Vehicle speed control system
First Claim
1. A vehicle speed control system comprising:
- a speed setting section for setting a command vehicle speed;
a vehicle speed sensing section for sensing an actual vehicle speed;
a driving force calculating section for calculating a command driving force required to make the actual vehicle speed equal to the command vehicle speed;
an engine output calculating section for calculating a command engine output in accordance with the command driving force and the command vehicle speed;
a discriminating section for examining the command driving force to determine whether the command driving force is negative;
a command engine speed calculating section for storing a predetermined engine torque-versus-engine-speed characteristic relationship in an engine constraint state in which a throttle is fully closed and fuel cutoff is inhibited and for calculating a command engine speed corresponding to the command engine output, from the predetermined engine torque-versus-engine-speed characteristic relationship in the engine constraint state when the command driving force is negative;
a transmission ratio calculating section for calculating a command transmission ratio in accordance with the command engine speed;
an engine controlling section for putting an engine in the engine constraint state when the command driving force is negative; and
a transmission controlling section for controlling a continuously variable transmission in response to the command transmission ratio when the command driving force is negative.
1 Assignment
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Accused Products
Abstract
A vehicle speed control system comprises a section for calculating a command driving force-required to make a sensed vehicle speed equal to a preset command vehicle speed, a section for calculating a command engine output in accordance with the command driving force and the command vehicle speed, a section for calculating a command engine speed corresponding to the command engine output from a predetermined engine torque-versus-speed characteristic relationship in an engine constraint state of minimum throttle setting and fuel cutoff inhibition when the command driving. force is negative, and a section for calculating a command transmission ratio in accordance with the command engine speed. When the driving force command is negative, the control system put the engine in the constraint state and controls a continuously variable transmission in response to the command transmission ratio so as to prevent undesired vehicle speed hunting.
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Citations
19 Claims
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1. A vehicle speed control system comprising:
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a speed setting section for setting a command vehicle speed; a vehicle speed sensing section for sensing an actual vehicle speed; a driving force calculating section for calculating a command driving force required to make the actual vehicle speed equal to the command vehicle speed; an engine output calculating section for calculating a command engine output in accordance with the command driving force and the command vehicle speed; a discriminating section for examining the command driving force to determine whether the command driving force is negative; a command engine speed calculating section for storing a predetermined engine torque-versus-engine-speed characteristic relationship in an engine constraint state in which a throttle is fully closed and fuel cutoff is inhibited and for calculating a command engine speed corresponding to the command engine output, from the predetermined engine torque-versus-engine-speed characteristic relationship in the engine constraint state when the command driving force is negative; a transmission ratio calculating section for calculating a command transmission ratio in accordance with the command engine speed; an engine controlling section for putting an engine in the engine constraint state when the command driving force is negative; and a transmission controlling section for controlling a continuously variable transmission in response to the command transmission ratio when the command driving force is negative.
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2. A vehicle speed control system comprising:
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a speed setting section for setting a command vehicle speed; a vehicle speed sensing section for sensing an actual vehicle speed; a driving force calculating section for calculating a command driving force required to make the actual vehicle speed equal to the command vehicle speed; an engine output calculating section for calculating a command engine output in accordance with the command driving force and the command vehicle speed; a discriminating section for examining the command driving force to determine whether the command driving force is negative or not; a command engine speed calculating section for storing a predetermined engine torque versus speed characteristic relationship in a first state of fully closed throttle condition and fuel cutoff inhibiting condition and for calculating a command engine speed corresponding to the command engine output, from the predetermined engine torque versus speed characteristic relationship in the first state when the command driving force is negative;
atorque/ratio calculating section for calculating a command engine torque and a command transmission ratio to achieve the command driving force, the torque/ratio calculating section calculating the command transmission ratio in accordance with the command engine speed; a transmission controlling section for controlling a continuously variable transmission in response to the command transmission ratio, the transmission controlling section controlling the continuously variable transmission in response to the command transmission ratio when the command driving force is negative; and an engine controlling section for controlling an engine in response to the command engine torque, wherein, when the command driving force is negative, the engine controlling section sets an engine operating state in one of the first state of the fully closed throttle condition and the fuel cutoff inhibiting condition, and a second state of the fully closed throttle condition and a fuel cutoff condition, the engine controlling section selecting, as a selected engine constraint state, one of the first and second states, and switching the engine operating state between the first and second states in accordance with the command engine output. - View Dependent Claims (3)
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4. A vehicle speed control system comprising:
