DAF enhances New Generation trucks
The New Generation XFC (construction) and XG+ (long haul) trucks
Miller valve timing is among the enhancements that Paccar subsidiary DAF has introduced so its New Generation XG+, XG, XF, XFC, and XD trucks can meet the 2025 EU VECTO fuel consumption target of a 25 per cent reduction in fuel consumption from 2019 figures.
DAF’s MX-11 and MX-13 engines (370 – 530 hp) will incorporate Miller timing, which keeps the intake valves open for longer than would be normal on a conventional four-stroke engine.
By only closing the inlet valves some 20 to 30 degrees after bottom dead-centre on the compression stroke, part of the intake charge is forced back out of the combustion chamber and into the manifold. The amount of air forced back is regulated by pressure from the engine’s turbocharger.
This reduces the temperature of the intake air, making it denser and increasing oxygen content without increasing pressure, allowing an earlier ignition event and yielding greater fuel efficiency as the engine’s expansion ratio is now greater than its compression ratio. A further benefit is reduced NOx production thanks to the consequent reduction in combustion temperature.
The engines’ turbochargers and EGR systems have been modified to accommodate the revised valve timing, and new fuel injectors are specified.
Parasitic losses have been reduced by the introduction of a novel waterpump which is electrically-powered during low cooling demand and engine-driven via a belt when there is a high load on the system. Likewise, the twin-cylinder air-compressor has a clutched drive and is engaged only when the air supply needs to be replenished.
DAF is also set to introduce MX engines capable of running on 100 per cent FAME biodiesel in the coming year.
There are further enhancements to the driveline: most notably the pinion of the SR1344 drive-axle has been redesigned so it can be used with the most powerful of the MX-13 engines. A revised shift strategy allows the low-end power of the engines to be exploited to the full: with a 2.05:1 reduction ratio and 315/70R22.5 tyres, engine speeds are reduced by seven per cent, meaning the engine will turn at 950 rpm rather than 1030 rpm at 85 km/h. The SR1344 is also available with a 2.64:1 ratio.
Technical changes reduce parasitic drag and raise gearing
More fuel savings have been gained by the standardisation of Predictive Cruise Control and low rolling-resistance tyres on 4×2 and 6×2 models. Customers who haven’t previously specified these features may benefit from a fuel saving of up to nine per cent, DAF claims.
Further savings could be made with the specification of a factory aerodynamic package which can be tailored to suit all bodywork and trailer types, including those exceeding 4m overall height. Low-deck tractors can now be fitted with factory side-skirts.
Advanced Driver Assistance features include advanced emergency braking (AEBS) supported by three radar systems and a camera, a drive-off assist function which covers the area immediately in front of the truck with an additional radar, and an event recorder which records images and data when the AEBS is activated.
DAF’s Side & Turn Assist covers the trucks’ blindspots all the way to the back of the trailer, there is a lane departure warning, and a speed limit recognition system is standard.
A rear-view camera is also standard, and an emergency stop signal automatically activates the truck’s hazard flashers under heavy deceleration.
Two further driver related features are standard: a drowsiness detector and provision for an alcohol interlock.
All New Generation DAF trucks have a 10-year Paccar Connect subscription. This new online fleet management platform provides real-time information on the performance of the entire fleet and individual vehicles as well as drivers, thereby helping operators to optimise productivity, efficiency and returns. The platform also enables efficient over-the-air vehicle updates.
DAF claims it offers easy integration with existing fleet management systems. This makes it easier to monitor all logistics processes from one device, adding to convenience and comfort for the driver. To achieve maximum efficiency, Paccar Connect also features geofencing, which notifies the home base or destination when a truck nears a delivery location.
