Apparatus for controlling engine brake force during vehicle running on downhill with released accelerator

An apparatus for controlling an engine brake force of a motor vehicle having an engine, an accelerator pedal, a brake pedal, and an automatic transmission which is shifted to change the speed ratio according to predetermined shifting conditions, said engine brake force being produced by said engine when said accelerator pedal is in a released state, said apparatus comprising:

• an accelerator position sensor for detecting an operating amount of said accelerator pedal;
• a vehicle speed sensor for detecting an actual running speed of the vehicle;
• determining means for determining whether said accelerator pedal is in said released state in which said operating amount is smaller than a predetermined threshold close to zero;
• first control means operated in response to a determination by said determining means that said accelerator pedal is in said released state, for increasing the engine brake force with an increase in said actual running speed of the vehicle detected by said vehicle speed sensor;
• brake detecting means for detecting that said brake pedal of the vehicle is depressed;
• an
• second control means operated in place of said first control means when said brake pedal is depressed, for controlling said engine brake force such that the engine brake force controlled by the second control means is larger than that controlled by said first control means.

An apparatus for controlling an engine brake force of a motor vehicle having an engine, an accelerator pedal, and an automatic transmission, said engine brake force being produced by said engine when said accelerator pedal is in a released state, said apparatus comprising:

• an accelerator position sensor for detecting an operating amount of said accelerator pedal;
• a vehicle speed sensor for detecting an actual running speed of the vehicle;
• desired-speed determining means for determining whether said operating amount of the accelerator pedal detected by said accelerator position sensor is reduced below a predetermined threshold which is close to zero, and determining a desired speed of the vehicle on the basis of said actual running speed detected by said vehicle-speed sensor when said operating amount is reduced below said predetermined threshold;
• engine brake control means for controlling said engine brake force so as to prevent said actual running speed of the vehicle detected by said vehicle speed sensor from exceeding said desired speed determined by said desired-speed determining means;
• and
• updating means for updating said desired speed of the vehicle on the basis of said actual running speed, when said actual running speed becomes smaller than said desired speed by more than a predetermined value.

An apparatus for controlling an engine brake force of a motor vehicle having an engine, an accelerator pedal, a brake pedal, and an automatic transmission, said engine brake force being produced by said engine when said accelerator pedal is in a released state, said apparatus comprising:

• an accelerator position sensor for detecting an operating amount of said accelerator pedal;
• a vehicle speed sensor for detecting an actual running speed of the vehicle;
• desired-speed determining means for determining whether said operating amount of the accelerator pedal detected by said accelerator position sensor is reduced below a predetermined threshold which is close to zero, and determining a desired speed of the vehicle on the basis of said actual running speed detected by said vehicle-speed sensor when said operating amount is reduced below said predetermined threshold;
• engine brake control means for controlling said engine brake force so as to prevent said actual running speed of the vehicle detected by said vehicle speed sensor from exceeding said desired speed determined by said desired-speed determining means;
• brake detecting means for detecting whether said brake pedal is depressed;
• and
• updating means operated when said brake pedal is depressed, for updating said desired speed of the vehicle on the basis of at least said actual running speed detected by said vehicle speed sensor when said brake pedal is released.