An automobile engine without a camshaft. Timingless engine - an alternative from Freevalve
Candidate of Technical Sciences D. SOSNIN.
The Arkhangelsky gas distribution mechanism has a centrifugal regulator that shifts the opening and closing moments of the valves depending on the crankshaft speed.
The Arkhangelsky valve opens when an electromagnet is activated and closes with a return spring.
Using two electromagnets to move the valve allows you to get rid of the return springs.
In the new design of the gas distribution mechanism, the drive is located on the side of the cylinder block. The use of long solenoids increases the stroke of the valves, allowing it to be adjusted over a wide range.
Historically, the domestic automotive industry has developed in an attempt to catch up with Western colleagues. Truly original models (they include, say, “Victory”) can be counted on the fingers. And yet, interesting developments, the introduction of which would allow our automakers to successfully compete with foreign ones, appear. We bring to the attention of readers a story about an unusual mechanism proposed by D. A. Sosnin, Associate Professor of the Department of Electrical Engineering and Electrical Equipment, Moscow Automobile and Road Engineering Institute (State Technical University). The device allows you to abandon the use of the usual camshaft in the engine and at the same time flexibly control the valve timing and valve stroke.
WHERE ELECTRONICS FAILS
Any automaker strives to ensure that the internal combustion engines (ICE) on his machines operate in the optimal mode: they provide maximum power, torque uniformity, minimum fuel consumption, and the least toxicity of exhaust gases. However, so far no one has been able to fully achieve this, since the improvement of some characteristics leads to the deterioration of others. Recently, however, significant progress has been made thanks to the use of automated engine control with the widespread use of electronics.
When compiling a program for the control system, the engine is entered into a stable operating mode on a special test bench and all parameters are successively corrected so that for this mode they provide the best output characteristics. The same is done in other modes. The results are recorded in the permanent memory of the electronic unit in the form of a multidimensional diagram, with the help of which control signals are subsequently formed for each of the parameters.
For example, in the integrated electronic system “Motronic” (Germany), which controls fuel injection and ignition, there are five such diagrams: to correct the ignition timing, fuel injection time, recirculation valve position (a device that returns part of the exhaust gases to the cylinder for better afterburning of fuel ), ignition coil energy storage time and throttle position. This system uses engine speed, engine torque and temperature, and battery voltage as inputs. At the output, the compliance of the engine speed with the torque and the content of carbon monoxide in the exhaust gases are controlled.
Unfortunately, the car has a system that cannot be controlled by even the most sophisticated car electronics. This is a gas distribution mechanism with a rigid kinematic connection between the crankshaft and camshaft.
Experts believe that the classic engine is quite perfect and if sometimes it does not work well, it is only because it “suffocates from its own exhaust”; it is worth giving the engine more oxygen, allowing it to “breathe deeply”, and there will be no alternative to it.
You can help the engine if you could shift the opening and closing moments of the valves, primarily the intake ones. I remember how back in the early 70s of the last century, Baltic racers
The republics won the competition, achieving engine speeds of up to 3,000 rpm at idle and up to 8,000 rpm at full throttle. Subsequently, it turned out that they got hold of a camshaft template, welded the cams and then manually finished their shape. With such camshafts, the engines produced high performance (power and torque), but only at high speeds. For sports cars, this is good, but for “private” cars it is unacceptable. Nevertheless, this fact indicates a significant role of the delay or advance of the phase of the valves.
How to make the valve open and close at the moment that corresponds to the optimal operation of the engine? It is clear that it is necessary to control the valve timing depending on the speed, position and load of the crankshaft. The traditional camshaft does not solve this problem.
Within small limits, the valve timing ratio can be adjusted using mechanical, electromechanical, hydraulic, pneumatic valve actuators. But the most promising is considered to be an electromagnetic drive controlled by electronics. With it, you can not only optimize the operation of the engine, but also expand its functionality. Thus, a four-cylinder engine can be made to act like a two- or three-cylinder by changing the order of valve operation; it works more evenly under variable loads, consumes less fuel at maximum speed for a given power. Such an engine will not have problems with changing the direction of rotation of the crankshaft.
