US2820441A

US2820441A - Design and arrangement of the coolant pump of internal combustion engines

Info

Publication number: US2820441A
Application number: US511727A
Authority: US
Inventors: Scheiterlein Andreas; Skatsche Othmar
Original assignee: Hoval AG
Current assignee: Hoval AG
Priority date: 1954-06-12
Filing date: 1955-05-27
Publication date: 1958-01-21
Anticipated expiration: 1975-01-21

Description

A. SCHEITERLEIN ET'AL 2,820,441

2 DESIGN AND ARRANGEMENT OF THE COOLANT Y. PUMP OF INTERNAL COMBUSTION ENGINES Fil-ed May 27, 1955 2 Sheets-Sheet 1 n-21,1958 A. SCHEITERLEM-FAL 2,820,441

DESIGN "AND ARRANGEMENT OF THE COOLANT PUMP OF INTERNAL COMBUSTION ENGINES Filed May 27, 1955 2 Sheets-Sheet 2 F763 1 IE V I I e I v I] 51 8 5 United States Patent DESIGN AND ARRANGEMENT OF THE COOLANT PUMP OF INTERNAL COMBUSTION ENGINES Andreas Scheiterlein and Othmar Skatsche, Graz, Austria, assignors to Gustav Ospelt, Vaduz, Liechtenstein Application May 27, 1955, Serial No. 511,727 Claims priority, application Austria June 12, 1954 4 Claims. (Cl. 12.3-41.46)

This invention relates to a two-stroke internal combustion engine with vertical cylinders arranged in a row, each cylinder having a piston-controlled exhaust port, and wet cylinder liner, the liner being surrounded by a coolant chamber and a separate coolant chamber surrounding the exhaust passages in the cylinder block. For this type of engine it has been known to arrange the coolant pump on the front side of the cylinder block and to feed the two aforementioned coolant chambers with coolant through separate hose lines. This affords efficient cooling both for the cylinder liners and the exhaust ports in the cylinder block by means of fresh, cooled-down coolant. Since the amount of heat to be extracted from the cylinder liners is considerably larger than for the exhaust passages, the coolant chamber around the cylinder liners will have to receive a correspondingly larger supply of coolant than the coolant chamber around the exhaust passages. Usually the amount of coolant delivered by the coolant pump is predetermined by the use of different passage sections for the hose lines and by providing chokes of appropriate dimensions along the coolant flow.

The disadvantage of the above arrangements resides in the fact that the allocation of supply depends on factors which are liable to dilfer too freely from the proposed values or are subject to alterations in the course of time. Consequently, the uniform cooling of all parts is not positively assured.

According to the invention, these drawbacks are avoided by providing a centrifugal coolant pump with two delivery channels, each of which is assigned to one of the coolant chambers, one of said channels feeding the coolant chamber around the cylinder liners being connected at one end and the other at the other end of the pressure groove of the coolant pump. Thus the pressure head and the delivery of the pump are divided at a fixed predetermined ratio. The distance between the delivery channel leading to the exhaust ports and the other end of the pressure groove will determine the portion of the overall pressure head which is allocated to this delivery channel. Besides, the allocation of deliveries is largely independent of the pipe section used.

According to a further feature of the invention the housing of the coolant pump and the two delivery channels constitute a single casting, the delivery channels being connected to the coolant chambers through the surface of attachment of the coolant pump on the cylinder block. This eliminates the need for hose connections, simplifies installation and increases the safety of operation. In addition since the sections of the delivery channels are determined in advance, it is impossible for the cooling conditions to be adversely affected by the use of hose connections of unsuitable section, as may happen during repairs for instance.

According to further embodiments of the invention, provision has been made for the delivery channels and the coolant pump being drained completely during the discharge of the coolant. This is achieved by appro- 2,820,441 Patented Jan. 21, 1958 The invention is illustrated by way of example in the accompanying drawings wherein:

Figure 1 shows a front view of the two-stroke engine with the coolant pump in section along the line I-I of Figure 2. Figure 2 shows the coolant pump in section along the line II-II of Figure 1 and Figure 3 a partial vertical section through the axis of a cylinder.

