design&evaluation of phev powertrain

HYBRID ELECTRIC TRANSPORT

SATYAJEET UDAVANT PAGE NO 1

PROJECT REPORT

HYBRID ELECTRIC TRANSPORTATION

ME 50105

DESIGN AND EVALUATION OF PLUG-IN HYBRID

ELECTRIC VEHICLE (PHEV) POWERTRAIN

SATYAJEET UDAVANT

IUPUI, INDIANAPOLIS

SUBMISSION: MAY 1, 2016



Abstract:

Hybrid technology is an emerging and promising field of sustainable future in

especially automobile industry. There are various types of powertrain configuration

possible. These different possibilities give opportunity to work on various aspects of

automobile as per ones need. In recent years hybrid technology has taken a good grip and

many companies are embracing this technology as its supportive to environment with zero

emissions. In the following project I am using a Parallel Pretrans PHEV 2 wheel drive

midsize car. For simulation purposes, a software named Autonomie, is used. The focus of

this project is in two main areas.

1. Increase in efficiency, better performance fuel economy, and battery aspects among

the least. Varying a sect of parameters this can be achieved.

2. To give a comparative study of the various powertrain configuration.

After completing more than 70 simulations, I came to a conclusion and the report explores

the same. Most of the simulations were invalid as the configurations at times were absurd

or the specifications were not within the permissible limits. For most of the valid

simulations a base model was set and then changing a few parameters above mentioned

goals were achieved. A final model was set to compare the achieved results with that of

the base model. In between the other simulations were used to give a comparative study.

Analysis was made using the various plots of State of charge, Fuel consumption, fuel rate,

driver demand of acceleration, power out, power in, energy out, energy in, both for engine

and motor, and other battery performance. Simulations for Urban Dynamometer Driving

Schedule (UDDS) and HWFET rating for highway driving cycle were made.



Objective:

The primary objective of this report is to set a vehicle model/configuration and while

changing the various parameters obtain better fuel economy, better performance. Design

and optimization of component sizes. Design of energy management algorithm for the

powertrain. Use of Autonomie simulation software to build the model. Analyze the

performances of energy management algorithm. Result discussion is performed at the end

of the report. With these objectives in mind, I hope this report will serve as an example for

research and analysis in above mentioned aspect of Hybrid technology. Two different

approaches are made to achieve the desired goal. Varying the parameters simulations are

performed and a comparison is made between the Urban Driving Dynamometer Schedule

(UDDS) and Highway fuel Efficiency Test (HWFET) rating of the hybrid car. Acceleration

performance and gradeability is also considered while performing the simulation.

Literature review:

Hybrid Philosophy:

1. Operate electric motor first (less emissions/less fuel consumed).

2. Add gasoline engine only when needed.

3. Operate gas engine at the best rpm and throttle setting, that is, operate on minimum

fuel consumption line in engine map.[1]

Hybrid cars have many modes of operations and so there are many powertrain

configurations possible. Based on Drivetrain, they can be classified as:

Series- Hybrid electric drivetrain.

Parallel- Hybrid electric drivetrain.

Series-Parallel electric drivetrain.

There are different types of Hybrid cars:

Plug-in hybrid car.

Electric cars

Fuel-cell hybrid cars

Solar powered cars etc



For the purpose of this project Parallel Pretrans PHEV Autotrans 2-wheeldrive midsize

car is considered.

Fig [1] - Parallel Pretrans PHEV

Here, as shown in the figure both the engine and the torque are modified in the

transmission. However the engine and motor are to have the same speed range. A PHEV

is a drivetrain in which engine supplies its mechanical power directly to driven wheels.

Here IC Engine is supported by the Electric motor which is mechanically coupled to the

driveline.[2]

Advantages of Parallel driveline over Series driveline are:

Both engine and motor directly supply torques. Its compact. Traction motor is smaller than

in series.



Batteries:

The lithium batteries are of following types:

• Lithium polymer batteries • Lithium ion batteries

Battery is defined with its specifications and properties:

• specific energy • energy density • specific power • typical voltages

• amp hour efficiency • energy efficiency • commercial availability

• cost, operating temperatures • self-discharge rates • number of life cycles

Autonomie has been designed to be useful as a single tool in all of the different phases of

Model Based Design of the Vehicle Development Process (VDP). Model Based Design is

a math-based visual method for designing complex control systems. It is being used

successfully in many motion control, industrial, robotics, aerospace, and automotive

applications. It provides an efficient methodology that includes four key elements in the

development process which are as follows: modeling a plant (from first principles or

system identification), synthesizing and analyzing a controller for the plant, simulating the

plant and controller together, and programming/deploying the controller. Model Based

Design integrates all these multiple phases. It provides a common framework for

communication throughout the entire design process.[3]

Fig[2]- Sample of user

interface of Autoonmie

Simulation Software.