At first glance, everything looks very simple, but for some reason solenoid valves on cars are still found only in experimental developments.
VALVE ARKHANGELSK
An attempt to implement the idea of a solenoid valve with flexible control was made in the middle of the 20th century by MADI Professor V. M. Arkhangelsky. The electromagnets were turned on and off when the contacts connected to the camshaft cams were closed and opened. The valve was returned to its place by a spring.
In the Arkhangelsky scheme, a centrifugal regulator was provided on the camshaft. When changing the speed, it shifted the position of the cams and caused the valves to open and close ahead of time. Thus, the regulator played the role of feedback. This made it possible to do without program control, which, by the way, could not exist then.
Unfortunately, despite the elegance of the scheme, it was not possible to create a workable design. The fact is that the valve must operate quickly and close reliably, and therefore a return spring with high rigidity is required. Accordingly, a powerful electromagnet is needed, which consumes significant current from the vehicle's on-board network. In those days, there were no powerful semiconductor valves, and metal contacts quickly burned out when switching high currents. Finally, when the valve was closed by a return spring, the valve head hit the seat hard, which caused noise during the operation of the gas distribution mechanism and led to frequent valve failures.
ONE IS GOOD AND TWO IS BETTER
You can get rid of many of the shortcomings inherent in the Arkhangelsky valve if you put two electromagnets instead of one - opening and closing. A similar scheme was developed by one of the students of Togliatti State University in a graduation project under the guidance of Doctor of Technical Sciences, Professor V. V. Ivashin.
In this variant of the design, springs are not needed, and therefore electromagnets can be smaller in size and power - after all, a large current is consumed only when closing and opening valves, and ten times less current is sufficient to hold them.
But most importantly, now you can do without a camshaft at all, since a programmable controller can set the response time and current strength through the electromagnet winding - an electronic device, usually on a microprocessor, that controls the operation of the engine and other vehicle systems.
In NAMI, under the guidance of Candidate of Technical Sciences A. N. Terekhin, they began to carry out research and design development of a gas distribution mechanism with an electromagnetic valve drive based on the M-412 engine. As a result, a working model of a gas distribution mechanism with two-way electromagnets on eight valves was created. But since the beginning of the 1990s, funding has ceased, and promising development has been lost in the archives.
A few years ago, work on a new gas distribution mechanism was resumed at the Volga Automobile Plant under the leadership of P. M. Prusov, the chief designer of AvtoVAZ. So, among the topics of the All-Russian competition “Russian Automobile” (see “Science and Life” No. 12, 2002), “Development of an electromagnetic drive system for gas distribution valves for a 16-valve VAZ engine” was announced. Two projects were submitted to the competition, but both were completely “out of business”, and they were not even considered.
Meanwhile, Japanese, American and (with the greatest success) German automakers began to work on improving the electromagnetic valve drive. Already in 2002, BMW began testing a gas distribution mechanism with an electromagnetic drive of all valves on a real 16-valve engine.
COMPETITIVE DESIGN
At the same time, the development of electromagnetic gas distribution valves was started at the Department of Electrical Engineering and Electrical Equipment of the Moscow State Technical University (GTU).
Although in the West we were not recognized as competitors: they say, “were 10 miles behind” (in the jargon of racing drivers they say that they are two laps behind, which means weaklings), but the author has patented a design that solves most of the problems inherent in electromagnetic drives.
In it, instead of bulky electromagnets mounted above the valves, long solenoids are used. The braking of the core in a long solenoid is implemented not by hard stops, but by edge magnetic fields, and the drive operation becomes silent. In addition, the valve stroke can be arbitrarily large and adjustable. The reciprocating movement from the electromagnet to the valve is transmitted through the rod and the rocker arm. Due to this, the drive can be installed not above the cylinder block, but on its side surface. As a result, the height of the engine is significantly reduced, and regular vehicle systems are used to cool and lubricate the drive parts.
