Status Of TPMS Standards And Regulations in Countries （3）

The United States is the first country in the world to formulate and enforce TPMS regulations. The National Highway Traffic Safety Administration (NTHTSA) had developed FMVSS 138 regulations, requiring that after September 2007, all four-wheel passenger cars and commercial vehicles with a maximum design total mass of 4536kg sold in the United States must have a tire pressure monitor system. Driven by US federal legislation and market opportunities, major automotive electronics companies had invested a great deal of enthusiasm in research and development. At the same time, many well-known chip manufacturing companies had joined in, continuously introducing new generation products which were smaller, lighter, more reliable, and longer-lived. At present, TPMS equipment in the United States has been exceedingly pervasive.

 

Standards of Different Countries

    The International Organization for Standardization (ISO) formulated the international standard ISO 21750: 2006 for tire pressure monitor systems in March 2006. The American Society of Automotive Engineers also developed the SAE J 2657 standard for tire pressure monitor systems for light vehicles in December 2004. At present, the above-mentioned contents are all referable international automobile regulations and standard projects.

 

In addition, Japan Automotive Standards Organization (JASO) had also developed a technical document for the TPMS real vehicle test method, whose technical content was basically a refinement of the US FMVSS 138 regulations. The Brake and Walking Mechanism Working Group (GRRF) under the "World Vehicle Technical Regulations Coordination Forum (UN / WP29)", which was responsible for formulating European and global automotive technical regulations, decided to establish a the TPMS informal working group, with Germany as the presidency to promote the formulation of the regulation, and held informal working group meetings in November 2007, February and September 2008 to discuss the feasibility of formulating ECE regulations related to TPMS. Conversely, judging from the content of several meetings, this work was much more difficult than expected, and consequently, the progress kept not fast.

 

Advantages and Disadvantages of Various Standards

(1) The US Federal Regulation FMVSS 138 is a mandatory safety standard, and which only specifies the most basic functional requirements in terms of performance requirements. When the tire air pressure is lower than the specified air pressure value, the TPMS should issue an under-pressure visual alarm signal within 20 minutes. FMVSS 138 regulations not only stipulate the relevant requirements of visual alarm signals, but also stipulate the test conditions, test procedures and detailed implementation transition period. Due to the restriction of the technical level at the time when the US regulations were formulated, only the most basic undervoltage alarm function was specified, and the indirect TPMS was taken into account. However, due to the defects of the indirect TPMS, the product has a multitude of problem. It cannot be monitored when the vehicle is stationary. Determine whether the period of low air pressure is too long (about 20min). The system is prone to false alarms. Under certain special conditions, the system cannot monitor low air pressure and cannot display air pressure. Thus, it can be seen that all products that meet this regulation are not necessarily safe and reliable products. Furthermore, in the specific application process, users complained about frequent false alarms of some products.

 

(2) SAE J 2657: 2004 standard specifies the test method and performance requirements of the TPMS installed in tubeless tires. It mainly stipulates specific test methods for each performance of the tire pressure monitoring sensor module, and on top of that, the standard gives specific requirements on the performance of the alarm signal display method, system working conditions, and the most basic performance. The standard stipulates that the system should monitor the tire pressure from 24km / h to the maximum speed. On the contrary, it has no requirements on the service life of the product with measurement accuracy, and the response time of the undervoltage alarm is also long (within 10min), which is basically similar to FMVSS 138 in function.

 

(3) The ISO 21750: 2006 standard applies to the tire pressure monitor system used for tubeless tires, which requires monitoring of all tires used and provides information to the driver. The standard specifies comprehensive performance requirements for the system and components, which also specifies that the system should monitor tire pressure after the vehicle speed exceeds 25km / h.

 

The above three standards impose requirements on TPMS from different aspects. However, for an electronic product that requires extremely high safety and reliability, these standards and regulations are still lacking in requirements. For example, how to reflect and ensure the reliability and stability of the system signal transmission, how to reflect and ensure that the system can reach a service life of more than 6 years, how to avoid false alarms and missed alarms, these are the difficulties in TPMS design and formulation of standards Key technology. If you are interested at replacing tire sensor and progammable tpms such as toyota tire pressure sensor, bmw tyre pressure sensor, ford tire pressure sensor and so on, welcome to contact us.