Samet TÜRKMEN-030060143-1st week answers

SI Engine(kind of engine)

             Old: (beter)

              The spark- ignition engine (or SI Engine) is a piston engine with external or internal air-mixture formation. External mixture formation generally produces homogenous mixtures, whereas an internally formed mixture is largely heterogenos at the instant of ignition. The time of the mixture formation is a major factor influencing the degree of homogenization achievable by internal mixture formation. In both cases, the mixture is compressed to approximately 20-30 bar on the compression stroke, to generate a final compression temperature of 400-500C. This is still below teh auto-ignition threshold of the mixture, which then has to be ignited by a spark shorly before te piston reaches TDC.

      (  Bosch automotive handbook,Section;Reciprocating- piston engines with internal   combustion, p.8)

            New:

            A gasoline engine is called a spark ignition engine,with an ingition system creating the spark. Older engines used a distributor, geared to the camshaft to time and distribute the spark to the spark plug at exactly the correct instant.

      ( Gilles T., automotive service, p.214  )