Attached you will find the torque vs engine rpm and power vs engine rpm curves for an 'ideal engine' and also for a 'normal SI engine'.(adsbygoogle = window.adsbygoogle || []).push({});

1.(for the 1st ideal engine curve)Is it 'ideal' that the torque curve should decrease as the engine rpm increases? Why?

Does this mean that 'ideally' in a road, the traction force should decrease with increasing engine rpms ? I don't get theintuitive meaningas to why an 'ideal engine' would have curves like this.

Say, the vehicle is on the same gear and we increase the engine rpm by pressing the accelerator.

Then, in real life, the torque and traction force increase until a point where there is not more power for acceleration OR slip starts. But, in the ideal engine case, the vehicle would have reduced torque/traction force as you press the pedal more? How does this help?

By manipulating equations, I arrive at some understanding but its still vague:

I try to justify the reason why the torque curve is shaped like this: I try to arrive at a connect. between torque,traction force and engine rpm.

A.Speed equation : [itex]\omega_e=\frac{n_in_d*v_x}{R_x}[/itex]

B.Traction equation:[itex]T_e=\frac{R_wF_x}{\eta* n_in_d}[/itex]

Then equating the values for $n_in_d$, we get the relation between torque and traction force,

[itex]T_e=\frac{v_xF_x}{\eta\omega_e}[/itex]

where, [itex]\eta[/itex] is the driveline efficiency, [itex]\omega_e[/itex] is the engine rpm, [itex]F_x[/itex] is the driving force/traction force.

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# Interpretation of an ideal engine torque,power curves

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