Variable electronically controlled shift points for a cruise control system

A method for automatically controlling speed and transmission shifting of an engine powered vehicle in response to receiving a desired speed input from the driver, said method comprising the steps of:

• providing an engine;
• providing a manual/automatic transmission having a plurality of manually engagable gear ratio operation states and a first and a second automatically engagable gear ratio operation states, said first and second gear ratio operation states actuated in response to downshift and upshift signals, respectively, supplied to an input of said transmission;
• sensing vehicle speed and producing a speed signal corresponding thereto;
• sensing engine speed and producing an RPM signal corresponding thereto;
• inputting a desired vehicle speed value from the driver;
• fueling said engine, said fueling step including responding to said speed signal and adjusting the fueling supply rate for the engine in an attempt to maintain said speed signal within a predetermined deviation from said desired speed value;
• producing said downshift signal according to the following downshift equation:
• ##STR10## upshift equation:
• ##STR11## wherein the variables of the upshift and downshift equations are defined as follows:
• RPM=engine speed;
• VSS=vehicle speed;
• HS.sub.-- IDLE.sub.-- RPM is a rated engine speed value defining a maximum operational engine speed based upon engine design;
• cruise.sub.-- set.sub.-- speed is a cruise control set speed established by the driver during cruise control operation;
• cruise.sub.-- dwn.sub.-- rpm is a scaling factor multiplied times HS.sub.-- IDLE.sub.-- RPM to produce a first engine speed value below rated engine speed of the engine;
• CRU.sub.-- DWN.sub.-- RPM2 is a scaling factor multiplied time HS.sub.-- IDLE.sub.-- RPM to produce a second engine speed value that is less than CRUISE.sub.-- DWN.sub.-- RPM * HS.sub.-- IDLE.sub.-- RPM;
• CRUISE.sub.-- UP.sub.-- RPM is a scaling factor multiplied times HS.sub.-- IDLE.sub.-- RPM to produce a third engine speed value;
• CRU.sub.-- UP.sub.-- RPM2 is a scaling factor multiplied time HS.sub.-- IDLE.sub.-- RPM to produce a fourth engine speed value that is greater than CRUISE.sub.-- UP.sub.-- RPM * HS.sub.-- IDLE.sub.-- RPM;
• CRUISE.sub.-- DWN is a first vehicle speed offset value;
• and
• CRUISE.sub.-- UP is a second vehicle speed offset value.

A cruise control system for maintaining a substantially constant vehicle speed for an engine powered vehicle in response to receiving a desired speed signal from the driver of the vehicle, said cruise control system comprising:

• an engine;
• a manual/automatic transmission having a manual mode of operation including a plurality of manually engagable gear ratio operation states, and an automatic mode of operation including first and second automatically engagable gear ratio operation states, said first and second automatically engagable gear ratio operation states actuated in response to downshift and upshift signals, respectively, supplied to an input of said transmission;
• shift means for enabling driver selection between said manually engagable gear ratio states and said automatic mode of operation;
• means for inputting from the driver said desired speed signal;
• means for determining engine speed and producing an RPM signal corresponding thereto;
• means for determining vehicle speed and producing a speed signal corresponding thereto;
• means responsive to said desired speed input for fueling said engine to maintain said substantially constant vehicle speed;
• and
• programmable means comprising a programmed data processor for producing said downshift and said upshift signal, said programmable means monitoring said desired speed signal, said RPM signal and said speed signal and producing said downshift signal when said RPM signal is below a first predetermined engine speed level and said speed signal is below a first predetermined vehicle speed level or when said RPM signal is below a second predetermined engine speed level wherein said first predetermined engine speed level is greater than said second predetermined engine speed level, and said first predetermined vehicle speed level is less than said desired speed signal, said programmable means producing said upshift signal when said RPM signal is greater than a third predetermined engine speed level and said vehicle speed signal is greater than a second predetermined vehicle speed level or when said RPM signal is above a fourth predetermined engine speed level, wherein said third predetermined engine speed level is less than said fourth predetermined engine speed level, and said second predetermined vehicle speed level is greater than said desired speed signal.

