SubscribeIncorporating closed crankcase ventilation (CCV) filtration solutions into engine designs can reduce costs considerably for OEMs.
In addition to potentially increasing engine performance for vehicle operators, explains Adam Pearce, Product Manager at Parker Hannifin’s Racor Filter Division Europe.
With reducing crankcase emissions in order to limit the amount of environmentally harmful hydrocarbons (HC), nitrogen oxide (NOx) and particle matter (PM) that is emitted by new vehicles now essential for achieving Euro 4 compliance, OEMs are investing in the latest closed crankcase ventilation (CCV) filtration systems. However, in most cases, off the shelf filtration products are added to the engine in the later stages of system design; while this method typically offers the desired reductions in blow-by gases, it is rarely the most efficient or cost effective solution, requiring bespoke mounting systems to be built to make the standard filters compatible with specific engine designs.
An alternative approach, now being taken by many OEMs, is to incorporate CCV filtration into the early stages of design, enabling engine manufacturers to make considerable savings and even improve system efficiency in the process.
The Need for CCV (Closed Crankcase Ventilation) Filtration
Crankcase blow-by gases are the second biggest emitter of pollutants on conventional open crankcase vehicles, after the exhaust system itself, releasing into the atmosphere a combination of unburned fuel and exhaust gases, mixed with oil aerosol, soot particles and displaced air. While many manufacturers of these vehicles use baffles to reduce the oil content of the gases prior to emitting the remaining mixture into the atmosphere, this has no affect on the gaseous pollutants present, and only reduces oil content by around 50%.
A more effective option is to close the crankcase circuit, re-circulating the exhaust gases back into the combustion cycle prior to the turbo. While this offers a solution to the emissions issue, it introduces a new set of problems to be overcome. Firstly, as the oil mist, particles, soot and liquid volatiles that are present in the gases also get returned to the combustion process, the turbo and intercooler are coated with oil and soot, which potentially reduces fuel economy, power output and ultimately component reliability. Secondly, if the oil mist from the blow-by is not separated and collected before re-circulation, a significant increase in oil consumption occurs.
To avoid these problems some form of closed crankcase ventilation filtration is required. The latest range of CCV filtration systems, from leading manufacturers such as Parker Hannifin, has been specifically developed to filter the blow-by gases simply and effectively. They function by coalescing and separating the oil mist, particles, soot, and liquid volatiles from the blow-by gases; providing a sump chamber and check valve to enable coalesced liquid oil to be returned to the engine oil sump; and balancing the pressure in the crankcase when the air-flow is returned back to the variable vacuum created by the turbo.
An Integrated Approach
While these products offer a quick and simple standardised solution, they do require a degree of work on behalf of the OEM in order to make them compatible with specific engine designs; in particular, bespoke mounting systems are required, incorporating purpose made seals and components, to ensure that the filtration systems are able to operate effectively. Designing and producing these mounting systems can result in extended timescales and increased costs for OEMs, which is why many are now taking a more integrated approach, working with the manufacturers of CCV filtration solutions early in the design process, to build more efficient bespoke units.
This close collaboration enables a CCV filtration system to be located in the optimum position on the engine, such as the crankcase or fly wheel housing, for more effective filtration and efficient operation. CCV filtration solutions can also be incorporated into the engine block or valve cover; by integrating the design of the filtration system and engine components in this way, OEMs can significantly reduce the costs of materials and offer a more compact and cost effective closed crankcase solution.
Fine Tuning the CCV Filtration for Improved Performance
In addition to reducing costs, fine tuning the CCV filtration solution for an engine can have a significant impact on system performance and efficiency. In particular, the position of the filter affects the characteristics of the blow-by gases, so by positioning the filtration system in the optimum location, manufacturers can influence and take advantage of the distribution of particle sizes in the gases.
For example, if a CCV filter is integrated into the top valve cover, the engine geometry effectively does much of the work for it, with heavier particles dropping out of suspension. This can extend the life of the filter considerably, resulting in consistently high performance and reduced costs.
The Complete CCV Filtration Solution
Many OEMs are now taking the integrated approach one step further, sourcing integrated assemblies that include a finished valve cover, incorporating the CCV filtration solution. These systems can simply be bolted on to engine housings, significantly reducing production time, resource and money. With major global suppliers, such as Parker Hannifin, specialising in a wide range of engineering sectors, from seals to filtration, a high quality, purpose built complete solution can be quickly and cost effectively achieved, with minimum research and development on behalf of OEMs.
Conclusion
For OEMs looking to incorporate crankcase ventilation systems into their engines the challenge lies in finding a balance between performance and cost. By communicating effectively with the manufacturers of the latest CCV filters, from the early stages of development, a solution can be found that meets both requirements. This new approach results in a fully bespoke solution that enables emissions legislation to be met simply and within time and cost restraints, in addition to optimising system performance.
Please send all sales enquiries to:
Parker Hannifin plc, European Product Information Centre, Parker House, 55 Maylands Avenue, Hemel Hempstead, Herts, HP2 4SJ. Tel: 00800 27 27 5374.
Email: epic@parker.com
