The purpose of the present invention is to provide a test piece characteristic estimation method capable of quickly measuring the moment of inertia of a test piece while taking loss resulting from rotational friction of the test piece into consideration. This test piece characteristic estimation method is provided with a step (S1) for measuring a first transfer function G1 from a torque current command for a dynamometer to output from a shaft torque sensor by vibrationally operating the dynamometer, a step (S2) for measuring a second transfer function G2 from the torque current command to the output of a dynamo rotation speed sensor by vibrationally operating the dynamometer, and steps (S3 and S4) for calculating the value of a ratio obtained by dividing the second transfer function G2 by the first transfer function G1 at a prescribed measurement frequency .sub.k and using the ratio value to calculate a moment of inertia Jeg and a rotational friction Ceg.

An actual gear ratio change amount (Gr) is calculated by subtracting a pre-shift gear ratio (Gb) from an actual gear ratio (Gr). A gear ratio (G) is calculated by multiplying the actual gear ratio change amount (Gr) by a predetermined coefficient (C) and adding the product value to the pre-shift gear ratio (Gb). When the shift is an upshift, the gear ratio (G) is compared with aa target gear shift ratio (Ga), and the greater value is set as a virtual gear ratio (Gv). When the shift is a downshift, then the gear ratio (G) is compared with the target gear ratio (Ga) and the smaller value is set as the virtual gear ratio (Gv). A virtual input shaft rotational speed (Nv) is calculated by first dividing the actual gear ratio (Gr) by the virtual gear ratio (Gv) to obtain a quotient and by dividing the actual input shift rotational speed (Nr) by that quotient. A slip amount (S) is calculated by subtracting the actual input shaft rotational speed (Nr) of the automatic transmission (3) from the engine rotational speed (Ne). Finally, the engine rotational speed for display (Nd) is calculated by adding the slip amount (S) to the virtual input shaft rotational speed (Nv).

A target reaching rotational speed set during a torque phase is set to a value higher than an actual engine rotational speed, the value being higher as one of a vehicle acceleration and an engine rotational speed gradient is larger. That is, as the acceleration is steeper, the target reaching rotational speed is set to a value closer to an upper limit rotational speed or rotational speeds proximate thereto. Thus, a display rotational speed displayed on a tachometer at the end of the torque phase becomes high rotational speed. Accordingly, there is provided a display control device for a vehicle that enables a driver to feel the use of engine performance to the limit.

The application discloses a control device and a control method for an engine. The control device includes an electronic control unit configured to execute a stop-and-start control of automatically stopping the engine when a predetermined automatic stop condition is established and automatically restarting the engine when a predetermined automatic-restart condition is established during the automatic stop of the engine, and in a case where the automatic-restart condition is established during fuel cut-off according to the automatic stop of the engine, prohibit detection of the toothless part based on the pulse signal output from the crank angle sensor, for a period until the crankshaft is rotated by a predetermined crank angle or more after the automatic-restart condition is established.

In one embodiment, one or more tangible, non-transitory computer-readable media stores instructions. The instructions, when executed by one or more processors, are configured to receive engine rotation timing event signals for one or more components of the engine and vibration signals indicative of movement of the one or more components, to synchronize the engine rotation timing event signals and the vibration signals to generate synchronized vibration signals, to determine whether a fault exists by comparing the synchronized vibration signals to vibration signatures, and to generate a graphical user interface (GUI) that depicts the synchronized vibration signals at angular positions of the one or more components in relation to time as the one or more components rotate during operation of the engine.

A control apparatus for an internal combustion engine (i) acquires a rotational speed signal correlated with a rotational speed of the internal combustion engine, (ii) extracts, from the acquired rotational speed signal, at least first-order and lower-order than the first-order components of the rotational speed signal, (iii) extracts, from the acquired rotational speed signal, at least an n-th-order component of the rotational speed signal, (iv) determines that no disturbance has occurred when a first-order parameter regarding a magnitude of an amplitude of the extracted first-order and lower-order than the first-order components is smaller than a first threshold, and (v) determines that a disturbance has occurred when the first-order parameter is equal to or larger than the first threshold and an n-th-order parameter regarding an amplitude of the extracted n-th-order component is equal to or larger than a second threshold.

