| 摘要 |
1,124,701. Measuring torque of an I. C . engine. DRESSER INDUSTRIES, Inc. Oct. 20, 1965 [Dec. 2, 1964], No.44493/65. Heading G1N. [Also in Division G3] The torque developed by an I. C. engine is determined by measuring electrically the mean pressure developed in the cylinders, and subtracting from the signal that part which varies with speed, the remainder being directly proportional to torque. As shown (Fig. 1) a continuously running I. C. engine 10 drives a compressor pump 11. Each cylinder, e.g. 13, of the engine is supplied at its upper end with a long, thin tube 31 connected to a pressure transducer 36. The tube has a long time constant to gas flow and acts as a pressure averaging device. The pressure signals from all the cylinders C1 - C8 (Fig. 4) obtained from the individual transducers T1 - T8 are summed across a resistor 51 to give a signal e, representing the mean time pressure of the I. C. engine. A signal e 2 proportional to speed is supplied by a tachogenerator 55, and a predetermined proportion Ke 2 , obtained from potentiometer 58, is subtracted from e, to give a torque signal e 3 . Practical methods of adjusting the slider of potentiometer 58 to obtain the factor K are described. The torque signal e 3 is amplified at 63 and indicated on meter 62, an adjustable feedback resistor 65 being used to obtain a reading of 100% when the engine is operating at a selected torque, e.g. the rated torque. The same reading may be obtained at other predetermined torques by introducing selected proportions of an auxiliary voltage E 3 into the input circuit of amplifier 63, by switches 71a - 71f. The 100% torque value selected may be maintained constant by opening or closing clearance pockets on the compressor, thereby varying its volumetric efficiency, effected automatically by switch contacts 75, 76 on to meter 62, located on opposite sides of the 100% mark. The switches are incorporated in a relay circuit Fig. 5 (not shown), and control four way valves 87, 88, 89 for power cylinders 26b, 27b, 28b determining the open or close conditions of clearance pockets 26, 27, 28. |
