Snow removal vehicle low temperature cold start
R&D introduction
The track snow removal vehicle is developed according to the scientific and technological research and development plan of the former Ministry of Railways: Deep Research on Railway Disaster Prevention and Mitigation Technology - Special Equipment and Technology Research Requirements for Snow Removal on Railway Lines. The special snow removal equipment for clearing work can also be used as a tractor in non-snow removal conditions.
Working conditions and power
The rail snow removal vehicle is a special snow removal equipment for high-speed railways, and the ambient temperature of snow removal operation conditions is generally between -35 and -0. As a protection type snow removal operation, the snow removal operation time is generally between 1:00 a.m. and 6:00 a.m. When not in operation, the single machine leaves the operation section at high speed and stops at the station line or special line to stand by; when it is used as an emergency snow removal operation, the operation time According to the on-site situation, when the operation is required, a single machine generally enters the operation area from the docking place to carry out snow removal operations.
According to the operating characteristics and operational safety and reliability requirements of the rail snow removal vehicle, the configuration of the power system must meet at least the following three requirements: The rail snow removal vehicle must have a dual power system to ensure that any power system fails during the self-running process of the single machine. Another set of power systems can ensure that the track snow removal vehicle leaves the working section at high speed by itself. The power system of the rail snow removal vehicle must have good low temperature cold start performance, especially if the external AC power supply cannot be provided, it can also start smoothly under the low temperature condition of -35. The power system of the rail snow removal vehicle needs to provide continuous power when the main engine is turned off to meet the operator's needs for warmth, maintenance, and lighting. The power system of the rail snow removal vehicle mainly includes: 2 diesel engines with a rated power of 500kW, a diesel generator set with a rated power of 30kVA, and related components to meet the requirements of installation and startup.
Initiate action plan
2.1 The main factors affecting the low temperature start-up performance of the power system of the rail snow removal vehicle
The minimum temperature requirement for the operating environment of the rail snow removal vehicle is -35. The diesel engine and generator set in the non-operating state are generally in a shutdown state and the shutdown time cannot be determined. Docked at the station line and the backup line, there is no guarantee that an external power supply can be provided before starting. Based on the above conditions, the main factors affecting the low temperature cold start performance of the rail snow removal vehicle include the following aspects: the suction temperature and the ambient temperature in the cylinder are too low (may reach -35), resulting in a drop in the temperature at the end of compression, poor ignition performance, and stagnation of ignition The long period of time leads to poor cold start performance; with the decrease of ambient temperature, the viscosity of the engine lubricating oil increases, the fluidity becomes poor, the rotation resistance of the crankshaft is increased, and the starting performance of the engine is reduced. As the ambient temperature drops, the capacity and terminal voltage of the starting battery will decrease, which will inevitably lead to a decrease in the starting torque of the engine, which directly affects the starting performance of the engine. Since the output end of the engine is connected to the transfer case and the hydraulic pump, as the ambient temperature decreases, the viscosity of the hydraulic oil increases, and the starting resistance of the drive pump increases, resulting in an increase in the starting resistance of the engine and a decrease in the starting performance of the engine.
2.2 Measures to improve the low temperature starting performance of the power system
The measures to improve the low temperature cold start performance of the power system mainly include the following aspects: diesel, antifreeze and diesel oil must be selected to meet the needs of low temperature environment. When the ambient temperature is lower than -30, diesel should be -50 diesel and antifreeze should be FD -2 type long-acting antifreeze, diesel oil use SAE0W/40 type CG or above grade lubricating oil. The engine is equipped with a low temperature cold start system. This system can automatically preheat the intake air according to the change of the external temperature. During the preheating process, the preheating is always on. After the preheating is completed, the preheating light goes out, and the engine can be started. The system can ensure that the engine starts smoothly when the ambient temperature is higher than -32. The diesel generator set adopts an AC/DC water jacket water heating system. When the outside world can provide 220V AC power, the antifreeze liquid of the diesel generator set is heated by the external power supply. When the temperature of the antifreeze liquid is higher than the heating indication signal, the diesel generator set is started. . When the outside world cannot provide 220V AC power supply, the antifreeze of the diesel generator set is heated by the built-in battery of the snow plow (starting battery configured for the two engines) through the inverter, and the diesel generator set is started after the heating indicator light sends a signal. . Once the diesel generator set starts with