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a speed setting section for setting a command vehicle speed; a vehicle speed sensing section for sensing an actual vehicle speed; a driving force calculating section for calculating a command driving force required to make the actual vehicle speed equal to the command vehicle speed; an engine output calculating section for calculating a command engine output in accordance with the command driving force and the command vehicle speed; a command engine speed calculating section for storing a predetermined engine torque versus speed characteristic relationship in a first state of fully closed throttle condition and fuel cutoff inhibiting condition and for calculating a command engine speed corresponding to the command engine output, from the predetermined engine torque versus speed characteristic relationship in the first state when the command driving force is negative; a torque/ratio calculating section for calculating a command engine torque and a command transmission ratio to achieve the command driving force, the torque/ratio calculating section calculates the command transmission ratio in accordance with the command engine speed; a transmission controlling section for controlling a continuously variable transmission in response to the command transmission ratio, the transmission controlling section controlling the continuously variable transmission in response to the command transmission ratio when the command driving force is negative; and an engine controlling section for controlling an engine in response to the command engine torque, wherein, when the command driving force is negative, the engine controlling section sets an engine operating state in one of the first state of the fully closed throttle condition and the fuel cutoff inhibiting condition, and a second state of the fully closed throttle condition and a fuel cutoff condition, the engine controlling section selecting, as a selected engine constraint state, one of the first and second states, and switching the engine operating state between the first and second states in accordance with an engine speed. - View Dependent Claims (5)
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6. A vehicle speed control system comprising:
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a speed setter for setting a command vehicle speed; a vehicle speed sensor for sensing an actual vehicle speed; an engine controlling device for controlling an engine of a vehicle in response to a command engine torque; a transmission controlling device for controlling a continuously variable transmission in response to a command transmission ratio; and a controller for calculating a command driving force required to reduce a vehicle speed deviation of the actual vehicle speed from the command vehicle speed, for calculating a command engine output in accordance with the command driving force and the command vehicle speed, for calculating a command engine speed corresponding to the command engine output according to a predetermined engine torque-speed characteristic relationship in an engine constraint state of fully closed throttle condition and a fuel cutoff inhibit condition when the command driving force is negative, for further calculating the command transmission ratio in accordance with the command engine speed, for causing the engine controlling device to put the engine in the engine constraint state when the command driving force is negative and for causing the transmission controlling device to control the transmission in accordance with the command transmission ratio. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A vehicle speed control system comprising:
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a speed setter for setting a command vehicle speed; a vehicle speed sensor for sensing an actual vehicle speed; an engine controlling device for controlling an engine of a vehicle in response to a command engine torque; a transmission controlling device for controlling a continuously variable transmission in response to a command transmission ratio; and a controller for calculating a command driving force required to reduce a vehicle speed deviation of the actual vehicle speed from the command vehicle speed, for calculating a command engine output in accordance with the command driving force and the command vehicle speed, for calculating a command engine speed corresponding to the command engine output according to a predetermined engine torque-speed characteristic relationship in an engine constraint state of fully closed throttle condition and a fuel cutoff inhibit condition when the command driving force is negative, for further calculating the command transmission ratio in accordance with the command engine speed, for causing the engine controlling device to put the engine in the engine constraint state when the command driving force is negative and for causing the transmission controlling device to control the transmission in accordance with the command transmission ratio, wherein the command engine output is proportional to a product of the command driving force and the command vehicle speed, and the command engine speed increases as the command output decreases when the command driving force is negative. - View Dependent Claims (16)
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17. A vehicle speed control method comprising:
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a speed setting step for setting a command vehicle speed; a vehicle speed sensing step for sensing an actual vehicle speed; a driving force calculating step for calculating a command driving force required to make the actual vehicle speed equal to the command vehicle speed; an engine output calculating step for calculating [an] a command engine output in accordance with the command driving force and the command vehicle speed; a discriminating step for examining the command driving force to determine whether the command driving force is negative; a command engine speed calculating step for storing a predetermined engine-torque-versus-engine-speed characteristic relationship in an engine constraint state in which a throttle is fully closed and fuel cutoff is inhibited and for calculating a command engine speed corresponding to the command engine output, from the predetermined engine torque-versus-engine-speed characteristic relationship in the engine constraint state when the command driving force is negative; a transmission ratio calculating step for calculating a command transmission ratio in accordance with the command engine speed; an engine controlling step for putting an engine in the engine constraint state when the command driving force is negative; and a transmission controlling step for controlling a continuously variable transmission in response to the command transmission ratio when the command driving force is negative. - View Dependent Claims (18, 19)
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Specification