Modification Scheme of Railway Diesel Generator Set

At present, the common electric equipment on the railway uses Liangmei generator sets, one is the German MTU diesel generator (including MTU12V183 and MTU8V396 models) as the prime mover, called MTU generator set; the other is The Huachai Deutz diesel generator as the prime mover is called Huachai Deutz generator set. Because Huachai Deutz diesel is relatively good in performance and price, it can be said to be of high quality and low price, and the performance of the diesel generator is stable. Therefore, it has become the mainstream model of various road bureaus. However, since this model is not specially designed for generator sets, with the deepening of application, some unreasonable aspects of design and installation have gradually been exposed, and we will talk about our views and improvement measures in combination with the application situation of the railway department.

 Cooling System

Original structure

In order to reduce vibration in the cooling system, the connection pipe between the large circulation water inlet of the machine’s water pump and the radiator is connected by a hose and a hoop.

Common faults in the application.

In practical application, because these two places are in the middle area of vibration reduction and slowing down, the relative movement is large: the temperature of the cooling water changes greatly, such as the water temperature can change from 5C to 90C in winter; this place is located at the lowest point of the cooling water system, and the water pressure is large; plus The anti-corrosion liquid and DCA protective agent added to the cooling water increase the water penetration ability: in addition, the joints at the original joints are too short, so after a period of use, the water pipes often age and become rotten, resulting in joints Leakage, or even water inlet falling off (usually occurs when the water pressure is too high), resulting in waste of resources and failure of the machine, and even affect the punctual operation of the train in serious cases, such as the Hangzhou depot in the summer of 1999 because of the water supply of No. 3 machine Excessive water pressure caused the support knot to fall off and the train was powered off for 10 minutes.

Suggestions for improvement

Considering the high temperature resistance, anti-aging, anti-corrosion and vibration reduction of the parts at this position, and considering that the water pressure in the water system is not very high, we make the water pump large circulation inlet and temperature-saving outlet into flanges The connection soft camp adopts metal bellows, and rubber gaskets are properly added to the connection.

Exhaust System

Original Structure

In the exhaust system of Deutz diesel generators, in order to discharge the exhaust gas outside the vehicle, the current generator set adopts a parallel arrangement, and a 90° right-angle elbow, bellows, muffler and The silent speaker is discharged directly out of the car.

Deficiency analysis

In the diesel generator exhaust system of the generator set, the exhaust elbow, bellows, muffler, and chimney are located on a vertical line. Such a structure is unreasonable:

• There are mute boxes (shutters), but due to some reasons in the application, the mute boxes are often not closed tightly, and the rain falls, causing the exhaust gas turbine blades and turbine shells to rust, thereby destroying the dynamic balance of the turbine and damaging the turbine.
• Due to the vertical arrangement, when the exhaust passage, especially the muffler, is rusted, there is no hiding place for the debris that falls off when the machine vibrates, so it enters the volute directly through the 90 elbow, thereby mechanically destroying the exhaust gas turbine. This phenomenon was during the relocation of the diesel generator in our school. When the elbow was disassembled, I found rust and some metal fragments at the volute mouth.

Suggestions for improvement

According to the actual situation of the generator set, it is impossible to change the arrangement of the exhaust method, so it is suggested to change the structure of the exhaust 90°, add a dust collection pit at the bottom, and install a valve, so that the place can be cleaned regularly, which can significantly reduce Supercharger failure rate.

Lubrication System

original structure

The oil pan is used as the oil removal device of the engine oil. Due to the Cummins diesel generator B-level maintenance regulations, the engine oil must be replaced every 250 hours or half a year or when the oil quality enters the case. Come drain the oil. Due to the working characteristics of the generator set and the long working hours, the oil needs to be drained basically every half a month, that is, the oil drain plug needs to be screwed in every half a month.

Frequently asked questions

As far as the current structure is concerned, the feedback from the site has the following shortcomings: First, because the oil pan is thin and made of aluminum alloy, the wear resistance is poor, frequent twisting will cause thread failure, and oil leakage needs to be reprocessed when the oil leakage is serious. Second, the oil seal needs to be replaced every time the oil is changed to ensure the seal, which increases material loss. Third, because the space under the oil pan on the vehicle is narrow, it is not conducive to the recovery of waste oil. Generally, it can only be discharged through the bottom of the vehicle. In addition, due to the oil discharge When the oil temperature is high (generally around 80°C), it is difficult for the flight attendants to retrieve the bolts, the magnetic block is often lost, and the oil chassis is more oily and difficult to clean.

Improvement measures

Refit the oil drain plug, use the corresponding thread of the o25 camp head car, and add a valve to the pipe to replace the original oil drain plug. In terms of valve selection, it is easy to use a snorkel valve instead of a ball valve. It is stuck by iron filings. In order to avoid the lack of magnetic adsorption iron after using the oil drain valve, a ring magnet can be installed on the oil drain pipe between the oil bottom and the gate valve, which is beneficial to absorb the iron in the oil and reduce wear. Easy to operate, not easy to damage, and easy to recycle waste oil.