CA1122422A - Vehicle propulsion system - Google Patents
Vehicle propulsion systemInfo
- Publication number
- CA1122422A CA1122422A CA256,537A CA256537A CA1122422A CA 1122422 A CA1122422 A CA 1122422A CA 256537 A CA256537 A CA 256537A CA 1122422 A CA1122422 A CA 1122422A
- Authority
- CA
- Canada
- Prior art keywords
- steam
- engine
- accordance
- internal combustion
- exhaust gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000002485 combustion reaction Methods 0.000 claims abstract description 72
- 239000007789 gas Substances 0.000 claims abstract description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 25
- 239000000203 mixture Substances 0.000 claims description 21
- 239000000446 fuel Substances 0.000 claims description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 11
- 238000001816 cooling Methods 0.000 claims description 9
- 238000006073 displacement reaction Methods 0.000 claims description 9
- 238000002156 mixing Methods 0.000 claims description 7
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 239000012530 fluid Substances 0.000 claims description 5
- 230000007246 mechanism Effects 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 3
- 230000001133 acceleration Effects 0.000 claims description 2
- 230000008878 coupling Effects 0.000 claims description 2
- 238000010168 coupling process Methods 0.000 claims description 2
- 238000005859 coupling reaction Methods 0.000 claims description 2
- 238000004146 energy storage Methods 0.000 claims description 2
- 239000000047 product Substances 0.000 claims 5
- 230000001276 controlling effect Effects 0.000 claims 4
- 150000001875 compounds Chemical group 0.000 claims 1
- 238000003303 reheating Methods 0.000 claims 1
- 239000013589 supplement Substances 0.000 claims 1
- 238000011144 upstream manufacturing Methods 0.000 claims 1
- 239000003344 environmental pollutant Substances 0.000 abstract description 6
- 231100000719 pollutant Toxicity 0.000 abstract description 6
- 239000000543 intermediate Substances 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 208000036366 Sensation of pressure Diseases 0.000 description 2
- 230000009194 climbing Effects 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 239000012809 cooling fluid Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 241001527806 Iti Species 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001141 propulsive effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000002000 scavenging effect Effects 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G3/00—Combustion-product positive-displacement engine plants
- F02G3/02—Combustion-product positive-displacement engine plants with reciprocating-piston engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/12—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engines being mechanically coupled
- F01K23/14—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engines being mechanically coupled including at least one combustion engine
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
- F02G1/00—Hot gas positive-displacement engine plants
- F02G1/02—Hot gas positive-displacement engine plants of open-cycle type
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
ABSTRACT
A hybrid vehicle propulsion system is disclosed which utilizes an internal combustion engine, an afterburner, and a steam engine in combination for improved efficiency and reduced emission of pollutants. The afterburner is pro-vided to reduce the level of pollutants emitted and to in-crease the temperature of the exhaust gases from the internal combustion engine. The heat from the exhaust gases, together with the heat removed from the internal combustion cylinders, is then utilized in the steam engine to provide additional propulsion.
A hybrid vehicle propulsion system is disclosed which utilizes an internal combustion engine, an afterburner, and a steam engine in combination for improved efficiency and reduced emission of pollutants. The afterburner is pro-vided to reduce the level of pollutants emitted and to in-crease the temperature of the exhaust gases from the internal combustion engine. The heat from the exhaust gases, together with the heat removed from the internal combustion cylinders, is then utilized in the steam engine to provide additional propulsion.
Description
The instant invention provides a hybrid internal combustion and steam engine system yielding good fuel economy over the load and rpm ranges encountered in vehicle propulsion systems, while minimizing pollutant emissions. These usually mutually-exclusive goals of high efficiency an~
low pollution cannot be obtained by conventional non-hybrid systems.
The hybrid propulsion system according to the instant invention provides, in general, for the conversion oE the heat energy lost in the internal combustion cylinders to mechanical energy by use oE a Rankine cycle engine such as a steam engine. The steam engine operates both on the heat content of the cooling fluid in the conventional cooling system used to remove a portion of the heat of combustion from the internal combustion cylinder chambers and also on the heat content of the internal combustion engine exhaust gases.
The invention provides a vehicle propulsion system comprising an internal combustion engine combined with a steam engine, means for directing exhaust gas from the internal combustion engine to a steam generator coupled to provide steam to a steam engine, a transmission for mechanically coupling the internal combustion engine and the steam engine to propel the vehicle, means for providing the combustion chamber of the internal combustion engine with a fuel-air mixture in which the fuel-air ratio is substantially greater than the stoichiometric fuel-air ratio in order to produce a combusted exhaust gas from the internal combustion engine which is low in oxides of nitrogen content and rich in combustibles content, means for introducing air downstream of the engine for mixing with said exhaust gas to support further combustion thereof, a combustion device coupled to receive the exhaust gas to complete the combustion of said exhaust gas, and means for controlling the relative contributions of the internal combustion engine and the steam engine to the propulsion system by adjusting the respective inputs of the engines in accordance with load demand and the pressure of generated steam.
