Week-4 Challenge WOT Condition Part-2

Objective 1:- What is the difference between mapped and dynamic model of engine, motor and generator? How can you change model type?

Definition is based on IC engine example. 

Mapped:- Model uses a set of steady-state lookup tables to characterize engine performance.

The tables provide overall engine characteristics, including actual torque, fuel flow rate, BSFC, and engine-out exhaust emissions.

• If you have engine data from a dynamometer or a design tool like GT-POWER.

• For quasi steady-state engine simulations.

Dynamic:- Model decomposes the engine behavior into engine characteristics that are separated into lower-level components. By combining components in this way, the models capture the dynamic effects. 

• If you need a more detailed dynamic model and have component-level data.

• To analyze the impact of individual engine components on the overall performance.

Powertrain Blockset provides two types of combustion engine models: mapped and dynamic. Mapped engines represent macro engine behavior as a set of lookup tables (brake torque, fuel flow, air mass flow, exhaust temperature, efficiency, and emissions) as functions of commanded load and measured engine speed. Dynamic engines decompose engine behavior into individual component models that account for engine dynamics, most notably intake airflow and turbocharger dynamics.

You can switch between engine model types based on your application. Dynamic engine models are suitable for designing control, estimator, and diagnostic algorithms that depend on dynamic subsystem states, for example, in closed-loop AFR control algorithm development. Mapped engine models are suitable for analysis and design activities that do not require engine subsystem dynamic characteristics, for example, in engine and transmission powertrain matching analysis for fuel economy, emissions, and performance tradeoffs.

How we can change the MotGen Mapped to Dynamic & Vice cersa.

1)- Open The model in the Simulink

2)- Double click on the Passenger block.

3)- Then click on the Electric plant block.

4)- At the motor block right click to get variant option.

5)- By clicking variant we are getting two option, one no label mode active choice and second no is open in variant manager.

6)- Click on label mode active choice to changeover of Mapped to Dynamic and Dynamic to Mapped.

Go thorugh the image to understand this.

Objective 2:- How does the model calculate miles per gallon? Which factors are considered to model fuel flow? 

 MPG stands for miles per gallon and is used to show how far your car can travel for every gallon (or 4.55 litres) of fuel it uses. For example, if you own a car that returns 50mpg and its fuel tank only has one gallon of petrol or diesel in it, you’ll drive 50 miles before the car runs out of fuel.

Official fuel economy figures are calculated based on WLTP testing (which stands for Worldwide Harmonised Light Vehicle Test Procedure).

This is conducted in a lab to simulate real-world driving scenarios. If you’re interested in finding out the exact MPG your current car is achieving, the vast majority of new cars will give you a readout of its current MPG on the driver’s display or central infotainment system.

A higher MPG means less fuel is consumed as you’re driving. That means it’ll cost you less to run and (generally speaking) meaning your car is producing fewer emissions as it burns fuel more efficiently.

If you’re looking to improve your own MPG you can influence it with a few changes to your driving habits. Smoother acceleration and braking will help you get that figure up, for example.

Litres per 100km (l/100km) is the European standard for fuel consumption. It’s almost a reverse of MPG — the lower the number is better in this case.

For example, 1mpg is approximately the equivalent of 282.48 l/100km, with 1 l/100km the equivalent to 282mpg. A car achieving 40mpg would return about 7.06 l/100km.

Steps for workflow of fuel system in the model:-

Firstly go to Reference block then click click on performance calculation.

After clicking over performance calculation we got the workflow and calculation of MPG.

By this workflow we can understand the calculation procedure of MPG.

1)- Majorly in this diagram we have two inputs such as Vehicle speed and battery power.

2)- The vehicle speed input is in m/s which is converted into miles by multiplying with 0.000621371. before that we used integrator to make it meter only so easily we converted into miles.

1 meter (m) = 0.00062137 miles (mi).

3)- The vehicle speed input in m/sec which is converted into miles by multiplying by 0.000621371. in this configuration we have integrate this to convert m.sec to mtr then convert it into miles.

4)- This meter is multiplying by 100000 to convert it into mtr to 100km.Which helps us to calculate L/100km.

5)- Battery power which is in watt, converted into KW then convert it tino US EPA gallon by dividing it by 33.7 then devide by 3600 to get the value in sec and multiply it by 0.00378541 to get the value of cubic meter per gallon.

6)- The integrator value of cubic meter per gallon is multiply by 1000 to convert it into L.

7)- calculated L/100km and L will halp to calculate L/100KM.

Objective 3:- Run the HEV ReferenceApplication with WOT drive cycle. Change the grade and wind velocity in the environment block. Comment on the results.

In the above model we have chnaged some parameters like Driving cycle by selcting WOT with some parameters. Which shown below.

We can see the resultant graph of Trace & Actual velocity, Battery SOC, Battery current, Motor torque, Motor RPM and Fuel.

Now we have chnaged the grade and wind velocity by 6 & 12.

Now we are analysing the graph. 

Conclusion:- 

1)- Trace velocity is blue line and actual velocity is yellow line. But due to high grade and wind velocity and insufficient battery power we can't reach the trace velocity. As we know very well in HEV initally battery will work to run the model.

2)- Battery current is very much proptional to the velocity. As per increasing the velocity current increases even during deacceleration we got regenrative braking. battery current is in negative. so we can see by the result that HEV has very active in regenrative braking.

3)- The battery SOC keeps active during running, Acceleration, Deacceleration with good enough of SOC.

4)- Intially motor has started because of high intial torque so we got the Motor RPM. After that generator will take command to maintain SOC of the vehicle. Battery graph is in orange colour and generator graph is in yellow colour. Can't see the enine graph may be engine and generator grapg overlap to each other.

5)- Motor torque is in orange colour which act firstly because of high inital torque then enine take the command to pull it higher side. Meanwile generator is in negative direction yellow colour graph act in regenrative mode. 

Objective 4:- Keeping all other parameters same, compare the simulated results of hybrid and pure electric powertrains.

I have taken EV reference model where i have incorporated all data which i have used in HEV model which is shown in the image. 

Conclusion:-

After compairing the graph of both EV and HEV we have concluded some points which are discussing below.

1)- Firstly we have some parameters where we need to compare. Tha parameters are target & acual velocity, battery SOC, battery current, fuel, motor torque & motor RPM.

2)-  In the first graph we are analysing the target and the actual velocity where we are seeing in both the cases EV and HEV graph is almost same. As in EV it is actual behaviour but in HEV because in HEV motor is operating in this region. This is the intial region so in HEV motor operates in initial region so both the graph are almost same. 

3)- When we are seeing the battery SOC. Initally SOC of both the model issame bacause of their inital operating charactertics. But during and after deacceleration we can see the difference of SOC in both the model. In EV we have a very slight chnage of SOC in positive side like1-2% but in HEV during and after deacceleration we can see the higher side of SOC which is almost 10-15%.

4)- When we are seeing the battery current so initally battery current is very high approx 500amp in HEV model offcource initally running through motor. After some time current decreses to 200 amp then during deacceleration we get negative current which shows high active of regenrative braking in HEV model as compare to EV. At EV model we get 220amps current and during deacceleration we get low current also for very low time. 

5)- Motor torque and speed are very fluctuating in HEV model as compare to EV where as EV has very smooth operation. Also the peak RPM of the model is high in HEV model. These things shows the battery power which has in EV model as compare to HEV.

6)- When we are talking about fuel economy then offcource EV is high efficient as compare to HEV.