Angular velocity/angular acceleration calculator, torque estimator, and combustion state estimator
First Claim
1. An angular velocity/angular acceleration calculator for a crankshaft in an internal combustion engine, the calculator comprising:
- a crank angle detection device that detects a crank angle in said internal combustion engine and a time at said crank angle;
a crank angle correction device that corrects, in accordance with a predetermined crank angle pitch, said crank angle and said time both detected by said crank angle detection device; and
an angular velocity/angular acceleration calculation device that calculates an angular velocity and an angular acceleration of said crankshaft by converting a function of said time with respect to said crank angle corrected by said crank angle correction device so as to be regarded as a periodic function, and utilizing a derivative of said converted function with respect to said crank angle obtained from a discrete Fourier transform of said converted function.
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Abstract
An angular velocity/angular acceleration calculator of the crankshaft in an internal combustion engine includes a crank angle detection device, a crank angle correction device, and an angular velocity/angular acceleration calculation device. The crank angle detection device detects a crank angle in the internal combustion engine and a time at the crank angle. The crank angle correction device corrects the crank angle and the time thus detected to an equiangular crank angle and a time corresponding thereto. The angular velocity/angular acceleration calculation device calculates an angular velocity and an angular acceleration of the crankshaft by converting a function of the time with respect to the crank angle that are corrected by the crank angle correction device so as to be regarded as a periodic function, and utilizing the discrete Fourier transform of the converted function.
28 Citations
9 Claims
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1. An angular velocity/angular acceleration calculator for a crankshaft in an internal combustion engine, the calculator comprising:
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a crank angle detection device that detects a crank angle in said internal combustion engine and a time at said crank angle; a crank angle correction device that corrects, in accordance with a predetermined crank angle pitch, said crank angle and said time both detected by said crank angle detection device; and an angular velocity/angular acceleration calculation device that calculates an angular velocity and an angular acceleration of said crankshaft by converting a function of said time with respect to said crank angle corrected by said crank angle correction device so as to be regarded as a periodic function, and utilizing a derivative of said converted function with respect to said crank angle obtained from a discrete Fourier transform of said converted function. - View Dependent Claims (2, 3)
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4. A torque estimator in an internal combustion engine, the estimator comprising:
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an angular velocity/angular acceleration calculator for a crankshaft in the internal combustion engine, the calculator including, a crank angle detection device that detects a crank angle in said internal combustion engine and a time at said crank angle, a crank angle correction device that corrects, in accordance with a predetermined crank angle pitch, said crank angle and said time both detected by said crank angle detection device, and an angular velocity/angular acceleration calculation device that calculates an angular velocity and an angular acceleration of said crankshaft by converting a function of said time with respect to said crank angle corrected by said crank angle correction device so as to be regarded as a periodic function, and utilizing a derivative of said converted function with respect to said crank angle obtained from a discrete Fourier transform of said converted function; and an axial torque calculation device that calculates an axial torque of said crankshaft by applying said crank angle corrected by said crank angle correction device and said angular velocity and said angular acceleration of said crankshaft calculated by said angular velocity/angular acceleration calculator to an equation of motion for a system including a piston, a connecting rod, and said crank in said internal combustion engine. - View Dependent Claims (5, 6, 7, 8)
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9. A combustion state estimator that estimates a combustion state of an internal combustion engine, the internal combustion engine including a crankshaft, said estimator comprising:
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an estimator unit that estimates the combustion state of the internal combustion engine in accordance with at least one of an angular acceleration calculated by an angular velocity/angular acceleration calculator, a gas pressure torque calculated by a gas pressure torque calculation device, and a gas pressure work calculated by a gas pressure work calculation device, wherein said angular velocity/angular acceleration calculator includes, a crank angle detection device that detects a crank angle in said internal combustion engine and a time at said crank angle, a crank angle correction device that corrects, in accordance with a predetermined crank angle pitch, said crank angle and said time both detected by said crank angle detection device, and an angular velocity/angular acceleration calculation device that calculates an angular velocity and the angular acceleration of said crankshaft by converting a function of said time with respect to said crank angle corrected by said crank angle correction device so as to be regarded as a periodic function, and utilizing a derivative of said converted function with respect to said crank angle obtained from a discrete Fourier transform of said converted function, said gas pressure torque calculation device includes, said angular velocity/angular acceleration calculator, an axial torque calculation device that calculates an axial torque of said crankshaft by applying said crank angle corrected by said crank angle correction device and said angular velocity and said angular acceleration of said crankshaft calculated by said angular velocity/angular acceleration calculator to an equation of motion for a system including a piston, a connecting rod, and said crank in said internal combustion engine, an external torque estimation device that estimates an external torque according to the torque obtained in accordance with said equation of motion at a peculiar crank angle allowing said equation of motion to be regarded as a relational equation among a moment of inertia, an angular acceleration, and the external torque around the crankshaft, and a gas pressure torque calculation device that calculates the gas pressure torque by subtracting said external torque estimated by said external torque estimation device from said axial torque calculated by said axial torque calculation device, and said gas pressure work calculation device includes, said gas pressure torque calculation device, and a gas pressure work calculation device that calculates the gas pressure work by integrating said gas pressure torque calculated by said gas pressure torque calculation device in a predetermined range of said crank angle.
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Specification