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Freevalve - A New Beginning For Combustion In Times Of The Old

James Bickham

HV Battery Support Technician

发布日期: 2020年7月18日

In this article, I shall discuss the revolutionary technology that the company Freevalve has engineered for the development of the modern engine, by adding independence to the existing system. I shall also talk about how it will perform wonders in the automotive world that we live within today, and how it will impact us within the next decade onwards from 2020.

How do conventional engines operate?

Most conventional IC (Internal Combustion) engines work with the general principle of combining air and fuel into an air-fuel mixture, that is sprayed into the combustion chamber and ignited through either compression, or a spark from the plugs themselves. In turn, this creates a power stroke through the piston and connecting rod, driving the crankshaft round on its cyclic journey, and ultimately turning the wheels through the connected transmission.

For the engine to be able to seal off the combustion chambers when combustion itself is occurring, the use of valves is necessary. The idea of this is to create a high-pressure environment for the ignition of the air-fuel mixture, to create power and torque, and all-in-all to perform successful combustion.

The valves themselves in most conventional four-stroke IC engines are ultimately controlled through rotation of the crankshaft. The crankshaft is connected to the valves through a number of pathways. The number of pathways is determined through the number and layout of cylinders that are present. This is also determined by the positioning of the valves about the cylinder as I shall go onto explain.

Firstly, taking an inline engine as an example (a number of cylinders all on the same axis), the crankshaft is often connected to two camshaft gears, positioned on either side of the cylinder head, in line with the valves in the head. The camshaft gears themselves are connected to the crankshaft via either a timing chain or timing belt, so the gears move in sync with the crankshaft.

Furthermore, the camshaft gears are directly attached to the camshafts themselves. Camshafts are exactly what they say on the tin – shafts made of steel and cast iron, with cams along the lengths of them. The egg-shaped cams (or ‘lobes’ otherwise known as) are positioned in different orientations all along the shaft for a very specific reason, being the fact that it controls valve opening and closing time within the cylinder.

As the crankshaft rotates, it also causes the timing belt or chain to begin its journey. In turn, this rotates the camshaft gears, and thus, the camshaft itself. As the shaft turns, the egg-shaped cam lobes hit the top of each valve and its corresponding spring. In doing so, the valve closes from its open position and depending on the current stroke within the engine, will either seal the cylinder for the combustion stroke or allow the other set of valves to open. The reason for this is due to the existence of the second camshaft.

Within most modern four-stroke IC engines, there exists four valves per cylinder, split into two for intake and two for exhaust. This is the general principle behind the workings of the system itself.

How does a four-stroke engine operate?

The workings of a four-stroke engine as are as follows - air is sucked in through the air intake which can either be:

Turbocharged
Supercharged
Pro-charged

These three options compress the air and allow artificial displacement, creating more power due to the presence of abundant oxygen – this is known as forced induction

The fourth option is Naturally Aspirated (NA), which allows air at atmospheric temperature and pressure into the engine instead of using a forced induction method.

The camshaft then rotates with the crankshaft, causing the egg-shaped cam lobes on the intake side to release pressure on the valves, and due to them being spring-actuated, the valve automatically opens when the cam lobe is not in contact with it. This allows air (or the air-fuel mixture depending on injection or mixing methods) to enter the combustion chamber when the piston has returned to Bottom Dead Center (BDC), which in effect is the bottom of the piston’s stroke.

As the piston rises again, the camshaft and the cam lobes also turn, putting pressure back on the valve to close it. This seals the combustion chamber off, and the piston rises back to Top Dead Center (TDC), which is the top of its stroke at the highest point of its rotational journey. As the piston ascends, it compresses the air-fuel mixture, but what happens next is dependent on the fuel and engine type.

If the fuel is diesel, the piston will compress the air-fuel mixture to a point at which it can be compressed no more, at extremely high pressure. The result of this in the chamber is that of auto-ignition, which causes the combustion of the mixture.

