When new emission legislation is introduced in the passed there has been a political ambition to promote early introduction of the new technology. For Euro V there was an exception for “Euro V incentive” engines not to meet the full demand specification concerning diagnostics and other supposedly peripheral demands in the legislation.
Now, when looking ahead towards the Euro VI legislation for buses again I hear about the demand for early introduction of the new legislation. What will the effect be on the environment?
When comparing the environmental impact of Euro V and Euro VI we can use the European directive for Public Procurement of environmentally friendly road transports where the cost for the society is monetised. (Read about the procurement here)
The contributions to e.g. health related cost from energy use, carbon dioxide, NOx, particulate matter and hydrocarbons are added to the total cost for society.
When going from Euro II to Euro III it was found that the fuel consumption increased when the NOx was brought down. For Euro VI with out knowing the details I have estimated the fuel consumption increase to 3%. Carbon dioxide will decrease with the corresponding number. For the emissions of NOx I have uses the change from 2 to 0.4 g/kWh for NOx and from 0.02 to 0.01 g/kWh for particulate mater. For the hybrid however we have found that the emissions of NOx are reduced by 50% when compared to the standard diesel bus and the hybrid can be equipped with an particulate filter reducing the particulate matter by 90%.
In the graph below we find that the Euro VI City Bus will decrease the total environmental impact by about 5% when compared to the Euro V bus, while the corresponding hybrid bus will decrease the environmental impact by about 33%.
I therefore say that for the environment, the best Euro VI incentive is a Volvo 7700 Euro V Hybrid Bus!
Volvo Bus Corporation introduced the D13 engine in the 9700 Coach, in 2009, to meet the Euro V emission legislation. In addition we introduced a new version of the I-Shift gear box. Before the launch we confirmed 3% fuel consumption improvement on our test coaches, relative to the corresponding coach with an Euro IV certified 12 litre engine. Still, it is always exciting to see the data from real traffic. We now have the results from the first six months and we are able to confirm the fuel consumption improvement.
In the average statistics for 9700 in Europe, in the picture below, I have selected data from the 9700 in the 6×2 version. The three axle, 6×2, coaches are mostly between 13.3 and 14.5 metre. The taller coaches are chosen for the high passenger capacity. A typical 12 metre coach takes just about 50 passengers while the 14.5 metre coach takes 64. It is an increase by almost 30% while the fuel consumption increase by 10% for the taller coach. It is thus a good deal for the environment to choose a large coach, provided that the increased capacity is used.
The simultaneous improvement of emissions and fuel consumption is a rare combination. When you ad the increased power of the D13 engine to the picture, the combination is unique.
Let me also share some experiences from the B12B statistics from different regions. Again, the data is exclusively from 9700 with three axles, 6×2. You can see the positive influence of smooth but slow traffic flow in Denmark, the cost for the hot climate air conditioning and hilly roads in Spain, While Sweden and Germany have similar traffic fuel consumption when the same average speed is compared. The data is gathered from a large number of buses in daily operation in Europe.
In 2010 the Challenge Bibendum event took place in Rio de Janeiro, Brazil. In the race, new vehicles challenge the state of the technology in different race classes. Now a days, Challenge Bibendum has strong environmental focus including disciplines such as Noise, Hazardous emissions, carbon dioxide and fuel efficiency.
Three Volvo buses and coaches participated:
1) B9SALF a bi-articulated bus with very high passenger capacity, the only full low floor bus in Latin America, with high preference for BRT routes.
2) B7RLE a low entry bus with global sales known for its low fuel consumption, in the race a prototype body was used.
3) B9R a coach with a high efficiency 9 litre engine equipped with the I-Shift automatic manual gear box.
The bi-articulated performed very well and we know that it has superior performance when it comes to fuel efficiency per passenger. It was alone in its class and was hence not listed for any prices.
Both the B9R and the B7RLE were rewarded in the race. Most impressive was the fuel consumption for B7RLE of 13.7 litre per 100 km, and yes it’s a twelve meter bus on a standard Volvo chassis!
Volvo Bus Corporation has a joint venture with the Chinese automotive manufacturer, SAIC, since soon 10 years. Sunwin Bus corporation is one of the leading bus manufacturers in China. It is impossible to miss the green and white Sunwin and Volvo buses in Shanghai. They have become synonymous with efficient public transports in one of the most rapidly growing cities in the world.
Also at the World Expo the modern buses characterise the picture and many of the travellers, that have visited the expo are enthusiastic about the fully electric buses.
There are several different version of fully electrical buses. Some are equipped with super capacitors that can charge rapidly at the bus stops. A connector in the roof connects to the stationary electrical installation when the bus stops to let the passenger on to the bus.
Another electrical bus is equipped with batteries that can be run for some three hour before they are exchanged to a freshly charged battery pack at one of the end stations.
I got the pictures from Björn Brännberg at the event organisation.