functions. The maximum heat dissipated power is up to 750 kW. The fresh air ventilation system is specially designed to meet the demands of engine testing, and the indoor ventilation rate can be up to 8-10 time per hour.