Now it's up to the engine builders. If it is possible to translate the idea into metal, a torquey and economical car will appear in Russia, which, moreover, will meet the most stringent requirements for exhaust purity.
Hypercars Koenigsegg are cars whose production began not long ago, but they have already loudly declared themselves and found their place in the class of such cars. There were quite a few such moments in history, but these odious projects ended in failure. But he survived and competed with the luminaries of the world of super motors.
For 15 years now, Koenigsegg engineers and designers have been working on a project for a camshaftless engine that will not have a throttle. But the very fact of the absence of a throttle valve has already been proven by BMW and Fiat engineers, but they have not been able to finalize the design to perfection. The Bavarians removed the damper, installing an electronic intake valve control system instead. The Germans' problem was that they used an additional electric motor to implement their project, which complicated the entire structure and steadily led to additional breakdowns. Fiat engineers faced another problem that they still cannot solve (high pump losses). The Swedes took a different path, leaving the Bavarians and Italians in the background of history, since their system was able to control all the valves separately, independently of each other.
So what is a Swedish engine without a camshaft?
The problem with all big engines is gluttony. Therefore, the Swedes decided to make the engine for their hypercars economical and powerful at the same time. Many have heard about powerful Swedish engines, one 1500-horsepower engine in Agera-R is worth something, but fuel consumption and engine dimensions leave much to be desired. It was decided to take as a basis the engine developed by one American self-taught mechanic Carmelo Scuderi. The essence of the idea is that he divided the cylinders into working and auxiliary. The workers burned the fuel mixture and released the exhaust gases, and the auxiliary let the fuel in and compressed the mixture. The cylinders were connected by bypass channels, in which there were two valves - expansion and compression. The process safely dispensed with the camshaft.The Koenigsegg engineers decided to upgrade the Scuderi engine and implement everything in one cylinder, but for this they needed to develop a progressive model of the valve actuator. It must be fast, accurate and without sticking. By 2000, they built the first engine with a similar scheme of operation, which consumed methane and hydrogen. The level of emissions of harmful gases into the atmosphere was so low that only electric motors are below it. Everyone was immediately interested in such a unit, and especially its actuator, although it was bulky, pneumatic, had a lot of vibration and a high noise level. After 3 years, the engineers completely modernized it, added a hydraulic valve lock and reduced the size. It took several more years of upgrades, until a fully finished prototype could be installed on a standard engine. The Saab 95 became the first such car. Engine power increased by 30%, fuel consumption decreased proportionally (also by a third).
In describing the principle of operation of their motor, the Swedish designers used a funny allegory. They suggested imagining an ordinary piano-shaped engine and trying to play with a stick or a mop. And in the Koenigsegg engine, the interaction of fingers and keys was positioned directly, without an intermediary. Also, for greater persuasiveness, one can compare a mono-injection and a distribution injection system, when fuel is injected directly into the working area of the cylinder, bypassing the distribution frame. The effectiveness of individual influence on various processes in the engine has been proven for a long time and is used by many manufacturers. But how to make the valves let in and out something without a special device that regulates all cycles? For this, fast actuators (electronic pushers) are needed.
The control unit sends a signal to the actuator, which opens and closes the valve. The pushers are equipped with pneumatic springs with an adjustable level of stiffness and valve position sensors. The entire algorithm of operation of the cylinders and all auxiliary systems of the engine is controlled by a computer, thanks to which you can change the valve timing as you like and as many times as you like. You can turn off any number of cylinders at any time.
