Selecting the correct camshaft should start with two important decisions:
First, let's check how we define the operating RPM range and how the choice of camshaft is determined by that choice. The maximum engine speed is usually easy to isolate as it directly affects reliability, particularly when the main parts of the block are common.
Maximum engine speed and reliability for most engines
| Maximum engine speed | Estimated working conditions | Life Expectancy with Corresponding Parts |
| 4500/5000 | Normal movement | More than 160,000 km |
| 5500/6000 | "Soft" forcing | More than 160,000 km |
| 6000/6500 | Approximately 120,000-160,000 km | |
| 6200/7000 | Forcing for everyday driving / "soft" racing | About 80,000 km |
| 6500/7500 | Very “hard” street driving or racing from “soft” to “hard” | Less than 80,000 km in street driving |
| 7000/8000 | Only "hard" races | Approximately 50-100 rides |
Keep in mind that these guidelines are general. One engine can hold up much better than another in any category. How often the engine accelerates to maximum rpm is also very important. However, as general rule you need to be guided by the following: the maximum engine speed should be below 6500 rpm if you are creating a forced engine for everyday driving, and you need it reliable work... These engine speeds are typical for the limits of most parts and can be obtained with medium force valve springs. Therefore, if reliability is the main goal, then the maximum speed of 6000/6500 rpm will be a practical limit. While deciding the maximum RPM required can be a relatively straightforward process, based in principle on reliability (and perhaps cost), an inexperienced engine designer may find it much more difficult and dangerous to determine the engine's operating speed range. Valve lift, cycle times and cam profile camshaft will determine the power range, and some inexperienced mechanics may be tempted to select the "largest" possible camshaft in an attempt to increase maximum power engine. However, it is important to know that maximum power is only needed for a short time, when the engine reaches maximum rpm. The power required from most high-powered engines is well below the maximum power and RPM; in fact, a typical boosted engine may "see" full opening throttle just a few minutes or seconds in a full day of work. However, some inexperienced engine builders ignore this obvious fact and choose the camshaft more by intuition than guided? If you suppress your desires and make careful choices based on real facts and possibilities, you can create an engine capable of delivering impressive power. Always keep in mind that the camshaft is pretty much a compromise piece. After a certain moment, all increases are given at the cost of power for low revs, loss of throttle response, efficiency, etc. If your goal is to increase the number of horse powerthen make modifications first that add maximum power by improving intake efficiency, as these changes have less effect on power at low rpm. For example, optimize the flow in the cylinder head and in the exhaust system, reduce the flow resistance in the intake manifold and in the carburetor, then install the camshaft in addition to all of the above "kit". If you use these tricks carefully, the engine will deliver the broader power curve possible for your investment of time and money.
In conclusion, if you have a car with automatic transmission, then you need to be conservative when choosing the valve timing of your camshaft. Excessive valve opening times will limit engine power and torque at low rpm, which are essential elements in ensuring good acceleration and pulling away. If your vehicle's torque converter (converter) stops at 1500 rpm (typical for many standard transmissions), a camshaft that delivers good torque, although not necessarily maximum power, at 1500 rpm will accelerate well. You may be tempted to use a torque converter with high stop rpm and a long opening camshaft in an effort to achieve better result... However, if you use one of these torque converters during normal driving, their efficiency at low revs will be very poor. Fuel efficiency will suffer quite a lot. For a car in everyday use, there are better ways to improve acceleration from low revs.
Let's summarize the main elements of camshaft selection. First, for everyday driving, the maximum engine speed must be maintained at no more than 6500 rpm. RPMs above this limit will significantly reduce engine life and increase component costs. While a "conventional" engine may benefit from as much valve lift as possible, too much valve lift will reduce engine reliability. For all high-lift camshafts, bronze valve guides are essential to ensure long bushing life, but for valve lift of 14.0 mm or more, even bronze guide bushings cannot reduce wear to a level acceptable for normal applications.
