Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
2000-04-12
2001-12-11
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C477S107000
Reexamination Certificate
active
06330504
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a driving force control for an automotive vehicle.
BACKGROUND OF THE INVENTION
The term “standard resistance” or “standard running resistance” is herein used to mean any force which opposes the motion of an automotive vehicle which is driven to keep on rolling over the surface of a flat road having 0% gradient at a constant vehicle speed. The term “running resistance” is herein used to mean any force that opposes the motion of an automotive vehicle, which is driven to keep on rolling over the surface of a road at a constant vehicle speed. Running resistance is equal to standard resistance if an automotive vehicle is driven to keep on rolling over the surface of a flat road having 0% gradient at a constant vehicle speed. Running resistance increases and becomes greater than standard resistance if the automotive vehicle is accelerated to increase speed from the constant vehicle speed. The term “acceleration resistance” is herein used to mean this increment or difference in running resistance that has occurred due to acceleration. Running resistance is greater when the automotive vehicle is driven to keep rolling over the surface of a flat road having gradient greater than 0% at a constant vehicle speed than standard resistance for the same vehicle speed. The term “gradient resistance” is used to mean this increment or difference in running resistance.
JP-A 6-88541 discloses a driving force control system for an automotive vehicle having an engine with an electronically controlled throttle and an automatic transmission. According to this known control system, a target driving torque is determined against current accelerator pedal opening and vehicle speed. First and second throttle opening degrees are calculated. The first throttle opening degree is a function of the target driving torque. The second throttle opening degree is proportional to the accelerator pedal opening degree. The first and second throttle opening degrees are combined to give a combined throttle opening degree. The combined throttle opening degree is applied to an electronically controlled throttle. A proportion of the first and second throttle opening degrees reflected in the lo combined throttle opening degree is determined in response to the accelerator opening degree.
A target engine output torque is determined which accomplishes the corrected target driving force. Over a range of manipulation or opening degree of the vehicle accelerator from zero percent to around fifty percent, the opening degree of the electronically controlled throttle valve is adjusted to accomplish a target driving torque that has been determined as a function of the corrected target driving force. Over a range from around fifty percent to one hundred percent, the opening degree of the throttle is determined as a linear function of the opening degree of the accelerator. This measure is intended to give the vehicle operator acceleration feel fit to the operator's demand.
JP-A 10-266882 discloses an attempt to smooth variation in driving force during operation with small values of accelerator pedal opening degree by referring to a plurality of maps stored against varying values of accelerator pedal opening degree, respectively. Each map contains varying values of target driving force against varying values of vehicle speed. For operation with small values of accelerator pedal opening, a map selected against one value of the accelerator pedal opening and the adjacent map selectable against another value of the accelerator pedal opening that is to be reached upon slightly depressing the accelerator pedal contain two different values of target driving force with a small difference.
SUMMARY OF THE INVENTION
U.S. patent application Ser. No. 09/518,691, filed Mar. 3, 2000, entitled “Driving Force Control With Gradient Resistance Torque Dependent Correction Factor” is pending and has been assigned to the same assignee to which the present application is to be assigned. This United States Patent Application claims priority based on Japanese Patent Application No. 11-58289 filed in Japan on Mar. 5, 1999. This United States Patent Application, which is hereby incorporated by reference in its entirety, has a corresponding European Patent Application that claims priority based on Japanese Patent Application No. 11-58289.
This United States Patent Application has proposed a driving force control system that includes an ordinary target driving force generator that generates an ordinary target driving force (tTd#n), and a running resistance increment generator that generates a running resistance increment (RESTRQ). The ordinary target driving force (tTd#n) is given after retrieving a map using accelerator pedal opening (APO) that is equivalent to operator's depression of the vehicle's accelerator pedal and vehicle speed (VSP). Referring to
FIGS. 5 and 10
, one dot chain line curve illustrates the variation of ordinary target driving force (tTd#n) when the vehicle operator depresses the vehicle's accelerator pedal from the released position. The proposed driving system further includes a driving force correction generator that determines a driving force correction (ADDFD) in response to the running resistance increment (RESTRQ), and a corrected target driving force generator where the driving force correction (ADDFD) is added to the ordinary target driving force (tTd#n) to produce a corrected target driving force driving force (tTd). This corrected target driving force (tTd) is used to determine a target engine torque (tTe) and a target CVT ratio (tRATIO). The fully drawn curve in
FIG. 10
or the broken line curve in
FIG. 5
illustrate the variation of the corrected target driving force (tTd) when the vehicle operator depresses the vehicle's accelerator pedal from the released position under a condition where the running resistance increment (RESTRQ) is large enough to cause the driving force correction generator to provide a substantial amount of driving force correction (ADDFD).
In the proposed driving force control system, even when the accelerator pedal is slightly depressed from its released position, the engine is adjusted to produce engine torque needed to accomplish the corrected target driving force that has been given after addition of the driving force correction (ADDFD) to the ordinary target driving force (tTd#n). If the driving force correction (ADDFD) is not zero, occurrence of shocks due to a change in engine torque is unavoidable.
In
FIG. 10
, the reference character A represents an operation point when the accelerator pedal is released. At the operation point A, the driving force correction (ADDFD) is zero so that correction of the ordinary target driving force (tTd#n) is not carried out. If the accelerator pedal is slightly depressed from the released position by an amount &agr;1, the driving force correction (ADDFD) becomes greater than zero so that the corrected driving force (tTd) jumps from the operation point A to an operation point B+, and then increases to an operation point C.
Accordingly, there occurs a rapid increase in driving force by &Dgr;Fd, causing a rapid increase in driving force from the operation point A, producing shocks.
During operation with the accelerator pedal released, suspension of fuel supply gains growing popularity in order to save fuel. If the ordinary target driving force (tTD#n) is corrected in response to a slight increase in depression of the vehicle's accelerator pedal from the released position where the fuel supply is suspended, a change in driving force grows substantially great in comparison with what is expected in response to the slight increase in depression of the accelerator pedal. This great change in driving force may cause the vehicle body to experience shocks and longitudinal vibration.
Subsequently, if the accelerator pedal is released from the slightly depressed position, where the driving force is corrected, to the released position, there is a shift from the
Nozaki Mikio
Toukura Nobusuke
Yasuoka Masayuki
Yoshinoya Daisuke
Cuchlinski Jr. William A.
Foley & Lardner
Gibson Eric M
Nissan Motor Co,. Ltd.
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