A reputable engine company makes spark-ignition engines that operate with a = 1.0 and a compression ratio of 9:1 for years. In order to control emissions, the engines operate with 20% exhaust gas recirculation (EGR). Since the company's market share is steadily dropping, they hire a young engineer, who was working for a year in an automotive company, to rescue them. The ambitious young engineer proposes a novel design which operates lean ( = 0.8), without EGR, with a high compression ratio (15:1) and vigorous inlet swirl. The new engine has the spark-plug mounted at the center of the combustion chamber, while the production engine has the spark plug at the side. (a) Will the ignition delay of the new chamber be shorter, longer, or about the same as the current design? (b) Will the rate of combustion of the new chamber be faster, slower, or about the same as the current design? (c) Sketch the mass fraction burned versus crank-angle curves for these two combustion chambers when spark timing is set for maximum brake torque. Clearly label the spark timing, ignition delay, and burn duration for each case. (d) The engineer claims that the proposed lean-burn engine will have the same octane requirement as the production SI engine. Could this claim be true? (e) Will the proposed lean-burn engine clearly develop greater brake power at wide-open throttle than the current SI engine? (f) Should the young engineer be promoted or should he get more training?