The longer the valves are held open, especially inlet valve, the more maximum power the engine will deliver. However, due to the variable nature of the camshaft timing, if the duration of valve opening or valve overlap goes beyond a certain value, all the additional maximum power will be gained at the cost of quality at low rpm. Camshafts with an intake stroke of up to 2700, measured at zero valve lift, are a good replacement for standard camshafts. For high-performance engines, the upper limit for intake stroke times over 2950 is a pure racing engine's accessory.
Valve overlap causes some torque loss at low rpm, however, this loss is reduced when overlap is carefully selected for a particular application - from about 400 for standard engine camshafts to 750 or more for special applications.
Valve opening times, valve overlap, valve timing and cam center angles are all related. It is not possible to set each of these characteristics independently on engines with one camshaft.
Fortunately, most camshaft machinists have spent many years creating cam profiles for power and reliability, so they can offer a camshaft that suits your needs well. However, do not blindly perceive what the masters are offering you; you now have the information you need to competently discuss the specifics of the camshafts with their manufacturers.
After all, the camshaft is one part of the intake system. It should be matched with the cylinder head, intake manifold and exhaust system. Volume intake manifold and the size of the exhaust manifold pipes must be sized to fit the engine power curve. In addition to this, carburetor air flow rate, number of chambers, type of secondary chamber activation, etc. also have a noticeable effect on power.
DIY chainsaw carburetor setting
For an independent carburetor option, you must familiarize yourself with its device and understand the procedure for the work that is carried out to adjust the parts responsible for the correct functioning component parts device and nearby parts.
It is necessary to carefully handle the items for the system option, and also to determine whether the set characteristics correspond to very permissible values.
About the carburetor device
The carburetor serves to mix the combustible consistency with air, while observing the proportions established in advance. If clear doses are not followed, the proper operation of the motor is at risk. When a huge amount of air enters during mixing of a component, and there is not enough fuel, then such a mixture is considered "poor".
Over-saturation should not be allowed, because with a large amount of fuel compared to air, malfunctions or engine wear are also likely. Adjustment of the carburetor is needed not only before the initial introduction, but also when any differences in its operation are revealed. Before starting work with the chainsaw, do not forget to run it in.
Components of the carburetor
The carburetor design contains standard set parts, but may vary slightly depending on the manufacturer. Components:
- The foundation... It is a special tube that visually resembles an aerodynamic structure. Air passes through it. In the transverse direction in the middle of the pipe there is a damper. Its position can be changed. The more it is pushed into the passage, the less air enters the engine.
- Diffuser... This is the tapered part of the tube. With its help, the air flow rate increases exactly in the segment from which the fuel comes out.
- Channels for fuel supply. Fuel mixture contained in the float chamber, then passes into the nozzle, from which it flows into the sprayer.
- Float chamber... It is a separate structural element, reminiscent of the shape of a tank. Designed to constantly maintain the optimal level of the fuel fluid in front of the inlet to the air channel.
Not sure which chainsaw to choose? Read our article.
Looking for models that are cheaper, but reliable and time-tested? Pay attention to Russian-made chainsaws.
Alternatively, research foreign chainsaw manufacturers such as Stihl.
What you need to have to set up
Every carburetor owner must have necessary tools to adjust this system. There are three adjusting screws located on the body of the device. They have their own markings:
- L - screw for low rpm correction.
- H - screw for high speed adjustment.
- T - regulates idle move, in most cases it is used for experiments.
Chainsaw air filter
Before adjusting the carburetor, you need to prepare the device:
- The engine warms up, that is, it starts about 10 minutes before the repair, and turns off when you start work (see how to start the chainsaw).
- The air filter is checked and washed.
- The chain is stopped by turning the screw T as far as it will go (see chain oil).
To carry out a safe repair, you need to prepare a flat surface where you can carefully position the device, and turn the chain in the opposite direction. We need a tachometer. It determines the presence of a malfunction in the carburetor. When the screws are turning, the sound should be perfect and absolutely smooth. If squealing notes are noticed, then the mixture is oversaturated.
