Before the popular fuel injection system was used in gasoline engines, the carburetor was the main unit for creating the fuel mixture. The fuel consumption, stable operation of the engine at idle, the durability of the entire fuel system, and the environmental parameters of the engine depend on how it is configured and how the carburetor is adjusted.
Since there are still a lot of domestic cars with such a fuel formation system on our roads, the relevance of these adjustments does not decrease. For foreign cars, the adjustment algorithm will be similar, because the circuit diagrams of these nodes for different car models are quite close.
The carburetor is part of the fuel system of a gasoline engine. In it, air is mixed with fuel in the proportion specified by the settings and is fed into the combustion chambers of the car. There, the mixture is ignited with the help of automobile candles and pushes the pistons mounted on the crankshaft. The cycle is repeated, and in this way the energy of the explosion is converted into rotational motion transmitted to the wheels through the transmission.
The correct setting of the carburetor makes it possible to supply a high-quality mixture into the chamber.
Incorrect proportions lead to detonations, which contribute to the rapid wear of the fuel system elements, inability to ignite, incomplete burnout of gasoline during engine cycles, and, accordingly, excessive fuel consumption.
The carburetor does not require daily monitoring, adjustments and cleaning. Most often, the unit is subjected to such a procedure on demand after using low-quality fuel or with obvious signs of unstable engine operation. You can carry out preventive cleaning or washing after 5-7 thousand kilometers.
Possible problems
You can start diagnosing problems with the carburetor when obvious problems are identified. Most often, the driver can notice fuel smudges. In this case, it is necessary to check the level of fuel pressure. This can be done either at home using a fuel pressure gauge, or at the station for 200-300 rubles. At home, it is advisable to take care of fire safety, and do not spray gasoline in the engine compartment. The value should be at the level of 0.2 - 0.3 atm. The exact parameter can be found in the instruction manual. If the readings are satisfactory, the problem may be in the float chamber.
Step 1. Remove the air intake cover 
Step 2. Adjust the jets 
Step 3. Adjust the traction
Checking the spark plugs should reveal an incorrect setting. If they have soot with a clear smell of gasoline, then this indicates an unadjusted float or a burned-out valve.
The stability of idling can be reduced not only due to the operation of the carburetor, but also due to the operation of the cable connecting the rods on the carburetor to the gas pedal. It is easy to identify this, just disconnect the cable from the rod and crank the throttle without it. If there are no problems with fuel, then the cause may be the transfer of effort from the pedal.
Preliminary preparation and cleaning of the carburetor
Before you adjust the carburetor, you need to wash and clean it. There are special liquids for this.
Do not use oily liquids to clean the carburetor.
To clean the jets, use a soft copper wire. In no case do not use steel needles for this operation, so as not to damage the hole.
Proper carburetor cleaning
Also, do not wash with rags, which can leave a pile on the product. In the future, such residues can clog into the through holes and create problems during the operation of the unit.
Carbon deposits and dirt are well washed off with the help of aerosol sprays, which are sold in car dealerships. For maximum removal of contaminants, it is necessary to rinse the product twice.
Adjusting the performance of the float mechanism
The level in the float chamber affects the quality of the fuel mixture. When it is increased, an enriched mixture will be supplied to the system, which will increase gasoline consumption and add toxicity, but will not add dynamic qualities to the car.
Without checking the performance of this unit, it will not be possible to correctly adjust the carburetor.
The procedure includes the following operations:
- Control float position in relation to the walls and lid of the chamber. This eliminates the possible deformation of the bracket that fixes the float, helping it sink evenly. This is done manually, setting the bracket in equilibrium relative to the body.
- You need to make adjustments when needle valve will be closed. We put the cover vertically, remove the float, and slightly bend the bracket tongue with a screwdriver. With its help, the locking needle moves. It will be necessary to install a small gap of 8 ± 0.5 mm between the float and the cover gasket. If the ball is recessed, then the gap should remain no more than 2 mm.
- Process open valve adjustment begins when the float is retracted. Then the distance between it and the needle should be 15 mm.
Setting the fuel mixture supply
You can adjust the enrichment or depletion of the fuel mixture by adjusting the corresponding jets by turning the control screws. If no one has made any settings with these screws before you, then the factory plastic pressing will remain on them. Its task is to leave the factory setting on the device, although it allows you to turn the screws for adjustment at a small angle (angle from 50 to 90 degrees).
