Uillted States Patent [19] [11] Patent Number: 5,315,973 1

' _ US005315973A UIllted States Patent [19] [11] Patent Number: 5,315,973 Hill et al. [45] Date of Patent: May 31, 1994 [54] IN'I'ENSIFIER-INJECI‘OR FOR GASEOUS 4,704,997 11/1987 EndO =1 a1. .................. .. 123/27 GE FUEL FOR POSITIVE DISPLACEMENT 4,742,801 5/1988 Kelgard . .. 123/526 ENGINES 4,831,982 5/1989 Baranescu ...... ..123/300 4,865,001 9/1989 Jensen ....... .. 123/27 GE [75] Inventors: Philip G. Hill, Vancouver; K. Bruce 4,922,862 5/1990 Casacci 123/575 Hodgins, Delta, both or Canada 5,067,467 11/1991 11111 et al. 123/497 , _ _ __ _ 5,136,986 8/1992 Jensen 123/27 GE [73] Ass1gnee= Umvemty 0f Brlhsh Columbm, 5,190,216 3/1993 Deneke ............................. .. 239/434 Van uver, Can 11 co I a a Primary Examiner-Noah P. Kamen [21] APPL No‘ 7974442 Assistant Examiner-Erick Solis [22] Filed: No“ 22, 1991 Attorney, Agent/or Finn-Seed and Berry [57] ABSTRACT Related U's' Apphcahon Data This invention relates to a novel device for compressing [63] Continuation-impart Of Ser- NO- 441,104, NOV. 27, and injecting gaseous fuel from a variable pressure gase 1989, Pat- N0~_5,067,467- ous fuel supply into a fuel receiving apparatus. More [51] I111. 01.5 ................... .. F02M 21/02; FOZM 61/00; particularly, this invention relates to an intensi?er-injec FQZB 3 /00 tor which compresses and injects gaseous fuel from a [52] US. Cl. .................................. .. 123/304; 123/299; Variable Press“re SOurce into the cylinder of a Positive 123/27 GE; 123/525; 239/533_12 displacement engine. An intensi?er-injector for gaseous [58] Field of Search ................ .. 123/27 GE, 575, 299, fuels in internal combustion engines comprising means 123M300’ 304’ 525; 239/533_12 which utilizes the compressed gas from the chamber of the internal combustion engine or compressed ?uid or [56] References Cited gas from an external compressor to drive an intensi?er U,S, PATENT DOCUMENTS means which raises the pressure of fuel gas supplied to the internal combustion engine for rapid late-cycle in jection into the cylinder of the internal combustion, 4,091,772 5/1978 Heater et al. 123/27 GE 81181119 4,ll2,899 9/1978 Kramer ............ .. 239/533.l2 ' 4,546,740 10/1985 Clements et al. ................. .. 123/304 9 Claims, 17 Drawing Sheets l9 \/ 2| _}_ l IO 4 l2 i . Ev :1 l6 l 6 ! 22 26 24 20 20 ‘ Z US. Patent May 31, 1994 Sheet 1 of 17 5,315,973 FIG. I \\\\\\\\\\\\\\\\\\\N\\\\\\5 y B.6 wmmwmw»////////////////////4 //)///)// 2 6 §l/7\w US. Patent May 31, 1994 Sheet 3 of 17 5,315,973 Ad 2 D .l/l... m///6; v. \\\\\\\\\\\\\\\\\\\\k\\ NEW“ / \\\\\\\\\\\\\\> 6 us. Patent May 11, 1991 ‘ $111111 01 17 5,315,973 FIG. 4 US. Patent May 31,1994 Sheet 5 of 17 5,315,973 2| \\\\ / \\\ \\\\\\\\__\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\ 24") 28 U.S. Patent May 31, 1994 Sheet 7 of 17 5,315,973 1 AT\ wv/ \\\\\\\\\\\\\\\\\\\ 6. //% 2a 24 FIG. 7 US. Patent May 31, 1994 Sheet 8 of 17 5,315,973 4 2 4 4 O Pu FIG.‘ 8 US. Patent May 31, 1994 Sheet 11 of 17 5,315,973 y I 11/1 Ow 105.5232‘ F1»... ..wE__ NN US. Patent May 31, 1994 Sheet 12 of 17 5,315,973 57525.2-‘ 1|It B\N711vH1 o_ ///////////éA,7////////...1.._ 3,;Z3i ‘as: {I 525%: v vw 5.5.5233 Q2 III/7 [III/11111111111] QM US. Patent May 31, 1994 sheet 15 of 17 5,315,973 mm_...=wZw._.Z_@N4| GmJ\6.omw+ qQ- . o \ g .@@E9i Q{PM_mmm~_mm .. mm ww N.)E. I. \\\\E mm 9($2523? wNA\\‘ .. ?n. / \\\\\\\\ $7E@m MN, mm \% 5,315,973 1 2 and it is questionable whether at low load the exhaust INTENSIFIER-INJECI‘ OR FOR GASEOUS FUEL heat available would be sufficient. FOR POSITIVE DISPLACEMENT ENGINES Control systems have been devised to vary the die sel/gas proportion as a function of load and speed. To This is a continuation-in-part of application Ser. No. provide acceptable operation these require detailed 07/441,104, ?led Nov. 27, 1989, now US. Pat. No. engine-speci?c performance data banks to be stored 5,067,467. within the computers required for engine control. De FIELD OF THE INVENTION velopment of such a system is costly and must involve compromise between the objectives of low fuel con This invention relates to a novel device for compress 10 sumption, low emissions, engine durability and high fuel ing and injecting gaseous fuel from a variable pressure substitution. ' gaseous fuel supply into a fuel receiving apparatus. Problems encountered with “natural fumigation” More particularly, this invention relates to an intensi? methods are fundamental i.e. not peculiar to one type of er-injector which compresses and injects gaseous fuel combustion chamber. Thus, if emissions, fuel economy from a variable pressure source into the cylinder of a during part load