Mazda s Approach for Developing Engines from a … · Mazda’s Approach for Developing Engines...

Mazda’s Approach for Developing Engines from a Perspective of Environmental Improvement

Mazda’s Approach for Developing Engines from a Perspective of Environmental Improvement

2015 ERC Symposium

Mitsuo HitomiMazda Motor Corporation

• Improving thermal efficiency of ICEs

• Goal of SKYACTIV engines

• SKYACTIV engines: 1st step

• SKYACTIV engines: Next step

• Investigation results of boosted downsizing enginesand future strategy for engine displacement

Contents

3

Energy losses of ICE

Improving thermal efficiency of ICEs

Fuel Economy Improvement＝Loss reductionAll technologies for improving fuel economy must overcome these seven controlling factors.

Effective work

Exhaust loss

Hea

t Ene

rgy

Bal

ance

(%)

Heat Energy Balance vs. Load

0

20

60

80

100

20 40 60 80 100Load (%)

40

Radiation, Misfiring loss

Cooling loss

Control factors

Pressure difference

between In. & Ex.

Mechanical friction

Specific heat ratio

Heat transferto wallPumping loss

Mech. friction loss

Combustionperiod

Combustion timing

Compression ratio

Gasoline engine Diesel engine

Further reduction

LeanＨＣＣＩ

Adiabatic

Higher CR

LeanＨＣＣＩ

Roadmap to the goal of ICE Distance to idealFar Close

Specificheat ratio

Heat transferto wall

Compression ratio

Combustion period

Control factors

Combustiontiming

Pressure diff.Btw IN. & Ex.

Mechanicalfriction

Gasoline engine and diesel engine will look similar in the future.

Adiabatic

Further reduction

Friction reduction

More homogeneous

World lowest CR

TDC combustion

TDC combustion

World highest CR

Friction reduction

Miller cycle 1stst

ep S

KYA

CTI

V-G

1stst

ep S

KYA

CTI

V-D

2ndst

ep S

KYA

CTI

V-G

2ndst

ep S

KYA

CTI

V-D

3rd

step

=Goa

l

Current Current

Better mixing

4

Improving thermal efficiency of ICEs






Contents

After 2011 big earthquake in Japan

0.97

0.80

0.520.470.450.430.39

0.170.09

(kg-CO2/kWh)1.2

1.0

0.8

0.6

0.4

0.2

0France Canada Japan Italy UK Germany USA China India

0.52

Specific CO2 emission from electric power generation is assumed to be 0.5kg-CO2/kWh.

Specific CO2 emissions of electric power generation

6

Goal of SKYACTIV engines

A carB car

C car average15%

30%

45%

0%

Electric power consumption of C car in the real world: 21.2kWh/100km.Fuel consumption of Mazda 2L C car in the real world: 5.2L/100km

10 12 14 16 18 2010

12

14

16

18

20

22

24

26

28

30

Specific electricity consumption at NEDC (kWh/100km)

3

4

5

6

7

3 4 5 6 7

I2 0.9L

I3 I.0L

I3 0.9L

1.4L

I3 1.0L

1.2L

1.4L

A 1.8L1.6L

1.4L1.6L1.6L

1.2LI3 1.0L

1.4L1.6L

1.2L

1.6L

2.0L

1.4L

1.6L

1.4L

*Source : ADAC EcoTest NEU ab März 2012

1.4L

1.2L

Mazda3 2.0L SKYACTIV-G

Note I3I.2L

1.2L

F/E at NEDC (L/100km)

A car

B car

C car

7

Fuel consumption reduction target for ICE powered vehicle in real world

21.2kWh/100km


0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00

20

40

60

80

100

120

140

Specific CO2 emission of electric power generation kg/kwh

Wel

l-to-

Whe

el_C

O2

(g/k

m)

4L/100km

3L/100km

Average

21.2kwh/100km=C car in the real world

Fuel consumption reduction target for ICE powered vehicle in real world

LCA considering just Li-ion Battery manufacturing2 ton (minimum estimation ever found)CO2 for 20kWh batteryLifetime mileage assumed 200,000km