From another aspect, the invention provides the method of reducing the output of polluting emissions while improving the economy of a vehicle ,~,,i1 propulsion system having an internal combustion engine in combination with a steam engine by using the heat oF combusted exhaust gas from the internal combustion engine to generate steam and applying the steam to the steam engine to develop mechanical work therefrom, comprising the steps of provid ing the combustion chamber of an internal combustion engine with a com-bustible mixture having a fuel-alr ratio substantially greater than stoichiometric in order to produce a combusted exhaust gas from the internal combustion engine which is low in oxides of nitrogen content and rich in combustibles content; introducing air downstream of the engine for mixing with the combustibles-rich exhaust gas to support further combustion thereof;
completing the combustion of the exhaust-air mixture; directing the further-combusted gas to a steam generator; and controlling the relative contri-butions of the two engines to the propulsion system by adjusting the respec-tive inputs of the engines in accordance with load demand and the pressure of generated steam.
The internal combustion (I.C.) engine of the system of this inven-tion is operated at an air-fuel mixture providing minimized unburnable pollutants (N0 ), and an afterburner is provided to recover the chemical energy in the exhaust gases while eliminating substantially all the com-bustible pollutants. The afterburner serves as a second heat source to increase the temperature of the internal combustion engine exhaust gases.
These gases are then directed to a steam generator where they are used to boil and to superheat the already-heated cooling fluid in a high-pressure boiler for subsequent use in a high-pressure expander section of a steam engine to develop mechanical power.
The fluid discharge from the high-pressure expander section is combined with the vapor formed in the cooling system and reheated by heat exchange with the exhaust gases. These combined fluids are then used to operate a lower-pressure expander section of a steam engine to develop additional propulsion. The discharge from the lower-pressure expander section is returned to a condenser similar to a conventional radiator for condensation before return to the cooling jackets surrounding the engine ~;~' cylinders, and to the steam generator unit (boiler) in the exhaust gas _~ .
low pollution cannot be obtained by conventional non-hybrid systems.
The hybrid propulsion system according to the instant invention provides, in general, for the conversion oE the heat energy lost in the internal combustion cylinders to mechanical energy by use oE a Rankine cycle engine such as a steam engine. The steam engine operates both on the heat content of the cooling fluid in the conventional cooling system used to remove a portion of the heat of combustion from the internal combustion cylinder chambers and also on the heat content of the internal combustion engine exhaust gases.
The invention provides a vehicle propulsion system comprising an internal combustion engine combined with a steam engine, means for directing exhaust gas from the internal combustion engine to a steam generator coupled to provide steam to a steam engine, a transmission for mechanically coupling the internal combustion engine and the steam engine to propel the vehicle, means for providing the combustion chamber of the internal combustion engine with a fuel-air mixture in which the fuel-air ratio is substantially greater than the stoichiometric fuel-air ratio in order to produce a combusted exhaust gas from the internal combustion engine which is low in oxides of nitrogen content and rich in combustibles content, means for introducing air downstream of the engine for mixing with said exhaust gas to support further combustion thereof, a combustion device coupled to receive the exhaust gas to complete the combustion of said exhaust gas, and means for controlling the relative contributions of the internal combustion engine and the steam engine to the propulsion system by adjusting the respective inputs of the engines in accordance with load demand and the pressure of generated steam.
From another aspect, the invention provides the method of reducing the output of polluting emissions while improving the economy of a vehicle ,~,,i1 propulsion system having an internal combustion engine in combination with a steam engine by using the heat oF combusted exhaust gas from the internal combustion engine to generate steam and applying the steam to the steam engine to develop mechanical work therefrom, comprising the steps of provid ing the combustion chamber of an internal combustion engine with a com-bustible mixture having a fuel-alr ratio substantially greater than stoichiometric in order to produce a combusted exhaust gas from the internal combustion engine which is low in oxides of nitrogen content and rich in combustibles content; introducing air downstream of the engine for mixing with the combustibles-rich exhaust gas to support further combustion thereof;
completing the combustion of the exhaust-air mixture; directing the further-combusted gas to a steam generator; and controlling the relative contri-butions of the two engines to the propulsion system by adjusting the respec-tive inputs of the engines in accordance with load demand and the pressure of generated steam.
