Scania introduces new generation of more fuel-efficient V8s; addressing needs of heavier, longer trucks
12 June 2017
Scania is introducing a new generation of Euro 6 V8 engines that represents Scania’s response to the growing trend in the transport industry towards heavier, longer trucks. The engines, which are available at 520, 580 and 650 horsepower, can reduce fuel consumption by 7 to 10 percent for customers with vehicles that have higher combined truck and trailer weights, higher average speeds, or both.
The new V8 engine platform ranges from 520 to 650 hp; the current V8 engine platform will still be used for the 730 hp version Scania V8 engine. Each of the new V8s are characterized by advanced technical solutions that contribute to reduced weight, increased availability, and the 7-10% reduction in fuel consumption. The new V8 builds on many of the successful features from the earlier generations. But this time, out of approximately 650 components that make up the entire engine, 200 are completely new.
The cross-functional team that developed the new V8 engine focused on four key areas: fuel efficiency to improve customers’ profitability, serviceability to increase the vehicles’ uptime, improved production processes to increase quality for even better robustness, and a contemporary design to match the New Generation Scania trucks.
While the 16.4-liter cylinder block remains the same, the complete engine weighs approximately 80 kilograms (176 lbs) less than its predecessor. This is mainly due to a simplified engine layout with fewer parts overall—for example, the exhaust gas recirculation unit has now been removed. Consequently, the new V8 trucks have a higher load-carrying capacity.
The new V8 engine meets emissions legislation together with decreased fuel consumption by increased aftertreatment efficiency. This has optimized the engine for fuel efficiency and power to a larger extent than when partly reducing emissions with exhaust gas recirculation (EGR) and conventional aftertreatment system. This also results in better engine breathing, which helps to improve fuel consumption.
The new aftertreatment system includes improved evaporation, improved SCR catalysts (selective catalytic reduction) and an improved diesel particulate filter. The new aftertreatment system is an enabler for reaching Euro 6 emission levels without the need for an EGR.
The new rotated twin scroll fixed geometry turbo is common in the racing industry, but this is its first use in the heavy vehicle industry. The fixed geometry increases efficiency and results in a 0.5% reduction in fuel consumption. The new turbo unit also allows for a higher boost pressure, resulting in improved combustion.
The turbo unit also helps reduce the overall weight of the engine. The exhaust manifolds meet in the turbine housing from both sides instead of meeting in the turbo manifold, as they did in the previous generation, which was a more expensive and heavier solution. With the introduction of a single bank exhaust gas manifold, the overall weight of the engine has been reduced, while at the same time the V8 sound has been improved.
The coolant pump utilizes a viscose coupling that is only engaged when needed. This results in adjustable cooling, which means that less coolant is pumped through the engine when it is not needed. Lower friction losses and the reduced energy used for pumping help to decrease fuel consumption by up to 0.5%.
A new pilot-controlled oil pump adapts the oil pressure to the necessary amount at every moment. This helps to minimize the friction losses in the engine and results in a 0.5% reduction in fuel consumption.
The introduction of an oil thermostat has reduced the fuel consumption between 0.5 and 1%. The thermostat provides faster oil-pressure build-up during cold starts and, more importantly, maintains an optimal oil temperature under normal operation.
The Miller camshaft used in the new 520 hp V8 engine reduces airflow through the engine at low load. This in turn increases the exhaust temperature, which helps to reduce the fuel consumption by 0.5%. At high load, compression work is moved out from the engine to the turbo compressor. More energy is extracted from the exhaust gases, which increases engine efficiency. This is possible because the inlet port is held open for a longer time and the effective inlet stroke is shorter than the expansion stroke. This will over-expand the in-cylinder gases, with more power to the crankshaft for the same amount of fuel.
A new clutch compressor engages automatically when needed. This helps to reduce fuel consumption by approximately 0.5%, while at the same time reducing noise emissions.
Although the 730 hp V8 is still based on the current engine platform, it has not been left untouched. The updated 730 hp will, for example, feature the pilot-controlled oil pump, the variable water pump and the new larger aftertreatment system as well as an updated engine management system, which will improve its fuel efficiency—especially at low load.