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March 1, 1960 H. L. WELCH ‘ 2,926,647 V ENGINE HOT SPOT HEATING SYSTEM AND METHOD Filed Feb. 1, 1954 . 3 Sheets-Sheet 1 El. £5 INVENTOR. ?a/aZJ Z. WeZe/Q K772177115 ya’ March 1, 1960 H. L. wELcH 2,926,647 v ENGINE HOT SPOT HEATING SYSTEM AND METHOD Filed Feb. 1, 1954 3 Sheets-Sheet 2 g.\ \ \\\ INVENTOR ?arala’ Z. Mé’Zré March 1, 1960 H. |_. WELCH 2,926,647 v ENGINE HOT SPOT HEATING SYSTEM AND METHOD Filed Feb. 1, 1954 3 Sheets-Sheet 3 7 a 22 14 #4 - INVENTOR. I 2,926,647 United States Patent 0 “ice Patented Mar. 1, 1960 1 2 cycle of the other during the overlap period of the intake and exhaust valves of these cylinders and that if this back 2,926,647 pressure wave is completely eliminated or substantially neutralized as by sufficiently delaying it so that it cannot V ENGINE HOT SPOT HEATING SYSTEM adversely affect the intake action of the other cylinder AND METHOD when the heat valve is open, that the peak torque condition Harold L. Welch, Walled Lake, Micl1., assignor to Chrys may be improved and greater power may be obtained in ler Corporation, Highland Park, Mich., a corporation operation of the engine. of Delaware I have discovered that the latter improvement may be 10 conveniently effected by connecting the crossover passage Application February 1, 1954, Serial No. 407,476 of the hot spot with the exhaust port of a single cylinder 13 Claims. (Cl. 123-122) of each bank which cylinders do not follow each other in the ?ring order. Preferably, they are ports of cylinders which are spaced apart in the (?ring order by at least two This invention relates to methods and structures for 15 other cylinders. Stated in reference to a V-8 engine utiliz effecting heating of the intake manifold hot spot of engines ing a 90° two-plane crank, they are preferably cylinders having opposite banks of cylinders for instance, V-type whose exhaust strokes are 270° of crank rotation out of engines, and especially to such methods and structures phase with each other. The only way that an exhaust which facilitate improvement in the torque and power pressure wave from one of these interconnected cylinders output. 20 can reach the other is by travelling around over a long In typical V-8 engines currently used, an intake mani path through the exhaust manifold and exhaust conduits. fold is positioned intermediate the V-arranged banks of This delays the wave sufficiently in reaching the other cylinders and an exhaust manifold is provided on the out ‘cylinder so that it cannot adversely affect the intake action side of each cylinder bank connecting with each exhaust thereof. It may be observed that the improvement in port of the bank to which it is secured. In such engines 25 engine output effected by utilizing this feature is much it has been common practice to interconnect the exhaust greater than that possible when only a single exhaust port ports of the two middle cylinders of each bank and to in of each bank is interconnected and are of cylinders follow terconnect these pairs of exhaust ports by cross passages ing each other in the ?ring order. in the heads and the intake manifold respectively, the I have also discovered that the peak engine torque may latter passing through the intake manifold hot spot. It 30 to some extent be improved in any of the aforesaid ar is further customary to make exhaust pipe or conduit con rangements by making symmetrical conduit connections nections with one exhaust manifold at approximately the to the exhaust manifold of the two banks of cylinders. lengthwise center thereof and a second exhaust pipe or Experimentation has shown that when one bank has a conduit connection at the end of the exhaust manifold of central connection and the other an end connection it the other bank, rearwardly of the engine, these conduits 35 adversely affects engine torque. being in turn connected with each other by a cross pipe It is therefore an object of my invention to provide in and with the mu?ler. Moreover, a themostatic valve has an engine having opposite banks of cylinders, an intake conventionally been located in the exhaust manifold or manifold hot spot providing su?icient heat during the pipe of one bank. When this valve is closed, as during engine warming up operation which gives a minimum heat engine warm-up, it forces the exhaust gases from that bank effect after the heat control valve is open and the engine through the cross passages aforesaid past the hot spot of is up to normal temperature and to effect this by connect the intake manifold. When