2015 ERC Symposium Mitsuo Hitomi Mazda Motor Corporation

Transcription

1 Mazda s Approach for Developing Engines from a Perspective of Environmental Improvement 2015 ERC Symposium Mitsuo Hitomi Mazda Motor Corporation

2 Contents Improving thermal efficiency of ICEs Goal of SKYACTIV engines SKYACTIV engines: 1 st step SKYACTIV engines: Next step Investigation results of boosted downsizing engines and future strategy for engine displacement

3 Improving thermal efficiency of ICEs Energy losses of ICE 100 Heat Energy Balance vs. Load Radiation, Misfiring loss Control factors Compression ratio Heat Energy Balance (%) Exhaust loss Cooling loss Pumping loss Specific heat ratio Combustion period Combustion timing Heat transfer to wall 20 0 Mech. friction loss Effective work Load (%) Pressure difference between In. & Ex. Mechanical friction Fuel Economy Improvement=Loss reduction All technologies for improving fuel economy must overcome these seven controlling factors. 3

4 Improving thermal efficiency of ICEs Roadmap to the goal of ICE Far Distance to ideal Close Control factors Current Gasoline engine Diesel engine Current Compression ratio World highest CR Higher CR World lowest CR Specific heat ratio Combustion period Combustion timing Heat transfer to wall Pressure diff. Btw IN. & Ex. Miller cycle 1 st step SKYACTIV-G Lean HCCI Lean HCCI 2 nd step SKYACTIV-G Adiabatic 3 rd step=goal 2 nd step SKYACTIV-D Adiabatic More homogeneous 1 st step SKYACTIV-D Better mixing TDC combustion TDC combustion Mechanical friction Friction reduction Further reduction Further reduction Friction reduction Gasoline engine and diesel engine will look similar in the future. 4

5 Contents Improving thermal efficiency of ICEs Goal of SKYACTIV engines SKYACTIV engines: 1 st step SKYACTIV engines: Next step Investigation results of boosted downsizing engines and future strategy for engine displacement

6 Goal of SKYACTIV engines Specific CO2 emissions of electric power generation (kg-co2/kwh) After 2011 big earthquake in Japan France Canada Japan Italy UK Germany USA China India Specific CO2 emission from electric power generation is assumed to be 0.5kg-CO2/kWh. 6

7 Goal of SKYACTIV engines Fuel consumption reduction target for ICE powered vehicle in real world C car average 21.2kWh/100km B car A car 45% 30% 15% 0% A car B car C car Specific electricity consumption at NEDC (kwh/100km) F/E at NEDC (L/100km) 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 *Source : ADAC EcoTest NEU ab März L 1.6L 1.6L 1.4L I3 1.0L 1.4L 1.2L 1.4L 1.6L I2 0.9L 1.4L I3 1.0L 1.4L 1.2L Note I3 I30.9L 1.2L I.2L I3 I.0L 1.4L 1.6L 2.0L A 1.8L 1.6L 1.2L 1.4L 1.2L Mazda3 2.0L SKYACTIV-G 7

8 Goal of SKYACTIV engines Fuel consumption reduction target for ICE powered vehicle in real world Average Mazda3 2.0L = 5.2L/100km Well-to-Wheel_CO2 (g/km) Target; 4L/100km 21.2kwh/100km =C car in the real world 4.2L/100km 3.8L/100km 4L/100km 3L/100km LCA considering just Li-ion Battery manufacturing 2 ton (minimum estimation ever found)co2 for 20kWh battery Lifetime mileage assumed 200,000km Specific CO2 emission of electric power generation kg/kwh Target for Mazda 3 5.2L/100km 4L (3.8L-4.2L)/100km Around 25% fuel consumption reduction required 8

9 Goal of SKYACTIV engines Real-world CO2 emissions (In Japan) Evaluation condition: Weighted average of results of below 3 tests, considering Japanese ambient temperature distribution in a year 1. JC08 Hot ambient temperature 25 air conditioner 25 AUTO 2. JC08 Hot ambient temperature 37 air conditioner 25 AUTO 3. JC08 Cold ambient temperature -7 air conditioner 25 AUTO Average energy consumption = JC08H 25 -((JC08H 25 -JC08H 37 )*0.2+(JC08H 25 -JC08C -7 )*0.3)/4 Well-to-Wheel co2 [g-co2/km] Comparison of well-to-wheel CO2 Discrepancy=26% B car 1.3L JC08 mode 57 B car BEV Discrepancy=39% 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

