Emission Systems
LCV Exhaust SystemsNearly 10% of all vehicles on UK roads are Light Commercial Vehicles (LCVs), with a parc of over 3,500,000 vehicles.* Despite a drop in the number of new LCV registrations during 2009, the LCV parc has still achieved growth of approximately 17% between 2005-2010. LCV Issues LCVs are ‘working vehicles’ so they typically have a tougher life than passenger cars. Covering short-to-medium distances through urban areas with lots of engine stop-start every day prevents the exhaust system from reaching its optimum operating temperature; this in turn makes the LCV exhaust extremely vulnerable to internal corrosion because the temperature which allows internal condensate to evaporate has not been reached.
LCV vehicles are not typically driven by the owner of the vehicle and therefore tend to be less well looked after than cars. Consequently they are more prone to damage, such as damage to the exit pipe from bad parking, or even collision damage on under floor catalysts from speed humps. As a result, LCV systems tend to have a relatively short lifetime. Generally, most LCVs have diesel engines and are therefore subjected to a lot of engine vibration. The exhaust system components, including hangers and mounts, must be very robust to withstand the intense vibration. Apart from this, the general construction and materials are the same as for passenger cars.
Exhaust system overview The exhaust system has 4 roles: 1) To reduce the pollutants contained in exhaust gases 2) To reduce noise levels in line with legislative requirements 3) To direct hot gases away from the engine and passenger compartments 4) To control and improve engine performance Silencer – limits the noise and back pressure in the exhaust system by cooling and reducing the velocity of hot gases and by tuning out problem frequencies. The silencer chamber contains a series of perforated pipes, baffles and absorption material specifically tuned to each application Pipes – route the gas from the engine manifold to the tailpipe exit, directing the hot gases away from engine and passenger compartments Clamps & fittings – join the various pieces of the exhaust system together Catalytic converter – as harmful gases travel past the catalyst element they are converted into cleaner gases Diesel particulate filter – collects particulate matter (black soot), which is then burned away during periodical regeneration Noise Issues Legislative requirements for LCV are generally similar to passenger cars. Vehicles up to 3.5t fall into the same noise limits for tailpipe and drive-by noise of 74 decibels (dB). The drive-by noise limit for vehicles with direct injection diesel engines is 1dB higher at 75dB. Otherwise, LCV must pass the same rigorous type approval tests as passenger cars, to ensure that performance is equivalent to the OE for durability, noise and back pressure.
Most diesel vehicles now have a turbo which functions like a small silencer: the gases pass through due to the speed of the blade ‘smoothing the turbulence’ in the gases. For this reason, these turbo systems are generally easier to tune than non-turbo applications and have more simplified internal designs. LCV from Klarius Klarius currently has a catalogue of over 1,000 parts for LCV and is investing heavily in the development of this range. Recent additions include new systems for Transit, Sprinter, LDV Convoy and Iveco. |
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