E-trailer

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This page provides the steps on how to model e-trailer project from e-Traction. The e-trailer project is a concept project from e-Traction in which e-trailer is a normal trailer that has an electric motor mounted to one of its axle.
The ultimate goal of this project is to increase energy efficiency [kWh/km], which leads to reducing operating cost.

Creating the model

The model is split into four different areas. Those are:

  • Test scenario (Driving cycle)
  • ECU
  • Plant model (Parallel Hybrid vehicle powertrain component)
  • Driver (Vehicle driver model)

Test scenario

  • Insert the Test_scenario component to (SIMarchitect) workspace, this component can be found under the Test Scenario in SIMarchitect Library.


Test_scenario

ECU

A simple control algorithm has been developed and implemented into the e - trailer model in order to control the energy distribution between the Internal Combustion Engine and the Electric Machine. The control algorithm used the accelerator and brake pedal position to determine the demanded torque by the vehicle so that it can follow the desired driving cycle. The amount of throttle and brake required was calculated by the driver model. The required gear number for a certain moment was calculated by the gear shift logic that located inside the driver model. The electric machine is used together with the I.C.E. to achieve the demanded torque when the ECU determined that the demanded torque is above the maximum capability of what the engine can supply. If the state of charge of the battery is lower than the minimum charge value, the electric machine will be used as a generator to charge the battery during braking motion. The electric machine is also used to brake the vehicle when possible, however, mechanical brakes will be used when the braking torque from the electric machine is not sufficient.

To create the ECU subsystem:

  • First insert an empty_area component to (SIMarchitect) workspace, this component can be found under the modeling tools below SIMarchitect general library.
  • Second, rename this empty_area componenent into ECU.
  • Third, delete the in and out ports inside the ECU subsystem as it is shown in the figure below.


empty_area


  • Fourth, insert the ECU module to the ECU subsytem. The ECU module and its parameter file can be downloaded (insert ECU module and its parameter).
  • Fifth, delete the extra port in the sub_connector (green box in the figure below) by double-clicking the sub_connector and change the number of inputs into 1 to delete this extra port.


e - trailer ECU

Plant model

To create the Plant_model subsystem:

  • First insert an empty_area component to (SIMarchitect) workspace, this component can be found under the modeling tools below SIMarchitect general library.
  • Second, rename this empty_area component into Plant_model.
  • Third, delete the in and out ports inside the Plant_model subsystem as it is shown in the empty_area figure above.
  • Fourth, insert the components listed below to the Plant_model subsystem and order them as it is shown in the figure below.


All of the components can be found in the downloaded SIMarchitect library, under component library → automotive → HDH - HiLS → chassis or powertrain and they are all color coded
The components used for the truck group:

  • Internal Combustion Engine
  • Clutch
  • Mechanical connection
  • Transmission
  • Final gear
  • Chassis

The components used for the trailer group:

  • Battery
  • Electric machine
  • Electrical auxiliary system


  • Fifth, change the tag visibility setting (from local to global) of the goto tag from the Final_gear_module, Electrical_aux_system_module and Electric_machine_module. Tag visibility setting can be found by double-clicking the goto tag from each of the mentioned modules.


e - trailer plant model.


  • Fifth, add three (3) extra ports in the sub_connector, this can be done by double-clicking the sub_connector and change the number of input to 12.

Subsystems

Battery current subsystem Notice that there are 2 extra subsystems located at the right-hand side of the e - trailer plant model figure.
The Battery current subsystem is created as follows:

  • First, locate the from tag of Electric machine module and Electrical auxiliary system and copy-paste it in the workspace.
  • Second, insert two (2) Bus Selector(s) and connect it to each tag.
  • Third, double-click the first bus selector, remove signal1 and signal2 under the selected signals inside the bus selector prompt and select Electric_machine_electrical_fb__output.phys_current_A under the Electric_machine_sensor
  • Fourth, double-click the second bus selector, remove signal1 and signal2 under the selected signals inside the bus selector prompt and select Electrical_aux_electrical_fb_output.phys_current_A under the Electrical_aux_sensor.
  • Fifth, insert sum component from SIMULINK library browser to add the selected signals.
  • Sixth, create a subsystem out of the components that just create the previous five steps. This can be done by block all of the created components then press ctrl+g to create a subsystem.
Battery current subsystem.