Often they are simply broken out in situations where turning to the allowed angle does not bring results. Before this type of adjustment, it is required to warm up the engine to operating temperatures.
To adjust, we tighten the screws for the quantity and quality of the mixture until it stops, but do not tighten it with force. Next, unscrew each of them a couple of turns back. We start the engine and begin to alternately reduce the quality and quantity of the supplied fuel until a stable engine operation mode is established. It will be heard that the engine runs smoothly without excessive "tear" or rotation occurs calmly on a non-lean mixture.
The correct speed for the "classic" VAZ is 800-900 rpm. It is adjusted using the “quantity” screw. With the “quality” screw, we set the level of CO concentration in the range of 0.5-1.2%.
Adjusting the work of carburetor rods
The adjustment of the rods begins with the removal of the cover from the air filter, which blocks access for work. Using a caliper, we check the tabular factory value between the rod ends. It should be 80 mm. To adjust the length of the rod, loosen its clamp with a screwdriver. We loosen the lock nut with a key of 8 and change the length by rotating the tip.
After that, we fix all the fasteners and fix the rod in its nest. By pressing the "gas" pedal, we reveal the degree of opening of the throttle valve. If it does not turn completely, then it is necessary to eliminate the identified power reserve. To do this, you will need to reduce the length of the traction. We take it out, and with the help of a lock nut we reduce the dimensions. We put the traction in its place and conduct a test with pressing the accelerator pedal again.
Rod adjustment
It must also be taken into account that in the normal state the damper must be completely closed. You can increase the length of the pull by loosening the cable.
Screen filter check
Before this operation, it is necessary to pump fuel into the float chamber. This will make it possible to evaluate the closing of the shut-off valve. Next, you need to move the cover on the filter and dismantle the valve. It is advisable to clean it in a bath with a solvent, and then dry it with a compressor.
Incorrect engine operation, frequent failures and unreasonable loss of power can be blamed on poor fuel supply. This is also noticeable when the engine responds inadequately to pressing the gas pedal.
At the same time, the tightness of the locking needle can be checked. The operation is carried out with a medical rubber bulb. The pressure it produces is comparable to the level that the fuel pump produces. When reinstalling the carburetor cap, the float should be in the up position. During this operation, resistance should be heard. At the same time, you need to listen to air leaks, if they exist, you will need to change the needle.
Conclusion
Almost all carburetor settings can be done at home with a minimum set of tools. During disassembly of the unit, it is necessary to remember which parts, where they were, in order to return them back. Do not clean jets with steel needles. You can quickly dry the carburetor after washing with compressed air from a compressor or a car pump. It is recommended to blow the jets from contamination in the same way.
Caster angle (caster) - the angle between the axis of rotation of the wheel and the vertical in the side view. It is considered positive if the axis is tilted back relative to the direction of motion.
Camber - the inclination of the wheel plane to the perpendicular, restored to the plane of the road. If the upper part of the wheel is tilted outward of the car, then the camber angle is positive, and if inward, then it is negative.
Convergence - the angle between the longitudinal axis of the car and the plane passing through the center of the tire of the steered wheel. Convergence is considered positive if the planes of rotation of the wheels intersect in front of the car, and negative if, on the contrary, they intersect somewhere behind.
The following are experiments that allow you to understand how wheel adjustments affect the behavior of the car.
The Samara VAZ-2114 was chosen for the tests - most modern foreign cars do not burden the owner with a range and choice of adjustments. There, all the parameters are set by the manufacturer and it is quite difficult to influence them without constructive alterations.
The new car has an unexpectedly light steering and slurred behavior on the road. The camber angles are within the tolerance range, with the exception of the longitudinal angle of inclination of the axis of rotation of the left wheel (caster). With regard to the front suspension of a domestic front-wheel drive car, setting angles always begins with adjusting the caster. It is this parameter, on the one hand, that determines the rest, and on the other hand, it has a lesser effect on tire wear and other nuances associated with the car's rolling. Moreover, this operation is the most time-consuming - I think that is why it is “forgotten” at the plant. Only then, having dealt with the longitudinal angles, a competent master begins to adjust the camber, and then the toe-in.