The internal combustion (I.C.) engine of the system of this inven-tion is operated at an air-fuel mixture providing minimized unburnable pollutants (N0 ), and an afterburner is provided to recover the chemical energy in the exhaust gases while eliminating substantially all the com-bustible pollutants. The afterburner serves as a second heat source to increase the temperature of the internal combustion engine exhaust gases.
These gases are then directed to a steam generator where they are used to boil and to superheat the already-heated cooling fluid in a high-pressure boiler for subsequent use in a high-pressure expander section of a steam engine to develop mechanical power.
The fluid discharge from the high-pressure expander section is combined with the vapor formed in the cooling system and reheated by heat exchange with the exhaust gases. These combined fluids are then used to operate a lower-pressure expander section of a steam engine to develop additional propulsion. The discharge from the lower-pressure expander section is returned to a condenser similar to a conventional radiator for condensation before return to the cooling jackets surrounding the engine ~;~' cylinders, and to the steam generator unit (boiler) in the exhaust gas _~ .
2~
stream.
Figure 1 is a combination block and schematic diagram illustrating the particulars of the present invention;
Figure 2 is a diagram showing the throttle control mechanism for the arrangement of Figure l;
Figure 3 i9 a graph showing N0 production as a function of air-fuel ratio in an automoti.ve engine; and Figure 4 is a graph showing the performance map of a typical passenger car engine in operation.
A preferred embodiment of the invention is shown schematically in block diagram form in Figure 1. Air and fuel are supplied to conven-tional carburetor 10 having a throttle 11, and a mixture is supplied to the I.C. engine 12. The mixture provided by the carburetor 10 is purposely made richer than stoichiometric, in a range oE fuel-air ratios between .075 ancl .120, preferably about .090. The exhaust gas from the I.C. engine, which under moderate to heavy loads will be at a temperature in the range of 1000 F and for a fuel-air ratio of .090 input to the engine will contain about 3.5% hydrogen and 8% carbon monoxide, is mixed with air from air source 14 (which may typically be a blower driven as an accessory) in either exhaust pipe 16 or afterburner 17 and the combustible mixture burned in afterburner 17. This combustion releases sufficient heat to raise the exhaust gas -3a-Z~:
temperature to approximately 2300F.
The exhaust gas from the internal combusti.on engine is sufficiently rich in combustibles that when mixed with sufficient air a combustion reaction can be initiated by a spark, and maintained by suitable combustion chamber design.
Back mixing of hot burnt exhaust into the fresh mix-ture by well known methods such as flameholders, opposing jets, or other methods of providing recirculation is an efEective and suitable method of burning this exhaust. The air may be introduced into the exhaust gas any time after the expansive stroke in the I.C. engine cylinder has been essentially completedj e.g., as extra scavenging air in a two-stroke engine, from ports opened by exhaust valve opening in a four-stroke engine, in the piping between the cylinder and the afterburner, or in the aEterburner itself. A conventional spark plug fired by the I.C. engine ignition sy~stem is placed in a low velocity region of the flow for initial ignition of the exhaust gas-air mixture. It is useful to provide a region of unrecirculated flow after the main combustion has taken place to finish off the combustion. Normally the transition from the afterburner to the associated steam generator unit 18 will provide this.
A combustion chamber volume of between 100 and 200 cubic inches is a suitable size for the afterburner. The burnt exhaust gas is conducted to steam generator unit 18, which pre-ferably consists of approximately 150 feet of steel tubing approximately 1/~ inches inside diameter and 3/8 inches out-side diameter within a suitable casing.
A convenient arrangement of the steel tubing is to wind two adjacent coiIs of approximately ten layers, the coils having an inside diameter of about 3 inches and an l~Z~ 2 outside diameter of 10 inches, with a length of 5 inches for each coil. F.xhaust gas is lntroduced into the space at the center of the first coil, flows radially outward over the steel tubing, emerges from the first coil and is then ducted and directed radially inward through the second coil. It emerges in the center of the second coil substantially cooled by virtue of the transfer of-its heat energy to the fluid flowing within the steel tubing and is ready for discharge to the atmosphere. Water from a boiler feed pump 20 is introduced into the tubing at the center of the second coil, flows spirally outward through the gecond coil and then spirally in-ward through the first coil until it is discharged as steam to a throttle valve 22.
The exhaust gas is cooled to about 500F in the pro-cess of transferring lts heat to the water in steam generator unit 18. The water and the exhaust gas are preferably in sub-stantially counter-current flow heat transfer relationship within the steam generator unit 18. Suitable operating con-ditions for the steam generator unit 18 are to introduce the feed water at 1500 psi and 180F from the boiler feed pump 20, and for the ~enerator 18 to produce 900F superheated steam. The steam generator unit 18 may be conceptually dlvi-ded into four sections, which are the superheater 18a, the boiler 18b, the feedwater heater or economizer 18c, and the optional reheater 18d. Normally the second coil is the economizer 18c, and the first coil serves the function of boiler 18b and superheater 18a. The optional reheater 18d is composed of additional tubing inserted into the ducting between the first coil and the second coil, or may be integrated into the casing.
