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Analysis of CO2 Emissions and Other Characteristics of New German Passenger Cars Efthimios Zervas* Department of EnVironmental Engineering, Democritus UniVersity of Thrace, Vas. Sofias 12, Xanti 67100, Greece ReceiVed August 29, 2008. ReVised Manuscript ReceiVed October 31, 2008
This work analyses the CO2 emissions and the other main characteristics (displacement, maximum and specific power, segment distribution, and weight) and their trends of diesel and gasoline new passenger cars (PCs) in Germany. This analysis concerns average values and distribution of these characteristics during the last few years. The analysis of each firm is also performed. The scope of this analysis is to better understand the reasons and the difficulties for the quite moderate exhaust CO2 decrease during last few years. The results show that average displacement remains quite constant during the years studied. However, there is a continues run to increase both power and specific power of new engines. The average weight of new diesel and gasoline PCs also constantly increases. For both diesel and gasoline PCs, there is a general tendency to increase the two extremes: small and also very big cars. CO2 emissions on the New European Driving Cycle (NEDC) decrease 14.6% in the case of diesel and 16.6% the case of gasoline PCs during 1995-2003. Volkswagen (VW) is the leading firm for both diesel and gasoline PC sales, followed by Mercedes. Bayerische Motoren Werke (BMW), Mercedes, and Audi are generally the leaders in terms of displacement, power, and weight in both diesel and gasoline PC, and generally, they also have the higher average CO2 emissions.
1. Introduction Atmospheric CO2 is one of the main contributors to climatic changes. CO2 is mainly anthropogenic; its principal source is energy production from the combustion of fossil fuels. Road transport is one of the major sources of CO2 because it counts for about one-fifth of the total CO2 emissions in European Union (EU), while the contribution of passenger cars (PCs) is about 12%.1 There are several parameters that influence CO2 emissions of a PC. The first is fuel used: PCs using gasoline or diesel or other fuels (natural gas, propane, etc.) have different CO2 emissions.2 Vehicle weight influences CO2 emissions because increased weight needs more fuel for the same driving distance.3-8 As a consequence, vehicle segment influences CO2 emissions through the different average weight of each segment.9 Engine displacement also increases CO2 emissions, because more fuel is necessary to fill the cylinder.2,3,10 Engine frictions and vehicle aerodynamics also increase CO2 emissions through the increased necessary power.2 Engine design and combustion are also * To whom correspondence should be addressed. Telephone: +30-2451079392. E-mail:
[email protected]. (1) Eurostat. europa.eu.int/comm/eurostat/ (accessed on Jan 2008). (2) Stead, D. Transp. Policy 1999, 6, 247–258. (3) Van den Brink, R. M. M.; Van Wee, B. Transp. Res., Part D 2001, 6, 75–93. (4) Sullivan, J. L.; Baker, R. E.; Boyer, B. A.; Hammerle, R. H.; Kenney, T. E.; Muniz, L.; Wallington, T. J. EnViron. Sci. Technol. 2004, 38, 3217– 3223. (5) Zervas, E.; Bikas, G. Energy Fuels 2005, 19 (5), 1919–1926. (6) Zervas, E.; Poulopoulos, S.; Philippopoulos, C. Energy 2006, 31, 2579–2589. (7) Zervas, E.; Lazarou, Ch. Int. J. Energy Res. 2007, 31, 192–203. (8) Zervas, E.; Lazarou, Ch. Influence of European passenger cars weight to exhaust CO2 emissions. Energy Policy 2008, 36, 248–257. (9) Zervas, E. SAE Tech. Pap. 2007-01-1947, 2007. (10) Sorrell, S. Energy Policy 1992, 20, 766–780.
important parameters because they contribute to output power, exhaust emissions, and fuel consumption.2 Emission control and after-treatment devices generally increase CO2 emissions.2,10 Vehicle speed and driving conditions also influence these emissions.2 Of course, the above parameters influence CO2 emissions per kilometer, because total CO2 emissions depend upon the annual mileage of each vehicle. Each country has its own particular market of PCs. For example, Swedish PCs are generally heavier than the EU average.7,9 In different EU countries, segment distribution is not the same.9 The analysis of the PC market of a particular country can give very useful information about the CO2 emissions control. A previous study11 compares the CO2 emissions from passenger transport in Germany and other eight Organization for Economic Cooperation and Development (OECD) countries from 1973 to 1992; however, the PC market is not studied. Sorrel10 studies the U.K. PC market from 1983 to 1990 and reports the CO2 emissions change during these years. This work studies the German market of PCs, which is the biggest in the EU. Several parameters, such as new PC registrations, type of fuel used, engine displacement, maximum power, maximum specific power, segment distribution, vehicle weight, and CO2 emissions on the New European Driving Cycle (NEDC), are analyzed. This analysis concerns the years 1995-2003 and is focused on the average values of each year and also in their distribution. The second part is focused on the average values on each year of the main firms presented on the German market. 2. Data and Methodology Used The data of all new PCs sold in Germany during 1995-2003 are used here. The statistical data are a compilation of data presented (11) Scholl, L.; Schipper, L.; Kiang, N. Energy Policy 1996, 24, 17– 30.