The motor can work alternately in different cycles, depending on the tasks and the load level. It can work in standard mode for all internal combustion engines, it can be economical, it can be super economical, it can work in a cycle with a variable compression ratio (Hedman cycle). These cycles cannot be implemented within the design of a standard internal combustion engine, so manufacturers have to choose. For example, the famous Hedman cycle, which can only be used with electronic control of lift and valve timing, can alternately work with the Otto principle (traditional thermodynamic cycle of all engines) or Atkinson (increased fuel economy).
The versatility of such an engine affects the fact that it can run on both gasoline with different octane ratings and diesel fuel. In addition, it is 30-50% more economical, a third more powerful, it has higher torque, it weighs less and is more compact in size. Light weight and compact dimensions with more power and low consumption will give Koenigsegg hypercars a huge advantage over competitors. The issue of noise level, power consumption and vibrations remains unresolved. But of course the installation cost. The price of such engines is very high and only mass production on civilian cars can reduce it. In addition, such an internal combustion engine can be used not only as the main one, but as an additional one in hybrid versions.
If the Swedes manage to get rid of the high level of noise and vibration and they are able to optimize energy costs, then the unit will be in high demand, since such an engine is economically justified and expedient. And in the presence of stable demand and mass production, the price may fall to optimal levels.
I am sure that many of our readers are aware of the existence of a company called. Koenigsegg. But we are also sure that you have heard almost nothing about its subsidiary called FreeValve.
If this is true, then welcome to the world of high auto technology. The Scandinavians have developed and are implementing an extremely interesting product, a new (this is not an exaggeration) type of engine in which there are no such details familiar to everyone associated with cars, such as an engine camshaft.
If you look back, in the 80s, the VTEC type valve control system became the top and most advanced technology, the 90s were distinguished by the development and application of an advanced fuel injection system, a little later, the development of direct injection became the culmination of the late 2000s. The future lies with FreeValve technology, which "without a camshaft system" drives the valves in the internal combustion engine. But is it really? Let's take a look together.
Like any other technological revolution, which should (or should?) Change the balance of power in the technology of creating internal combustion engines. The basic principle sounds simple and ingenious, instead of being tied to a specific, static formula, the new technology offers flexibility in how the motor works.
Variable valve opening technologies have been around for a relatively long time, there have been many prototypes from different car manufacturers, there are even similar production versions from BMW, but none of them can match the possibilities offered by a new type of engine developed by a modest Scandinavian company. The genius of the system being promoted is also, not least, that it does not involve major changes in the design of the engine itself. Nevertheless, this apparent simplicity did not help FreeValve to avoid the high cost and. The law of business, new items always cost a lot of money.
MotorFreeValve30% more powerful, twice as environmentally friendly and 20-50% more economical than a conventional camshaft engine
Like other engineers focusing on both variable compression and variable displacement, the guys at FreeValve have been working on what is called the world's top motor technology at the forefront of progress.
Through research, Koenigsegg found that valve actuation technology had a huge development potential, the decision was logical to develop a real system based on theoretical experience, thus, in order to achieve ambitious goals, they merged with a subsidiary of Cargine, later renamed FreeValve.
The introduction is over. Let's move on to the details.
Let's move on to exploring all the nuances of FreeValve technology, which was publicly disclosed to the public not so long ago.
What is the difference between a system without camshafts and classic valve actuation technology
From the name and description of the technology, it becomes clear that we are really talking about an engine in which there are no camshafts. Actually an unusual approach to the engineering of in-engine technologies, the main secret of which is that the engine does not need these shafts, since the valves are designed to work individually, each separately. Each valve is not rigidly connected to neighboring valves, hence the name "free valves", FreeValve.
The main idea is that the operation of the internal combustion engine has become more efficient in all phases of work. Standard camshafts, due to their design features, are extremely compromise options, which often leads to certain “victims”, increased fuel consumption for the sake of power or low torque at high speeds for the sake of peak power, etc.
The engine can operate in four cycles: standard - Otto, complex - Miller and economical - Atkinson. The engine is also capable of reproducing the Hedman cycle with a variable compression ratio.