The feedwater first enters the economizer 18c where it is heated to the boiling temperature, which for a pres~
sure of 1500 psi is 650F. The heated water passes into the boiler section l~b where the transferred heat converts the water into steam~ The steam leaves the boiler and proceeds to the superlleater 18a where additional heat is added to superheat the steam. Practical designs of steam generator ~mits often utilize the "once through" concept where the wa~er is p~ped through a tube or tubes countercurrent to the heat source fluid flow. In such a generator the boundary between feedwater heater and boiler, and between boiler and superheater may vary considerably with operating conditions without material consequence insofar as ~he opera~ion of the steam generator unit is concerned. The steam generator 1 essentially consists of some relatively small high pressure steel tubing through which the water flows, climbing in temperature until it boils, then turning into steam at constant temperature as it advances further, and eventually after being fully vaporized, climbing further in temperature until delivered from the steam generator unit I8. Steam throttle 22 controls the application of the high pressure steam B to a steam ~ 24 having high pressure section 24a and low pressure section 24b.
The internal combustion engine 12 is provided with a water (or comparable liquid) cooling jacket 30 which is arranged to operate substantially above atmospheric pres-sure. Water is provided to it by a low pressure output con-nection on thé boiler feed pump 20, driven as an accessor-y, or by a separate boiler feed pu~p (not shown). Heat lost to the cylinder walls and head of the I.C. engine converts some of æ
the jacket water to stean, which is separated from the water in a steam/water separator 32. This steam is merged in a junction element 34 with low pressure steam that is the exl~aust from the intermediate pressure cylinder which is the second stage of the hlgh pressure section 24a of the steam engine 24, directed through the reheater section l~d oE the steam generator unit 18, and expanded in the low pressure cylinders section 24b of the steam engine 24. A throttle valve 50 is provided for controlling the steam supply from the I.C. engine jacket 30 and separator 32 to the low pressure cylinders.
A check valve 52 is placed in this line to prevent steam from the inter-mediate cylinder exhaust back-flowing into the steam/water separator unit 32 and the I.C. engine jacket 30 during warmup of the system. The exhaust from the low pressure cylinders is directed to a condenser 36 and associated hot we]l 38 where the steam is condensed to water and the heat of condensation rejected to the atmosphere with the assistance of a cooling fan 39.
Superheated high pressure steam is delivered at pressures such as 1500 psi, and temperatures such as 900 F to the steam engine 24, where a portion of the heat energy of the steam is converted into work. The steam expansion is preferably conducted in several stages. In one embodiment the steam engine has four cylinders, one high pressure, one intermediate pressure, and two low pressure. Design center steam pressure values for the high pressure cylinder are 1500 psia inlet and 400 psia exhaust; values for the intermediate cylinder are 400 psia inlet and 100 psia exhaust, and for the two low pressure cylinders, lO0 psia inlet and 20 psia exhaust.
~'22~
e~ e The mechanical output of the steam e*~ ~E 24 is delivered through output shaft 40 via over-running clutch 42 to the I.C. engine shaft 44. The combined power of the two engines is delivered to transmission 46 which transmits the power to the drive wheels of the vehicle.
For an intermediate-sized American car of about 3500 lbs. weight, the displacement of the I.C. engine 12 should be chosen in the range of 80 to L00 cubic inches, and the er~gJr~e steam ~æ~eæ 24 should have a displacement of about 126 cubic lnches. The steam ~ displacement is preferably distributed among the cylinders with 6 cubic inches in the high pressure cylinder, 20 cubic inches in the intermediate pressure cylinder, and 50 cubic inches in each of the low pressure cylinders. The four cylinders may be in-line, or have any other suitable mechanical arrangement. Each cylinder is provided with conventional steam inlet exhaust valves, not shown, preferably càm-operated poppet valves similar to those used in automotive practice. Power control is pre-ferably exercised by steam inlet cutoff control 23 on the high pressure cylinder, and throttling via throttle 50 of the steam supply from the steam water separator 32 to the low pressure cylinders which should operate with steam inlet valve cutoff of about 30% of stroke. For turning over the steam engine from a full stop, means may be provided to extend cutoff to 70% of stroke, and small bleeds from the high pressure steam supply arranged so that intermediate pressure and low pressure steam is available at the start. The high pressure steam throttle 22 is also provided to extend the range of power control when the inlet valve cutoff has been reduced to a practical minimum, and to cut off the steam supply to the ~ 2~
engine completely when desired. The control of the duration of admission of steam supply to the high pressure cylinder may be accomplished by methods well known to those skilled in the art, such as operating the inlet valve with a three dimensional cam that is geared to the crankshaft, and is trans-lated to give the variously desired angles of admlssion.
