Toyota Jidosha Kabushiki Kaisha

Takeshi Gono

Akinori Osanai

Takao Niwa

Souichi Matsushita

A spark-ignited direct cylinder fuel injection engine is provided with a combustion chamber formed in a depression on the surface of each piston, and a direct cylinder fuel injection valve spraying a fuel mist directly in the combustion chamber. In the wall of the combustion chamber an arc-shaped first wall surface region is located on the upstream side of the combustion chamber with respect to the swirl flow direction of the intake air. Continuous with the first wall surface region, a straight second wall surface region is formed at the downstream side of the first wall surface region. An arc shaped third wall surface region is formed at the downstream side of the second wall surface region. A spark plug is positioned so that it protrudes into the depressed combustion chamber at the region near the second wall surface region when the piston is positioned at its top dead center. Fuel is injected into the first wall surface region part of the combustion chamber, and carried by the intake swirl flow toward the third wall surface region part of the combustion chamber while it is being diffused and vaporized. Therefore, when flowing along the second wall surface near the spark plug, the injected fuel forms an ignitable air-fuel mixture, thus stable ignition, by the spark plug, is obtained regardless of the amount of the fuel injected into the combustion chamber.

Spark-ignited direct cylinder fuel injection engine

A continuously variable transmission (CVT) used in a vehicle is controlled such that an actual engine speed Ne is equalized to a desired engine speed Ne'. A reference engine speed Ner is defined to be nearly equal to and less than Ne'. When Ne&lt;Ner, or Ne&gt;Ne', the speed ratio e of the CVT is allowed to be changed, while the change is inhibited when Ner.ltoreq.Ne&lt;Ne'.

Apparatus for controlling continuously variable transmission

A method for controlling a continuously variable transmission installed in a vehicle. The method utilizes a changing rate for varying a RPM ratio between an output shaft and an input shaft to compensate for large and small throttle openings as well as varying rates of changing the throttle opening.

Method for controllig a controlling a continuously variable transmission

Method and apparatus for controlling a continuously variable transmission operatively connecting an engine and drive wheels of a vehicle, wherein a speed ratio of the transmission is controlled such that an actual engine speed coincides with a target engine speed. The method and apparatus comprise steps or devices for: determining a normal target speed based on a currently required output of the engine; determining a rate of variation in the speed ratio of the transmission; determining a transmission efficiency of the transmission based on the determined rate of variation in the speed ratio; determining a variation-restraint trigger speed based on the determined transmission efficiency and on the determined normal target speed, the trigger speed being lower than the normal target speed; restraining the rate of variation in the speed ratio while the actual engine speed is raised from the trigger speed to the normal target speed during acceleration of the vehicle; and selecting the trigger speed as a special target speed when the actual engine speed has been raised to the normal target speed. After the special target speed has been selected, the transmission is controlled such that the engine speed is lowered to the special target speed, i.e., to the variation-restraint trigger speed.

Method and apparatus for controlling continuously variable transmission

Method and apparatus for controlling a continuously variable transmission operatively connecting an engine and drive wheels of a vehicle, wherein a speed ratio of the transmission is controlled such that an actual engine speed coincides with a target engine speed. The method and apparatus comprise steps or devices for: determining a first target speed based on a currently required output of the engine; determining a second target speed based on a predetermined transmission efficiency of the transmission and on the first target speed, the second target speed being lower than the first target speed; determining a variation-resistant trigger speed based on a detected running speed of the vehicle, the trigger speed being within a speed range in which the engine provides a sufficient output necessary to permit desired acceleration of the vehicle; restraining a rate of variation in the speed ratio while the actual engine speed is raised from the trigger speed to the first target speed; and switching the target engine speed from the first target speed to the second target speed when the actual engine speed has been raised to the first target speed, whereby the engine speed is lowered from the first target speed to the second target speed. When the second target speed is reached, the second target speed is changed to the first target speed.

The apparatus for controlling the CVT for a vehicle includes means for controlling a desired speed ratio of the CVT, means for storing a map of engine speed versus positions of the throttle valve for providing the minimum fuel consumption and means for calculating, by use of the map, a desired engine speed value corresponding to the detected throttle position. Also provided are means for determining a first operating area of the engine speed based upon the throttle opening, which area is spaced from the desired engine speed and is capable of providing sufficient power to obtain a smooth acceleration at a fixed transmission ratio as well as means for determining a second operating area of the engine speed based on the vehicle speed where the engine speed is high in relation to the vehicle speed, the second area being spaced from the desired engine speed and being capable of providing sufficient power to obtain a smooth acceleration at a fixed transmission ratio. Means are also provided for providing a signal to the transmission varying means for maintaining a current fixed speed ratio when the engine is operating in the first or second area, as well as means for providing a signal to the transmission varying means for varying the speed ratio so that the actual engine speed corresponds to the desired engine speed when the engine is in an area other than the first and second areas.