Simulation:

A total of around 70 simulations were made to learn and understand the various

aspects of the software autonomie. Most of the time with absurd results and the invalid

configurations the simulation was a disaster but failures taught the right way to use the

system. With the following parameter as base model, model was simulated for UDDS cycle

and HWFET cycle.

Parameters:

Vehicle model- Autotrans PHEV Pretrans 2-WheelDrive midsize vehicle.

Honda Accord (chassis and final drive)

Fig[3] model setup –base model

Base model includes: Motor of size, 34 kw. Engine size considered is 76 kw. Wheel used is R17

with aspect ratio 235/35. Drag Coefficient is 0.3 and frontal area is 2.275m2 .



Simulation result:

Simulation results describe the results in four columns UDDS, HWFET, acceleration and

gradeability. Important figures marked are described here.

Fuel Economy: 106 UDDS- 107 HWFET

Final SOC: 80.81 UDDS – 75.89 HWFET

Here you can see that the Final SOC of UDDS is more than HWEFT. A logical explanation

to this is regenerative braking. Because in urban driving a car has to stop and start

frequently. Due to this frequent brakes need to apply which generates energy and is stored

in battery. UDDS cycle is different than HWFET because of urban traffic and signal stops.



Following three graphs describes the following in respective manner:

1. Engine plant fuel consumption. Green line steeps early than blue as it represents the

HWFET cycle were engine is more utilized highway. As motors are more used in

urban cycle the blue line in graph raises gradually.

2. This describes the fuel rate. With the same explanation as above.

3. Torque output is described in graph 3.



Following graph describes power output of the motor. Blue line describes the urban cycle

as the alternative high peaks in blue line represents the frequent use of motor.

State of charge of the battery pack is depicted in the following graph.



The energy balance and the energy losses for the fuel efficient engine are as shown below:

Energy flow of the car is represented by the red and blue arrows , size of the arrow is with

respect to the amount of energy transferred. Energy generated from regenerative is storedin

battery.



Final model simulation details;

Changes in first model:

Final model includes:

Motor of size, 40 kw.

Engine size considered is 82 kw.

Wheel used is R18 with aspect ratio 235/35.

Drag Coefficient is 0.27 and frontal area is 2.0 m2 .



Simulation results:

1. Engine power output

2. Engine torque output

3. Fuel Consumption



1. Battery Energy output

2. Battery power out

3. Battery State of Charge

Green line steeps early than blue as it represents the HWFET cycle were engine is more

utilized highway. As motors are more used in urban cycle the blue line in graph raises

gradually



For simulation 2:

UDDS cycle The energy balance and the energy losses for the fuel efficient engine are as

shown below:

Energy flow of the car is represented by the red and blue arrows , size of the arrow is with

respect to the amount of energy transferred. Energy generated from regenerative is stored

in battery



Comparing the two models:

Fig[4] comparative table for the model parameter



BASE MODEL: Vehicle Propulsion Architecture.



This figure gives the comparison between the Acceleration and Gradebility between the

two models under consideration.

Acceleration performance is improved from 10.4 to 11.7

Fuel Economy of the first model is 10.23 and that of the final model is 13.39



MODEL #1

MODEL #2



Following is the comparison between the UDDS and HWFET cycle of Initial and Final

model.



Conclusion:

Hence we can conclude that using certain performance parameters in and applying

the necessary changes, we can simulate a car with better performance. These performances

are then analyzed in various different parameters like state of charge of battery,

acceleration, fuel economy etc.

We can also analyze the basic functions of UDDS and HWFET cycles and their role in

vehicle performance. More technological advances and our ability to read into the

performance data insures better cars in future.

Design and simulation of the vehicle is performed successfully.

Energy flow of the car is studied and analyzed.

Energy optimization is achieved in second model.



References:

[1] http://nptel.ac.in/courses/108103009/28 -web content for HEVs and EVs

[2] M. Ehsani, Modern Electric, Hybrid Electric and Fuel Cell Vehicles:

Fundamentals, Theory and Design , CRC Press, 2005

[3] http://en.openei.org/wiki/Autonomie_Automotive_Simulation_Tool

Figures:

[1] pretransmission parallel hybrid power train

[2] Sample of user interface of Autonomie http://energy.gov/eere/articles/models-

move-vehicle-design-forward

[3] model setup of the base model in Autonomie software.

[4] comparative table for the changes that were made in the base parameter.

THE END

http://nptel.ac.in/courses/108103009/28

http://en.openei.org/wiki/Autonomie_Automotive_Simulation_Tool

http://energy.gov/eere/articles/models-move-vehicle-design-forward

http://energy.gov/eere/articles/models-move-vehicle-design-forward