BluePerformance = Clean Diesel Engine Strategy EfficientDynamics = Vehicle Design Strategy reduce CO2 improve fuel economy preserve Ultimate Driving Machine performance Environmental Defense Fund www.edf.org European Federation for Transport and Environment www.transportenvironment.org

Fuel System “Heart”

Intake system “Lungs”

Exhaust System “!”

Third Generation Common Rail Injection Traditional diesel engines use a high pressure fuel injection pump with lots of moving parts and a separate injection pipe to each cylinder. These injection pumps generate some noise, require critical calibration and lubrication, periodic maintenance, and were mechanically limited to one injection of fuel per cylinder stroke. As shown in the illustration, we’ve eliminated these shortcomings and use a third generation of common rail, ultra-high-pressure injection, with piezo-electric injectors. It’s called “common rail” because there is just one common fuel feed pipe (or rail) for all 6 injectors. That’s the green pipe shown in the illustration. So “common rail” just means that there’s no more mechanical injection pump with its separate fuel pipes. No maintenance, less noise, and more control. The diesel fuel injection pressure is 1800 bar, which is about 26,000 psi. The ultra high pressure means that the fuel spray into the cylinder can be very finely atomized. The smaller the injected fuel particles, the better the burning process because the fuel can better mix with oxygen. 2 2

Third Generation Common Rail Injection Traditional diesel engines use a high pressure fuel injection pump with lots of moving parts and a separate injection pipe to each cylinder. These injection pumps generate some noise, require critical calibration and lubrication, periodic maintenance, and were mechanically limited to one injection of fuel per cylinder stroke. As shown in the illustration, we’ve eliminated these shortcomings and use a third generation of common rail, ultra-high-pressure injection, with piezo-electric injectors. It’s called “common rail” because there is just one common fuel feed pipe (or rail) for all 6 injectors. That’s the green pipe shown in the illustration. So “common rail” just means that there’s no more mechanical injection pump with its separate fuel pipes. No maintenance, less noise, and more control. The diesel fuel injection pressure is 1800 bar, which is about 26,000 psi. The ultra high pressure means that the fuel spray into the cylinder can be very finely atomized. The smaller the injected fuel particles, the better the burning process because the fuel can better mix with oxygen. 2 2

Traditional diesel engines use a high pressure fuel injection pump with lots of moving parts and a separate injection pipe to each cylinder. These injection pumps generate some noise, require critical calibration and lubrication, periodic maintenance, and were mechanically limited to one injection of fuel per cylinder stroke. As shown in the illustration, we’ve eliminated these shortcomings and use a third generation of common rail, ultra-high-pressure injection, with piezo-electric injectors. It’s called “common rail” because there is just one common fuel feed pipe (or rail) for all 6 injectors. That’s the green pipe shown in the illustration. So “common rail” just means that there’s no more mechanical injection pump with its separate fuel pipes. No maintenance, less noise, and more control. The diesel fuel injection pressure is 1800 bar, which is about 26,000 psi. The ultra high pressure means that the fuel spray into the cylinder can be very finely atomized. The smaller the injected fuel particles, the better the burning process because the fuel can better mix with oxygen. 2 2

2 Power applied to piezo crystals… crystals expand and open balance valve 3 High pressure above injection valve released so high pressure under valve pushes up, lifting injection needle and allowing fuel injection 1 Injection valve in hydraulic balance, injection needle closed Traditional diesel engines use a high pressure fuel injection pump with lots of moving parts and a separate injection pipe to each cylinder. These injection pumps generate some noise, require critical calibration and lubrication, periodic maintenance, and were mechanically limited to one injection of fuel per cylinder stroke. As shown in the illustration, we’ve eliminated these shortcomings and use a third generation of common rail, ultra-high-pressure injection, with piezo-electric injectors. It’s called “common rail” because there is just one common fuel feed pipe (or rail) for all 6 injectors. That’s the green pipe shown in the illustration. So “common rail” just means that there’s no more mechanical injection pump with its separate fuel pipes. No maintenance, less noise, and more control. The diesel fuel injection pressure is 1800 bar, which is about 26,000 psi. The ultra high pressure means that the fuel spray into the cylinder can be very finely atomized. The smaller the injected fuel particles, the better the burning process because the fuel can better mix with oxygen. 2 2

Sequential Twin Turbo Technology The next main system is the “lungs” of the engine….the twin turbo charger package seen here on the right side of the engine 2 2

Compact Design Small turbo Waste gate Large turbo Up close you can see that there is one large and one small turbo. The turbos operate in a sequential manner for smooth power delivery and a very flat torque curve. Sequential means that the small turbo operates at low engine speeds, both turbos operate at mid-range speeds, and the large turbo operates at higher engine speeds. Twin turbos are expensive, and as you might expect, the next big step in development will be to get the same seamless performance with only 1 turbo. Large turbo 2 2

