Control apparatus and method for engine-continuously variable transmission

A control apparatus (as claimed in claim 12,) for a motor vehicle having an accelerator pedal, an engine having an intake pipe and a continuously variable transmission, the continuously variable transmission having a drive shaft drivingly connected to the engine, a driven shaft, a drive pulley including a cylinder chamber, a fixed conical disc secured to the drive shaft and a movable disc controllably movable in an axial direction of the drive shaft in response to fluid pressure in the cylinder chamber thereof, a driven pulley including a cylinder chamber, a fixed conical disc secured to the driven shaft, a movable disc controllably movable in an axial direction of the driven shaft in response to fluid pressure in the cylinder chamber thereof, and a V-belt running over the drive and driven pulleys to establish a driving connection therebetween, said control apparatus comprising:

• an accelerator pedal sensor means coupled with the accelerator pedal for generating an accelerator pedal stroke electric signal indicative of a depression degree of the accelerator pedal;
• an engine revolution speed sensor means coupled with the engine for generating an actual engine revolution speed electric signal indicative of an actual revolution speed of the engine;
• means for generating an output electric signal indicative of a target engine revolution speed, said output electric signal generating means coupled with said accelerator pedal sensor means for generating a first target engine revolution speed electric signal which is a first predetermined function of said accelerator pedal stroke electric signal;
• a fuel supply device control means coupled with said accelerator pedal sensor means for generating a target engine torque electric signal indicative of a target engine torque which is a second predetermined function of said accelerator pedal stroke electric signal;
• a comparator means coupled with said engine revolution speed sensor means and said output electric signal generating means for generating a deviation signal indicative of a difference between said actual engine revolution speed electric signal and said output electric signal;
• a shift control means coupled with said comparator means for varying a reduction ratio in the continuously variable transmission to vary the revolution speed of the engine in a direction to reduce said deviation signal;
• a fuel supply device communicating with the intake pipe and including a control element means for adjusting supply of fuel to the engine;
• and
• means coupled with said fuel supply device control function generator means for actuating said control element means in response to said target engine torque electric signal;
• wherein said shift control means comprises:
• a line pressure regulator valve means for providing a line pressure;
• a shift control valve driver means coupled with said comparator circuit means for generating an electric command signal in response to said deviation signal;
• and
• a shift control valve means communicating with said line pressure regulator valve means and coupled with said shift control valve driver means for controlling fluid supply to and fluid discharge from the cylinder chamber of the drive pulley and the cylinder chamber of the driven pulley such that when said first electric command signal is equal to said reference electric current, fluid pressure within the cylinder chamber of the drive pulley is made equal to that within the cylinder chamber of the driven pulley, when said first electric command signal is increased from said reference electric current, fluid pressure within the cylinder chamber of one of the drive and driven pulleys is decreased, and when said first electric command signal is decreased from said reference electric current, fluid pressure within the cylinder chamber of the other one of said drive and driven pulleys is decreased;
• said electric command signal being in the form of an electric current increasing and decreasing from a reference electric current,
• wherein said shift control valve means comprises:
• a valve body formed with a first valve bore, a second valve bore and a third valve bore,
• said first valve bore having a first port, a second port, a third port, a fourth port and a fifth port which are arranged such that said second port and fourth port are disposed between said first port and fifth port and said third port is disposed between said second port and fourth port;
• said first port and fifth port communicating with said line pressure regulator valve means to receive the line pressure therefrom, said third port serving as a drain port;
• a first spool slidably disposed in said first valve bore, the first spool having a first land, a second land and a third land and defining a first chamber between said first and second lands and a second chamber between said second and third lands;
• said first spool having a position wherein said second land agrees with and covers said third port, said first land uncovers said first port to form a clearance communicating with said first chamber and said third land uncovers said fifth port to form a clearance communicating with said second chamber;
• said first chamber communicating with the cylinder chamber of the drive pulley via said second port, said second chamber communicating with the cylinder chamber of the driven pulley via said fourth port;
• a second spool slidably disposed in said second valve bore and defining on a side near said first valve bore a third chamber communicating with said line pressure regulator valve means and on a side remote from said first valve bore a fourth chamber communicating with the cylinder chamber of the driven pulley;
• said second spool having a rod thereon extending through a partition wall between said first valve bore and second valve bore and contacting with the adjacent one of ends of said first spool;
• a spring disposed in said fourth chamber biasing said second spool toward said first spool;
• a third spool slidably disposed in said third valve bore and defining on a side near said first valve bore a chamber communicating with said line pressure regulator valve means and on a side remote from said first valve bore a chamber communicating with the cylinder chamber of the drive pulley;
• said third spool having a rod thereon extending through a partition wall between said first valve bore and third valve bore and contacting with the other of said ends of said first spool;
• a solenoid having a push rod contacting with said third spool to bias same toward said first spool with a force responsive to electric current passing through said solenoid;
• the force of said spring being so selected as to be equal in magnitude to the force of said push rod of said solenoid when said reference electric current is supplied to said solenoid.

