Week-3 Challenge: ADVISOR Tool

Answer 1:- ADVISOR (Advance Vehicle Simulator):

ADVISOR, NREL's Advanced Vehicle Simulator, is a set of model, data and script text files for use with Matlab and Simulink. It is designed for rapid analysis of the performance and fuel economy of conventional, electric and hybrid vehicles. ADVISOR also provides a backbone for the detailed simulation and analysis of user defined drivetrain components, a starting point of verified vehicle data and algorithms from which to take full advantage of the modeling flexibility of simulink and analytic power of MATLAB.

Benefit of ADVISOR are:

• To estimate the fuel economy of vehicles that have not yet been built.
• To learn about how conventional, hybrid or electric vehicles use (and lose) energy throughout their drivetrains.
• To compare relative tailpipe emissions produced on a number of cycles.
• To evaluate an energy management strategy for your hybrid vehicle's fuel converter.
• To optimize the gear ratios in your transmission to minimize fuel use or maximize performance, etc.

The Model of ADVISOR are:

• Mostly empirical, relying on drivetrain component input/output relationships measured in the laboratory.
• Quasi-static, using data collected in steady state (for example, constant torque and speed) tests and correcting them for transient effects such as the rotational inertia of drivetrain components.

Considering the case for an typical EV, let's simulate EV_ defaults_in, an electric vehicle with following specifications:

In the above example, a battery electric vehicle is modelled with following specifications:

Energy storage : Lead acid battery with 25 modules having 308V as nominal voltage with 0.92 motor efficiency.

Motor : AC induction motor with 75KW

Transmission: manual

Drive: front wheel drive

Cargo mass: 500kg

Next, we input the drive cycle called CYC_FTP which is 17.7 km long in distance. Hence in order to drain the battery completely to SOC =0% for calculating the range of vehicle, 4 drive cycles are repeated, so that vehicle will travel 70.8km in total and we can find out at what distance the SOC is 0.

In the above figure, first plot shows the drive cycle for which vehicle has travelled, the second plot shows the SOC fall with time, the third and the fourth graph show the power output according to the throttle condition.

Hence, after running the simulation, we can see that, the SOC becomes 0 offer approximately 2.5 drive cycles. As shown at the right hand side, the distance travelled by vehicle is 41.4km. Hence the vehicle cannot travel 45km in a single charge.

Answer 2: In this case the same default conditions are taken that are initiate in question 1 and battery capacity will be changed for accelerating the vehicle that will increase the vehicle distance travel km.

-Increasing the battery capacity of vehicle

So, in order to achieve a range of 45km, 3 more modules of batteries have been added making the total modules to 28 and nominal voltage to 345V.

In the above image, the vehicle travels a distance of 46.5km. Hence 28 number of battery modules are sufficient to satisfy a range of 45km according the problem description.

Answer 3:- Following is the model of Toyota Prius parallel hybrid vehicle. It uses battery and an IC engine to power the wheels. As can see from the figure, the differential is connected to the motor and it is also connected to an IC engine via a device called as a power split device. Power split splits the power according to the throttle demands keeping the engine in maximum efficiency zone, providing additional power via battery and engine during aggressive conditions, charging the battery via a generator during conditions such as regenerative braking and preserving the energy efficiently.

Vehicle specifications:

Power produced by IC engine: 43KW with fuel convertor efficiency of 0.39

Battery capacity: NMH(Nickel Metal Hydride) batteries have been used with 40 modules producing a nominal voltage of 308V.

Generator( Regenerative): 15KW

Motor :Induction motor producing power of 15KW with 0.84 efficiency.

Transmission : CVT

Drive : front wheel drive

In order to perform the gradeability test, we keep the grade value constant and change the speed values to find out the maximum gradeability at an optimum speed simulating for 10s.

Hence the simulation is runner for gradeability test.

Following are the output results:

Case1:- Speed= 5mph (8kmph)

Gradeability=32.8%

Case2:- Speed=15mph(24.1kmph)

Gradeability=24.4%

Case3:- Speed=20mph(32.2kmph)

Gradeability=19.8%

Case4:- Speed=40mph(64.4kmph)

Gradeability=11.7%

Conclusion:

We can see that as the speed of vehicle increases, the gradeability decreases.

Hence they are inversely proportional.

SPEED	GRADEABILITY
5MPH	32.8%
15MPH	24.4%
20MPH	19.8%
40MPH	11.7%