APPENDIX B COMPARISON OF DIESEL AND GASOLINE ENGINE EXHAUST1 The comparison described herein is based upon exhaust gas analysis of two engine types used in urban transit buses-the diesel engine and the gasoline engine. Samples of exhaust gases were collected from diesel and gasoline buses operating at four conditions: idle, steady speed, acceleration, deceleration. The charts compare the average concentrations of carbon monoxides, aldehydes, hydrocarbons found in the undiluted exhaust of the test engines. If exhaust contamination of air is said to be due primarily to the discharge of carbon monoxide, aldehydes, and hydrocarbons, then the charts indicate that the diesel engine contributes less to air pollution than gasoline engines. Chart I Carbon monoxide.-The diesel produced practically no carbon monoxide at idle, on acceleration, or deceleration. This has special significance in congested city operation of buses where engines are required to idle, accelerate, and decelerate for considerable amounts of time. Very little of the typical urban transit speed-time cycle involves "steady speed." The diesel engine offers decidedly less hazard from carbon monoxide than the gasoline engine. Chart II Formaldehyde.-On the average, on acceleration and at steady speed the formaldehyde concentration of the exhaust from the two types of engines is not significantly different. The diesel engine has a decided advantage in this respect at idle and on deceleration. If exhaust odor is due primarily to the presence of aldehydes, then the diesel engine is not exclusive in the emission of an objectionable odor. Unpleasant odor from a diesel engine is normally present only under conditions of cold operation and light load, particularly when the engine is accelerated following prolonged idling. Chart III Hydrocarbons.-The hydrocarbon concentration of diesel exhaust is consistently lower than that of the spark ignition engine. The diesel engine must be considered as a minor contributor to this problem, considering the small quantity of diesel exhaust produced compared with all other sources, and the small quantity of diesel fuel consumed as compared with all other fuels. It has been reported that diesel fuel accounts for only 3 percent of the total motor fuel used in this country. It has also been reported that in New York City, for example, the bus population is approximately three-tenths of 1 percent of the total automotive population. 1 "An Analysis of Diesel Exhaust," General Motors Corp., November 1956. The CHAIRMAN. Do either one of the gentlemen with you wish to comment any further at this point? Mr. FELDMAN. I believe that the presentation covers everything that the industry is concerned with, Mr. Chairman. This industry, however, has been plagued-it has had a history of being plagued by local legislators who have attempted to engineer, by means of the legislation, and it is, therefore, very gun shy. And that is of deep concern to this industry. This has happened in a great many communities. And it is happening in the community in which I reside and operate. The CHAIRMAN. Well, you mentioned inconsistencies in your statement, Mr. Howell. It seems to me like the inconsistency is the position you have taken in view of the statement you have just made, in that you think that there out not to be any Federal approaches to the problem-that it ought to be left primarily to the localities. Therefore, why would you not want to make it a Federal problem, so that you could work out an across-the-board program? Mr. FELDMAN. This industry is in favor of the Federal legislation which provides for local regulations. The CHAIRMAN. In other words, you are in favor of Federal regulation that would provide local legislation to further plague you, is that it? Mr. FELDMAN. No, sir. This industry would be in favor of Federal legislation which would lay out guidelines-intelligent, technically feasible guidelines, so that local legislation could be provided. The CHAIRMAN. Well, I think that so far as enforcement and inspection and things of that kind are concerned the local, State community could more appropriately assume that responsibility. I do not know how you would work it out otherwise to carry out this tremendous responsibility, that is growing day by day and year by year. As the urban population increases, the demands for bus service are greater and more people have to be served. Maybe they can decentralize some of the population and get some of it to move out into the rural areas of the country, but as of today, everybody seems to want to concentrate in urban areas. If we could decentralize some of it, the problem might not be so bad, but sooner or later it will be, as the population increases up to the year 2000. I do not know. It has become a problem. That is the reason that we should not ignore it at this time, but I can not see how you can decentralize this thing and leave it all to the localities if you are going to have these vehicles coming from all over the country. I know that you operate in the urban areas. You are engaged in that business. Your buses, primarily, are going to be maintained at a given community point. We cannot, however, cover individual bus situations, but this whole thing, as one of my colleagues said a while ago, is one that will have to be attacked from the Federal level. That is where it will have to come from. It cannot come from a city like Philadelphia or Eldorado, Ark. Are there any questions, Mr. Satterfield? Mr. SATTERFIELD. I have no questions. Mr. CARTER. No questions. |