Option 1
The master maximally shifts the angles of the longitudinal inclination of the racks, taking them to the “minus”. We kind of move the front wheels back to the mudguards of the wheel wells. A situation that is quite common on old and heavily “left” cars or after installing spacers that raise the rear of the car. The result: light steering, fast responses to its slightest deviations. However, "Samara" has become overly nervous and fidgety, which is especially noticeable at speeds after 80-90 km / h and above. The car has unstable responses when entering a turn (not necessarily fast), strives to take risks to the side, requiring the driver to constantly steer. The situation becomes more complicated when performing the “rearrangement” maneuver.
Option 2
The "correct" position of the racks (tilted to the "plus"), set to "zero" and the angles of convergence and collapse. The steering wheel has become elastic and informative, and a little more "heavy". The car drives clearly, clearly and correctly. The fidgetiness, slurred relationships and trajectory yaws have disappeared. At the "rearrangement" VAZ easily outstripped the previous version.
Option 3
Overly "positive" collapse. It is undesirable to change it without correcting the convergence, therefore, a positive convergence is also introduced.
Again, the steering wheel became "lighter", the responses at the entrance to the turn became lazier, the lateral buildup of the body increased. But there are no catastrophic deteriorations in character. However, when modeling an extreme situation, the "rudder feeling" is lost. With the advent of slips, unexpectedly early, it becomes more difficult to get into a given corridor on the "rearrangement" and the car starts to slide too early. In fast corners, the strongest slippage of the front axle dominates.
Option 4
A variant with sporting ambitions: everything is in the "minus", except for the caster. A car with such settings turns more confidently and faster, as well as the “rearrangement” maneuver. Hence the best result.
So, there are many simple and very effective ways to change the character of the car without resorting to costly replacements of components and parts. The main thing is not to neglect the adjustments - they often turn out to be very important.
Which of the options to give preference? For most, the second will be acceptable. It is most logical for everyday driving, both with partial and full load. It is only necessary to take into account that by increasing the longitudinal inclination of the rack, you not only improve the behavior of the car, but also increase the stabilizing (return) force on the steering wheel.
The last, most “fastest” setting option is more suitable for the near-sports audience who loves to improvise with the car. Giving preference to these adjustments, it must be borne in mind that with increasing load, the values \u200b\u200bof the toe and camber angles will increase and may go beyond the permissible limits.
The caster angle is one of the most important parameters when setting up a car. The behavior of the car on the road depends on it. For ordinary motorists, it is not so important to set the exact angle, it is enough for them to have an electric booster or power steering.
For racers in sports cars, the situation is different, you have to rack your brains over this issue. There are many theories about how the caster angle affects how the car behaves. Sometimes it is very difficult to choose the optimal adjustment angle for the desired stability of your car.
What is caster
The caster angle is the deviation of the angle of the longitudinal axis from the vertical. The function is to stabilize the rectilinear movement of the car. It turns out a self-centering system, which in different conditions can affect the turn of the car and the steering wheel in different ways. Self-centering directly depends on the steering of the wheels. The larger the caster angle, the better the centering, but the wider the turning radius of the car.
It is important to set the angle correctly, if your path lies along a high-speed highway, without a large number of sharp turns and bumps, then you should set a large angle, but if you are going to drive along a serpentine, then the angle should be minimal. The wheel caster makes the car go straight when the steering wheel is released. The greater the deviation from the vertical axis, the more stable the vehicle on the road. It also prevents the car from tilting and tipping over.
Properly set camber toe ensures maximum tire contact with the road. But when you turn the steering wheel, the tire deforms under the action of lateral force. The caster tilts the wheels in the direction the steering wheel is turned, thereby increasing the efficiency of the camber. The largest area of contact between the tire and the contact patch is achieved.
Caster happens:
- Positive - the axis of rotation is tilted back.
- Zero - the axis of rotation coincides with the vertical.
- Negative - the axis of rotation is deflected forward.
How does the caster angle affect the handling of the car?
Imagine the situation, you are driving on smooth asphalt, there is a turn ahead and at a speed of 40 km / h the car makes a maneuver. The car begins to describe an arc of rotation, when suddenly the front axle begins to slip, you loosen the steering angle, but the car still takes out to the outer part of the turn and there is nothing left to do but increase or decrease speed, catching the grip of the tires with the road. This happened due to understeer. Front or rear steering, depending on what your main drive, simply did not catch traction. There can be many reasons:
- wheel axle width;
- tire pressure;
- no high friction differential;
- incorrectly distributed ballast;
- longitudinal inclination of the axis of rotation (caster).
