Safe, comfortable, free from contamination, economy is auto industry and the objective that the user pursues all the time. The electron that realizes the key of these targets to depend on a car is changed and intelligence is changed, precondition is all sorts of information is seasonable get, this certainly will asks to use all sorts of sensor in great quantities in the car. Traditional sensor often bulk and weight are great, cost is high, they get in the application of the car very big limitation.
In recent years from semiconductor integrated circuit (the MEMS (Microelectromechnical System that IC) technology develops and comes, microelectronics machine system) the technology is mature with each passing day. Use this one technology to be able to be made all sorts of can sensitive and detect the miniature sensor of mechanical quantity, magnetics quantity, heat quantity, chemical quantity and biomass, the bulk of these sensor and specific power consumption are small, can realize a lot of brand-new functions, facilitate large quantities of quantities and high accuracy are produced, odd a cost is low, easy form large-scale and muti_function array, these characteristics make they special agree with the application of car respect.
At the beginning of 80 time, multichannel of type of miniature pressing block is absolutely pressure (Manifold Absolute Pressure) sensor begins large quantities of quantities to produce, replaced inchoate the pressure sensor that uses LVDT technology. Sensor of acceleration of miniature of 80 time metaphase begins to be used at automobile safety gasbag, they are so far mass-produced, the miniature sensor that gets applied extensively in the car. However the large-scale application situation of miniature sensor is sure not control of combustion of engine of be confined to and safe gasbag, in future 5 ～ include engine to run management, waste gas and air quality control, ABS(antilock Brake System inside 7 years, prevent adopt dead system) , car is kinetic control, get used to system of security of travel of navigation, car oneself (if gasbag and fraise detect with avoid bump etc) inside application will be MEMS technology to provide broad market.
The car output of the whole world will 47.5 million from 2000 (include passenger car, special purpose vehicle and light-duty truck) growth goes to 54 million of 2005. The car was 22.7 billion dollar with the market of electronic product 2000, predict to reached 30.9 billion dollar 2005, year average increase rate is achieved 6.3% . The cost that every corresponding car costs in place of electronic product side raises the 572 dollars 2005 from the 477 dollars 2000.
According to document report, the market of car sensor was 6.17 billion dollar 2000 (904 million products) , will reach 8.45 billion dollar to 2005 (1.268 billion) , increase rate presses dollar plan for 6.5%() press a product with 7.0%(number plan) . North America place held share of car sensor market 2000 the biggest, for 47% , it is Europe respectively next (26%) , japan (22%) , with Korea (5%) .
Speed and positional sensor take market of sensor of all 2000 car (with the dollar plan) 38% , it is aerobic sensor next (sensor of mass flow of 20%) , air (13% ) , accelerometer (11% ) , pressure sensor (10% ) , temperature sensor (5%) etc (3% ) .
The main growth domain of sensor of 2005 year car includes 2000 ～ the following respects: Use at car the accelerometer of kinetic control and safe gasbag; Use at the pressure sensor of the respect such as transmission, brake, cooling, tire, fuel; Use at car trends control, to turn over calls the police and the crab rate sensor with mothball GPS; Use at annulus fast and the positional sensor with sensitive position of camshaft, crankshaft, footplate; The humidity sensor of monitoring of railroad car environment; Solar, rainwater and humidity sensor; With the range finding sensor that bumps at close quarters fraise detects and avoiding.
Car assembly needs to satisfy the requirement of the respect such as multinomial environment, dependability and cost. Specific for, they on one hand must the test that can undergo interference of all sorts of high low temperature, oscillatory, concussion, damp, caustic atmosphere, electromagnetism to wait for adverse element; On the other hand also must comfortable produce at large quantities of quantities, should achieve commonly annual million above, this is the demand that car volume produces not only, also be to call in design and the mint investment place of production respect are indispensible. In addition, its dependability also should be as high as 10 years with the car / 150 thousand miles service life photograph is consistent. Altogether, car assembly is " army tasted quality, civilian tasted price " .
Sensor of great majority miniature uses silicon data. Well-known, silicon material obtains very tall purity easily, have good mechanical performance and weight is lighter, itself has the photoemission, effect that control block and suddenly Er effect to wait for a variety of passing to feel characteristic, and facilitate the signal that make is sensitive as compositive as processing circuit sensor. The mainstream technology of miniature sensor is craft of treatment of instrument of silicon radical personal computer, it originates already mature semiconductor technology, can machine an a large number of almost identical rigid structures at the same time. Accordingly, besides have volume small, weight light, specific power consumption is low outside the advantage, the reliability of miniature sensor is higher, it is OK also that its offer commodity price check far under the sensor that uses traditional Electromechanical technology and technology. MEMS technology certainly will will make the mainstream technology of car sensor. The sale that report of the closest Roger Grace Associates/Nexus estimates to the car uses MEMS product will raise the 2.27 billion dollar 2005 from the 1.75 billion dollar 2000, year all increase rate is 16.9% .
