2. Plant model: Driver & Environment
The Driver and Environment Xcos models are relatively simple. The Driver model outputs the profile in time of the accelerator and brake pedals position. The Environment model outputs the time profile of the road slope (gradient).
The decision on what profile is used for the simulation is done by setting the right value for the parameter DrvgMod_z_C. This parameters decides the simulation scenario, by switching through a multiport switch (Dynamic index).
Image: Driver and Environment – Xcos block diagram
As you can see, there are no inputs into the Driver and Environment model. The parameters and outputs are defined in the tables below.
Parameters
| Name | Value | Description |
| DrvgMod_z_C | 1 | Sets the simulation scenario: 1 – Acceleration, 2 – Braking, 3 – Hill climb |
Outputs
| Name | Value | Description |
| AccrPedlPosn_prc | – | Acceleration pedal position in [%] |
| BrkPedlPosn_prc | – | Brake pedal position in [%] |
| EnvRoadSlop_prc | – | Road slope (gradient) in [%] |
In order to avoid high jumps in the signal, which can not happen in a real driving situation, all outputs are filtered using a first-order transfer function (low-pass filter). The outputs are also fed into global GOTO blocks in order to be saved in the Scilab workspace.
2.1 Full acceleration
The first driving mode for the simulation is a full acceleration scenario.
Image: Driver and Environment full acceleration – Xcos block diagram
The accelerator, brake pedal and road slope are generated into a signal builder block, Sigbuilder. The parameters are defined in the Scilab workspace. All three signals are the multiplexed using a MUX block. The reason for multiplexation is just to avoid having to use multiple Dynamic index blocks, one for each signal.
Parameters
| Name | Value | Description |
| AccrPedlPosnProfTi1_s_X | [0;1;1.01;tf] | Acceleration pedal position time profile axis |
| AccrPedlPosnProf1_prc_Z | [0;0;100;100] | Acceleration pedal position time profile map |
| BrkPedlPosnProfTi1_s_X | [0;tf] | Brake pedal position time profile axis |
| BrkrPedlPosnProf1_prc_Z | [0;0] | Brake pedal position time profile map |
| EnvRoadSlopProfTi1_s_X | [0;tf] | Road slope (gradient) time profile axis |
| EnvRoadSlopProf1_prc_Z | [0;0] | Road slope (gradient) time profile map |
2.2 Braking
The Xcos block model for the braking scenario is the same as for the acceleration scenario. The only difference is in the parameters setup.
Parameters
| Name | Value | Description |
| AccrPedlPosnProfTi2_s_X | [0;5;10;15;20;40;45;tf] | Acceleration pedal position time profile axis |
| AccrPedlPosnProf2_prc_Z | [0;0;60;60;0;0;40;40] | Acceleration pedal position time profile map |
| BrkPedlPosnProfTi2_s_X | [0;20;25;35;40;tf] | Brake pedal position time profile axis |
| BrkrPedlPosnProf2_prc_Z | [0;0;35;35;0;0] | Brake pedal position time profile map |
| EnvRoadSlopProfTi2_s_X | [0;tf] | Road slope (gradient) time profile axis |
| EnvRoadSlopProf2_prc_Z | [0;0] | Road slope (gradient) time profile map |
2.3 Hill climb
The Xcos block model for the hill climb scenario is the same as for the acceleration scenario. The only difference is in the parameters setup.
Parameters
| Name | Value | Description |
| AccrPedlPosnProfTi3_s_X | [0;1;2;10;30;tf] | Acceleration pedal position time profile axis |
| AccrPedlPosnProf3_prc_Z | [0;0;30;30;20;20] | Acceleration pedal position time profile map |
| BrkPedlPosnProfTi3_s_X | [0;tf] | Brake pedal position time profile axis |
| BrkrPedlPosnProf3_prc_Z | [0;0] | Brake pedal position time profile map |
| EnvRoadSlopProfTi3_s_X | [0;5;10;10.01;tf] | Road slope (gradient) time profile axis |
| EnvRoadSlopProf3_prc_Z | [0;0;0;12;12] | Road slope (gradient) time profile map |
Mirsad
Hello,
I created this model in Simulink. Everything is same with this model. When I run at full acceleration case, engine speed and turbine speed is not same as you shared. I think it is also reasonable. Because only parameter affecting engine speed is ımpeller torque and doesn’t change based on gear.
Saulnier
Hi,
Thank you for this very instructive modeling. I tried to recreate it with another car but I have different results, especially for the engine torque.
Indeed, the impeller torque become as important as the driver requested torque (the one obtained from the engine map) and I obtain a zero engine torque in output (substraction of the impeller torque from the driver requested torque in the engine plant).
Is it physically right ?
I thank you in advance for your answer,
Sincerely
A.Saulnier