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Reciprocating Engines
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
Both piston speed and engine rotating speed should be considered in engine selection. Piston speed is commonly expressed in ft/s (or m/s), while rotational speed refers to crankshaft speed and is commonly expressed in rpm. While rotating speed is most commonly referred to when classifying engines, it does not take into consideration the size and piston stroke of an engine. A long-stroke engine with a low rotating speed may have a high piston speed. On the other hand, a high-speed, short-stroke engine may have a relatively low piston speed.
Compression-Ignition Engine Combustion
Published in Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong, Combustion Engineering, 2022
Kenneth M. Bryden, Kenneth W. Ragland, Song-Charng Kong
Diesel engines come in a wide range of sizes, from small-utility engines to enormous ship engines. Although the crank shaft speed ranges from 50 rpm for very large engines to 5,000 rpm for very small engines, the average piston speed does not vary nearly as much as the crank shaft speed. Small engines produce less torque than large engines, but, by operating at higher revolutions per minute, they improve power output per unit of cylinder volume. Table 12.1 shows examples of the wide range of sizes and power outputs produced.
Current-pressure-position triple-loop feedback control of electro-hydrostatic actuators for humanoid robots
Published in Advanced Robotics, 2018
Tianyi Ko, Hiroshi Kaminaga, Yoshihiko Nakamura
Hydra [12] is an adult size humanoid robot whose 40 joints are driven by electro-hydrostatic actuators. The full version has 130 kg weight and 180 cm height. It has 24 linear cylinders and 8 vane motors driven by 36 trochoid pumps. Each hand has 5 DoF driven by a cluster miniature EHA [19]. Most of the joints are driven by the standard actuator set: a combination of the double-rod linear cylinder with beam structure and the water-cooled trochoid pump with a reinforced structure. With the 5.3 MPa pump discharging pressure, the cylinder can generate 1500 N force. It has 50 mm stroke and the maximum piston speed is 200 mm/s. The total weight, with the electric motor, is 1220 g. The specification of the standard EHA is summarized in Table 1.