- - Alternatively a series poppet valve arrangement may be used, one controlling admission, and the other cutoff. Steam is admitted to the cylinder only when both valves are open, and the phase between the two valves is obtained by suitable differential rotations of their respective camshafts, an arrangement known in the prior art.
The normal steam admission duration to the high pressure cylinder under full torque load con~itions wlll be;
in thè range of 20 to 30% of strokej and for various cruise conditions be in the range of 5% to 20% of s-troke. Under surge conditions the admission will be increased to a maximum of about 70% - 80% of stro~e. The steam consumption and the B e~g~'ne consequent power of the steam ~p2~eæ 24 is controlled ~y the coordinated operation of the high pressure throttle 22, the low pressure throttle 50, and the high pressure cylinder inlet valve-steam admission cutoff control (not shown). As more power is demanded of the steam engine, the two throttles are opened further, and the steam admission time lengthened.
The cranks of the high and the intermediate pressure cylinders of section 24a may be disposed at an angle of 180 to each other, in which case the high pressure cylinder exhaust valve can also serve as the intermedlate cylinder inlet valve, i.e., a transfer valve. The exhaust steam from the lntermedlate pressure cyllnder is merged ln junction element 34 with the _g_ Z~22 steam from the steamjwater separator 15 and conducted through the reheater section 18c of the steam generator unit 18. Under various low power conditions the exhaust from the intermediate cylinder can be at a lower pressure than the steam supply from the engine jacket, so a check valve 33 is placed between the exhaust of the intermediate pressure cylinder and steam line junction element 34.
The condenser 36 is about the same size, and may go in the same place, as the standard automobile radiator.
The heat transfer requirements are somewhat greater, but not substantially so, than those of the standard automobile radiator. The condenser 36 is preferably constructed of externally finned vertical steel tubes, ~or the strength ~o resist internal pressure, and the geometry to avoid damage when the water freezes. The vertical condenser tubes are connected between headers at the top and bottom, and the-sides of the bottom plenum are mad~ sufficiently flexible to ac-commodate expansion of the accumulated water during feeezing.
This bottom plenum is made sufficiently large so that it can contain all the water that could accu~ulate in the condenser during shutdown without the water level rising into the vertical tubes. The bottom plenum of the condenser may serve as the hot well 38, or a separate flexlble-walled container may be provided. Water from the hot well 38 is pumped by the boiler feed pump(s) such as 20 to the I.C. engine cooling jacket 30 and to the steam generator unit 18. A vacuum line 54 is con-nected from the condenser 36 and hot well 38 via check valve 56 to the I.C. en~ine intake manifold to collect and dispose of the non-condensibles that may accumulate in the steam system due to decomposition of steam cylinder lubricating oil, and ' ~ ~ 2'~ ~2 ~
in-leakage of air through imperfect seals. The flow is suit-ably restricted to prevent excessive quan~ities of steam from being admitted to the I.C. engine. Thus the check valve 56 may be provided with a restricted orifice to permit limited flow in a one-way direction only without disrupting the mix-ture at the I.C. engine inlet under any operating conditions.
Coordinated control of the power of the I.C. engine E~ etl~qin~
12 and the steam e~Fa~6~ 24 may be achieved by a control unit ~ such as is illustrated in Fig. 2. In the unit ~3 of Fig.2 a link rod 61 is connected to the standard foot control pedal that is operated by the driver of the car. Slotted arms 62 and 64 connected together by shafts 65a, 65b are caused to rotate about the axis of shaft 65b mounted in base 63 by the motion o'f link rod 61. Control rods 67 and 69 connected to the various throttles and cutoff control at the points desig-nated "C" in Fig. 1 have pins 66 and 68 riding in the slots - in the control arms 62, 64. The linkage consisting of links 70 and 72 joined by link 71 is actuated by rod 73 to control the relative demand made upon the I.C. engine and the steam en~ / ~e e~a~e~ to provide the power call'ed for by the driver's ac-tuation of the power control pedal and consequently the link rod 61. Rod 73 is moved upward with increase of steam pres-sure i.n line 81 applled to piston 80 in cylinde:r 82'against spring 84. This upward motîon moves the pin on steam power control rod 69 higher in the slot in arm 64) and the pin'on I.C. engine throttle control rod 67 lower in the slot in arm 62, with the effect that as the steam pressure in-creases, the operation of the'linkage arranges that more power will be called for from the steam engine, and less from the I.C. engine. Thus, when steam pressure is larger than the 1 ~ ~f~ ~2Z
desired predetermined value, steam will be drawn from the boiler and cooling jacket at a greater rate, and the I.C.
engine will operate at a lower Fuel and air throughput to make less exhaust gas, and less heat for the steam generator 18 and englne jacket 30. Accordingly, the two eEfects cooperate to bring the steam pressure to the desired predetermined value.
