Alternative Technologies for Studying Catalyst Behaviour to Meet OBD II Requirements

Pelters, Stephan; Schwarzenthal, Dietmar; Maus, Wolfgang; Swars, Helmut; Brück, Rolf

doi:10.4271/932854

Cited by 13 publications

(3 citation statements)

References 6 publications

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“…However, this method is not discussed in this paper. [5] It should also be mentioned that test bench aging processes (by means of misfires, for example,) may involve the risk of mechanically destroying the catalyst's substrate. In the following text, a new oven aging method is presented with the advantage that it can be utilized for any catalyst substrate and that even canned subsystems can be heat treated in the oven.…”

Section: These Methods Includementioning

confidence: 99%

New Catalyst Preparation Procedure for OBDII-Monitoring Requirements

Schmidt

Brady

Summers

et al. 2001

SAE Technical Paper Series

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In order to match catalyst OBDII conditions the common procedure is oven aging with air, which is not suitable for complete converter systems due to mantle corrosion. The goal was, therefore, to find an alternative procedure to ensure a defined catalyst aging that would match 1,75 times the emission standard and is also good for SULEV. The new procedure currently being developed allows the aging of metal and ceramic catalysts as well as complete catalyst systems. The paper will present the aging process, emission data of fresh and aged catalysts and the feedback to the test car OBDII system.

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Section: These Methods Includementioning

confidence: 99%

New Catalyst Preparation Procedure for OBDII-Monitoring Requirements

Schmidt

Brady

Summers

et al. 2001

SAE Technical Paper Series

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“…The alternative approach to oxygen sensors for catalyst efficiency monitoring is the use of thermocouples (10,11). The operating principle of this system is to measure the temperature rise within the catalyst due to the heat generated by the oxidation of the CO and HC.…”

Section: Introductionmentioning

confidence: 99%

“…Reference (10) describes how temperature differences between catalyst outlet and inlet were measured under low idle engine speed (, 1000 r=min). It was found that at steady state this temperature difference reached 30±35 8C for a new catalyst and 25 8C for an old one.…”

Section: Introductionmentioning

confidence: 99%

Three-way catalyst assessment via outlet—inlet temperature measurements: Driving tests

Sparis

Botsaris

Karkanis

et al. 1997

Proceedings of the Institution of Mechanical Engineers, Part D:

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This paper presents and discusses experimental data obtained during driving tests simulating the test cycle, ECE 15, and relates exhaust gas levels of hydrocarbon (HC) and carbon monoxide (CO) to catalyst outlet±inlet temperature differences. It also presents the preliminary results from the operation of a microcontrolled on-board diagnostics (OBD) II catalyst efficiency assessment system based on a statistical analysis of the catalyst outlet±inlet temperature difference thermocouple signal. There are indications that this system performs satisfactorily after an adequate warm-up period, if a sampling period in the order of 300±400 s is allowed.Although this operating principle is supported by considerable experimental evidence, there are several technical problems that must be overcome before it can comply to the OBD II requirements. Firstly, as engine loads increase, the efficiency of all catalysts tested is improved considerably by the high exhaust gas temperatures. Furthermore, as the catalyst outlet±inlet temperature difference tends to decrease, so does the sensitivity of the measurements. During driving, catalyst outlet±inlet temperature differences could also be affected by other external factors such as the car speed, rain or snow etc., or long-term temperature sensor drift. Present results indicate that catalyst outlet±inlet temperature difference is also influenced by the ambient temperature. A preliminary analysis of the data indicates that a linear relationship may exist between these two quantities, however, more tests are required for a statistical proof of this assertion.In spite of these problems, the results presented here tend to support the idea that a catalyst performance assessment system using temperature probes is technically feasible. However, further tests are required under various engine operating conditions and environments before a final conclusion can be drawn.

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Catalytic automotive exhaust aftertreatment

Koltsakis

1997

Progress in Energy and Combustion Science

310

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Alternative Technologies for Studying Catalyst Behaviour to Meet OBD II Requirements

Cited by 13 publications

References 6 publications

New Catalyst Preparation Procedure for OBDII-Monitoring Requirements

New Catalyst Preparation Procedure for OBDII-Monitoring Requirements

Three-way catalyst assessment via outlet—inlet temperature measurements: Driving tests

Catalytic automotive exhaust aftertreatment

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