This is a brief description of the Equivalent Consumption Minimization Strategy (ECMS) code provided by Dr. Emrah Bayrak. The code can be downloaded here. The entrance file is fMPG.m.

Description of files

Below are descriptions of all files. For instructions on the modification, see the next section.

Files that need modification

• fMPG.m: This file takes in a gear_ratio (scalar) and a drive cycle name (string). To run the code, please prepare a drive cycle as a .mat file. This file should contain a matrix with variable name cyc_mph. The matrix has two columns: the first column has time steps (starting with 0), the second has the corresponding velocity values. The outputs are the optimal fuel consumption (gram) and MPG. The final state of charge (SOC) can be found from the variable SOC_fin. Desired SOC is set by SOC_des.

• hybrid_ECMS_ATC.m: Main file for the ECMS algorithm. The function outputs MPG, final SOC (SOC_fin), fuel consumption along time (FC_plot), SOC along time (SOC_plot), Mode shifting along time (Mode_plot, obsolete for single mode powertrain), time array (t_array), and whether the powertrain mode is feasible for the given drive cycle (ISfeas).

• hev_vehicle.m: Defines all vehicle parameters. You will need to modify this file for your vehicle.

Files that do not need modification

• hev_finaldrive.m: Defines the transmission torque and speed based on vehicle torque and speed.

• hev_transmission.m: Defines motor speed and torques based on transmission and engine speed and torques. This file is for power-split powertrain only.

• paretoset.m: Auxiliary file for finding the pareto optimal data points from a data set.

• PoP_battery.m: Defines battery power consumption based on battery voltage and current.

• PoP_engine.m: Defines engine fuel consumption and max torque.

• PoP_motor42.m: Defines motor power consumption and max torque.

Instruction on modifications

On line 63-64, 126-128 of fMPG.m, and line 70-72 of hybrid_ECMS_ATC.m, you need to complete the code for computing the motor torque and speed from engine and transmission torque and speed.

For a parallel hybrid powertrain, the engine, motor, and the transmission share the same angular speed. The torque from the transmission is split between the engine and the motor.

For power-split powertrain, the relationship is more involving. You can find a discussion from this paper.