However, if the fuel being used is petrol, a different process takes place. As the mixture is compressed to its highest point, a spark plug is used to ignite the mixture instead of the diesel combustion process (auto-ignition through compression). The result of both processes is identical though, with combustion occurring, forcing the piston down to BDC on its power stroke.

When the piston has completed this stroke, it begins to rise again, and in doing so, the camshaft and cam lobes also rotate accordingly. The camshaft and lobes on the exhaust side release pressure on their corresponding valve, causing them to open. The piston continues to rise, and the valves open fully. In doing so, the spent gases are expelled through the exhaust valves and out of the engine through the headers and manifold.

The number of strokes in this sequence equates to that of the ‘four-stroke’ name – the first downwards stroke being the intake and injection stroke, the second stroke being the upwards compression and ignition stroke. After this, the third stroke is the power stroke, where the power from combustion forces the piston down, and finally the fourth stroke, which is the upwards exhaust stroke that releases the exhaust gases from the cylinder.

Overall, this is how a conventional four-stroke piston engine operates. However, there are obviously variations in the workings of different engines. A big variation that affects the general layout for engine heads is the positioning of the camshaft. The engine setup I described uses a DOHC setup, which stands for Dual Over-Head Cam, with two camshafts, one for intake and one for exhaust. There are most commonly four setups used in modern cars, SOHC (Single Over-Head Cam), OHV (Over-Head Valve), OHC (Over-Head Cam) and finally, DOHC (Dual Over-Head Cam, as previously mentioned). In most inline engines, these all work fairly similarly, just adjusting the positioning of the camshafts and the number of them, and often the number and orientation of cams on the shafts.

Diagram of a traditional DOHC engine setup

OHV engines are common with early muscle cars from the 1960’s and their iconic V8 blocks – muscle car being an American term for high-performance coupes, generally using rear-wheel drive and a large displacement V8 engine. For example, the Ford Mustang, Chevrolet Camaro, Chevrolet Corvette, Dodge Charger, Dodge Daytona, and Pontiac Firebird are all classified as ‘muscle cars’.

The idea of running a single camshaft inside the block greatly reduced weight. However, with this system, many pushrods, lifters and rocker arms (components connecting the valves and their springs to the single camshaft) are required to be able to activate and deactivate the valves through the return springs.

This means that the system is a lot less accurate for timing, and is difficult to be precisely adjusted at higher RPM’s (Revolutions Per Minute of the engine’s internal components) in comparison to more modern SOHC and DOHC engines. The reason for this is the increased levels of inertia from the number of parts actually in this specific valvetrain.

This OHV setup is now less desirable due to the complexity, efficiency, weight and cost of them, compared to the modern SOHC and DOHC engines, which are simply better than their historic counterparts, and have a greatly increased ability of tuning.

The idea of tuning is to be able to get the most out of the engine for its required use, for example:

For fuel efficiency
For emissions
For maximum power and/or torque

All of this is possible through adjustments of the existing camshafts by altering timing for fuel injection and/or spark timing. The overall point is that the camshaft is an extremely important asset for the influential movements of an engine’s workings; for fine-tuning those extra few horsepower and Newton-metres of torque out of the engine. They have the ability to open up the engine’s performance and capability to execute the task at hand.

Introducing Freevalve

Now, this is where Freevalve – Koenigsegg’s sister company - blow all existing camshaft and traditional setups out of the water. Freevalve has developed an electro-hydraulic-pneumatic system that entirely eradicates the need for a camshaft setup.

Their pneumatics system still uses valves for each cylinder to control the intake and exhaust flow, before, during and after each combustion cycle. However, the difference with this setup is that it is completely separate from the rest of the engine, not controlled by the crankshaft, camshaft (including cams), lifters, rocker arms, belts, or chains.

The pneumatically controlled valves on each cylinder are also entirely separate to each other, which is what makes this design so revolutionary. Due to the valves being separate and not connected via the means of a camshaft, they can all be controlled individually through the pneumatic system.