Combine torque and inertia subsystem The Combine torque and inertia subsystem is created as follows:

  • First, locate the from tag of Electric_machine_module and Final_gear_module and copy-paste it in the workspace as two sets (2x Electric_machine_module and 2x Final_gear_module).
  • Second, insert two (4) Bus Selector(s) and connect it to each tag.
  • Third, double-click the first bus selector, remove signal1 and signal2 under the selected signals inside the bus selector prompt and select Electric_machine_mechanical_output.phys_torque_Nm under the Electric_machine_mechanical_output .
  • Fourth, double-click the second bus selector, remove signal1 and signal2 under the selected signals inside the bus selector prompt and select Final_gear_mechanical_output.phys_torque_Nm under the Final_gear_mechanical_output.
  • Fifth, insert sum component from SIMULINK library browser to add the selected signals from the previous two (2) steps.
  • Sixth, double-click the third bus selector, remove signal1 and signal2 under the selected signals inside the bus selector prompt and select Electric_machine_mechanical_output.phys_inertia_kgm2 under the Electric_machine_mechanical_output.
  • Seventh, double-click the fourth bus selector, remove signal1 and signal2 under the selected signals inside the bus selector prompt and select Final_gear_mechanical_output.phys_inertia_kgm2 under the Final_gear_mechanical_output.
  • Eighth, insert sum component from SIMULINK library browser to add the selected signals from the previous (2) steps.
  • Ninth, create a subsystem out of the components that just create the previous eight steps. This can be done by block all of the created components then press ctrl+g to create a subsystem.
Combine torque and inertia subsystem.


Next, connect the output ports of the created subsystems to the sub_connector, to do this:

  • First, insert three (3) goto tag to the workspace
  • Second, rename them as you wish but for this case rename it into A, B and C accordingly.
  • Third, rename the signal label into Battery_Current_input for tag A, Total_vehicle_torque for tag B and Total_vehicle_inertia for tag C.
  • Fourth, insert the from tag out of each goto tag.
  • Fifth, connect each from tag to the empty port of sub_connector.

Driver

The e-trailer project use manual transmission, therefore the driver manual module will be used as the driver model.
To create driver subsystem:

  • First insert an empty_area component to (SIMarchitect) workspace, this component can be found under the modeling tools below SIMarchitect general library
  • Second, rename this empty_area component into Driver.
  • Third, delete the in and out ports inside the Driver subsystem as it is shown in the empty_area figure above.
  • Fourth, insert the vehicle driver manual from the SIMarchitect library to the Driver subsystem.
Driver area

Assigning signal inputs

ECU

To assign the signal input for ECU module:

  • First, double-click the black box on top of the module to show the bus selector prompt.
  • Second, remove none from the selected signals area, located on the right-hand side of the bus selector prompt.
  • Third, follow the table below to assign signals to each component module.


Note: Be aware that the signal shown in the bus selector prompt might not be in the same order as it is shown in the table below.
The signals should be assigned according to the order shown in the table below. Otherwise, the simulation will give an error and not run.