Provided are a deterioration diagnosis device and deterioration diagnosis method that make it possible to carry out accurate deterioration diagnosis that takes into consideration not only vibration quantity but also other vibration factors such as vibration cycle. This deterioration diagnosis device is provided separately from or so as to be integrated with an electric motor control device comprising a power converter for outputting power for driving an electric motor connected to a device to be driven, a position controller for outputting a speed command value corresponding to the deviation between a position command value and an electric motor position detection value, a speed controller for outputting a torque current command value corresponding to the deviation between the speed command value and an electric motor speed detection value, and a current controller for adjusting the output current of the power converter according to the deviation between the torque current command value and a detection value for the torque current supplied to the electric motor. The deterioration diagnosis device comprises a deterioration diagnosis unit for carrying out electric motor deterioration diagnosis corresponding to electric motor driving information and a vibration information storage device for storing the diagnosis results of the deterioration diagnosis unit. The deterioration diagnosis unit stores a plurality of types of information relating to the electric motor vibration state that have been calculated from the driving information in the vibration information storage device and determines that vibration has occurred if the information relating to the vibration state of the electric motor is larger than a prescribed threshold.

The present teaching aims to provide: a cam angle sensor fault diagnosis apparatus for straddled vehicle, capable of detecting a fault of a cam angle sensor installed in a straddled vehicle and guessing a fault place; an engine system; and a straddled vehicle. A cam angle sensor fault diagnosis apparatus for straddled vehicle includes: a cam signal receiving unit connected to a signal output line through which a cam angle sensor outputs a cam signal in accordance with the rotation angle, the cam signal receiving unit being configured to receive a cam signal via the signal output line; a state determination unit that determines one or two fault states of the cam angle sensor from a disconnection state, a power supply fault state, and a ground fault state, distinguishably from the other fault states, in accordance with a signal level of a cam signal received by the cam signal receiving unit; and a signal output unit that outputs a fault signal representing the one or two fault states determined by the state determination unit, in such a manner that the fault signal representing the one or two fault states is different from a fault signal representing the other fault states.

An actual gear ratio change amount (?Gr) is calculated by subtracting a pre-shift gear ratio (Gb) from an actual gear ratio (Gr). A gear ratio (G) is calculated by multiplying the actual gear ratio change amount (?Gr) by a predetermined coefficient (C) and adding the product value to the pre-shift gear ratio (Gb). When the shift is an upshift, the gear ratio (G) is compared with aa target gear shift ratio (Ga), and the greater value is set as a virtual gear ratio (Gv). When the shift is a downshift, then the gear ratio (G) is compared with the target gear ratio (Ga) and the smaller value is set as the virtual gear ratio (Gv). A virtual input shaft rotational speed (Nv) is calculated by first dividing the actual gear ratio (Gr) by the virtual gear ratio (Gv) to obtain a quotient and by dividing the actual input shift rotational speed (Nr) by that quotient. A slip amount (S) is calculated by subtracting the actual input shaft rotational speed (Nr) of the automatic transmission (3) from the engine rotational speed (Ne). Finally, the engine rotational speed for display (Nd) is calculated by adding the slip amount (S) to the virtual input shaft rotational speed (Nv).

The control apparatus for a vehicle includes a determination unit that determines whether or not a start condition is established, the start condition including when a torque converter is in a lockup state, and when the vehicle is in an accelerating state; and a display control unit that causes an acting number of rotations to be displayed on a tachometer instead of an actual number of rotations when it is determined by the determination unit that the start condition is established. The display control unit calculates the acting number of rotations based on a target value of an input number of rotations of a continuously variable transmission, and varies the acting number of rotations with a rate of change having an absolute value that is greater than an absolute value of a rate of change of the actual number of rotations upon an abrupt change in the target value.