| 摘要 |
A preferred combustion chamber configuration for a piston engine includes two intake valves and one exhaust valve. The two identical intake valves and their associated induction system are arranged to promote separation of the two barrel swirl layers as established in the engine cylinder through the two valves. Further included, in a location containing the intake valves, is a large squish area for providing a fast burn rate in spite of spark ignition in just the richer one of the two barrel swirl layers. Such ignition therefore remains reliable and consistent even when no fuel is injected into the intake passage feeding the leaner swirl layer. Also included in the invention is an engine operating strategy which refrains from injecting fuel into the leaner intake passage until a central engine throttle valve is first at least effectively wide open. Drive-by-wire control coordinates the resulting throttled and unthrottled ranges of engine brake torque output.
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