Setting instructions
Carburetor adjustment is divided into two main steps. The first is called basic. It is performed with the engine running. The second is performed when the engine is warm.
To carry out the carburetor tuning procedure successfully, you need to read the operating instructions in advance specific model to identify additional features device settings.
First stage
The adjusting screws for the highest and lowest speed should be moved clockwise until the highest resistance is encountered. When the screws reach the stop, you need to translate them into back side and leave after passing 1.5 turns.
The main stage
Chainsaw STIHL 180 checking how many turns
In this video we will answer the question of how to tune or adjust the carburetor chainsaw do it yourself
Chainsaw STIHL 230 checking how many turns
Carburetor adjustment chainsaw DIY Champion 254. Initial carburetor adjustment shown
The engine turns on at medium speed and warms up like this for about 10 minutes. The screw responsible for adjusting the idle speed must move clockwise. It is released only when the engine comes into stable operation. It is necessary to check that the chain does not move during this process.
In idle mode, the engine may stall (the reason is here). In this case, immediately turn the adjusting screw clockwise until it stops. Sometimes the chain starts to move. In this case, turn the adjusting screw in the opposite direction.
Checking acceleration work
A little research needs to be done. The acceleration of the device is initiated. The serviceability of the engine should be assessed during the maximum revolutions. When the engine is functioning properly it means when you press the accelerator, the speed quickly increases to 15,000 rpm.
If this does not happen or the increase in speed is too slow, you must use the screw marked with the letter L. It turns counterclockwise. Moderate movements must be observed, since the turn cannot be more than 1/8 of a full circle.
Maximum number of revolutions
To limit this figure, you need to use a screw marked H. To increase the number of revolutions, turn it clockwise, and to decrease them in the opposite direction. The maximum frequency should not exceed 15000 rpm.
If you increase this indicator, the engine of the device will work for wear, which will lead to problems in the ignition system. When turning this screw, the ignition processes of the device must be taken into account. If the slightest glitches appear, then the maximum speed value must be reduced.
Final check at idle
Before this procedure, it is necessary to make a full adjustment of the components of the carburetor when operating at maximum speed. Next, you should check the functioning of the device in idle cold mode. When the correct parameters are reached during the adjustment, you can see the exact conformity of the carburetor design to the following criteria:
- When the idle cold mode is connected, the chain does not move.
Chainsaw accelerator
- When the accelerator is pressed even slightly, the engine revs up at an accelerated pace. With a gradual deepening of the pressure, it can be seen that the engine speed increases proportionally, reaching the maximum allowable values.
- When the engine is running, you can compare its sound to a four-stroke instrument.
If violations are noticed in the above parameters or the device was not adjusted in in full, you need to perform the main configuration step again. Sometimes actions are performed incorrectly. In this case, the device may fail due to the loss of the correct node settings. In this case, you will have to contact a specialist.
Dismantling the carburetor if it is necessary to check or repair components
Device different models carburetors are almost the same, so when working with them, you can use the standard scheme. All elements must be removed carefully, and then lay out in the order belowso that you can successfully place items in place at the end of the repair work.
Read:
Removing the top cover
- The top cover is removed. To do this, unscrew the 3 bolts holding it in a circle.
- The foam rubber is also removed, since it is the top part of filter that conducts air.
- The fuel hose is removed.
- The drive thrust is output directly to it.
- The cable end is disconnected.
- The petrol hose can be removed completely by pulling it off the fitting in a planned manner.
To finally prepare the carburetor for overhaul or replacement of the smallest parts, you need to carefully disconnect it from the main system... Sometimes further disassembly is required. Unscrew the components carefully and stack the fasteners in groups, as these small parts are easily lost.
Instruction for Chinese
To correctly configure the carburetor of a Chinese chainsaw, you must first remember the factory settings of the device, then turn on the engine. Subsequently, you will have to leave it to work for several hours in order to accurately set your own parameters. Sometimes the work is performed once after ten minutes of engine operation, but many Chinese-made models require special handling.