Mazda3 2.0L = 5.2L/100km

Target for Mazda 3 5.2L/100km 4L (3.8L-4.2L)/100kmAround 25% fuel consumption reduction required

3.8L/100km

8

4.2L/100kmTarget; 4L/100km


Comparison of well-to-wheel CO2

Wel

l-to-

Whe

elco

2[g

-co2

/km

]

B car 1.3L B car BEV

126

93 93

57Discrepancy=39%

Discrepancy=26%

1. JC08 Hot ambient temperature 25℃ air conditioner 25℃ AUTO2. JC08 Hot ambient temperature 37℃ air conditioner 25℃ AUTO3. JC08 Cold ambient temperature -7℃ air conditioner 25℃ AUTO

Real-world CO2 emissions (In Japan)Evaluation condition: Weighted average of results of below 3 tests, considering Japanese ambient temperature distribution in a year

0

50

100

150

Fuel economy of internal combustion engines needs to be reduced by approx. 26%((126-93)/126=0.26) to attain the EV-level CO2 emissions.

9

Average energy consumption = JC08H 25℃－（（JC08H 25℃－JC08H 37℃）*0.2+（JC08H 25℃－JC08C -7℃）*0.3）/4

JC08 mode







Contents



Specificheat ratio


Compression ratio

Combustion period

Control factors

Combustiontiming


Mechanicalfriction

The most distinctive feature of 1st step gasoline engine is world highest compression ratio.

World highest CR

Friction reduction

Miller cycle 1stst

ep S

KYA

CTI

V-G

1stst

ep S

KYA

CTI

V-D

2ndst

ep S

KYA

CTI

V-G

2ndst

ep S

KYA

CTI

V-D

3rd

step

=Goa

l

Current Current

11

SKYACTIV engines: 1st step

1212

Full load Performance

Competitors scatter band

EU B 2.0LEU B 2.0L

Improve low- and-mid end torque in spite of a high compression ratio and achieve superior driving

0 1000 2000 3000 4000 5000 6000 7000

Engine Speed (rpm)

Torq

ue (N

m)

95RON

圧縮比＝１４

15% improved to current 2.0L

SKYACTIV-G 2.0L CR=14SKYACTIV-G 2.0L CR=14

former2.0L GEformer2.0L GE

20Nm


13

20Nm

1000 2000 3000 4000 5000 6000 7000Engine Speed (rpm)

Torq

ue (N

m)

SKYACTIV-G（4-2-1）９５RON CR＝１４

Performance enhanced together with high compression ratio

former DI 91RONCR=11.2

former PFI 91RONCR=10

Compression ratio vs. RON

SKYACTIV-G（4-2-1）91RON CR＝１3


14

50g/kWh

0 200 400 600 800 1000 1200 1400

BMEP（kPa)

1500rpm

D 2.0L

B 2.0L DIlean burn

A 2.0LDI T/C

E 2.0L DI

C Downsizing

SKYACTIV-G surpasses competitors’ all new engines including 30% downsized engines in fuel efficiency.

BSFCB

rake

spe

cific

fuel

co

nsum

ptio

n（g/

kWh)

SKYACTIV-G 2.0LSKYACTIV-G 2.0L


15

SKYACTIV-G made a large improvement in performance over conventional engines.

50g/kwh

0 200 400 600 800 1000 1200 1400BMEP (kPa)

BSFC

(g/k

wh)

1500rpm

old PFI CR=10

SKYACTIV-G(4-2-1) 95RON CR=14

SKYACTIV-G(4-2-1) 91RON CR=13

old DI CR=11.2

BSFC vs. CR







Contents


Further reduction

LeanＨＣＣＩ

Adiabatic

Higher CR

LeanＨＣＣＩ


Specificheat ratio


Compression ratio

Combustion period

Control factors

Combustiontiming


Mechanicalfriction

Gasoline engine and diesel engine will look similar in the future.