All this affects the behavior of the car when turning. The slightest change in one of the parameters can significantly affect the handling of the entire vehicle. The manufacturer tries to find a compromise between the value of all parameters of the car. And often sacrifice maneuverability for the sake of comfort. Therefore, a small angle of Ackermann and caster is set. Considering that everyday use does not require the characteristics of a racing car that reacts to the slightest corner of the turn.
Slight caster deviation
On cars, I set a positive deflection angle within 1-2˚, which provides a sharper steering angle. The suspension catches bumps and bumps better, the ride becomes softer. However, when exiting a turn, the load will be transferred to the rear axle and the front wheels, from which the load has gone, hold the road worse. The wheel self-centers worse, you have to bring it yourself.
tilted caster
By increasing the caster angle to 5-6˚, the steering wheel becomes heavier, information content, controllability, feedback increase and traction improves when exiting a turn. But the steering of the wheels at the beginning of the turn worsens, the axle deviates less to the side. Self-centering improves as the wheels resist centrifugal force and try to return to their original position.
Caster adjustment
Caster is set by the manufacturer. It is determined by the design and geometry of the parts. If you had a deviation of it, then most likely there was a blow in which it was displaced. And you need to go to the service for diagnostics and replacement of deformed parts. In 98% of cases, caster adjustment is not provided, which may be a revelation for some. Caster only complements the behavioral characteristics of each individual car, the angles are individual.
Mercedes-Benz can serve as an example, they have a caster angle of +10-12˚, while they have excellent maneuverability, handling and stability on the road. This effect is achieved by changing the collapse. With such a slope, the camber angles will be greater than with a slope of 1-2 degrees, and the car will not lose maneuverability and remain stable. So the goal was achieved in a non-standard way.
The Ford Focus 2 C-class car is equipped with high-level optics from the factory. Depending on the configuration, a reflector with a halogen lamp or a xenon lens with an automatic washer is responsible for external lighting. Adjusting the headlights of the Ford Focus 2 is rarely required due to the high-quality internal mechanism. But due to falling into a large hole in the road or a small accident, the lens or reflective element may be displaced. In this case, it is better to make an adjustment.
How to determine that an optical adjustment is required?
On the Ford Focus 2 it is required in case of insufficient illumination of the roadway at night. Visual signs of a misconfigured headlight:
In the event of the above problems, you need to check the position of the electric headlight range control knob in the cabin. If necessary, return the regulator to position "0" and check if the problem has not been eliminated. Adjusting the headlights of the Ford Focus 2 (restyling and dorestyling) can go astray by accidentally pressing the headlight beam adjustment key from the passenger compartment. If the corrector settings are correct, then the headlight mechanism will need to be adjusted.
What is the effect of the adjustment? Is it difficult to adjust the optics yourself?
The correct setting of the light beam mainly affects safety. The viewing range depends on this parameter not only in the dark, but also in rain, fog, snow. Incorrect adjustment can lead to serious consequences, for example, if the driver does not notice a broken car on the highway or severely dazzles the oncoming car owner.
Adjusting the Ford Focus 2 headlights will not take much time. But you need some preparation of the car before work:
- Vehicle headlights must be clean.
- You should check the pressure in the wheels and pump up to the parameters stated on the car rack or door trim.
- Stock up on the necessary tools: tape measure, screwdriver, torx star, crayon or marker.
- Pre-find a flat area with a building or wall.
After simple preparations, you can start setting up. Adjusting the Ford Focus 2 headlights will take 15-20 minutes in time.
How do you adjust your headlights?
To properly configure the head optics, you need to follow the steps:
- Put the car headlights against the wall at a distance of 3 meters.
- Turn on the dipped headlights and measure the height of the beam boundary from the ground.
- The border of the light line should be 35 millimeters less than the height from the ground to the car bulb.
- When measuring, the maximum distance of the center of the beam from both headlights should be equal to 1270 millimeters.
- For ease of adjustment, small lines should be marked on the wall with a chalk or a marker, on which light should fall.
- Open the hood. Find the adjusting screws on top of the headlight, they are made for a regular screwdriver or torx star.
- The screw on the side edge of the headlight of the car is responsible for turning left and right.
- The screw, located in the center of the headlight, is responsible for tilting up and down.