Chinese Chainsaw Model
Adjustment procedure:
- Activities start in idle mode... With the help of the adjusting screws, you need to achieve a systematic set of revolutions by the engine, therefore, you should first let it run at low speeds. The deviation from the norm is the movement of the chain along the tire. In this case, you need to adjust the extreme screws to the optimal position so that the chain remains stationary.
- Transition to average speed... Sometimes the engine will smoke. This defect can be eliminated by tightening the screw to supply a leaner fuel mixture.
In this case, the smoke will disappear, but the engine speed will increase. It is necessary to adjust the settings until the level is reached when, when you press the throttle, the engine smoothly picks up speed, no sudden jerks or interruptions are heard.
The characteristic of the turbojet engine in terms of the number of revolutions is curves that show the change in thrust and specific fuel consumption with a change in the number of revolutions (at a constant speed and flight altitude).
The characteristic for the number of revolutions is shown in Fig. 41.
When the thrust is changed in terms of revolutions, the following main engine operating modes are noted:
1. Low throttle or idle speed. This is the lowest RPM at which the engine runs stably and reliably. At the same time, stable combustion occurs in the combustion chambers, and the turbine power is quite sufficient to rotate the compressor and the units.
For a turbojet engine with a centrifugal compressor, the idle speed is 2400-2600 per minute. Engine idling thrust does not exceed 75-100 kg.
Idle speed specific consumption fuel is not a characteristic quantity; this is usually the hourly fuel consumption.
At idle speed, the turbine operates under severe temperature conditions and the oil supply to the bearings is very low. Therefore, the time of continuous operation on low gas is limited to 10 minutes.
2. Cruising mode - the engine operates at a speed at which the thrust is approximately 0.8 R MAX.
Figure: 41. Characteristics of the turbojet engine by the number of revolutions.
At these speeds, continuous and reliable engine operation is guaranteed for the specified service life (engine life).
The designer chooses the engine parameters (ε, T , Efficiency) in order to obtain the lowest specific fuel consumption during cruising.
The engine cruise mode is used for duration and range flights.
3. Nominal mode - the engine operates at speeds at which the thrust is approximately 0.9 R MAX.
Continuous work in this mode is allowed for no more than 1 hour.
In the nominal mode, climb and flights at higher speeds are performed.
According to the nominal mode, the thermal calculation of the engine and the calculation of parts for strength are performed.
4. Maximum (take-off) mode - the engine develops the maximum number of revolutions at which the maximum thrust P MAX is obtained - in this mode, continuous operation is allowed for no more than 6-10 minutes.
The maximum mode is used for takeoff, climb and short-term flight at maximum speed (when it is necessary to catch up with the enemy and attack him).
The characteristic for the number of revolutions is built under standard atmospheric conditions: air pressure Р О \u003d 760 mmrt. Art. and temperature T 0 \u003d 15 0 С.
Figure: 42. Change in specific fuel consumption by the number of revolutions.
With an increase in the engine speed (at constant altitude and flight speed), the second air consumption through the engine G SEC and the compression ratio of the compressor ε COMP. As a result, the engine thrust increases sharply and the specific fuel consumption decreases, the turbojet engine is more economical at high speeds. If the specific fuel consumption at maximum speed is taken as 100%, then the specific fuel consumption at idle speed will be 600-700% (Fig. 42). Therefore, it is necessary to reduce in every possible way the work of the turbojet engine at idle speed.
5. Fast and the furious. For engines with an afterburner, the characteristic also indicates the thrust, specific fuel consumption and the duration of the engine operation when the afterburner is turned on - the afterburner.
When the turbojet engine is started, the initial shaft spin up to idle speed is performed by an auxiliary starting motor.
Used as a starting engine: electric starters, starter-generators, turbojet starters.