operation, and engine durability are positive displacement engine. each important, premixing the air and gas is not a gener BACKGROUND OF THE INVENTION ally suitable method for dual fueling in diesels. An alternative method, “timed port injection”, has ‘ Because of its ready availability and because of its been proposed for injection of natural gas into two relatively low cost and potential for reducing particu 20 stroke diesel engines. The objective is to time the injec late emissions, compressed natural gas is a promising tion of natural gas into the inlet port so as to avoid candidate for fueling diesel engines. Conventional wasted gas leaving with the exhaust and (ideally) at low methods of fueling diesel engines by premixing air and load to have the gas stratified within the cylinder so that natural gas appear to be inherently unsuitable for part it can burn acceptably after compression and diesel pilot load operation, at which the fuel-air mixture ?ammabil 25 ignition. So far, this method to the applicants’ knowl ity suffers, efficiency drops substantially and emissions edge has not proven capable of high ef?ciency, durable, become excessive. In addition there is the problem of clean operation over a wide range of load and speeds detonation under certain load conditions. These factors and with high levels of fuel substitution. generally impose a limit on the feasible substitution of diesel fuel by natural gas in transport engines operating 30 Direct Injection of Natural Gas into Diesel Engine over a wide range of load and speed. Cylinders Fueling Diesel Engines with Premixed Air and Natural The great advantage of direct injection of fuel into Gas the engine cylinder in diesel operation is that it permits efficient and stable burning over the whole load range. Much work has been done on the “natural fumiga 35 This is because the burning occurs in local regions in ' tion” method of using natural gas in a diesel engine by which the fuel-air ratio is within the ?ammability limits. injecting it into the inlet manifold, with injection into Natural gas has the advantage over diesel fuel in that it the cylinder of small quantities of diesel fuel for “pilot” does not require atomization into (micron-size) droplets diesel ignition. There are three major faults with this and thus does not require very high injection pressures method: and super ?ne tolerances on injector plungers. For die 1) At low load, with unthrottled diesel operation, the sel injection, pressures may need to be as high as 1000 gas fuel and air mixture (which is essentially homogene atm for most efficient operation. It appears that for ous) is too lean for satisfactory combustion and fuel natural gas 200 atm would be satisfactory. efficiency can become unacceptable. A remedy may be Successful operation of large bore diesels with diesel to revert to mainly diesel fuel consumption at part load. 45 injection of compressed natural gas has been demon However, since in many applications most of the opera strated in North America, see J. F. Wakenell, G. B. tion may be at part load, this tends to defeat the funda O’Neal, and Q. A. Baker, “High-Pressure Late Cycle mental objective of fuel substitution. Direct Injection of Natural Gas in a Rail Medium Speed 2) With low efficiency in part load operation, the Diesel Engine”, SAE Technical Paper 872041, in Nor emissions of unburned hydrocarbons and carbon mon way, see Einang, P. M., Korea, 8., Kvamsdal, R., Han oxide will rise far above the acceptable limits. sen, T., and Sarsten, A., "High-Pressure, Digitally Con 3) With successful pilot diesel ignition of natural gas, trolled Injection of Gaseous Fuel in a Diesel Engine, engine pressure loading (both maximum pressure levels with Special Reference to Boil-Off from LNG Tank and incidence of detonation) can be harmful and there is ers”, Proceedings CIMAC Conf., June 1983; and Japan, danger of engine damage. There is typically a band of 55 see Miyake, M., Biwa, T., Endoh, Y., Shimotsu, M., mixture strength at which the engine is prone to knock Murakami, S., Komoda, T., "The Development of High due to excessively rapid ?ame propagation. Output, Highly Efficient Gas Burning Diesel Engines”. The problem of the premixed gas and air forming too The gaseous fuel for these engines was available at a lean a mixture (at part load) could be alleviated by constant high pressure. The work by Wakenell, et al., throttling the inlet air. However, this is not feasible with 60 carried out at Southwest Research Institute, involved existing turbo-charged engines because of the danger of direct injection of natural gas into a large bore (8.5") compressor surge.

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