Fundamentals of Vehicle Design

Dr. Shirish P Patil &

Dr. Kamarul Tawi

Course Objectives

• Understand vehicle manufacturing organization• Understand vehicle development process• Understand vehicle systems and attributes (properties)

• Learn to set performance specifications for a new vehicle

• Understand system/component contribution towards vehicle performance

• Learn to set specifications for system/component design• Learn to design components to meet specifications

Course Outline1. Overview of vehicle design process

2. Vehicle performance specifications

3. Vehicle acceleration & powertrain design specification

4. Vehicle deceleration & brake design specification

5. Vehicle ride & chassis design specification

6. Vehicle roll-over & chassis design specification

7. Vehicle handling & chassis design specification

8. Vehicle durability & chassis design specification

9. Vehicle crash safety & body design specification

10. Design of the suspension system

11. Design of the steering system

12. Design of the body/door system

Course Schedule

• Every Tuesday: classroom instruction (2 hours)• Every Thursday: group project discussion (3 hours)• Study time: approximately 4 hours/week

Evaluation Criteria

• Final written project report including weekly log of activities (40%)

• Final project presentation (15%)

• Mid-term project presentation (5%)

• Team participation & contribution (40%)

   

No.Performance

CriteriaLevel 1 Level 2 Level 3 Level 4 Level 5

1. Contributions Does not provide ideas when participating in the group discussion.

Rarely provides ideas when participating in the group discussion.

Sometimes provides ideas when participating in the group discussion. A satisfactory group member who does what is required.

Usually provides useful ideas when participating in the group discussion. A strong group member who tries hard.

Routinely provides useful ideas when participating in the group discussion. A leader who contributes a lot of effort.

2. Effort in Problem-solving

Does not try to solve problems or help others solve problems. Lets others do the work.

Rarely tries to solve problems or help others solve problems.

Does not suggest or refine solutions, but is wiling to try out solutions suggested by others.

Refines solutions suggested by others

Actively looks for and suggests solutions to problems.

 

3. Attitude Always publicly critical of the project or the work of other members of the group. Has negative attitude about the task(s).

Is often publicly critical of the project or the work of other members of the group. Is often negative about the task(s).

Is occasionally publicly critical of the project or the work of other members of the group. Usually has a positive attitude about the task(s).

Is rarely publicly critical of the project or the work of others. Often has a positive attitude about the task(s).

Is never publicly critical of the project or the work of others. Always has a positive attitude about the task(s)

4. Participation and Working with Others

Does not participate, listen to, shares with, and supports the efforts of others. Is not a good team player.

Rarely participate, listens to, shares with, and supports the efforts of others. Often is not a good team player.

Often participate, listens to, shares with, and supports the efforts of others, but sometimes is not a good team member.

Usually participate, listens to, shares, with, and supports the efforts of others. Does not cause ”ripples” in the group.

Almost always participate, listens to, shares with, and supports the efforts of others. Tries to keep people working well together.

Team Participation & Contribution Evaluation

Project Description

• Each team (5 students) will choose a passenger vehicle to be engineered

• Team will decide the performance specifications for the vehicle

• Team will design the specifications for the powertrain/brake/suspension/body system so that vehicle specifications are satisfied

Requirements for the Report

• List of specifications for cost, weight, acceleration, braking, ride, handling, roll-over, crash safety and durability. Method of setting each specification

• Design of powertrain system properties to meet acceleration specification

• Design of brake system properties to meet braking specification

• Design of suspension & steering system properties to meet ride, handling, roll-over and durability specification

