In recent days, the implementation of the National Technical Regulation on emissions for automobiles, especially for diesel engine vehicles, has received attention from many vehicle owners. Many people expressed concern about the emission measurement method at high revs, especially for vehicles that have been used for many years.
According to Mr. Le Hoai Nam - Deputy Director of the Department of Environment (Ministry of Agriculture and Environment), the Ministry of NNMT is the agency that builds and promulgates national technical regulations on emissions. Meanwhile, the organization of implementation and application of specific measurement methods is under the authority of the Vietnam Register (Ministry of Construction).
The contents directly related to the technical process of emission measurement are monitored and implemented by the registration agency, so this unit has the conditions to closely grasp the actual operation at the inspection centers. However, according to the general principle, all technical regulations after promulgation can be reviewed and adjusted if inadequacies arise during the application process.
In the process of implementation, if there is a problem that needs to be reviewed and improved, ministries, branches and relevant agencies can reflect it for the Ministry of Agriculture and Rural Development to study and adjust. Adjustments are entirely possible, but must ensure scientific, practical basis and proper authority," Mr. Nam said.
In fact, many car owners, especially diesel cars, still have anxiety when it comes to the stage of measuring emissions because the engine must operate at a high rotational speed, which is often described as "running the gas pedal completely". However, according to representatives of the environmental agency, the rate of cars not meeting emission standards in reality is not high. Cases that do not meet standards mainly fall into older cars or vehicles that have not been properly maintained.
For diesel engines, parts that greatly affect emission levels include accelerators, high-pressure pumps and injection pins – details that directly affect fuel injection and emission smoke. When the injection system degrades or operates unstablely, the fuel may not be fully burned, leading to increased emissions.
Representatives of functional agencies also affirmed that the inspection at the maximum rotation range is essentially to assess the actual working capacity of the engine according to the technical parameters announced by the manufacturer, not to exceed the design limits of the vehicle.
A fairly common cause of diesel cars not meeting emission standards is a long-term accumulation of soot in the silencer and exhaust system, even though the engine is still operating normally. This condition is common in cars mainly moving slowly in urban areas or running short distances.
To limit the above situation, the registration agency recommends that vehicle owners should take their vehicles to reputable maintenance facilities to check and clean the exhaust gas treatment system such as diesel particle filter (DPF), catalyst, EGR exhaust gas circulation system, and at the same time clean charcoal soot in the exhaust pipe.
In addition, before taking the vehicle for registration, vehicle owners should allow the vehicle to operate stably on the highway or expressway for about 20–30 minutes. When the engine operates at high speed, the exhaust temperature increases, which will help burn down the soot remaining in the exhaust system, thereby supporting the exhaust gas inspection process to take place more smoothly.
At the registration center, registration officers also perform two acceleration tests before conducting official emission measurements. This step is both to check engine safety and to help blow away the amount of soot remaining in the exhaust pipe.
The Vietnam Register believes that the "cleanning" of emissions needs coordination between vehicle owners and registration units to ensure objective and accurate measurement results.
To avoid cases where vehicles do not meet inspection standards, causing additional time and costs, functional agencies recommend that vehicle owners should proactively inspect and comprehensively maintain before taking the vehicle for registration. Some items to pay attention to include engine oil replacement, air filter replacement, fuel cell cleaning, fluke and high-pressure pump inspection, adjusting the maximum speed of the engine according to manufacturer regulations, and checking the exhaust gas treatment system and related sensors.
According to technical experts, if maintained periodically and operated properly, most diesel cars can still meet emission testing requirements without much difficulty.
