Picture from: http://www.freevalve.com/
Fuel efficiency and power have long been key areas of automotive development. Recently the high profile advances in this area have related to hybrid powertrains and a move to all electric vehicles. New developments in these areas regularly feature in new patent filing figures. A significant new development for a well-established technology like the internal combustion engine is less common and therefore exciting to see. In this case, it has come with help from an unusual source.
Christian von Koenigsegg is probably better known as the founder of Koenigsegg Automotive, which has been building some of the world’s most spectacular cars since 1994. Koenigsegg cars have always included advanced technology, for example the Agera R featured hollow, one piece, carbon fibre wheels. Now a company called FreeValve, in which Koenigsegg took an interest shortly after it was established (back when it was called Cargine Engineering), is producing an engine with no camshafts.
In a typical engine the crankshaft, which is driven by the pistons, is linked to one or more camshafts by a cambelt, or timing chain. The camshaft includes a plurality of lobes which, as the camshaft rotates, interact with the engine valves to cause them to open and close against a spring bias. The mechanical link between the crankshaft and the camshaft(s) ensures that the timing of the opening and closing of valves is coordinated with the movement of the pistons. This is a simple and generally reliable system, but there is not a great deal of flexibility. This lack of flexibility makes it impossible to optimise the valve timing for different engine speeds and operating conditions, and the setup is typically a compromise. There is also a significant power requirement for driving a camshaft and overcoming the associated friction losses.
The idea of removing the camshaft(s) and avoiding such issues is not new, with the likes of Valeo and, separately, a collaboration between Lotus Engineering and Eaton investigating the possibilities. The Valeo version used electro-magnetic actuators in place of camshafts to operate the engine’s valves, while the Lotus/Eaton system focussed on electro-hydraulic actuation.
In the FreeValve system each engine valve is individually opened by providing an electrical signal to a solenoid. A combination of air and hydraulic pressure is used to stabilize the opening valve, damping any oscillations from the solenoid. When the electrical signal is removed from the solenoid, the hydraulic pressure causes it to close. It appears that the valve actuator is the key to making this new technology a commercially viable option.
Removing the mechanical interaction between a cam and the valves allows greater control over the opening and closing of each valve. The air and hydraulic pressure in the actuator can be used to determine how wide each valve opens, and can also control the speed of valve movement. This control can improve fuel efficiency for the engine in a variety of conditions. The lack of a camshaft and associated hardware can make the engine smaller and lighter, and it also reduces the number of moving parts, which reduces friction.
In 2016 an engine (named Qamfree) incorporating FreeValve technology was installed in a Qoros 3 car and unveiled at the Beijing motor show. Qoros claimed that the modified 1.6L turbocharged engine was able to achieve a 47% increase in power output to 230 hp; a 45% increase in torque, to 236 lb.-ft.; and a 15% reduction in fuel consumption with the FreeValve technology.
The complete control over the valve movement means that the operation of the engine can be optimised for current operating conditions, rather than having to rely on a compromise provided by the fixed shape of a cam lobe. This could help to provide greater fuel efficiency in general use, or more power when required. The accurate control also provides advantages as some components, other than camshafts can be removed as a result. By carefully controlling the exhaust valves it is possible to heat an exhaust catalyst more quickly than normally possible so it works efficiently more quickly and this can avoid the need for a pre-catalytic converter. Also, the degree of intake valve opening can also be used instead of a traditional throttle meaning another part can be omitted and throttle response improved.
However, it is when the technology is coupled with forced induction, such as turbocharging, that more unexpected advantages become apparent. For example, in a FreeValve engine with two exhaust valves per cylinder it is possible to actuate them independently of one another. One exhaust port can connect to a turbocharger, while the other passes straight to the exhaust. This can provide the necessary control over turbo actuation without the need for a wastegate.
The valve actuator used in the Qoros 3 car was the sixth generation of actuator developed by FreeValve and represents over a decade of testing and development. The constant development process has resulted in many improvements and FreeValve says that it now has over 15 patent families protecting those innovations and IP generation remains an important commercial goal for the company. These patent families focus on various aspects of the technology including several for the actuator itself (such as WO2013/058704 & WO2016/167715)and methods of determining the relative positions of elements (such as WO2015/094110), but also include applications of the technology, such as combustion engines and engine braking methods (WO2016/060605). It is that IP protection that allows the company to exploit its innovations with third parties without having to rely solely on contractual restrictions and confidentiality clauses.
As electronic control and actuation becomes ever more reliable it is natural for engines to evolve. Over the years fuel injection has replaced carburettors and electronic ignition has replaced distributors and magnetos. Each time the internal combustion engine evolved it has been become more powerful, more useable and more efficient. The FreeValve engine potentially represents another such step forward. Each year millions of engines are produced in which the engine valves are installed under the control of camshafts. FreeValve technology could change that. Although a FreeValve engine has not yet featured in a Koenigsegg car, it does seem to be on the cards.
If you would like to discuss the above, or if you have an automotive innovation that you would like to protect, please contact one of attorneys from A.A. Thornton’s Automotive and Aerospace Sector Group.