Electric starter is an electric motor direct currentpowered by current from aircraft or airfield batteries during launch. Its power is about 15-20 liters. from.
On some turbojet engines, a starter-generator is installed, which, when started, works as an electric motor, and during engine operation, it works as a generator - it supplies current to the aircraft network.
The electric starter, or starter-generator, is included in automatic system launch, and its work is coordinated with the work of the launcher fuel system and ignition systems.
The turbojet starter is an auxiliary turbojet engine mounted on powerful turbojet engines.
A small electric motor starts the turbojet starter, which spins the main engine to idle speed and shuts down automatically.
Previously, when automatic washing machines were just coming into use, spinning the laundry in them was especially pleasing to the owners. No joke - technology freed them from such a tedious process. Then no one thought about the frequency with which the drum rotates. The machine still squeezed much better than a man. Now manufacturers are trying to make sure that the washing machine the linen could be hung up almost immediately in the closet. True, increasing the speed of rotation of the drum - the method by which they are trying to achieve this, in our opinion, is very doubtful. Let's try to figure out whether the washing machine needs "space" speeds?
Spinning in the washing machine: observe speed mode!
The final stage of washing - spinning has always been one of the most difficult stages of washing. As the saying goes, "the last fight is the most difficult one." Women, who in our country, as a rule, were engaged in washing, it was at this stage that they called for help from their husbands and children: one cannot squeeze a heavy duvet cover.
Fortunately, times have changed. Now, in fact, none of the family members is engaged in washing in the house. Preparing and sorting the laundry doesn't count. The process itself is at the mercy of automation - a modern washing machine has settled in our apartments.
You can talk for a long time about what programs and functions have washing machines of different price categories and manufacturers, how they differ from each other, or vice versa - similar. Sometimes, on specialized Internet forums or even just in the metro, disputes arise about which programs are needed for a washing machine, and which ones can be completely dispensed with. All debaters, however, agree on one thing - without spinning, an automatic washing machine would immediately lose its appeal.
Classes and spinning technology
Washing machines by spin class are divided into 7 categories, which are designated by the Latin letters A, B, C, D, E, F, G. The awarding of one category or another depends on the residual moisture of the laundry, which is measured as a percentage. It is determined simply - dry laundry is weighed before washing, and after it the wrung out (wet) is weighed. The dry weight is subtracted from the wet weight, and the resulting difference is divided again by the dry weight. The quotient is multiplied by 100 percent - the desired result is obtained.
The residual moisture of the laundry in spin class A should not exceed 45 percent. B-class allows residual moisture up to 54 percent, C - up to 63, and D - up to 72. Models that squeeze worse are now practically not found on sale.
I must also say that you should not be "afraid" of washing machines whose spin class is lower than A (by the way, most of them), the difference between classes A and B or even C - although it looks significant in percentage, in practice it is not so great. Of course, when spinning the C-class, it will take a little more time to dry the laundry, but the quality of the wash (what, in fact, the washing machine is needed for) will obviously not get worse.
But the spin class depends not only on the degree of residual moisture in the laundry. One of its criteria is also the number of revolutions that the drum of the washing machine can complete in a minute. The more of them, the higher the chances of the manufacturer to proudly announce that the spin class of their unit is A. In most models offered on the market today, the number of revolutions is 1000 - 1200 per minute. However, there are units that "accelerate" to 1600, 1800 and even 2000 rpm (for example, the Gorenje WA 65205 model).
Is this good or bad? Are such "cosmic" spin speeds needed, or will the usual, "earthly" ones be enough? To answer these questions, it is necessary, first, to understand how the spinning process itself actually occurs.
In principle, it is not difficult at all. After the end of rinsing, the used water is drained off using the pump. Then the spin itself begins. The number of revolutions of the drum gradually increases, water from the laundry, obeying the centrifugal force, enters the tank through the holes in the drum, while the pump periodically turns on and it is removed to the sewer. Maximum revolutions the engine (and hence the drum) reaches the end of the spin cycle, and only for a few minutes (usually no more than two).
