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Euro VI engines: reliability and low consumption

The Euro VI 11 and 13 L engines which Renault Trucks will be fitting to the vehicles in its new Construction and Long Distance ranges will be the least polluting and the quietest the brand has ever used in its trucks. While developing these new engines, Renault Trucks made every effort to constantly improve their reliability and make sure its customers would benefit from the lowest consumption possible.

The Euro standards identify and govern four pollutants: nitrous oxides (NOx), carbon monoxide (CO), hydrocarbons (HC) and particulates. The Euro VI standard, with which all vehicles registered in Europe after 1 January 2014 must comply, radically reduces the level of these polluting emissions that can be emitted into the atmosphere. Compared with Euro O in 1990, the level of permitted emissions has been reduced by 98% for NOx, 95% for  hydrocarbons, 89% for carbon monoxide and 97% for particulates.

Furthermore, the maximum levels will have to be complied with whenever and however the truck is being used and not simply under "normal" conditions. Finally, the Euro VI standard requires drivers to know what to do in the event of any dysfunction and also that the post treatment system must remain in full working order for seven years or 700,000 km.

Renault Trucks based the development of its new Euro VI DTI 11 and DTI 13 engines on its Euro V blocs and decided to optimise its SCR technology. These blocks, well-known for their efficiency and low consumption, underwent modifications of over 50% and were equipped with an entirely new engine computer. The SCR system was revised and made even more efficient. By using new materials in its manufacture, its catalytic reduction performance has been improved so that NOx emissions can be reduced even more efficiently. It now also features a particulate filter.

These new engines were subject to stringent regular testing to check their development and reliability. At each phase of the design process, highly accurate development and verification tests were carried out in parallel, both on test benches and in vehicles. For example, the engine was subjected to large amplitude temperature increase and decrease cycles in close succession. Moving parts wear and endurance were also tested by running the engines for more than 1,000 hours virtually uninterrupted. In the end, Renault Trucks Euro VI engines will provide the manufacturer's customers with high levels of performance, reliability and low consumption.

Injection

For its heavy duty range, Renault Trucks offers to different engines. The 11 L and 13 L Euro VI blocks are based on the Euro V blocks renowned for their performance, reliability and low consumption.

The DTI 11 is a six cylinder engine with a displacement of 11 L available in three power ratings: 380 hp (1,800 MM), 430 hp (2,050 Nm) and 460 hp (2,200 Nm). Injection is controlled electronically via a common rail. This technology delivers very high precision injection, making it possible to control and optimise combustion under all engine operating conditions.

As far as the DTI 13 is concerned, the injection by electronically controlled pump injectors has been retained. This tried and tested technology has been adapted to the applications for which engines with this displacement have been designed. The DTI 13 is also available in three power ratings: 440 hp (2,200 Nm), 480 hp (2,400 Nm) and 520 hp (2,550 Nm).

On its 11 L and 13 L engines, Renault Trucks has chosen not to use cooled EGR technology. In order to comply with the Euro VI standard, and to rapidly increase engine temperature, even during start-up, the manufacturer has created its own system which involves recycling exhaust gases. These are reinjected, hot, into the air intake. In certain operational phases, this rise in temperature can also be obtained by using the exhaust flap which, by altering the pressure, can quickly increase engine temperature. This ensures good combustion and increases the efficiency of the post treatment system, which requires high temperatures to operate under optimal conditions.

The post treatment

The new post treatment system was incorporated into the design of the new chassis architecture for the new ranges. It consists of three elements: the oxidation catalyser, the particulate filter and the reduction catalyser (SCR). The Renault Trucks engineers have managed to fit these two units into a single, compact box bolted to the chassis. This is one of the smallest on the market, enabling Renault Trucks to offer its customers high-capacity Diesel and AdBlue tanks as well as facilitate the work of body fitters.

The oxidation catalyser

The purpose of the oxidation catalyser is to reduce the hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust gases. By means of a chemical reaction, it transforms 90% of these pollutants into harmless elements which will subsequently be eliminated by the SCR at a later stage in the process.

The particulate filter

As its name suggests, the particulate filter is designed to catch the small particles in the exhaust gases and eliminate 99% of them. They are transformed into soot which is then burnt. This operation is carried out in a regeneration process that is transparent for the driver.

The reduction catalyser (SCR)

This catalyser is designed to reduce emission levels of the last pollutant identified by the Euro standards: nitrous oxides (NOx). Another chemical reaction is used for this purpose, brought about by injecting a urea solution (AdBlue) into the exhaust gases. This converts the nitrous oxides in the gases into Di-nitrogen (N2, a harmless gas) and water vapour. The process enables the system to eliminate 95% of the NOx emissions.

By deciding to renew its entire range of vehicles at the same time as Euro VI becomes compulsory, Renault Trucks has been able to install its new engines directly onto the new chassis, thereby ensuring that they are perfectly integrated. By using tried and tested solutions in association with innovative technologies, Renault Trucks is able to offer its customers less polluting, quieter and highly reliable Euro VI engines offering a level of consumption among the lowest on the market.

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