Automotive Systems course (Module 08) - Starting Systems for road vehicles

29 de novembro de 2016 | 1

Sistemas A

uto

mó

veis

Starting Systems

Mário Alves ([email protected])

mailto:[email protected]


Sistemas A

uto

mó

veis

Outline

• Starting system: definition, components, requirements

• Starter motor: definition and classification

• Starter motor: excitation and electrical connections

• Starter motor types

• direct drive, axial (with lever)

• gear reduction, co-axial (without lever)

• gear reduction, co-axial (with lever)

• gear reduction (epicyclical, axial, with lever)

• permanent magnets, planetary gear reduction

• Direct drive vs. gear reduction

• Stator, rotor, brushes, overrunning clutch

• Heavy vehicles starter motors

• Start-stop systems

• Belt/Flywheel Alternator Starter

• Glossary

• Recommended references


Sistemas A

uto

mó

veis

Starting System: definition and main components

• Starting system

• enables to crank the internal combustion engine

• Main (typical) components

• (battery, ignition key, flywheel)

• starter (aka cranking) motor

• starter solenoid

• electric motor

• overrunning clutch (aka bendix)

• pinion (small gear wheel)

• electric cabling

• command circuit (controls starter relay/solenoid)

• power circuit (feeds electric motor)

http://www.procarcare.com/images/shar/encyclopedia/8852BG58.gif




Sistemas A

uto

mó

veis

Starting System: main components

http://www.pearltrees.com/kitching/item125272003

• It may also include

• starter fuse

• protects against over-currents in the control circuit (thin red wire)

• power circuit (thick red wire) is unfused

• starter relay

• to connect to the starter solenoid

• reduces control current at the IG switch

• neutral or clutch safety switch

• automatic transmission

• signals Neutral or Park position

• manual transmission

• signals Clutch actuation




Sistemas A

uto

mó

veis

Starting System: starter motor outlook





Sistemas A

uto

mó

veis

Starting System: requirements

• Main requirements • support high currents

• battery, wiring, connectors, relays, switches, brushes, commutator, stator/rotor windings

• starting current draw of typically 100-200 A (few seconds)

• peak (transient) currents of typically >500 A (few hundred ms)

• note: control circuit (solenoid) current of typically several A

• adequate power/torque, to support

• engine + other loads (water and oil pumps, A/C, alternator)

• friction, ICE compression, oil viscosity, inertia

• high durability/reliability

• user-perspective: no need to replace the starter motor for the vehicle’s lifetime

• typically 15-20 years & 150-300 thousand km lifetime

• start-stop systems impose much higher standards

• compact size, light-weight, silent, low-cost

…


Sistemas A

uto

mó

veis


• Starting current waveform

• Toyota 1600 CC 4A-FE gasoline engine

• Peak current 500 A | Steady state current (2) = 116 A

Waveform obtained using Fluke123 Scopemeter + active current probe + FlukeView @ ISEP Automotive Lab


Sistemas A

uto

mó

veis


• Starting current waveform

• Toyota 2000 CC 2C Diesel engine

• Peak current (1) = 848 A | Final current (2) = 112 A

Waveform obtained using Fluke123 Scopemeter + active current probe + FlukeView @ ISEP Automotive Lab


Sistemas A

uto

mó

veis

Starter motor: definition and classification

• Definition

• a starter (AKA starter motor) is a motor used for rotating an ICE so

as to initiate its operation under its own power

• The starter can be

• an electric motor

• a pneumatic motor

• a hydraulic motor

• an ICE (in case of very large engines)

• Most road vehicles feature electric motor starters

• thus, we will address this type of starter

… https://en.wikipedia.org/wiki/Starter_(engine)

https://en.wikipedia.org/wiki/Starter_(engine)

https://en.wikipedia.org/wiki/Starter_(engine)


Sistemas A

uto

mó

veis

Starter motor: classification

• Electric starter motors can be classified according to, e.g.: • excitation (stator) and electrical connections (stator-rotor)