Expert opinion
Returning to the question of the need for "high speeds" of rotation of the drum, it should be noted that until recently in Russia there was a stable opinion that what more revolutions per minute during spinning is able to complete the drum of the washing machine, the better and more reliable the entire unit as a whole. In fact, this is not the case. In order not to be unfounded, we decided to turn to practitioners - the specialists of one of the largest Moscow networks for the repair of household appliances "A-Iceberg". Our questions were answered by Andrey Belyaev, manager of the department for the repair of large household appliances, whose work experience in this area is 11 years.
-Andrey Viktorovich is it possible to assert that the number of revolutions of the drum of the washing machine during the spin cycle is indirectly an indicator of technical excellence, greater reliability of the model, and therefore more long term her service?
- No, there is no direct relationship between the number of drum revolutions, the service life and the reliability of the machine. Each model has its own service life set by the manufacturer, and he also undertakes warranty service its equipment, produces spare parts. And even machines with 400 - 600 revolutions per minute (now these are usually narrow and compact models) may well work for more than ten years. True, the service life, which is announced by the manufacturer, is also subject to revision. For example, at the Ariston company, the service life of the machines decreased from 10 years to 7. At the same time, the manufacturer did not provide any official explanations. But many experts believe that this is due to an increase in the number of complaints about the operation of units of this brand, and in fact this indicates a decrease in product quality and the manufacturer's “safety net”. It is worth noting that a similar trend (decrease in quality) is now observed in many companies that produce household appliances... This can be explained by the desire of some companies to reduce the cost of their products, to make them available to a wide range of buyers. Because of this, many resort to purchasing cheaper components - as a result, quality suffers.
And do not they put, for example, reinforced bearings and other specially prepared components on units with a high drum speed?
- They do, but alas, this does not lead to a serious increase in the working life of the same bearings. In principle, even the opposite can be argued - the lower the number of revolutions, the longer some units of the washing machine can work, which is reflected in the service life of the entire unit as a whole. But still, I will emphasize once again that the duration of the washing machine's service and the number of drum revolutions during spinning are not related. Rather, how many years your "automatic washerwoman" will work depends more on the quality of the components. For example, since we are talking about bearings, some companies order them in Poland, but the quality of bearings from this country is worse than, for example, from Sweden, SKF. So it is advisable to choose the machine according to the configuration, and not according to the number of drum revolutions during spinning.
What number of revolutions makes the machine a "high-speed" unit?
- Today, such models are considered to be capable of wringing out with a drum rotation frequency of more than 900 rpm.
Does high-speed washing machines have special devices to reduce the inevitable noise and vibration? And in general, how does a "high-speed" machine differ from a conventional one, except, in fact, the speed of rotation of the drum?
- Differs, for example, in the presence of a processor board that allows the user to independently change the number of drum revolutions while setting the washing program. In addition - the presence of reinforced shock absorbers and suspension springs. As a rule, more modern ones are installed on such models. asynchronous motors... Recently, cars with a new type of motor appear in general - it is "directly" connected to the drum. This avoids the belt drive, one of the main sources of noise during spinning. For example, LG already has such machines.
And yet, there is a direct relationship between maximum number drum speed and spin class of the washing machine. The faster the drum spins, the drier the laundry as a result, the less its residual moisture, which means the higher the spin class. Where is the limit, how much more can you increase the rotation speed - 1600, 1800, 2000, maybe 2500 rpm perfect option?
- Do not increase the number of drum revolutions indefinitely. If you do this, then the laundry will simply tear: microscopic holes will turn into small, small into large, folds on synthetics can become creases
What is the optimal speed?
- More than 1000 rpm is not needed. All the same, for washing wool, silk, fine fabrics, the limit is 500 revolutions. Synthetics cannot be wrung out at a speed of more than 900 revolutions (this is the maximum!). For some things, spinning is generally contraindicated. And as for the notorious residual moisture of the laundry, if you compare it at 500 and 1000 rpm, the difference will be significant, and at 1000 and 1200 rpm it is almost invisible. The residual moisture content of 45% or less (which some manufacturers strive for) is achieved by complex and expensive technical solutions.
