Internal-combustion engines – Multiple cylinder – Cylinders in-line
Patent
1987-06-09
1988-11-01
Myhre, Charles J.
Internal-combustion engines
Multiple cylinder
Cylinders in-line
123 65S, F02B 7520
Patent
active
047811536
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION OF INVENTION
This invention relates to an internal combustion engine and more particularly, to an internal combustion engine of the kind hereinafter referred to as "of the kind speciifed" having at least one pair of cylinders each containing a stepped piston, each cylinder and piston having a pumping part of larger diameter and a working part of smaller diameter, the working part of each cylinder being charged by precompressed charge (as herein defined) delivered from the pumping part of the other cylinder.
By a "charge" we mean a mixture of air and fuel, or air alone, in which latter case at least fuel would need to be injected or otherwise introduced into the working part of each cylinder by further means.
In an engine of the kind specified, a transfer path, which may have one or more branches, extends from the pumping part of one cylinder to the working part of the other cylinder. In known engines of the kind specified, there are two ways of providing such a transfer path.
First, the transfer path is provided by a passage in the crank case casting which passage comprises a first passage part which extends generally parallel to the axis of movement of the piston from the pumping part of one cylinder, to a second passage part transverse to said axis which second part opens into the working part of the other cylinder.
Such a transfer path has disadvantages in that (a), providing a casting with such a passage in the crank case, requires a complicated technique involving specialised labour and thus increasing costs, and (b), the charge has to change direction suddenly in order to pass from the first to the second passage part. The second passage part is usually short in length due to the restricted space available in the casting, so that the charge has to change direction immediately before passing into the working part of the cylinder. This can be detrimental to efficient scavenging in an engine of the kind specified.
Secondly, a transfer path is provided using a manifold which is secured to the cylinder block. A first passage part extends from a first position on the interface of the crank case and the manifold, to the pumping part of each cylinder and a second passage part which extends from said first position on the interface, through the manifold, back to the second position on the interface, and a third passage part extends from said second interface position to the working part of the cylinder. Such an arrangement is simpler in construction compared with the first described arrangement as the passage parts each open to the interface. However, at least the manifold, which is usually provided as a casting, requires sand casting and it will be appreciated that the precompressed charge still has to flow along a tortuous transfer path and so this second arrangement suffers from many of the disadvantages of the first described arrangement. Further, it is not readily possible where a manifold is provided, to arrange two pairs of cylinders in a V formation because of restriction in available space.
According, it is an object of the present invention to provide a new or improved internal combustion engine which overcomes or reduces these disadvantages of known arrangements.
According to the invention I provide an internal combustion engine of the kind specified, having a crank case (as herein defined) and at least one cylinder block secured together at an interface, the crank case and the at least one cylinder block together defining the two cylinders in which the stepped pistons are slidable, the pistons each being connected to a crank shaft mounted in the crank case, a transfer path along which said precompressed charge may flow from the pumping part of each cylinder to the working part of the other cylinder, in which the charge is ignited, each transfer path comprising first, second and third passage parts, the first passage part communicating with the pumping part of one cylinder and the second passage part, and the third passage part comprising at least two branches each communicating with t
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patent: 1001485 (1911-08-01), Wells
patent: 1465885 (1923-08-01), Wege
patent: 3301237 (1967-01-01), Wolf
patent: 3550569 (1970-12-01), Hooper
patent: 3641987 (1972-02-01), Hooper
patent: 3731662 (1973-05-01), Fandrich
patent: 4630591 (1986-12-01), Hooper
Myhre Charles J.
Okonsky David A.
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