Adiabatic

Further reduction

Friction reduction

More homogeneous

World lowest CR

TDC combustion

TDC combustion

World highest CR

Friction reduction

Miller cycle 1stst

ep S

KYA

CTI

V-G

1stst

ep S

KYA

CTI

V-D

2ndst

ep S

KYA

CTI

V-G

2ndst

ep S

KYA

CTI

V-D

3rd

step

=Goa

l

Current Current

Better mixing

17

SKYACTIV engines: Next step

There is room for improving thermal efficiency in the light load range:Approx. 30% for diesel engines Approx. 40% for gasoline engines 18

Light load： 2000rpm – IMEP290kPaWalk of efficiency improvement

Combustion period GE:DE:

Specific heat ratioGE:

DE:

Compression raio GE:DE:

Wall heat transfer GE:DE:

Intake valve close GE: DE:93deg ABDC 36deg ABDC

Base ← ←Base ← ← ←

40deg 30deg←

← ←

Homogeneous

Stratified

←← Homogeneous

←

14 ← ← 20 30

-λ=1

λ=2.8 λ=2.8 λ=4

0.5*GE

40

45

50

55

60

Gasoline (GE) Diesel (DE)

75deg -

-

-


It seems possible for ICEs to attain a 25% fuel economy improvement, which is the target to to attain the EV-level CO2

Brake Specific Fuel Consumption

19

Target for 2nd step

100g/kwh

0

Target for 3rd step

200 400 600 800 1000BMEP (kPa)

32%

40%20%

34%

12%

30%

1st step SKYACTIV

Boosted lean-burn

Target for Mazda 3 5.2L/100km 3.8L-4.2L/100kmaround 25% fuel consumption reduction required


competitors

20

Motor drive using electricity generated by engine = Large battery and large motor required

generator

battery

engine

Energy flow

motorloss

Hybridization requirement on electric device capacity

Regenerative energy just delivers10-30% of vehicle driving energy

loss

loss

0 100 200 300 400 500 600 700 800BMEP （kPa）

BSF

C

Engine best efficiency point

Actual efficiency

900

Regenerative energy at deceleration

Electricity generated by engine

Motor drive Motor drive

Electricity generated by engine


21

When Mazda’s next-generation engines are hybridized, small-sized motor and battery are sufficient enough to power engines.

Hybridization requirement on electric device capacity

0 100 200 300 400 500 600 700 800BMEP （kPa）

BSF

C

900

by engine

Motor drive

Brake energy at deceleration

Motor drive

Current Hybrid

2nd step engines

Where motor drive electricity generated

Motor drive







Contents

0 20 40 60 80100120140160180200220240

Torque (Nm)

4000rpm 95RON

2.5L NA ε=13

1L T/C ε=10

180200220240260280300320340360380400

0 20406080100120140160180200220240

BSFC

(g/k

Wh)

Torque (Nm)

2000rpm 95RON2.5L NA ε=13

1L T/C ε=6

1L T/C ε=10

Prediction of BSFC

1L T/C ε=6

At low load , 1L boosted engine with usual CR=10 shows better BSFC than 2.5L NA, but at mid. and high load, 2.5L engine shows much better BSFC than 1L boosted engine.

Investigation results of boosted downsizing engines

24

Downsizing is favorable for NEDC-mode fuel economy

0

40

80

120

160

200

500100015002000250030003500400045005000

Torq

ue (

Nm

)

engine speed [rpm]

0

40

80

120

160

200

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Torq

ue [N

m]

engine speed [rpm]

Mode fuel distribution map

NEDC FTP


Real world fuel economy

SKYACTIV engines are better than boosted downsizing engines in the real world fuel economy.

3

4

5

6

7

3 4 5 6 7

0.9L

I.0L0.9L

1.4L 1.0L

1.2L

1.4L

A 1.8L 1.6L

1.4L1.6L1.6L

1.2L1.0L1.4L1.6L

1.2L

1.6L

2.0L 1.4L

1.6L

1.4L

*Source : ADAC EcoTest NEU ab März 2012 1.4L

1.2L


I.2L

1.2LBoosted D/S2 or 3 cyl or cyl. deactivation

F/E at NEDC (L/100km)


CX-5 2.0L SKYACTIV-G



Comparison between 2L SKYACTIV and 1L and 1.4L boosted D/S

2L SKYACTIV engine can be superior to 1.4L boosted D/S engine with a cylinder deactivation system, and 1L 3 cylinder boosted D/S engine in all operational ranges.

