Today no one can be surprised by the abundance of electronics in the car, especially high-class - in "Lincoln" model Mark VIII only more microprocessors, than on any other modern fighter. The automotive electronics market is one of the four most rapidly growing sectors of the electronics industry (after the telecommunications, computer and industrial equipment), which, in turn, is the fastest growing on average 8 to 10% in year - the largest sector of the global industry. Moreover, the cost electronic devices abroad is not in service devices (radio, burglar alarm, etc.), and the controls actually the vehicle systems and safety.
Their share in the cost of a modern car has also increased, reaching now the average is 10...15%, although analysts and predict a stabilization in the near future at the level of about 20...25%. However, continuous the reduction in unit cost of electronic devices (in terms of a single function), there can be no doubt that the number of functions performed by electronic the devices in the car, and their diversity will be steadily expanded and further, at least up until the consumer will be able to take advantage of.
With the gradual restoration of ties between the Russian and world economy imbalance between the prices of electronics and other engineering products that existed in Soviet times, rooted in the past. Along with this the need to simultaneously improve efficiency, environmental impact and improve ride quality is relevant for domestic automobile plants.
Firstly, it is due to the fact that the export of obsolete products in developed countries becomes almost impossible, even at low prices, and enterprises need hard currency to pay for imported components. Second, in recent times in our country were taken and soon to be introduces appropriate world more stringent standards on permissible levels of air pollution and the safety car, which will bring us to the conditions prevailing in the global automotive market.
In this regard, the appeal to the experience of the world automobile industry looks absolutely natural and justified. We now vases completes electronic systems injection control and ignition more than 40% of produced cars.
Currently, the most important and economically justified is wide the introduction of electronic systems to improve the performance and reduce the cost of operation of the engine and transmission, as well as systems to improve security - active (ABS - anti-lock braking system (AntiBlocking System), APS - traction control system )and passive (pillows security). In addition, developed and are being used by other electronic system - suspension control, navigation, Parking etc. but they are more of a luxury than a necessity.
For a long time the only electronic unit in the car except the radio, was the ignition system. Classic spark ignition system was first proposed Philippe Lebon in 1801, and the first industrial application it found on a gas Lenoir engine in 1860-1864, However, due to low level electrical engineering of the time spark ignition did not work. Therefore, to the 90-ies of the last century, the majority of internal combustion engines built with the use of pre-ignition (very hot body in the combustion chamber).
The situation changed with the creation of the Robert Bosch completely reliable and compact magneto. Further, in the 10-ies of our century improving the design spark plugs, ignition coil and materials selection contacts managed to achieve satisfactory performance on battery and ignition system. The less than it, especially the contacts, still remained one of the most unreliable and maintenance-parts vehicle. Needed breakthrough solutions.
The first electronic ignition systems were created in the 1940-ies on the basis of gas-filled thyratrons, however, wide use is not found because bulkiness and fragility of the design. The massive use of transistor system ignition - first contact, contactless then - found in the early 1960s years, when General Motors Corp. (GMC) was to equip them your serial the vehicles.
Further dissemination of electronic ignition systems is well known. Separate interest is the system with high-frequency discharge, Direct Ignition (SAAB), borrowed from jet engines. When creating those used the fact that the breakdown voltage for high frequency (80...200 kHz) voltage is two to three times smaller than for low-frequency, and instead thin threadlike spark is obtained spherical discharge with significantly greater surface.
The low voltage makes the system less sensitive to fouling and sludge on the plugs, and the spherical shape of spark discharge accelerates the ignition and improves the reliability of ignition of the poor mixtures. However, structural complexity and the higher cost of this system, and that it generates abundant radio interference, led to the withdrawal of its production after the introduction of systems injection with electronic control(Conditions of work and candles ignition system in General on these engines a lot easier than for gasoline) .
Contrary to popular belief, the fuel injection is also not a new by the invention. Moreover, initially, almost all of the engines internal combustion engine operating on liquid fuel, was just used system the injection. However, it soon became clear that it requires a fairly complex mechanism regulation of the fuel injection quantity and fuel dosing pumps, manufactured with high precision. At the beginning of this century are very expensive, at the same reasonable price did not provide the required reliability and stability characteristics.
