Hybrid driveline control

Abstract

A computer system has processing circuitry to obtain a wanted speed of a marine vessel comprising a hybrid driveline; determine a first target speed for an electric propulsion source connected to the hybrid driveline based on the wanted speed and a speed threshold; determine a second target speed for a combustion propulsion source connected to the hybrid driveline based on the wanted speed and the speed threshold. A difference between the first target speed and the second target speed decreases with a difference between said target speeds and the speed threshold.

What is claimed is: 
     
         1 . A computer system comprising processing circuitry configured to:
 obtain a wanted speed of a marine vessel comprising a hybrid driveline;   determine a first target speed for an electric propulsion source connected to the hybrid driveline based on the wanted speed and a speed threshold;   determine a second target speed for a combustion propulsion source connected to the hybrid driveline based on the wanted speed and the speed threshold; wherein a difference between the first target speed and the second target speed decreases with a difference between said target speeds and the speed threshold; and   control the electric propulsion source to the first target speed and the combustion propulsion source to the second target speed.   
     
     
         2 . The computer system of  claim 1 , wherein the processing circuitry is further configured to:
 responsive to the wanted speed being at the speed threshold:   determine the first and second target speed to be at the wanted speed.   
     
     
         3 . The computer system of  claim 1 , wherein the speed threshold is determined based on a power threshold associated with the used power of the hybrid driveline. 
     
     
         4 . The computer system of  claim 1 , wherein the speed threshold is determined based on a planing speed of the marine vessel. 
     
     
         5 . The computer system of  claim 1 , wherein the processing circuitry is further configured to:
 responsive to the wanted speed being below the speed threshold:
 determine the first target speed to be at the wanted speed, and 
 determine the second target speed to be lower than the wanted speed. 
   
     
     
         6 . The computer system of  claim 1 , wherein the processing circuitry is further configured to:
 responsive to the wanted speed being above the speed threshold:
 determine the first target speed to be lower than the wanted speed, and 
 determine the second target speed to be at the wanted speed. 
   
     
     
         7 . The computer system of  claim 1 , wherein the processing circuitry is further configured to:
 responsive to the wanted speed being below the speed threshold:
 determine the first target speed to be lower than the wanted speed, and determine the second target speed to be at the wanted speed. 
   
     
     
         8 . The computer system of  claim 1 , wherein the speed threshold is a predetermined threshold based on a planing speed of the marine vessel, and wherein the processing circuitry is further configured to:
 responsive to the wanted speed being below the speed threshold:
 determine the first target speed to be at the wanted speed, and determine the second target speed to be lower than the speed threshold, 
   
       and wherein the processing circuitry is further configured to:
 response to the wanted speed being above the speed threshold:
 determine the first target speed to be lower than the speed threshold, and 
 determine the second target speed to be at the wanted speed. 
 
 
     
     
         9 . A hybrid driveline for a marine vessel comprising an electric propulsion source and a combustion propulsion source connected to a propeller shaft of the hybrid driveline, and operatively connected the computer system of  claim 1 . 
     
     
         10 . The hybrid driveline of  claim 9 , wherein the wanted speed is a speed of the propeller shaft. 
     
     
         11 . The hybrid driveline of  claim 9 , wherein the electric propulsion source is connected to the propeller shaft by a freewheel gear. 
     
     
         12 . The hybrid driveline of  claim 11 , wherein the electric propulsion source and the combustion propulsion source are connected to the propeller shaft at separate sides of the freewheel gear. 
     
     
         13 . A marine vessel comprising the hybrid driveline of  claim 9 . 
     
     
         14 . A computer implemented method comprising:
 obtaining, by processing circuitry of a computer system, a wanted speed of a marine vessel comprising a hybrid driveline;   determining, by the processing circuitry, a first target speed for an electric propulsion source connected to the hybrid driveline based on the wanted speed and a speed threshold;   determining, by the processing circuitry, a second target speed for a combustion propulsion source connected to the hybrid driveline based on the wanted speed and the speed threshold; wherein a difference between the first target speed and the second target speed decreases with a difference between the target speeds and the speed threshold; and   controlling, by the processing circuitry, the electric propulsion source to the first target speed and the combustion propulsion source to the second target speed.   
     
     
         15 . The computer implemented method of  claim 14 , wherein the speed threshold is based on a power threshold associated with the used power of the hybrid driveline. 
     
     
         16 . The computer implemented method of  claim 14 , wherein the speed threshold is determined based on a planing speed of the marine vessel. 
     
     
         17 . The computer implemented method of  claim 14 , further comprising:
 responsive to the wanted speed being below the speed threshold:   determining, by the processing circuitry, the first target speed to be at the wanted speed, and   determining, by the processing circuitry, the second target speed to be lower than the wanted speed.   
     
     
         18 . The computer implemented method of  claim 16 , further comprising:
 responsive to the wanted speed being above the speed threshold:   determining, by the processing circuitry, the first target speed to be lower than the wanted speed, and   determining, by the processing circuitry, the second target speed to be at the wanted speed.   
     
     
         19 . A computer program product comprising program code for performing, when executed by processing circuitry, the method of  claim 14 . 
     
     
         20 . A non-transitory computer-readable storage medium comprising instructions, which when executed by processing circuitry, cause the processing circuitry to perform the method of  claim 14 .