Input signal Located under Signal label
Accelerator pedal position Driver vehicle_driver_manual_module → Driver Drv_AccPedl_Rt
Brake pedal position Drv_BrkPedl_Rt
Drive cycle reference speed Drivecycle_RefSpeed_mps
Clutch pedal position Drv_CluPedl_Rt
Requested gear number Drv_nrGearReq
Actual engine speed Plant_model ICE_module → ICE_sensor Eng_nAct_radps
Crankshaft torque Eng_tqCrkSftAct_Nm
Indicated torque Eng_tqindAct_Nm
Engine oil temperature Eng_tOilAct_K
Battery output current Battery_module → Battery_sensor Batt_iAct_A
Battery output voltage Batt_uAct_V
State of charge Batt_socAct_Rt
Battery temperature Batt_tAct_K
Clutch disengaged or not Clutch_module → Clutch_sensor Clu_flgConnected_B
Electric machine output torque Electric_machine_module → Electric_machine_sensor ElecMac_tqAct_Nm
Electric machine output speed ElecMac_nAct_radps
Electric machine output current ElecMac_iAct_A
Electric machine output temperature ElecMac_tAct_K
Transmission output speed Transmission_module → Transmission_sensor Transm_nOutAct_radps
Transmission gear number Transm_nrGearAct
Clutch lock Transm_flgConnected_B
Transmission input speed Transm_nInAct_radps
Vehicle velocity Chassis_module → Chassis_sensor Chassis_vVehAct_mps
Wheel speed Chassis_nWheelAct_radps
Vehicle mass Chassis_massVehAct_kg
Road slope Chassis_slopeRoad_rad
Auxiliary system output current Electrical_aux_system_module → Electrical_aux_sensor Aux_iAct_A


Plant model

To assign the signal input for each component module:

  • First, double-click the black box on top of the module to show the bus selector prompt.
  • Second, remove none from the selected signals area, located on the right-hand side of the bus selector prompt.
  • Third, follow the table below to assign signals to each component module.


Note: Be aware that the signal shown in the bus selector prompt might not be in the same order as it is shown in the table below.
The signals should be assigned according to the order shown in the table below. Otherwise, the simulation will give an error and not run.


ICE module

Input signal Located under Signal label
Requested engine speed ECU ECU_module → cmd Eng_nReq_radps
Switch Speed / torque control Eng_flgReqSwitch_B
Requested engine torque Eng_tqReq_Nm
Exhaust brake ON / OFF Eng_flgExhaustBrake_B
Engine ON / OFF Eng_flgonoff_B
Starter motor ON / OFF Eng_flgstrtrReq_B
Fuel cut off Eng_flgFuelCut_B
Engine rotational speed Plant_model Clutch_module → clutch_mechanical_fb_output phys_speed_radps


Clutch module

Input signal Located under Signal label
Requested clutch pedal position ECU ECU_module → cmd Clu_ratReq_B
Clutch torque input plant_model ICE_module → ICE_mechanical output phys_torque_Nm
Clutch inertia input phys_inertia_kgm2
Clutch rotational speed input Mechanical_connection_module → MC_mechanical_fb_output1 phys_speed_radps


Mechanical connection module

Input signal Located under Signal label
Mechanical connection torque input 1 plant_model Clutch_module → clutch_mechanical_output phys_torque_Nm
Mechanical connection inertia input 1 phys_inertia_kgm2
Mechanical connection torque input 2 one - one
Mechanical connection inertia input 2 one
Mechanical connection feedback input plant_model Transmission_module → Transmission_mechanical_fb_output phys_speed_radps


Transmission module

Input signal Located under Signal label
Requested gear number ECU ECU_module → cmd Transm_nrGearReq
Transmission torque input plant_model Mechanical_connection_module → MC_mechanical_output phys_torque_Nm
Transmission inertia input phys_inertia_kgm2
Transmission rotational speed input Final_gear_module → Final_gear_mechanical fb output phys_speed_radps


Final gear module

Input signal Located under Signal label
Final gear torque input plant_model Transmission_module → Transmission_mechanical_output phys_torque_Nm
Final gear inertia input phys_inertia_kgm2
Final gear rotational speed input Chassis_module → Chassis_mechanical_fb_output phys_speed_radps


