Search Results

PREIGNITION is defined by Mr. Winch as the initiation of a flame front by some means other than the spark discharge at some point in the combustion chamber prior to the arrival of the normal flameat that point. He believes that wild ping is actually a combination of preignition and knock. His study of both 1952 and 1953 cars indicates that preignition has become a very serious problem. Moreover, in some cases, the problem was found to be more serious in the 1953 car of a particular make than in the 1952 model. In these studies preignition and wild ping were identified by a technique that makes use of the spark plug as an ionization gap.

ENDURANCE limits and load losses at various temperatures from -75 F to 650 F for several spring materials are reported in this paper. The materials tested were in the form of helical springs, both shot peened and unpeened. Some general observations made by the authors include: 1. Shot-peened springs had higher endurance limits and greater relaxation than unpeened springs at -75 F and 75 F. 2. As test temperatures rose above atmospheric, endurance limit of all unpeened springs tended to hold steady or increase somewhat, while that of shot-peened springs tended to decrease. 3. Except for high-speed steel and stainless steel, chrome-silicon steel showed lowest load loss in both static and dynamic tests in the temperature range from atmospheric to 450 F. 4. Both unpeened and shot-peened high-speed-steel springs showed high endurance limits at all test temperatures. 5. Endurance limits at -75 F were similar to those at atmospheric temperature, but the amount of set was less, on the average.

SEVERAL 2-stroke-cycle diesel engines of European manufacture are described in this paper. The 2-stroke-cycle diesel was late to appear in the automotive scene in Europe, but noteworthy developments have taken place recently, according to the authors. In England, a couple of successful uniflow engines were placed on the market, while on the Continent the loop-scavenged engine is receiving most of the attention. The authors feel that this is not a step backward dictated by European poverty, but perhaps a step forward toward compactness and simplicity.