US1217151A - Arrangement for improving the working of eight-cylinder two-cycle internal-combustion engines. - Google Patents

Description

G. E. CANHAC. ARRANGEMENT FOR IMPROVING THE WORKING or EIGHT CYLINDER TWO-CYCLE INTERNAL COMBUSTION ENmNEs.

APPLlCATION FILED MAR. 30. 1916.

V Patented Feb. 27;1917.

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GEORGES EUGENE CANHAG, OF ST.-DENIS, FRANCE AssIGNoR T0 SOCIETE ANONYME DES ETABLISSEMENTS;

ARRANGEMENT FOR IMPROVING THE WORKING OF EIGHT-CYLINDER INTERNAL-COMBUSTION ENGINES.

Application filed March 30, 1916. Serial No. 87,775.

To all whom it may concern Be it known that I, Gnoncns EUGENE CAN- HAG, engineer, of Rue de lErmitage, at St.-

Lenis, Department of the Seine, France,-

citizen of the French Republic, have invented certain new; and useful Improvements in Arrangements for Improving the Working of Eight-Cylinder Two-Cycle Internal-Combustion Engines; and I do hereby declare the following to be a full, clear, and exact description of the inventlon, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to engines working onthe two-stroke cycle and having four, six or eight cylinders. The crank angles that give the best results from the point of view of uniformity of torque and of the balancing of the engine are known. The application to, two-stroke-cycle motors of rules based on four-stroke-cycle motors does not enable the increase in the number of working strokes to improve theuniformity of the torque. Furthermore, when the scavenging air of two-cycle motors is supplied by compressors independent of the motorcylinders, new difficulties in balancing arlse and thus complicate the problem. The masses of the compressor-pistons and of their connecting rods are large enough to bring inertia forces into play that cannot be neglected. The inertia forces of the come pressors cannot always be'balanced among themselves, and one is constrained either to combine the balancing of the inertia forces of the pumps with those of the engine, in which case the balance calculations lead to setting the engine cranks at angles that are not the most favorable to uniformity of torque; or else to add moving balance weights, which have the disadvantage of increasing the weight of the motor. Another difficulty peculiar to two-cycle motors with scavenging compressors is the choice of the position of the compressors, which should be such that the passages leading from the pump cylinders to the motor cylinders are as short as possible, so that the loss of pressure in the scavenging air may be very slight. This consideration is particularly important.

Specification of Letters Patent.

DELAUNAY BELLEZJILLE, on ST.-DE1\TIS, FRANCE.

TWO-CYCLE Patented Feb. 27, 1917.

This invention relates to means for overcoming all these difficulties in the case of two-stroke cycle eight-cylinder Diesel engines with two scavenging air compressors and two blast air compressors.

Figure 1 is a diagram illustrating the improved'system ofconstruction.

Fig. 2 is a balance diagram of this motor.

Entirely satisfactory results are obtained if themotor and compressor cylinders are arranged according to the plan shown in Fig. 1, if the motor cranks are keyed at 45 from one another, and if the setting of the engine crank and that of the compressor cranks are appropriately related to one another.

Each scavenging compressor is placed between two groups of two working cylinders. The usual single scavenging collector is replaced by four sections each having a quarter of the length and a quarter of the discharge. The resistance to the motion of the air being proportional to the square of the velocity and to the length of the passage, for scavenging passages of the same'cross section, the arrangement shown in Fig. 1 offers only one-sixty-fourth of the resistance offeged by that where the single collector is use The uniformity of torque is as great as possible, keyed at 45, because the various cylinders produce their turning effort successively and never simultaneously.

' The appropriate combination of the setting of the engine and compressorcranks enables a perfect balanceto be obtained.

The cranks of the motor cylinders M and M are set at 180 from one another. These elements being exactly alike, their inertia forces balance, and no inertia moment remains. Similarly the inertia forces of the motor cylinders M and M M and M M and M the scavenging air compressors B and B and the blast air compressors I, and 1,, balance one another in pairs. The moment of inertia of the two cylinders M, and M is positive and reaches a maximum when one of its cranks, (that of M for example) is at its upper dead center. It remains positive until the piston of M reaches the middle of its stroke. Then it becomes negative,

on account of the cranks being reaches its minimum when the piston 01 M is at its lower dead center, remains negative until the piston passes the mid-point 0t its stroke, then becomes positive, and again reaches its maximum when the piston is at its upper dead center. In other words the moment of inertia may be represented by a revolving vector that remains constantly parallel to the cranks M and M the direction of the arm of the crank M being reckoned positive. The moment of inertia of each group of cylinders M and M M and M M, and M may similarly be represented by the projections of revolving vector. All these vectors are equal to one another, because the motor elements are all of the same weight, and the distances between the aXes in each group of two cylinders are the same. The moments of inertia of the compressor elements B and B L and I, can also be represented by revolving vectors, but the latter are not equal either to one another or to the vectors of the motor elements.

It is thus possible to draw the diagram shown in Fig. 5, in which M M M represent the simultaneouspositions of the eight crank pins. 0M 0M 0M Ohli, are the four vectors representing the moments of inertia of the motor elements. OM, and have a resultant along OR, and 0M and OM have a resultant along OR". lhe two resistances OR and OR themselves have a resultant OE. All the moments of inertia of the motor elements lead therefore to a moment which is not much greater than the moment of two adjacent elements set at 180, which can be balanced by means of the compressor elements. The two scavenging air compressors should be set so that their crank pins are at B and B in the straight line OR. These elements are in practice lighter than the motor elements, but the distance between the two compressors is greater than that between two adjacent engine cylinders, and their moment of inertia is a little greater than OR. Most of this difference can be compensated for by means of the moment of inertia of the blast air compressors, by placing their crank pins at 1 Copies of this patent may be and 1,. The slight ditlerence'that remains can be corrected by supplementary masses, but in general this correction is superfluous.

Other positions of the cranks enable the same balance to be obtained. M and M, can be replaced by M and M respectively, and inversely, without changing the moment 01": inertia diagram, but M cannot be substituted for M and inversely. All the crank angles that produce balance are such that the odd motor cylinders are set at 22 30 and 112 30 before or behind the crank of the first scavenging air compressor.

Claims:

1. A two-stroke cycle engine of the Diesel t )e consist-in of ei ht workin 0 linders 7 b 7 two scavenging air compressors and two blast air compressors, the cylinders being grouped so that four of the working cylinders are located adjacent to a compressor cylinder and the other four are located at a distance from a compressor not exceeding the width of a cylinder.

2. A two-stroke cycle engine of the Diesel type, consisting of: eight working cylinders, two scavenging air compressors, two blast air compressors, a. piston in each of the cylinders and in each of the compressors, a crank-shaft and a piston-rod connected to each piston and to the shaft, the eight driving cranks being set at from one another and the four compressor cranks being set in a plane that bisects one of the dihedral angles of e5 formed by the planes containing the driving cranks, the cranks of the two scavenging air compressors being opposite to one another and also those of the blast air compressors, the odd driving cranks being set at 22 30 or 112 30 before or behind the crank of the first scavenging air compressor, and each even driving crank being opposite to the immediately preceding odd crank. I

In testimony whereof I afiix my signature, in presence of two witnesses.

motions EUGENE GANHAG. Vfitnesses (inns. P. PRnssLnY,

HENRI COHEN.

obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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