10 Contents Improving thermal efficiency of ICEs Goal of SKYACTIV engines SKYACTIV engines: 1 st step SKYACTIV engines: Next step Investigation results of boosted downsizing engines and future strategy for engine displacement

11 SKYACTIV engines: 1 st step Roadmap to the goal of ICE Far Distance to ideal Close Control factors Current Gasoline engine Diesel engine Current Compression ratio World highest CR Specific heat ratio Combustion period Combustion timing Heat transfer to wall Pressure diff. Btw IN. & Ex. Miller cycle 1 st step SKYACTIV-G 2 nd step SKYACTIV-G 3 rd step=goal 2 nd step SKYACTIV-D 1 st step SKYACTIV-D Mechanical friction Friction reduction The most distinctive feature of 1 st step gasoline engine is world highest compression ratio. 11

12 SKYACTIV engines: 1 st step Full load Performance SKYACTIV-G 2.0L 圧縮比 =14 CR=14 20Nm 15% improved to current 2.0L Torque (Nm) EU B 2.0L former2.0l GE Competitors scatter band 95RON Engine Speed (rpm) Improve low- and-mid end torque in spite of a high compression ratio and achieve superior driving 12 12

13 SKYACTIV engines: 1 st step Compression ratio vs. RON SKYACTIV-G(4-2-1) 91RON CR=13 SKYACTIV-G(4-2-1) 95RON CR=14 Torque (Nm) former DI 91RON CR=11.2 former PFI 91RON CR=10 20Nm Engine Speed (rpm) Performance enhanced together with high compression ratio 13

14 SKYACTIV engines: 1 st step BSFC A 2.0LDI T/C 1500rpm Brake specific fuel consumption(g/kwh) 50g/kWh SKYACTIV-G 2.0L C Downsizing D 2.0L B 2.0L DI lean burn E 2.0L DI BMEP(kPa) SKYACTIV-G surpasses competitors all new engines including 30% downsized engines in fuel efficiency. 14

15 SKYACTIV engines: 1 st step BSFC vs. CR 1500rpm BSFC (g/kwh) 50g/kwh old PFI CR=10 old DI CR=11.2 SKYACTIV-G(4-2-1) 91RON R=13 C SKYACTIV-G(4-2-1) 95RON R=14 C BMEP (kpa) SKYACTIV-G made a large improvement in performance over conventional engines. 15

16 Contents Improving thermal efficiency of ICEs Goal of SKYACTIV engines SKYACTIV engines: 1 st step SKYACTIV engines: Next step Investigation results of boosted downsizing engines and future strategy for engine displacement

17 SKYACTIV engines: Next step Roadmap to the goal of ICE Far Distance to ideal Close Control factors Current Gasoline engine Diesel engine Current Compression ratio World highest CR Higher CR World lowest CR Specific heat ratio Combustion period Combustion timing Heat transfer to wall Pressure diff. Btw IN. & Ex. Miller cycle 1 st step SKYACTIV-G Lean HCCI Lean HCCI 2 nd step SKYACTIV-G Adiabatic 3 rd step=goal 2 nd step SKYACTIV-D Adiabatic More homogeneous 1 st step SKYACTIV-D Better mixing TDC combustion TDC combustion Mechanical friction Friction reduction Further reduction Further reduction Friction reduction Gasoline engine and diesel engine will look similar in the future. 17

18 SKYACTIV engines: Next step Walk of efficiency improvement Light load:2000rpm IMEP290kPa Gasoline (GE) Diesel (DE) Combustion period Specific heat ratio Compression raio Wall heat transfer 40 GE: DE: GE: DE: GE: DE: GE: DE: 75deg - 40deg Intake valve close GE: 93deg ABDC DE: λ=1 30deg - Homogeneous Base Base - 0.5*GE Homogeneous λ=2.8 λ=2.8 λ=4 Stratified 36deg ABDC There is room for improving thermal efficiency in the light load range: Approx. 30% for diesel engines Approx. 40% for gasoline engines 18

19 SKYACTIV engines: Next step Brake Specific Fuel Consumption Target for Mazda 3 5.2L/100km 3.8L-4.2L/100km around 25% fuel consumption reduction required 32% 100g/kwh competitors 0 20% 40% 12% 34% 30% Boosted lean-burn BMEP (kpa) 1 st step SKYACTIV Target for 2 nd step Target for 3 rd step It seems possible for ICEs to attain a 25% fuel economy improvement, which is the target to to attain the EV-level CO2 19

