Here is an interesting report from BMW on diesels in North America. Lots of interesting facts that some of us might have not known.
The introduction of modern clean diesels to the U.S. market has been pioneered by manufacturers from Europe, where diesel vehicles have a very high degree of acceptance for their performance, efficiency and lower CO2 emissions.
The automaker with the longest history is Mercedes-Benz (M-B) introducing diesel vehicles in its line-up beginning in 1968 with the 200D and 220D. The four-cylinder 200 D cranked out all of 55 hp, giving the car a 0-to-62-mph time of 28 seconds and a top speed of 81 mph.
Sales of passenger cars powered by diesels grew rapidly, peaking in 1981 at 520,788. Some 60 percent of those diesel cars were built by General Motors. That was 10 percent of GM sales that year. For other makers, diesels were a bigger factor. They accounted for almost 85 percent of Peugeot sales in the United States, 78 percent of Mercedes-Benz sales, 58 percent of Isuzu sales and almost half of Volkswagen sales. Diesel passenger cars were also sold by Audi, Volvo and Datsun in 1981.
Shortly after this, significant problems began to appear in GM diesel-powered vehicles. Blocks cracked and crankshafts wore prematurely. Critics complained that it was just a converted gasoline engine and clubs of disgruntled owners sprang up and lawsuits were filed. Tougher emission standards caused problems for all diesel makers. Hammering the final nail in the diesel’s coffin, the price of gasoline began to decline. So did diesel sales. GM, which had been so bullish on diesels, ended production in 1985.
BMW brought its first diesel to the U.S., the 524td in 1985. It was the fastest, most powerful diesel vehicle of its time. However, around the mid ‘80s, consumers lost interest in diesels and became less concerned about fuel efficiency due to receding fuel prices in the U.S. As a result, the 524td was short-lived and ended its cycle with the 1986 model year.
In the intervening years, BMW’s engine development specialists enhanced a wide range of innovations, ensuring their alignment with series production standards, increasing power and performance, reducing fuel consumption and emissions in the process. In 1987, for example, BMW introduced Digital Diesel Electronics followed three years later by BMW’s first diesel engine with an oxidation catalyst.
Right from the start BMW’s engine development specialists recognized the potential of diesel in enhancing efficiency. They focused on the unique performance characteristics offered by diesel, providing an entirely new concept of The Ultimate Driving Machine. Above all, they used the performance of the diesel engine to develop superior torque from low engine speeds.
As a result, the BMW diesel was soon able to offer its unique sporting character – in everyday driving situations, as well as on the race track. A BMW was the first diesel-powered race car to win a 24-hour endurance race when a BMW 320d won the 24 Hours of Nürburgring in 1998.
In the same year BMW presented its first diesel engine with direct fuel injection ensuring even greater spontaneity in the development of power. In the process, the precise dosage of fuel helped to reduce fuel consumption and optimize combustion in the interest of even greater smoothness and refinement. Ultimately, given these qualities, the BMW diesel was appropriately prepared for the luxury performance class, with the first V8 diesel engine featuring direct fuel injection, which made its debut in the BMW 7 Series luxury sedan in 1999.
Milestones in progress: Common-rail direct fuel injection, Sequential Twin Turbo Technology, maintenance-free diesel particulates filter, BluePerformance.
In the years that followed, BMW made significant – perhaps revolutionary – progress in the areas of injection technology and diesel turbocharging. As early as 2001, the second generation of common-rail fuel injection pumped fuel into the combustion chambers at a pressure of up to 1,600 bar, or over 23,000 psi. In 2004, the BMW 535d became the first car to feature an inline-six diesel with Sequential Twin Turbo Technology.
BMW also introduced the second generation of the diesel particulate filter now featured as standard equipment in all its diesel models. The exhaust gas-cleaning unit is positioned directly on the exhaust manifold itself in order to ensure optimum efficiency very quickly and smoothly. The particulate filter does not require any maintenance and regenerates itself by incinerating the diesel particles. This filtering function is performed at all engine speeds and under all loads, without any reduction of engine power or increase in fuel consumption.