For example, in a spark ignition engine (read, in a gasoline engine) with FreeValve installed, you can safely remove it, and the efficiency of even a powerful gasoline engine will become akin to a diesel version.
As a result, the resulting power unit will be cheaper than an equivalent diesel engine, FreeValve says. Newfangled electronic valve actuators can also be installed on diesel engines, which in theory should slightly reduce engine consumption and seriously improve the environmental friendliness of its exhaust.
The cost of new technology. If we take into account the science of economics, it turns out that the first 10-100 thousand engines built using this technology will cost more than conventional types of power units, but in the end, when production is put on an industrial flow and when a certain “critical mass", the cost of new types of motors will begin to gradually decline and eventually equal the cost of a standard internal combustion engine.
At the same time, such motors will be more efficient than traditional models, will consume less fuel with increasing power and will show much more acceptable torque shelf performance.
What happens if the system fails?
Adherents of the classical engine scheme and those people who cautiously accept all updates and technical innovations are probably wondering how bad everything will be if the newfangled system breaks down. And in general, is it reliable?
It is foolish to deny, any, even the most reliable device, can produce an unpleasant misfire, and you should also not forget about design defects that may not be detected at the initial stage of development. The result is predictable, expensive damage. But here, too, FreeValve has a small consolation trick up its sleeve.
Incredibly, this engine will be able to function normally even if one or more valve actuators fail, of course this will affect peak power at high speeds, but as the developers assure, the difference will be negligible.
An emergency operation of the engine is provided, it consists in the fact that even if 75% of the valve actuators fail, the car will be able to independently get to the service station, incredible survivability. Testing continues ... but the most important thing that the developers still can not overcome in any way is the endurance of this type of drive. Everything is fine in it, but the stumbling block is that the system does not nurse for a long time. However, this is a temporary phenomenon and it will be possible to neutralize it, because the engineers have found out by theoretical calculations that the reliability of such a system can be comparable to a standard internal combustion engine. Hundreds of millions of drive cycles have been simulated, no noticeable wear has been found. It remains to put the knowledge into practice and you can leave.
The Swedish company compares the current camshaft technology to playing a piano with two hands, each tied to opposite ends of a broomstick. Using each finger individually, as pianists do, will allow for individual valve control.
From the above, we can conclude:
1. At the moment, the technology is clearly raw. The engine is not able to go as long as motors with a conventional camshaft system go without serious problems.
2. But even at this stage of development, the system showed its best side. Not a single engine with a standard gas distribution system is able to work at least somehow normally if 75% of the valves stop working (let's imagine this hypothetically). Moreover, stop functioning in normal mode at least one of the valves on conventional ICEs, you will lose more than peak power at high speeds. That is, in terms of breakdowns, if something has happened to the timing, Scandinavian technology clearly bypasses all other types of motors.
Another plus. On a revolutionary engine, according to the engineers working on the project, it is impossible for the valves to meet the pistons in the event of a broken belt / chain stretch, because it is simply not here.
Technical nuances. FreeValve - more than fully variable valve timing?
The short answer, to the point, is yes, it is more than a variable valve timing engine, because each specific valve can have different “lifts”, both in time and in the opening position. It can also open and close at different speeds, changing the frequency, this is monitored online by the on-board computer system, calculating the required valve stroke mode in accordance with the engine operating mode with a lifting accuracy of up to 1/10 of a millimeter.
As you can see, the drives (actuators) are able to do this with extraordinary accuracy, significantly exceeding the performance in a conventional engine.
A subsidiary of Swedish supercar manufacturer Koenigsegg is working on a new type of valve system for internal combustion engines. The new system will completely depart from the classic scheme, which implies the presence of camshafts, which is why it was called "Camless", "no camshaft". FreeValve has published a , which shows the operation of the new revolutionary engine in detail.