20 SKYACTIV engines: Next step Hybridization requirement on electric device capacity Regenerative energy just delivers10-30% of vehicle driving energy BSFC Regenerative energy at deceleration Motor drive Electricity generated by engine Actual efficiency Motor drive Electricity generated by engine Energy flow motor battery loss loss Engine best efficiency point generator engine loss BMEP (kpa) 900 Motor drive using electricity generated by engine = Large battery and large motor required 20

21 SKYACTIV engines: Next step Hybridization requirement on electric device capacity Where motor drive electricity generated Brake energy at deceleration by engine Motor drive Motor drive BSFC Current Hybrid Motor drive 2 nd step engines BMEP (kpa) 900 When Mazda s next-generation engines are hybridized, small-sized motor and battery are sufficient enough to power engines. 21

22 Contents Improving thermal efficiency of ICEs Goal of SKYACTIV engines SKYACTIV engines: 1 st step SKYACTIV engines: Next step Investigation results of boosted downsizing engines and future strategy for engine displacement

23 Investigation results of boosted downsizing engines Prediction of BSFC BSFC (g/kwh) rpm 95RON 4000rpm 95RON 2.5L NA ε=13 2.5L NA ε=13 1L T/C ε=6 1LT/Cε=6 1L T/C ε=10 1L T/C ε= Torque (Nm) Torque (Nm) 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.

24 Investigation results of boosted downsizing engines Mode fuel distribution map NEDC FTP Torque (Nm) Torqu e [Nm] engine speed [rpm] engine speed [rpm] Downsizing is favorable for NEDC-mode fuel economy 24

25 Investigation results of boosted downsizing engines Real world fuel economy *Source : ADAC EcoTest NEU ab März L 2.0L A 1.8L BoostedD/S 1.2L 2or3cylorcyl.deactivation 1.2L 1.6L 1.0L 1.6L 1.4L 1.4L 1.2L 0.9L 1.4L 1.4L 1.6L 1.0L 1.4L 1.2L I.2L 1.2L 0.9L Mazda62.0L SKYACTIV-G I.0L Mazda32.0L SKYACTIV-G Mazda32.0L SKYACTIV-G 1.6L 1.4L CX-52.0L SKYACTIV-G 1.6L F/EatNEDC(L/100km) SKYACTIV engines are better than boosted downsizing engines in the real world fuel economy.

26 Investigation results of boosted downsizing engines Comparison between 2L SKYACTIV and 1L and 1.4L boosted D/S 1500rpm 95RON SKYACTIV cylinder deactivation 1L D/S 1L D/S BSFC (g/kwh) SKYACTIV current 1.4L D/S w/ cyl. Deact. SKYACTIV planned imp. 1.4L D/S w/ cyl. Deact Torque (Nm) 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.

27 Investigation results of boosted downsizing engines Comparison between 2.5L SKYACTIV and 1L and 1.4L boosted D/S 1.0L D/S 1.4L D/S w/ cyl. Deact. SKYACTIV 2.5L w/ cyl. Deac. 1.0L D/S 1.4L D/S w/ cyl. Deact. SKYACTIV 2.5L w/ cyl. Deac. 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.

28 Investigation results of boosted downsizing engines Cost Turbocharger Base engine (Direct Injection) Boosted D/S Strengthened piston,con-rod, crankshaft, block, head Intercooler & piping SKYACTIV-G Electric VCT exhaust Boosted downsizing engines require extra expensive devices.

29 Investigation results of boosted downsizing engines Turbocharged I4 SKYACTIV vs. NA V6 SKYACTIV Current V6 3.7L 100g/kwh V6 3.7L SKYACTIV T/C I4 2.5L 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.

30 Investigation results of boosted downsizing engines Effect of friction reduction by downsizing and cylinder number reduction Friction ratio V6 I4 V6 V6 I4 I4 6 cylinders 4cylinders L 3.7L Displacement [cc] 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.

31 Investigation results of boosted downsizing engines Cost comparison between NA V6 SKYACTIV and Turbocharged I4 SKYACTIV NA V6 NA V6 SKYACTIV T/C I4 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.

