MEEM 5990Chief’s Challenge Fall 2009Team 3A• Vesna Avramoski• Brad Brodie• Ian Catrell• Jason Hutchinson• Erik Huyghe

• Erick Nickerson• Alfred Piggott• Mitch Waldrep• Greg Westrick

Overview – High Level Strategy

Organization Technical

Manpower

Roles

Goals

Targets

Project Strategy

Goals

Timing

Logistics

Strategy

Divide and Conquer

Sub Strategies

Controller Hardware

High Level Two Part Strategy, Organization and Technical

Project Overview

• Our hypothetical company (D Corp) has designed a hybrid vehicle

• The performance did not satisfy the Chief Engineer’s expectations.

• The goal handed down from the Chief Engineer is to maximize fuel economy and zero – 60 performance without exceeding the budget

• Zero - 60 and budget were determined subjectively through benchmarking

• The Fuel Economy Target was provided by the Chief Engineer

Targets• Fuel economy improvement ≥ 30% (≥ 22.6 mpg)

• Zero - 60 mph performance < 7.5 sec

• Improvement Budget = $1,900 (self-imposed)

Our key focus was to improve fuel economy first, then zero – 60 time, while staying within our budget.

Vehicle Targets - Benchmarking

Zero – 60 Target

5 % Below Best Benchmark

= 7.1 Sec (aggressive goal)

Benchmark Price $26,200

Budget = Benchmark Price – Chief’s Challenge Model Price

Price

$26,650

$26,900

$27,625

$26,200

$25,000

$25,500

$26,000

$26,500

$27,000

$27,500

$28,000

2010 Fusion 2010 Camry 2009 Altima 2009 Malibu

Zero-60 Time (sec)

8.7 8.47.1

11.0

7.6

0.0

2.0

4.0

6.0

8.0

10.0

12.0

2009 Malibu 2010 Fusion 2010 Camry 2009 Altima Target

Sec

Set Budget

Our self-imposed vehicle improvement budget was set at $1900.

Option Selection – Powertrain Components

E-Machine

Rear Differential

Battery

Electric Drive Ratio

Engine

• 4 Cyl, SI Engine, with DI & V.V.T

• Option 2• Cost: $100

• 2.48:1• Cost: $25

• NiMH• Option 1• Cost: $500

• 2.65:1• Cost: $25

• Base E-Machine, Higher RPM

• Option 0• Cost: $0• Lowest Mass

The bulk of the powertrain budget was spent on the NiMH battery.

Option Selection – Chassis Components

Tires

Body Material

Wheels

Aerodynamic

• Low Rolling Resistance• Improved Efficiency• Retained Spare Tire• No Loss of Customer

Satisfaction Points• Cost: $45

• Aluminum Body & Panels

• 50 Kg Mass Reduction• Cost: $775

• Active Front

• High Perceived Value

• Cost: $60

• Alloy• Lightweight, High Perceived-Value

• Cost: $30

The bulk of the chassis budget was spent on lightweight body material.

Control Strategy – Baseline Control Weakness(Baseline Control)

Actual Engine Operation Points During the Drive

Cycle

Idle

I.C.E Stop (Auto Off)

Wasted Fuel

The baseline control strategy allows the vehicle to idle frequently –outside of the high efficiency operating area for the ICE

Engine RPM During Drive Cycle

Engine Idling

Control Strategy – Target Propulsion Efficiency

Idle Torque=0, Opportunity Cost=1(worst)

Optimize the Engine Operating Points to Fall in this area.

ICE Off Torque=0, Opportunity Cost=0

ICE Efficiency E-Motor Efficiency

Goal Identify what areas need to improve to increase FE.

The E-Motor has a relatively high efficiency throughout the operating range, while the ICE does not.

Our primary goal was to improve ICE efficiency.

Desired ICE Operation – Ideal Target

Idle (Zero Efficiency for ICE)

When ICE on, optimize to get the maximum work out.

If ICE is not needed turn it off and keep off as long as possible to avoid startup penalties.

