Abstract: A method of controlling speed reduction ratio in a continuously variable speed transmission comprises the steps of setting a prescribed parameter corresponding an accelerator opening which is opened to a certain extent from a fully closed condition setting a reference engine speed corresponding to a parameter which represents a driver's intention of acceleration so as to increase as said parameter increase from said prescribed parameter when said parameter is in a range higher than said prescribed parameter setting said reference engine speed so as to increase as said parameter decreases from said prescribed parameter when said parameter is in a range lower than said prescribed parameter, and controlling said speed reduction ratio so that the engine speed coincides with said reference engine speed.

Abstract: A throttle control system for an internal combustion engine includes a first lever which is pivotable around a longitudinal axis of a throttle shaft depending upon movement of an accelerator pedal, and a second lever which extends radially from the throttle shaft and is fixed thereto. The system further includes a transmitting mechanism which mechanically transmits pivotal motion of the first lever to the second lever so that the angular position of a throttle valve fixed to the throttle shaft varies in response to depression of the accelerator pedal. The transmitting mechanism optionally changes the ratio of the pivotal angle of the first lever from that of the second lever, so as to change the relationship between the depression rate of the accelerator pedal and the opening angle of the throttle valve.

Abstract: A time-dependent engine output power characteristic curve for an engine output power to vary therealong to a target value which corresponds to an indication of intention of the driver for acceleration or deceleration (e.g., the amount of depression of the accelerator pedal) is established based on the difference between a target engine output power and an actual engine output power. Then, a target rate of change of the rotational speed of the engine and a target rate of change of an indication of an engine load are established so that the actual engine output power varies along the engine output power characteristic curve, and the throttle valve and the continuously variable transmission are controlled using the target rates thus established.

Abstract: A method controlling the speed reduction ratio for a continuously variable speed transmission comprises a running mode control method which is carried out when an accelerator opening is opened, an engine brake mode control method which is carried out when said accelerator opening is substantially closed and a transient control method which is carried out over a predetermined period of time when the control is shifted from a state under the engine brake mode control to a state under the running mode control.

Abstract: The speed reduction ratio of a continuously variable speed transmission is controlled by setting a reference engine speed according to a parameter representing a driver's intention of acceleration, such as the depression of an accelerator pedal, and controlling the speed reduction ratio so as to equalize the engine rotational speed with the reference engine speed. When the parameter is lowered such as by releasing the accelerator pedal, the process of controlling the speed reduction ratio due to a reduction in the reference engine speed caused by the reduction in the parameter is started after a certain time delay.

Abstract: A method of controlling a speed reduction ratio includes setting a reference engine speed in correspondence with an accelerator opening, measuring the atmospheric pressure, correcting the reference engine speed in correspondence with a change of the atmospheric pressure to compensate for a change in engine output power caused by the change of the atmospheric pressure, and controlling the speed reduction ratio so that the engine speed coincides with the corrected reference engine speed.

Abstract: A method of controlling clutch operation, for a vehicle having a transmission and clutch means comprises setting a reference capacity of said clutch means corresponding to a parameter representing vehicle speed and an accelerator opening representing the driver's intention of acceleration or deceleration: and controlling said degree of the engine power transmitted to the wheels by adjusting the capacity of said clutch means so as to coincide with said reference capacity.

Abstract: A duty ratio for operating a solenoid is determined by calculating a duty ratio in each of basic periods and determining an operational time for which the solenoid is to be operated within each of the basic periods, based on the calculated duty ratio. When the duty ratio is reduced to the extent that the operational time is shorter than a minimum possible time of operation of the solenoid, an operational time for which the solenoid is to be operated is determined within a new period composed of a plurality of consecutive basic periods.

Abstract: A hydraulic continuously variable speed transmission with a direct clutch valve comprises a hydraulic pump, a hydraulic motor, a hydraulic closed circuit for hydraulically connecting the both, a direct clutch valve placed in the closed circuit, a speed reduction ratio control actuator, and a direct clutch valve controlling device for controlling operations of said direct clutch valve to block the closed circuit when the speed reduction ratio becomes substantially "1". The direct clutch valve controlling device maintains a direct connecting state when an actual engine speed is higher than a direct clutch disconnecting reference engine speed at the speed reduction ratio of approximately "1". Then, the direct clutch valve control device releases the blocking of the closed circuit by the direct valve when a drop of the actual engine speed from the direct clutch disconnecting reference engine speed exceeds a predetermined amount corresponding to the vehicle speed.

Abstract: A continuously variable speed transmission comprises a continuously variable speed change mechanism, a ratio control actuator, a controller controlling operational direction and speed of the ratio control actuator, and a speed reduction ratio detection sensor. The controller, in the case of outputting a command to reverse the operational direction of the ratio control actuator, keeps the ratio control actuators actuating at a maximum actuation speed in the reverse operation direction, until the speed reduction ratio detection sensor detects a fact that the speed reduction ratio of the mechanism has changed into the reversed direction after output of the command.