- Use the screws to adjust the beam of light along the pre-marked lines on the wall.
Adjusting the Ford Focus 2 headlights does not require much time and special knowledge. After the work has been done, close the hood and drive through poorly lit places. After making sure that the lighting devices work correctly, the setting can be considered completed.
Adjust by yourself or in the service
Adjusting the Ford Focus 2 headlights at a service center can cost 1,000-2,000 rubles. However, the check is much cheaper - 200-300 rubles. To save money, you can independently carry out tuning work, and in the service, additionally check the corners of the head light on a special stand.
Despite the simplicity, adjusting the light of the head optics is a very important and responsible job, on which the safety of not only the car owner, but also other vehicles depends. That is why, after doing the settings yourself, you still need to call at a service station and do an express check.
The present article discusses the effect of drive adjustment on the operation of the brake force regulator (VAZ-2108-351205211) of front-wheel drive VAZ vehicles. A drive that has been properly adjusted at the factory is subjected to vibration loads during operation, leading to a change in the mounting point of the drive. For the study, the brake force regulator and its mechanical drive, which have no operating time, were taken. The output parameters were taken on the stand - the brake fluid pressure created at the outlet openings of the brake force regulator, at different positions of the drive attachment point and two load modes, simulating the equipped and full weight of the car. Based on the data obtained, the performance characteristics of the brake force regulator were built. Based on the results of the analysis, conclusions were drawn about the influence of the position of the attachment point of the brake force regulator drive on its performance. To confirm the obtained laboratory data, the mechanical drives of the brake force regulator of the operated VAZ vehicles were investigated. When analyzing the obtained data, the maximum operating time of the fastening elements of the mechanical drive of the brake force regulator was determined, on the basis of which recommendations were formulated on the technical impact during maintenance.
mechanical drive of the brake force regulator.
brake force regulator
brake circuits
working brake system
1. VAZ-2110i, -2111i, -2112i. Instructions for use, maintenance and repair. - M.: Publishing House Tretiy Rim, 2008. - 192 p.;
2. Utility model patent No. 130936 “Test for determining the static characteristic of the brake force regulator” / D.N. Smirnov, S.V. Kurochkin, V.A. Nemkov // Patentee of VlSU, registered on August 10, 2013;
3. Smirnov D.N. Study of the wear of structural elements of the brake force regulator // Electronic scientific journal "Modern problems of science and education". – 2013. -№2. SSN-1817-6321 / http://www..
4. Smirnov D.N., Kirillov A.G. Investigation of the efficiency of the brake force regulator drive // Actual problems of vehicle operation: materials of the XIV International scientific and practical conference / ed. A.G. Kirillov. - Vladimir: VlGU, 2011. - 334 p. ISBN 978-5-9984-0237-1;
5. Smirnov D.N., Nemkov V.A., Mayunov E.V. Stand for determining the static characteristics of the brake force regulator // Actual problems of vehicle operation: materials of the XIV International scientific and practical conference / ed. A.G. Kirillov. - Vladimir: VlGU, 2011. - 334 p. ISBN 978-5-9984-0237-1.
Introduction. The studies of the operation of the brake force regulator (RTS) conducted by the authors under operating conditions made it possible to establish that its performance is affected by a change in the geometric parameters of the RTS elements. During operation, the mating surfaces of RTS structural elements are subjected to mechanical and corrosion-mechanical wear. The greater the wear of the elements, the higher the likelihood of failure of the regulator. The performance of the RTS is also affected by its drive.
Materials and research methods. In the design of the RTS drive, there are four interfaces of structural elements, which during operation are characterized by characteristic defects or wear, leading to incorrect operation of the system:
- incorrect position of the torsion bar and the regulator drive lever;
- wear of the pin of the two-arm bracket of the RTS drive lever;
- incorrect adjustment of the PTC drive mount (item 4, Fig. 1);
- wear of the differential piston rod head.
Defects in all four conjugations are formed in parallel, but they can appear either separately from each other or simultaneously. The most common defect is incorrect drive adjustment.