• permanent-magnets

• electromagnets

• shunt-wound | series-wound | compound-wound

• gear ratio

• direct drive (1:1 gear ratio)

• gear reduction (N:1 gear ratio, N > 1)

• parallel gear train | planetary (epicyclical) gear train

• mechanical layout

• axial (pinion gear aligned with motor shaft)

• co-axial (pinion gear aligned with starter solenoid)

• mechanical drive (of the flywheel)

• pre-engaged (pinion gear engages flywheel gear before spinning)

• inertia-drive (pinion gear spins before engaging flywheel gear)

…


Sistemas A

uto

mó

veis

Starter motor: excitation and electrical connections

A. Shunt-wound

B. Series-wound

C. Compound-wound

D. Permanent-magnet

http://what-when-how.com/automobile/starter-motors-and-circuits-automobile/
















Sistemas A

uto

mó

veis


http://www.sw-em.com/starter.htm

Series-wound motor Permanent-magnet motor






Sistemas A

uto

mó

veis


… http://www.sw-em.com/starter.htm

• Electrical wiring schematics (series-wound)

• Control circuit (solenoid) and power circuit (stator + rotor)






Sistemas A

uto

mó

veis


… http://what-when-how.com/automobile/starter-motors-and-circuits-automobile/

• Electrical circuits

A. inertia-drive starter

B. pre-engaged starter
















Sistemas A

uto

mó

veis

Starter motor: direct drive (1:1), axial (with lever)

http://www.rollaclub.com/wiki/index.php?title=Tech:Electrical/Starter_Motor/Conventional_Type&redirect=no




Sistemas A

uto

mó

veis



1. IG ON STA

pinion engages ring




Sistemas A

uto

mó

veis



2. Pinion & Ring

fully engaged

motor rotates &

cranks ICE




Sistemas A

uto

mó

veis



3. IG STAON

pinion disengages

from ring




Sistemas A

uto

mó

veis

Starter motor: gear reduction, co-axial

http://www.rollaclub.com/wiki/index.php?title=Tech:Electrical/Starter_Motor/Reduction_Type




Sistemas A

uto

mó

veis



• IG STA




Sistemas A

uto

mó

veis



• Pinion engaged




Sistemas A

uto

mó

veis



• IG STA ON




Sistemas A

uto

mó

veis

Starter motor: gear reduction, co-axial (with lever)

http://autosystempro.com/cranking-motor-designs/








Sistemas A

uto

mó

veis

Starter motor: gear reduction (epicyclical, axial, with lever)

http://www.rollaclub.com/wiki/index.php?title=Tech:Electrical/Starter_Motor/Planetary_Type




Sistemas A

uto

mó

veis

Starter motor: permanent magnets, planetary gear reduction

http://www.import-car.com/diagnostic-solutions-starter-battery-diagnostics/

http://what-when-how.com/automobile/permanent-magnet-starter-motor-automobile/




























Sistemas A

uto

mó

veis

Starter motor: direct drive vs. gear reduction

http://www.elreg.com/blog/why-are-gear-reduction-starters-replacing-direct-drive-starters

• Electrical power/current draw • direct drive starters require more electrical power/current

• impacts battery, cables and other components

• Weight • gear reduction starters are smaller and lighter

• Maintenance • gear reduction starters have a higher part count

• Cost • direct drive starters are slightly cheaper

• Speed • typically, gear reduction starters turn the flywheel slower

• however, their torque is higher, so perform better when pistons are at TDC on the compression stroke where it is most needed; this is why they are ideal for diesel/high-compression ICEs




















