Candidate technical sciences D. SOSNIN.
In the scheme of the gas distribution mechanism of the Arkhangelsk there is centrifugal regulator, shifting the opening and closing moments of the valves depending on the speed crankshaft.
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, it has been domestic automotive industry 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 car manufacturer strives to ensure that engines internal combustion(ICE) on his machines worked in optimal mode: provided maximum power, torque uniformity, minimum fuel consumption, least toxicity 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 permanent memory electronic block 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 a complex electronic system“Motronic” (Germany), which controls fuel injection and ignition, 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), energy accumulation time in ignition coil and position throttle valve. 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 classic engine perfect enough 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 the speed of the crankshaft up to 3000 rpm on Idling and up to 8000 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, engines gave out high performance(power and torque), but only on high speed. For sports cars this is good, but for the “private” 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 on maximum speed at 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 an idea solenoid valve with flexible management was undertaken in the middle of the 20th century by Professor MADI 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 a role feedback. This made it possible to do without program control, which, by the way, then could not be.
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 a significant current from onboard network car. 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 breakdowns valves.
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 version 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 - electronic device, usually on a microprocessor, work manager 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 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. Yes, among the topics All-Russian competition"Russian Automobile" (see "Science and Life" No. 12, 2002) was announced "Development of an electromagnetic drive system for gas distribution valves for a 16-valve VAZ engine." 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 company began testing on a real 16-valve gas distribution engine with an electromagnetic drive of all valves.
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 race car 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 stops. magnetic fields, and the drive 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 for cooling and lubricating the drive parts are used standard systems car.
Now it's up to the engine builders. If it is possible to translate the idea into metal, a torquey and economy car, which will also meet the most stringent requirements for exhaust cleanliness.
Today classical principle it is difficult to imagine the operation of the gas distribution mechanism of an internal combustion engine without the main timing units: camshafts, drive belts and timing chains, drive gears, as well as cams and pushers.
Undoubtedly, many leading manufacturers of internal combustion engines have subjected this seemingly simple mechanism to a complex modernization. Take for example the variable valve timing system (VTEC) and other timing bells and whistles that allow you to turn off the operation of individual pistons to save fuel.
And, it seemed, how can one get rid of this harmoniously coordinated work of the mechanical elements of the gas distribution mechanism. If you approach radically, you can simply change the internal combustion engine to an electric motor. But is it still about how to get rid of the classic timing scheme in the internal combustion engine?
It turns out that since 2005 there has been such a solution, but only it is used on the small-scale sports car Koenigsegg CCXR. Max speed sports car 388.87 km / h, and the acceleration time of 300 km / h is only 11.92 s. This sports car is named after the creator of Christian von Koenigsegg. But the system that replaced the traditional timing was called Freevalve, which means “free valve”.
The creator of this technology does not move on a sports car, but on a modest Saab 9-5, which at first glance is no different from its counterparts. But if even not the most experienced motorist opens the hood cover of the engine compartment, he will see with the naked eye an unusual picture for himself. No, drive gears, timing belt, "bed" camshaft. What drives the valve?
So, the so-called Freevalve system actuator provides the movement of clans, the principle of which is based on the integrated use of electrical, hydraulic and pneumatic energy. The input of the Freevalve block is fed electricity, which actuates the pneumatic mechanism of a single actuator to open the valve, and hydraulically to close it. In other words, electric actuators supply air and oil, thereby ensuring the movement of the valve.
Each actuator is completely independent of the others and is controlled by a remote control unit. The creator does not disclose the details of the innovation system, but following the logic this block control must work in conjunction with the fuel supply system to ensure synchronization of valve opening and fuel injection timing.
The demo graph of the Freevalve valve control system shows the obvious benefits.
The red line shows the characteristics of the intake valves, the blue line shows the exhaust valves. Unlike the classic timing scheme, where both intake and exhaust valves open smoothly with the help of an elliptical camshaft, in the Freevalve system they open almost instantly under the influence of an electrical impulse.
Accordingly, the movement of valves with the Freevalve system has the shape of a trapezoid with almost right angles, and the schedule traditional system Timing - the shape of a parabola. Thus, the time for gases to enter the exhaust and exhaust ports has been significantly reduced, while improving power and environmental performance with an equal engine size. On the test bench, the Freevalve engine showed a 30% increase in power and a 50% reduction in harmful emissions.
With the help of Freevalve, the mechanism for changing the valve timing is much easier to solve. Such known systems like VTEC, this is achieved by a complex design of camshafts that can be mixed relative to the axis of the drive gears. Japanese manufacturer Honda has introduced Variable Cylinder Management (VCM) technology since 2003, which allows you to turn off the cylinders and only work parts piston group to save fuel in cruise control mode without loads. Structurally, this is done by a complex placement of cams that could move along the camshaft providing the operating and standby operation of the piston.
