The sensor generally used in the vehicle is a driving computer system as an input device, which converts various working condition information in the running of the vehicle, including: vehicle speed, vehicle condition, temperature of various media, engine working condition and road information, etc. into The signal is transmitted to the computer so that the engine is in the best working condition, the exhaust pollution is the minimum, and the stability control of the vehicle makes the driving the safest. It is a key component of the automotive electronic control system and the main research core of the automotive electronics technology.
1. The main factor in the development of automotive sensors - safety and comfort
According to the BCC research report of the market research company, the global automotive sensor output value in 2005 was US$10.5 billion, and it is expected to increase to US$14.2 billion by 2010, with an average annual growth rate of 6.1%. The earliest on-board sensors are mainly used for driving state monitoring such as engines or drive systems, mainly including sensors for oxygen, fluid, temperature, ground pressure and current.
As the automotive market continues to improve the requirements for driving safety, comfort and handling, the requirements for various sub-systems for safety, comfort and environmental protection are becoming higher and higher, so as to improve the various functions of safety functions. It accounts for more than 50% of the total number of sensors and has the highest annual growth rate of 13.7%. Therefore, from the perspective of vehicle safety, sensor applications are extremely critical electronic components.
The second is the vehicle power sensor, including speed and oxygen sensor growth rate of 6.7%, pressure and acceleration sensor of 5.7%, air flow, temperature and other sensor growth rate of about 4.6%, annual growth rate of about 6.2%; Among all sensor components, the highest value is measured by speed and oxygen sensors, which is expected to increase from $6.2 billion in 2005 to $8.6 billion in 2010.
In addition, in the automotive image sensor, according to iSuppli statistics, automotive CCD (CMOS) image sensor in the entire sensor market, only about 1% market share. However, it is expected that by 2007, the compound growth rate will exceed 40%, and the total sales volume will exceed 11 million. In the future, at least 5 to 10 image sensors will be installed in each car, and 10 images will be equipped with one car. Sensors, automotive image sensor market size of up to 1.6 billion US dollars.
2. Reduce the accident rate
Since the development of automobile safety, the ultimate goal is to reduce the accident rate, which is one of the most important indicators since the development of automotive sensors. The average person's forward field of view is about 180 degrees. However, the three-way mirrors on the car are only 40-50 degrees of rear view, not to mention the large vehicle can provide the driver's visual range; therefore, the rear of the vehicle Dead corners such as sides are also the main cause of accidental rubbing.
According to data from the US Automotive Safety Research Report, in the North American automotive parts market, the annual sales of rearview mirrors are conservatively estimated at more than $250 million. In other words, American car owners replace millions of rearview mirrors each year, or in the car. New rearview mirrors are added to each part to improve the visibility of the rear of the car.
However, there are many reasons for the blind spot in the rear of the car. It may be because the angle of the rearview mirror is not adjusted correctly, or the rear axle of the car structure is covered by the driver's view, or the large luggage is used to cover the driver. Rear view.
In addition, the current trend of automobile exterior design is moving towards a high waistline. Each newly released car exterior door side window is higher, the driver's vision is increasingly invaded, and the need for blind spot detection equipment seems to be also getting bigger.
Therefore, many sensing technologies and even radar technologies have been applied to automobiles in order to improve the safety of driving. In many sensor technologies, if the most reliable sensing technology can be found, it will not It is subject to bright and dim light, or fog, rain, snow, etc., and even environmental conditions such as air pollution and dust.
3. The main application of vehicle sensors in automobiles
3.1 brake system
Based on the consideration that the car must have a smooth and safe driving, taking the brake system of the vehicle as an example, in addition to using a large number of positions, displacements and pressure sensors, the four-wheel control of the car is generally equipped with an explosion-proof brake lock brake system (AnTI Lock Break). In addition to System; ABS), most of the domestically produced vehicles have been equipped with Electronic Braking-pressure DistribuTIon (EBD), which can greatly improve the stability of driving in bad weather conditions such as rainy weather and snow.
At present, the premium car is further equipped with an Electronic Brake Assistance (EBA), which automatically detects the speed and strength of the driver when the brake pedal is pressed in an emergency, and determines whether the emergency brake is strong enough. When necessary, it will automatically increase the braking force and enhance the performance.
3.2 Driving comfort and convenience is the driver's greatest driving pleasure.
The equipment and equipment of many high-end and luxury models tend to be humanized, not only highlighting their status status, but also improving driver safety, comfort and convenience. For example, with the driver's driving habits, height and weight, using the displacement sensor and micro-valve control, the seat and mirror can be adjusted to the driver's most comfortable state and recorded, and the best driving can be considered. Vision.
In addition, you can also use image, distance, ultrasonic or laser sensors, and then inform the road information through display, warning and other equipment, in order to help drivers reduce blind spots and visual field dead angles, maintain optimal distance and facilitate on-street parking control and reversing action.
In terms of ride comfort, sensors such as temperature, humidity, air volume and sunshine can also be used to automatically control the air conditioning system, maintain a comfortable thermostat system in the car, and use the photometric sensor to automatically control the brightness of the lamp, and also use raindrops and The defogging sensor automatically controls the front and rear windshield wipers to operate automatically.
3.3 Automatic detection and self-maintenance ensure airbag reliability
Airbags use micro-acceleration or micro-inertial sensors to monitor and measure. They must be turned on in real time and correctly at critical moments to maintain passenger safety, but the airbags are on standby for most of the time. The ECU of the airbag must have automatic detection and self-maintenance capabilities to continuously confirm the reliability of the normal operation of the airbag system, and ensure that the airbag can protect the driver in an instant action.