Sistemas A

uto

mó

veis

Starter motor: stator and rotor interleave

http://autosystempro.com/tag/starting-system/

• Electric current in the rotor windings must flow in a

direction such that additive torque is obtained

…






Sistemas A

uto

mó

veis

Starter motor: rotor


• Laminated core


http://www.groschopp.com/how-to-check-a-motor-armature/




















Sistemas A

uto

mó

veis

Starter motor: rotor


…

Lap winding Wave-wound winding






Sistemas A

uto

mó

veis

Starter motor: stator



Permanent-magnet

stator

Electromagnets stator








Sistemas A

uto

mó

veis

Starter motor: brushes

http://www.howacarworks.com/ignition-system/checking-and-replacing-starter-motor-brushes

• Usually 2 or 4 brushes



















Sistemas A

uto

mó

veis

Starter motor: overrunning clutch

http://autosystempro.com/starter-drives/

• Motivation

• ratio of the number of teeth on the flywheel ring gear and

the starter pinion gear is usually between 15:1 and 20:1

• starter motor rotates 15 to 20 times faster than ICE

• normal ICE cranking speed is about 100-200 RPM

• for a gear ratio of 20:1, the starter motor rotates at

2000-4000 RPM

• if the ICE started and was accelerated to 2000 RPM, the

starter would speed up to 40000 RPM!

• this would destroy the starter motor

if it was not disengaged from the ICE

…






Sistemas A

uto

mó

veis



• It is a roller-type clutch that transmits torque in one direction

only and freewheels in the other direction

• it allows the starter motor to transmit torque to the ring gear but

prevents the ring gear from transferring torque to the starter motor.

…






Sistemas A

uto

mó

veis


http://www.tractordata.com/articles/technical/overrunning-pto-clutch.html

• Dynamics

• Note: starter pinion keeps rotating with the flywheel, after cranking

…

During cranking:

pinion drives flywheel After cranking:

flywheel does NOT drive pinion








Sistemas A

uto

mó

veis

Heavy Vehicles Starter Motors

http://what-when-how.com/automobile/inertia-drive-starter-motor-automobile/

• Large ICEs require more cranking power/torque

• trucks, tanks, big stationary diesel engines

• Increased cranking power/torque can be achieved through

• gear reduction (also common in light vehicles)

• higher voltage (24 V, 42 V)

• inertia-drive

• sliding armature















Sistemas A

uto

mó

veis

Heavy Vehicles Starter Motors: inertia-drive


• Operating principle

• pinion is not fixed rigidly to the motor shaft - it is threaded on to it

• when the shaft starts spinning, the inertia of the pinion causes it to lag

behind and thus move along the shaft into engagement with the ring-

gear on the fly-wheel

• once the engine starts, it spins the pinion faster than the starter motor

shaft, screwing the pinion back down its thread and disengaging it

Ring gear

(flywheel)

Cushion

spring

Helical splines

(quick thread

Cushion

spring















Sistemas A

uto

mó

veis


http://www.uniquecarsandparts.com.au/auto_technical_terms_9.php

• Detailed view

• pinion, sleeve and thread

http://www.jcrsupplies.co.uk/products/STARTER_MOTOR_REPAIR_PARTS/STARTER_MOTOR_DRIVES__PINIONS_AND_GEARS/M35J_and_M35G_INERTIA_STARTER_MOTOR_PINION_DRIVE_10_TEETH_.html








Sistemas A

uto

mó

veis


https://en.wikipedia.org/wiki/Starter_(engine)#Inertia_starter

• Advantage

• since an inertia-drive starter is not driving the engine directly, it can

be of lower power than a “standard” pre-engaged starter

• this allows a lower weight and smaller size starter, as well as

lighter electrical cables and smaller batteries to power it

• thus, it most adequate for large ICEs

• e.g. aircrafts with large radial piston engines




Sistemas A

uto

mó

veis



• Disadvantages

• increased cranking time – can take a few seconds

• upon ICE cranking, the pinion returns back so violently that there has

to be a strong spring on the shaft to cushion its impact

• the violent engagement and disengagement of an inertia starter can

cause heavy wear on the gear teeth;

• to overcome these problems, the pre-engaged starter was

introduced (in the 80s)

