New technologies and new applications allow sensors to penetrate every corner of the car

Today's cars are not just a means of transportation, they also shoulder the significance of improving the quality of life. In addition to saving fuel and electricity, today's cars need to be safer, more comfortable and more user-friendly, all of which rely on the application of excellent sensors. Because of this, people pay more and more attention to sensor technology, and the development speed of the market is also astonishing.

Strategy Analytics predicts that from 2004 to 2009, the global automotive sensor market will show a growth rate of about 9%, and the market demand in 2008 is estimated to reach 1.487 billion. The Chinese market is a hotbed for the development of automotive sensors. According to the latest survey data from CCW Research, the market sales of automotive sensors in China reached US$390 million in 2006, a year-on-year growth rate of 42.8%. The annual compound growth rate of sales of automotive sensors in China will exceed 35% from 2007 to 2010. It is estimated that the market sales will reach 540 million US dollars in 2007, with a year-on-year growth rate of 36.3%; the market sales will be close to 1.05 billion US dollars in 2009, with a year-on-year growth rate of 40.5%; and the market sales will exceed 1.32 billion US dollars in 2010, with a year-on-year growth rate of 35.2%.

Automotive electronics There are many types of sensors involved. We will analyze the development of the most representative sensor technology in the Chinese market for you, and provide some inspiration for your related design work. Safety performance is the main focus, and innovative applications continue to emerge With the gradual popularization of automobiles, people's requirements for automobile safety and comfort performance have become higher and higher. Many countries have even formulated relevant standards to standardize this. Christopher Cook, general manager of the automotive, industrial and diversified electronics market department of Infineon Technologies North America, said: "The American automotive industry requires automobiles to use tire pressure monitoring systems (TPMS) to meet relevant safety regulations. Our goal is to develop increasingly intelligent sensors to make car driving safer, further reduce fuel consumption and pollution emissions, and play an increasingly important role in engine management." In other regions, especially Europe, TPMS is also becoming increasingly popular. People's attention to automobile safety is obvious. In order to help customers improve the competitiveness of automobile products, various sensor manufacturers are particularly attentive to technological development. In addition to continuing to follow the path of intelligence, integration and miniaturization, innovative sensor application models are also emerging. At the end of last year, Infineon launched the SP35 tire pressure sensor at the Convergence 2006 exhibition. This is the first device that integrates all the functions of the TPMS module into a single package. This highly integrated device is mounted on a printed circuit board (PCB) and forms a complete TPMS module together with the battery and antenna, allowing automotive industry suppliers to cost-effectively meet the requirements of US safety regulations. The independent package device integrates microelectromechanical system (MEMS) pressure, acceleration and temperature sensors with an 8-bit microcontroller. The TPMS module and the electronic control unit communicate wirelessly through amplitude/frequency modulation (AM/FM), radio frequency (RF) transmitters and low frequency (LF) receivers. The MCU chip also has memory, battery voltage monitors and advanced power control units. By removing the independent communication chip in the TPMS module, the SP35 reduces the complexity and cost of module design by about 10%. Echoing Infineon's SP35 single-chip TPMS solution, Freescale's 8-pin tire pressure monitoring sensor MPXY8020A is also a highly integrated product. It consists of a variable capacitance pressure sensor element, a temperature sensor element and an interface circuit (with wake-up function), all three of which are in a single chip (as shown in Figure 1). The MPXY8020A can be used in conjunction with a remote keyless entry (RKE) system to provide a highly integrated, low-cost system.

Figure 1: Freescale tire pressure monitoring sensor MPXY8020A structural diagram

MEMS is a bright spot in sensor technology for automotive safety applications. Experts have recently proposed the concept of a car "black box" to monitor the speed of the car, the use of seat belts, and the super-gravity caused by sharp turns, sudden braking, unstable driving, abnormal deceleration, and unsafe reversing, and provide guidance and warning assistance to the driver. These systems are equipped with accelerometers and gyro sensors, and use MEMS technology to reduce device size and cost, and have been recognized by the market. John P. Pyle, North American Sales Director of Memsic, said: "The market for 'black boxes' will spread all over the world. We expect that all car manufacturers will install some form of black box in the future. This will inevitably lead to a sharp increase in the market share of MEMS sensors and accelerometers. We expect that by 2007, the sales scale of MEMS sensors in the automotive field will reach 1.5 billion US dollars, including all MEMS sensors and accelerometers, of which accelerometers account for 70%."

In high-end cars, people often use smart image sensors to assist driving. Due to the high price of the sensor, it has not been popularized. However, recently, Swiss company CSEM announced that its real-time vision system designed with ViSe intelligent image sensor can reduce the cost of automotive vision system from thousands of dollars to hundreds of dollars. CSEM adopts a dual-chip solution, that is, the company's proprietary vision sensor is matched with ADI's inexpensive Blackfin DSP. CSEM is planning to integrate a proprietary DSP chip with its image chip to provide a single-chip solution.

Sensor technology for reversing system applications is also one of the hot topics at present. Murata has launched a series of ultrasonic sensor products for reversing systems. Taking its MA40MF14-5B as an example, this product not only has the characteristics of small size, waterproof, narrow range detection, short ringing time, etc., but the most special feature is that this product uses an asymmetric grating of 110°×50° to improve the accuracy of detection and avoid misoperation. As shown in Figure 2.

Figure 2: MA40MF14-5B grating orientation diagram

Start with precision and optimize Engine and chassis control technology As the core technology of automobiles, the requirements of engine control systems and chassis control systems for sensors have always been high precision and high reliability. This type of sensor technology is already very mature, and its market is mainly in North America and Europe. In this application field, in order to further enhance the added value of automobiles, sensor manufacturers have made a lot of efforts in precision, such as using advanced sensors to improve the efficiency of battery use. Take the battery IVT sensor recently launched by Delphi as an example. As more and more on-board electronic devices increase the workload of batteries and AC motors that provide power to them, the importance of accurately calculating the battery state of charge (SOC) to ensure the best performance of the battery is becoming increasingly prominent. Delphi's battery IVT sensor can help batteries achieve optimal performance. After using the IVT sensor, the car can run 0.5 miles more per gallon of fuel. The battery IVT sensor can accurately measure the current (I), voltage (V) and temperature (T), which are the three key parameters for determining the working state of the battery. "Delphi's battery IVT sensor reduces the amount of power the alternator needs to deliver when the battery is fully charged, which reduces mechanical load on the engine and improves fuel efficiency," said Dave Wright, global director of innovation and electronic/electrical systems at Delphi.

Figure 3: Illustration of sensor applications in automobiles

At present, there are not many manufacturers in China that produce automobile engine and chassis control systems, so there are very few sensors for such applications in the Chinese market. However, the market for body control and infotainment systems is very large, and a large number of technologically mature products have emerged in the market. How to apply these excellent products in an innovative way is the primary issue facing automobile manufacturers and is also the key issue in determining the "grade" of automobiles.