Method and apparatus for controlling a continuously variable transmission operatively connecting an engine and drive wheels of a vehicle, wherein a speed ratio of the transmission is controlled such that an actual engine speed coincides with a target engine speed determined based on a currently required engine output and according to a predetermined relation between the target engine speed and the required engine output. The method and apparatus comprise a step or device for restraining a rate of variation in the speed ratio during a time span between the moment when the actual engine speed or output has exceeded a variation-restraint trigger speed or output of the engine, and the moment when the actual engine speed or output has reached the target speed or output. The trigger engine speed or output is determined based on a predetermined transmission efficiency of the transmission, and on the target engine speed or output, and is lower or smaller than the target engine speed or output.

Method and apparatus for controlling a continuously variable transmission operatively connecting an engine and drive wheels of a vehicle, wherein a speed ratio of the transmission is controlled such that an actual engine speed coincides with a target engine speed. The method and apparatus comprise steps or devices for: determining a normal target speed and a variation-restraint trigger speed based at least on a currently required output of the engine, the normal target speed being higher than the trigger speed and normally used as the target engine speed; restraining a rate of variation in the speed ratio while the actual engine speed is raised from the trigger speed to the normal target speed during acceleration of the vehicle; and selecting the trigger speed as a special target speed when the actual engine speed has been raised to the normal target speed. After the special target speed has been selected, the transmission is controlled such that the engine speed is lowered to the special target speed, i.e., to the variation-restraint trigger speed.

Method and apparatus for controlling a continuously variable transmission operatively connecting an engine and drive wheels of a vehicle, wherein a speed ratio of the transmission is controlled such that an actual engine speed coincides with a target engine speed determined based on a currently required engine output and according to a predetermined relation between the target engine speed and the required engine output. The method and apparatus comprise a step or device for restraining a rate of variation in the speed ratio during a time span between the moment when the actual engine speed has exceeded a variation-restraint trigger speed of the engine, and the moment when the actual engine speed has reached the target speed. The trigger engine speed is lower than the target engine speed, and determined based on a transmission efficiency of the transmission. The transmission efficiency is determined based on a detected changing rate of variation in the speed ratio of the transmission.

A continuously variable transmission (CVT) is controlled such that an actual engine speed Ne is equalized to a desired engine speed Ne'. Defining Nc as a positive constant, the speed ratio e of the CVT is substantially fixed during a period of time when the Ne changes from Ne&lt;Ne'-Nc to Ne'-Nc.ltoreq.Ne&lt;Ne' and then changes to Ne.gtoreq.Ne'. Ne'-Nc is defined as a temporarily desired engine speed during a period of time when the Ne changes from Ne.gtoreq.Ne' to Ne'-Nc.ltoreq.Ne&lt;Ne' and then changes to Ne&lt;Ne'-Nc. During the period of time the speed ratio of the CVT is changed such that the actual engine speed Ne is equalized to the temporarily desired engine speed Ne'-Nc.

Method and apparatus for controlling a continuously variable transmission for a vehicle for transmitting an output of an engine of the vehicle to its drive wheels, comprising a step or device for detecting an engine speed, a step or device for detecting a vehicle running speed, a step or device for sensing a vacuum pressure in an intake manifold connected to the engine, a step or device for determining an actual engine output based on the detected engine speed and the sensed intake vacuum pressure, a step or device for determining a target engine speed based on the detected vehicle running speed and the determined actual engine output, and according to a predetermined relation among the target engine speed, the vehicle running speed and the actual engine output, said relation being predetermined to attain a required output of the engine with a minimum specific fuel consumption, and further comprising a step or device for controlling the speed ratio such that the detected engine speed coincides with the target engine speed.

Method and apparatus for controlling a continuously variable transmission for a vehicle for transmitting an output of an engine of the vehicle to its drive wheels, comprising a step or device for detecting a running speed of the vehicle, a step or device for sensing a flow of an intake gas through an intake manifold toward the engine, a step or device for determining a target engine speed based on the detected running speed and the sensed intake gas flow, and according to a predetermined relation among the target engine speed, the running speed and the intake gas flow, which relation is predetermined to attain a required output of the engine with a minimum specific fuel consumption, and further comprising a step or device for controlling the speed ratio such that a speed of the engine coincides with the determined target engine speed.

A method for controlling a continuously variable transmission installed in a vehicle. The method utilizes a changing rate for varying an RPM ratio between an output shaft and an input shaft to permit rapid acceleration of a vehicle when needed as well as fuel consumption efficiency. The rate of changing the RPM ratio is a function of the actual velocity of the vehicle and a difference between the desired RPM of a driving pulley and an actual RPM of a driving pulley.

Method for controlling a rate of changing an RPM ratio in a continuously

An apparatus for controlling speed ratios of a continuously variable transmission who enables to obtain a fixed vehicle speed when an engine brake is effected. The continuously variable transmission has a means which memorizes a desired vehicle speed under a condition when the vehicle runs under the effect of the engine brake, and a speed ratio control means which controls the speed ratios so that the desired vehicle speed may equal the actual vehicle speed.

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Susono, Japan

Takeshi Gono