Mazda SKYACTIV-G Engine with New Boosting Technology

- ACC Symposium held on September 28 -

Reiji Okita Mazda Motor Corporation 28, Sep. 2016 CONTENTS 1. Mazda’s approach for environmental improvement 2. SKYACTIV-G Development Process 3. SKYACTIV-G 2.5L TC development 4. End message

Mazda’s Long-term Vision “Sustainable Zoom-Zoom“ Provide all the customers with driving pleasure, Also, Mazda considers the best contribution to the environment is to incorporate superior and fairly valued technologies into every car model rather than expensive eco technologies to limited models Mazda’s approach 100% 100% Small number of expensive eco-vehicles CO 2 CO 2

0% 0% a b c d e f g h i j a b c d e f g h i j

Vehicles ©Vehicles Mazda Motor Corporation │ Strictly Confidential │ 3 Why we believe so ? 1) Market forecast 2) Difference between Well-to-Wheel CO2 emissions of EV and ICE

Tank to Wheel Well to Wheel

CO2 CO2 CO2

Wheel Well Tank Wheel

© Mazda Motor Corporation │ Strictly Confidential │ 4 1. Mazda’s approach for environmental improvement - Market forecast- Vehicle Sales by type Vehicle Sales Volume by region Ref. BP Energy Outlook 2035 Ref. Marubeni Research Institute 250

BEV 200 PHEV Non-OECD 150 : Others

ICE Non-OECD Internal Combustion Engine 100 : ASIA

50 OECD

・・・ GE/DE (million) /year volume Sales

0 2000 2010 2020 2030 2040 2050 Most of power source of a car which will increase in future are internal combustion engines. It will not be possible to make a contribution for environment without improving internal combustion engines. 5 1. Mazda’s approach for environmental improvement - Well to Wheel - Well to Tank CO2 emission of Electricity (withoutCO2排出原単位（発電端）の各国比較 transmission efficiency)

0.5kg-CO2/kWh by basic unit bybasic CO2emissions

France Canada Italy England Japan German US China India

Well to Tank of Fuel in Japan energies Nuclear 0.37kg-CO2/L Water

Breakdown of non-fossil non-fossil of Breakdown New energy, others

We assume that global average of specific CO2 emission in electric power generation is 0.5kg-CO2/kWh © Mazda Motor Corporation │ Strictly Confidential │ 6 1. Mazda’s approach for environmental improvement - Well to Wheel - Electricity Consumption and Fuel Consumption 7 30 *Source : ADAC EcoTest 1.4L 1.6L NEU ab März 2012 2.0L 1.6L 28 A 1.8L 1.2L 1.4L 1.2L 26 1.6L 6 1.6L 45% 1.6L 1.4L 24 I3 1.0L 1.4L 1.2L 1.4L 1.6L I2 0.9L 1.4L I3 1.0L 22 C car average 30% 1.4L 1.2L NoteI3 I3 0.9L 1.2L 21.2kWh/100km 15% 5 5.2L/100km I.2L 20 I3 I.0L Mazda3 18 B car 0% 2.0L SKYACTIV-G A car 16 4 15% 14 A car

B car testECO ADAC F/E (L/100k) 0% 12 Specific Specific electricity consumption at ADAC ECO test (kWh/100km) test ECO ADAC at C car 10 3 10 12 14 16 18 20 3 4 5 6 7 Specific electricity consumption at NEDC (kWh/100km) F/E at NEDC (L/100km)

C car EV Real World Electricity Consumption : 21.2kWh/100km

C car SKYACTIV-G Real World Fuel Consumption：© Mazda5.2L/100km Motor Corporation │ Strictly Confidential │ 7 1. Mazda’s approach for environmental improvement - Well to Wheel Well to Wheel CO2 emission 〜Mazda Estimate C car EV Electricity Consumption: 21.2kWh/100km Specific CO2 emission : 0.5 CO2-kg/kWh + LCA considering Li-ion Battery: 1.0kg/100km

106 〜 116 CO2-g/km

C car SKYACTIV-G Fuel Consumption : 5.2L/100km 20% - 30% （Well to tank + Tank to Wheel) 148 CO2-g/km

If the fuel consumption could be improved by 20%-30%, CO2 emission level of the vehicle powered by ICE could be equal to that of EV. © Mazda Motor Corporation │ Strictly Confidential │ 8 1. Mazda’s approach for environmental improvement

Potential of the improvement Well to Wheel CO2 emission with ICE

Current efficiency of Tank-to-Wheel EV : 80%-90% ICE: max. 30% - 40%

There is still Large potential of improvement in ICE, also hybridization gives further improvement on ICE

How do we let the aim accomplish ? “F/C improvement 20%〜30%”

Innovative High Thermal Efficiency

The energy of the fuel is converted to power that moves the vehicle.