10.1021/ef800723k CCC: $40.75 2009 American Chemical Society Published on Web 12/15/2008
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in several Internet sites, such as Eurostat,1 World Resources Institute (WRI),12 International Road Federation (IRF),13 Association of European Automobile Manufactures (ACEA),14 German Federal Motoring Authority (KBA),15 and Committee of French Automobile Manufactures (CCFA)16 and verified from personal communications with several representatives of automotive constructors. Because of the lack of data for the new countries of the EU, the data of the previous 15 countries (EU15) were used here where a comparison is performed. The CO2 emissions of the PCs certified in Germany are obtained according to the official European certification procedure on the NEDC. As mentioned earlier, CO2 emissions depend upon several parameters, such as driving profiles, annual mileage, etc., and as a consequence, real-world emissions are different. However, because the only official base is CO2 emissions on the NEDC, these data were used here. Another two important factors for the total CO2 emissions are the annual mileage of each vehicle and the vehicle occupancy. These two parameters are not studied here, because the target of this work is to compare the models sold in the German PC market and not the total CO2 emissions from the transport sector.
3. Results and Discussion 3.1. General Presentation of the German Market of PCs. Germany had a population of 83.5 million inhabitants in 2003,1 which corresponded to 21.6% of the EU15 population (EU of 15 country members) and 1.3% of the global earth population. The German population remains quite stable, because the increase from 1995 to 2003 was only 1.2%. Germany is the most significant PC market in EU from several points of view. First of all, Germany has a PC fleet of more than 46 million vehicles in circulation in 2003,1,12,13 an increase of 12% since 1995. This value corresponds to 23.6% of the total EU15 PC fleet in this year and to 559 PC/1000 inhabitants, against 504 for the rest of the EU15 average. Germany is also a significant market for new PCs, because more than 3 million new PCs were sold in 2003,1,14,16 which corresponds to 23.3% of the EU15 new registrations and to 36.4 new PC registrations/1000 inhabitants against 33.9 for the EU15 average. Total registrations of new PCs in Germany increased from 1995 to 1999. After this year, a decrease is observed in the year 2000, and since that year, the total registrations remained relatively constant (Figure 1), indicating a saturation of the market. However, the German market remains dynamic because it constantly shifts to diesel PC because the percentage of new diesel PC increased from about 13% in 1995 to more than 38% in 2003. Moreover, the segment distribution and the firms percentage significantly changed during these years. 3.2. Correlations between the PC Parameters. The engine/ vehicle parameters studied here are linked between them. Exhaust CO2 is also related to engine displacement, engine maximum power, and engine specific power. CO2 emissions increase with vehicle weight and engine displacement.2,4-6,10 These correlations are described in another work.17 3.3. Displacement. In Germany, the average displacement of new diesel and gasoline engines in 2003 was 2078 and 1707 (12) World Resources Institute. earthtrends.wri.org (accessed Jan 2008). (13) International Road Federation. www.irfnet.org (accessed Jan 2008). (14) Association of European Automobile Manufactures (ACEA). www. acea.be (accessed Jan 2008). (15) German Federal Motoring Authority (KBA). www.kba.de (accessed Jan 2008). (16) Committee of French Automobile Manufactures (CCFA). www. ccfa.fr (accessed Jan 2008). (17) Zervas, E.; Diamandopoulos, E. Waste Management, Water Pollution, Air Pollution, Indoor Climate (WWAI’08), Corfu, Greece, Oct 2426, 2008.
Figure 1. Number and percentage of registrations of new PCs: total registrations and diesel and gasoline PCs.
