LaunchPoint Technologies Inc. (LaunchPoint) has recently completed testing a new version of its variable valve timing (VVT) electromechanical valve actuator (EVA) for internal combustion engines. The new design reduces power consumption by more than 50% compared to the previous design and thus far has exceeded 1 million cycles of endurance testing. Funding was provided by the National Science Foundation (NSF) as part of a recently completed SBIR Phase II grant. Additional funding was provided by the United States Marine Corps (USMC) as part of an SBIR Phase I grant.
VVT EVA systems can provide improvements in engine fuel-efficiency, torque, and emissions, but are not widely used because until now the technology has been too expensive and has not met automaker’s performance targets. LaunchPoint’s electromechanical VVT system incorporates a novel energy storage mechanism that enables a reliable high performance and cost-effective actuator. With the use of a microcontroller, the system is able to continuously and independently vary the valve duration and phase based on any operating conditions available to the controller such as engine speed and load.
Electromechanical Valve Actuator Prototype Fabricated for the Project
Two prototype actuators were designed and built for the NSF Phase II grant. The actuators were tested on a lab bench and on a Rotax 500cc one-cylinder engine with a modified head. Videos of valve implementation in lab bench and test-engine experiments were recorded to demonstrate operation. In order to properly characterize the valve transitions, more than 500 datasets were recorded and processed to determine the switch times, landing velocities, and energy consumption (the switch time is defined using a standard industry definition of 0.7 mm – 0.7 mm; the time it takes to switch from within 0.7 mm of the open and closed positions). By developing an online adaptive control strategy we were able to maintain repeatable and reliable system performance with the following specifications: 1.63 - 3.82 ms switch times with 0.01 - 0.07 m/s landing velocity and 1.33 – 3.15 J energy consumption per switch. The precise system performance is dependent on the actuator configuration and how the control system is set up and tuned. At 5000 RPM this corresponds to an average power consumption of 116 W when the system is tuned for minimum power. Further improvements in performance to decrease the switch time, landing velocity, and switch energy will be realized with more controller development.
After the system performance was characterized, an endurance test was performed to evaluate the durability of the system. After 1 million cycles – corresponding to 2 million engine revolutions – the system was still functioning well and had minimal signs of wear. The durability target is to reach the equivalent of 500 to 600 million engine revolutions (250 to 300 million cycles) required for an automotive application.
Overall we achieved all of the proposed objectives and exceeded the performance goals of the Phase II grant. Further testing is required to determine the variation in the system performance over the life of the mechanism, and the overall durability and fatigue life of the mechanical components. LaunchPoint is currently seeking strategic partners and investors to bring this technology to market.
About LaunchPoint Technologies:
LaunchPoint Technologies Inc. is an engineering services and design firm that specializes in technology and product development. We have extensive experience in motor/generator design and development, medical device design and development, and maglev technologies. Our staff includes product and system designers, physicists, and engineers from a wide array of disciplines. As 'Venture Engineers' we invest our engineering expertise in proof-of-concept modeling and prototype design, secure IP, and assist with grant-writing and/or venture capital solicitation. For more information, please visit our website at launchpnt.com, or call 805-683-9659805-683-9659, ext. 207.
*This material is based upon work supported by the National Science Foundation under Grant IIP-1058556 and the United States Marine Corps under Grant M67854-14C-6525. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the United States Marine Corps.