The main part of the engine, which actually makes it special, is the pneumatic actuator of the engine valves. Pneumatic valves control the operation of the system. With the help of Camless engines, manufacturers will finally be able to synchronize the valve timing in engines. Each combustion phase will be adjusted according to the conditions, the engines will become lighter and produce more power, while increasing efficiency. The system developed by the Swedes makes it possible to control the combustion cycle of each cylinder.
The operation of the engine is based on the pneumatic actuator of the valves, which open and close under pneumatic or spring pressure. Each of the valves can be adjusted individually, which allows you to smoothly adjust the height of the valve lift and the duration of its opening, as well as simply deactivate a specific cylinder if necessary. Another advantage of the pneumatic valve system is that it draws less energy from the engine than classic camshafts.
All the above-mentioned nuances of the new type of engine make it possible to significantly increase the output power (up to 30% increase in power and torque) and also improve fuel efficiency (also up to 30 percent). At the same time, engines with a revolutionary system will become more environmentally friendly, and the amount of harmful emissions will significantly decrease.
If the whole system is so cool, why aren't all automakers putting it into service immediately? Why are they not in a hurry to do it? The two main weaknesses of the system remain quiet operation. They also hinder progress.
But even if the "camshaftless" system takes root, it will most likely only be able to extend the life of the internal combustion engine for a while, then no one doubts that this type of engine will retire sooner or later.
Christian von Koenigsegg smiles: "A few years ago, a GM engineer said that we would never see an engine without a camshaft. At the moment we are driving a car without a camshaft. It turns out that he was wrong." Welcome to the future.
Under the wing of Koenigsegg lives a small company called Freevalve. What they do is just incredible. You see, in engines there is such a thing as a camshaft. It has cams that open and close valves during rotation. This element has been present in engines since their inception.
The system works unquestioningly, but the valves are not always open or closed. There is an intermediate stage, which is not effective. However, engineers stubbornly think that a camshaft is the only solution available. How is it? Why not go crazy and come up with some absurd idea - for example, related to compressed air?
The Freevalve engine got rid of the camshaft and throttle body, replacing them with pneumatic actuators on each cylinder. This concept has been around for a long time. The ships use an electromagnetic valve opening mechanism. This means that the concept has proven itself. It remains to reduce it to the scale of something more ordinary.
This system provides completely independent control of each cylinder and each valve. If you have 4 valves, then only two open when necessary. With a conventional camshaft, this cannot be achieved. Freevalve can disable one cylinder, two, three, and so on.
Another surprising thing is that the system is able to work in different modes. At low revs, the engine can operate like a two-stroke, which greatly improves power delivery: 3000 rpm feels like 6000 rpm. The engine can work on the Miller cycle (like the Mazda Xedos 9): although it is complex, it is much more efficient. Well, plus everything, the engine can run on several types of fuel. Christian emphasized that gasoline and diesel can get along together. Of course, we are not talking about their merging into a single mixture. Two separate tanks would be a great idea.
The most impressive part, however, is that with current engines, the system will provide 30% more power and torque and 50% more fuel economy. It will also reduce the size of the engine. So a compact engine built from the ground up can compete with much larger engines.
Christian described the camshaft operation as "playing the piano with a broom", while the Freevalve is genuine "finger play". You will have a higher level of control. Since all elements work independently, one cylinder or actuator can fail and the engine will continue to run for many more years.
In a short ride in the Saab 9-5 Freevalve used to develop its technology, the Jalopnik reviewer felt like he was in a normal car. Isn't that the best praise for any innovative method? At low revs, the engine feels a bit like a diesel, but over time its work smoothes out. The system is functioning, but the engine software is still in its infancy. The Swedes have to improve it, but they have time. Before us is a fifth-generation system, and a sixth is already looming on the horizon.
Christian does not believe that this technology will save the internal combustion engine from extinction, but it can significantly extend its life. Just imagine that this idea could have come to fruition 10 years ago. Where would the ICE be today?!