A transmission shift control system comprising:

• an engine having a throttle control;
• means for monitoring the position of said throttle control and producing a throttle signal having a closed throttle state and an open throttle state;
• a manual/automatic transmission having a manual mode of operation including a plurality of manually engagable gear ratio operation states, and an automatic mode of operation including first and second automatically engagable gear ratio operation states, said first and second automatically engagable gear ratio operation states actuated in response to downshift and upshift signals, respectively, supplied to an input of said transmission;
• shift means for enabling driver selection between said manually engagable gear ratio states and said automatic mode of operation;
• means for determining engine speed and producing an RPM signal corresponding thereto;
• means for determining vehicle speed and producing a speed signal corresponding thereto;
• and
• programmable means comprising a programmed data processor for producing said downshift and said upshift signal, said programmable means monitoring said throttle signal, said RPM signal and said speed signal and:
• a) producing said upshift signal when said RPM signal is greater than a first predetermined engine speed level and said throttle signal is in said throttle open state;
• b) producing said upshift signal when said RPM signal is greater than said first predetermined engine speed level minus a first predetermined offset level and said throttle signal is in said throttle closed state;
• c) producing said downshift signal when said RPM signal is less than or equal to first predetermined engine speed level and said throttle signal is in said throttle open state;
• d) producing said downshift signal when said RPM signal is less than said first predetermined engine speed level minus a second predetermined offset level and said throttle signal is in said throttle closed state.

A method for producing shift signals for a transmission comprising the steps of:

• providing an engine having a throttle control;
• monitoring the position of said throttle control and producing a throttle signal having a closed throttle state and an open throttle state;
• providing a manual/automatic transmission having a manual mode of operation including a plurality of manually engagable gear ratio operation states, and an automatic mode of operation including first and second automatically engagable gear ratio operation states, said first and second automatically engagable gear ratio operation states actuated in response to downshift and upshift signals, respectively, supplied to an input of said transmission;
• enabling driver selection between said manually engagable gear ratio states and said automatic mode of operation;
• determining engine speed and producing an RPM signal corresponding thereto;
• determining vehicle speed and producing a speed signal corresponding thereto;
• producing said upshift signal when said RPM signal is greater than a first predetermined engine speed level and said throttle signal is in said throttle open state;
• producing said upshift signal when said RPM signal is greater than said first predetermined engine speed level minus a first predetermined offset level and said throttle signal is in said throttle closed state;
• producing said downshift signal when said RPM signal is less than or equal to first predetermined engine speed level and said throttle signal is in said throttle open state;
• and
• producing said downshift signal when said RPM signal is less than said first predetermined engine speed level minus a second predetermined offset level and said throttle signal is in said throttle closed state.

A control system for automatically controlling transmission shifting of an engine powered vehicle comprising:

• an engine;
• a manual/automatic transmission including a plurality of manually engagable gear ratio operation states and a first and a second automatically engagable gear ratio operation states, said first and second gear ratio operation states actuated in response to downshift and upshift signals, respectively, supplied to an input of said transmission;
• means for sensing vehicle speed and producing a speed signal corresponding thereto;
• means for sensing engine speed and producing an RPM signal corresponding thereto;
• throttle means responsive to driver commands for producing a throttle signal corresponding to the engine throttle level desired by the driver;
• means for fueling said engine, said means for fueling responding to said throttle signal and adjusting the fueling supply rate for the engine in accordance therewith;
• means for producing said downshift signal according to the following downshift equation:
• ##STR12## then produce said downshift signal;
• and means for producing said upshift signal according to the following upshift equation:
• ##STR13## then produce said upshift signal;
• wherein the variables of the upshift and downshift equations are defined as follows:
• RPM=engine speed;
• HS.sub.-- IDLE.sub.-- RPM is a rated engine speed value defining a maximum operational engine speed based upon engine design;
• NORMAL.sub.-- DWN is a scaling factor multiplied times HS.sub.-- IDLE.sub.-- RPM to obtain a downshift engine speed at which a downshift from said second gear ratio operation state to said first gear ratio operation, state is desired if THROTTLE is not closed;
• NORMAL.sub.-- UP is a scaling factor multiplied times HS.sub.-- IDLE.sub.-- RPM to obtain an upshift engine speed at which an upshift from said first gear ratio operation state to said second gear ratio operation state is desired if THROTTLE is not CLOSED;
• COAST.sub.-- DWN is a scaling factor multiplied times HS.sub.-- IDLE.sub.-- RPM to produce a first engine speed value at which a downshift is desired when the throttle is closed;
• COAST.sub.-- UP is a scaling factor multiplied time HS.sub.-- IDLE.sub.-- RPM to produce a second engine speed at which an upshift is desired when the throttle is CLOSED;
• THROTTLE corresponds to the throttle signal;
• and
• CLOSED is a position of said throttle means corresponding to a throttle signal below a predetermined level thereby indicating that the driver is not requesting fuel flow to the engine above a predetermined idle speed throttle setting.