Which type of machine is easier to "organize" high revs spin: front or top loading?
- On the one hand, the reliability of "vertical" washing machines is theoretically higher than "frontal" ones. This is due to the fact that in them the drum is fixed on two sides, and not on one, as in front-loading devices. Naturally, this affects the service life of other parts, for example, bearings, which in "vertical" devices are "spaced" to different sides (in accordance with the drum mountings). But on the other hand, the level of vibration during spinning in such washing machines, in general, is higher due to the design features. Therefore, now there is no particular difference between the types in which of them is more suitable for spinning at high speeds.
Are there any alternative methods of spinning the laundry?
- It is difficult to call them alternative, rather it is a symbiosis of methods in which you can wring out the laundry at the "sane" drum speed, and then dry it using a tumble dryer or washing machine with dryer. But there are downsides to this. For example, there may not be enough space to install a tumble dryer. After all, the bathrooms and kitchens in the apartments of many people are very small, and not everyone wants to put such a unit in the hallway or in the living room. Washing machines with dryers are distinguished by their small capacity. As a rule, you can dry in them no more than 3 kilograms of linen, and given that you can usually wash 5-6 kilograms, it turns out that the drying process will take two stages, and this is additional time, and electricity consumption. By the way, many dryers do not use electricity very economically at all. Basically, their energy consumption class is higher than C. In addition, you need to know that laundry that is constantly dried "by machine" wears out faster. This is due to the fact that no matter how hard the manufacturers try, no matter how they improve the drying process, the fibers of fabrics do not always warm up evenly. In some places, a banal overheating occurs, the thing dries up and the fabric becomes thinner.
Output
Well, it seems to us that now everything that is called has fallen into place. The desire of the manufacturer to capture the imagination of the buyer is understandable. After all, the technique must be sold to make a profit. But the catch is that in the process of washing automation, now, perhaps, almost everything has been invented that has allowed the modern development of technology. Breakthroughs and revolutions are not worth waiting for. So the "poor" firms that produce household appliances have to come up with something out of nothing to attract buyers to their new models. "High-speed" pressing is just one of this series.
We hope that those who used to pay attention to this parameter - spin speed when buying a washing machine - will reconsider their approach after our material. Of course, we do not urge you not to be interested in how the machine squeezes. But chasing "centners per hectare" - a large number of drum revolutions during spinning is certainly not worth it. Rest assured - 1000, maximum 1200 rpm is enough for high-quality spinning of terry robes, sheets and towels. We do not recommend squeezing everything else at such speeds.
There is, of course, such a thing as prestige. For some, it is especially important that they have everything better than others. But believe me, if you buy a Swiss Schulthess washing machine (for example, the Spirit XL 1800 CH model), for 75,000 rubles, then it will amaze your neighbors and friends with its cost alone, and, perhaps, design. Of course, you can squeeze out something unnecessary, at 1800 rpm, but only if you really don't need it.
In general, the choice, as always, is yours. We just wish it was meaningful.
In materials about cars, the expressions "high revs", "high torque" are often used. As it turned out, these expressions (as well as the relationship between these parameters) are not clear to everyone. Therefore, we will tell you more about them.
Let's start with the fact that the engine internal combustion it is a device in which the chemical energy of the fuel combusted in the working area is converted into mechanical work.
Schematically, it looks like this:
The ignition of fuel in the cylinder (6) causes the piston (7) to move, which in turn leads to cranking crankshaft.
That is, the expansion and contraction cycles in the cylinders drive crank mechanism, which, in turn, converts the reciprocating motion of the piston into rotational motion of the crankshaft:
What the engine consists of and how it works, see here:
So, essential characteristics of the engine are its power, torque and revolutions at which this power and torque are achieved.