The cylinder block of the two-stroke engine is designated by 1, the cylinder liner by 2, the cylinder head by 3, the piston by 4 and the connecting rod by 5. The cylinder liner 2 is inserted in the cylinder block 1 and both together constitute the coolant chamber 6, the lower portion 6' of which is enlarged. It is clamped at the upper end and fixed together with the cylinder head 3 by means of cylinder head screws 7. At other points the cylinder liner is slidable for axial expansion and sealed by means of rubber rings 8. The coolant is delivered into the coolant chamber 6 by the coolant pump 9 through an aperture 10 and the connecting passage 10 in the cylinder block and flows through said chamber 6 and the chamber 6 while cooling the cylinder liner 2, and then passes through passage apertures 11 into the cavity of the cylinder head 3. A nipple 12 is provided on the cylinder head for the discharge of the coolant.

The exhaust ports 13 of the engine are controlled by a piston 4 and lead to discharge channels 14 of the cylinder block and from there into the exhaust manifold 15. The discharge channels 14 in the cylinder block are surrounded by a separate coolant chamber 16, the upper portion of which communicates with the coolant chamber 6 by means of apertures 17. The coolant is delivered into the coolant chamber 16 through a passage aperture 18 located at its lowest point 16'.

The coolant pump 9 consists of a rotor 19 driven in the usual manner (not shown in the drawings) from a V-belt pulley 20 via a shaft 34 by the crankshaft. The pump intake is designated by 21 and the suction chamber by 22. The pressure groove 23 surrounding the rotor 19 communicates at one end with a short delivery channel 23' communicating with the passage aperture 10 in the cylinder block via the surface of attachment 24 of the pump. A second pressure channel 25 is located near other end of the pressure groove and connected to the latter and leads also through the surface of attachment 24 to the passage opening 18 of the cylinder block. The delivery channel 25 is slightly inclined from the outside toward the center of the pump. At its lowest point a small connecting duct 27 has been provided. These measures ensure the complete discharge of the coolant pump and the delivery channels during the draining of the coolant. The bore 27' is required for manufacturing purposes only and otherwise closed. The housing 28 of the coolant pump including the delivery groove 23 and the

delivery channels

23 and 25 are formed by a single casting. The pump is fixed with the interposition of a plate 29 by means of screws inserted in the bores 30.

The scavenging air blower is designated by 31, the starter by 32 and the front cover of the casing by 33.

I claim:

1. In a two-stroke internal combustion engine, the combination comprising a cylinder block having vertical cylinders arranged in a row, with reciprocating pistons, wet cylinder liners surrounded by a coolant chamber, pistoncontrolled exhaust ports, exhaust channels in the cylinder block surrounded by a separate coolant chamber, a coolant pump of the centrifugal type arranged at the front end of the cylinder block, with a pressure groove and two delivery channels, each of which is assigned to one 'ofthe coolant chambers, one of said channels feed ing the coolant chamber around the cylinder liners being connected at oneend of the pressure groove of the coolant pump, whereas the. other channel feeding the coolant chamber surrounding the exhaust passages is connected at the other end of said pressure groove.-

2. The combination according to claim 1. and wherein the housing of said coolant pump and its two delivery channels are formed by a single casting, said delivery channels communicating with said coolant chambers through the surface of attachment of' the coolant pump.

3. The combination according to claim 2 and-wherein ma e;

the delivery channel connected between the other end of the pressure groove is either horizontal or slightly inclined toward the center of the pump, said channel being connected at the lowest point of said pressure groove.

4. The combination according to claim 3 and wherein a small connecting duct is provided at the lowest pointof the delivery channel leading to the suction chamber of the coolant pump.

References Cited in the file of this patent UNITED STATES PATENTS 2,216,802 Baster Oct. 8, 1940