Maximize

Improvement of driving force Improvement of fuel economy Decrease of poisonous substance in exhaust gas

High-efficient Engine ← Minimize Losses

Heat energy balance vs. load Control factor 100 Radiation, Misfiring loss

Compression ratio Exhaust loss 80 Specific heat ratio

Combustion period 60 Cooling loss Combustion timing

40 Heat insulation Heat Energy Heat Energy Balance (%) Mechanical loss 20 Pressure difference Effective work b/w intake and exhaust

0 20 40 60 80 100 Load (%) © Mazda Motor Corporation │ Strictly Confidential │ 13 2. SKYACTIV-G Development Process

Roadmap to the goal of ICE Far Distance to ideal Close

Gasoline engine Diesel engine Control factors current current

Compression World Higher World ratio highest CR lowest CR CR Specific Lean More Better heat ratio HCCI homogeneous mixing

Combustion TDC period combustion step=Goal Combustion

rd TDC

timing SKYACTIV-G SKYACTIV-G 3 combustion SKYACTIV-D SKYACTIV-D

Heat transfer adiabatic to wall step step step step

st Lean Pressure diff. Miller st 1 nd nd Btw IN. & Ex. HCCI 1 cycle 2 2

Mechanical friction Further Further friction friction reduction reduction reduction reduction

Gasoline and diesel engines will look similar in th©e Mazda future. Motor Corporation │ Strictly Confidential │ 14 3. SKYACTIV-G 2.5L TC development Power Source for CD-SUV Previous New Generation Generation or 400 V6 I4 Boosted 2.3L_T/C TORQUE 3.7L_V6 2.5L Nm 2.5L 200 2.0L HIGH CR NA 2.0L/1.8L 1.5L Inline four (4) 1.6L/1.5L 1.3L 1.3L

TIME-LINE Alternative delivering torque higher than 400Nm on a large SUV is, V6 Natural Aspirated or Boosted I4 downsized. © Mazda Motor Corporation │ Strictly Confidential │ 15 CONTENTS 1. Mazda’s approach for environmental improvement 2. SKYACTIV-G Development Process 3. SKYACTIV-G 2.5L TC development 4. End message

© Mazda Motor Corporation │ Strictly Confidential │ 17 3. SKYACTIV-G 2.5L TC development Advantage of I4 boosted Effect of Downsizing V6 3.7L ⇒⇒⇒ Boosted I4 2.5L Mechanical Friction ～Calculation by Mazda

Compared to V6 3.7L, boosted I4 2.5L achieves: - 30% less mechanical friction with fewer cylinders (6 to 4) and less displacement © Mazda Motor Corporation │ Strictly Confidential │ 18 3. SKYACTIV-G 2.5L Turbocharged (TC) Engine Development Advantage of I4 boosted Effect of Downsizing V6 3.7L ⇒⇒⇒ Boosted I4 2.5L Pumping loss

Compared to the V6 3.7L, the boosted I4 2.5L achieves: - 30% less pumping loss with less displacement. © Mazda Motor Corporation │ Strictly Confidential │ 19 3. SKYACTIV-G 2.5L TC development

I4 boosted concept has superior mechanical friction and pumping loss, while it is inferior fuel efficiency due to lowered compression ratio, and acceleration response.

Key issue to realize I4 boosted with high compression ratio is Knocking Resistance Improvement

Evaluation Tool for calculation of knocking resistance

Ignition delay

Livengood-Wu integral P: pressure (kPa) T: unburned gas temp. (K) X_EGR ：EGR ratio

Compression ratio setting Compression ratio setting in the high load range in the light load range Anti-knocking @2000rpm technology 4.0 BSFC ε=13.0 ε=10.5 Pumping Loss 3.5 Improvement ε=9.0 ε=8.0 ε=13 Mechanical 3.0 ε=7.0 ε=6.0 Resistance 2.5 ε=5.0 ε 2.0 =10.5 BSFC 1.5 ε=8 Maintain 2.5L TC knock resistance LW Integral 1.0 [-] ε=6 equivalent to NA 0.5 LW integral value V6 3.7L V6 2.5L I4 2.5L I4 2.5L I4 2.5L at BLD of 2.5L NA CR=13 =8 0.0 ε=13 ε=13 ε=13 ε=10.5 ε 0.5 1.0 1.5 2.0 2.5 3.0 3.5 （（（2.5L ））） Displacement Charging pressure [bar] To keep the advantage of I4 turbocharged engine for the mechanical friction and pumping loss, the compression ratio must be kept around 10.5. © Mazda Motor Corporation │ Strictly Confidential │ 22 Cascaded targets to realize compression ratio, 10.5

The concept o improve knock resistance at high loads, encouraging “scavenging” for low speed and introducing EGR for mid/high speed.

