Working Together for Cleaner Air
Clean Diesel Technologies, Inc.
(formerly Engine Control Systems Limited)
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Retrofit Technologies
| Technology | Engine Model/Application |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) † | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| Purifilter EGR Diesel Particulate Filter (DPF) | Highway; light, medium, and heavy heavy-duty EGR engines, not originally certified or equipped with DPF, originally certified from 2002-2010 and listed in Attachment A enclosed with this letter. | 15 | 90 | n/a | 90 | 85 |
† - Baseline assumes an unmodified engine running on fuel with less than 15 ppm sulfur.
The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:
- As there may be variations from application to application, data logging and a review of actual vehicle operating conditions are required to ensure Purifilter EGR compatibility. The installer must provide the fleet owners and/or operators with a copy of the pre- and post-installation checklists, as well as copies of the data logging results. Fleet owners/operators shall be responsible for adhering to the recommended maintenance schedule.
- The engine exhaust temperature must be at least 240°C for at least 40% of the time the vehicle operates. In addition, the Duty Cycle Index (DCI), as defined by CDTi, must be achieved.
- The engine NOx-to-PM ratio must be greater than or equal to 18.
- The engine must not have engine out opacity greater than 20% as measured by the SAE J1667 Recommended Practice.
- The engine must not have been certified with an original equipment manufacturer (OEM) DPF.
- The engine must be operated on ultra-low sulfur diesel (ULSD) fuel containing at maximum 15 ppm sulfur.
- The engine must be operated with low-ash lubricating oil.
- Fuel additives may not be mixed with fuel unless explicitly approved by EPA for use with this device.
- The engine must be in proper operating condition, well maintained, and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- The vehicle may not be equipped with an oil burning system, and lube oil or other oils may not be mixed with the fuel.
- CDTi installs a back-pressure monitor and logger unit and the remote driver display is visible to drivers while seated in the driver’s seat.
| Technology | Engine Model/Application † |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| AZC Purimuffler or AZC Purifier Diesel Oxidation Catalyst (DOC) | Highway, heavy-duty, 4-cycle engines 1994 through 2006 engines | 15 | 20 | n/a | 50 | 40 |
† - The model year is restricted (with starting year at 1994) for DOCs using certain substrates due to risks with older engines.
The following criteria must be met in order for appropriately retrofitted engines to achieve the aforementioned emission reductions:
- The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.
- The engine exhaust temperature must achieve at least 150 °C during its duty cycle.
- The engine must be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel.
- The engine must not have been originally certified or equipped with a DOC or diesel particulate filter.
| Technology | Engine Model/Application † |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| AZC Purimuffler or AZC Purifier Diesel Oxidation Catalyst (DOC) plus CDTi Closed Crankcase Ventilation (CCV) System | Highway, heavy-duty, mechanically or electronically injected, turbocharged or naturally aspirated, originally manufactured from 1994 through 2006 model years which meet a 5 or 4 g/bhp-hr NOx standard | 15 | 25 | n/a | 50 | 40 |
† - The model year is restricted (with starting year at 1994) for DOCs using certain substrates due to risks with older engines.
This technology is approved for use with an open crankcase ventilation and no after treatment engines. The following criteria must be met in order for appropriately retrofitted engines to achieve the aforementioned emission reductions:
- Pre-installation and post installation inspections are to be performed to insure correct functioning of the installed CCV. The CCV filter indicator must be used to access blow-by rates are satisfactory. The pre and post installation inspections must be documented for each vehicle.
- The filtered oil from the CCV must be returned back to the engine oil sump. There is no catch bottle to be used with the CCV system.
- The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.
- The engine exhaust temperature must achieve at least 150 °C during its duty cycle.
- The engine must be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel.
- The engine must not have been originally certified or equipped with a DOC or diesel particulate filter.
- The 4500 and 6000 model filter cartridges must be replaced every 750 engine hours or every other oil change or when indicated by red filter service indicator, whichever occurs first. The 3500 and 3550 model filter cartridges must be replaced every oil change or when indicated by the red service indicator, whichever occurs first.
| Technology | Engine Model/Application |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) † | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
Purifilter, passive regenerating diesel particulate filter |
Highway, Heavy Heavy-Duty, Medium Heavy-Duty; Urban Bus; 4 cycle; model years 1994 - 2003; turbocharged or naturally aspirated; non-EGR engines | 15 | 90 | n/a | 85 | 75 |
† - Baseline assumes an unmodified engine running on regular 2D (<500 ppm sulfur) fuel.
The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:
- The engine exhaust temperature must be at least 280° C for at least 25% of the applicable duty cycle. (As there may be significant variations from application to application, CDTi will review actual vehicle operating conditions and perform temperature data-logging prior to retrofitting a vehicle with their PM filter system to ensure compatibility.)