The fact of this independence dramatically changes the game of engine control and opens up a whole new world of performance, and the extraction of every last joule of energy that originates from the combustion process.

Diagrams of the Freevalve engine head setup and its pneumatic actuators (components that convert energy – usually in the form of compressed air - into mechanical motion) for each valve

In a conventionally controlled camshaft setup, the camshaft and cam lobes rotate together due to their connection, meaning that each cylinder will receive the same ignition and/or injection timing. However, with the independence of each valve, each cylinder in turn has the possibility of receiving its own timing. The advantage of this in our technologically developed world is that this is all controlled by the ECU (Electronic Control Unit).

This means that the ECU will automatically change the valve timing for each cylinder depending on the current requirements of driving and driving style. If more power is needed, a more aggressive valve strategy will be adopted by each pneumatic valve – credit to the ECU’s mind-boggling capabilities.

However, if smoother, cruise driving is required by the driver, the ECU may choose to relax the valve timing for efficiency within the engine. With this independent capability, comes even greater control over the engine. The valve timing can be adjusted to the point at which entire cylinders can be shut down for ultimate efficiency driving.

The general principle of this is that cruise motorway driving requires a lot less power than you’d expect to keep the vehicle at a constant velocity, and often a reduced activated cylinder number can still generate the necessary power to keep it there at that velocity.

Other advantages of this shutdown are huge boosts in emissions reduction and also highly reduced fuel consumption. As quoted from the Freevalve website:

"In test with a Qoros 1.6 liter 4 cylinder engine the Freevalve technology has proven: 17.2% standby/idle loss elimination and 15% fuel consumption reduction".

These are serious numbers in the game of engine development and for the future of our planet. With global warming becoming a growing concern in the modern world, reduced fuel consumption and emissions are highly sought after, and this technology can bring that into reality.

This is why this completely independent system is so unique and revolutionary. It allows for a plethora of different applications within the automotive sector, and also for industrial purposes with possible incorporation into many different sized generators and engines. These include everyday vehicles like cars, vans and lorries (benefitting them greatly for efficiency during long journeys of haulage), but also race cars and more extreme examples, such as usage in aircraft, and even marine vessels. In fact, the possibilities are huge as the system can be implemented with relative ease, which brings me onto the dimensions and physical structure of the pneumatic system.

The whole system is packaged neatly within an almost ‘flat-packed’ engine head, which in comparison to the regular head is a lot smaller, reducing the overall height of the engine. Not only this, but due to not needing belts and gears for driving the camshafts, a huge amount of space is saved at the front of the engine. This allows for engines to fit within smaller engine bays, reducing costs for materials and also emissions from production.

Having the engine head so much lower on top of the block also has advantages for the vehicle. When designing race cars such as open wheelers for the Formula series, the center of gravity is a huge factor when it comes to the drawing board. You want the center of gravity to be as low as possible within your vehicle, as this creates stability within the structure, allowing high speeds to be taken through corners that most other vehicles would have to slow down for. So when it comes to Freevalve, reducing the height of the engine with their pneumatic system really does have a dramatic impact, not only on engine performance, but the vehicles driving and handling capabilities too. So, what Freevalve are offering is not just complete control of the engine, but the overall performance from the vehicle.

Koenigsegg, that I have previously mentioned, have used this technology to great effect within their recent hybrid hypercar – the Koenigsegg Gemera, recently released on the 3rd of March 2020 (shown below).

The Koenigsegg Gemera

The Gemera is a four-seat hybrid beast with a combined 1700hp coming from its powertrain, which is rather special, to say the least. It utilises three motors at the rear of the car, two on the rear wheels, and the third lies on the crankshaft of the second half of the powertrain. Now, the second half is extremely revolutionary, and just so happens to incorporate the Freevalve technology I have prior described.

This technology is attached to a powerful three-cylinder two-litre engine. However, this engine is extremely special, as it produces over 600hp, whereas most three – cylinders on the road today produce anywhere from around 50hp to about 270hp in the new Toyota GR Yaris. However, these figures are nowhere near the insanity of Koenigsegg’s 600hp beast of an inline three-engine, aptly named the Tiny Friendly Giant (TFG for short).