Chassis module

Input signal Located under Signal label
Requested chassis brake torque ECU ECU_module → cmd Chassis_tqBrake_Nm
Chassis torque input plant_model - Total_vehicle_torque
Chassis inertia input Total_vehicle_inertia
Drivecycle slope Test_scenario Test_scenario drivecycle_time_slope


Battery module

Input signal Located under Signal label
Battery current input plant_model plant_model battery_Current_Input
Battery Actual cooling flow ECU ECU_module → cmd Batt_flowActCooling_kgps


Electric machine module

Input signal Located under Signal label
Requested electric machine speed ECU ECU_module → cmd ElecMac_nReq_radps
Switch speed / torque control ElecMac_flgReqSwitch_B
Requested electric machine torque ElecMac_tqReq_Nm
Electric machine actual cooling flow ElecMac_flowActCooling_kgps
Electric machine voltage input plant_model Battery_module → Battery_electrical output phys_voltage_V
Electric machine rotational speed input Mechanical_connection_module → MC_mechanical_join_output2 phys_speed_radps


Electrical aux system module

Input signal Located under Signal label
Requested power ECU ECU_module → cmd Aux_pwrElecReq_W
Voltage input plant_model Battery_module → Battery_electrical_output phys_voltage_V


Driver

To assign the signal input for Vehicle driver module:

  • First, double-click the black box on top of the module to show the bus selector prompt.
  • Second, remove none from the selected signals area, located on the right-hand side of the bus selector prompt.
  • Third, follow the table below to assign signals to each component module.


Note: Be aware that the signal shown in the bus selector prompt might not be in the same order as it is shown in the table below.
The signals should be assigned according to the order shown in the table below. Otherwise, the simulation will give an error and not run.


Input signal Located under Signal label
Actual vehicle velocity plant_model Chassis_module → Chassis_sensor Chassis_vVehAct_mps
Transmission input speed Transmission_module → Transmission_sensor Transm_nInAct_radps
Transmission actual gear number Transm_nrGearAct
Clutch disengaged or not Clutch_module → clutch_sensor Clu_flgConnected_B
Accelerator pedal rate Driver vehicle_driver_manual_module → Driver Drv_AccPedl_Rt
Drive cycle time and speed Test_scenario Test_scenario drivecycle_time_speed

Simulation settings

The simulation settings for e-trailer project:

Settings Value
Time 1800 [s]
Fixed - step size 0.01
Solver type ode3 (Bogacki - shampine)

Running the simulation

Use this parameter files for the e - trailer simulation.
Before running the simulation, load the downloaded parameter into the created e - trailer project, this can be done by double-clicking the parameter setting button located on the top level layout of SIMarchitect and select the directory of where does the downloaded parameter file is located.
The sequence of running the simulation:

  • First, run parameter_main m.file
  • Second, choose the desired output results in the Output Selector block
  • Third, run the simulation
  • Fourth, plot the results using Results Plot GUI block

The output from each individual module can be plotted using the Results Plot GUI.

Contact

For more information regarding the specification of the battery and electric motor please contact e-Traction

e-Traction Europe B.V.
Watermanstraat 40
7324 AH Apeldoorn
The Netherlands
Phone: +31 55 52 11111
E-mail: info@e-traction.com

Simulation result

Based on the simulation result, the comparison in terms of energy consumption [kWh/km] can be made.
The energy consumption was calculated by using the following equation:

Energyconsumptioneq.png

with:

  • Diesel calorific value of 45.6 [MJ/kg].
  • Total driving time of 1800 seconds.
  • Total driving distance of 20 km.
Vehicle configurations Average fuel consumption [kg/s] Average fuel consumption [L/km] Average energy consumption [kWh/km]
Electric motor is in-operational 0.0058 0.6328 6.68
Electric motor is operational 0.0053 0.5782 6.09

The improvement in average energy consumption was calculated to be 8.62 %

The fuel consumption comparison plot can be seen in the figure below. The green circles indicate that the fuel consumption is higher when the electric motor is in-operational.

Fuel consumption comparison