Rice. 1. Brake force regulator with drive: 1 - lever spring; 2 - pins; 3 - two-arm bracket of the RTS drive lever; 4 - drive mount; 5 - bracket for fastening the regulator to the car body; 6 - elastic lever (torsion) of the RTS drive; 7 - RTS; 8 - regulator drive lever; A, D - RTS inlets; B, C - RTS outlets
Incorrect drive adjustment occurs when shifting to the left or right relative to the RTS of the two-arm bracket of the regulator drive lever 3 (Fig. 1), which has an oval hole at the attachment point 4 (the length of the major axis is 20 mm). This shift may be the result of operation (loose fastening due to vibration load or constant overloading of the vehicle) or the intervention of incompetent persons.
The recommended adjustment of the drive is ensured by observing the gap between the lower part of the lever 8 of the regulator drive and the spring 1 of the lever. This gap, according to the manufacturer's recommendations, should be within ∆ = 2 ... 2.1 mm with the curb weight of the car.
Results of the study and their discussion. Consider the performance characteristics of the RTS with various drive adjustments. For the study, the regulator and its drive were taken, which were not used on the car. The choice of a new regulator is based on the absence of wear of the RTS elements and its drive, which makes it possible to obtain the standard characteristics of the RTS.
To obtain the performance characteristics of the RTS, a stand was used to determine the static characteristic of the brake force regulator.
On fig. 2, a shows the performance characteristics of the RTS when simulating the equipped state of the car in three positions of the drive adjustment.
With the recommended adjustment of the drive (lines 1, 2, Fig. 2, a), the brake fluid pressure is limited at p0xav = 3.04 MPa, which is within acceptable limits when compared with the factory characteristics (lines vg and ng, Fig. 2, A). Further, a gradual increase in pressure continues due to the throttling of the liquid inside the RTS. As a result, at the brake fluid pressure at inlets A, DRTS p0 = 9.81 MPa, at outlet B - p1 = 4.61 MPa, at outlet C - p2 = 4.90 MPa, which also fits into the permissible corridor set by the factory - manufacturer (lines vg and ng, Fig. 2, a). The difference between the brake fluid pressure outputs p1 and p2 is ∆p =0.29 MPa, which corresponds to the permissible limits of the factory specification.
When adjusting the drive in the extreme left position (lines 3, 4, Fig. 2, a), there is no complete operation of the RTS, but there is a moment of its beginning to operate, which is observed at p0xleft = 4.12 MPa. This fact is explained by the fact that the drive fixed in the extreme left position acts on the piston rod with a large force Pp, which is higher than the resulting force on the piston head at the maximum value p0max (as measurements showed p0max>>9.81 MPa). Ultimately, at the brake fluid pressure at inlets A, DPTC p0 = 9.81 MPa, pressure p1 = 6.77 MPa will be created at outlet B and at outlet C - p2 = 7.45 MPa. The difference between the brake fluid pressure output values is ∆p = 0.69 MPa, which exceeds the allowable value by 0.29 MPa.
Driving under these conditions is dangerous for two reasons:
§ the pressure of the brake fluid in the brake mechanisms of the rear axle goes beyond the upper limit of the corridor of recommended values, which will lead to the primary blocking of the wheels of the rear axle in case of emergency braking at all values of φ;
§ The uneven braking force of the rear axle, caused by the pressure difference, can lead to loss of vehicle stability during emergency braking, regardless of the condition of the surface.
Rice. 2. Operating characteristics of the RTS with different fixation of the drive: a) - with the curb weight of the car; b) - with the total mass of the car; p0 - the value of the brake fluid pressure at the inlets of the RTS, MPa; p1, p2 - the value of the pressure of the brake fluid at the output holes of the RTS; 1, 2 - correct fixation of the drive; 3, 4 - fixation of the drive in the extreme left position; 5, 6 - fixation of the drive in the extreme right position; 1, 3, 6 - change in brake fluid pressure on the brake mechanism of the rear left wheel of the car; 2, 4, 5 - change in brake fluid pressure on the brake mechanism of the rear right wheel of the car; vg, ng - upper and lower limits of permissible values of operating characteristics; nom - nominal value of the operating characteristic; p0xav, p0xleft - brake fluid pressure at which the RTS is activated, with the drive correctly fixed and fixed in the leftmost position, respectively
Adjustment of the drive in the extreme right position creates a gap ∆ = 6…6.1 mm between the lower part of the lever 8 of the regulator drive (Fig. 1) and the spring 1 of the lever. This gap value makes the mechanical drive of the RTS useless with the curb weight of the car, because. the drive does not provide force on the head of the piston rod, which is shown by the operating characteristic (lines 5, 6, Fig. 2, a). The PTC trigger point is missing for output C and is at zero for output B. There is no increase in brake fluid pressure p2 at outlet C, because the PTC plug valve is in the closed position. With an inlet pressure (holes A, D, Fig. 1) p0 = 9.81 MPa, the brake fluid pressure at outlet B will be limited to p1 = 2.45 MPa. The difference between the brake fluid pressure outputs p1 and p2 exceeds the permissible value ∆p = 2.06 MPa set by the manufacturer.
