LaunchPoint Technologies is completing Phase II of a Small Business Innovation Research (SBIR) grant from the National Science Foundation (NSF) to design and test an electromechanical valve actuator. The technology (which is similar to the one presented by Cargine recently) enables reliable and cost-effective variable valve timing in camless internal combustion engines. According to Brian Paden, lead designer on the team, “Variable valve timing is an exciting technology that will open the door to the next generation of fuel-efficient internal combustion engines. LaunchPoint’s design enables continuous variability in the phase and dwell of the engine valve.” The first generation valve design supports operation over 6500 rpm when the controller is set for a 2.3 msec full transition across an 8 mm lift. The 10%-90% transition time for this controller setting is just 1.35 ms.
Idling engine (left) and high rpm conditions (right)
Although desirable for its demonstrated improvements in fuel-efficiency, torque, and emissions, variable valve timing has remained an elusive technology. Currently, available variable valve timing mechanisms are either too costly to implement on conventional vehicles or far less effective and robust than desired. The goal of the proposed project has been to demonstrate a compact, linear-motion actuator capable of driving a typical engine valve.
The advantage of LaunchPoint’s technology lies in the high-speed mechanism that recovers the valve’s kinetic energy at the end of each transition from open to closed and vice versa. The stored energy is then released to accelerate the valve on the next transition while also ensuring a soft landing. The low-power electromechanical actuator is used only to “throw” or “catch” the valve at the beginning or the end of the stroke.
Variable valve timing technology has demonstrated a fuel efficiency improvement of up to 20 %, torque improvement of 5 to 13 %, emission reductions of up to 10 % in hydrocarbons, and 40 to 60 % in NOx for conventional spark ignition (SI) and compression ignition engines. The demonstrated improvements are even more dramatic for innovative Homogeneous Charge Compression Ignition (HCCI) engines and Compressed Air Hybrid engines. For example, the NOx reduction is predicted to be two orders of magnitude lower in comparison to a conventional SI engine with almost zero particulate matter emissions.
Valves of this type can be applied to a wide variety of internal combustion engines. An electromechanical valve actuator eliminates the numerous engine components required for a typical camshaft drive, in turn, decreasing manufacturing and maintenance costs and increasing reliability. Such valves can be designed into new engines and retrofitted to existing engines. The widespread adoption of these valves would substantially decrease petroleum usage and the associated production of greenhouse gases and air pollution, while also promoting energy independence.