BMW’s current range includes a number four-cylinder and six-cylinder diesel engines. Both the six- and four-cylinder engines have aluminium crankcases helping to significantly reduce the weight of these engines. A traditional handicap of the diesel engine, which adds weight due to the use of a cast iron crankcase (a much heavier material than aluminium), has nearly been phased out completely. The reduction of weight enhances the car’s agility and, as a result, the sporting character of BMW’s diesel models.
Comparing the first six-cylinder BMW diesels from 1983 with the most powerful diesel engines of today, one can easily appreciate the progress made. Consider the following facts and figures:
Maximum output of the inline-six engine is up 135 percent, maximum torque is up an even more impressive 170 percent. And despite this immense increase in power and muscle, average fuel consumption of the 3.0-liter engine featuring Sequential Twin Turbo Technology is 20 percent lower than diesel engines of 1983. At the same time, exhaust emissions have been reduced dramatically, thanks to several new technologies. For example, a BMW diesel in the 2008 model year generates only 1 percent of the particulate emissions originally contained in the exhaust gas of a 1983 diesel model.
Currently, in the U.S., hybrids are widely praised for their efficiency and environmental friendliness, modern clean diesel technology has struggled to gain recognition as a viable alternative even though media reports about diesel vehicles have been mostly positive, citing advantages in performance, efficiency, range and of course, lower GHG emissions and reduced use of fossil fuels.
While acceptance with the general public has lagged behind critical media acceptance, once again perceptions are beginning to shift as evidenced by growing sales of the VW Jetta and BMW X5 xDrive35d over the last two model years.
BMW Group Diesel in the U.S.
Technology and Market situation
In 2009, the BMW Group presented more proof of its EfficientDynamics engineering philosophy with the introduction of two BMW Advanced Diesel models for the U.S. The 335d and the X5 xDrive35d models feature a 50 state emission compliant version of BMW’s award winning sequential-turbo 3.0 liter diesel engine. This is the first performance-oriented Advanced Diesel engine in BMW’s North American model line and is the basis for the most fuel efficient internal-combustion vehicle BMW has ever sold in the United States.
The sequential-turbo 3.0 liter diesel engine employs both a very small and a larger turbocharger combined with an innovative intake system, enabling the engine to develop 265 hp. Even more impressive are the torque characteristics. Fully 80% of the torque is available from 1100 rpm to 4200 rpm. Peak torque is 425 lbs-ft at 1750 rpm – almost as much as BMW’s 6.0 liter V12. The resulting performance is what an enthusiast would expect from a BMW. The 335d is capable of sprinting from 0 – 60 mph in six seconds flat, and the X5 xDrive35d will do it in 6.9 seconds. No other Diesels in the U.S. perform like these BMW Advanced Diesel models.
Coupled with this performance potential is impressive fuel economy. The EPA mileage estimates for the 335d are 23 City and 36 Highway – the best figures ever achieved by a road going BMW in the U.S. The X5 xDrive35d is rated at 19 mpg City and 26 mpg Highway. The X5 xDrive35d offers the convenience of travelling more than 580 miles between fill-ups, while the 335d can go approximately 560 miles between fuel stops. While the 335d offers the remarkable sports sedan driving performance and everyday versatility of a BMW 3 Series, the X5 xDrive35d offers the poise, control, and safety of a BMW Sports Activity Vehicle®, plus a towing capacity of 6,000 lbs.
• Sales of BMW Advanced Diesel vehicles have increased steadily over the last few months.
• The X5 xDrive35d accounts for 30 percent of total X5 sales so far this year and is the most forward ordered vehicle in the BMW fleet.
• The X5 xDrive35d is the best selling diesel in the premium segment (up 37 percent YTD).
• While the 335d sells less than the X5 Diesel, sales have increased 77 percent compared to the same time last year.
BMW’s Advanced Diesel with BluePerformance technology is a part of a system of integrated technologies called EfficientDynamics (ED). These have enabled the company to make the majority of its new vehicles more efficient and cleaner than the last generation, while improving performance. Other important components of ED include ActiveHybrid technology, electro-mobility in the context of “Project i” and the use of hydrogen as an energy source.
Leading the way:
BMW diesel competence for the US.
