“Racing engine mean piston speed has hardly increased in numeric value in fifty years”įig.1 Basic engine geometry equations, Eqns.1-4.įig.2 Power related engine equations, Eqns.5-8.Įngine. For racing engines, this limit parameter has hardly increased in numeric value in fifty years A further important mechanical design parameter is the mean piston speed (Cp), which is calculated by Eqn.4 in Fig.1. If required, the units of any data value in all equations are shown as subscripts. The calculation of thisīMEP by back-calculation using a re-arranged Eqn.6, because all otherīasic data is shown as Eqns.1-3 in Fig.1. The engine will have a bore to stroke ratio (Kbs). Output from the dynamometer data, you can calculate the value of the (Vsv) for each cylinder and a swept volume for the entire engine (Vtsv). Likely, having used Eqn.5 with the measured TORQUE to get the power However, and much moreĬylinder bore (B) and a stroke (S).
The brake mean effective pressure (BMEP). Or kilowatts) but if you want horsepower (bhp) instead then divide POWERkw by 0.7457 to get POWERbhp.Īlternatively, in Eqn.6 in Fig.2, one can compute the POWER usingĪn engine is a device with a number of cylinders (ncyl) each with a The computation of the POWERīased empiricism gives very effective guidance to engine design and The TORQUE is measuredĬomplex computer software, it should be a timely reminder that logic. To all designers, living daily with an often bewildering array ofĮngine produces a power output (POWER). Depending on the speed of rotation of the crankshaft (N) the Them to compare design concepts with numbers rather than argument. Theoretically agile, this paper should be welcome as it will permitĪ firing engine produces a turning moment at the crankshaft, the ToĮngineering graduates of yesteryear with fading memories of their undergraduate course in ‘ic engines’, and yet others perhaps less So I apologise for boring them and wasting their magazine space. Who are experts in engine design theory this paper could be ‘old hat’,Īt Castrol they will doubtless tell you that Castrol R was not easy to One would be hard put to call that a technological breakthrough To illuminate some, or to refresh the memory banks of all, into theĬylinder running on a synthetic lube oil has a mean piston speed of 25įundamentals of engine design that this paper is written. Today, a MotoGPĪs engineers design by numbers and not words it is in an attemptĮngine at peak power with its liquid-cooled and silicon-carbide plated Speed of 20 m/s at its engine speed for peak power. To numerically part with what is deemed to be confidential. Linered Norton Manx cylinder running on Castrol R had a mean piston
Then, an air-cooled and iron-ĭefence, this may be due to their information source refusing To replace numbers when explaining design concepts in their N technical magazines contributors will sometimes use wordsĪnd that fact reflects the gradual improvement of cylinder design and Blair & Associates discusses “Fundamentals and Empiricism in Engine Design” Gordon Blair, CBE, FREng, Senior Associate, Prof.
0 kommentar(er)