Engine speed
The commonly used term "engine speed" refers to the number of revolutions of the crankshaft per unit of time (per minute).
Both power and torque are not constant values, they have a complex dependence on engine speed. This relationship for each engine is expressed by graphs similar to the following:
Engine manufacturers strive to ensure that the engine develops maximum torque in the widest possible range of revolutions ("the torque shelf was wider"), and the maximum power is reached at the rpm closest to this shelf.
Engine power
The higher the power, the great speed develops auto
Power is the ratio of the work done over a period of time to that period of time. In rotary motion, power is defined as the product of torque and angular velocity rotation.
Recently, engine power is increasingly indicated in kW, and previously traditionally indicated in horsepower.
As seen in the above graph, maximum power and maximum torque are achieved at different crankshaft speeds. The maximum power for gasoline engines is usually achieved at 5-6 thousand rpm, for diesel engines - at 3-4 thousand rpm.
Power graph for diesel engine:
In practical terms, power affects the speed characteristics of a car: the higher the power, the higher the speed the car can develop.
Torque
Torque characterizes the ability to accelerate and overcome obstacles
Torque (moment of force) is the product of force per arm of the lever. In the case of a crank mechanism, the given force is the force transmitted through the connecting rod and the lever is the crankshaft crank. The unit of measurement is Newton meter.
In other words, torque characterizes the force with which the crankshaft will rotate and how well it will overcome the resistance to rotation.
In practice, the high engine torque will be especially noticeable during acceleration and when driving off-road: at speed, the car accelerates more easily, and off-road, the engine can withstand loads and does not stall.
More examples
For a more practical understanding of the importance of torque, we will give a few examples on a hypothetical engine.
Even without considering the maximum power, some conclusions can be drawn from the graph reflecting the torque. Let's divide the number of revolutions of the crankshaft into three parts - these will be low, medium and high revolutions.
The graph on the left shows a variant of the engine that has high torque at low revs (which is equivalent to high torque at low speeds) - with such an engine it is good to drive off-road - it will "pull" out of any quagmire. The graph on the right shows an engine that has high torque at medium revs (medium speeds) - this engine is designed for use in the city - it allows you to quickly accelerate from traffic lights to traffic lights.
The following graph characterizes an engine that provides good acceleration even at high speeds - this engine is comfortable on the track. The graphics are closed by a universal engine - with a wide shelf - such an engine will pull it out of the swamp, and in the city it allows you to accelerate well, and on the highway.
For example, a 4.7-liter gas engine develops a maximum power of 288 hp at 5400 rpm, and a maximum torque of 445 Nm at 3400 rpm. A 4.5-liter diesel engine installed on the same car develops a maximum power of 286 hp. at 3600 rpm, and the maximum torque is 650 Nm with a "shelf" of 1600-2800 rpm.
The 1.6-liter X engine develops a maximum power of 117 hp. at 6100 rpm, and the maximum torque of 154 Nm is achieved at 4000 rpm.
The 2.0-liter engine delivers a maximum power of 240 hp. at 8300 rpm, and a maximum torque of 208 Nm at 7500 rpm, being an example of "sportiness".
Outcome
So, as we have already seen, the relationship between power, torque and engine rpm is quite complex. In summary, we can say the following:
- torque responsible for the ability to accelerate and overcome obstacles,
- powerresponsible for maximum speed car,
- and engine speed everything is complicated, since each value of revolutions has its own value of power and torque.
And in general, everything looks like this:
- high torque at low rpmgives the car traction for off-road driving (such a distribution of forces can boast diesel engines). In this case, the power may become narrower secondary parameter - remember, at least, the T25 tractor with its 25 hp;
- high torque (or better - "torque shelf) at medium and high revsmakes it possible to accelerate sharply in city traffic or on the highway;
- high power engine provides high top speed;
- low torque (even at high power) will not allow the engine to reach its potential: being able to accelerate to high speed, the car will reach this speed for an incredibly long time.
