按曲柄转角记录展开示功图P=f(α),目前在内燃机上得到广泛的应用。它通常是采用示波器。用示波器取得的示功图不仅用来确定工作循环参数(P_c、P_z),而且也用来确定平均指示压力P_(?)。应用上述仪器时,正确确定与活塞上死点相应的曲轴位置对平均指示压力P测定的精确度具有实质性的影响[1、2]。示功罔中的上死点分静态标定和动态标定两种.上死点的静态标定可在非运行的柴油机上以大家熟知的方法进行,并按此位置装设上死点传感器。通常,在运行的柴油机上,活塞上死点位置由 According to the crank angle record expansion diagram P = f (α), is currently widely used in internal combustion engines. It usually uses an oscilloscope. Oscilloscope obtained using the dynamometer not only to determine the duty cycle parameters (P_c, P_z), but also to determine the average indicated pressure P_ (?). With the above instrument, correctly determining the crankshaft position corresponding to the top dead center of the piston has a substantial effect on the accuracy of the mean indicated pressure P [1,2]. There are two types of static top dead center and dynamic top dead center, the static top dead center can be calibrated on a non-operating diesel engine in a well-known manner and a top dead center sensor can be mounted at this position. Normally, on a running diesel engine, the piston has a top dead center position