Therefore, after the invention of the Banks or given simple and cheap spray carburetor of fuel injection systems in the automotive industry almost forgot. They remained only in diesel engines, the increased cost of which, by the way, in owes much to the high cost of the equipment direct injection high pressure. Mechanical devices injection control due to their high prices public vehicles is almost not used. The first system with electric the office was first created in 1939 (Moto Guzzi, Italy), but has remained technical exotic.
In 1957 Chrysler firm introduced the car electronic system control of fuel injection performed on the vacuum tubes, also not found wide application because of the high cost. More common in the early 1970s the years have gained a transistor system used in German (Volkswagen, 1967) and Japanese (Nissan, 1971) cars exported to the USA. At the turn of the 70s and the 80-ies in Japan, USA and later in Germany have started to introduce integrated microprocessor control system as jet
The carburetor has many shortcomings: the instability of adjustments, especially when changing the temperature and type of fuel; the uneven distribution of fuel cylinders; low accuracy at low loads, driving to configure the carburetors so that at idle and low load fuel mixture unnecessarily enriched. In addition, the carburetor increases resistance to the absorption of air. Because of the presence of the float chamber work carburetor worsening in the conditions of strong shaking, acceleration in curves and when the slopes of the car.
From time to time, these disadvantages in relation to mass cars were perfectly offset by the simplicity and cheapness of carburetors. Nevertheless, in expensive cars, but also in piston aircraft since the end of the 30-ies has there been a return to the use of fuel injection systems with mechanical control. They were very complex and expensive, but allowed to increase the economy and stability of engine operation.
However, as more stringent requirements for environmental clean exhaust and facilitation service of mass of the vehicle, to ensure their implementation the improvement of the carburetors were already virtually impossible(Model demand in the U.S. market is the need to ground IT to the engine and transmission not earlier than 80...100 thousand miles on the odometer). The essence of the problem is that if the fuel mixture is poor, she is poorly ignited, unstable burns, prone to detonation and combustion gives a lot of nitrogen oxides NOx. Once in the atmosphere and soedineni with water, these oxides form nitric and nitrous acid.
If the fuel in the mixture is greater than can be burned in existing the amount of oxygen, incomplete combustion of fuels leads to emissions hydrocarbons CmHn, carbon monoxide CO, benzapyrene, aldehydes, and at even a larger excess fuel and highly carcinogenic soot (smoke). With a strong violation of the ratio between the quantities of air and fuel air-fuel the mixture ceases to ignite that, no doubt, familiar to many to motorists.
Sharply - more than ten times to reduce the amount of harmful emissions, using the catalytic Converter (the Converter), exhaust gas, however, for his work required a very specific composition of the exhaust gases. In particular, the Converter does not suffer the work of leaded gasoline. Violation of these terms leads to irreversible output of the down Converter.
However, the emergence and rapid depreciation of microprocessor technology has allowed to create the fuel injection system for gasoline engines, first, not requiring expensive precision mechanical devices, and, secondly, with significantly greater capabilities than mechanical. As a result, the use of electronic control fuel injection and ignition of fuel from the end of 1980-ies in developed countries became economically justified on cars almost all the classes.
Injection system with electronic control (EFI - Electronic Fuel Injection) at sensor oxygen content in the exhaust (l-probe) allows to ensure that each cylinder is very stable (+0,5%) compliance with optimal the ratio by mass of fuel supplied and sucked in air (1:14,65 to gasoline). This is necessary to ensure the operability of the catalytic Converter and to achieve the best compromise between power and the efficiency of the engine. Therefore, to ensure in practice long service life and the efficiency of catalytic converters it is possible only when using
The fuel injection system is conventionally divided into three groups: Central injection when the injection nozzle is one for the whole intake manifold( Sometimes it is necessary to complement the second - launcher nozzle operating at cold the engine and turning off as you warm-up) , with distributed (multi-point) injection, if the nozzles are mounted at the suction nozzles each cylinder close to the intake valves, and direct (direct) injection, when the nozzle is mounted directly in the wall or the cylinder head and takes the the fuel directly into the cylinder in the compression stroke, when the valves are closed.
In the first two cases, the fuel pressure in the delivery does not exceed 4...10 kg/cm2 whereas with the direct injection in a diesel engine it can reach 600, and in the gasoline engine 50 kg/cm2.
