Spontaneous intake type internal combustion engine for vehicles

Abstract

An internal combustion engine (E) of natural aspiration system for a vehicle operates on the Miller cycle in an operating range covering a no-load operating range and a high-load high-speed operating range at a low fuel consumption rate. The internal combustion engine E has simple, lightweight construction, is capable of being manufactured at a high productivity at a low cost. The internal combustion engine E includes a cylinder (2) provided with a cylinder bore (2a), a piston (8) fitted for reciprocation in the cylinder bore (2a), an inlet valve (35) to be opened and closed at a fixed inlet valve opening point and a fixed inlet valve closing point in the entire operating range covering a no-load operating range and a high-load high-speed operating range, and an exhaust valve (36) to be opened and closed at a fixed exhaust valve opening point and a fixed exhaust valve closing point in the entire operating range. The fixed inlet valve closing point is either a point before the bottom dead center or a point after the bottom dead center, at which intake air sucked into the cylinder (2) reverses through the inlet valve (35), and the internal combustion engine (E) has a set piston displacement which enables the internal combustion engine (E) to generate a maximum required indicated power when the inlet valve (35) is closed at the fixed inlet valve closing point in the high-load high-speed operating range.

Description

technical field [0001] The invention relates to a naturally aspirated internal combustion engine for vehicles operating in the form of a Miller cycle. Background technique [0002] As we all know, in previous reciprocating internal combustion engines, the closing time of the suction valve was set before the bottom dead center, or at the bottom dead point where the suction gas that had just flowed into the cylinder flowed back from the open suction valve to the bottom dead point of the suction hole. After the point, the internal combustion engine operates in the form of the so-called Miller cycle. This kind of internal combustion engine operating in the form of Miller cycle, compared with the internal combustion engine operating in the form of Otto cycle, reduces the compression pressure at the top dead center of the compression stroke (actual compression ratio). The form of the Torr cycle is the same, so, for the actual compression ratio mentioned above, the expansion ratio...

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Problems solved by technology

[0004] However, the disadvantages of the above-mentioned prior art are that since a supercharging device or a phase angle variable device must be provided, the structure of the internal combustion engine becomes complicated, the number of parts increases, and the cost and weight of the internal combustion engine also increase. up

In addition, unfortunately, in the prior art disclosed in the above publication, since the internal combustion engine operates in the form of Otto cycle at high load, the improvement of fuel consumption rate through the Miller cycle is not complete.

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