| 摘要 |
An internal combustion engine has two cylinders (12, 14) interconnected at their head ends by a combustion chamber (20) which contains a catalyst (22). The cylinders have respective pistons (16, 18) reciprocable towards and way from the combustion chamber (20) and arranged to perform together the induction, compression, expansion and exhaust strokes. Air only or the like is freely inducted into one cylinder (12) while fuel or a fuel/air mixture is metered and inducted into the other cylinder (14) during the induction stroke. The catalyst is of a type which effects a chemical reaction to initiate combustion at a relatively low temperature so that when the fuel/air mix contacts the catalyst at the required temperature ignition takes place. The crank shaft angular phase difference between the pistons (16, 18) is controlled during operation so that the air in the first cylinder (12) is at a higher pressure than the fuel or fuel/air mixture in the other cylinder (14) during compression strokes and is forced through the catalyst, preventing contact of the fuel or fuel/air mixture in the second cylinder (14) with the catalyst until ignition is required when the first piston is in the vicinity of its top dead center. Since it is the movement of the pistons themselves which control the ignition timing the latter is not dependent on the timed induction of the fuel and an external ignition circuit is also not required.
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