The cheapest system with Central injection - actually gives only two significant advantages of the vibration and no need for frequent adjustment. The best relation price/quality currently provide fuel injection system into the intake branch pipes (Fig. 1). System direct injection in gasoline engines is justified only in so far supercharged engine, as they allow you to exclude the removal of the air-fuel mixture in the exhaust manifold with the broad valve timing and absolute the boost pressure of 1.5 kg/cm2.
There are also systems of continuous and pulsed (intermittent) injection. In systems of continuous injection nozzle operates continuously, changing only its performance, pulsed injection of fuel is effected portions in certain moments. Continuous injection has many flaws and is currently time in relation to automobile engines it is considered obsolete.
The use of injection provides other advantages over the use of carburetors. Firstly, it is the ability to provide a high the stability of the air-fuel mixture in a wide range of temperatures and loads engine, almost regardless of fuel viscosity (flow the ability of the nozzles of the carburetor strongly depends on the viscosity of fuel). Secondly, the use of multi-point injection (especially direct) allows only to ensure uniform distribution of fuel in the cylinders, but also to exclude the necessity of heating up the intake air and the intake manifold. More in evaporating fuel, on the contrary, cools the intake air and cylinders of the motor. As a result, the density of the intake air is at 7...10% more (With the same goal of reducing the temperature of the air - even on the cheap cars with fuel injection are trying to suck air from the engine compartment, where he's hot, but directly from the street, providing for this in the case the need for additional air intakes (Opel Cadett") .
The increase in air density, and therefore the amount of oxygen entering cylinders, allows you to burn more fuel and get more power. Lowering the temperature of the intake air can improve the compression ratio, it improves the efficiency of the engine.
Exception carburetor reduces the resistance of the intake air, giving the use of resonant intake, which also helps to increase power. The approach of the nozzle to the cylinder in the injection systems prevents condensation of the fuel. This facilitates the starting of the engine, reduces the formation of carbon deposits on spark plugs and flushing oil from the walls the cylinders.
No condensation of fuel increases the stability and torque the engine, especially at low and medium engine speeds where it is most needed. If increase maximum when the translation engine to fuel injection usually equal to about 10%, then increase the torque at low and medium engine speeds can reach 15 to 20%.
Of course, the increase in the driving characteristics can be achieved and "head", increasing the working volume of the engine by about 20 to 30%, but will deteriorate efficiency, increase the weight and dimensions of the engine, and hence of the vehicle in General, will increase operating costs.
The use of injection systems to provide another opportunity reduction of fuel consumption - off the fuel supply to the cylinder portion, to the greatest extent possible to upload the rest. The rationale for this decision due to the fact that at low load efficiency of the internal combustion engine dramatically reduced not only due to the mechanical losses, but also due to the nonoptimality operating cycle. Increase the efficiency of loaded cylinders to more than compensate for mechanical losses in a switched-off cylinders, so the efficiency at low stresses can increase by 25 to 30%, especially on multi-cylinder engines.
A similar technique - alternate skipping cycles of injection is also widely used in multi-cylinder Japanese and American cars. There is another one application of the method of skipping cycles - cooling disabled cylinders sucked in by air, which helps to maintain the efficiency of the engine and to get to the destination even after a complete loss of coolant (engine GMC North Star, etc.).
The use of electronics ensures optimal control of not only the engine, but the car chassis. First, it is well known anti-lock braking system, allowing in most cases save machine control in emergency braking, while simultaneously providing minimum stopping distance. Secondly, have a close function perform traction control systems, which have become highly relevant in connection with the proliferation of front-drive cars, which when slippage or locking wheels controllability is lost. Since when overclocking the car's front wheels are unloaded (that is why all racing and prestigious cars that must have good driving dynamics, to date design with the drive or on the rear ("Daimler-Benz", "BMW"), or all-wheel drive ("Audi A8"), to avoid loss of control and prevent excessive tire wear it is highly desirable to the front wheel drive car along with anti-lock and traction control system.
Using electronic devices also smoothed the antagonism between boxes change gears with automatic and manual switching. Recall that classic auto box to ensure a smooth switch requires the use of expensive to manufacture and cumbersome torque Converter, it has a large mechanical losses (low Efficiency). Box same transmission with a manual shift structurally much simpler smaller, cheaper and more reliable. However, it is less convenient in operation.
