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Twin Turbo and EfficientDynamics for 4cyl Petrol and Diesel - 4-cyl Gasoline: Clean and Efficient

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Twin Turbo and EfficientDynamics for 4cyl Petrol and Diesel
4-cyl Gasoline: Introduction
4-cyl Gasoline: High Precision Injection
4-cyl Gasoline: Clean and Efficient
4-cyl Gasoline: Specifications
4-cyl Diesel: Introduction
4-cyl Diesel: Fuel Economy and Variable Twin Turbo
4-cyl Diesel: Specifications
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The new four-cylinder: proven foundation, detailed innovations.
The all-aluminium power unit with its stable bedplate construction and grey-cast iron cylinder liners cast into the cylinders themselves is based on BMW’s proven four-cylinder with fully variable valve drive. The cylinder bore (84 mm/3.31´´  ), piston stroke (90 mm/3.54´´  ) and, accordingly, engine displacement (1,995 cc) are identical, while the compression ratio has been increased from 10.5 : 1 to 12 : 1 in the interest of enhanced performance.
Two balance shafts rotating in opposite directions eliminate any rotational vibration on the four-cylinder and ensure a high standard of smoothness and refinement at all times.One requirement in implementing lean burn operation with a stratified cylinder charge was to redesign the cylinder from the ground up, the piezo-injectors being positioned between the valves at an optimum point relative to the spark plug, despite the confined space available.
A highly efficient charge cycle within the cylinders is ensured by conventional valve drive with two overhead camshafts and roller-type drag arms optimised for minimum friction. Compared with engine variants featuring VALVETRONIC, this type of valve management allows a significant increase in engine speed by 800 rpm to 7,000 rpm. To maintain a “beefy” torque curve throughout the entire engine speed range, both camshafts come with double- VANOS for infinite adjustment of valve opening times. In order to build up high torque as soon as possible at low engine speeds, in turn, the engine also incorporates a special intake system with variable manifold length (DISA technology).


Clean and efficient: NOX storage catalysts.
The new lean burn engine comes with a main catalyst close to the engine itself and storage catalysts further down the line to avoid NOX emissions.
Introducing this wide range of innovations serving to reduce both fuel consumption and emissions from the engine, BMW is once again proving its outstanding skills and competence in the area of engine design.
The progress achieved on the new four-cylinder petrol engines in terms of both efficiency and emission management are also an important step in the further reduction of fleet consumption and emissions with BMW’s new cars.
In this way BMW is clearly expressing its commitment to keep the promise made voluntarily by the Association of European Automobile Manufacturers (ACEA) to reduce the average CO2 emissions of newly registered passenger cars in European car fleets to 140 grams/kilometre by the year 2008.
A wide range of improvements in the area of drive technology, aerodynamics and lightweight construction already introduced by the BMW Group already ensures a significant reduction of fuel consumption and CO2 emissions by BMW cars. Hence, the BMW Group has already made its contribution to the voluntary commitment assumed by the Association of the German Automobile Industry (VDA) to reduce fuel consumption by 25 per cent in the period between 1990 and 2005, even outperforming the commitment made by achieving a reduction of approximately 29 per cent. The introduction of VALVETRONIC technology alone in all new petrol engines has reduced fuel consumption in the EU test cycle and, accordingly, CO2 emissions by approximately 10 per cent. The significant effect of this progress in technology also comes out clearly in a more long-term comparison: Fuel consumption of the entry-level model in the BMW 3 Series with its four-cylinder petrol engine was reduced by 22 per cent from 1983–2003, while at the same time the cars involved gained 32 per cent more weight on account of greater safety and comfort requirements. In the process the emissions relevant to the determination of exhaust standards have been reduced by an even more significant – and quite remarkable – 95 per cent.
The new family of BMW four-cylinder petrol engines is being introduced initially only in the European markets, since a complete supply of sulphur-free fuel over the entire area is guaranteed only here – and this is essential for the NOX storage catalysts on the engines. European customers will nevertheless be able to use their cars also in other countries where sulphur-free fuel is not yet available everywhere, the only drawback being that there the engines will not be able to fully capitalise on their particular economy benefits and technologies, since the storage catalyst, running under such conditions with sulphur in the fuel used, will require a regeneration cycle more often than is otherwise the case.
High Precision Injection operating in the lean burn mode can therefore only be introduced step-by-step also in other markets when such environmentally-friendly fuel is also available in those countries. Precisely this is why VALVETRONIC will continue to play an important role in BMW four-cylinder engines also in future, offering excellent conditions for extremely economic operation of the engine in the same way as before.
Indeed, emission management by the latest generation of BMW’s four-cylinder power units with VALVETRONIC has now been optimised once again, with modifications, inter alia, of the engine management, the cylinder head cover, exhaust technology, and the injection valves. And last but not least, the optimisation of weight ensured by consistent lightweight engineering also helps to further improve the efficiency of BMW’s four-cylinder power units with VALVETRONIC.

Last Updated on Monday, 09 April 2007 13:58  

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