the valve is open, as when ing the hot spot with a single exhaust port of each bank the engine comes up to normal operating temperature, of cylinders. ‘ this forced movement is relieved and the natural pulsa Another object of my invention is to substantially at tions of the exhaust system move exhaust gases past the 45 tain the foregoing object while simultaneously substan hot spot and heat the same. tially eliminating or neutralizing the back. pressure effect It is normally desirable to provide maximum heat in of the exhaust waves of the exhaust event of one cylinder the operation of the intake manifold hot spot during on the intake event of another due to the hot spot cross warm~up of a cold engine. However, I have found that over connection between the exhaust ports of such cylinder after the engine is up to its normal temperature, such high banks, this by interconnecting the exhaust ports of only heat at the hot spot is not necessary but in fact is believed cylinders which do not succeed each other in the ?ring detrimental. Thus the conventional hot spot arrange order and which preferably are spaced apart in the ?ring ment that permits such a high heat condition after warm order by at least two other cylinders. up is conducive to a loss in available peak torque in the Another object of my invention is to effect improve engine operation. A minimum torque loss results if the 55 ment in the peak engine torque of a V engine having a exhaust connections to the hot spot are such as to provide hot spot crossover incorporating any of the foregoing fea good heat for engine warm-up but a minimum heat e?ect tures, by providing symmetrical connections of the ex after the engine is up to temperature. To attain these haust pipes or conduits with the exhaust manifolds of the ends I found it best to connect the crossover passage of opposite banks of cylinders. 60 These and other objects and advantages of my inven the hot spot with a single exhaust port of each bank of tion will be apparent from the following speci?cation and cylinders. These can be ports of cylinders having any from the drawings wherein similar numerals designate position in the ?ring order but for reasons which hereafter similar parts of the structure. appear are preferably those of cylinders which do not im In the drawings: mediately succeed each other in the ?ring order. 65 Figure 1 is a transverse section of a V-type internal I have further discovered that in the conventional hot combustion engine to which my invention is applied and spot arrangement utilizing the exhaust ports of two cylin showing the hot spot of the intake manifold system in a ders of each bank of the engine or even where only two crossover passage connecting with the exhaust system of exhaust ports are cross connected but in either case are the engine; of cylinders which follow each other in the ?ring order 70 Figure 2 is a top plan view partly in section of the that the back pressure or exhaust wave of the exhaust intake and exhaust manifold systems of an engine, such event-of oneofvthese cylinders interferes with ‘the intake‘ 7 as shown in Figure 1, incorporating my invention; 2,926,647 3 4 Figure 3 is a schematic view of an engine incorporating may be used with the crank of Figure 6 and ?ring orders one of the features of my invention; Figures 4 and 5 are schematic views of engines incor porating a plurality of features of my invention; and Figures 6 and 7 are schematic views of two suggested two-plane 90° crank pin arrangements for a ‘.1 engine utilizing my invention, the Roman numerals in the ?gures indicating the positioning of the crank throws counting from the front or fan end of the engine and the numerals in the parentheses indicating cylinder members whose 10 pistons are connected with the crank throws. For the purposes of illustration, my invention will be may be used with the crank arrangement of Figure 7. described relative to a 90° V-8 engine of current manu In Figures 2, 3, 4, and 5 my invention has been shown facture having a so-called two-plane 90° crankshaft, as applied to an engine having a crank arrangement of hemispherical combustion chambers and provided with Figures 6 and ?ring orders of 1—8—7—3-6—5—4—2 for downdraft carburetion of the dual type, each riser of Figure 3, 1—8—4—3—6—5—7-2 for Figures 2 and 4, and which is arranged to feed a pair of inner cylinders of one l—5—7—2—6—8-4—3 for Figure 5, as will hereafter be bank and a pair of outer or end cylinders of the opposite more evident.

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