In the case of Freevalve, providing such functionality does not require additional mechanical implementations and upgrades. All this is achieved by firmware of the actuator control unit.
Further increase power and reduce emissions harmful substances into the atmosphere by installing additional exhaust valves. Part of the exhaust gases can be sent to the turbocharger, and part to the catalyst.
According to the inventor, the Freevalve system can be installed on any internal combustion engine. But this is only theoretical. In practice, these adaptation options are not yet entirely clear. First, when installing old car it will be necessary to provide a unique corpus for each instead of valve cover, where the actuators will be mounted in turn. Secondly, it is not entirely clear how the relationship with fuel system, which is controlled by the regular brains of the car.
Also, when removing the same camshafts, drive gears, it will be necessary to get rid of all kinds of sensors, in the absence of which the car's brain will experience a cramp. Of course, for new cars, the advantages are undoubtedly obvious, but in terms of adaptation, existing cars the question is still open.
So, let's sum up and subvolume the pros of the Freevalve system with electronic actuators:
- The weight of the engine is reduced by eliminating gears, drive belts (chains) and timing camshafts.
- The compactness of the engine and the increase in the engine compartment.
- An increase in engine power by about 30%.
- Reduced emissions of toxic gases into the atmosphere.
Which does not need a transmission, has been developing for 15 years innovative engine internal combustion - without camshaft and throttle. "Motor" understands the principle of operation of the miracle unit.
####What's happened?
The Swedish company FreeValve, a partner of the Swedish supercar manufacturer Koenigsegg, has published a video demonstrating the operation of a fundamentally new internal combustion engine, where instead of a traditional camshaft, electronically controlled valve actuators.
The Swedes claim that such a motor is capable of consuming fuel with almost any octane rating, turn off any number of cylinders, and also work in any of the three main thermodynamic cycles.
####Where did he come from?
The development of a fundamentally new motor in the early 2000s was taken up by Cargine, whose partner since 2001 has been Koenigsegg.
The goal set by the Swedish engineers was to create a new generation of economical and environmentally friendly motor. The concept of the Carmelo Scuderi engine was taken as the basis, in which the cylinders are divided into working and auxiliary. The former are responsible for the combustion of the mixture and exhaust, and the latter for intake and compression. working mixture. True, unlike the Scuderi engine, the Swedes wanted to implement this scheme inside one cylinder, for which they needed a fast and very accurate valve actuator.
In 2000, the first single-cylinder unit was prepared, capable of operating on methane or hydrogen. The level of emissions of nitrogen oxides from this engine turned out to be incredibly low, but the auto industry was not even interested in the engine itself, but in the pusher used in it.
True, the first version of the pusher was completely pneumatic and had many drawbacks: it was too large, too noisy and vibration-loaded. Therefore, the engineers decided to add to the actuators hydraulic element for fixing valves and additional damping.
By 2003, the first prototype of the actuator was prepared, the dimensions of which already allowed it to be used on conventional engine, however, it took several more years, during which engineers changed its design several times, before the first truly working version of the electronic valve control system was ready for testing.
The first prototype of the engine without camshafts was installed on the Saab 9-5 station wagon. The output of this engine turned out to be 30 percent higher than the serial unit, and fuel consumption decreased by a third. It is clear that the technology still needed to be refined and adapted for mass use, however, the inspired creators hoped to launch new engines in the foreseeable future in the foreseeable future. mass production. Engines without camshafts were supposed to appear on the new Saab 9-3 sedan and 9-4X crossover - Cargine was part of an alliance of Scandinavian companies that tried to buy out the Saab brand during the 2008 crisis. However, this venture ended in nothing, and Saab was sold to the Chinese.
Since then, Cargine's only automotive partner has been Koenigsegg. Its head, Christian von Koenigsegg, once admitted that he had long dreamed of using the technical developments made by his company in mass machines. Perhaps he meant just economical and efficient engine without the camshaft he was involved in developing?
####So how does this engine work?
“If you imagine that the engine is a piano, and the valves are its keys, then using a camshaft is like playing an instrument with a mop instead of fingers,” Koenigsegg describes the advantages of his motor.
Its own - because for some time now Cargine has been renamed Freevalve and is under the control of the Koenigsegg group. Nine engineers are working on the project of a motor without a camshaft, capable of “playing any music”.
Instead of a camshaft, the opening and closing of the valves is controlled by very fast electromagnetic actuators at the command of the computer. They use air springs that can change their own stiffness, and special sensors for monitoring the position of the valve. The latter control the position of the valves one hundred thousand times per second with an accuracy of one tenth of a millimeter, and their operation requires about a hundred times less energy than analogues from other companies.