A control apparatus for a motor vehicle having an accelerator pedal, an engine having an intake pipe and a continuously variable transmission, the continuously variable transmission having a drive shaft drivingly connected to the engine, a driven shaft, a drive pulley including a cylinder chamber, a fixed conical disc secured to the drive shaft and a movable disc controllably movable in an axial direction of the drive shaft in response to fluid pressure in the cylinder chamber thereof, a driven pulley including a cylinder chamber, a fixed conical disc secured to the drive shaft, a movable disc controllably movable in an axial direction of the driven shaft in response to fluid pressure in the cylinder chamber thereof, and a V-belt running over the drive and driven pulleys to establish a driving connection therebetween, said control apparatus comprising:

• an accelerator pedal sensor means coupled with the accelerator pedal for generating an accelerator pedal stroke electric signal indicative of a depression degree of the accelerator pedal;
• an engine revolution speed sensor means coupled with the engine for generating an actual engine revolution speed electric signal indicative of an actual revolution speed of the engine;
• means for generating an output electric signal indicative of a target engine revolution speed, said output electric signal generating means coupled with said accelerator pedal sensor means for generating a first target engine revolution speed electric signal which is a first predetermined function of said accelerator pedal stroke electric signal, said first predetermined function providing a single target engine revolution value for any single depression degree of the accelerator pedal;
• a fuel supply device control means coupled with said accelerator pedal sensor means for generating a target engine torque electric signal indicative of a target engine torque which is a second predetermined function of said accelerator pedal stroke electric signal, said second predetermined function providing a single target engine torque value for any single depression of the accelerator pedal;
• a comparator means coupled with said engine revolution speed sensor means and said output electric signal generating means for generating a deviation signal indicative of a difference between said actual engine revolution speed electric signal and said output electric signal;
• a vehicle speed sensor means coupled with the continuously variable transmission for generating a vehicle speed electric signal indicative of a vehicle speed;
• a selected shift position sensor means for generating a shift position signal indicative of a selected shift position by a shift lever;
• wherein said output electric signal generating means includes a limit engine revolution speed generator means coupled with said vehicle speed sensor means for generating a second target engine revolution speed electric signal which is a third predetermined function of said vehicle speed electric signal, and a switching means coupled with said engine revolution speed generator means, said limit engine revolution speed generator means and said selected shift position sensor means for allowing said first target engine electric signal to appear as said output electric signal when said shift position signal indicates that said shift lever is set to an ordinary drive range position and for allowing said second target engine revolution speed electric signal to appear as said output electric signal when said shift position signal indicates that said shift lever is set to one of a fixed reduction ratio position and a reverse drive position;
• a shift control valve driver means coupled with said comparator means for generating a command electric signal in response to said deviation signal;
• pumping means for supplying hydraulic fluid;
• means for regulating the fluid supplied by said pumping means to provide a line pressure which varies in direct proportional to the reduction ratio between the drive and driven pulleys and in inverse proportional to an intake manifold vacuum;
• and
• a shift control valve means connected to said line pressure regulator valve means to receive said line pressure and coupled with said shift control valve driver means for controlling fluid supply to both of the cylinder chambers and fluid discharge therefrom in response to said command electric signal.

