The New BMW Advanced Diesel

[Rod Barajas]

Performance + Outstanding Efficiency
Entering a new era in the company’s mission to deliver ultimate driving machines that combine superior performance with exemplary fuel economy, the BMW Group will debut two vehicle models equipped with the BMW Advanced Diesel with BluePerformance at the 2008 North American International Auto Show (NAIAS) in Detroit – the X5 xDrive35d and the 335d.

Successfully meeting the strict exhaust emissions requirements of the North American automobile market, BMW Advanced Diesel – slated to hit US roadways in late 2008 – will be available in all 50 states. The wide availability of these vehicles marks a significant milestone in the BMW EfficientDynamics strategy, which seeks to offer customers in automobile markets around the world maximum driving pleasure with minimum fuel consumption and emissions.

BMW Advanced Diesel technology is being introduced into the US market in the form of the 3.0-liter inline-six featuring Variable Twin Turbo Technology – an engine widely acknowledged as the unchallenged benchmark for sporting performance, motoring refinement and superior efficiency in other markets around the world. At the 2008 NAIAS, BMW is presenting this 265-hp high-performance diesel engine in both the BMW X5 xDrive35d and the BMW 335d. To ensure full compliance with the demanding emission standards in California and other US states, BMW uses SCR technology to reduce nitric oxides (NOX), enabling nationwide introduction of BMW Advanced Diesel with BluePerformance as a 50-state model (BIN5).

Leading the way: BMW diesel competence for the US.
The history of BMW diesel engines began in 1983 when the BMW 524td was introduced as the fastest diesel in the world. From that starting point, BMW has spent 25 years continuously developing diesel technology. 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 superior motoring refinement alone, BMW diesel engines have helped to significantly eliminate any reservations regarding the acoustic properties of a diesel engine. Indeed, great demand for BMW diesel engines has helped BMW achieve increased market share not just in Europe, but in regions across the world. Today no less than 67 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 dynamism, minimum emissions.
Maximum power, supreme efficiency: The first BMW Advanced Diesel with BluePerformance is particularly well-suited to combine the driving dynamics and motoring 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 and economical engines in its class.

Applying Variable Twin Turbo Technology, a small turbocharger first cuts in at low engine speeds. Thanks to its low inertia, this turbocharger develops boost (and extra power) in response to even the smallest movement to the gas pedal and without the slightest delay. As engine speed increases, the second, larger turbocharger cuts in, developing maximum torque of 425 lb-ft at just 1,750 rpm. Interaction of the two turbochargers is controlled by the particularly efficient, high-performance electronic engine control unit.

In addition to the above Variable Twin Turbo Technology, new technical highlights of BMW Advanced Diesel – presented for the first time in 2007 – include an aluminum crankcase and third-generation common-rail direct fuel injection. Featuring precision-quality precise piezo-injectors to deliver the precise dosage of fuel into the combustion chambers with the smallest volume of pre-injection, the third generation system ensures a particularly clean injection process with optimized fuel consumption, emissions figures and running smoothness.

Given all of these qualities, BMW’s 3.0-liter diesel with Variable Twin Turbo has won the prestigious International Engine of the Year Award multiple times – more than any other prize or acknowledgement. The engine is featured in a large number of models in Europe and is now expanding its global story of success as the BMW Advanced Diesel with BluePerformance.

At the 2008 NAIAS, the BMW 335d featuring Advanced Diesel with BluePerformance for maximum output of 265 hp and peak torque of 425 lb-ft. will provide a clear and convincing demonstration of these qualities. On the road, this means acceleration from 0–62 mph in 6.2 seconds and average fuel economy of 23/33 mpg (city/highway, provisional data).

The BMW X5 xDrive35d, will also debut in Detroit. Like the 335d, the X5 xDrive35d offers sporting character through BMW Advanced Diesel with BluePerformance, while standing out as a high-torque Sports Activity Vehicle with excellent qualities for long-distance motoring. The BMW X5 xDrive35d accelerates from 0–62 mph in just 7.2 seconds and offers average fuel economy of at least 19/25 mpg (city/highway, provisional data).

Now, introducing Advanced Diesel with BluePerformance as part of BMW EfficientDynamics, BMW seeks to continue the progress described in the Environmental Defense Report well into the future, with the same intensity and impact.

Most advanced exhaust gas management: SCR catalyst with AdBlue injection.
To optimize emission management, Advanced Diesel with BluePerformance incorporates an oxidation catalyst placed just downstream of the exhaust manifold, a diesel particulates filter housed in the same unit and an SCR catalyst with the 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 AdBlue. 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 vapor (H2O).

AdBlue technology by BMW: Optimized emissions without requiring additional maintenance.
To introduce AdBlue technology into the car, 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 AdBlue required in each case is injected from the active tank (approximately 1.6 gallons in volume) by means of a dosage pump. And since the urea solution would freeze at a temperature of 12.2oF, 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 urea solution. The average range provided with this supply capacity is indeed sufficient to have the tank system replenished only when the driver needs to change the engine oil. Hence, the large amount of AdBlue 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 car, without any additional service or visits to the workshop. Since all BMWs sold in the US benefit from The BMW Maintenance Program, the refilling of the AdBlue tanks will be a no-charge service for 4 years or 50,000 miles.

AdBlue from the active tank is delivered to the dosing valve and atomize into the exhaust system. Consistent distribution of AdBlue 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 in certain vehicles, the position and location of the AdBlue tank may be varied from one vehicle model to the other. In the BMW 335d, the active and passive tank are at the rear end 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-floor next to the transmission.