The complete control system for the engine and transmission automates the process gear changes without the use of torque converters and more clutch - by automatic control of the clutch and rotation speed the engine, while maintaining all operational advantages as automatic (convenience) and manual boxes (reliability, low cost, small loss of energy). In addition, the electronic control virtually eliminates the risk of breakage due to incorrect handling.
Such transmission at cost of manufacture is not different from the transmission with manual control, and management functions it usually integrated into the composition United engine management and transmission. Algorithms gear shift in recent times often build adapts to the driving style specific owner, not to mention the fact that always provides a choice of several standard modes (high-speed, urban, economical, etc.).
An equally important role in a modern car play electronic systems increase security. It can be subdivided into active (prevention accidents) and passive (reduce the severity of their consequences). With regard to active security, provide improved acceleration and braking dynamics car and increase cornering stability maximum the wider track and lower center of gravity (which is very obvious, if to compare the silhouette of domestic and foreign cars of similar class, for example, VAZ-2108 and Volkswagen Golf III" or "Golf IV") in combination with electronic suspension control.
Expensive cars are sometimes used radar prevention system head-on collisions and collisions (maintain a distance), but from the logs or holes in asphalt, it does not save. To reduce the likelihood of assaults use the upper (salon) brake lights, visible at a great distance. It was not enough, and then the system was developed with the radio transceiver automatically including the indicator in emergency braking or crash the car in front. Currently this system, which received the gold medal of the exhibition of inventions in Brussels is being finalised with further standardization in most the developed countries.
Improve driving dynamics, in the first place, the introduction of electronic systems fuel injection and transmission control (microprocessor can switch transmission is much faster and more accurately than a person; as a consequence, the acceleration of a car accelerating) , and on front wheel drive cars - and even improve the rubber compound and tread of the wheels, brake - applying anti-lock braking systems to prevent excessive wheel slip on the road, allowing you to get the maximum possible braking the effort in most cases to keep the car's handling even when emergency braking.
A certain contribution to the improvement of active safety makes steering power steering with variable ratio transmission and steering response for equal rotation of the wheels at high speed requires a greater angle steering than in Malaya. Sometimes further added device, to prevent failure of the wheel lateral force. This virtually eliminates the risk skidding when making a sharp turn at high speed. All of these advantages, however, persist only as long as the servo is working properly....
Passive safety increase as constructive measures (increasing stroke deformation of crushable parts of the body while strengthening salon, replacement conventional collapsible steering) and the introduction of electronic devices, activating the airbag and the belt tension device. By the way, the widespread introduction of electronics in cars in the United States began after at the turn of the 60-ies and 70-ies, the Congress adopted a law on the mandatory installation systems that block the starting of the engine until, until you have recorded harness straps on the two front seats.
Currently, typically utilize an integrated management system seat belts and airbags. The sensor in it is uniaxial (or biaxial when you use and side airbags) accelerometer, most semiconductor (Fig. 2), the control unit with the threshold device and a set of cutters, part of which, when activated acts on the impeller, pull-up straps (Fig. 3), and part - fills the airbag. The inclusion of the cutter mechanism suspenders belts usually set somewhat earlier than the time triggering of the airbags.
This system allows you to escape shock, scratches or bruises when a head-on collision with a fixed obstacle at a speed of 50 km/h (standard UES), and sometimes more - up to 80 km/h At speeds above 80 km/h the acceleration experienced by the person at the time of clearing the energy of motion on the way, about 0.7...1.6 m (typical progress of deformation of the body and pillows modern cars) becomes so great that it is crushed by his own weight even in the absence of external damage.
Speaking of electronic systems increase security, it is worth mentioning a simple but very useful device health check warning lights and the wiring. The principle of its action is that through the lamp and wiring when the ignition pass a small current that does not cause the illumination lamps, but for diagnosing circuit, breakage of the wiring and the status of the lamp in the end-of-life resistance of the filament increases that in advance serves as a warning to the driver.
Recently certain popularity, at least on cars class is above average, began to acquire the use of electronic control the parameters of the suspension stiffness and damping coefficient of the shock absorbers, the change in ride height. A suspension is often called active, although really we are only talking about a relatively slow adaptation of the parameters suspension for road conditions, i.e. rather be considered adaptive or semi-active. True active suspension system, strictly speaking, must use powerful servo to track every bump and to absorb shocks at the time of their occurrence as it happens on comfortable ships and many military ships ("the instigators" pitching).