A control apparatus for a motor vehicle having an accelerator pedal, an engine havng an intake pipe and a continuously variable transmission, the continuously variable transmission having a drive shaft drivingly connected to the engine, a driven shaft, a drive pulley including a cylinder chamber, a fixed conical disc secured to the drive shaft and a movable disc controllably movable in an axial direction of the drive shaft in response to fluid pressure in the cylinder chamber thereof, a driven pulley including a cylinder chamber, a fixed conical disc secured to the driven shaft, a movable disc controllably movable in an axial direction of the driven shaft in response to fluid pressure in the cylinder chamber thereof, and a V-belt running over the drive and driven pulleys to establish a driving connection therebetween, said control apparatus comprising:

• an accelerator pedal sensor means coupled with the accelerator pedal for generating an accelerator pedal stroke electric signal indicative of a depression degree of the accelerator pedal;
• an engine revolution speed sensor means coupled with the engine for generating an actual engine revolution speed electric signal indicative of an actual revolution speed of the engine;
• means for generating an output electric signal indicative of a target engine revolution speed, said output electric signal generating means coupled with said accelerator pedal sensor means for generating a first target engine revolution speed electric signal which is a first predetermined function of said accelerator pedal stroke electric signal;
• a fuel supply device control means coupled with said accelerator pedal sensor means for generating a target engine torque electric signal indicative of a target engine torque which is a second predetermined function of said accelerator pedal stroke electric signal;
• a comparator means coupled with said engine revolution speed sensor means and said output electric signal generating means for generating a deviation signal indicative of a difference between said actual engine revolution speed electric signal and said output electric signal;
• a shift control means coupled with said comparator means for varying a reduction ratio in the continuously variable transmission to vary the revolution speed of the engine in a direction to reduce said deviation signal;
• a fuel supply device communicating with the intake pipe and including a control element means for adjusting supply of fuel to the engine;
• means coupled with said fuel supply device control means for actuating said control element means in response to said target engine torque electric signal;
• a vehicle speed sensor means coupled with the countinuously variable transmission for generating a vehicle speed electric signal indicative of a vehicle speed;
• a selected shift position sensor means for generating a shift position signal indicative of a selected shift position by a shift lever;
• wherein said output electric signal generating means includes a limit engine revolution speed generator means coupled with said vehicle speed sensor means for generating a second target engine revolution speed electric signal which is a third predetermined function of said vehicle speed electric signal, and a switching means coupled with said engine revolution speed generator means, said limit engine revolution speed generator means and said selected shift position sensor means for allowing said first target engine electric signal to appear as said output electric signal when said shift position signal indicates that said shift lever is set to an ordinary drive range position and for allowing said second target engine revolution speed electric signal to appear as said output electric signal when said shift position signal indicates that said shift lever is set to one of a fixed reduction ratio position and a reverse drive position;
• wherein said shift control means comprises:
• a shift control valve driver means coupled with said comparator means for generating a first command electric signal in response to said deviation signal;
• pumping means for the hydraulic fluid;
• means for regulating the fluid supplied by said pumping means to provide a line pressure which varies in direct proportional to the reduction ratio between the drive and driven pulleys and in inverse proportional to an intake manifold vacuum;
• a shift control valve means connected to said line pressure regulator valve means to receive said line pressure and coupled with said shift control valve driver means for controlling fluid supply to both of the cylinder chambers and fluid discharge therefrom in response to said first command electric signal;
• wherein said means for regulating the fluid comprises:
• a reduction ratio arithmetic operation circuit means coupled with said engine revolution speed sensor means and said vehicle speed sensor means for generating a reduction ratio electric signal indicative of a reduction ratio between said drive and driven pulleys;
• a required line pressure generator means coupled with said reduction ratio arithmetic operation circuit for generating a required line pressure electric signal which is a predetermined function of said reduction ratio electric signal;
• a line pressure regulator valve driver means coupled with said required line pressure function generator means for generating a line pressure command electric signal in response to said required line pressure electric signal;
• and
• a line pressure regulator valve means coupled with said line pressure regulator valve driver means and communicating with the intake pipe for regulating the fluid supplied by said pumping means to provide said line pressure in response to said line pressure command electric signal and the intake manifold vacuum within the intake pipe;
• wherein said line pressure regulator valve means comprises:
• a valve body having a valve bore;
• a spool disposed within said valve bore, said spool having a large diameter portion and a small diameter portion;
• means defining a passage communicating with said pumping means to receive fluid therefrom;
• said small diameter portion defining within said valve bore a first chamber communicating with said passage, said small diameter portion and said large diameter portion defining therebetween a second chamber which is drained;
• said valve body having a port communicating with said second chamber and said passage;
• said small diameter portion being exposed to fluid pressure within said first chamber to bias said spool in a first direction away from said first chamber;
• means responsive to said line pressure command signal and intake manifold vacuum for pushing said spool in a second direction opposite to said first direction with a force variable in direct proportional to the reduction ratio and in inverse proportional to the intake manifold vacuum;
• and
• said large diameter portion covering said port to decrease an opening area to said second chamber when said spool moves in said second direction and uncovering said port to increase the opening area to said second chamber when said spool moves in said first direction.