Similarly if the steam pressure is less than the desired predetermined value, the mechanism will operate in the reverse 8 manner to increase the I.C, engine throughput and exhaust eng I r~e.
gas flow, and reduce the steam e*~ e~ steam consumption.
Fig. 3 shows the general trend of oxidesof nitrogen prod~lction in standard American au~omobile engines for two dif-ferent cities, Cincinnati and Los Angeles, as a function of the fuel--air ratio in the rnixture fed to the engine. It is apparent from this data that changing the fuel-air ratio of the gasoline-air mixture fed to the internal combustion engine from the standard value of .0714 to the preferred value of .090 for this invention wlll effect an overall reduction of NOX
emission from .020 lbs~/vehicle mile to about .0025 lbs./
vehicle mile, before crediting the system with the propulsive effort delivered by the steam engine; including this credit demonstrates an overall reduction in oxides of nitrogen emission by a factor of about sixteen.
Fig. 4 is a graph of a performance map of the conventional I.C. engine installed in an average Americarl car.
The broken line 90 on the map represents level road load. It is readily apparent that the road load condition is far from the region of best efficiency. The best efficiency is at a brake mean effective pressure (bmep) of ab'out 100 psi, and a piston speed of 1000 ft/min. (approximately the point 92).
~ 2 ~
With a conventional engine in a standard automobile, fifty milesan hour cruise in hlgh gear corresponds to a piston speed of about 1500 ftlminute, and one can see from Fig. 3 ~hat the road load bmep is about 22 psi, and the brake specific fuel consumption (bsfc) is 0.8 lbs/hp-hr. ~hen the conventional engine is replaced with the new engine system of this inven-tion, the I.C. engine of the new engine system under the comparable condition is loaded to a bmep of ~4 psi, and lts bsfc would be 0.6 lb/hp-hr if it were conventionally carbureted. For the preferred carburetion 1.4 times as much fuel is fed to the I.C. engine for a total fuel consumption of 0.82 lb. per I.C. engine horsepower hour. Since the steam engine part of the system provides an amount of power about equal to that provided by the I.C. engine of the system, the overall bsfc of the combined system is half the above value--. about .42 lb/hp-hr. This i5 about half the fuel consumption of the conventional I.C. engine.
Overall the new engine is twice as fuel-efficient in automotive service as the conventional powerplant.
Furthermore combustible pollutants have been reduced to ex-tremely low values in the afterburner, far below any levels presently set by any air pollution control agency. In addition ~he N0x emissions have been reduced by a factor be-tween lO and 16 below the levels emit-ted by-presently produced engines. This has been done without compromlse of fuel economy but instead a dramatic improvement therein has been achieved.
In this preferred application of the engine to~the propulsion task, the peak steady state power available from the `30 system is less than that available from the conventional ~ 2 ~'2Z
internal combustion engine. However, by taking advantage of the fact that energy storage in the hot water and hot metal of the steam generator unit 18 provides a reservoir from which energy may be drawn for surge power capability, this~engine will provide acceleration capability in city traffic, freeway on-ramp accPleration, and passing maneuvers on the open highway. What will be given up in performance in the previously discussed sizing of the engine system to the load is the ability to tow a heavy load up a 10% grade at 60 mph, or to operate the vehicle on the level at speeds above 100 mph. If this performance were necessary in special cases, such as for law enforcement vehicles, the displacement of the I.C. engine and steam engine in the system need only be chosen somewhat larger, at some cost in fuel economy.
The engine system as shown in Fig. 1 of the drawing and described in conjunction therewith is essentially a sche-matic representation of the preferred embodiment of my invention. Numerous variations may be Pmployed as a matter of design choice. For example, engine accessories such as the pumps, fan, blower and the like may be shaft-driven from -the Sz'~ en.~/ne B ~c~e~ or the I.C. engine J or -they may be driven by motors from the electrical system. Other arrangements than that shown in Fig. 2 may be employed to coordinat.e the operation of ~he steam and gas engine throttles and other controls.
stream.
Figure 1 is a combination block and schematic diagram illustrating the particulars of the present invention;
Figure 2 is a diagram showing the throttle control mechanism for the arrangement of Figure l;
Figure 3 i9 a graph showing N0 production as a function of air-fuel ratio in an automoti.ve engine; and Figure 4 is a graph showing the performance map of a typical passenger car engine in operation.