Today’s BMW Diesels are characterized by dramatically improved power and performance; fuel consumption and emissions levels – reflecting the principle of BMW EfficientDynamics in every respect.
Through their refinement alone, BMW diesel engines have helped to significantly eliminate reservations regarding the acoustic properties of a diesel engine. In fact, great demand for BMW diesel engines has helped BMW achieve increased market share not just in Europe, but in regions all around the world. In 2009 no less than 63 percent of all new BMWs delivered to customers in Europe are powered by a diesel engine.
While diesel engines of today represent an impressive standard for fuel efficiency and emissions on the whole, BMW Advanced Diesel engines take this a step further, setting the standard for torque and pulling power that could never be achieved by a similar displacement gasoline engine – while consuming 25 percent less fuel on average than an equally powerful gasoline engine.
New generation of diesel technology:
Maximum responsiveness, minimum emissions.
Maximum power, outstanding efficiency: The first BMW Advanced Diesel with BluePerformance is particularly well-suited to combine the driving dynamics and refinement of a premium automobile with the most current and demanding standards for preserving resources and reducing emissions. Featuring exceptional power and torque, the 3.0 liter inline-six diesel is one of the most fuel-efficient engines in its class.
Most advanced exhaust gas management:
Selective Catalytic Reduction.
To optimize emission management, Advanced Diesel with BluePerformance incorporates an oxidation catalyst placed just downstream of the exhaust manifold with a diesel particulate filter housed in the same unit and a Selective Catalytic Reduction catalyst with urea injection. In addition to filtering out even the smallest particles from the flow of exhaust gases, this combination ensures effective reduction of nitric oxides (NOX) by way of a chemical reaction within the exhaust system initiated by the injection of a small dose of urea referred to as Diesel Exhaust Fluid. The ammonia (NH3) generated in this process within the SCR catalyst subsequently converts the nitric oxides (NO and, respectively, NO2) in the exhaust gas into environmentally compatible nitrogen (N2) and water vapor (H2O).
SCR technology by BMW:
Optimized emissions without requiring additional maintenance.
To introduce SCR technology in the vehicle, BMW has developed a two-tank system ensuring convenient use of this new technology with all the benefits and ease required by the customer. The amount of Diesel Exhaust Fluid required in each case is injected from the active tank (approximately 1.6 gallons in volume) by means of a dosage pump. Since the DEF would freeze at a temperature of 12oF this active tank, as well as the dosage pipes are heated.
The active tank is connected to a second reservoir, referred to as the passive tank. With its additional capacity of approximately 4.5 gallons, this passive tank offers a plentiful supply of the DEF. The average range provided with this supply capacity is generally sufficient to have the tank system replenished only when the driver needs to change the engine oil.
Hence, the large amount of DEF stored in the reservoir enables the customer to enjoy continuous driving, without having to change his/her service intervals. The driver therefore benefits from the advantages of this environmentally friendly emission technology throughout the entire running life of the vehicle typically without any additional service or visits to a BMW Center. Since all BMWs sold in the US benefit from The BMW Maintenance Program, the refilling of the DEF tanks will be a no-charge service for the first 4 years or 50,000 miles.
DEF from the active tank is delivered to the dosing valve and atomize into the exhaust system. Consistent distribution of DEF within the flow of exhaust is ensured by the SCR mixer. The ammonia generated in the hot exhaust flow subsequently acts as a reduction agent in the SCR catalyst and converts environmentally harmful nitric oxides into nitrogen and water vapor in a process referred to as a selective catalytic reaction (SCR). This process gives the special SCR catalyst its name.
The control of the SCR system is masterminded by BMW’s powerful engine management computer. A nitric oxide sensor downstream of the SCR catalyst provides feedback on the concentration of NOX in the exhaust emissions.
Due to packaging limitations, the position and location of the DEF tank and refill port varies from one model to another. In the BMW 335d, the active and passive tanks are at the rear of the car, while in the BMW X5 xDrive35d, the active tank is housed in the front right section of the engine compartment, and the passive tank is under the floor next to the transmission. The refill ports in both models are easily accessible to ensure that, should the need arise to replenish the supply of DEF before a scheduled service visit; this can be accomplished neatly and easily.