Final Report: Innovative Catalytic NOx Control System for Reducing Mobile Source Cold Start Emissions

EPA Contract Number: 68D99065
Title: Innovative Catalytic NOx Control System for Reducing Mobile Source Cold Start Emissions
Investigators: Roychoudhury, Subir
Small Business: Precision Combustion, Inc.
EPA Contact:
Phase: I
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , SBIR - Air Pollution , Small Business Innovation Research (SBIR)


The program developed high specific-surface-area (SSA) coatings for ultra-short channel length metal Microlith( substrate converters, achieving all stated objectives. The high SSA coating offers improved high-temperature durability and lowered catalyst lightoff temperatures with appropriate oxygen storage properties. This allows improved close coupled performance for meeting more stringent emission standards (e.g. SULEV and ULEV on larger vehicles) and the ability to locate lightoff converters further from the engine as well as reduced size and cost for main converter applications. The reduced precious metal catalyst usage as well as reduced substrate cost results in lower cost for achieving mandated emission standards.

The objective of this Phase I program to demonstrate proof of concept that a durable, high specific-surface-area coating could be developed for the Microlith( catalyst substrate for automotive emissions reduction as well as providing lower lightoff temperature for earlier lightoff after a cold start was successfully achieved. The durable and effective high surface areas were developed through laboratory and automotive testing of samples prepared with varying compositions and processes. Since lightoff is kinetically controlled, an increase in surface area would improve reaction rates and result in lower lightoff temperatures. The additional active surface area would also provide better poisoning resistance in dirtier engines as well as greater reduction in automotive methane emissions. Moreover the new coating developed would allow addition of constituents (e.g. allowing greater oxygen storage) for operation as a main converter for increased potential market size. The Microlith( substrate geometry was optimized for improved durability, better performance, and reduced manufacturing cost. While high surface area coatings for long channel ceramic or metal monoliths are well known in the art, its application to short path length, high cell density Microlith( substrate, with the mechanical durability necessary for automotive use, required substantial innovation.

Summary/Accomplishments (Outputs/Outcomes):

The proposed objectives and results have been summarized in the table below:

Phase 1 Objectives
Phase 1 Results

Develop stable and durable high SSA coatings on Microlith( under automotive exhaust conditions

Successfully demonstrated in standard automotive "hot vibration" engine tests without failure, for duration's and at temperatures higher than required.

Demonstrate performance of the coatings by:

  • Demonstrating washcoat thermal stability
  • Lowering light off temperature (by as much as 100?C)
  • Lowering precious metal usage
  • Demonstrating reduced emissions & backpressure (?P)

These objectives were demonstrated through:

  • Stable surface area after thermal aging
  • Lightoff temperatures reductions from 60-110?C
  • 20% reduction via good catalyst dispersion
  • Earlier lightoff for greater conversion /unit ?P

Develop a predictive model for automotive converter design with Microlith( substrate.
Successfully developed and results confirmed with bench scale and engine data.
Explore technology commercialization through:

  • Engine test opportunities
  • Business discussions & technology marketing.
  • Joint development agreement signed with a major U.S. engine manufacturer.
  • Testing at multiple original equipment manufacturers (OEM's) underway.


The proposed objectives were successfully achieved and proof-of-concept of PCI's novel catalytic substrate and coating were demonstrated. Lightoff temperature reductions ranging from 60 - 105?C were achieved. Mechanical durability of the high surface area coating was successfully demonstrated in hot vibration engine tests and emissions evaluation of prototypes in engines is currently underway.

The project demonstrated the potential of this technology for reducing mobile source emissions (NOx, HC and CO) through early lightoff and without significantly compromising engine performance while being economically attractive and possessing desirable design attributes for vehicle/engine integration.

Supplemental Keywords:

Licensing, manufacturing, joint development with OEM's, additional (option) funding, emissions reduction, automotive and other mobile markets, financing plan., RFA, Scientific Discipline, Air, Toxics, Waste, Sustainable Industry/Business, air toxics, cleaner production/pollution prevention, Chemistry, HAPS, Technology for Sustainable Environment, mobile sources, New/Innovative technologies, Engineering, Engineering, Chemistry, & Physics, Incineration/Combustion, Nitrogen Oxides, automotive coating, Nox, catalyst composition, catalytic oxidation, vehicle emissions, motor vehicle exhaust, novel catalyst systems, automobile combustion, automotive combustion, automotive exhaust, catalysts, auto emissions, combustion, combustion engines, nitrogen oxides (Nox), exhaust, air emissions, coatings