32 Future strategy for engine displacement Target of lean burn Excess air ratio vs. thermal efficiency Indicted thermal efficiency (%) IMEP 900kPa 600kPa 300kPa 2000rpm CR=14 Combustion duration= Excess air ratio NOx vs. excess air ratio Expanding Λ>2.2 is required for the compatibility of both efficiency and no NOX after-treatment NOxEI NOxEI Light Load High load Excess air ratio BMEP (kpa) BMEP (kpa)

33 Future strategy for engine displacement Lean burn capable area against displacement BSFC(g/kWh) rpm Λ= L turbo CR=10 λ=1 Λ=1 EGR 1L turbo CR=10 lean 2.5L NA CR=13 λ=1 2.5L NA CR=13 lean Λ=1 EGR Torque(Nm) Large Disp. NA can enlarge lean-burn area wider than boosted downsizing. Boosted Upsizing for wide lean-burn area is recommendable

34 Examination of fuel economy

35 Examination of fuel economy Average mileage /year Country Japan United States Mileage/year (km) 9,896 18,870 Vehicle age(years) 5,84 8,30 England Germany 14,720 12,600 6,20 6,75 France 14,100 7,50 Ref.)report from investigative commission on c lean diesel passenger car growth future prospect July2008 Averaged mileage/year is somewhere between 10,000 and 15,000 km. (US excluded.)

36 Examination of fuel economy Real world fuel economy (US) Midsized cars Fuel economy (mpg) COMBI CITY HWY 1 Ford Fusion SE Hybrid Toyota Camry Hybrid XLE Volkswagen Passat TDI SE Hyundai Sonata Hybrid Mazda6 Sport Nissan Altima 2.5 S (4-cyl.) Honda Accord LX (4-cyl.) Chevrolet Malibu Eco Toyota Camry LE (4-cyl.) Hyundai Sonata GLS Subaru Legacy 2.5i Premium Chevrolet Malibu 1LT Toyota Camry XLE (V6) Honda Accord EX-L (V6) Consumer report Honda Civic Hybrid Volkswagen Jetta Hybrid SE Volkswagen Jetta TDI Mazda3 i Touring sedan COMPACT CARS Overall mpg = 29 or higher Fuel economy (mpg) COMBI CITY HWY Chevrolet Cruze Turbo Diesel Mazda3 i Grand Touring hatchback Toyota Corolla LE Plus Ford Focus SE SFE Volkswagen Jetta SE (1.8T) Nissan Sentra SV Honda Civic EX Hyundai Elantra GLS Dodge Dart Rallye FueleconomyofHEVissuperior,however,

37 Examination of fuel economy Fuel cost / year 5000 assuming 19,000km /year gasoline price; 3.8$/gallon Mid size cars =250$/year Compact cars =237$/year Mid size conventional 1150 Mid size HEV mpg AveragedrivecannotpayofthepriceincreasebyHEVby superiorfueleconomy

38 Summary 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. 38

39 Thank you for your attention!

40 Conclusion 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.

41 Additional message 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.

42 SKYACTIV engines: Next step Further thermal efficiency improvement 2000rpm/20kPa 8 SI λ= % 48% 48% Excessairratioλ 空気過剰率 λ SIlean-burnisnotfeasibleatλ>2 CAI λ=2.5 44% 46% % 44% 42% Compressionratio 圧縮比 ε NOx=0 λ>2.2 The 2 nd step engine targets higher CR & leaner CAI. 42

43 Goal of SKYACTIV engines Comparison of thermal efficiency improvement 60 Engine Eficiency [%] MotorandBatteryEfficiency 1 st step 2 nd step 3 rd step [%] [km/h] VehicleSpeed Time [sec] 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

44 Goal of SKYACTIV engines Targeted CO2 reduction level by ICE improvement Well-to-Wheel CO2 g-co2/km Former model SKYACTIV-G1 SKYACTIV-G2 SKYACTIV-G3 ICE HEV 1 st step 2 nd step 3 rd step Case study Mazda2 JC08 (including vehicle improvement) EV Mazda2 EV (1180kg) 100Wh/km 0% Non thermal power generation 37% 2010 actual 0 Calculated based on Electric generation life cycle by Central Research Institute of Electric Power Industry(2010) Aiming at CO2 level of EVs by ICE improvement 44

45 Goal of SKYACTIV engines Targeted CO2 reduction level by ICE improvement US CombiC-Segment including vehicle improvement CO2/Gasoline 2.32kg/L ICE HEV EV 150 SKYACTIV-G1 1 st step Well-to-wheel CO2 - g/km Well-to-wheel CO2 - g/km SKYACTIV-G2 SKYACTIV-G3 EPA CARB 0 US average level of CO2 is achievable.