Scania has introduced its new range of V8 engines.
Dan Boman/Scania
The new engines, which are available at 520, 580, 650 and 730 horsepower, can reduce fuel consumption by 7 to 10 percent according to Scania. The latest V8 engine generation is the company’s response to the growing trend towards heavier, longer trucks. “Vehicle combinations with higher combined truck and trailer weights are a key factor in the shift to smarter transport. They are also the reason behind the trend towards an increased demand for more powerful truck engines”, says Alexander Vlaskamp, Senior Vice President, Sales & Marketing, at Scania Trucks.
While the latest engine generation is based on the same engine block and the same basic configuration as its predecessor, the similarities already end there. The most significant change is with the exhaust gas manifolds that run separately to the turbocharger. On the turbine side, the turbocharger is supplied directly from the respective cylinder banks from two directions. Since three of the engines (with the exception of the 730 hp version) are designed for pure selective catalytic reduction (SCR only) in the exhaust gas aftertreatment system, the V8 engines now have a fixed-geometry turbocharger. This is more robust and lighter than a variable-geometry turbocharger. The turbocharger is now mounted directly onto the engine block, between the cylinder banks, ensuring a more stable and vibration-proof position.
Straighter intake and higher pressure
Major changes have also been made to the intake and injection systems. The air intake is now straighter, and the fuel distributor system is designed as a single rail with a simpler intake via a central high-pressure line and longer distribution pipes that also facilitate access during servicing. The maximum pressure of the fuel distributor system is now lower at 1,800 bar since SCR technology is used in the exhaust gas aftertreatment. As soon as the fuel from the two-piston XPI high-pressure pump is injected into the cylinders via the newly developed injection system, the mixture is more strongly compressed and a maximum cylinder pressure of up to 210 bar is applied, an important prerequisite for reducing fuel consumption.
Lower internal friction
The cylinder head, pistons, piston pins, crankcase, crankshaft and all the bearings have been reworked and now have improved sealing and lower friction. Scania’s modular system enables these modifications to also be used in other engine series. Scania’s latest Euro 6 V8 engine generation is offered with four power levels. By completely reworking the engine and applying new technologies, the fuel consumption could be reduced by 7 to 10 percent.
“We have made refinements and improvements by implementing smarter solutions and better packaging, with the result being that we’ve exceeded even our own goals. It all comes down to a well-harmonised interplay between the hardware and software, and improved calibration. However, amid all these logical changes, I can’t help but mention that the new exhaust gas collectors mean that the classic V8 sound has made a comeback. It’s not louder, but...yes, it’s just right”, says Roger Olsson, Chief Engineer for V8 engines at Scania.
Fewer and lighter components
All four V8 versions designed for the Euro 6 emission standard use a compact and completely integrated silencer that performs the exhaust gas aftertreatment. The silencer contains an oxidation catalyst, an AdBlue mixer, two particulate filters with short filters and asymmetric walls to reduce back pressure, three parallel SCR catalysts and three ammonia-slip catalysts. Despite all these integrated components, the silencer is 900 millimetres wide and does not impede, for example, the installation of the tanks on the side of the frame.
“Using SCR only for aftertreatment provides us with a number of advantages”, says Olsson. One obvious difference is that even fewer and lighter components are required. This, in turn, makes it easier to optimise for the lowest possible fuel consumption, due to there being fewer parameters and components to take into account. And the change to a turbo unit with fixed geometry from the previous variable turbo provides increased efficiency, due to reduced gas-exchange losses.