Harnessing the latest in-cylinder, external and SCR technology, Volvo CE is complying with the tough new Stage IV/Tier 4 Final emission legislation.
Volvo Construction Equipment has developed and rigorously tested a new engine system that meets the demanding Stage IV (EU) and Tier 4 Final (US) emission reduction requirements that came into force on January 1st 2014. For engines 56 kW (75 hp) and greater, Volvo CE meets the legislative requirements through a combination of in-cylinder and external solutions as well as selective catalytic reduction (SCR) technology. The company has already recorded more than 20,000 hours of testing in its articulated haulers, wheel loaders and excavators as well as engine test benches. The new generation of Volvo engines deliver improved fuel efficiency while meeting all quality, efficiency and reliability targets.
The Stage IV and Tier 4f legislation states that nitrogen oxide (NOx) levels must be reduced from the current Stage IIIB/Tier 4 interim levels of 2.0g/kWh to 0.4g/kWh –representing a 80% decrease. To meet this new requirement, Volvo CE has applied SCR – a technology that Volvo Trucks has used since 2005. The Volvo solution incorporates an after treatment catalyzer which reduces NOx levels by injecting a urea and water-based reduction agent. When the reduction agent, which is known as AdBlue in Europe and Diesel Exhaust Fluid (DEF) in the US, is heated by the exhaust it produces ammonia. This causes a chemical reaction in the catalyzer which converts NOx to nitrogen and CO2 – both of which are naturally found in the air.
For most engine models, Volvo CE will use SCR in addition to the current diesel particulate filter (DPF) and exhaust gas recirculation (EGR) technology the company developed to meet the Stage IIIB/Tier 4i legislation – which came into force on January 1st 2011. Particulate matter will continue to be reduced through an advanced exhaust after treatment system. However, the updated DPF system will operate with advanced electronic control technologies and increased passive regeneration. This means that in most cases, the particulate matter collected in the DPF will gradually be oxidized at low exhaust temperatures during machine operation. Active regeneration – where the system actively triggers and controls the regeneration process in order to incinerate the particulate matter at high temperatures – will only take place if the particulate matter is not burnt off at a sufficient rate via the passive system.
MEETING THE CHALLENGE
Despite the fact that construction equipment now requires an additional ‘fuel’ (in the form of a reduction agent) to meet the legislation, operational costs are expected to decrease in most applications – such is the efficiency of the new Volvo engine systems. The reduction agent usage corresponds to approximately 5% of the diesel usage. To maintain maximum uptime, the tank sizes are perfectly matched so that refilling can take place during the same fuel stop. As with the diesel tank, a gauge on the dashboard informs operators of the reduction agent levels.
“Volvo CE was the first equipment manufacturer to produce Stage IIIB/Tier 4i compliant machines and we’re 100% committed to launching our Stage IV/Tier 4f machines from January 1st, 2014,” says Anders P. Larsson, executive vice president of Volvo CE’s Technology function. “We have rigorously tested and validated our new engine systems to ensure they comply with all quality, efficiency and reliability targets. Customer requirements such as machine uptime in all operating conditions, fuel efficiency and ease of operation will be met by our solution. Volvo’s technology will bring significant benefits to the environment and our customers.”
The Volvo Group is among the world’s largest manufacturers of diesel engines in the 9 – 18 liter range for both on-road and off-road operation. “We are extremely fortunate to have the strength of the Volvo Group behind us and all the benefits of shared technology,” concludes Anders. “Volvo CE has capitalized on the vast experience within the Volvo Group and the millions of hours of real world testing the technology has already been through. This helped us adapt the solution for construction equipment – and ensure it functioned with the required performance and reliability levels in all the applications, climates and environments our customers operate in.”