By Zhang Lipeng in Beijing | CRRC | Updated: 14-Sep-2018
On September 18, CRRC launched its new generation carbon fiber metro vehicle “CETROVO” at the Innotrans 2018 in Berlin.
CETROVO, in which the advanced new materials and technologies meet and melt, is fully upgraded compared with traditional ones in terms of energy efficiency, environmental protection, comfort and intelligence.
A 13% decrease in total weight facilitated by carbon fiber technology.
Compared with traditional metros, the most important feature of the new generation metro vehicle is more light-weighted and energy efficient.
Lightweight is a concept about building metro vehicles that are less heavy as a main way to achieve better energy efficiency. As a new material, carbon fiber composite is known as the best lightweight material and has several advantages including high strength and low weight, standing out an excellent solution for producing lightweight trains.
According to Ding Sansan, a scientist of CRRC and deputy chief engineer of CRRC Sifang, the new generation metro vehicle incorporates advanced carbon fiber technology: the carbody, the bogie frame, the driver’s cab, the equipment cabinet and the equipment body are all made of carbon fiber composite materials. This means that it is a metro vehicle with large-scale application of carbon fiber composite materials for the first time in China. In particular, key technical difficulties in structural design and molding of large complicated parts made of carbon fiber are solved, and this realizes the full application of carbon fiber composite materials in the main bearing structures such as carbody, bogie frame and driver's cab.
The weight of the vehicle is amazingly reduced by virtue of carbon fibers. Compared with traditional metal materials such as steel and aluminum alloy, the new generation carbon fiber composite metro vehicle is much lighter. To be specific, there is a more than 30% decrease in the weight of carbody, driver’s cab and equipment cabinet respectively, a 40% decrease in bogie frame and a 13% decrease in the complete vehicle.
“Although the manufacturing cost of carbon fiber composite material is higher than traditional metal material, the former is much lighter and has obvious strength in energy-saving, and it also has some excellent performances in fatigue resistance, tolerance to different weather conditions and corrosion resistance, which can effectively ensure the metro vehicle free from failures due to fatigue and corrosion in its 30-year of service life, thus the maintenance work is reduced and the entire life cycle cost is decreased,” Ding Sansan said, a lighter vehicle also reduces damage to the metro line.
In addition to carbon fiber lightweight technology, the new generation metro vehicle is provided with a new energy-efficient traction system to achieve better energy efficiency. By upgrading the asynchronous motors employed by traditional metro vehicles to the direct drive technology of the permanent magnet synchronous motors and adopting silicon carbide converter device, the traction efficiency of the vehicle is greatly improved.
It is estimated that the new generation metro vehicle can comprehensively save more than 15% of energy.
Flexible composition of metro vehicles
The new generation metro vehicle is more applicable. It is much more flexible in terms of operation organization and can adapt to more complex operating conditions.
The new generation metro vehicle features flexible composition. Two coupled cars are regarded as the minimum composition unit, and based on this, the metro vehicle is applicable for a flexible “2+N”-car composition depending on the traffic needs. This means that the metro train can consist of 2 to 12 cars, and it takes less than 5 minutes to change the number of cars in operation for the train.
Passenger flow for metro operation varies greatly in a day: morning and evening peak hours see large passenger flow while the mid-day handles a relatively small number of passengers. The flexible composition enables the new metro train to use more cars for peak hours and fewer cars for small passenger flow, and this is beneficial to cost-effective operation, energy efficiency, operation cost reduction and service improvement by shortening departure interval.
The new generation metro vehicle is tolerant to tougher conditions, which means that it can run smoothly in complex environmental conditions such as high temperature, high humidity, low temperature (-40℃) and high altitude (2500 m).
Given the fact that the metro lines feature many curves and small radius, the vehicle is innovatively provided with active radial system on bogie that can control the wheelset to roll on the radial position of the curve when the metro vehicle is detected to approach a curve section. This greatly improves the performance of the vehicle to negotiate a curve, especially the small-radius curves, and the minimum turning radius can be 80 meters; wheel wear is also substantially reduced, saving maintenance costs.
The vehicle can also run without external power supply. Power battery as the energy storage system can provide traction power for the vehicle to travel for 15 km. This facilitates emergency operation in case of power failure as well as vehicle operation in the neutral sections along the route and in depots.
High running stability, more riding comfort
The new generation metro vehicle incorporates advanced vibration and noise reduction technology to make the journey more comfortable.
When a metro vehicle is running, it will vibrate due to track irregularity, and the vibration should be reduced through the suspension system on the bogie. The traditional metro vehicle is equipped with nonadjustable suspension system that is called passive suspension.
The new metro vehicle is designed of a full-active suspension system for the first time: vibration of the vehicle during operation can be immediately detected and damping of the suspension system will be subject to dynamic adjustment. In this sense, the suspension system can always suppress vibration to the best, realizing high riding quality.
It is also quieter inside the vehicle. As the noise reduction design is optimized, the noise level in the passenger compartment is only 68 dB when the vehicle is running, lower than the traditional one by more than 3 dB.
According to what Ding Sansan said, like high-speed trains, the new generation metro vehicle is also adopted airtightness design and utilizes a sealed carbody. Passengers will not feel more pressure acting on their eardrums due to pressure fluctuations in the compartment.
An “Intelligent Train”: watching videos on window
Benefiting from the modern intelligent technology, the new generation metro vehicle is also an “intelligent train”.
Intelligent services can be found in each detail of the vehicle. The passenger compartment is just like a touchscreen computer. To be specific, the car window acts as a super Pad to provide various graphics, texts and videos. Passengers can watch news, browse the Web, buy tickets, watch videos and live TV shows on the window. All these services are easily accessed by passenger’s finger touch on the window. Mirrors in the compartment also support touch technology and are provided with Internet access. Air conditioners in the compartment can automatically choose the appropriate temperature and humidity according to the actual weather and dressing index, making passengers feel more comfortable. The lighting system keeps track of the light environment of the compartment and automatically adjusts the brightness and color temperature. In addition, multimedia curved screen, self-cleaning seat and hearing aid system for hearing-impaired passengers are also provided. All these intelligent services will bring a new travelling experience to passengers.
For the new generation metro vehicle, the maximum operation speed is 140 km/h. The vehicle is adopted the driverless technology, which means that the metro vehicle is under fully automatic control on the whole journey, including vehicle starting, acceleration, deceleration, stopping, door opening and closing, and returning to the station.
Maintenance for operation is also more intelligent. For the vehicle, a powerful intelligent sensing system is established, where more than 1,100 monitoring points are set to sense the status of the train in real time. Automatic warning and remote maintenance are available in case of abnormal operation conditions. Meanwhile, with the help of the intelligent sensing system, the vehicle can be promptly arranged for maintenance when it is in subhealth status, and the line condition can also be detected and properly maintained, making the metro vehicles run safer and more reliable.
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