BMW Advanced Diesel Technology Sequential Twin Turbo Technology Low Speed All three butterfly valves are closed. These next four slides will show you the sequences for the twin turbo system. In the schematic, the blue flow indicates intake air and the red flow indicates exhaust. You can see the large and small turbo, and 3 butterfly valves, here shown all closed at low rpm. In this mode, all intake air goes past both turbo compressor wheels and all the exhaust goes past both turbines. The small turbo with its lower inertia is spinning fast and providing some boost. Intercooler

Turbine bypass for small turbo BMW Advanced Diesel Technology Sequential Twin Turbo Technology Low-Mid Range Turbine bypass for small turbo begins to open turbine bypass In this sequence we see that at about 1500 rpm, the turbine bypass butterfly valve for the small turbo begins to open. This allows more exhaust energy to reach the large turbo and get it spinning faster. Both small and large turbo are now providing a share of the boost. Intercooler

BMW Advanced Diesel Technology Sequential Twin Turbo Technology Mid Range Turbine and compressor bypass valves for small turbo are fully open turbine bypass At mid-range engine speeds the turbine bypass for the small turbo is fully open and the large turbo provides the boost. compressor bypass Intercooler

BMW Advanced Diesel Technology Sequential Twin Turbo Technology High Speed All three valves are fully open including the large turbo waste gate waste gate turbine bypass At high speeds the turbo can put out more boost than needed, so a waste gate valve opens and some exhaust can bypass the turbine to prevent over-pressurization. In summary, the large and small work together in sequence to deliver seamless performance through the full range of engine operation. compressor bypass Intercooler

Selective Catalytic Reduction (SCR) DEF (Urea) tank Urea Dosing module The next major system is the exhaust system….and it plays a critical role in minimizing emissions. Efficient pollution control means that the exhaust must pass through 2 catalysts and one particulate filter. Here’s a schematic of the system. Starting from the left, the exhaust leaves the engine and turbochargers, and enters an oxidation catalyst. It’s a 2-way catalyst that reduces carbon monoxide and hydrocarbons. 2-way means it reduces 2 separate pollution gases. The oxidation catalyst is placed close to the engine so that the exhaust is hottest and the cleanup reaction is improved. Oxidation catalysts are typically made up of a ceramic honeycomb with a thin coating of a precious metal like platinum. They’re very expensive. The same canister holds a particulate filter that collects and burns up soot and larger carbon particles. A particulate filter is usually made up of a special ceramic honeycomb so it holds the soot in kind of a screen so it can heat up and completely burn. From there, the exhaust passes by the SCR dosing module where a computer control will periodically send a signal to inject some diesel exhaust fluid (DEF) into the exhaust gases. This mixture passes through a finned mixer plate and then into the SCR catalyst where a chemical process changes NOx into nitrogen and water vapor. Mixer Oxidation catalyst Diesel Particulate Filter SCR-catalyst

The crankcase ventilation system is heated and monitored to make sure it’s always attached.

The torque converter has twin axial spring dampers that smooth the flow of power when the transmission coupling is locked up.

Because a diesel engine uses fuel so efficiently, there is very little heat released to the coolant at low power outputs. This means that sometimes there won’t be enough hot coolant to heat the occupant compartment in winter. As a supplement for the normal heater system, the X5 and 3 Series diesel models have an electrically activated ceramic boost heater element positioned in the heater box (see the arrow). When coolant heat is not enough to warm the occupants, excess electricity is sent to the heater to boost the output.

To stimulate improved combustion, there are electrically operated swirl valves in the air intake ports.

High pressure EGR 335 d and XDrive35d Low pressure EGR XDrive35d only To reduce the production of NOx during the combustion process, the 335d and XDrive35d both have a high pressure exhaust gas recirculation system. Because it has towing capability, the XDrive35d also includes a low pressure EGR. Both the low and high pressure EGR systems are water cooled by the engine coolant for improved efficiency. Low pressure EGR XDrive35d only

The DEF or diesel exhaust fluid for the SCR system is stored in two separate reservoirs. There is an active and passive reservoir. Shown here are the active reservoirs which are heated, because DEF liquid will freeze at temperatures below about 12 degrees fahrenheit. The active reservoirs supply the needed DEF, and the passive reservoirs refill the active resevoirs as needed.

And last but not least we come to the misfueling protection system. The reduce the chance that gasoline is mistakenly filled into the diesel fuel tank, there is a misfueling protection system installed. A standardized gas station nozzle is 21 mm in diameter and a standardized diesel fueling nozzle is 24 mm. If a nozzle smaller than the correct 24 mm diesel nozzle is used, a flap stays closed and prevents filling with gasoline. The misfueling protection won’t let the flap open unless the correct 24 mm diameter diesel nozzle contacts two release buttons and releases the flap lock.

BMW Advanced Diesel Technology Agile, Fuel Efficient, and Clean The Ultimate Driving Machine Rudolf Diesel invented the engine, but we made become a true BMW engine. The Ultimate Driving Machine. Thank you very much for your attention. 2 2