Torque measurement circuit and method

Claim 1

A torque measurement circuit for an internal combustion engine of the four cylinder, two-cycle type which accounts for inertia forces due to the mass of the pistons and connecting rods, said circuit comprising: pick-up means having an input indicative of the angular displacement of the crankshaft in an internal combustion engine from top dead-center position for generating a first signal directly proportional to the rotational speed of the crankshaft, said first signal having a portion indicative of when the piston is at top dead-center position; first circuit means responsive to said first signal proportional to the rotational speed for generating a second signal directly proportional to the engine's instantaneous rotational velocity; second circuit means responsive to said portion of said first signal indicative of when the piston is at top dead-center position for generating a sine wave signal at twice the angular displacement of the crankshaft; third circuit means also responsive to said portion of said first signal for generating a third signal directly proportional to the engine's average angular velocity; fourth circuit means for differentiating said second signal to generate a fourth signal directly proportional to angular acceleration; fifth circuit means responsive to said sine wave signal for phase shifting said sine wave signal by 90 degrees for generating a cosine wave signal; sixth circuit means responsive to said fourth signal proportional to acceleration, sine wave signal, and cosine wave signal for generating fifth and sixth signal both representative of average torque due to pressures inside of the cylinders and of impulse torque due to the mass of the pistons and connecting rods; seventh circuit means responsive to said third signal for generating a seventh signal directly proportional to the square of the engine's average angular velocity; and eighth circuit means for combining said fifth and sixth signals from said sixth circuit means with said seventh signal from said seventh circuit means to produce a resultant output signal proportional to the average torque and independent of the engine's speed with the effects of inertia forces being cancelled.

Claim 20

A method for measuring torque of an internal combustion engine of the four cylinder, two-cycle type which accounts for inertia forces due to the mass of the pistons and connecting rods, said method comprising the steps of: generating a first signal directly proportional to the rotational speed of the crankshaft of an internal combustion engine, said first signal having a portion indicative of when the piston is at top dead-center position; generating a second signal directly proportional to the engine's instantaneous rotational velocity in response to the first signal; initiating a sine wave signal at twice the angular displacement of the crankshaft when the piston is at top dead-center position in response to the portion of the first signal; generating a third signal directly proportional to the engine's average angular velocity in response to the portion of the first signal; differentiating the second signal to generate a fourth signal directly proportional to the angular acceleration or torque of the engine; phase shifting the sine wave signal by 90 degrees for generating a cosine wave signal; generating from the fourth signal proportional to torque, the sine wave signal and the cosine wave signal fifth and sixth signals both representative of average torque due to pressures inside of the cylinders and of impulse torque due to a mass of the pistons and connecting rods; generating a seventh signal directly proportional to the square of the engine's average angular velocity in response to the third signal; and summing the fifth and sixth signals with the seventh signal to produce a resultant output signal proportional to the average torque and independent of the engine's speed with the effects of the inertia forces being cancelled.

Claim 21

A method for measuring torque of an internal combustion engine of the four cylinder, two-cycle type which accounts for inertia forces due to the mass of the pistons and connecting rods, said method comprising the steps of: generating a first signal directly proportional to the rotational speed of the crankshaft of an internal combustion engine, said first signal having a portion indicative of when the piston is at top dead-center position; generating a second signal directly proportional to the engine's instantaneous rotational velocity in response to the first signal; initiating a sine wave signal at twice the angular displacement of the crankshaft when the piston is at top dead-center position in response to the portion of the first signal; generating a third signal directly proportional to the engine's average angular velocity in response to the portion of the first signal; differentiating the second signal to generate a fourth signal directly proportional to the angular acceleration or torque of the engine; phase shifting the sine wave signal by 90 degrees for generating a cosine wave signal; generating from the fourth signal proportional to torque, the sine wave signal and the cosine wave signal fifth and sixth signals both representative of average torque due to pressures inside of the cylinders and of impulse torque due to a mass of the pistons and connecting rods; generating a seventh signal directly proportional to the square of the engine's average angular velocity in response to the third signal; and summing the fifth and sixth signals with the seventh signal to produce a resultant output signal proportional to the average torque and independent of the engine's speed with the effects of the inertia forces being cancelled.

Claim 22

A method for measuring torque of an internal combustion engine, said method comprising the steps of: generating a signal directly proportional to the rotational speed of the cranshaft of an internal combustion engine; generating a sine wave signal at twice the angular displacement of the crankshaft; generating a signal directly proportional to the angular velocity of the crankshaft; differentiating the signal proportional to the rotational speed to provide a signal directly proportional to torque variations; phase shifting the sine wave signal by 90 degrees to produce a cosine wave signal; squaring the signal proportional to the angular velocity to produce a signal directly proportional to the square of the angular velocity; synchronously detecting the torque signal with the sine and cosine wave signals to produce a synchronous detection signal; and summing the synchronous detection signal with the signal proportional to the square of the angular velocity to produce a resultant output signal directly proportional to average torque and independent of speed.

Claim 23

A method for measuring torque of an internal combustion engine, said method comprising the steps of: generating a signal directly proportional to the rotational speed of the cranshaft of an internal combustion engine; generating a sine wave signal at twice the angular displacement of the crankshaft; generating a signal directly proportional to the angular velocity of the crankshaft; differentiating the signal proportional to the rotational speed to provide a signal directly proportional to torque variations; phase shifting the sine wave signal by 90 degrees to produce a cosine wave signal; squaring the signal proportional to the angular velocity to produce a signal directly proportional to the square of the angular velocity; synchronously detecting the torque signal with the sine and cosine wave signals to produce a synchronous detection signal; and summing the synchronous detection signal with the signal proportional to the square of the angular velocity to produce a resultant output signal directly proportional to average torque and independent of speed.