Compression Ignition(CI) Engine Ignition Switch Profile functionality

1 view (last 30 days)
In Conventional Vehicle Reference Application -> Logitudinal driver -> Longitudinal driver, there is an Ignition switch profile. The Ignition switch is high only for one second (image attached). How exactly does this influence the model? The ignition is off but the vehicle still runs?
How does the engine start- stop logic work (image attached)? Can you elaborate on it?

Accepted Answer

MathWorks Support Team
MathWorks Support Team on 21 Nov 2022
The ignition switch profile can be found in the Conventional Vehicle Reference Application example.  
  1. How exactly does this influence the model? The ignition is off but the vehicle still runs? 
The ignition switch is able to turn off the engine by setting throttle to 1 provided we turn on the ignition switch. Here is the example by turning off the engine at t=30s and restart the engine at t=60s: 
- Assume the virtual vehicle is automatically turned on while starting the simulation.  
- The vehicle starts at t=20s according to pre-set driving cycle profile 
- Modify signal value of ‘Ignition Switch Profile’ to 1 during t=30 to 60s as shown in picture below 
- Turn on the engine again by modifying Ignition Switch signal to 0 as indicated in the velocity profile.
Please note that when you set 'ignition switch' signal to 1 after the vehicle start, the speed (RPM) of the engine naturally converged to 0 after a while. It is recommended to add some friction in your model to make sure that once throttle is 1 the engine slows down to zero. The stall speed must also be set to zero or be negative as the simulation might error out once it goes below stall speed once engine is turned off.
2. How does the engine start- stop logic work (image attached)? Can you elaborate on it?
The engine stop-start control works as follows. When driver drives through many congested traffics, e.g, urban areas, the start-stop function works given the following conditions are met:
  • The Engine Stop-Start (ESS) function is enabled -> 'EngStopStartEnable' is set as ‘true’;
  • The engine cuts off fueling -> 'CatLightOffTime' > 0(or other user-defined constant);
  • The clutch is depressed -> 'EngStopTime' > 5 (or other user-defined constant);
Then, the car will stop the engine and set signals ‘TrqCmdISC’ and ‘InjPw’ in order to stop the engine temporarily. 
Overall, the reference model illustrates the functionality of turning the engine off by using ‘Ignition Switch Profile’ in Longitudinal driver or enable ESS (the ESS is enabled by default).

More Answers (0)

Categories

Find more on Green Vehicles in Help Center and File Exchange

Products


Release

R2022a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!