Engine & Mobile Filtration

Clearing the Air on Global Emissions Standards for On-Road Diesel Engines

Global emissions standards for on-road diesel engines continue to tighten and fuel filtration will continue to play an important role in meeting these new challenges. North America, Europe, Japan and Korea have been hit hardest, although Brazil, Russia, Turkey, Saudi Arabia, China and India have also witnessed the impact of increasing legislation. To gain a clearer picture of emissions standards, individual regions and vehicle categories need to be analysed.

Europe light – medium duty on-road vehicles

Euro 6 started its official introduction in 2014. Most manufacturers had already launched Euro 6 vehicles to comply with regional incentive programmes as early as 2012. The most notable change between Euro 5 and 6 with respect to diesel engines is a significant NOx reduction. This development will drive the introduction of enhanced diesel after-treatment systems (SCR - Selective Catalytic Reduction) as well as increased injection pressures.

Europe heavy duty on-road vehicles

Moving to heavy duty on-road European vehicles, the Euro 6 emissions standards for these engine types came into force in December 2012 for new approvals and December 2013 for all registrations. This standard applies to heavy duty vehicles where the gross weight exceeds 2610 kg (5754 lb).

As engines in this category are used in multiple applications, the test takes place on an engine dynamometer rather than a vehicle dynamometer. Similar to light duty engines, Euro 6 saw a significant NOx reduction compared with the Euro 5 standard. As the fuel system can make a significant contribution to the deterioration of emission systems over time, Euro 6 requires a useful life ranging from 160,000 km (99,400 miles) or five years, up to 700,000 km (435,000 miles) or seven years, depending on vehicle class and load capability.

US light duty on-road vehicles

Tier 3 standards – aligned closely with California LEV III standards – are to be phased-in over the period 2017 to 2025. The structure of Tier 3 standards is similar to the Tier 2 standards: manufacturers must certify vehicles to one of seven available certification bins and must meet a fleet average emission standards for their vehicle fleet in a given model year. The latest standards are more stringent than Tier 2 and include a number of other important changes regarding limits on the sum of non-methane organic gases and nitrogen oxides. Tier 3 standards apply over a useful life of 150,000 miles (241,000 km) or 15 years, whichever occurs first.

US heavy duty on-road vehicles

For heavy duty on-road vehicles in the US, the current emissions standard in force is referred to as EPA10 (40 CFR Part 86). This was first introduced in 2007 with a phase-in to reach full compliance by 2010. Useful life requirements range from 110,000 miles (177,000 km) or 10 years for light-heavy duty diesel engines, up to 435,000 miles (735,000 km), 10 years, or 22,000 hours for heavy-heavy duty diesel engines, with some possible exceptions.


While it’s easy to focus on the requirements for regions that have adopted enhanced criteria emissions standards, lesser regulated markets should not be overlooked when it comes to fuel system demands.

In the industrial engine market it is becoming standard practice to sell the engines/vehicles/machines into lesser regulated countries after several years of operation in the original market. Often ‘de-tier’ kits are applied to the engines to remove systems that are not required in the new market. However, the fuel system is at the heart of the engine and this will normally remain on the vehicle as it enters service in a new market. It should also be noted that fuel quality in these markets can be significantly worse than the original market, therefore the filtration requirements can be different.

In conclusion, all engine sectors from small passenger engines to large marine vessels, have witnessed a focused effort to reduce harmful exhaust emissions. For on-road applications the emissions levels have dropped to the point where further reductions will have smaller environmental impact. As a result, future changes in legislation for harmful emissions will focus on refinements to address specific issues rather than major order of magnitude reductions that have been seen in the past. An example of this could be the introduction of particulate number standards to effectively mandate the use of DPFs (diesel particulate filters) for on-road trucks in the US. However, with harmful emissions standards reaching a plateau, the focus will almost certainly shift towards fuel economy and CO2 reduction. In the past, the main pressure for improved fuel economy has been consumer driven, but now it will be new legislation that mandates fuel economy improvement.

Ultimately, of course, future standards and legislation will only serve to fuel further engine, after-treatment and vehicle technology developments. Moreover, fuel systems will continue to play an important role in the package of technologies being applied to meet the challenge.

This article is a small portion of a study conducted by AVL that was commissioned by Parker Hannifin Racor Division. To download the full 44 page report, Summary of Fuel Injection Equipment With Respect to Diesel Fuel Filtration.

For additional information regarding fuel filtration solutions contact Parker Hannifin Racor Division .

Related posts:

Natural Gas Engines for Heavy-Duty Applications

Filtration Solutions for the Changing Marine Engine Market

How to Protect Your Engine with High Quality Filtration in the Truck and Mobile Aftermarket

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