A control apparatus for a motor vehicle having an accelerator pedal, an engine having an intake pipe and a continuously variable transmission, the continuously variable transmission having a drive shaft drivingly connected to the engine, a driven shaft, a drive pulley including a cylinder chamber, a fixed conical disc secured to the drive shaft and a movable disc controllably movable in an axial direction of the drive shaft in response to fluid pressure in the cylinder chamber thereof, a driven pulley including a cylinder chamber, a fixed conical disc secured to the driven shaft, a movable disc controllably movable in an axial direction of the driven shaft in response to fluid pressure in the cylinder chamber thereof, and a V-belt running over the drive and driven pulleys to establish a driving connection therebetween, said control apparatus comprising:

• an accelerator pedal sensor means coupled with the accelerator pedal for generating an accelerator pedal stroke electric signal indicative of a depression degree of the accelerator pedal;
• an engine revolution speed sensor means coupled with the engine for generating an actual engine revolution speed electric signal indicative of an actual revolution speed of the engine;
• means for generating an output electric signal indicative of a target engine revolution speed, said output electric signal generating means coupled with said accelerator pedal sensor means for generating a first target engine revolution speed electric signal which is a first predetermined function of said accelerator pedal stroke electric signal;
• a fuel supply device control means coupled with said accelerator pedal sensor means for generating a target engine torque electric signal indicative of a target engine torque which is a second predetermined function of said accelerator pedal stroke electric signal;
• a comparator means coupled with said engine revolution speed sensor means and said output electric signal generating means for generating a deviation signal indicative of a difference between said actual engine revolution speed electric signal and said output electric signal;
• a shift control means coupled with said comparator means for varying a reduction ratio in the continuously variable transmission to vary the revolution speed of the engine in a direction to reduce said deviation signal;
• a fuel supply device communicating with the intake pipe and including a control element means for adjusting supply of fuel to the engine;
• means coupled with said fuel supply device control means for actuating said control element means in response to said target engine torque electric signal;
• a vehicle speed sensor means coupled with the continuously variable transmission for generating a vehicle speed electric signal indicative of a vehicle speed;
• a selected shift position sensor means for generating a shift position signal indicative of a selected shift position by a shift lever;
• wherein said output electric signal generating means includes a limit engine revolution speed generator means coupled with said vehicle speed sensor means for generating a second target engine revolution speed electric signal which is a third predetermined function of said vehicle speed electric signal, and a switching means coupled with said engine revolution speed generator means, said limit engine revolution speed generator means and said selected shift position sensor means for allowing said first target engine electric signal to appear as said output electric signal when said shift position signal indicates that said shift lever is set to an ordinary drive range position and for allowing said second target engine revolution speed electric signal to appear as said output electric signal when said shift position signal indicates that said shift lever is set to one of a fixed reduction ratio position and a reverse drive position;
• wherein said shift control means comprises:
• a shift control valve driver means coupled with said comparator means for generating a first command electric signal in response to said deviation signal;
• pumping means for the hydraulic fluid;
• means for regulating the fluid supplied by said pumping means to provide a line pressure which varies in direct proportional to the reduction ratio between the drive and driven pulleys and in inverse proportional to an intake manifold vacuum;
• a shift control valve means connected to said line pressure regulator valve means to receive said line pressure and coupled with said shift control valve driver means for controlling fluid supply to both of the cylinder chambers and fluid discharge therefrom in response to said first command electric signal;
• wherein said means for regulating the fluid comprises:
• a valve body having a valve bore;
• a spool disposed within said valve bore, said spool having a large diameter portion and a small diameter portion;
• means defining a passage communicating with said pumping means to receive fluid therefrom;
• said small diameter portion defining within said valve bore a first chamber communicating with said passage, said small diameter portion and said large diameter portion defining therebetween a second chamber which is drained;
• said valve body having a port communicating with said second chamber and said passage;
• said small diameter portion being exposed to fluid pressure within said first chamber to bias said spool in a first direction away from said first chamber;
• means responsive to reduction ratio between the drive and driven pulleys and intake manifold vacuum for pushing said spool in a second direction opposite to said first direction with a force variable in direct proportional to the reduction ratio and in inverse proportional to the intake manifold vacuum;
• and
• said large diameter portion covering said port to decrease an opening area to said second chamber when said spool moves in said second direction and uncovering said port to increase the opening area to said second chamber when said spool moves in said first direction.