This design allows you to endlessly change the valve timing, as well as at any time disable and enable any number of cylinders, depending on specific loads. Such a motor can operate according to the traditional thermodynamic Otto cycle, the economical Atkinson cycle, as well as the more complex Miller cycle, which provides the motor with even more high efficiency and economy. In addition, this motor can simulate the Hedman cycle with variable degree compression, which became possible to manage precisely thanks to valves with electronic control of lift and opening time.
The state-of-the-art unit designed by Freevalve is 30 percent more powerful and has more torque at low revs, compared to analogues of the same volume, but at the same time 20-50 percent more economical and emits half as much harmful substances into the atmosphere. Finally, it is capable of consuming both gasoline with various octane ratings and diesel fuel.
Christian von Koenigsegg notes that new units can be made more compact and lighter than traditional internal combustion engines by eliminating camshafts, throttle and the corresponding attachments. The freed up space can be used to improve safety or increase the free space under the hood.
####Wait, but motors with no throttle and electronically controlled valve lift are already made by BMW and even Fiat?
Indeed, the Bavarians were the first to abandon the throttle by introducing an electronically controlled intake valve control system into the gas distribution mechanism. However, the Bavarians use a rather complex mechanical system with an additional electric motor, and the Fiat MultiAir design has not yet solved the problem of high pumping losses.
Freevalve technology, in turn, is able to control all valves independently of each other, combining strengths all existing thermodynamic cycles in one power unit.
####When to expect?
The release of a motor without camshafts is considered economically justified now, despite the need to solve the remaining problems with high consumption electricity, noise and vibration. But its main disadvantage is the high cost of production. Which, however, can decrease in case of mass application of new technology.
A very controversial topic on the internet. Some people say that this is the future, while the other part says that there is nothing new here, all this has long been known and is not done in large quantities, because it is not reliable, complicated and meaningless.
Yes, there is still such an opinion: how much can you improve the "ancient mechanism", you need to create something fundamentally new! In any case, let's see what we are talking about and draw our own conclusions.
In 2005, a car named after Christian von Koenigsegg officially became the fastest production car on the planet: experts from the Guinness Book of Records recorded a speed of 388.87 km / h. Koenigsegg CCXR has become the world's best sports car in terms of weight and power. Koenigsegg One:1 is the leader in the category " best overclocking”, reaching a speed of 300 km / h in just 11.92 seconds.
While the most efficient sports cars in the world break record after record, their creator drives around in an old Saab 9-5, smiling slyly. Under the hood, the “old man” has the only engine in the world that has no camshaft, no cams, no valve lifters, no notorious timing belt. And, unlike the frenzied Koenigsegg, intended only for the rich and famous, motors with individual valve drives promise to be the first truly mass creation of the Swedish inventor.
Between two elements
In the cylinder head of the test Saab, as expected, 16 valves work. Each is driven by a separate actuator and each is commanded to open or close by the engine control computer independently of the others.
The actuator is the core know-how of Freevalve, a subsidiary of Koenigsegg. Many developers have tried to supply each valve with an individual drive and control them independently of each other, including many world-famous automakers. The most obvious solution in the form of linear electric motors (solenoids) does not lead to the desired result: small motors do not have enough power to accelerate the valves to desired speeds(20,000 openings and closings per minute), there are problems with cooling and reliability.
Christian von Koenigsegg does not go into details of how his actuator works, but he is happy to explain the general concept of the "pneumatic-hydraulic-electric actuator". The valves are opened by pneumatics and closed by hydraulics. Both pneumatic and hydraulic systems constantly under pressure and ready to give the valve maximum energy. The task of the electric actuator is only to supply air or oil to the valve in time. The problem of cooling and lubrication is solved by itself: the most loaded parts of the drive are serviced by the corresponding systems of the internal combustion engine itself.
The beauty of the Freevalve actuator is that it fits almost any automotive or motorcycle engine. Whether it's a high speed motor racing motorcycle, spinning up to 16,000 rpm, or a truck diesel rattling at 3,500 rpm, the same drive will fully meet their needs. The race bike valve is made of light alloy, so the energy of the actuator easily accelerates it to high speeds. The truck valve is large and heavy, but high speeds he doesn't need.
Breathe into all valves
The red graph shows the opening curve inlet valve, blue - graduation. It is clearly seen that the valves remain in the fully open position for as long as possible - the graphs have an almost rectangular profile, while with a conventional timing they would be more like parabolas. The required volumes of gases pass through the Freevalve valves in less time than usual, so short intake and exhaust phases do not overlap. This is the reason for the almost two-fold improvement in environmental performance.
On the piano with a yoke
“Using a traditional camshaft instead of a Freevalve is like playing a piano with a yoke instead of fingers,” says von Koenigsegg. What kind of problems does the inventor want to solve by programming the behavior of each valve separately? We list them in ascending order of interest.
