This innovative technology has made it possible to shape the exhaust ducts optimally to allow an optimal gas flow and generate the maximum pulse effect for the highest possible turbine efficiency. The pulse dynamics can thus be utilized to the limits in order to generate a high power output level across a wider range of engine revs. This translates into close to immediate response and good acceleration at both low and high speeds.
“High performance is important to many customers. However, being an innovative and highly efficient powertrain, there is also a significant gain in both fuel consumption and emissions with this technology” says Magnus Jonsson. “A Volvo S80 with this engine and automatic transmission consumes just 8.3 liters of fuel per 100 kilometers.”
Efficient direct injection starts the turbo quickly
The new engine features direct injection. The injectors have seven holes for precisely controlled injection into each cylinder. The injectors are side-mounted.
Direct injection gives a high fill rate in the combustion chamber, efficient combustion and low emissions. Thanks to this high fill rate, the turbo also starts spinning earlier, delivering alert response from low revs. This in turn results in swift acceleration and good driveability even from low speeds.
Direct injection also contributes to quick and stable combustion at high loads, and thus smooth engine operation even when the accelerator is floored.
The injection system is supplied by Bosch.
Twin VVT (Variable Valve Timing)
Volvo's new GTDi engine utilizes variable timing for both camshafts. Both the inlet and the exhaust valves' opening times can be varied to optimize the overlap and ensure the correct fill rate in the combustion chamber irrespective of engine revs. This gives the combustion process maximum efficiency throughout the rev range and helps generate rapid acceleration at all speeds.
Both VVTs are of the conventional vane-type. The rotation of the inner and outer rotor is regulated by hydraulic pressure from the engine oil. By opening and closing the oil control valves, the oil pressure and flow through the VVTs are changed until the desired angular deviation between the inner and outer rotor is achieved. The oil control valves are controlled by software in the Engine Management System using feedback from the cam position sensors.