Erik van den Berg – Chief PowertrainDaan van der Wiel – Chief Engineer

Table of contents

The team

Top level concept

Powertrain

Electronics

Suspension

Chassis

Do’s and Don’ts

Founded in 2000

10 combustion cars

Known for lightweight concept

The team

The team

Large team of ±60 people

Full-time management

Part-time engineers

Old team members

Top Level Concept

First electric car

Young, inexperienced team

1 electrical engineering, 2nd year student

Set realistic targets!

Top Level Concept

Custom motors?

Torque vectoring?

4WD?

RWD car with torque vectoring possibilities

Top Level Concept

Power?

Pack capacity?

Target weight?

Simulations!

Top Level Concept

What defines our concept on a basic level?

Total power output of the motor(s)

Size of the battery pack (=Energy)

Weight of the car

Track Simulator:

Only straights simulated

Newton: F = m· a

Cornering performance based on competition experience

Track Simulator in Matlab/Simulink

Top Level Concept

Competition Simulator: Simulations of whole competition in Matlab/Simulink

Dynamic events only

All kinds of cars simulated, lightweight low power to heavy

high powered cars

Sensitivity analysis performed for uncertain parameters

DUT11

DUT11DUT11

DUT11

Conclusion from simulations:

Power: 40-50 kW

Accumulator capacity: 6.0 kWh

Resulting car weight about 180 kg

Packaging

Determine layout and design spaces

Large effect on final balance and handling

Trade-off between CoG location and yaw inertia

Dependent on choice of motors

Powertrain

Powertrain: System Description

The Accumulator

Overview Accumulator:

5.7 kWh for 100% DOD

355V nominal, 400V peak

288 LiPo cells, wired in 96S3P

43 kg

Exchangeable in 10 minutes

Rechargeable to 90% in 1 hour

Elithion BMS

Sizing of the Accumulator:

Needed energy content derived from Motec data

5,7 kWh enough for Endurance at 100% power in theory

The Cells:

Radio Control grade Lithium Polymer cells

Suitable ratio of power density vs energy density

Power Density: 4.3 kW/kg

Energy Density: 176 Wh/kg

The Modules:

Ensuring safety: module voltage 29.6V

Serviceable: pack can be assembled in 45 min.

Transparent polycarbonate for inspection and protection

The Motors:

• Ideal motor power derived from simulation

• AMK Antriebe motors used with 56 kW combined

• Industrial material: simple & reliable

The Motors & Motor Controllers:

Motor Type: AMK DT5-30 (PM synchronous)

Power: 14 kW nominal/ 28 kW peak

RPM: 10,500 max

Weight: 12 kg (per motor)

MC Type: AMK KW-40 Motor Controllers

Input voltage: 350 VDC

Cooling type: Water cooling (motors & MC’s)

The Motors: Power curves

45 km/h 120 km/h

The Transmission

Overview:

• Ratio of 1:7.2

• Very slim design needed

• Single step

• Spur gears

• Oil bath lubrication

ECU

HV Battery management

system

Steering wheel

DashboardSensors Switches

IMD

MC’s AIR’s

LV Battery

CAN-Bus

Analogue & Digital

Power

Analogue & Digital

Control System Overview:

Electronic Control Unit In house developed

Lightweight (450 gr.)

Relatively cheap

Safety functionality

• Dashboard with LCD display for information• Warnings• Lap times• Energy Consumption

• Buttons on the steering wheel• Motor torque• Motor braking• Menu controls• Power boost

Dashboard & Steering Wheel

Suspension

Load path analysis

Chassis

Monocoque

Carbon fibre monocoque

Vacuum infusion

Motor cover

Length/Width/Height 2628/1407/1064 mm

Weight 175 kg

Weight distribution 41/59

Power (nom./peak) 28/55 kW

Tractive system voltage 400 V

Battery pack capacity 5.7 kWh

Do

Recruit electrical engineering students when designing an

electric car!

Make clear agreements with suppliers

Use big safety margin on delivery time

Perform quality control (checklists)

Do

Use test time efficiently (good test plan, clear tasks, rested,

exchangeable battery pack)

Train your drivers

Practice entire endurance before competition

Execute important tests before the competition

Don’t

Execute the rain test the night before you leave to FSUK…

Expect something is simple to design (design everything!)

Neglect high voltage safety (≥2 people, clear signs,

responsible person, gear)

Underestimate the battery pack

Looking back...

Goals and expectations were chosen such that they were a

challenge to meet but feasible with the resources we had.

The car was designed to score the most points overall, not

on individual events. The concept and parameters chosen

at the start of the year gave us exactly that!

Questions?

Length/Width/Height 2628/1407/1064 mm

Weight 175 kg

Weight distribution 41/59

Power (nom./peak) 28/55 kW

Tractive system voltage 400 V

Battery pack capacity 5.7 kWh

Steer by wire

Powertrain Weight Distribution

43

24

8.5

9

2.54.5 3.5

Weight per Part of Powertrain [kg]

AccumulatorMotorsMotor ControllersGearboxesHalfshaftsCoolingHV Wiring

Regenerative braking recovers 20% of used energy (1.2 kWh)

Actual Power Usage during Endurance:

Controller

Radiator

Pressure valve

Catch can

Pump

Gearbox

Motor

Accumulator Tips & Tricks

Always a lot more work than you anticipate

When working with HV always have two people present!

Modular construction makes assembly easier and safer

Ensure you have plenty of fuses

The Cooling System: Schematic Overview

The Cooling System: Testing

Spindles

Al 7075-T6

Integrated tripod-housing

Integrated brake disk carrier

Rims

CFRP – Aluminium hybrid

Relatively easy to produce

No special tools required