“Scavenging” at low rpm/high load “EGR” at mid/high rpm & high load @1500rpm @4000rpm

Heavy knocking area Heavy knocking area ε=13.0 ε=13

ε=10.5 ε=10.5 BGR 7.0%

ε=10.5 -75K BGR 2.5% ε=10.5 EGR18% EGR18% ε=10.5 ε=10.5 BGR 0.0% EGR25%

(2.5L) ------Displacement (2.5L) ------Displacement

The follows are necessities for the turbo charged 2.5L engines(CR 10.5/boost pressure 2.0bar) to ensure the knock resistance equivalent to 2.5L NA engines(CR 13.0) . - low rpm/high load : TDC Temp.Δ75K, BGR* 7.0% →2.5% - mid/high rpm & high load: EGR ratio 18% *: BGR = Residual gas ratio © Mazda Motor Corporation │ Strictly Confidential │ 25 Specific Measures to achieve cascaded specific targets

Overlap Interval High Pulsation makes high boost

Boost Pressure Pressure

Exhaust pressure

Crank angle PressureGap

EVO IVO

For strong scavenging, a large gap of pressure and long overlap interval are necessary, while the boost pressure exceeding over exhaust gas pressure.

Dynamic Pressure Turbo (DPT) Structure B-B cross section

A-A cross section

To realize scavenging concept, 4-3-1 exhaust was adopted so that the volume of four exhaust passages are minimized evenly. Each passage is divided into primary and secondary in order to encourage turbine rotation and scavenging effect. © Mazda Motor Corporation │ Strictly Confidential │ 28 3. SKYACTIV-G 2.5L TC development

Dynamic Pressure Turbo (DPT) Scavenging Effect

Dynamic Pressure Turbo (DPT) effect at low/high engine rev.

HP-Cooled EGR Passage

EGR Cooler

DPT Control Valve

EGR pipe

EGR gas is pulled through EGR outlet placed at down stream of the control valve, and brought to EGR cooler.

© Mazda Motor Corporation │ Strictly Confidential │ 31 3. SKYACTIV-G 2.5L TC development Function of EGR Pipe Location Scavenging condition No Scavenging condition & no EGR required & enough EGR required Low rpm High pulsation Mid/High rpm High load Pressure Pressure Low pressure Low pulsation

EGR Valve : Open Valve : Close EGR pipe EGR pipe

EGR passage does not disturb “scavenging” effect when it is required, but able to provide sufficient amount of EGR with transient accuracy. © Mazda Motor Corporation │ Strictly Confidential │ 32 3. SKYACTIV-G 2.5L TC development Scavenging and EGR Area

SKYACTIV-G with DPT achieved to enable high scavenging under low engine speed, as well as introduce high amount of EGR in wider engine operation range, led significantly low fuel consumption performance.

Reduction in Fuel Consumption

SKYACTIV-G 2.5L with DPT improves the fuel efficiency over a whole range.

Torque Curve Acceleration Characteristic

SKYACTIV-G 2.5L with DPT achieved significantly higher torque than predecessor from low engine speed under 91RON, as well as much shorter turbo lag.

SKYACTIV-G 2.5L with DPT λ=1 window 500 240km/h 6th 450 SKYACTIV -G 2.5T 5th WOT 220km/h 400 200km/h 2.3L TC WOT 350 1 V6 3.7L WOT 300 180km/h

250 160km/h 2 Torque [Nm] Torque 200 140km/h 120kW 110kW 150 120km/h 100kW 100km/h 100

0 0 1000 2000 3000 4000 5000 6000 7000 Engine Speed [rpm]

SKYACTIV-G 2.5L with DPT achieved wider range of λ=1 window, real-world fuel consumption has been improved by 30% from the predecessor model.

Summary Mazda 2.5L SKYACTIV-G Engine with “Dynamic Pressure Turbo” and “HP cooled-EGR” brought the following benefits: 1. Acceleration response comparable to that of large- displacement naturally aspirated engine 2. Low fuel consumption at middle and high loads.

3. The maximum torque of 420 Nm at low speed, 2000rpm

© Mazda Motor Corporation │ Strictly Confidential │ 39 ICE has still enough potential to improve its thermal efficiency. Mazda continues to improve ICE performance targeting to equal CO2 emission level as EV’s.