Vehicles, electronic control units, and methods for gear shifting based on vehicle attitude

Abstract

A vehicle includes an engine, a plurality of drive wheels, a vehicle transmission configured to transmit power from the engine to the plurality of drive wheels, one or more vehicle attitude sensors, and an electronic control unit communicatively coupled to the one or more vehicle attitude sensors and the vehicle transmission. The electronic control unit is configured to receive a signal from the one or more vehicle attitude sensors, determine a degree of vehicle descent based on the signal received from the one or more vehicle attitude sensors, and downshift the vehicle transmission based on the degree of vehicle descent determined based on the signal received from the one or more vehicle attitude sensors.

What is claimed is: 
     
       1. A vehicle comprising:
 an engine; 
 a plurality of drive wheels; 
 a vehicle transmission configured to transmit power from the engine to the plurality of drive wheels; 
 one or more vehicle attitude sensors; and 
 an electronic control unit communicatively coupled to the one or more vehicle attitude sensors and the vehicle transmission, wherein the electronic control unit is configured to:
 receive a signal from the one or more vehicle attitude sensors; 
 determine a degree of vehicle descent based on the signal received from the one or more vehicle attitude sensors; 
 predict a predicted degree of vehicle descent based on a vehicle route; and 
 downshift the vehicle transmission when the predicted degree of vehicle descent and the determined degree of vehicle descent exceed a threshold degree of vehicle descent. 
 
 
     
     
       2. The vehicle of  claim 1 , wherein the electronic control unit is further configured to:
 determine a vehicle speed; 
 compare the determined vehicle speed to a threshold vehicle speed; and 
 downshift the vehicle transmission in response to comparing the determined vehicle speed to the threshold vehicle speed. 
 
     
     
       3. The vehicle of  claim 1 , wherein the electronic control unit is further configured to:
 calculate a predicted rotational velocity of the engine after the downshift; 
 compare the predicted rotational velocity of the engine to a threshold rotational velocity of the engine; and 
 downshift the vehicle transmission in response to comparing the predicted rotational velocity of the engine to the threshold rotational velocity of the engine. 
 
     
     
       4. The vehicle of  claim 1 , wherein the electronic control unit is further configured to:
 downshift the vehicle transmission when the determined degree of vehicle descent matches the predicted degree of vehicle descent. 
 
     
     
       5. The vehicle of  claim 1 , wherein the electronic control unit is further configured to:
 determine at least one of a weather condition and a road condition; and 
 downshift the vehicle transmission based on the determined degree of vehicle descent and the determined at least one of the weather condition and the road condition. 
 
     
     
       6. An electronic control unit for a vehicle, wherein the electronic control unit of the vehicle is configured to:
 receive a signal from one or more vehicle attitude sensors; 
 determine a degree of vehicle descent based on the signal received from the one or more vehicle attitude sensors; 
 predict a predicted degree of vehicle descent based on a vehicle route; and 
 downshift a vehicle transmission when the predicted degree of vehicle descent and the determined degree of vehicle descent exceed a threshold degree of vehicle descent. 
 
     
     
       7. The electronic control unit of  claim 6  further configured to:
 determine a vehicle speed; 
 compare the determined vehicle speed to a threshold vehicle speed; and 
 downshift the vehicle transmission in response to comparing the determined vehicle speed to the threshold vehicle speed. 
 
     
     
       8. The electronic control unit of  claim 6  further configured to:
 calculate a predicted rotational velocity of an engine after the downshift; 
 compare the predicted rotational velocity of the engine to a threshold rotational velocity of the engine; and 
 downshift the vehicle transmission in response to comparing the predicted rotational velocity of the engine to the threshold rotational velocity of the engine. 
 
     
     
       9. The electronic control unit of  claim 6  further configured to:
 downshift the vehicle transmission when the determined degree of vehicle descent matches the predicted degree of vehicle descent. 
 
     
     
       10. The electronic control unit of  claim 6  further configured to:
 determine at least one of a weather condition and a road condition; and 
 downshift the vehicle transmission based on the determined degree of vehicle descent and the determined at least one of the weather condition and the road condition. 
 
     
     
       11. A method of downshifting a vehicle transmission configured to transmit power from an engine to a plurality of drive wheels, the method comprising:
 receiving a signal from one or more vehicle attitude sensors; 
 determining a degree of vehicle descent based on the signal received from the one or more vehicle attitude sensors; 
 predicting a predicted degree of vehicle descent based on a vehicle route; and 
 downshifting the vehicle transmission when the predicted degree of vehicle descent and the determined degree of vehicle descent exceed a threshold degree of vehicle descent. 
 
     
     
       12. The method of  claim 11 , further comprising:
 determining a vehicle speed; 
 comparing the determined vehicle speed to a threshold vehicle speed; and 
 downshifting the vehicle transmission in response to comparing the determined vehicle speed to the threshold vehicle speed. 
 
     
     
       13. The method of  claim 11 , further comprising:
 calculating a predicted rotational velocity of the engine after the downshift; 
 comparing the predicted rotational velocity of the engine to a threshold rotational velocity of the engine; and 
 downshifting the vehicle transmission in response to comparing the predicted rotational velocity of the engine to the threshold rotational velocity of the engine. 
 
     
     
       14. The method of  claim 11 , further comprising:
 downshifting the vehicle transmission when the determined degree of vehicle descent matches the predicted degree of vehicle descent.