• a starter solenoid is used

• pinion gear engages flywheel gear before starting to spin

http://www.howacarworks.com/basics/how-the-starting-system-works














Sistemas A

uto

mó

veis

Heavy Vehicles Starter Motors: sliding-armature

http://what-when-how.com/automobile/heavy-vehicle-starter-motors-automobile/

• Operating principle

• Starter motor armature (rotor) progressively slides along the axis

• several armature windings (gradually feed)

• full torque is achieved when all armature windings are energized,

• but this happens only when the pinion gear is fully engaged with flywheel gear

• This enables

• smoother pinion-flywheel engagement

• less cranking noise

• less gear deterioration

• lower peak currents at start

• thinner electrical wires

• smaller battery

…















Sistemas A

uto

mó

veis



• Operation

• the motor is shown in the rest position

• when the field windings (stator) are energized

• the armature is pulled to the left and

• the pinion gear engages with the

ring gear (flywheel)

PINION















Sistemas A

uto

mó

veis



• Three separate field (stator) windings

• main winding

• thick-section (low-resistance) winding

• connected in series to the armature

• auxiliary winding

• thinner wire (high resistance

• connected in series with the armature

and in parallel with the main winding

• holding winding

• high-resistance winding

• connected in parallel with the armature

as well as with the other two windings















Sistemas A

uto

mó

veis



• A two-stage solenoid switch, mounted on the starter operates the

starter, and is energized by the IG switch

• when the ignition switch is operated, the first pair of contacts closes

but the second pair is held open by a pawl that engages in a slot in the

trip lever – Figure A

• Once the pinion is near fully engaged with the ring gear, the pawl

allows the second pair of contacts to close – Figure B

PINION















Sistemas A

uto

mó

veis



• A: auxiliary windings, holding windings and armature are energized;

armature rotates slowly and moves axially towards the field poles;

simultaneously, the pinion slowly engages with the ring gear

• B: upon full engagement, the release disc on the armature strikes the

pawl and the trip lever closes the second pair of contacts; now current

feeds the main windings, causing the motor to develop its full torque















Sistemas A

uto

mó

veis

Start-stop systems

• Motivation

• estimated fuel consumption of an idling engine is 0.6 l/hour per

liter of engine displacement

• an idling 2.0 liter engine consumes more than 1 liter of fuel

per hour

• engine idle for 30 minutes a day results in one fuel tank

every four months, without moving!

• engine idle for more than a few seconds consumes more fuel and

generates more greenhouse gas emissions than turning it off and

starting it up again

• thus, ICE should be turned off (automatically) at idle

• as far as both ICE and catalyst have achieved normal

operating temperatures (warmup phase finished)

http://www.ecomobile.gouv.qc.ca/en/ecomobilite/tips/idling_engine.php

http://www.roadandtrack.com/new-cars/car-technology/news/a18043/startstop-making-the-most-of-just-hanging-around/
























Sistemas A

uto

mó

veis

Start-stop systems

• Motivation

• fuel savings and emission reductions of 8-15 % (measurements

based in the New European Driving Cycle (NEDC))

• In combination with a modern gasoline engine, the amount of

fuel required for warm starting is only the same as that used

when idling for 0.7 seconds.

• stop function has a beneficial effect from the very first

second (for both people and environment).

http://de.bosch-

automotive.com/en/parts_and_accessories/motor_and_sytems/start_stop_system/functionality_start_stop_system/functionality_start_stop_system

http://de.bosch-automotive.com/en/parts_and_accessories/motor_and_sytems/start_stop_system/functionality_start_stop_system/functionality_start_stop_system







Sistemas A

uto

mó

veis

Start-stop systems

• Configurations

• for “conventional” ICE powertrains

• “conventional” battery, starter and alternator

• Belt Alternator Starter (BAS) aka Integrated Starter

Generator (ISG)

• for hybrid electric-ICE powertrains

• hybrid powertrain cranks the ICE

• In this module, we will address start-stop systems for

conventional ICEs

• (hybrid powertrains will be treated separately)

http://de.bosch-

automotive.com/en/parts_and_accessories/motor_and_sytems/start_stop_system/functionality_start_stop_system/functionality_start_stop_system