Abstract: A hydraulic continuously variable speed transmission comprises a hydraulic closed circuit for hydraulically connecting the hydraulic pump and the hydraulic motor, a direct clutch valve placed in the closed circuit to block it, a speed reduction ratio control actuator to control the speed reduction ratio, a direct clutch actuator for moving said direct clutch valve from a full-open position to a full-closed position, ratio detecting means which detects the speed reduction ratio and valve position detecting means which detects position of the direct clutch valve to find if the direct clutch valve is moved to a slight-open position. The direct clutch valve is moved quickly from the full-open position to the slight-open position when it is found by the ratio detecting means that the speed reduction ratio has become "1", and then the direct clutch valve is moved slowly from the slight-open position to the full-closed position when it is found that the direct clutch valve has been moved to the slight-open position.

Abstract: The speed reduction ratio of a continuously variable speed transmission on a motor vehicle is controlled by continuously varying the speed reduction ratio in a range between a maximum speed reduction ratio and a minimum speed reduction ratio. A top limit speed reduction ratio corresponding to a speed of the motor vehicle and being higher than the minimium speed reduction ratio is set in a low vehicle speed range. The speed reduction ratio is controlled only between the maximum speed reduction ratio and the top limit speed reduction ratio in the low vehicle speed range.

Abstract: A vehicle engine throttle valve control apparatus whereby the actuation position of an accelerator pedal, the degree of opening of the throttle valve, and the position of the vehicle gear shift are detected. One of a plurality of different throttle valve target opening degree characteristics is then selected which corresponds to the current gear shift position, and the selected characteristic is used to set a target degree of opening for the throttle valve in accordance with the accelerator pedal position. The throttle valve is driven so as to make the actual degree of throttle opening become equal to the target value. Appropriate throttle control is thereby automatically performed each time a gear shift operation is executed, without intervention by the vehicle driver.

Abstract: A control system for a throttle valve in automotive internal combustion engines in which the throttle valve is both mechanically linked with an accelerator pedal and also connected with an actuator such as a pulse motor for fine-adjusting the opening of the throttle valve in the closing direction in accordance with the operating state of the engine after it has been opened through the mechanical linkage. A spring is inserted in the mechanical linkage system between the accelerator pedal and the throttle valve. The provision of the spring substantially isolates the accelerator pedal from forces acting in other parts of the system so that the operator does not feel an unnatural change in the amount of pressure needed to depress the accelerator pedal when the actuator goes into operation.

Abstract: A piston comprises a piston crown section, a piston skirt section connected to the piston crown section and having a pair of relatively flat, inclined portions at a pair of radially opposite locations thereof and a pair of piston pin boss sections disposed through and connected to the inclined portions of the piston skirt section, respectively, with the distance between the inclined portions being decreased from the maximum at the upper portion of the piston skirt section to the minimum at the lower portion of the piston skirt section.

Abstract: A throttle valve control system for an internal combustion engine sets a target manifold pressure for attaining a minimum fuel consumption rate in response to a detected engine rotational speed, and drives the throttle valve to a control opening determined so as to reduce the difference between the detected actual manifold pressure and the target manifold pressure. According to another feature, the system detects the operation position of the accelerator pedal and the throttle valve is driven to a control opening which is determined in accordance with the operation position of the accelerator pedal or the rate of change in the operation position of the accelerator pedal when the operation position or the rate of change in the operation position exceeds a predetermined value, respectively.

Abstract: A throttle valve control system for an internal combustion engine sets a target value of a pressure in an intake pipe of the engine for attaining a minimum fuel consumption rate in response to a detected engine rotational speed, and drives the throttle valve to an opening determined so as to reduce the difference between the detected actual pressure in the intake pipe and the target value of the pressure in the intake pipe. When the actual operation position of the throttle valve is not in an allowable range of a target throttle valve opening determined in response to the detected engine speed, the throttle valve is controlled to reduce the difference between the actual operation position of the throttle valve and the target throttle valve opening.

Abstract: A throttle valve control apparatus for an internal combustion engine uses a target throttle valve opening which is selected between one of a first opening valve determined according to the operation position of the accelerator pedal and a second opening value smaller than the first opening value. When the target throttle valve opening is switched from the second opening value to the first opening value, the driving speed of the throttle valve by a drive mechanism of the apparatus is controlled so as to maintain smooth operation of the engine.

Abstract: A throttle valve control system for a vehicle-mounted internal combustion engine, whereby engine operating parameters relating to engine load are detected, and a target value of a first engine operating parameter is established in accordance with an engine rotational speed, for example a target value which will endure minimum fuel consumption. The throttle valve is driven towards a control opening angle which is determined such as to reduce an amount of deviation of an actual value of the first engine operating parameter from the target value, but is held below an upper limit opening angle which is determined in accordance with an engine operating parameter.

Abstract: An engine throttle valve control apparatus whereby a reference throttle valve degree of the opening is established in accordance with the accelerator pedal actuation position and a reference opening degree characteristic. A boundary throttle valve degree of the opening is established in accordance with the accelerator pedal actuation position and at least one upper limit opening degree characteristic and a lower limit opening degree characteristic. A target degree of the throttle opening is computed from the relationship between the reference degree of the opening and a boundary degree of the opening, in conjunction with the contents of a characteristic command which can be freely selected. Thereby throttle valve is driven to reduce the deviation between the actual degree of the opening and the target degree of the opening.