B5254F Information (PDF)

This is a 1MB PDF download filled with info on the Volvo B5254F engine.

The engine in the Volvo 850 GLT is an in-line 2.5 litre five-cylinder called the B5254F. Thanks to an extremely compact design of the engine and transmission (See Technical in- formation Transmission) it has been possible to install it transversely (fig- ure 1), still allowing for excellent han- dling properties and an extremely small turning circle (10.2 metres) for a front wheel drive car of this size. The Volvo 850 GLT is the first passenger car that has an in-line five-cylinder en- gine installed transversely driving the front wheels. Overall length of the complete powertrain, engine and trans- mission, is only 948 mm.

The main characteristics of the B5254F are:

– Five cylinders with four valves per cylinder and a high compression ratio
– High performance and good fuel economy without negative influence on driveability
– Minimized engine vibrations thanks to inherent engine and transmission rigidity, damped engine and suspension system and a separate insulated sub-frame carrying the powertrain.
– A variable induction system, the V- VIS (Volvo Variable Induction Sys- tem) and an extractor type exhaust manifold. Since this is located be- tween the engine and the firewall, the position of the catalyst could be close to the engine which provides faster warming-up of the catalyst and thus low exhaust emissions.

Among the basic development goals for the engine concept were a high degree of reliability and long service life; high energy efficiency; easy maintenance; rational manufacture; compactness in size; low weight and low noise level. As for reliability and service life, the engine has a life span of more than 20 years or a total driving distance of more than 200,000 without needing disassembly and with all vital parts in good working condition.

Regarding high energy efficiency, the gas flow has been optimized with the aid of computer simulations and laser measurement technology in order to ensure efficient use of energy. During the development of the en- gine, Volvo Car Corporation service personnel have contributed with their know-how in order to achieve high re- liability with a minimum of main- tenance.

A number of automatic func- tions minimize the need for manual adjustments:

– Hydraulic tappets (no adjustment of valve clearance)
– Automatic belt tensioners for cam- shaft and auxiliary drives
– Adaptive functions of the control systems compensating for system tolerances and wear, temperature and fuel variations ensuring optimum fuel metering and ignition timing
– Automatic idling speed adjustment and air/fuel ratio

Last Updated on August 8, 2024