The diesel particulate filter system with combined regeneration and nitrogen dioxide reduction meet Euro 5 emissions.

Germany-based manufacturer of diesel particulate filters, Puri tech has come up with a diesel particulate filter system with combined regeneration and nitrogen reduction. Called as DBS-NO2 System, the technology is a self-cleaning diesel particle filter system that has the ability to give a clear NO2 reduction with a combined active and passive filter regeneration. While the sources at Puri tech state that through the use of a newly developed filter coating, the toxic NO2 emission can be reduced by over 60per cent, the DBS-NO2 is fulfills future requirements in the minimising of NO2 emissions (e.g. VERT / CARB / EPA).

Germany-based Through the automatically controlled regeneration by a diesel injection system (central unit), the DBS-NO2 system can be used even in low load ranges (e.g. stop and go) or in short-term usage. The filter system is offered as factory installed or also for retrofitting. Changing operating conditions for diesel motors present a big challenge in the development of filter systems, explain Puri tech sources. Short-term use of the vehicle and a low motor load in particular prevent a purely passive regeneration of diesel particle filters which are reliant on high exhaust gas temperatures. In addition, the current tier 3 (stage 3a) motors for the off-road area are only permitted a low exhaust gas pressure for the diesel particle filter. Due to the exhaust gas recirculation inside the motor with tier 3 motors, it must be ensured that the filter is not excessively loaded with rust particles. This function cannot be fulfilled by passive filter systems which, for example, work on the CRT principle. Thanks to the automatically controlled filter regeneration in the DBS system with diesel injection, the permanent filter self-cleaning during usage of the vehicle is possible even with low load on the diesel motor. Furthermore, the exhaust gas pressure of the filter remaining low, is avoided. This is a compulsory requirement especially for tier 3 (stage 3a) motors in order to avoid defective motor compoments. Engine manufacturer Deutz examined the Puri tech DBS System with regard to suitability for daily use. Deutz examined the system and accepted it for it's tier 3 motors. Interestingly, highly effective particle filters that are not only adjusted to the performance but also to the spectrum of usage of the motor, and irrelevant to whether the vehicle is a fork lift truck, communal vehicle, construction machine or city bus, the DBS / DAS system can adjust to the changing operating conditions of diesel motors in application.

Germany-based DBS/DAS system is a filter system with 'combined regeneration', which combines an active regeneration (external fuel injection) with a passive component (catalytic filter coating or diesel additive). The filter system is therefore laid out for vehicles and machines that are operated partly with low load (reduced exhaust temperature) or which are in constant short-term usage. With this spectrum of usage, a purely passive regeneration of the filter is not sufficient. Filter regeneration is effected by the DBS/DAS system, electronically controlled and automatically, during operation of the vehicle. Assembly is carried out in place of the silencer. The DAS/DBS System is certified by TRGS, TÜV, KBA and AUVA. Certification by VERT, CARB und EPA (USA) is currently being carried out.

If the vehicle / machine is operated with sufficient load, the system is regenerated purely passively by the catalytic coating (DBS) or by the diesel additive (DAS). Activation of the diesel injection is then not required. However, with low load or short-term usage, the filter is loaded with rust particles and the counter pressure increases. When a particularly low pressure level is reached, the electronic control system automatically activates the injection of diesel and the filter regeneration begins.

Germany-based The pre-filter oxidises the injected diesel catalytically whereby the exhaust gas is heated to > 450° C. The advantages of the system are a permanent regeneration of the filter already at the upper idling of the diesel motor, the constantly reduced exhaust gas counter pressure, the automatically controlled regeneration during operation as well as the layout for a 24 hour continuous operation. The DBS / DAS system is thereby optimumly suitable for stage 3a (tier 3) or EUR-5 diesel motors.

The purely passive regeneration of the DPF-1 DPF-1 (250°C on average) or DPF-2 system (225°C on average) lends itself to average motor working loads. The DPF-1 / 2 systems contain a particularly practice orientated procedure with high reliability. The self-cleaning filter system with permanent regeneration works completely independently and is mounted instead of the silencer.

Due to the catalytic filter coating, the system works simultaneously as a 'combination filter' (as a particle filter and a catalyser), and is laid out for use in continuous operation other than having a high service life. The filter capacity is considerable. Over 95 per cent of the particle mass and the carbon monoxide (CO) are filtered out as well as 99,9per cent of the fine particles and more than 99per cent of the hydrocarbon (HC) is retained or converted to harmless elements.