0 20 40 60 80 100 120 140 160 180 200

BSFC

(g/k

wh)

Torque (Nm)

1500rpm 95RON

1L D/S

1.4L D/S w/ cyl. Deact.

SKYACTIV current

SKYACTIV cylinder deactivation


1L D/S

SKYACTIV planned imp.


Even 2.5L SKYACTIV engine can be superior to 1.4L 4-cylinder boosted D/S engine with a cylinder deactivation system, and 1L 3 cylinder boosted D/S engine in all operational ranges.


1.0L D/S

SKYACTIV 2.5L

↑ w/ cyl. Deac.


1.0L D/S

SKYACTIV 2.5L↑ w/ cyl. Deac.

Comparison between 2.5L SKYACTIV and 1L and 1.4L boosted D/S


Base engine（Direct Injection）

Strengthened piston ,con-rod, crankshaft, block, head

Turbocharger

Intercooler & piping

Boosted D/S

Electric VCT

4-2-1 exhaust

SKYACTIV-G

Cost

Boosted downsizing engines require extra expensive devices.


100g/kwh


Current V6 3.7L

V6 3.7L SKYACTIV

T/C I4 2.5L SKYACTIV

Turbocharged I4 SKYACTIV vs. NA V6 SKYACTIV

The most efficient way to downsize engines is to convert V engines to inline engines and downsize, while controlling knocking in the high load range with specific technologies to boosted engines.

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 1000 2000 3000 4000 5000

Frict

ion

ratio

Displacement [cc]

6 cylinders4cylinders

2.5L 3.7L

V6⇒V6

I4⇒I4V6⇒I4

Effect of friction reduction by downsizing and cylinder number reduction

Mechanical friction reduction due to downsizing 3.7 L V6 to 2.5 L I4 is 1.6-times greater than downsizing 3.7 L V6 to 2.5 L V6 or 3.7 L I4 to 2.5 L I4. As a result, fuel economy is significantly improved.

Mechanical friction reduction due to downsizing 3.7 L V6 to 2.5 L I4 is 1.6-times greater than downsizing 3.7 L V6 to 2.5 L V6 or 3.7 L I4 to 2.5 L I4. As a result, fuel economy is significantly improved.


Cost comparison between NA V6 SKYACTIV and Turbocharged I4 SKYACTIV

T/C I4 SKYACTIVNA V6 NA V6 SKYACTIV


• To convert a NA V6 engine to a T/C I4 SKYACTIV engine with 4 cylinders, costs of some devices, such as an electric VVT, a high-pressure fuel rail and others will be halved than to convert a V6 engine to a V6 SKYACTIV engine.

• The cost of an injector and coils will be reduced to two-thirds.• When an inlet 4-cylinder engine is converted to a inlet 4-cylinder SKYACTIV engine, the cost of

additional devices are unchanged. The cost is raised due to a turbocharger.• In the case of a 3-cylinder engine, only costs of parts for one cylinder are saved.

• To convert a NA V6 engine to a T/C I4 SKYACTIV engine with 4 cylinders, costs of some devices, such as an electric VVT, a high-pressure fuel rail and others will be halved than to convert a V6 engine to a V6 SKYACTIV engine.

• The cost of an injector and coils will be reduced to two-thirds.• When an inlet 4-cylinder engine is converted to a inlet 4-cylinder SKYACTIV engine, the cost of

additional devices are unchanged. The cost is raised due to a turbocharger.• In the case of a 3-cylinder engine, only costs of parts for one cylinder are saved.

