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The paper describes a completely new approach to fully variable valve actuation (FVVA), which allows almost unlimited continuously variable control of intake and exhaust valve opening and closing events, and duration without the use of a camshaft. DigitalAir replaces conventional poppet valves with horizontally actuated valves located directly above the combustion deck of the cylinder head, which open and close a number of slots connecting the cylinder with the intake and exhaust ports, Figure 1. The stroke of the valves to provide the full flow area is approximately 25% of the stroke of the equivalent poppet valve, thus allowing direct electrical actuation with very low power consumption. This design arrangement also avoids the risk of poppet valve to piston collision, or the need for cutouts in the piston crown, since the valves do not open into the cylinder. The paper will present analytical and experimental data which confirms that the proposed FVVA system can meet the basic performance requirements of modern GDI engines with respect to breathing characteristics across the speed range, throttleless operation at and above idle, opening and closing event optimization, cylinder deactivation, control of residual gas fraction / scavenging and exhaust thermal management. Analytical results were developed using GT-POWER Cycle Simulation and CONVERGE computational fluid dynamics (CFD). Cycle simulation was used to study the system level performance, such as full load capability and transient response, and in particular to quantify the fuel consumption benefits of throttleless operation. CFD was used to better understand the opportunities for in-cylinder charge motiontumble, swirl and turbulence. JP SCOPE Inc. has been running experimental engines with DigitalAir for several years and has successfully completed performance and durability tests. The mechanical and thermal design of the cylinder head, and the design of the actuator will be covered in Part 1 of this paper [1].

The increasing recognition of Plunger-Lift as a viable method for producing many wells, has brought a number of changes to the technology involved. The importance of proper plungerlift performance criteria (as reported in an earlier SPE paper) has been recognized and steps taken to incorporate this information into modern day control systems. This paper discusses the usage of plunger velocity in establishing operating cycles for gas wells and for oil wells. When used in conjunction with state of the art electronic microprocessors. the results are increased production, extended economic limits. less down-time, and many others. This has been proven to be the case in both conventional and slim-hole wells. Primary areas of discussion are:Relativity of plunger velocity insofar as efficiency is concerned.Standard approach historically taken to achieve maximum production.New software design that automates cycle changes while increasing production and reducing both man-hours and down time.Test results and case histories. Results, Observations and Conclusions: Significant production increases have been realized in the vast majority of wells produced via this method. Modest increases were realized on the remainder of wells tested. Optimization, by using plunger travel velocity has proven to be highly successful. Increases in excess of 100% realized on many gas wells. Reducing down-time, saving man-hours, increasing production rates, handling line pressure changes and generally eliminating the most common problems associated with plunger-lift are the result of this approach. Applications:Gas well dewatering, even for marginal producers. For both conventional and slim-hole wells.High GLR wells.Wells with high or fluctuating sales line pressures.