Figure 2. Average values of displacement (cm3), weight (kg), power (kW), and specific power (kW/L) for the gasoline (red) and diesel (blue) vehicles during 1995-2003.
cm3, respectively. The average displacement remains quite constant during 1995-2003 (Figure 2). In a previous study, the displacement of Dutch new PCs increased about 13% from 1985 to 1995.3 However, in the German market, significant changes are observed for both diesel and gasoline engines. Figure 3 shows that the major part of new diesel vehicles is composed of engines within 1800-1900 cm3, while the displacement of new gasoline engines is more widely dispersed. The number of new diesel engines of almost all displacements increases as a consequence of the increase of the registrations of new PCs. The upper bars of this figure show the corresponding percentages and that a significant increase of two ranges of displacement occurs: the percentage of small engines (2000 cm3. The first one is a result of the general shift to smaller engines, and the second one results from the sales of big and luxury cars equipped with these engines, indicating that their buyers are not attracted to the general shift to diesel vehicles. Concerning the corresponding percentages, there is a small increase of these two ranges, while there is not a clear tendency of the others. 3.4. Engine Maximum and Specific Power. Figure 2 shows that there is a continuous run to increase both power and specific power of new engines. In 2003, the average power was 93 and 84 kW for new diesel and gasoline engines, respectively, while the corresponding values of specific power were 44 and 48 kW/ L. The power of diesel and gasoline engines showed a spectacular increase of 35 and 20% in only 8 years (32.75 and 18.8% for the specific power). In another study,3 the increase of 13% is observed in the case of power of Dutch PC from 1980-1997. Looking at the maximum power offered in the market, the most powerful diesel PC had 125 kW in 1995 and 230 kW in 2003 (increase of 82%), while the corresponding values for gasoline are 316 and 482 kW, respectively (increase of 52%).
Figure 4 shows that this increase is not the same for all types of vehicles. The number of diesel vehicles with a maximum power less than 70 kW remains quite stable or decreases. The number of new registrations of more powerful vehicles increases, with the most important increase observed with the vehicles with a maximum power > 110 kW. It is obvious that the percentage of less powerful vehicles decreases, while the percentage of more powerful engines generally increases. The results of gasoline engines are quite different. The registrations (and the corresponding percentages) of PCs with engines less than 40 kW have decreased sharply since 1995. The registrations of middle power vehicles (50-100 kW) decrease; however, their percentage remains quite constant. However, the sales of engines more than 100 kW remain quite constant, and their corresponding percentage increases. This figure indicates that gasoline registrations are more and more concentrated to the very “weak” and “very powerful” engines. Figure 5 shows the changes of the specific power. It is very clear that the number of new vehicles with a specific power less than 35 kW/L shows a significant decrease (the engines with specific power less than 25 kW/L almost disappear in 2003), while the vehicles with specific power more than 35 kW/L show a sharp increase: The sales of the vehicles in the range of 45-50 and 50-55 kW/L are multiplied by 77 and 31 times between 1998 and 2003, while their sales were null before 1998. The corresponding percentages show the same general tendencies. The results of gasoline engines are less clear. As in the case of diesel engines, the sales of low-power gasoline engines (less
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Figure 5. Number of new vehicles (lower bars) and percentage (upper bars) that have a certain specific power. Diesel (left bars) and gasoline (right bars) new PCs.
Figure 6. Number of new vehicles (lower bars) and percentage (upper bars) that are within a certain vehicle weight. Diesel (left bars) and gasoline (right bars) new PCs.
than 35 kW/L) sharply decrease and the same is observed in the case of medium-power engines (40-45 kW/L). The registrations of the very powerful engines, more than 55 kW/ L, increase, while the other ranges remain constant. Taking into account the decrease of the total sales of gasoline vehicles, once again, the percentages of the less powerful engines generally decrease, while those of the powerful engines increase. 3.5. Weight. Figure 2 shows that the average weight of new diesel and gasoline PCs constantly increases during 1995-2003. This is also observed in the case of the Dutch PC market from 1985 to 1997.3 The average weight of new diesel PCs passed from 1336.9 kg in 2003 to 1451.6 kg in 2003 (an increase of 8.6%), while that of the gasoline ones passed from 1139.7 to 1197.2 kg (an increase of 5.6%) during the same period. This results from the combination of the shift to heavier PCs and the increase of each PC weight, as already reported by Van den Brink and Van Wee3 for the Dutch PC market. The major part of diesel vehicles (35-45%) are found between 1800-1900 kg, while the weight distribution is wider in the case of gasoline vehicles. Figure 6 shows that the weight increase is not the same for all PCs. The number of diesel PCs increases for all weight ranges (as the total registrations increase), except in the ranges of 1700-1800 and 2200-2500 kg, obviously because car manufacturers propose less models of these weight ranges. However, the upper left panel of Figure 6 shows that the relative percentages of three ranges show a significant increase: 4m50; 4 × 4-1, 4 × 4 4m50.
