Week-4 Challenge WOT Condition Part-2

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

Powertrain Blockset provides two types of combustion engine models: mapped and dynamic.

Mapped engines, motor or generator :

this 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, motor or generator:

this decompose the behavior into individual component models that account for eg 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.

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.

Model type change:

Open HEV reference application>passenger car>rightclick on engine>variant>override variant> choose mapped or dynamic(if mapped is not mention its default property is dynamic)

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

What is miles per gallon (US mpg)?

US miles per gallon is a unit of fuel economy in US Customary Units. US miles per gallon is calculated as the number of miles traveled per US gallon (not to be confused with Imperial gallon). The symbol for US miles per gallon is US mpg.

the mpg calculation is based on three parameters for the HEV reference application are vehicle speed , fuel flow and battery power.

primary formulae for millage is miles per gallon (mpg)=(miles driven in miles) /(gallons consumed)

here we are simulating hybrid vehicle ie..it is combination of electric power (electricity) + mechanical power(fuel's)

step1: battery power is converted to equivalent consumption in fuel units of kg/m3.

step2: actual fuel consumption is being added with battery power consumed in terms of kg/m3

step3: with overall fuel kg/m3 is converted to us gallon using standard multiplying factos

step4: vehicle speed is converted to miles driven by multiplying with suitable multiplying constant factor

step5. vehicle speed i.e miles driven is divided gallons consumed gives us the mpg.

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

WOT condition with change in wind velocity vs normal condition

here we can observe that current consumption has been increased due to increase in torque by electric motor and fuel consumption mpg got decreased due to increase wind resistance the force generated by electric motor is more.

the change in grade caused battery consumption to be used up more, and acceleration reached by vehicle is slightly reduced, in which torque got increased. Here the change in grade is loading the electric motor thereby and distance coverage is less due to forces acting on vehicle

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

two reference models (electric vehicle and hybrid electric vehicle)has been simulated with their default condition taken ftp profile as a base.

The main difference between a hybrid car and an electric car is that the hybrid combines an internal combustion engine and electric motor to send power to its wheels. However, the electric car draws power from a single source of the electric motor to propel the vehicle.

From the above graphs hybrid cars offer better fuel efficiency or longer distances/ranges, electric vehicles are still yet to reach that potential. That said, electric vehicles pollute lower emissions compared to hybrid cars who are dependent on an internal combustion engine.

here the current consumption is more in electric vehicle due to this mpg got increased. while in HEV the combination of motor and engine gave reduction in mpg.

As per market condition, pure electric vehicle costs more than hev and for pollution wise electric vehicle is leading in pollution free vehicle.