Rise time

About: Rise time is a research topic. Over the lifetime, 4748 publications have been published within this topic receiving 47512 citations.

Throttle-control algorithm for improving engine response based on air-intake model and throttle-response model

Abstract: An electric-throttle-control actuator (ETC) is a device for control of the air mass flow to an engine cylinder. As adaptive-cruise-control and direct-fuel-injection systems become popular, the market of ETC has become larger. The ETC is controlled so that the engine torque follows the target value. Between the change of the control signal to the ETC and the engine-torque response, two delays exist-the delay in the throttle response and manifold filling. These delays must be compensated to improve the engine response. In this paper, a throttle-control algorithm for improving engine response is proposed. This algorithm compensates these two delays based on the response model. The response of the manifold pressure was experimented in two cases, when the ETC was controlled by a step input and when the throttle was controlled by the developed algorithm. The experimental results show that the rise time of the manifold pressure response decreased to one-tenth by the developed algorithm. Because the engine torque is proportional to the manifold pressure, it can be concluded that the torque response improved by compensating the two delay factors.

Compact Subnanosecond Pulse Generator Using Avalanche Transistors for Cell Electroperturbation Studies

Abstract: Research on the electroperturbation effects of ultrashort high field pulses in cancer cells requires subnanosecond rise time, high voltage pulses delivered to low impedance biological loads Here we present a compact solid-state pulse generator developed for this application The pulse is generated by switching a chain of avalanche transistors configured as a tapered transmission line from high voltage to ground The system features a built in 1400:1 capacitively compensated resistive voltage divider The divider, with a 3 dB point at 910 MHz, overcomes challenges in the direct measurement of the high frequency components of the output pulse The generator is capable of producing a 08 ns rise time, 13 ns wide, 11 kV pulse into a 50 Omega load at a maximum repetition rate of 200 kHz Techniques to implement physical layouting strategies to achieve subnanosecond rise times are outlined Problems faced in integrating the subnanosecond pulse generator with a biological load are discussed This pulse generator will be used in experiments aimed at electromanipulation of intracellular biomolecular structures

Picosecond semiconductor electronic switch controlled by optical means

Abstract: A microstrip transmission line on the surface of a photoconductive semiconductor medium has a small gap, thereby producing an open circuit between a microwave (or other electrical signal) source and a detector connected at opposite ends of the line. This gap is suddenly filled (and the microwave circuit thereby completed) by copious electrical charges which are generated in a semiconductor surface region across the gap, in response to a first pulse of optical radiation characterized by a picosecond rise time and by a wavelength which is substantially completely absorbed at the surface of the semiconductor medium. Accordingly, this first pulse produces a correspondingly sharp rise in the microwave energy (switch''''ON'''') reaching the detector. Within a few picoseconds thereafter (while the electrical charges due to the first pulse still persist), a second optical pulse, which is also characterized by a picosecond rise time but of a wavelength which is absorbed into the bulk of the semiconductor medium, is directed at the gap sufficient to increase significantly the conductance across the gap, thereby short-circuiting the microwave line to a ground plane on the opposed major surface of the semiconductor. Accordingly, the second pulse produces a correspondingly sharp decline (switch-'''' OFF'''') in the microwave energy reaching the detector from the microwave source.

Rise time and time‐dependent spark‐gap resistance in nitrogen and helium

Abstract: The rise time and time‐dependent spark‐gap resistance in nitrogen and helium were measured using a novel microwave method. Empirical formulas for spark‐gap resistance and rise time are proposed, with a maximum error, as compared to experimental results, of ±8%.