Figure 8. Average values of CO2 emissions on the ECE, EUDC, and NEDC (g/km) for the gasoline (red) and diesel (blue) vehicles during 1995-2003.
The above results show that, for both diesel and gasoline PCs, there is a tendency to increase the two extremes: smaller and also bigger cars, as already found in the analysis concerning the previous parameters. The increase of small cars has a significant benefit on CO2 emissions; however, the increase of heavy cars has the opposite effect. 3.7. CO2 Emissions. Figure 8 shows the average CO2 emissions of the new PCs on the NEDC and the urban (ECE) and extra-urban (UEDC) part of the cycle. It is clearly shown that the CO2 emissions on the NEDC decrease for both gasoline and diesel vehicles from 193 to 164.7 g/km in the case of diesel PC (decrease of 14.6%) and from 214.1 to 178.6 g/km in the case of gasoline PC (decrease of 16.6%) from 1995 to 2003. However, this figure shows that this decrease comes mainly from the UEDC, where the corresponding decreases are 18.5 and 15%. The emissions of the ECE sharply increase for both diesel and gasoline PCs from 1995 to 1998, and then they decrease very slightly or even have an increased tendency during last few years in the case of diesel PCs. In total, from 1995 to 2003, average ECE CO2 emissions increase 21.2% for diesel and 28.3% for gasoline PCs. This means that, even if NEDC CO2 emissions decrease, there is no guarantee that real-world total CO2 emissions decrease, even if NEDC CO2 emissions decrease.
The total decrease depends upon the ratio between the total urban and extra-urban mileage of each vehicle. Figure 9 shows the detailed changes of CO2 emissions. In the case of diesel PCs, the vehicles with CO2 emissions up to 190 g/km increase. Other significant changes concern the sales of the 200-250 g/km range, which decrease, and the >250 g/km range, which increase. Examining the corresponding percentage closer, the upper left bars of Figure 9 shows that there is a significant increase of the very low CO2 emissions (200 g/km) decreases significantly. The total new registrations of almost all CO2 ranges decrease in the case of the gasoline PCs as a consequence of the total registrations decrease, except in the case of the very low CO2 emitting vehicles 170 g/km), while an increase is observed in the case of the PCs with CO2 emissions lower than 170 g/km. These results show that the decrease of CO2 emissions come from the significant decrease of new registrations of the very high CO2 vehicles and also the shift of all vehicles to lower CO2 emissions. However, the small percentage of the very high CO2-emitting vehicles does not always follow the same tendencies. 3.8. Analysis of Each Firm. Figure 10 shows the registrations of new PCs of each firm. Only the firms that occupy at least 1% of the new PCs market each year are shown here. This figure shows that the sales of all firms increase in the case of diesel PC and decrease in the case of gasoline PC because of the corresponding increase and decrease of total sales. Volkswagen (VW) is the leading firm for both diesel and gasoline PC, followed by Mercedes. Audi and Ford are the third firms in the case of diesel and gasoline PC, respectively. This figure shows that there is a quite clear classification in the case of diesel PC in terms of sales and percentage and that there are quite significant differences between the sales and percentages of each firm. The VW percentage shows a quite significant decrease, and the percentage of Bayerische Motoren Werke (BMW) shows a significant increase, while the percentages of Mercedes and Renault increase slightly. The percentage of the other firms does not show significant changes. The situation of the gasoline PC market is quite different. The sales of all firms decrease, as a consequence of the total sales decrease; however, the sales of Toyota remain constant,
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Figure 9. Number of new vehicles (lower bars) and percentage (upper bars) that emit a certain quantity of CO2. Diesel (left bars) and gasoline (right bars) new PCs during 1995-2003.
