Atlas Copco introduces new low emission diesels in its latest large paver models - Mike Woof writes
The large pavers from
The machines were designed to house engines meeting the Stage IIIA, Stage IIIB and Stage IV emissions requirements, including the aftertreatment equipment.
These large pavers retain the high visibility design and operator comfort, despite the much larger aftertreatment units now being fitted. To reduce CO2 and HC a diesel oxidation catalyst (DOC) is placed in front of the selective catalytic reducer (SCR) in the exhaust stream. The system features advanced sensors to provide a full closed loop control. The dosing levels of AdBlue, the diesel exhaust fluid (DEF) are minimised due to enhanced mixing in the decomposition reactor tube (DRT).
The SCR system is a copper zeolite-based catalyst and due to efficient particulate matter reduction there is no need for a particle filter. Meanwhile, the DOC system is installed once and requires no further maintenance.
The Dynapac SD2550CS offers a number of features designed to boost operator comfort and control, with an ergonomically designed dashboard. This is said to feature easy to understand analogue signs in its digital display. To make work easy for screed operators wearing gloves, the smart screed remote controls also have toggle switches for screed extensions and for the levelling cylinder function. A camera system is fitted in the dash that offers a 360° view, providing the operator even greater control over the paving job.
The upgraded Pave Manager 2.0 operating system, with colour display, offers new features such as direct access buttons to key functions on the main dashboard, improved display of screed control as well as additional paving functions.
The Dynapac SD2550CS is suitable for highway paving and can handle widths up to 14m, with a theoretical production capacity of 1,100tonnes/hour. The heating system with a 60kW generator and the screed heating system ensure faster heating up to the full working width. A number of screeds are suitable for the Dynapac SD2550CS paver: the Dynapac V5100/6000 TVE (tamper vibration) screeds; V5100/6000TVH (high compaction) screeds; as well as the Dynapac R300TVE rigid screed. The R300TVE is a tamper vibration rigid screed with a basic width of 3m that can be extended using mechanical extension boxes up to a maximum width of 14m.
In order to operate with variable paving width, the screed can also be offered with hydraulic extensions at the end, which are 1.3m wide and would extend to 2.6m maximum width. This screed is designed to offer a smooth surface finish due to its rigid construction.
The 15tonne capacity hopper is 2.6m deep, while the machine has a 1.3m wide material tunnel and a 500mm diameter auger system to provide the smooth flow required while paving wide sections. The paver is also available with a large material hopper and, when used together with the new Dynapac MF2500CS feeder, the paving performance can be 30% higher. A special bumper with hydraulic push rollers is also fitted that prevents damage from truck impacts during loading.
The novel VarioSpeed system is said to ensure optimum engine speed, helping save fuel by around 15% while also extending machine life. This is an optional RCE patented drive concept that recognises the required rpm for the application, using a computer to sense and control engine speed. Any SD Paver can be upgraded to VarioSpeed and this is offered as a retrofit package. In addition, the hydraulic drive system features thermostatic fan control for efficient cooling while the machine runs on tracks with 320mm wide pads that maximise grip and wear life.
