W 1998 r the company BMW presented the three-liter, turbo diesel engine, which was installed in the models 5 and 7. In principle, the engine was supposed to be as dynamic as petrol units, had to be quiet, frugal, and at the same time meet the strictest exhaust emission standards. To meet these requirements, it was necessary to apply the latest technical achievements in the field of powering diesel engines. We are talking about the Common Rail system. The power supply of such a diesel engine largely resembles the construction of a multi-point injection system of a gasoline unit. From the high pressure pump, the fuel flows to the central rail, in which it is stored under the desired pressure, independent of the engine speed.
If it is too big, the fuel is recirculated via the valve. The correct pressure value is thus obtained, which allows for optimal combustion. Depending on the needs, the valve is opened using an electronic system and fuel is injected. By controlling the pressure, injection time and timing result in more economical combustion, thus reducing fuel consumption.
Another important problem of diesel engines has been solved in the engine – noise level has been lowered, which is formed during combustion. Thanks to the use of the so-called. In a pilot fuel injection, the combustion chamber is prepared to ignite the mixture. This solution makes it possible to increase the temperature and pressure in the combustion chamber. Additionally, an easier start-up is achieved and the emission of harmful substances is reduced.
Obtaining a full electronically controlled dose of injected oil in practice improves performance and reduces diesel fuel consumption.

Six cylinders of a powerful three-liter, BMW diesel engine, with direct injection, can provide driving pleasure. Powerful engine torque 530 d, equal to 390 Nm, is obtained already at 1750 obr./min. And power, not bad – 184 MILES! In the "seven hundred" model, the power is identical, just a little more torque – 410 Nm obtained from 2000 obr./min. What does it mean? – less advanced people will ask. First and foremost, it's excellent performance, more precisely, good acceleration and even better flexibility. Virtually in any position of the tachometer pointer, when you press the gas pedal, cars shoot forward like a slingshot.
The series was shown on the occasion of the presentation of the new diesel units 7 model 1999, which, compared to its predecessor, has undergone minor cosmetic changes. In the front part of the body, the air intakes have been changed and the headlights have been redesigned, which now resemble those of the series model 3. At the rear, the new "7" has rear lamps and a chrome strip on the trunk lid. The armchairs are interesting, in which, on request, a device for massaging the driver's and passenger's "seat" was installed. Two flat plastic containers are integrated in the seats, in which there is fluid. With the help of an electric pump, the fluid is pumped from one tank to the other, thereby causing a massage.