As a diesel particle filter separates solid matter from the exhaust gas stream, it is obviously necessary to somehow destroy or dispose of this in order to prevent the filter from becoming clogged. The process of removing accumulated diesel particulate matter from a filter is known as 'regeneration'. There are many ways of achieving this, each with its advantages and disadvantages. At Blackthorn, we supply and support the following:
Fuel Burners
Fuel burner systems heat the exhaust gas upstream of the particle filter so that regeneration of the filter occurs when required. At Blackthorn we currently only supply the single-point type of fuel burner, which is designed to operate whilst the engine is idling (further technical details are available in the 'technology' section of this website).
A single-point fuel burner comprises the following components:
- A dashboard-mounted console, which informs the operator when regeneration is due and also when it is complete. The console incorporates a switch so that the operator can manually initiate the regeneration procedure.
- A fuel burner, which is supplied from the vehicle's fuel tank
- An electronic backpressure monitoring system linked to a pressure sensor upstream of the filter and to the console.
These products are simple, reliable and easy to install. A Blackthorn engineer will usually make a site visit to carry out the initial set up, test the system and instruct the operators in its use.
Electrical heaters
Electrical heaters for the purpose of regenerating diesel particle filters can be powered by either mains electricity or from an alternator driven by the engine. Blackthorn can supply and support both types. The mains system is often used for diesel particle filters fitted to forklift trucks. It is manually initiated and requires the exhaust section containing the filter element to be removed from the vehicle and taken to a 'regeneration station'. This comprises an electrical heating element, an air blower and a pressure monitoring system. Once the dirty filter is connected to the regeneration station, hot air is blown through it until it is judged to be 'clean' based on the backpressure reading. An additional backpressure gauge mounted on the dashboard informs the driver when regeneration is required. In the case of a typical forklift truck application this will be after 8 hours' running and the regeneration itself will take about 2 hours. Of course if continuous vehicle operation is required we can
supply spare filter elements to enable this.
The use of heaters relying on electricity generated by an alternator attached to the engine permits fully automatic regeneration and eliminates the need for either a mains electricity supply or the shutdown of the engine. However, in most mobile applications the standard alternator is simply not powerful enough. The most important application for this type of regeneration is on standby generators. In these cases additional exhaust heat is normally only required when the generator is running at less than full load, and therefore spare electrical capacity is available. At Blackthorn we can design, supply, commission and support fully automatic regeneration systems of this type.
Coated filters
Silicon carbide wall-flow filters can if necessary be coated with a catalytic material similar to that applied on a diesel oxidation catalytic converter. This has the effect of lowering the temperature required for regeneration and at the same time, reducing emissions of carbon monoxide and hydrocarbons. The drawback is that the coating may lead to higher exhaust backpressure and reduced particle collection efficiency. At Blackthorn, we are happy to discuss the pros and cons of coated filters with potential customers, and to supply and support them where appropriate.