Figure 10. Number of new PCs (lower curves) and percentage (upper curves) of each firm. Diesel (left curves) and gasoline (right curves) new PCs during 1995-2003.
while those of Mercedes saw a significant increase from 1995 to 1998. Expect VW, who is the leader, the sales and percentages of the other firms are very close to each other. Most of these percentages are quite constant, except those of Mercedes and Toyota, which constantly increase, while VW and Fiat show a slight decrease. The average displacement of each firm is shown in Figure 11. In the case of diesel PC, the two leaders are BMW (with increased tendency) and Mercedes (with significant fluctuations). These two firms are specialized in big engines because they have in 2003 an average displacement of about 2500 and 2350 cm3, respectively. Expect the average displacement of Audi, which had some fluctuations, the average displacement of all other firms is around 1900-2000 cm3. The situation of gasoline PC is similar but with more significant differences. BMW, Mercedes, and Audi are again the three leaders, with average displacement of around 2100-2300 cm3, with an increased tendency. It is remarkable that, for these three firms, there is very little difference between the average displacement of diesel and gasoline PC. The average displacement of all other firms
is quite lower and generally between 1400 and 1600 cm3. Fiat is focused on vehicles of very small engines between 1200 and 1300 cm3. The maximum power of almost all firms sharply increases during 1995-2003 for both diesel and gasoline PC. Generally, the maximum power increases with displacement. Because the engines of BMW, Mercedes, and Audi are the bigger ones, they also have the highest maximum power (Figure 12). BMW is the incontestable leader of diesel PC, with more than 130 kW in 2003, followed by Mercedes and Audi (100-110 kW in 2003). The values of these three firms are all much higher than the average value (93 kW in 2003). All other firms are found together, with 70-80 kW in 2003, much lower than the average value. Renault, Mercedes, and BMW showed the higher increases between 1995 and 2003: 39-40% each, while the lower ones are observed in the case of Opel (21%) and Peugeot (26%). BMW, Mercedes, and Audi are also the three leaders in the case of gasoline PC, with a maximum power of 115-130 kW in 2003. Toyota is fourth with about 85 kW, followed by all
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Figure 11. Average displacement of new PCs of each firm. Diesel (left curves) and gasoline (right curves) new PCs during 1995-2003.
Figure 12. Average maximum power of new PCs of each firm. Diesel (left curves) and gasoline (right curves) new PCs during 1995-2003.
other firms, which are found between 60 and 70 kW, except Fiat, which has the lower values with 44 kW. As in the case of diesel engines, the three leaders are found much higher than the average value, while the other firms are quite lower. Renault shows the highest increase during 1995-2003 (30%), followed by Audi and BMW (18% each), while Mercedes showed the lowest value of 7%. The technological improvements of each firm are better visualized studying the specific power (Figure 14). When Figure 13 is compared to Figure 14, some significant differences between maximum power and maximum specific power can be observed. In the case of diesel PC, BMW is again the leader (51 kW in 2003); however, it is now closer to the second one, Audi (48 kW). Mercedes remains the third firm (45.7 kW); however, it is almost reached by Renault (45.2 kW), VW (43.4 kW), and Ford (43.4 kW), who are far behind in the case of maximum power. This is because Mercedes obtains high maximum power mainly by using big engines, apparently with less technological improvements than BMW. However, Mercedes was at the same level as Opel, Peugeot, and VW in 1995, and Renault had lower values of specific power. Mercedes and Renault are found in the third and fourth position in 2003, while
the increase of the other firms was moderate, indicating that Mercedes and Renault used more technological improvements that the other firms during these years. These two firms showed an increase of maximum specific power of 51 and 42%, respectively, compared to 32-33% for Audi and VW, 29% for Ford, and 26% for BMW. The differences between maximum power and maximum specific power are also significant in the case of gasoline PCs. Audi, Mercedes, and BMW are now together in the first range (54.7, 54.3, and 54.1 kW/L in 2003), followed very closely by Toyota (51.5 kW/L). Renault is next (47.5 kW/L), while the other firms ranged from 40 to 44 kW/L. The highest increase is also observed in the case of Renault (37%), following by VW (20%) and Audi (14%), while the other firms ranged from 6 to 12%. This figure clearly shows that BMW, Mercedes, Audi, and Toyota have the best technology, while Renault and VW performed the best improvement. Figure 14 shows that, in the case of both diesel and gasoline PC, BMW, Mercedes, and Audi offer the heavier cars. The average weight of these three car manufacturers is higher than the average value, while that of the other firms is lower. Engine
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Figure 13. Average maximum specific power of new PCs of each firm. Diesel (left curves) and gasoline (right curves) new PCs during 1995-2003.
