German mainland company develops tire pressure monitor that can calculate air pressure based on tread pattern deformation

Continental has developed a tire pressure monitor that uses a sensor on the inside of the tire tread, and plans to begin installing it on a tire that is leased to a transport company with a large number of trucks in 2011. In 2012, it started to produce passenger cars. Although currently in negotiations, it is planned to start with one or two models. Following the US stipulation of TPMS deployment obligations, the EU in 2012 and South Korea in 2013 will also become obligations, and Japan is also making relevant considerations. Given this situation, mainland companies plan to prepare for the spread of TPMS.

The sensor uses a MEMS (Micro Electro Mechanical Systems) sensor that measures radial acceleration. When the coordinate axis is fixed to the axle, the sensor will trace a substantially perfectly circular path when it is not in contact with the road surface, and will trace a substantially linear path when the sensor contacts the road surface due to deformation of the tread pattern and close contact with the road surface. At this time, the joint between the perfect circle and the straight line will cause acceleration due to the sensors “landing” and “moving from the ground”. As this process advances, the sensor will experience peak output. In this way, the length of the linear motion, that is, the length of the grounding, can be calculated based on the peak-to-peak time interval and the rotation speed. Through the length of the ground, the degree of deformation of the tire can be known, thereby obtaining the tire pressure value.

Prices have not yet been decided, but mainland companies say they are definitely cheaper than existing products. The model installed on the valve detects the pressure itself, so the accuracy of the sensor is directly related to the accuracy of the monitor. However, this detection method does not require high precision for the sensor itself. The reason for this is that the accuracy is determined by the time interval of the peak, and it is only necessary to detect "the occurrence of the peak value".

The MEMS sensor combined with the acceleration sensor and temperature sensor is integrated with the processing circuit in a single chip. The components of the sensor are only three parts: the tire pressure monitor chip, the battery, and the antenna that transmits the measurement results to the vehicle. In terms of weight, the existing sensor installed on the tire valve was originally a 37g, and the improved version currently being developed also has 26 to 27g of the product, while the model attached to the tire is only 11g. Models installed on tire valves have a battery life of 10 years, and the new sensor can reach the same 6 years as a tire.

Attach a cylindrical container inside the tire tread and place the sensor inside. It is also considered to fix together with the vulcanization process in the mass production. Although the mainland company is also a tire manufacturer, it does not intend to use the TPMS exclusively for self-produced tires. Instead, it will actively supply competitive tire manufacturers.