Excess air ratio vs. thermal efficiency NOx vs. excess air ratio

Expanding Λ>2.2 is required for the compatibility of both efficiency and no NOX after-treatment

0246810

0 0.5 1 1.5 2 2.5 3 3.5

NO

xEI

90010001100120013001400

BMEP (kPa)

0246810

NO

xEI

100150200250300350

BMEP (kPa)Light Load

High load2000rpmCR＝14Combustion duration＝35°

35

40

45

50

55

0 2 4 6 8 10 12Excess air ratio

Indi

cted

ther

mal

effi

cien

cy (

%)

300kPa600kPa900kPa

IMEP

Excess air ratio

Future strategy for engine displacement

Target of lean burn

2000rpm

180200220240260280300320340360380400

0 20 40 60 80 100 120 140 160 180 200 220 240

BSFC (g/kWh)

Torque (Nm)

50403020100 1L turbo CR=10 λ=1

1L turbo CR=10 lean 2.5L NA CR=13 λ=1 2.5L NA CR=13 lean

Λ=2.2

Λ=1 EGR

Λ=1 EGR

Lean burn capable area against displacement

Large Disp. NA can enlarge lean-burn area wider than boosted downsizing.Boosted Upsizing for wide lean-burn area is recommendable

32

01

-1

Future strategy for engine displacement

Examination of fuel economy


July 2008

Averaged mileage/year is somewhere between 10,000 and 15,000 km. (US excluded.)

Average mileage /year

Country

Japan

United States

England

Germany

France

Vehicle age（years）

9,896

18,870

14,720

12,600

5,84

8,30

6,20

6,75

14,100 7,50

Ref.）report from investigative commission on c lean diesel passenger car growth・future prospect

Mileage/year (km)

1 Ford Fusion SE Hybrid 39 35 412 Toyota Camry Hybrid XLE 38 32 433 Volkswagen Passat TDI SE 37 26 514 Hyundai Sonata Hybrid 33 24 405 Mazda6 Sport 32 22 446 Nissan Altima 2.5 S (4-cyl.) 31 21 447 Honda Accord LX (4-cyl.) 30 21 408 Chevrolet Malibu Eco 29 20 419 Toyota Camry LE (4-cyl.) 27 19 4110 Hyundai Sonata GLS 27 18 39

11 Subaru Legacy 2.5i Premium 26 18 35

12 Chevrolet Malibu 1LT 26 17 3813 Toyota Camry XLE (V6) 26 17 3714 Honda Accord EX-L (V6) 26 16 39

COMBI CITY HWY

Midsized cars

Real world fuel economy (US)

Fuel economy (mpg)

Consumer report 2013

Fuel economy of HEV is superior , however,…

1 Honda Civic Hybrid 40 28 50

2 Volkswagen Jetta Hybrid SE 37 29 45

3 Volkswagen Jetta TDI 34 25 45

4 Mazda3 i Touring sedan 33 23 45

5 Chevrolet Cruze Turbo Diesel 33 22 49

6Mazda3 i Grand Touring hatchback 32 24 41

7 Toyota Corolla LE Plus 32 23 438 Ford Focus SE SFE 31 21 43

9 Volkswagen Jetta SE (1.8T) 30 21 39

10 Nissan Sentra SV 29 21 3811 Honda Civic EX 29 20 4012 Hyundai Elantra GLS 29 20 3913 Dodge Dart Rallye 29 19 41

COMPACT CARS Overall mpg = 29 or higher

COMBI CITY HWYFuel economy (mpg)


0500

100015002000250030003500400045005000

0 10 20 30 40 50 60 70 80 90 100

14001150

mpg

Mid size cars 1400-1150=250$/year

Compact cars1358-1121=237$/year

Mid size conventionalMid size HEV


Fuel cost / yearassuming 19,000km /year gasoline price; 3.8$/gallon

Average drive cannot payoff the price increase by HEV by superior fuel economy

Summary

38

• We created roadmaps toward the ideal ICE and are steadily advancing developments accordingly.

• We introduced the world’s highest compression ratio into the gasoline engines at the first step.

• We believe that our approach is more reasonable than the boosted downsizing approach from a perspective of real-world fuel economy and cost.

