Various government agencies such as EPA and CARB have established evaporative emission standards for light duty vehicles. To help the OEM's meet these emission standards for volatile organic compounds (VOC's), Honeywell has developed a hydrocarbon adsorber (HCA) approach to reduce hot soak emissions that escape through the air induction system. The HCA has a small footprint and is incorporated in the air filter housing while having a minimal impact on the air flow to the engine during normal operation. As required through EPA regulations it is permanently mounted to provide life of the vehicle durability.
In this paper, the process for selecting the VOC adsorbent that functions within the parameters of the hot soak cycle and is regenerated under standard engine operation is discussed. An important part of this technology has been the development of a laboratory test that would simulate engine conditions and permit evaluation of various HCA prototypes. The rationale for this laboratory test will be presented. This laboratory test and applicable data have been used to compare HCA configurations and to support design decisions.
Further discussion will be presented on a developed validation test system that utilizes the vehicle's production air filter housing with an HCA. This test simulates the hydrocarbon loading during engine shut-off and subsequent fresh air purge during engine operation.
This hydrocarbon adsorption system has been developed and optimized to perform in a wide variety of induction housings, including both clean and dirty side applications. The mounting systems include post mount (heat stake) and flush mounting using an adhesive. Data have been generated to show the performance of the Honeywell HCA in over 20 systems using Honeywell's lab test. Several HCA's have been validated and are currently in production.