Sistemas A

uto

mó

veis

Start-stop systems: market trend

http://www.altenergystocks.com/archives/energy_storage/batteries/




Sistemas A

uto

mó

veis






Sistemas A

uto

mó

veis


http://www.marketsandmarkets.com/Market-Reports/variable-valve-timing-vvt-market-1206.html
















Sistemas A

uto

mó

veis

Belt/Flywheel Alternator-Starter (BAS and FAS)

• Both BAS and FAS systems

• substitute conventional starters/alternators

• starter (motor) mode: BAS/FAS drives crankshaft

• generator (alternator) mode: crankshaft drives BAS/FAS

• enable “mild-hybrid” (AKA “micro-hybrid”) operation

• mild levels of regenerative braking, start-stop, power assist

• trend for higher voltage systems/batteries (> 36 V)

• Belt Alternator-Starter (BAS)

• belt connects BAS and ICE crankshaft pulley

• Flywheel Alternator-Starter (FAS)

• mounted directly to the engine crankshaft

(replaces existing flywheel)

http://wikicars.org/en/Belt_Alternator_Starter_(BAS)




Sistemas A

uto

mó

veis


• Typical block diagram

http://www.eetimes.com/document.asp?doc_id=1272189




Sistemas A

uto

mó

veis


• Power MOSFET control diagram

• brushless DC motors tend to be preferred over induction motors on

account of their efficiency and controllability





Sistemas A

uto

mó

veis

Belt Alternator-Starter (BAS)

• GM BAS “mild-hybrid”

• 115V lithium-ion battery

• 15 kW alternator

• regenerative braking

(helped by alternator torque load)

• up to 11 kW (15 hp) of electric power

assistance during acceleration

• automatic ICE start-stop

http://gmauthority.com/blog/gm/gm-engines/luk/

http://www.gminsidenews.com/forums/f12/next-generation-gm-hybrid-system-announced-geneva-61607/index6.html






















Sistemas A

uto

mó

veis

Flywheel Alternator-Starter (FAS)

• Volvo Crankshaft-Integrated Starter Generator (C-ISG)

• pioneered by Volvo in 2001

• 42V system intended for a “mild hybrid” application

• current C-ISG

• XC90 T8 PHEV model

• 400 hp Direct-Injection Turbo&Supercharged

• 2.0 liters, 4 cylinders, in-line configuration

• 65 kW (87 hp) electric rear axle drive (ERAD)

• C-ISG

• 9.2 kWh lithium-ion battery

• 34 kW (46 hp) generator/motor (150 N.m torque)

• water-cooled

• 3 functions:

• starter, generator

• power boost

• torque infill between gear shifts (smooth drive feeling)

• extra boost (start-up and hard acceleration

http://insideevs.com/volvo-xc90-t8-phev-first-drive-recap/

https://www.media.volvocars.com/global/en-gb/media/pressreleases/5278




















Sistemas A

uto

mó

veis

Flywheel Alternator-Starter (FAS)

• Honda ACG

• brushless DC motor/generator

• Starter: current applied to the stator coils

• Alternator: rotor magnets produce EMF

http://world.honda.com/motorcycle-technology/Engineidlingstop/p3.html

Starter operation

Alternator operation

http://www.hondacengkareng.com/teknologi-acg-starter-motor-honda/
















Sistemas A

uto

mó

veis

Glossary (English/Portuguese)

• …


Sistemas A

uto

mó

veis

Recommended references

• http://www.autoshop101.com/forms/elec04.pdf

• https://www.youtube.com/watch?v=ITFW2PkqXWw

• http://www.roadandtrack.com/new-cars/car-technology/news/a18043/startstop-making-

the-most-of-just-hanging-around/


























Engineering

Automotive Systems course (Module 08) - Starting Systems for road vehicles