The most obvious: for different engine operating modes (primarily crankshaft rotation speed), there is an optimal composition air-fuel mixture, their right moments opening and closing valves. Traditionally, this problem is solved using a variable valve timing mechanism (for example, VTEC): the entire camshaft rotates slightly relative to the timing gear (timing), and all valve opening and closing moments are shifted forward or backward.
The problem with VTEC lies in the limited number of modes, while individually controlled valves allow you to revise the optimal set of parameters for any, even the smallest change in speed. But the main thing is that Freevalve allows you to change not only the moment, but also the duration of the valves opening.
But what if we want to flexibly control engine power by turning off part of the cylinders? IN modern engines The problem is solved with the help of complex mechanism: for each valve, two cams are provided, which replace each other, moving along the camshaft. One cam provides regular work valve, the second is responsible for the operation of the cylinder in the "standby mode". Freevalve valves allow you to turn on any program for any cylinder at any time without any mechanical tricks.
But still the main problem The traditional timing lies in the elliptical shape of the cam, due to which the valve is almost never open or completely closed. Instead, it always either opens smoothly or closes smoothly, which lowers it. throughput. Moreover, this feature leads to the fact that at certain moments the inlet and exhaust valves are open at the same time, and this adversely affects the environmental performance of the engine.
Christian von Koenigsegg demonstrates the valve opening curve on the monitor of a special device. It resembles a rectangle: the valve opens abruptly, is held open, and then abruptly closes. This is not the eternal sad ellipse of a traditional valve. It is especially interesting that the curve retains its angularity even for high revs(up to 10,000 rpm) - the actuator has enough power to open and close the valve really quickly.
Perhaps it was the latter property that most contributed to the fact that the test engine with free valves showed impressive results on tests: it produces 30% more torque, consumes 30% less fuel and gives a 50% reduction in harmful emissions.
Three cylinders, eighteen valves
Freevalve valves allow the cylinder head and the engine itself to be made much more compact. But this is far from the only layout advantage. It is possible to increase the number of valves per cylinder by dividing the functions between them. For example, to send one part of the exhaust to the supercharger turbine, and the other - directly to the catalyst, for environmental reasons. Special valves are also useful in order to turn the car into a pneumatic hybrid.
Down with canons!
Freevalve is more than meets the eye. Firstly, the system can significantly change the appearance of the car. Camshaft and valve lifters take up a lot of space in the cylinder head, and they weigh a lot. Four cylinder engine the Freevalve is similar in size and weight to a three-cylinder. If we take into account that independent valves give a significant increase in torque, then two cylinders can be dispensed with altogether. And then the tiny motor can be hidden even under the seat.
The system allows you to switch the engine to an exotic work cycle at any time, even Miller, like on Mazda, even Atkinson, like on Prius. Why be modest: if desired, the motor can become two-stroke in the blink of an eye, almost doubling the power! Von Koenigsegg dreams of cars with two fuel tanks and power supply systems: for gasoline and diesel. For the transition to biofuels, the flexibility of settings is also relevant.
But the most interesting fantasy of the inventor is a pneumatic hybrid. Using a special valve configuration, it is possible to turn the internal combustion engine into a compressor, which, when braking, will pump air into the cylinder, accumulating pressure. Compressed air can then be pumped into the cylinders to accelerate the car, or used as a powerful alternative to turbocharging, briefly boosting engine power.
Perhaps the most unexpected property of an engine with independent valves is reliability. Every driver is afraid of a broken timing belt: if the piston “catches up” with the valves, the same will happen in all other cylinders. An expensive cylinder head, and with it pistons, and possibly connecting rods with crankshaft will be seriously damaged.
And with Freevalve, everything is simple: no timing - no problems! If one cylinder suddenly "knocks" - all the rest will remain safe and sound.
Wolf in sheep's clothing
An old Saab, which got an experimental version of the timing belt with independent valves, drove 60,000 km with it, having seen both summer heat and 20-degree frosts. The cylinder head was made from the original "Saab", throwing out everything superfluous from it and turning new channels for hydraulics and pneumatics. Our colleagues from Jalopnik.com took a ride on the "old man" and noted that at speeds up to 3000 rpm it shows diesel habits - it characteristically taps the valves and produces crazy torque.
Christian von Koenigsegg smiles: “A few years ago, a GM engineer said that we would never see an engine without a camshaft. this moment we are driving a car without a camshaft. Turns out 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.
However, the most impressive part: in relation to 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 more high level control. Since all elements work independently, one cylinder or actuator can fail and the engine will continue to run for many more years.
During a short ride in the Saab 9-5 Freevalve used to develop its technology, the Jalopnik columnist felt like 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 works, but software engine 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?!