In Europe and even, perhaps, in the world the leader of the "podcastready" - firm Сitroen, long and applies the most advanced - hydropneumatic - suspension in combined with electronic control their parameters. Among Japanese firms the leader seems to Mitsubishi. The Americans, with excellent roads and 55-mile the speed limit in most States, prefer a more traditional solutions - increased size and, hence, the moment of inertia of the hull cars combined with large diameter wheels and soft suspension, in which electronic systems typically control only the damping ratio.
The use of electronic devices has also improved a number traditional devices, primarily actuators (wiper, Windows, adjusting the position of chairs, etc.), lighting and signal devices. Traditionally in automotive technology use collector motors that are characterized by three main drawback - limited term service, lack of reliability (the tendency to jam) and the creation of radio interference. These shortcomings are due to the use of rubbing contacts in the manifold. The development of electronics has led to the fact that contactless (brushless, brushless) motors have become cost competitive with traditional, surpassing them in terms of reliability, adaptability to the production and opportunities adjustment.
Broad management capabilities simplify the kinematics of a number of devices, for example wiper, where instead of a mechanical reversal can be applied electric. Therefore, at present almost all the leading automotive firm gradually replaced in their cars the commutator motors on contactless and have the advantage that their the control units can have an interface for direct control from the microprocessor.
With regard to lighting, the introduction of the increasingly popular metallogenic hid lamps would be simply impossible without use of electronic components management. The main advantages metallogenic bulbs compared with incandescent bulbs are substantially smaller luminous the field, which reduces the size of the reflector headlamps with maintaining quality the focus of the beam, to achieve the best efficiency (greater light output at equal the power consumption), stable spectral and brightness characteristics regardless of the degree of discharge of the battery, as well as durability.
Another electronic system that improves traffic safety, is concealer headlight position, providing irrespective of load and position the body of the permanent illumination of the road when driving on rough or winding the roads, in the latter case, it monitors the rotation of the steering wheel. In addition, corrector reduces glare of headlights of oncoming cars.
Signal lights on many American cars recently performed on the basis of blocks of high-brightness LEDs. They are more economical, more compact and more reliable traditional incandescent lamps, especially in flashing mode to provide greater the brightness and cleaner colors (better visible in the daytime). Brightness LEDs are easier to change depending on the ambient light.
Sound signals do not remain without attention - the traditional contact electromagnetic horns come contactless electrodynamic and piezoelectric with corresponding electronic amplifiers and nodes management.
The emergence of processors for digital signal processing and a gradual decline in the prices of these devices led to the creation of systems of active suppression of low frequency noise in the cabin of the car. The essence of the idea is to flow into the cabin through loudspeakers built-in audio signals, out-of-phase noise. When this noise signals cancel each other out.
In practice, due to the wave properties of sound desired effect can only be received at a frequency below 200...300 Hz, and the noise reduction does not exceed 8...15 dB. It seemed would a little, but considering that the fight against low-frequency noise in other ways ineffective, such electronic system allows you to save 10 25 kg... the deadener Dynamat or other material, not cheap.
The widespread introduction of e-governance in the traditional approach leads to sharp complication of wiring, and thus increase the complexity of its strip and the probability of errors during maintenance in operation. The abundance wires threatened to turn the car into a "Cabinet" on wheels. In search this problem, automakers have turned to aviation experience: one time the mass of cables reached 30% of the weight of the electrical equipment aircraft and had a tendency to further increase.
The problem was solved by introduction of systems of the form "General line serial", when most electronic devices connect interconnected in parallel through a common three-wire interface, and the exchange information between them by the same wire, but are separated in time, in the same way as it happens in computer networks Ethernet.
A similar solution called multiplex wiring in the early 90-ies steel used in the automotive industry. Initially, as usual, was the "war of standards", which appeared J1850 (SAE), CAN (Controller Area Network), CarLink, a VAN, A bus, etc. To date, most attention was given to the CAN standard, jointly developed by Bosch and Motorola. It delivers transfer speeds up to 1 Mbps and allows be used to transmit information as copper wire, and fiber optics.
Author: S. Ageev, Moscow