ABSTRACT Stringent NOx and particulate emission constraints require high levels of exhaust gas recirculation. In this paper we model and analyze a Variable Valve Timing methodology that in steady-state achieves large levels of internal Exhaust Gas Recirculation (iEGR) or residual charge in Compression Ignition Direct Injection (CIDI) engines. Current external Exhaust Gas Recirculation (eEGR) te...

In this study, a nonlinear sliding-mode controller is designed for force tracking of a piezoelectric-hydraulic pump (PHP)-based actuation system, which is developed to replace the current electro-hydraulic actuation systems for automatic transmission (AT) friction elements, such as band brakes or clutches. By utilizing the PHP, one can eliminate the various hydraulic components (oil pump, regul...

Microfluidic chips are powerful tools for biochemical experiments. High speed and precise flow control can be achieved by using microvalves on a chip. Several types of microvalves that can be integrated into a microfluidic chip have been reported. Among them, gel microvalves have certain advantages over other valves because of their soft structure, which will contribute to prevent mechanical da...

Homogeneous charge compression ignition (HCCI) seems to be the most promising solution for gasoline engines in the light of future emissions regulations. This novel combustion technique allows for significant reduction of fuel consumption and engine-out NOX emissions at low and medium engine load/speed conditions. High heat release rate enables realization of the Otto cycle close to ideal, incr...

An automated, pre-programmed, multiplexed hydraulic valve actuator is described. The valve is membrane-based and normally open. In contrast to the membrane-based pneumatic valve, the hydraulic valve uses hydraulic liquid to exert the control pressure. The line pressure is controlled with a roller moving over a prefabricated topology. Multiple rollers, each traversing its own track, are assemble...

Integrated microvalves are needed for a broad range of semiconductor-processing-related applications. These include precision mass microflow controllers (laFCs) for dry etch systems, miniature gas chromatography systems for real-time monitoring, point-of-use semiconductor process reactant generators, and compact control systems for minienvironments. This paper reports a pneumatically actuated, ...

Robust and energy-efficient bipedal locomotion in robotics is still a challenging topic. In order to address issues in this field, we can take inspiration from nature, by studying human locomotion. The Spring-Loaded Inverted Pendulum (SLIP) model has shown to be a good model for this purpose. However, the human musculoskeletal system enables us to actively modulate leg stiffness, for example wh...

We report a method for addressing gas leakage in micromachined valves. The valves used for evaluating the proposed concept utilize a silicon valve seat that is bonded to a glass substrate and actuated by a piezoelectric stack, all of which are assembled within a ceramic package. The sealing method uses the capillary forces of a liquid sealant on the valve seat to reduce gas leakage below measur...

This paper presents a novel latchable phase-change microvalve that can potentially be used for flow gating in portable lab-on-a-chip systems here minimal energy consumption is desired. The microvalve innovatively exploits paraffin wax of low melting point, whose solid–liquid phase hanges allow the closing and opening of fluid flow through deformable microchannel ceiling. The latchable phase-cha...