Diesel exhaust particulate matter (DPM) causes cancer and much blame has been put on aging truck and bus fleets. Cost Effective Maintenance have found out that the single contribution to diesel smoke is due to the compounding effects of city driving cycles.
According to Brid Walker, General Manager, Cost Effective Maintenance, prolonged stop-start type operation, with excessive idling in traffic is typical of congested city driving.
Diesel engines are designed to run at a decent load and steady temperature for best fuel efficiency and lowest emissions. This does not happen with city driving and it increases engine deposits. Visible smoke can increase after a few days of continuous city driving.
Cost Effective Maintenance have repeatedly demonstrated that by removing accumulated crankcase and combustion chamber deposits, and introducing keep clean technology, DPMs can be kept at acceptable levels, even under congested city type work.
According to Cost Effective Maintenance, lack of maintenance undoubtedly makes things worse. The city duty cycle itself is the single most important factor in diesel particulate emissions. Sometimes engines are well serviced and in good sound condition, but are smoking excessively or failing emissions tests. In many cases, the owners are advised to have their engines rebuilt to restore emission control. In reality, most of these rebuilds can be avoided.