Engine: Description and Operation: Overview

Overview




The engine has been developed by Volvo.
It is a 6 cylinder transverse in-line engine with a cylinder capacity of 3.2 L for naturally aspirated engines and 3.0 L for turbocharged engines.
After having been relatively unchanged since the introduction 0620, this engine family has been updated on several points. Most modifications have their basis in an effort to achieve lower fuel consumption and thus less environmental impact.
Engine power has increased, at the same time as fuel consumption has decreased.
- B6304T4: (ULEV2 Ultra Low Emission Vehicle): 300(US)/ 304 hp / 440 Nm
- B6324S4 (PZEV - Partial Zero Emission Vehicle): 230(US) 233 hp (torque unchanged 300 Nm)
- B6324S5 (ULEV - Ultra Low Emission Vehicle): 240(US) /243 hp (torque unchanged 320 Nm)
All of these engines meet the emission standards for Euro5.
The engines' idle speed is reduced to 590 rpm on all cars except XC90 which keeps 650 rpm.
The engine is extremely compact. When it was introduced it was the shortest 6-cylinder engine of 3.2 L on the market. Conventional straight 6-cylinder engines are too long to fit between the collision members in the engine compartment. The special design of this engine solves the problem.
The engine has an extremely short drive train, its length is only 625 mm from the front edge of the engine block to the rear edge of the carrier plate.
Great attention has been paid to creating a very rigid engine. Middle part, cylinder block and cylinder head have been structurally optimized to combine low weight with high rigidity.
Even the camshaft cover is structurally optimized.
The engine has double overhead camshafts and 24 valves.
Camshafts, AC-compressor, coolant pump and alternator are driven by an auxiliary unit drive, mounted on the back of the engine.
This placement of the auxiliary unit drive enables new possibilities for creating a good collision-protecting structure around the straight 6-cylinder drive unit. In the latest update of the engine family the servo pump has been replaced by an electrically driven pump (EHPAS), for more information, see Design and function.
The entire engine block and the cylinder head is made from aluminum.
The engine has a compact "pent-roof" designed combustion chamber and V-arranged valves. This gives optimal and fast filling and direct flushing via the inlet manifold followed by the combustion chamber (cross-flow) and the exhaust channel.
The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.
The engine's firing order is 1 - 5 - 3 - 6 - 2 - 4. The firings occur every 120 degrees that the crankshaft rotates.
For information on the engine control module (ECM), sensors, and valves, see Design and Function, Engine Control Module (ECM).