Views:2 Author:Site Editor Publish Time: 2020-02-25 Origin:Site
Developing new standard and upgrading bus safety
In recent years, there have been many big traffic accidents caused by passenger buses in China. These accidents caused heavy losses to people's lives and property, and sounded alarm bells for the safety of passenger bus.
It is understood that China currently has mandatory standards like "Technical Conditions for Motor Vehicle Operation Safety" (GB7258-2016), "Safety Requirements for Structures of Passenger Car " (GB13094-2007), "Comprehensive Performance Requirements and Test Methods for Transport Vehicles" (GB18565-2015) and so on! These mandatory standards stipulate safety technical requirements for operating buses. However, there are problems of decentralization and insufficient system. With the development of the times, the formulation of some indicators is slightly broader today. There is still room for improvement in the overall safety performance of operating buses.
In order to draw lessons from the accident and effectively solve the problem of insufficient safety performance of operating buses, the Ministry of Transport has formulated the JT / T 1094 standard, which puts forward basic safety technical requirements for the safety performance and structural configuration of operating buses. The JT / T 1094 standard is applicable to Class B and Class III operating buses of M2 and M3 (not applicable to school buses), which are various operating buses with a seating capacity of more than 9 people and passengers are not allowed to stand. It means that the standards have influence on all bus manufacturers from large buses to light buses.
The JT / T 1094 standard proposes to improve vehicle safety from seven aspects, including the entire vehicle, steering system, braking system, transmission system, driving system, body structure, strength, exit, and safety protection devices. There are more than 40 clauses in the standard. In addition to direct citing more than 10 existing mandatory standards which are, more than 30 other clauses are new or stricter.
Taking the opportunity to improve the safety of buses to promote the transformation and upgrading of the bus industry, the implementation of the JT / T 1094 standard is of great significance to the bus manufacturing and transportation industries.
Raising requirements and leading international technology level
The reporter learned from the experts who participated in the development of the JT / T 1094 standard that there are some major changes in the JT / T 1094 standard.
As for the entire vehicle, a number of requirements have been added. In addition to the “No floor above the driving zone” so as to cancel one and a half passenger buses, it is also required that gas cylinders should not be arranged on the roof of operating passenger buses, it also limits the height of the luggage compartment. These are to improve the stability of passenger cars and reduce the chance of rollover accidents. In the JT / T 1094 standard, the most technically difficult clause is also in the entire vehicle. In order to reduce the occurrence of rear-end collisions, lane-departure accidents, and injuries caused by accidents, it is required to install an electronic stability control system (ESC) when the vehicle height exceeds 3.7 meters; and passenger cars with a length of more than 9 meters should be equipped with a front collision warning system (FCWS) and Lane Departure Warning System (LDWS).
In terms of braking system, the test method and limits of curve braking stability in the American standard are introduced. It is proposed that for passenger buses with a length of more than 9 meters, all wheels should be equipped with disc brakes. Previous standards only required the installation of front wheels; It has increased installation requirements of brake lining wear automatic alarm device.
Main features of disc brake:
1,Braking efficiency is more stable than drum brake.
2, Good water stability, only small reduce on braking effectiveness after soaking.
3, Smaller size & weight for same braking force output
4, small thermal expansion in the thickness direction of brake disc, good heat dissipation.
Meanwhile, "For operating passenger buses which adopt air braking systems, the working air pressure in brake pipeline should be no less than 1000kpa". These requirements help to improve the efficiency of the braking system, ensuring the stability of braking in corners, and reduce abnormal operation of the braking system caused by driver's poor awareness of maintenance.
Innovative ways to give passengers more life security
The provisions of the JT / T 1094 standard related to the transmission system propose that in order to prevent accidents caused by the transmission shaft falling off during driving, it is required to install protective devices to prevent the drive shaft connection device from falling off and causing danger. In terms of driving systems, in order to reduce accidents caused by runaway tire bursts of operating passenger buses, operating passenger buses cars should be equipped with tubeless radial tires, tire pressure monitoring systems or tire pressure alarm devices. In particular, the standard requires that "the front wheels of passenger buses with a length of more than 9 meters should be fitted with emergency tire safety devices that meet the requirements". This rule expands the scope of mandatory installation of tire emergency safety devices.
Major changes also have been made in body structure, strength, and exits, with the goal of quickly evacuating and escaping for passengers after accident. The standard requires that at least two extrapolated emergency windows should be provided on the left and right sides and emergency doors should be provided on the left side of the body for operating buses longer than 9 meters in length. And there should be at least one extrapolated emergency window on each side for those operating buses from 7 meters to 9 meters in length.
In addition, the JT / T 1094 standard has made innovations in the Exit of bodywork. The standard requires that emergency exits should be provided at the rear wall of operating buses, but the rear windshield of large operating buses is blocked by the seat headrests, and most of them cannot meet the size equirements for the design of emergency windows, which are effective channels for a quick evacuation and escape after a rollover accident. In response to this, the standard proposes that "the headrests of the last row of passenger seats shall be designed to be quick-reversing, quick-removing or other methods to meet requirements for passing emergency windows." In the past, there was no special provision for the emergency exits for passenger bus. The purpose of presenting this special requirement is to increase the space for assengers to escape in emergency situations and increase the possibility of escape.
In terms of safety protection devices, it is proposed that the flame retardant performance of the interior materials of operating buses should meet the new requirements; the volume of the fuel tank is restricted, and only a single structure can be used. Fuel tank side protection devices should be installed for passenger bus which fuel tank sides are not protected by the body stringers. These requirements are to reduce the chance of getting fire after an accident.