Because be based on the miniature sensor of MEMS technology,reducing car electron system cost and the dominant position that improve its performance side, they had begun to replace the sensor that is based on traditional Electromechanical technology stage by stage. The sensor place that absolutely pressure sensor changes already basically for miniature replaces inchoate multichannel, the sensing element of this kind of sensor and signal processing circuit are already at present OK compositive go up in same chip, narrowed volume can rise greatly thereby dependability and reduce interference.
In other pressure quick induction is used, especially in harsh environment (in starting engine oil and radiator refrigerant like park) , use the switch of pressure of type of capacitance of pottery and porcelain that discrete element makes commonly, they will be used stage by stage now the silicon strain gauge that bond honest legal system makes (secure commonly in cost is low and solid enclosing) or pressure quick resistor chip (in installing what taking stainless steel diaphragm to carry a lid to be full of the silicon of silicone oil to make case) be replaced. The firm that can offer this kind of product at present has Keller, measurement Specialties, SSI Technologies, Fasco and Integrated Sensor Solutions(ISS)/Texas Instruments. Mass flow sensor is made with the hot line of schism normally, and the sensor that the miniature that at present Bosch company uses method of instrument of exterior personal computer to make changes has shown its distinct advantage. Be used at safe gasbag bump sensor to already conformed to the principle of simplicity odd " ball, canal " (evolution of sensor of type of Ball And Tube) is changed for miniature and compositive accelerometer, current main firm has ADI, motorola, sensoNor, wait with Nippondenso. Among them the miniature accelerometer product of Motorola is shown 2 times like the graph. Amount of this external use is very large annulus fast sensor (use at ABS and car kinetic control) also will by change traditionally magnetoresistive of Xiang Huoer type, anisotropy compares magnetoresistive style (AMR) and gigantic magnetoresistive are compared (GMR) type develops. Above analysis and example specification miniature are changed is existing car the main way that develops with sensor.
This section will be in to miniature sensor the main application direction in the car undertakes an analysis, they include safe system, raise comfortable sex / convenient sex / guard against theft, engine / drive catenary and car monitoring and diagnose oneself wait for 4 respects.
Safe gasbag is at present and a in the future also is MEMS main application. Uses silicon base the span of accelerometer is 50g commonly. Besides ADI company, general accelerometer still is formed by much chip package, provide the signal that passes recuperation. ADI uses relatively advanced sheet piece law of type collect set prescription, make acceleration sensing element and corresponding signal recuperate circuit at the same time on same chip, if pursue,3 are shown.
Many manufacturers already compressed air to replace the natrium with the commonly used place when opening gasbag to using base compound dynamite or a kind of complement that serve as it undertook study. Considered to be used at detecting to compress the sensor of air crock pressure for this, but have not apply actually at present.
Pensile system should can change direction in high speed when, when the travel on uneven road surface and it is better that be quickened suddenly and car lets still be had when brake drive function. What a lot of systems use is closed-loop control of total form of characters or letters. Completely active system is very expensive (4000 dollars of 2500 ～ ) , the hydraulic pressure that its use makes gearing will be used up very big one part power, and added weight greatly. Of these systems introduce the performance that improved car really, but also raised cost greatly. The application on the car that accordingly they produce in large quantities of quantities got restrict. Nevertheless, a lot of manufacturers introduced system of suspension of half active pilot. Wh some of which installed displacement sensor on shock absorber and introduced many lines accelerometer. The uses a requirement acceleration span of this respect is the volume level of ± 2g only, they offerred very good opportunity for the application of miniature sensor.
From 1995 Mercedes car begins S class, silicon radical pressure sensor already was used at detecting advocate the pressure of brake air cylinder. Outside sensor of the rate that remove part, steering wheel angle and acceleration sensor, wheel speed sensor are applying at car stage by stage in kinetic control. But, major car uses wheel speed sensor only (ABS, traction is controlled) . Current, the top of instrument of exterior personal computer of Bosch company or Systron
The single price of the sensor of rate of isogon of tonometer type top of Donner and Matsushita is 25 dollars, its application is confined to limousine car, be like Mercedes(S class) , BMW, Cadillac. Many famous car and fittings supplier are devoting oneself to to design sexual price to compare more expensive system. The cheaper horny rate sensor that is based on MEMS technology will conduce to these systems be in the car with lower price application.