3.4 Intelligent monitoring application in vehicle computer system
The new on-board computer monitors the car, just like a flight recorder on an airplane. After the actual installation, the system's acceleration sensor and gyro sensor can monitor the speed of the car, the use of the seat belt and the cause of sudden turn, emergency braking, unstable running, abnormal deceleration and unsafe reversing. The super-gravity driving, as long as the car is driving in an unsafe state, such as: speeding, super-gravity driving, no buckles, etc., the recorder will give the driver a warning sound, if the driver ignores the warning, then The alarm will repeat until it enters a safe driving state, providing guidance and warnings to the driver.
3.5 Promote fuel system to achieve fuel economy, low pollution and high efficiency
In general, the vehicle electronic system is composed of various electronic control units, which not only have self-maneuvering ability, but also have coordinated and integrated functions to achieve optimal working efficiency for each subsystem in the vehicle. Taking the fuel system as an example, in order to make the engine in an optimal working state, the flow rate of the suction cylinder is measured by the flow sensor, and the pressure sensor measures the intake pressure.
According to the working environment parameters such as water temperature and air temperature (using temperature sensor), the basic fuel injection amount is calculated, and at the same time, the throttle valve position sensor is used to detect the opening degree of the throttle valve to determine the working state of the engine, thereby controlling and adjusting the optimal fuel injection. Finally, it is necessary to monitor the crank angle and engine speed through the crankshaft angular velocity sensor, and use the knock sensor to monitor the engine vibration and combustion noise signals, and finally calculate and issue the optimal ignition timing command.
The engine fuel injection system and integrated ignition control system can also be combined with a gas concentration sensor to monitor the system exhaust emissions and combined with a starting system to optimize the horsepower and torque of the vehicle while minimizing fuel consumption and exhaust emissions. Intelligent system.
3.6 Vehicle sensing products that automatically monitor, adjust and feedback messages
All kinds of functional components in the car have their handling and movement characteristics. For automotive electronic products, they are in a complicated driving environment for a long time, and they are different. Such as high temperature during working conditions, low temperature when standing still, high concentration of oil vapor and active (toxic) gas, and high-speed motion and high-intensity shock and vibration. Therefore, the electronic components and circuits on the vehicle must have the ability to stabilize, resist environmental and automatically adjust, monitor and feedback fault codes.
4. Millimeter wave radar, night vision sensing system into the safe driving ranks
On the car dashboard, there is a radar screen that is often seen in movies. There are small flashes of light on the back. In fact, the way the message is displayed on the car and the need to avoid providing too many unimportant messages to the driver are also designed. Focus.
The so-called "vehicle radar technology" simply means transmitting a very high-frequency radio wave and then detecting the inter-vehicle distance and the position of the vehicle by receiving a millimeter wave reflected from the preceding vehicle or the like, plus The algorithm improves the receiving sensitivity of millimeter waves.
Once there is no object in the detection range, there is naturally no reflection signal. If there is an object in the detection range, the reflection signal is strong, and the radar system measures the time it takes to send the signal to receive the reflected signal. The farther the object is, the longer the gap between transmission and reception is, and the distance of the object is calculated in this way.
However, in terms of the current cost structure, although it is much cheaper than in the past few years, there is still a distance from the expectations of the car manufacturer. According to the insiders of the car factory, if the cost of the millimeter wave radar can be reduced, it will be easy to popularize, but this has a considerable gap with the current cost, and the difficulty is very high.
In order to solve the problem of poor visibility at night, infrared rays are generally used as an auxiliary light source. However, due to the current high price, most of the current night vision systems are limited to certain advanced models. Most of the night vision systems used in automobiles are mainly near-infrared and far-infrared.
The feature of using far-infrared is that it will not glare when it encounters the headlights, signal lights and road signs of the opposite vehicle, and will not be mutually accommodating when the opposite vehicle is equipped with a far-infrared night vision system. interference. Compared with far-infrared image sensors, near-infrared night vision systems can be completed at a lower cost.
5. Functionalization, modularization, intelligence, miniaturization will be a new way to develop automotive sensors
Nowadays, almost all the mechanical structures and components on the body have been controlled by electronic devices, but because the space available in the car is too narrow, the component system space is more limited. Therefore, under normal ideal conditions, the electronic control unit should be tightly integrated with the controlled components to form a whole. Therefore, miniaturization and modularization of circuits and components are inevitable trends, and from the engineering point of view, miniaturization of sensor components has its advantages.
The development trend of vehicle sensors developed by MEMS on modern automobiles should be developed in the direction of multi-functional, modular, intelligent and miniaturized technologies.
In order to strictly control the stability and quality of electronic products on the vehicle, many auto manufacturers have strict requirements on reliability and reliability. Therefore, many important active components of automotive sensors have been provided by fixed suppliers, including: Freescale, Infineon. , STM, Renesas, Toshiba, NEC and other first-class supply chain automotive electronics manufacturers.
If you want to cut into the field of manufacturers at this time, in addition to having to face the competitive pressure of international manufacturers, the challenges that manufacturers must overcome include: digital and analog technology integration, car gauges in temperature, humidity, shock resistance, product life Standard requirements such as the cycle, as well as the patent barriers controlled by the above-mentioned manufacturers, both in terms of equipment quality and technology, have entered a major challenge in the field of automotive sensors.
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