Measuring and testing – Gas analysis – Gas of combustion
Patent
1997-02-10
1998-08-18
Chilcot, Richard
Measuring and testing
Gas analysis
Gas of combustion
60276, 731181, G01M 1500
Patent
active
057959927
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an exhaust gas purification device of an internal combustion engine.
BACKGROUND ART
An exhaust gas purification device, for example, exhaust gas purification catalyst, of an internal combustion engine gradually deteriorates in the course of use. Along with this, its performance in purifying the exhaust gas gradually declines. If the performance of purification of the exhaust gas declines, air pollution is caused. Therefore, to suppress air pollution when a vehicle is used for a long period of time, it is necessary to determine to what extent the purification performance has declined. Accordingly, in the past, durability tests have been conducted wherein the vehicle is driven on a vehicle chassis dynamometer by a driving pattern representative of the market driving of the vehicle until the driving distance reaches a target driving distance required for example in emission controls (for example see Japanese Unexamined Patent Publication (Kokai) No. 57-160042). The performance in purification of exhaust gas is measured at the point of time when such a durability test is completed.
Recently, however, the target driving distance required in emission controls has become much longer due to tougher air pollution regulations. If the target driving distance required in emission controls becomes longer, the time required for the durability test becomes longer and therefore the problem arises of a longer time required for development of vehicles.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a method of testing the durability of an exhaust gas purification device able to evaluate in a short period of time the exhaust purification performance of a vehicle after market driving over a long period of time.
According to the present invention, there is provided a method of testing the durability of an exhaust gas purification device which creates the same state of deterioration of the exhaust gas purification device as if the vehicle were actually market driven for a predetermined target driving distance or target driving time. The method of testing durability of an exhaust gas purification device provides a reduced period (a shortened deterioration time) for the catalyst to reach about the same degree of deterioration as when the vehicle is market driven for the target driving distance or target driving time. The reduced period is achieved because a stress higher than the stress applied to the market-driven catalyst is applied to the catalyst. The amount of stress is determined from the relationship between the magnitude of stress causing deterioration of the catalyst for exhaust gas purification and a representative value indicative of the degree of deterioration of the catalyst.
Further, according to the present invention, there is provided a method of testing the durability of an exhaust gas purification device which creates, on a bench dynamometer, or chassis dynamometer the same state of deterioration of the exhaust gas purification device as if the vehicle were actually market driven. The method of testing durability of an exhaust gas purification device creates a representative driving pattern indicative of the market driving of the vehicle and obtains a time shortened driving pattern. The time-shortened driving pattern is then applied to the catalyst as a stress higher than the stress applied to the catalyst when driving the vehicle by a representative driving pattern. The result of this application is a degree of deterioration of the catalyst at the time when this time-shortened driving pattern is completed which is substantially the same as the degree of deterioration of the catalyst by the representative driving pattern. The amount of stress applied in the method according to the invention is determined from the relationship between the magnitude of stress causing deterioration of the catalyst for exhaust gas purification and a representative value indicative of the degree of deterioration of the catalyst.
BRIEF DESCRIPTION
REFERENCES:
patent: 5526643 (1996-06-01), Mukaihira et al.
patent: 5531069 (1996-07-01), Katasuhiko
patent: 5560200 (1996-10-01), Maus et al.
patent: 5591905 (1997-01-01), Fujimoto et al.
patent: 5622048 (1997-04-01), Aoyama et al.
patent: 5636514 (1997-06-01), Seki
patent: 5649420 (1997-07-01), Mukaihira et al.
Domyo Hiroyuki
Higashi Tsuneo
Hirayama Hiroshi
Matsunaga Shinichi
Sanada Masakatsu
Chilcot Richard
Kabushiki Kaisha Toyota Chuo Kenkyusho
McCall Eric S.
Toyota Jidosha & Kabushiki Kaisha
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