A preferred embodiment of the invention is shown schematically in block diagram form in Figure 1. Air and fuel are supplied to conven-tional carburetor 10 having a throttle 11, and a mixture is supplied to the I.C. engine 12. The mixture provided by the carburetor 10 is purposely made richer than stoichiometric, in a range oE fuel-air ratios between .075 ancl .120, preferably about .090. The exhaust gas from the I.C. engine, which under moderate to heavy loads will be at a temperature in the range of 1000 F and for a fuel-air ratio of .090 input to the engine will contain about 3.5% hydrogen and 8% carbon monoxide, is mixed with air from air source 14 (which may typically be a blower driven as an accessory) in either exhaust pipe 16 or afterburner 17 and the combustible mixture burned in afterburner 17. This combustion releases sufficient heat to raise the exhaust gas -3a-Z~:
temperature to approximately 2300F.
The exhaust gas from the internal combusti.on engine is sufficiently rich in combustibles that when mixed with sufficient air a combustion reaction can be initiated by a spark, and maintained by suitable combustion chamber design.
Back mixing of hot burnt exhaust into the fresh mix-ture by well known methods such as flameholders, opposing jets, or other methods of providing recirculation is an efEective and suitable method of burning this exhaust. The air may be introduced into the exhaust gas any time after the expansive stroke in the I.C. engine cylinder has been essentially completedj e.g., as extra scavenging air in a two-stroke engine, from ports opened by exhaust valve opening in a four-stroke engine, in the piping between the cylinder and the afterburner, or in the aEterburner itself. A conventional spark plug fired by the I.C. engine ignition sy~stem is placed in a low velocity region of the flow for initial ignition of the exhaust gas-air mixture. It is useful to provide a region of unrecirculated flow after the main combustion has taken place to finish off the combustion. Normally the transition from the afterburner to the associated steam generator unit 18 will provide this.
A combustion chamber volume of between 100 and 200 cubic inches is a suitable size for the afterburner. The burnt exhaust gas is conducted to steam generator unit 18, which pre-ferably consists of approximately 150 feet of steel tubing approximately 1/~ inches inside diameter and 3/8 inches out-side diameter within a suitable casing.
A convenient arrangement of the steel tubing is to wind two adjacent coiIs of approximately ten layers, the coils having an inside diameter of about 3 inches and an l~Z~ 2 outside diameter of 10 inches, with a length of 5 inches for each coil. F.xhaust gas is lntroduced into the space at the center of the first coil, flows radially outward over the steel tubing, emerges from the first coil and is then ducted and directed radially inward through the second coil. It emerges in the center of the second coil substantially cooled by virtue of the transfer of-its heat energy to the fluid flowing within the steel tubing and is ready for discharge to the atmosphere. Water from a boiler feed pump 20 is introduced into the tubing at the center of the second coil, flows spirally outward through the gecond coil and then spirally in-ward through the first coil until it is discharged as steam to a throttle valve 22.
The exhaust gas is cooled to about 500F in the pro-cess of transferring lts heat to the water in steam generator unit 18. The water and the exhaust gas are preferably in sub-stantially counter-current flow heat transfer relationship within the steam generator unit 18. Suitable operating con-ditions for the steam generator unit 18 are to introduce the feed water at 1500 psi and 180F from the boiler feed pump 20, and for the ~enerator 18 to produce 900F superheated steam. The steam generator unit 18 may be conceptually dlvi-ded into four sections, which are the superheater 18a, the boiler 18b, the feedwater heater or economizer 18c, and the optional reheater 18d. Normally the second coil is the economizer 18c, and the first coil serves the function of boiler 18b and superheater 18a. The optional reheater 18d is composed of additional tubing inserted into the ducting between the first coil and the second coil, or may be integrated into the casing.
The feedwater first enters the economizer 18c where it is heated to the boiling temperature, which for a pres~
sure of 1500 psi is 650F. The heated water passes into the boiler section l~b where the transferred heat converts the water into steam~ The steam leaves the boiler and proceeds to the superlleater 18a where additional heat is added to superheat the steam. Practical designs of steam generator ~mits often utilize the "once through" concept where the wa~er is p~ped through a tube or tubes countercurrent to the heat source fluid flow. In such a generator the boundary between feedwater heater and boiler, and between boiler and superheater may vary considerably with operating conditions without material consequence insofar as ~he opera~ion of the steam generator unit is concerned. The steam generator 1 essentially consists of some relatively small high pressure steel tubing through which the water flows, climbing in temperature until it boils, then turning into steam at constant temperature as it advances further, and eventually after being fully vaporized, climbing further in temperature until delivered from the steam generator unit I8. Steam throttle 22 controls the application of the high pressure steam B to a steam ~ 24 having high pressure section 24a and low pressure section 24b.
