EPA-420-F-10-028

 May 2010

National Clean Diesel Campaign

www.epa.gov/cleandiesel

Diesel Particulate Filter

Installation

Technical Bulletin

Pre-Installation 

Prior to installing any retrofit device, it is important 

to perform a thorough engine inspection and review 

maintenance records to ensure proper engine operation. 

Vehicles with excessive fuel or lubrication oil consumption 

should be repaired prior to installing retrofit technologies. 

Excessive blowby emissions can be a sign of engine wear 

and further inspection of the engine may be necessary. 

Opacity testing with a smoke meter may also be useful 

to confirm proper engine operation. Prior to installing 

a retrofit, the exhaust system integrity should also be 

confirmed. 

Technology Selection 

To select the best Diesel Particulate Filter (DPF) for a 

specific vehicle it is necessary to identify: 

• Vehicle Type: Highway or Nonroad

• Vehicle Class: School Bus, Class 8A Tractor, Ferry, 

Locomotive, Forklift, etc

• Vehicle Specifications: Manufacturer, Model, Model Year 

• Engine Specifications: Manufacturer, Model, Model Year, 

Displacement, Horsepower, Engine Location on Vehicle, 

Turbo-charger, Exhaust Gas Recirculation (EGR)

• EPA Engine Family Name: Can be found on the engine’s 

emission label and contains 12 or 13 characters such as 

TCP7.2RZBDBRB or 3NVXHO466ANA

• Annual Miles Traveled (Highway) or Annual Hours of 

Operation (Nonroad)

• Engine-out PM emission levels 

• Engine duty cycle and the resultant exhaust temperatures. 

• Any unique vehicle, equipment or engine operation that 

may create unusual conditions on the exhaust system or 

DPF. Conditions such as high vibration or shock loading 

may warrant special consideration in DPF selection and/or 

mounting. 

The United States Environmental Protection Agency (EPA) 

and the California Air Resources Board (CARB) maintain 

lists of verified diesel retrofit technologies that define the 

specific applications and engine operating criteria that 

must be met to successfully apply a particular retrofit 

technology (www.epa.gov/otaq/retrofit/verif-list.htm). 

When installed as described on the verified technologies 

list and within the verified scope of coverage, a device 

is expected to achieve the verified performance and 

durability. 

Exhaust Temperature Data Logging 

The exhaust temperature profile is one of the main factors 

in determining whether a passive or active DPF system is 

acceptable for a specific vehicle or piece of equipment. The 

required minimum exhaust temperatures for regeneration 

of passive DPF systems depend on the filter design and 

often range from 210°C for 40 percent of the time to 260°C 

for 30 percent of the time. Active DPF systems rely on an 

additional heat source for filter regeneration. Therefore, 

active DPFs are not as dependent as passive DPFs 

are on the engine duty cycle and the resultant exhaust 

temperatures typically encountered in normal operation. 

Exhaust temperature data logging must be performed 

on each vehicle. The filter manufacturer or an authorized 

representative must perform the data logging and analysis 

of results. If varying vehicle routes or sporadic work loads 

are used, or significant changes in ambient temperatures 

are expected, data logging under a variety of conditions 

may be necessary to accurately document the duty cycle 

and the resultant exhaust temperatures. Exhaust pipe 

insulation may be used to retain heat. If insulation is used, 

data logging should be performed with insulation installed. 

When data logging, temperature measurements must be 

recorded at the installation location for the DPF. Fleets 

should maintain data logging records for all vehicles in 

case they are needed for later reference. 

Diesel Particulate Filter (DPF) 

installed on municipal truck
Installation 

Installation may be performed by the retrofit supplier, or the 

retrofit supplier may provide training to fleet personnel to 

perform installation. 

In some applications, the DPF matches the dimensions of 

the conventional muffler and can be installed as a muffler 

replacement. In other cases the space available for DPF 

installation on the vehicle or equipment is very restricted and 

the DPF configuration must be custom-designed. Safety, 

visibility, and vibration may also need to be addressed by a 

custom installation. The time required for DPF installation 

will vary depending on the situation and can range from 

two to twelve hours or more for an active system. Special 

equipment or a regeneration station may be necessary for 

some active systems.

Since a DPF typically weighs more and may be larger than 

the muffler, stronger clamps and brackets are required in 

place of those used with the original muffler. Failure to utilize 

appropriate hardware and follow mounting instructions can 

result in a failure of support brackets and damage to the 

equipment or vehicle. To facilitate removal of the DPF for 

cleaning, quick-release clamps are often used at the filter 

element.

Passive DPF systems impose strict requirements on 

exhaust temperatures and must be mounted within a set 

distance from the exhaust manifold, as specified by the 

manufacturer. Exhaust pipe insulation may be used to 

retain heat. Active systems may have more flexibility in 

their installation location. 

Documentation should remain with the vehicle and/or in fleet 

records which lists installation and vehicle information such 

as mileage, opacity readings, date, device model number, 

DPF serial number, installer, etc. Records should also be 

maintained to document when service is performed and 

when the DPF is cleaned. If a fleet moves a DPF between 

different vehicles, records should be carefully monitored to 

identify if a particular vehicle or device appears to require 

different service intervals than another. 

Backpressure Monitoring 

An exhaust backpressure monitoring and operator 

notification system must be installed with every DPF. The 

driver notification system must be installed where it is 

readily visible by the driver during normal vehicle/equipment 

operation. In some cases an additional notification system 

may be installed in the engine compartment to alert 

maintenance technicians of service needs. If exhaust 

backpressure exceeds certain thresholds, the operator 

is notified that maintenance is needed. It is important 

that all vehicle/equipment operators and fleet service 

technicians are properly trained to recognize and respond 

to backpressure warning signals as well as understand 

whether or not the warning signal is continuously displayed 

or only during certain operating conditions. It is also 

important that the backpressure monitoring system be 

periodically inspected to confirm proper operation.