Figure 14. Average weight of new PCs of each firm. Diesel (left curves) and gasoline (right curves) new PCs during 1995-2003.
displacement is generally linked with engine weight, because heavier cars are generally equipped with bigger engines. In the case of diesel PC, VW showed the higher increase of its average weight: 17.4% from 1995 to 2003, followed by Peugeot (16.7%), BMW (12.5%), Ford (10%), and Renault (9.7%), while the other firms showed a small increase, less than 5.0%. In the case of gasoline PC, Renault, Fiat, and VW showed the higher increase: 8.4, 7.1, and 6.8%, respectively, while the other firms showed a very small increase, less than 3%. The average weight of Audi and Ford remained practically constant, while Mercedes is the only firm that showed a decrease (-4%). It must be noticed that, during the last 2-4 years, VW, Ford, and BMW showed a decrease. Figure 15 shows the average CO2 emissions of each firm, where it is clearly shown that almost all firms made significant efforts to decrease their emissions. Once more, BMW, Mercedes, and Audi are the firms with the higher emissions for both diesel and gasoline PC and are found in higher positions than the average value, while the other firms have lower values. Globally, the diesel average CO2 emissions of each firm are from 147 to 181 g/km. Renault showed the higher decrease of its average CO2 emissions: 27% from 1995 to 2003, followed
by Peugeot (23.2%), Mercedes (22.7%), and Ford (22.1%), while Audi and VW have the lowest decreases (5 and 1.7%, respectively). It must be noticed that, in most cases, the most significant decrease is observed until 1999-2000. After this year, the average CO2 emissions of each firm show very little changes and, in some cases (BMW, VW, Mercedes, and Ford), even an increase is observed, indicating that most of the car manufacturers face difficulties decreasing the CO2 emissions more. The general allure of the average CO2 emissions of the gasoline PC is like that of the previous parameters, with three leaders, Mercedes, BMW, and VW, while the other firms are quite lower. Mercedes is now the leader, with 215 g/km, and BMW and Audi are a little lower (204 and 200 g/km, respectively). All other firms are found between 151 and 172 g/km, with Fiat in the last position. The most significant decrease is observed in the case of Renault (25.1%), Ford (21%), and BMW (19.9%), while most of other the firms are found between 14 and 17%. Generally, as in the case of diesel PC, this decrease is generally observed until 1999-2000 and the emissions remain quite constant or show a small decrease since that year (or even a small increase as in the case of Audi, VW, and Fiat). This
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Figure 15. Average CO2 emissions on the NEDC of new PCs of each firm. Diesel (left curves) and gasoline (right curves) new PCs during 1995-2003.
last result shows that the classical methods for the CO2 decrease (mainly based on engine tuning) reached their limits, and other ways, such as weight or power limitations or shift to small engines, must be searched in the future. 4. Conclusions This work analyses the tendencies of the Germany PC market, which is the most significant in EU15. The first conclusion is that the German market constantly shifts to diesel PC: from 13% in 1995 to more than 38% in 2003. The German market has PCs with quite big engines because their average displacement was 2078 and 1707 cm3 for the gasoline and diesel PCs, respectively. These values remain quite constant during 1995-2003. During those years, both power and specific power of new PCs show a very significant increase of about 35 and 20% for the new diesel and gasoline engines. This is due to the amelioration of the combustion efficiency, which is very encouraging for the CO2 emissions control. However, the average weight of new diesel and gasoline PCs constantly increases during those years, which is discouraging for CO2 emissions control because the increased vehicle weight needs more energy to be moved. Concerning the weight of new
PCs, there is a general tendency to increase the two extremes: small and also very big cars, for both diesel and gasoline PCs. From 1995 to 2003, CO2 emissions on the NEDC show a significant decrease of about 15 and 17% for the diesel and gasoline new PCs, respectively. However, this decrease mainly comes from the UEDC, while the emissions of the ECE sharply increase for both diesel and gasoline PCs from 1995 to 1998 before a slight decrease. This means that there is no guarantee that real-world total CO2 emissions decrease, even if NEDC CO2 emissions decrease, because the total decrease depends upon the ratio between the total urban and extra-urban mileage of each vehicle. In the future, other ways, such as weight or power limitations or shift to small engines, must be searched to decrease CO2 emissions. There are significant differences between the characteristics of the firms presented in the German market, with three firms: BMW, Mercedes, and Audi, having quite higher average values of displacement, power, weight, and CO2 emissions for both diesel and gasoline PCs, indicating that the effort to decrease CO2 emissions is not the same for each firm. EF800723K