- The engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- CDTi installs a back-pressure monitor and malfunction indicator light on all vehicles equipped with a Purifilter.
- The engine must be operated with a fuel that contains a sulfur content of no more than 15 ppm to achieve the reductions listed above.
| Technology | Engine Model/Application |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) † | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| Purifilter Plus (Diesel particulate filter on the engine, electrical panel for active regeneration at the garage/maintenance yard) | Highway; heavy, medium, and light heavy-duty; Urban Bus; 4 cycle; model years 1994 - 2006; turbocharged or naturally aspirated; non-EGR engines | 15 | 90 | n/a | 85 | 75 |
† - Baseline assumes an unmodified engine running on fuel with less than 15 ppm sulfur.
The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:
- As there may be variations from application to application, data-logging and a review of actual vehicle operating conditions is required to ensure Purifilter Plus compatibility. CDTi will provide a recommended schedule for active regeneration of the device.
- In most applications, the Purifilter Plus must be periodically actively regenerated with the off-board regeneration control panel. The frequency of active regeneration will vary based on vehicle use or other conditions.
- The engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer. Lubricating oil may not be mixed with engine fuel with this technology.
- CDTi installs the Back-Pressure Monitor and Logger unit and the Remote Driver Display on all vehicles equipped with a Purifilter Plus.
- The engine must be operated with a fuel that contains a sulfur content of no more than 15 parts per million (ppm).
| Technology | Engine Model/Application |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) † | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| Purifilter Plus M (diesel particulate filter on the engine, electrical panel for active regeneration at the garage/maintenance yard) | Highway; light, medium, and heavy heavy-duty EGR and non-EGR engines, not originally certified or equipped with DPF, originally manufactured from 1994-2010 and listed in Table A | 15 | 90 | n/a | 30 | 75 |
† - Baseline assumes an unmodified engine running on fuel with 15 ppm sulfur or less.
The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:
- As there may be variations from application to application, data-logging and a review of actual vehicle operating conditions is required to ensure Purifilter Plus M compatibility. The installer must provide the fleet owner and/or operators with a copy of the pre- and post-installation checklists, as well as copies of the data logging results and recommended regeneration schedules. Fleet owners/operators are responsible for adhering to the recommended regeneration schedule. At a minimum, CDTi recommends that all fleets proactively regenerate the Purifilter Plus M every four to six weeks.
- The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.
- The engine must be in proper operating condition, well maintained, and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel.
- CDTi installs the Back-Pressure Monitor and Logger unit and the Remote Driver Display on all vehicles equipped with a Purifilter Plus M.
| Technology | Engine Model/Application |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) † | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| AZ Purimuffler Diesel Oxidation Catalyst | Highway Medium Heavy-duty, 4- cycle, model years 1991 - 2003 Cummins and Navistar/International engines originally manufactured without any after-treatment which are turbocharged or naturally aspirated, non-EGR engines‡ | 30 | 40 | n/a | 70 | 40 |
† - Baseline assumes an unmodified engine running on fuel with less than 500 ppm sulfur.
‡ - See a list of applicable engines 
on the California Air Resources Board web site.
The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:
- The engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- The engine must be operated with a fuel that contains a sulfur content of no more than 30 ppm maximum sulfur content to achieve the reductions listed above.
| Technology | Engine Model/Application |
Retrofit Fuel, Max Sulfur (ppm) | Reductions (%) † | |||
|---|---|---|---|---|---|---|
| PM | NOx | HC | CO | |||
| AZ Purimuffler Diesel Oxidation Catalyst with CDTi closed crankcase ventilation (CCV) system | Highway, light heavy-duty or medium heavy-duty, 4 cycle, mechanically or electronically injected, turbocharged or naturally aspirated, originally manufactured from 1991 through 2004 model years which meet a 5 or 4 g/bhp-hr NOx standard with no after treatment and open crankcase ventilation engines | 30 | 40a | n/a | 75 | 60 |
† - Baseline assumes an unmodified engine running on fuel with sulfur content of 30 ppm or less.
a - Total PM reduction figures reflect reductions from both tailpipe and crankcase emissions.
The following operating criteria must be met in order for appropriately retrofitted engines to achieve the above emissions reductions:
- The engine should be well maintained and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
- The engine must be operated with a fuel that contains a sulfur content of no more than 30 ppm maximum sulfur content to achieve the reductions listed above.
- The engine exhaust temperature must be at least 150° C during the duty cycle.
- The 4500 and 6000 model filter cartridges must be replaced every 750 engine hours or every other oil change or when indicated by red filter service indicator, which ever occurs first. The 3500 and 3550 model filter cartridges must be replaced every oil change or when indicated by the red service indicator, whichever occurs first.