Koenigsegg’s 600hp Tiny Friendly Giant in all its twin-turbocharged, Freevalve glory

The way Koenigsegg have achieved this is through a number of techniques. They have adopted an ingenious method of twin-turbocharging their engine, incorporating the Freevalve technology directly into the engine’s workings. Each cylinder has four valves controlled completely by the pneumatic actuators in the Freevalve engine head.

The turbo setup uses this to its advantage, with their twin-turbo setup, one turbo being considerably larger than the other. The doubling up of valves on each side has great usage within this engine, because at normal load during driving, or cruise driving, one exhaust valve can be closed, sending exhaust gases only into the smaller turbo, and only drawing air into the intake side of the smaller turbo also.

This allows for higher efficiency, but when necessary, extremely fast boost response, minimising boost lag (a delay between pedal to the metal and the turbo spooling for boost production). Moreover, the TFG runs the second, much larger turbo on the secondary valves in each cylinder. The idea of this is to be able to activate it when peak power is required, giving the Gemera an aggressive power and torque curve.

The turbo setup allows for a huge range of applications for driving, for cruising, or for taking it to the track, or drag strip. The combination of the TFG, Freevalve head and the turbo setup allows for more horsepower and torque numbers to be produced by a three-cylinder than ever before, just going to show how effective the Freevalve solution can be.

I quote Christian Von Koenigsegg:

“For the Qoros 1.6 liter 4 cylinder engine, torque increased by 47% and power increased by 45%”

This just goes to show how much performance can truly be extracted from engines previously using conventional setups. Sometimes, boundaries need to be pushed, and turning to unconventional methods just so happens to be the right way to go.

The overall idea here though is that the power and control of the TFG comes from the revolutionary Freevalve technology, able to fine-tune and control each cylinder and valve individually. It can literally adjust itself through the ECU, completely automated, ready for any situation the driver throws at it. Another huge advantage of Freevalve within the TFG is that the timing can be adjusted to accommodate for biofuel. This just proves another point, that it is extremely applicable in our ever-varying world, as climate change alters the way we must act to limit the damage it may cause to our habitats and lives as we know it. Freevalve and Koenigsegg are demonstrating that the engine is not yet dead, and can still operate even with changing times due to the usage of cleaner fuel, and still produce the necessary power and torque that is required, in a lot smaller package than previously possible.

These two revolutionary companies have the opportunity to change the automotive world forever, ultimately impacting the environmental world too. They can extract the ultimate and/or necessary performance from the engines and technology that they utilise, and can greatly improve the handling of the vehicle that the powertrain is mated to.

What about costs?

Currently, the technology within Freevalve is quite expensive, so will take time to become fully incorporated into society. However, according to Drivetribe, a spark-ignited engine with the Freevalve system attached is still technically cheaper than an entire diesel engine, showing that even now, it is not ridiculously priced. As time goes on, prices will drop further due to advancements in technology, suggesting that Freevalve will become a large part of the automotive world.

Also, the process to create the technology is relatively efficient in using raw materials, so is a fairly clean method in terms of the environment to actually produce it. Additionally, when the engine is in operation, the amount of savings that can be made from engine efficiency and fuel-saving will provide a quicker return on investment, offering a clean and cost-efficient (over time) direction for the automotive sector to head in.

Summary

Due to Freevalve and Koenigsegg’s ingenuity, I believe that the lifetime of the piston engine will be greatly extended, as it will be able to adapt to change and the oncoming challenges of life on this planet. Also, more performance can be obtained than ever before, pushing the very boundaries of the automotive universe. I leave you with a quote from Christian Von Koenigsegg himself:

“Every day we strive, and push, and learn, and adapt. And when you do that for twenty years with a great focus within the group, you can do pretty much anything”.

More photos of Koenigsegg’s new hypercar – the Gemera, featuring the new TFG and Freevalve technology