Current car navigation system GPS (global location system) and store the electronic map in CD-ROM and wheel rotate sensor and rate top or magnetism compass union rise. But the price of this kind of system is very at present high, it is 1800 dollars about, can serve as only wait for chosen a replacement. In the application of this respect MEMS sensor will produce mainer and mainer effect, their application will make this kind of system is in not far fall in the future 900 dollars are the following.
Watch 2 listed miniature sensor is raising comfortable sex / convenient sex / the application of respect of guard against theft.
Medium pressure measured compressor of car air conditioning to offer very good opportunity for MEMS technology. What what use at present is other technology (the pressure sensor of capacitance of pottery and porcelain that is like TI) . But company of technology of a lot of MEMS is developing corresponding miniature sensor actively, in order to contend for this one very big market.
Watch 3 listed miniature sensor is in engine / the application of drive catenary respect.
The electronic control of engine is considered as MEMS technology all the time one of main application domains in the car. Delco, motorola and Bosch company produced number with 1 million plan multichannel pressure sensor. These parts of an apparatus measure the multichannel inlet pressure that give to be able to use computational air / fuel comparing. People is using air mass flow in the attempt (Mass Airflow) sensor substitutes this kind of parts of an apparatus. The product that sells on the market at present used the measurement technique of wind speed of hot line type of schism, their bulk big, price is high. Bosch company introduced sensor of a kind of new-style mass flow that is based on filmy technology 1995. A lot of organizations are opposite now already this kind of sensor that miniature changes undertakes assessment. Besides multichannel pressure and mass flow parameter, engine controller still needs to get atmosphere force parameter, so that the basis turns the information of height above sea level of cipher out,decide reasonable air / fuel comparing. MEMS technology will produce mainer and mainer effect in these application.
Air cylinder pressure is measured to optimizing engine function for very crucial. Because the temperature inside air cylinder is very high, press report and fiber-optic technology relatively practical, their high nevertheless price restricted his to apply. Waste gas was used to circulate in the car of Ford and Chrysler company at present (EGR) system. In these systems, pressure sensor of type of capacitance of pottery and porcelain is pressing block type sensor for miniature silicon be replaced. Stepless is adjustable the pressure that transmission system needs to measure hydraulic pressure oil. In this on one hand, open the miniature pressure sensor that come to will have wide applied perspective through all sorts of methods and working medium segregation. Fasco, measurement Specialties, integrated Sensor Solutions (is bought for TI recently) developing the miniature sensor that is used at this kind of application with SSI Technologies company. They are compositive have the silicon that passes EEPROM process designing base CMOS ASIC mixes circuit.
Watch 4 listed miniature sensor is in car monitoring and the application that diagnose a respect oneself.
In this on one hand, a of MEMS technology main application will be tire pressure is monitored. No matter will look from safe drive a vehicle or the angle from economic fuel, be necessary to maintain proper tire to fill gassy form. At present already many real time embryoes control the system that monitor. The miniature pressure sensor that is based on MEMS technology is ideal sensitive parts of an apparatus. As Run-flat tire introduce, these measure a system to be installed already extensively in all sorts of new models. The use of Run-flat tire makes people needs to reserve no longer embryo and jack. The United States overcame Lin Du government to already enacted a law, the requirement must install this kind of device to the car carrying a passenger that American churchyard used 2004. This provided a huge market for miniature pressure sensor, lucas NovaSensor, the manufacturer such as Motorola and Sensonor is contending for this one market actively.
Engine monitors the applied opportunity with also offerred significant for MEMS technology oilily. The biggest obstacle of these systematic application is its price. Pressure sensor of this kind of miniature must can be in the engine oil with very high temperature is normal the job, its silicon makes sensitive chip part must be kept apart with working medium. The value that contains the sensor that all signal recuperates circuit and has enclosed should be in 5 ～ between 7 dollars. Pressure sensor still can apply at monitoring easy volatilize the vapour pressure in fuel gasoline tank, do not have fuel steam leak in order to ensure.
Be in before long in the future, the application of car respect will continue to make a of MEMS technology main market. The sensor place that absolutely pressure sensor and gasbag accelerometer are changed already completely by miniature almost replaces traditional nowadays multichannel. In annulus fast measure, force of oil pressure of cooling system pressure, engine and brake pressure measure a respect, people is considering or had begun to use the sensor that is based on MEMS technology to replace already some products. In addition, people still is considering to use miniature sensor in the system of a lot of new development. The advantage of the respect such as the price, dependability and bulk will make miniature sensor makes the first selection product that all sorts of parameter in the car measure. At present these advantages already confirmed to carry out place. The car already was taken seriously with miniature sensor by the height of scientific research orgnaization and manufacturer, OK and fatidical, future 7 years of its development, production and application will obtain 5 ～ high speed grows