Kenneth J. Baron

BIOMECHANICAL ANALYSIS OF INDY RACE CAR CRASHES

This paper describes the results of an ongoing project in the GM Motorsports Safety Technology Research Program (MSTRP) to investigate lndianapolis-type (Indy car) race car crashes using an on-board impact recorder as the primary data collection tool. The paper discusses the development of specifications for the impact-recording device, the selection of the specific recorder, and its implementation on a routine basis in Indy car racing. The results from incidents that produced significant data during the racing seasons from 1993 through the first half of 1998 are summarized. Examples of impact recordings are given which are remarkable in terms of the severity of crashes and, in most cases, the resulting lack of significant injuries. A total of 202 cases with peak decelerations above 20 G are summarized. The mean peak rigid body chassis decelerations for the sample were on the order of 53 G. Peak decelerations in excess of 60 G (some as high as 127 G) have been recorded for significant durations in many frontal, side, and rear impacts. Associated mean total velocity change was 28.3 mph for the sample. The relatively tight coupling of the drivers torso to the chassis allows direct inferences of the loads on the torso, particularly in side impacts. The data calls into question the use of chest acceleration as an injury assessment criterion in both frontal and side impacts. For the covering abstract of the conference see IRRD E201429.

Phosphorus accumulation in automotive catalysts

Abstract Steady-state, accelerated phosphorus accumulation experiments were conducted using a multistage integral reactor which was mounted on an engine dynamometer system. Electron microprobe studies showed that the phosphorus accumulation process is controlled by pore diffusion and that the phosphorus tends to form a monolayer over the pore surfaces of the poisoned band in the catalyst pellets. Excellent agreement was found between the experimental results and a progressive shell-type poison accumulation model.

Lead, sulfur and phosphorus interactions with platinum and palladium metal foils

This paper describes the chemical interactions at the active metal surface of platinum and palladium oxidation catalysts subjected to lead, phosphorus and sulfur contaminants. A method of probing the chemical environment of the supported metal surface in catalysts has been developed using Auger electron spectroscopy (AES). The poisoning of Pt and Pd is seen as an accumulation dependent process. The noble metal surfaces first saturate with lead without accumulation of sulfur or phosphorus. The initial accumulation of lead on Pd is different than Pt. At low exposures lead is depleted from the Pd surface. It appears that lead is drawn from the surface into the bulk of the oxidized palladium because of the solubility of PbO in PdO. On platinum, however, no such driving force exists and lead depletion is not indicated. Subsequent accumulation on the lead poisoned Pt or Pd consists of oxidized sulfur, phosphorus and lead. Compound identifications on both Pt and Pd were accomplished using peak shift and structure analyses with respect to AES spectra obtained from PbSO4 and Na4P2O7.

Effects of catalyst particle size on multiple steady states

Carbon monoxide oxidation experiments were carried out over Pt-alumina catalyst particles of various sizes. The width of the conversion-temperature hysteresis loop goes through a maximum as the degree of intrapellet diffusion resistances (i.e., catalyst particle size) is varied. No hysteresis was observed over finely powdered catalysts. The above observations are in agreement with the qualitative predictions of diffusion-reaction theory, and provide further evidence to suggest that the steady-state multiplicities observed here were caused by the interactions between reaction and intrapellet diffusion resistances. The hysteresis loop was found to shift along the temperature axis as the pellet size was varied. The hysteresis occurred at the lowest temperature when catalyst particles of an intermediate size were used. Both larger and smaller particles showed multiplicity at higher temperatures. This observation is also consistent with diffusion-reaction theory.

Carbon monoxide oxidation on platinum-lead films

Abstract The influence of lead on CO oxidation depends on the lead-to-platinum surface atomic fraction. Below a value of about 0.20 the activity of the platinum-lead surface remains high. This “tolerance” of platinum to low lead levels could be due to lead strongly bound on platinum sites, which are not involved in CO oxidation. Above a lead surface atomic fraction of 0.2 rapid deactivation occurs. This reactivity behavior corresponds to a rapid decrease in the ability of PtPb films to chemisorb CO above a lead surface atomic fraction of about 0.2. It is suggested that this deactivation involves surface segregation of lead on catalytically active parts of the platinum metal surface.

Effects of poisoning and sintering on the pore structure and diffusive behavior of platinum/alumina catalysts in automotive converters

Abstract Fresh, sintered (heat treated) and lead poisoned spherical Pt Al 2 O 3 pellets were investigated by ultrahigh pressure mercury porosimetry measurements and by hydrogen-nitrogen static counterdiffusion. The relationship between the effective diffusivity of these pellets and their pore structure was analyzed using the random pore diffusivity model. Poisoning and sintering were found to have opposing effects on the diffusivity. These effects may counterbalance each other in catalytic converters during the aging process so that it is possible that no net observable change in the diffusivity of H 2 in N 2 is recorded during diffusivity measurements on samples from these converters. These phenomena are interpreted in terms of the changes in the pore structure of the catalysts during poisoning and sintering.

Scavenger and Lead Poisoning of Automotive Oxidation Catalysts

The deactivation of noble metal oxidation catalysts of lead and halide lead scavengers was studied in engine and laboratory experiments. Lead alone or lead plus scavengers produced a persistent poisoning of the catalyst. Lead poisoning effects were increased by increased catalyst temperatures and fuel lead content. Tests with scavengers only, conducted in an engine previously operated on leaded fuel, showed that lead was transported to the catalyst causing lead poisoning even in the absence of lead in the fuel. These experiments showed that the reversible scavenger inhibition effects could be superimposed on the persistent lead poisoning effects.