A control apparatus for a motor vehicle having an accelerator pedal, an engine having an intake pipe, comprising:

• an accelerator pedal sensor means coupled with the accelerator pedal for generating an accelerator pedal stroke electric signal indicative of a depression degree of the accelerator pedal;
• a fuel supply device communicating with the intake pipe to supply fuel into the intake pipe;
• means for controlling said fuel supply device in response to said accelerator pedal stroke electric signal;
• a throttle valve disposed within the intake pipe and operatively connected with the accelerator pedal;
• a safety throttle valve disposed within the intake pipe upstream of said throttle valve;
• and
• a mechanical means for connecting said safety throttle valve to the accelerator pedal so as to control the opening degree of said safety throttle valve in response to depression degree of the accelerator pedal such that the safety throttle valve is fully opened before the depression degree of the accelerator pedal becomes maximum.

A control apparatus for a motor vehicle having an accelerator pedal, an engine having an intake pipe, comprising:

• an accelerator pedal sensor means coupled with the accelerator pedal for generating an accelerator pedal stroke electric signal indicative of a depression degree of the accelerator pedal;
• a fuel supply device communicating with the intake pipe to supply fuel into the intake pipe;
• means for controlling said fuel supply device in response to said accelerator pedal stroke electric signal;
• a safety throttle valve disposed within the intake pipe;
• a mechanical means for connecting said safety throttle valve to the accelerator pedal so as to control the opening degree of said safety throttle valve in response to depression degree of the accelerator pedal such that the safety throttle valve is fully opened before the depression degree of the accelerator pedal becomes maximum;
• wherein said mechanical means comprises:
• a return spring means for biasing said safety throttle valve into a fully closed position;
• a stationary portion;
• a wire having one end connecting to said safety throttle valve and passing through said stationary portion, said wire having an other end;
• a stop fixed to said wire and disposed between said stationary portion and said safety throttle valve;
• a spring having one end connected to said other end of said wire and an other end;
• a mechanical linkage having one end connected to said other end of said spring and an other end connected to the accelerator pedal, said mechanical linkage being so constructed and arranged as to pull said spring in a direction tending to open said safety throttle valve as the depression degree of the accelerator pedal increases;
• said stop coming into contact with said stationary portion when said safety throttle valve is fully opened before the depression degree of the accelerator pedal becomes maximum and stopping further movement of said wire when the accelerator pedal is depressed further;
• said spring extending to allow further depression of the accelerator pedal after said stop has come into contact with said stationary portion.