Abstract: A two-stage stiffness driveshaft includes a hollow cylinder having first and second ends and a hollow cylinder stiffness. An inner shaft having first and second ends and an inner shaft stiffness extends through the hollow cylinder. The inner shaft's first end and the hollow cylinder's first end are engaged via a rotational clearance fit. The inner shaft's second end is rotationally fixed to the hollow cylinder's second end to permit the inner shaft's first end to twist through a predetermined angle relative to the inner shaft's second end. The inner shaft's stiffness defines the driveshaft's first-stage stiffness, while the combined stiffness of the inner shaft and the hollow cylinder defines the driveshaft's second-stage stiffness. A damping element positioned between the inner shaft and the hollow cylinder controls variation in torque transmitted by the driveshaft and generates gradual transition between the first-stage stiffness and the second-stage stiffness.

Abstract: A two-stage stiffness driveshaft includes a hollow cylinder defined by a longitudinal axis, a first end, a distal second end, and a hollow cylinder stiffness. The driveshaft also includes an inner shaft extending through the hollow cylinder along the longitudinal axis and defined by a first end, a distal second end, and an inner shaft stiffness. The first end of the inner shaft is engaged with the first end of the hollow cylinder via a rotational clearance fit. The second end of the inner shaft is rotationally fixed to the second end of the hollow cylinder such that the first end of the inner shaft can twist to a predetermined angle with respect to the second end of the inner shaft. The inner shaft stiffness defines a first-stage stiffness of the driveshaft, and the inner shaft stiffness and the hollow cylinder stiffness together define a second-stage stiffness of the driveshaft.

Abstract: A two-stage stiffness driveshaft includes a hollow cylinder defined by a longitudinal axis, a first end, a distal second end, and a hollow cylinder stiffness. The driveshaft also includes an inner shaft extending through the hollow cylinder along the longitudinal axis and defined by a first end, a distal second end, and an inner shaft stiffness. The first end of the inner shaft is engaged with the first end of the hollow cylinder via a rotational clearance fit. The second end of the inner shaft is rotationally fixed to the second end of the hollow cylinder such that the first end of the inner shaft can twist to a predetermined angle with respect to the second end of the inner shaft. The inner shaft stiffness defines a first-stage stiffness of the driveshaft, and the inner shaft stiffness and the hollow cylinder stiffness together define a second-stage stiffness of the driveshaft.

Abstract: A system according to the principles of the present disclosure includes a vibration level module and an engine operation control module. The vibration level module estimates a first level of vibration in a vehicle due to contact between tires of the vehicle and a road surface as the vehicle travels over the road surface. The vibration level module estimates a second level of vibration in the vehicle due to an engine in the vehicle. The engine operation control module selectively adjusts at least one of a speed of the engine and a load on the engine when the second vibration level is less than the first vibration level.

Abstract: A system according to the principles of the present disclosure includes a vibration level module and an engine operation control module. The vibration level module estimates a first level of vibration in a vehicle due to contact between tires of the vehicle and a road surface as the vehicle travels over the road surface. The vibration level module estimates a second level of vibration in the vehicle due to an engine in the vehicle. The engine operation control module selectively adjusts at least one of a speed of the engine and a load on the engine when the second vibration level is less than the first vibration level.

Abstract: A method and system for initiating the oscillation of a crystal that controls a crystal oscillator by applying an initiating pulse to said crystal. The initiating pulse having a pulse width less than one half the periodicity of said crystal.

Abstract: A method of communication between a first transceiver having a first local oscillator set at a first frequency and a second transceiver having a second local oscillator set at a second frequency disclosed. The method includes transmitting a first signal at a first frequency from the first transceiver to the second transceiver, transmitting a second signal at the second frequency from the second transceiver to the first transceiver, and receiving the second signal at the first transceiver. The method further includes maintaining the first local oscillator at the first frequency and the second local oscillator at the second frequency during the transmitting of the first signal, during the receiving of the first signal, during the transmitting of the second signal, and during the receiving of the second signal.