• Design of body system properties to meet crash-safety specification

• Design of door system properties to meet door closing effort specification

Vehicle ClassificationVehicle Type

Body Style Power Train Suspension

Passenger Car 2D/3D/4D/5D UniBody Engine: 1.0-3.0LTrans: 5spd/AutoDriveline: FWD

Front: McPhersonRear: Multi-link

MPV 4D/5D UniBody Engine: > 2.0LTrans: AutoDriveline: FWD

Front: McPhersonRear: Multi-link

SUV 5D Unibody or Body on Frame

Engine: 1.8-5.0 LTrans: AutoDriveline: FWD/RWD/AWD

Front: McPherson/SLARear: Multi-link/Solid Axle

Luxury Car 4D Unibody or Body on Frame

Engine: >2.5 LTrans: AutoDriveline: FWD/RWD

Front: SLARear: Multi-link

Sports Car 2D/3D Unibody Engine: >3.5 LTrans: 5SpdDriveline: RWD

Front: McPhersonRear: Multi-link

Pickup Truck 2D/4D Body on Frame Engine: >2.5 LTrans: AutoDriveline: RWD/AWD

Front: SLARear: Solid Axle

Commercial Truck

2D Body on Frame Engine: >5 LTrans: AutoDriveline: RWD

Front: SLARear: Solid Axle

How to prepare vehicle specifications?

• Understand what your customer desires

• Understand what your competition offers

• Understand government regulation

Team Exercise

• Pick a vehicle you plan to design

• Write vehicle specifications by studying 2 or more competition vehicles (study dealer specs., do internet search, etc.)

Cost Specification

• What is the intended selling price of the car?

• How many units do you plan to sell?

• Will you make any profit?

Weight Specification

• What is intended gross vehicle weight (GVW)?

• How many passengers?

• What is the luggage capacity?

• Weight distribution?

Geometry Specification

• Wheelbase?

• Tread?

• Ground clearance?

• Tire size?

Acceleration Specification

• 0 to 100 km/h in how many seconds?

• Engine torque/power?

• Transmission speed? Auto or Manual?

Braking Specification

• Deceleration level required?

• Stopping distance from 100 km/h?

• Dry surface/Wet surface?

Ride Specification

• Desired ride frequency?

• Desired passenger acceleration on an average road surface?

Roll-over Safety Specification

• What is the max lateral acceleration the vehicle will sustain?

Handling Specification

• Minimum turning radius?

• Understeer or oversteer?

• Steer gradient?

Durability Specification

• What is the desired life of a suspension component?

Crash Safety Specification

• What is the average deceleration experienced during frontal crash?

Organization of an Automaker

LeadershipVehicleEngineering

Sales&

Marketing

Manufacturing&

Assembly

FinanceAfterSalesService

DealerNetwork

Suppliers

Concept to Customer Process

CustomerRequirements

Regulations

VehicleProgram

VehicleEngineering

Manufacturing&

Assembly

Sales

Service

Organizational Responsibility

Organization Responsibility Examples

Central Leadership

Run the company profitablyProvide leadership for the future

Provide initiatives to buildEco-friendly cars

Finance Raise & provide funds to run operations

Provide loans to customers for purchasing vehicles

Vehicle Engineering

Engineer the vehicle to meet customer specifications and regulatory requirements

Design & test parts and vehicles to meet specs.

Manufacturing & Assembly

Manufacture parts & assemble vehicles

Manufacture stamped body panels & engine castings

Sales & Marketing Gather customer specifications Set customer wants

After Sales Service

Provide after sales customer service

Ensure availability of replacement parts

Dealer Network Sell & service cars

Suppliers Manufacture parts & assemble systems

Design/test/manufacture parts

Vehicle Development Organization

Vehicle DevelopmentOrganization

ProductEngineering

VehicleEngineering Styling

Body EngineeringChassis Engineering

Powertrain EngineeringClimate Control Engineering

Electrical Engineering

Package EngineeringWeight EngineeringSafety EngineeringVehicle DynamicsVehicle Durability

Vehicle NVHVehicle Thermal&Aero

Prototype Planning/Test

Exterior StylingInterior Styling

Product Engineering

Organization Responsibility

Body Engineering Develop exterior sheet metal and interior trim to meet engineering and cost specifications