• We believe that hybrid-level fuel economy is achievable with just improving ICE technologies and that EV-level CO2 emissions is also achievable with improved ICE and simple hybrid technologies.

• We believe that the EV-level of well-to-wheel CO2 emissions is achievable with approx. 25% improvements from that of the current SKYACTIV. Once EVs have held a large share of the market, tremendous amount of electricity will have to be generated. As a result, EVs will be unable to obtain benefits from the current electric price due to the electric price increase.

• We regard large engine displacement as a cost free turbocharger, and plan to maximize its advantage and increase engine displacement.

• If expensive technologies which only improve fuel economy are offered to our customers, they cannot pay off high vehicle prices. Therefore, we continuously offer technologies together with additional values, such as driving pleasure.

Thank you for your attention!

ConclusionConclusion

1. Boosted downsizing engines show better BSFC at a light load. However, large displacement NA engines (SKYACTIV) show the better BSFC at a mid-and-high load due to higher compression ratios.

2. With introduction of cylinder deactivation systems into large-displacement NA engines, NA engines show better BSFC in all the operational ranges. The 2.5L NA engines beat the 1 liter turbo engines in both F/E and power performance.

3. Large-displacement NA engines have demonstrated their advantages in the real world fuel economy over boosted D/S engines.

4. It is clear that NA engines cost less than boosted D/S engines.

5. Further drastic improvements in thermal efficiency is possible with introduction of lean-burn technologies. It is easer to expand the lean burn area of large displacement engines.

The best direction is upsizing.

• Fossil fuel reserve production said to be more than 170 years. (Source: World energy outlook 2011)

• Please assess CO2 on the well-to-wheel basis.• Please bear in mind that establishing low CO2 electric power

generation must come first before giving much incentives and prepare many electric chargers to expand EV use. This is the same for FCVs (fuel cell vehicles)

• It is possible to improve ICEs to achieve the well-to-wheel CO2 equal to that of EVs.

Drastic improvements of ICE efficiency are the most realistic way to improve the environment until a sustainable new energy source is developed.

Additional message

The 2nd step engine targets higher CR & leaner CAI.

Further thermal efficiency improvement


42

10 14 18 221

2

3

4

5

6

7

8

圧縮比ε

空気過剰率 λ

48%

48%

46%

46%

44%

44%42%

42%

2000rpm/200kPa

Compression ratio

Excess air ratio λ

SISI

CAICAI

λ=2.0

λ=2.5

SI lean-burn is not feasible at λ>2

NOx=0 λ>2.2

Comparison of thermal efficiency improvement

20

30

40

50

60[%

]

Engine Efficiency

020406080

100120

580 680 780 880 980 1080 1180

[km

/h]

Time [sec]

Vehicle Speed

1st step

2nd step

3rd step

60

70

80

90

100

[%]

Motor and Battery Efficiency

ICE vehicles will be able to attain the CO2 level of EVs based on mode simulation. Efficiency improvement for EVs is nearing its limit.

43


Targeted CO2 reduction level by ICE improvement

Aiming at CO2 level of EVs by ICE improvement

※Calculated based on Electric generation life cycle by Central Research Institute of Electric Power Industry(2010)0

50

100

Wel

l-to-

Whe

el C

O2

g-C

O2/

km

HEV150

EVICE（including vehicle improvement）

1st step

2nd step

3rd step

SKYACTIV-G1

Former model

Non thermal power generation

37%

Mazda2 EV (1180kg)100Wh/km

2010 actual

0%

Case study Mazda2 JC08

44

SKYACTIV-G2

SKYACTIV-G3


0

50

100

150

Wel

l-to-

whe

el C

O2

-g/k

m

EPA

CARB

1st step

Wel

l-to-

whe

el C

O2

-g/k

m

ICE HEV EV

US CombiC-Segment including vehicle improvementCO2/Gasoline 2.32kg/L

Targeted CO2 reduction level by ICE improvement

US average level of CO2 is achievable.

SKYACTIV-G1

SKYACTIV-G2

SKYACTIV-G3


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