ICE Off (Zero Fuel Consumption)

We can improve FE by spending lots of money on high performance, low weight components, however it comes with a risk of poor sales.

Minimize IDLE (ICE on with zero fuel efficiency)

We chose to focus our controls on maximizing the efficiency of the ICE.

Can be controlled w/

software

Can be controlled w/

hardware choice

-50%-40%-30%-20%-10%

0%10%20%30%40%50%60%70%80%90%

100%

0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1Normalized Torque Output

Vehi

cle

Torq

ue R

equi

rem

en

Energy From EngineEnergy From Battery

Energy To BatteryTORQUE REQUEST STRATEGY

Regen Captured to Battery

Engine

Once maximum SOC is achieved, regeneration is stopped and engine request matches torque request.

ICE operates at constant efficiency, extra energy is used for regeneration.

Energy Lost to Heat

Energy To BatteryBRAKE BALANCE STRATEGY

-100%

-90%

-80%

-70%

-60%

-50%

-40%

-30%

-20%

-10%

0%

0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1Normalized Brake Torque Output

Brak

e To

rque

Req

uire

men

t

Regen Limit of Battery

Battery Regen Limit

Minimize Brake Torque used

Once maximum SOC is achieved, the entire brake torque request is sent to friction brake.

FrictionBraking

RegenBraking

Maximize regenerative braking, and use friction braking when necessary.

Battery Selection Summary

Parameter NiMH vs. Li-Ion △ (NiMH to Li-Ion)Total Mass 1671kg 1719kg + 48kg Total Cost $1735 $2585 + $850Total FE 50.74 58.38 - 7.64mpg

Annual Fuel Cost(12k mi/yr @ $2.50/gal)

$600 $517 $83/year(10.24 years until break even point)

Since the Li-Ion battery is much more expensive, and requires more than 10 years to offset that

expense, we chose the NiMH battery.

Results – Baseline vs. Optimized

Baseline Controls Optimized Controls

Baseline Chosen Options Chosen Options

UDDS FE (mpg) 17.4 30.3 50.8

Battery Energy Utilized (kW-h) 0.534 0.957 0.811

0 – 60 Time (s) 13.84 13.75 13.75

The theoretical minimum 0-60 time is 12.4 seconds. Our model

achieves 60 mph within 13.75 seconds – within 1.35 seconds of

the minimum.

Engine-off time was optimized to minimize the number of restarts.

TIME (Sec)

Engine Speed

Engine S

peed

Summary of Key Results

Description Value UnitsUDDS SOC Control: Starting SOC 80.0 (%) Ending SOC 45.0 (%) Change in SOC 35.0 (%)

Fuel Consumption: HWFET 7.18 L/100 km US06 9.82 L/100 kmFuel Economy: US06 23.95 mpg HWFET 32.78 mpgVehicle Speed Control Metric HWFET 1.0 NA US06 111.6 NASOC Change: HWFET 8.7 (%) US06 36.3 (%)

Additional Cycles

Team 3AResults Summary: Bonus Points

Description Value UnitsFuel Consumption: UDDS 4.64 L/100 kmFuel Economy: UDDS 50.7 mpgSpeed Control: Vehicle Speed Control Metric 1.0 NACost Scheduling Cost 0 $ I4 with DI and V.V.T Engine 100 $ Base E-Machine (50kW) 0 $ NiMH Battery 500 $ Rear Differential (2.65:1) 25 $ Electric Drive Ratio (2.48:1) 25 $ Low Rolling Resistance Tires 45 $ Alloy Wheels 30 $ Body Material Aluminum 775 $ High Efficiency Electrical System 175 $ Active Air Dam 60 $Total Cost 1735 $Acceleration 0 MPH to 60 MPH Acceleration* 13.75 secCustomer Satisfaction Customer Satisfaction Points 10 NA

Results Summary: Primary ScoringTeam 3A

Our development achieved 50.7mpg and a 13.75s 0-60mph time for $1735.