Operation of the vehicle when the PTC drive is adjusted in the extreme right position is dangerous for the same reasons as when adjusted in the extreme left position.
On fig. 2, b shows the performance characteristics of the RTS in three positions of the drive locking when simulating the full load of the car.
With the recommended drive adjustment position (lines 1, 2, Fig. 2, b), the brake fluid pressure characteristics at the RTS outlets are almost linear. The difference between the outlet pressures p1 and p2 of the brake fluid is ∆p = 0.39 MPa (for example, with an inlet pressure p0 = 2.94 MPa) - within acceptable limits. There is no pressure limitation at outlets B and C, because when simulating a full vehicle load, the mechanical drive acts on the piston rod with a force that is higher than the resulting force on the head of the differential piston rod at the maximum value p0max.
When the drive is adjusted in the extreme left position, the performance characteristics of the RTS have the same form (lines 3, 4, Fig. 2, b) as the performance characteristics with the recommended drive adjustment. The brake fluid pressure is not limited at the PTC outlets. As a result, at the input values of brake fluid pressure p0 = 9.81 MPa, the outputs of the RTS will be p1 = 9.81 MPa, p2 = 9.61 MPa. Outlet pressure difference ∆p = 0.20 MPa within acceptable limits.
When adjusting the drive in the extreme right position (lines 5, 6, Fig. 2, b), the performance characteristics have the form of performance characteristics obtained by simulating the equipped state of the car and the recommended drive adjustment (lines 1, 2, Fig. 2, a). But there is one significant difference: the brake fluid pressure is limited very early, and the actuation point can lie in the interval p0x = 0 ... 0.39 MPa. This will lead to a significant reduction in the life of the pads and tires of the front wheels, because. at full vehicle load, the front brakes will constantly be overloaded with increasing braking force.
To collect statistical data related to the change in the adjustment of the RTS drive, we studied cars that are in operation in the central federal district of the Russian Federation on ordinary type roads of category II, III, IV and V. The cars had different service life, ranging from 3 to 70 thousand km 55 vehicles with the VAZ-2108-351205211 marking in the RTS brake drive were subjected to the study.
Analyzing the collected statistical data on the reliability of the mechanical drive and the probability of its failure due to a change in kinematics, a graph of the dependence of the change in the adjustment position ∆S of the drive fastening on the operating time of the drive RTS was obtained (Fig. 3).
Rice. Fig. 3. Graph of the dependence of the shift of the mechanical drive mount on the operating time: ∆S - the amount of change in the adjustment position of the drive mount, mm; L is the operating time of the RTS drive, thousand km; X - shift start point; Y - point of critical shift value; 1 - line characterizing the maximum allowable displacement of the RTS drive mount; dependence equation: ∆S = 0.0021L2 - 0.0675L + 0.2128
In interval 1 (Fig. 3) of operating time (29.1% of the studied vehicles), the cause of failures is a violation of manufacturing and assembly technology. There is no change in the adjustment position ∆S of the drive mount in interval 1.
In interval 2 (Fig. 3) of operating time L from 29.400 ± 0.220 to 51.143 ± 0.220 thousand km (41.8% of the sample), a change in the adjustment position ∆S of the drive mount begins to appear towards the extreme right position. On the run L = 51.143 ± 0.220 thousand km, there is a change in the position of the adjustment ∆S = 2.25 mm of the drive mount, while the gap between the lower part of the lever 8 (Fig. 1) of the regulator drive and the spring 1 of the lever ∆ = 3.5 ... 3.6 mm. With such a gap, the RTS plug valve, which is responsible for limiting the brake fluid pressure in the drive to the rear right working cylinder and having a stroke of 1.5 mm, will be closed with the vehicle curb weight. As a result, a difference in braking forces will occur on the wheels of the rear axle, which will lead to a loss of vehicle stability during braking.
