System for selecting between automatic and manual control of a number of gear ratios of a semiautomatic transmission
First Claim
1. A system for selecting between automatic and manual control of a number of gear ratios of a semiautomatic transmission, comprising:
- an internal combustion engine coupled to a semiautomatic transmission having a number of manually selectable gear ratios and a number of automatically selectable gear ratios;
means for determining an engine fueling rate;
a switch having a first switch position and a second switch position;
a memory unit including a software algorithm for controlling shifting between the number of automatically selectable gear ratios; and
a control computer responsive to said first switch position to execute said software algorithm and thereby control shifting between the automatically selectable gear ratios, said control computer responsive to said second switch position to inhibit execution of said software algorithm such that said number of automatically selectable gear ratios are manually selectable if said engine is currently engaged with any of said number of automatically selectable gear ratios and said fueling rate is less than a threshold fueling rate.
1 Assignment
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Accused Products
Abstract
A system for selecting between automatic and manual control of a number of gear ratios of a semiautomatic transmission includes an internal combustion engine coupled to a semiautomatic transmission having a number of manually selectable gear ratios and a number of automatically selectable gear ratios wherein the engine and transmission are both subject to management and control thereof by a control computer. A memory unit includes a software algorithm for controlling shifting between the automatically selectable gear ratios and the control computer is operable to execute the software algorithm. A switch is provided, which is preferably a cruise control enable/disable switch, wherein the control computer is responsive to a cruise control disable position of the switch to inhibit execution of the software algorithm and thereby subject the automatically selectable gear ratios to manual control thereof. The control computer is also responsive to a cruise control enable position of the switch to allow execution of the software algorithm to thereby subject the automatically selectable gear ratios to automatic control thereof. In one embodiment, the software algorithm is only inhibited after it has been determined that the engine fueling rate is below a fueling rate threshold if one of the automatically selectable gear ratios is currently engaged. According to another aspect of the invention, a gear down protection algorithm is instituted whenever the software algorithm for controlling automatic gear selection is disabled.
32 Citations
11 Claims
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1. A system for selecting between automatic and manual control of a number of gear ratios of a semiautomatic transmission, comprising:
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an internal combustion engine coupled to a semiautomatic transmission having a number of manually selectable gear ratios and a number of automatically selectable gear ratios;
means for determining an engine fueling rate;
a switch having a first switch position and a second switch position;
a memory unit including a software algorithm for controlling shifting between the number of automatically selectable gear ratios; and
a control computer responsive to said first switch position to execute said software algorithm and thereby control shifting between the automatically selectable gear ratios, said control computer responsive to said second switch position to inhibit execution of said software algorithm such that said number of automatically selectable gear ratios are manually selectable if said engine is currently engaged with any of said number of automatically selectable gear ratios and said fueling rate is less than a threshold fueling rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
and wherein said control computer is responsive to said second switch position to inhibit execution of said software algorithm if said engine is currently engaged with any of said number of automatically selectable gear ratios and said engine load is less than an engine load threshold.
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3. The system of claim 1 further including an accelerator pedal responsive to actuation thereof to produce an accelerator pedal signal;
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and wherein said means for determining an engine fueling rate includes means responsive to said accelerator pedal signal for determining a position of said accelerator pedal;
and wherein said control computer is responsive to said second switch position to inhibit execution of said software algorithm if said engine is currently engaged with any of said number of automatically selectable gear ratios and said accelerator pedal position is below an accelerator pedal position threshold for at least a predetermined time period.
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4. The system of claim 1 further including a cruise control unit responsive to a cruise control ON/OFF switch to correspondingly enable/disable said cruise control unit;
and wherein said switch is said cruise control ON/OFF switch with said first switch position corresponding to a ON position of said cruise control ON/OFF switch and said second switch position corresponding to an OFF position of said cruise control ON/OFF switch.
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5. The system of claim 1 further including at least one solenoid actuatable by said control computer to select at least one of said number of automatically selectable gear ratios and deactuatable by said control computer to deselect said at least one of said number of automatically selectable gear ratios;
and wherein said control computer is responsive to said second switch position to deactuate said at least one solenoid and thereafter inhibit execution of said software algorithm if said engine is engaged with any of said number of automatically selectable gear ratios and said fueling rate is less than said threshold fueling rate.
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6. The system of claim 1 wherein said control computer is further responsive to said second switch position to inhibit execution of said software algorithm such that said number of automatically selectable gear ratios are manually selectable if said engine is currently engaged with any of said number of manually selectable gear ratios.
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7. The system of claim 1 wherein said control computer is further responsive to said second switch position to complete an autoshift according to said software algorithm if said control computer is currently executing said autoshift, and thereafter inhibit execution of said software algorithm such that said number of automatically selectable gear ratios are manually selectable if said fueling rate is less than a threshold fueling rate.
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8. The system of claim 1 wherein said control computer is further responsive to said first switch position to enable execution of said software algorithm.
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9. The system of claim 1 wherein said control computer is responsive to a first program signal to respond to said switch as stated and to a second program signal to enable execution of said software algorithm at all times.
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10. A system for selecting between automatic and manual control of a number of gear ratios of a semiautomatic transmission, comprising:
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an internal combustion engine coupled to a semiautomatic transmission having a number of manually selectable gear ratios and a number of automatically selectable gear ratios;
means for determining engine load;
means for determining one of engine speed and vehicle road speed;
a memory unit including a software algorithm for controlling shifting between the number of automatically selectable gear ratios; and
a control computer operable in a first mode to execute said software algorithm and thereby control shifting between the automatically selectable gear ratios, and in a second mode to inhibit execution of said software algorithm such that said number of automatically selectable gear ratios are manually selectable, said control computer further operable in said second mode to determine a currently selected gear ratio of said transmission and reduce one of an engine speed limit and vehicle speed limit if a numerically lowest one of the selectable gear ratios is not currently selected and said engine load is below an engine load threshold, and to further reduce one of engine speed and vehicle speed if said one of engine speed and vehicle speed is above a corresponding one of said engine speed and vehicle speed limit. - View Dependent Claims (11)
means for calculating an instantaneous engine load percentage; and
a filter operable to filter the instantaneous engine load percentage and provide the engine load therefrom.
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Specification