Chassis Engineering Develop suspension/steering/brake/frame system components to meet engineering and cost specifications

Powertrain Engineering Develop engine/transmission/driveline/fuel/exhaust system components to meet engineering and cost specifications

Climate Control Engineering

Develop HVAC system components to meet engineering and cost specifications

Electrical & Electronic Engineering

Develop electrical/electronics/entertainment system components to meet engineering and cost specifications

Vehicle Engineering

Organization ResponsibilityPackage Engineering Ensure all systems and components fit in the vehicle

Weight Engineering Ensure all systems and components meet weight spec.

Safety Engineering Ensure that the vehicle meet the regulatory safety spec.

Vehicle Dynamics Ensure that the vehicle meet the regulatory/customer ride & handling spec.

Durability Engineering Ensure that the vehicle meet the customer durability spec

Vehicle NVH Ensure that the vehicle meet the customer Noise, Vibration & Harshness spec.

Prototype Planning/Test Plan & manage prototype builds and testing

Styling

Organization Responsibility

Exterior Styling Develop exterior sheet metal Class I (Styled) clay surface

Interior Styling Develop interior trim Class I (Styled) clay surface

Vehicle Development Process

Vehicle,System &

ComponentSpec

ProductionDesign & Testing

PrototypeDesign &Testing

ProgramApproval

ConceptEvaluation

ToMeet Spec

Fix ProblemsBefore

Production

Vehicle Development Process

Process Outcome Activities Examples

Prepare Spec. Final vehicle, system & component spec.

• Hold customer clinics• Benchmark vehicles• Study regulations

• 0 to 100 kmph in 9 sec• Investment cost < $ 500M• no structural failure < 150,000 km

Concept Evaluation

Data required to make decisions

• Design feasibility studies• Cost feasibility studies

• Is acceleration spec. possible?• Is investment target possible?

Program Approval

GO or NO GO decision

• Program meeting

Prototype Design & Testing

Data required for 80% confidence in the design

• Part design• Manufacturing & Assembly• Testing

• CAD surface or solid with drawings• soft tooled part & pilot plant assembly• CAE/Lab/Proving Ground testing

Production Design & Testing

Data required for 99% confidence in the design

• Part design• Manufacturing & Assembly• Testing

• CAD surface or solid with drawings• hard tooled part & plant assembly• CAE/Lab/Proving Ground testing

Fix Problems before Launch

100% confidence • Final fixes by launch team

Vehicle Systems & Attributes

Vehicle

Systems Attributes

• Body• Chassis

• Powertrain• Climate Control

• Electrical

• Cost• Weight • Package• Safety

• Dynamics• Durability

• NVH•Styling

Function of Vehicle Systems

Vehicle System Function

Body • Provide durable attachment for other major systems• Provide safe and pleasant seating environment for all passengers• Protect passengers from crashes

Chassis • Provide capability to steer the vehicle• Provide capability to brake the vehicle safely• Provide isolation between road and passengers

Powertrain • Provide capability to accelerate the vehicle by transferring torque to wheels• Provide capability to control vehicle speed• Meet regulatory exhaust requirement

Climate Control • Maintain comfortable temperature distribution for passengers• Provide windshield defrost capability

Electrical & Electronics • Provide power supply where needed• Provide desirable entertainment system• Provide functional censors and controls

Vehicle Attributes

Vehicle Attributes Description

Cost Lowest production, assembly and distribution cost compared to competitive vehicles

Weight Lowest curb weight compared to competitive vehicles in its weight class

Package Best use of the space to provide comfort and amenities to passengers

Safety 5* crash rating from the Federal Motor Vehicle Safety Standard (FMVSS)

Dynamics Best ride & handling performance compared to competitive vehicles

Durability Highest reliability and high mileage durability compared to competitive vehicles

NVH Lowest noise, vibration and harshness compared to competitive vehicles