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California ARB adopting approval procedure for aftermarket DPFs

25 April 2016

At a public hearing on April 22, 2016, the California Air Resources Board (ARB) has adopted a procedure for approving aftermarket diesel particulate filters (DPF) for onroad model year 2007-2009 heavy-duty diesel engines. The adopted text includes amendments to the California aftermarket parts regulations that will make it legal to offer for sale in California approved, non-OEM DPFs for heavy-duty engines. The regulation was proposed in 2014.

The anti-tampering provisions of California Vehicle Code (VC section 27156) prohibit the sale, offer for sale, advertisement, or installation of any device that alters the design or performance of a motor vehicle pollution control system, unless that device has been exempted by the ARB. The adopted text provides such exemption for approved particle filters, and defines a procedure for granting aftermarket DPF approvals. The regulation is intended to provide more market flexibility by legalizing the sales of non-OEM DPFs that can provide a lower cost alternative for California fleets that require replacements of failed DPFs after the OEM warranty period.

The adopted DPF evaluation procedure establishes criteria to demonstrate that an aftermarket DPF is durable, maintains the emissions compliance of the engine, and is compatible with the engine—such that it does not negatively impact the OEM engine or system operation. The procedure includes provisions related to testing for emissions, durability, and compatibility; product and installation warranties; warranty reporting; labeling requirements; audit testing; quality control checks; pre-installation assessments; and recall procedures.

Under the procedure, only one DPF approval is required for an emission control group (ECG), which is defined as all engines by a given manufacturer or a given type of DPF system. The procedure defines seven ECGs: (1) Cummins, (2) DDC, (3) Navistar, (4) Volvo/Mack, (5) Caterpillar, (6) catalyzed DPF + burner, (7) General Motors/Isuzu/Mitsubishi. The procedure requires a “worst case” engine choice within an ECG for testing and field demonstrations of compatibility.

The procedure specifies a standard protocol to test aftermarket DPFs for emission compliance and durability. The protocol includes laboratory aging of the new (degreened) aftermarket DPF for a minimum of 300 hours, followed by a field service accumulation on a representative engine for at least 500 hours. In addition, two further 200-hour field demonstrations are required on different engines from the same ECG.

Emission testing is performed on the OEM DPF—which serves as the reference—and on the aftermarket DPF. The procedure specifies criteria for comparing the OEM and aftermarket DPF emissions, as well as comparing the aftermarket DPF emissions before and after the laboratory aging and field service accumulation.

The procedure requires a two-year warranty on both the DPF and its installation. The warranty must cover customer service and the full repair and replacement cost, including diagnosis, parts, labor and any damage to the engine caused by the aftermarket DPF.

The adopted procedure requires that the aftermarket DPF must be made of the same materials and have similar properties (such as wall thickness, cell density, porosity) as the OEM DPF. However, there is no explicit requirement as to the equivalence of platinum group metal (PGM) loading. It appears possible that approved aftermarket DPFs contain lower PGM loadings than the OEM units they replace, which would result in a lower initial cost of the aftermarket DPF, but could increase the vehicle fuel consumption due to higher demand for active DPF regeneration.

The regulation is currently limited to 2007-2009 engines. It remains unclear if or when the regulation will be extended to model year 2010 and later diesel engines, including engines that use particulate filters in conjunction with urea-SCR systems.

Another interesting question is whether the California rule will have any impact on US federal regulations. Currently, the US EPA has no specific approval requirements for aftermarket DPFs. Any aftermarket emission control device is covered by the EPA’s Memo 1A—Interim Tampering Enforcement Policy (issued in 1974 for LPG conversions of gasoline cars). The memo states that aftermarket devices must provide emission performance equivalent to the OEM system they replace. However, the memo does not specify how such a performance equivalence should be determined, which makes it open to conflicting interpretations.

Source: California ARB