On fig. 4 shows a direct dependence of the gap ∆ on the change in the position of the adjustment ∆S of the fastening of the PTC drive, and in fig. 5 - dependence of the dynamic conversion factor Wd RTS on the change in the adjustment position ∆S of the fastening of the RTS drive. The value of the maximum allowable change in the adjustment position ∆S of the PTC actuator mounting to the right side, determined in two ways, has one value ∆S = 2.25 mm.
With further operation of the car (more than L = 51.143 ± 0.220 thousand km, interval 3), the probability of RTS failure increases due to the lack of force Pp from the drive.
Rice. Fig. 4. Dependence of the gap ∆ between the lower part of the regulator drive lever and the lever spring on the change in the mounting position ∆S of the PTC drive; dependency equation: ∆ = 0.6667∆S + 2.1
Rice. Fig. 5. Dependence of the dynamic conversion factor Wd RTS on the change in the mounting position ∆S of the RTS drive: 1, 2, 3 - lower limit, nominal value and upper limit of the dynamic conversion factor RTS, respectively; 4 - change in the dynamic conversion factor from the extreme left fixation of the drive to the extreme right; A, B - the maximum allowable values of the shift of the RTS drive to the left and right side, respectively
In the course of the research, cases were observed that did not correspond to a natural operational change in the position of the RTS drive mount (5.5% of the vehicles under study): ; 2) on a car with a mileage L = 58.318 thousand km from the beginning of operation, the change in the position of the drive mount was towards the extreme right position by 6 mm; 3) on a car with L = 60.762 thousand km of operating time, the change in the drive mounting position was 1 mm towards the extreme right position of the RTS drive fixation.
Based on the results of the study, it can be recommended to include the following types of work on the RTS drive into the regulatory technical impacts:
- when carrying out maintenance (TO) at a mileage of 30 thousand km, pay increased attention to the condition of the RTS and its mechanical drive. Check the change in the drive mounting position, correct its required position by measuring the gap ∆ between the lower part of the lever 8 (Fig. 1) of the regulator drive and the spring 1 of the lever;
- when carrying out maintenance on a run of 45 thousand km, replace the drive mounting elements: M8 × 50 bolt for mounting the drive 4 (Fig. 1), bracket 5 for mounting the regulator to the body. Set the required gap ∆ between the lower part of the lever 8 (Fig. 1) of the regulator drive and the spring 7 of the lever;
- at each subsequent maintenance, with a frequency of 15 thousand km, carry out maintenance work on the RTS mechanical drive described in paragraph 1, and with a frequency of 45 thousand km - the work described in paragraph 2.
Conclusions. Thus, the adjustment position of the drive has a significant impact on the work processes of the PTC. Studies have shown that when the car is fully loaded, changing the adjustment position of the PTS drive affects active safety to a lesser extent than with the curb weight. With a curb weight, it is dangerous to operate the car when the drive adjustment position is changed from the recommended one, because. there is a primary blocking of the wheels of the rear axle of the car, and further operation can lead to a traffic accident. When examining a sample of cars, it was found that changes in the RTS drive settings begin to occur at L = 29.400 ± 0.220 thousand km of operation. In most cases (70.9% of the sample), the change in the position of the drive mount occurs towards the extreme right position. Therefore, it is necessary to carry out a set of measures aimed at servicing the RTS mechanical drive when the vehicle reaches a mileage of 30 thousand km, and when servicing at a mileage of 45 thousand km, it is necessary to replace the fastening elements of the RTS mechanical drive.
Reviewers:
Gots A.N., Doctor of Technical Sciences, Professor of the Department "Heat Engines and Power Plants" of the Federal State Budgetary Educational Institution of Higher Professional Education "Alexander Grigorievich and Nikolai Grigorievich Stoletov Vladimir State University" (VlGU), Vladimir.
Kulchitsky A.R., Doctor of Technical Sciences, Professor, Chief Specialist of LLC “Plant of Innovative Products”, Vladimir.
Bibliographic link
Smirnov D.N., Kirillov A.G., Nuzhdin R.V. INFLUENCE OF ADJUSTING THE DRIVE ON THE OPERATION OF THE REGULATOR OF BRAKING FORCES // Modern problems of science and education. - 2013. - No. 6.;URL: http://science-education.ru/ru/article/view?id=11523 (date of access: 01.02.2020). We bring to your attention the journals published by the publishing house "Academy of Natural History"