The internal combustion engine 12 is provided with a water (or comparable liquid) cooling jacket 30 which is arranged to operate substantially above atmospheric pres-sure. Water is provided to it by a low pressure output con-nection on thé boiler feed pump 20, driven as an accessor-y, or by a separate boiler feed pu~p (not shown). Heat lost to the cylinder walls and head of the I.C. engine converts some of æ
the jacket water to stean, which is separated from the water in a steam/water separator 32. This steam is merged in a junction element 34 with low pressure steam that is the exl~aust from the intermediate pressure cylinder which is the second stage of the hlgh pressure section 24a of the steam engine 24, directed through the reheater section l~d oE the steam generator unit 18, and expanded in the low pressure cylinders section 24b of the steam engine 24. A throttle valve 50 is provided for controlling the steam supply from the I.C. engine jacket 30 and separator 32 to the low pressure cylinders.
A check valve 52 is placed in this line to prevent steam from the inter-mediate cylinder exhaust back-flowing into the steam/water separator unit 32 and the I.C. engine jacket 30 during warmup of the system. The exhaust from the low pressure cylinders is directed to a condenser 36 and associated hot we]l 38 where the steam is condensed to water and the heat of condensation rejected to the atmosphere with the assistance of a cooling fan 39.
Superheated high pressure steam is delivered at pressures such as 1500 psi, and temperatures such as 900 F to the steam engine 24, where a portion of the heat energy of the steam is converted into work. The steam expansion is preferably conducted in several stages. In one embodiment the steam engine has four cylinders, one high pressure, one intermediate pressure, and two low pressure. Design center steam pressure values for the high pressure cylinder are 1500 psia inlet and 400 psia exhaust; values for the intermediate cylinder are 400 psia inlet and 100 psia exhaust, and for the two low pressure cylinders, lO0 psia inlet and 20 psia exhaust.
~'22~
e~ e The mechanical output of the steam e*~ ~E 24 is delivered through output shaft 40 via over-running clutch 42 to the I.C. engine shaft 44. The combined power of the two engines is delivered to transmission 46 which transmits the power to the drive wheels of the vehicle.
For an intermediate-sized American car of about 3500 lbs. weight, the displacement of the I.C. engine 12 should be chosen in the range of 80 to L00 cubic inches, and the er~gJr~e steam ~æ~eæ 24 should have a displacement of about 126 cubic lnches. The steam ~ displacement is preferably distributed among the cylinders with 6 cubic inches in the high pressure cylinder, 20 cubic inches in the intermediate pressure cylinder, and 50 cubic inches in each of the low pressure cylinders. The four cylinders may be in-line, or have any other suitable mechanical arrangement. Each cylinder is provided with conventional steam inlet exhaust valves, not shown, preferably càm-operated poppet valves similar to those used in automotive practice. Power control is pre-ferably exercised by steam inlet cutoff control 23 on the high pressure cylinder, and throttling via throttle 50 of the steam supply from the steam water separator 32 to the low pressure cylinders which should operate with steam inlet valve cutoff of about 30% of stroke. For turning over the steam engine from a full stop, means may be provided to extend cutoff to 70% of stroke, and small bleeds from the high pressure steam supply arranged so that intermediate pressure and low pressure steam is available at the start. The high pressure steam throttle 22 is also provided to extend the range of power control when the inlet valve cutoff has been reduced to a practical minimum, and to cut off the steam supply to the ~ 2~
engine completely when desired. The control of the duration of admission of steam supply to the high pressure cylinder may be accomplished by methods well known to those skilled in the art, such as operating the inlet valve with a three dimensional cam that is geared to the crankshaft, and is trans-lated to give the variously desired angles of admlssion.
- - Alternatively a series poppet valve arrangement may be used, one controlling admission, and the other cutoff. Steam is admitted to the cylinder only when both valves are open, and the phase between the two valves is obtained by suitable differential rotations of their respective camshafts, an arrangement known in the prior art.
The normal steam admission duration to the high pressure cylinder under full torque load con~itions wlll be;
in thè range of 20 to 30% of strokej and for various cruise conditions be in the range of 5% to 20% of s-troke. Under surge conditions the admission will be increased to a maximum of about 70% - 80% of stro~e. The steam consumption and the B e~g~'ne consequent power of the steam ~p2~eæ 24 is controlled ~y the coordinated operation of the high pressure throttle 22, the low pressure throttle 50, and the high pressure cylinder inlet valve-steam admission cutoff control (not shown). As more power is demanded of the steam engine, the two throttles are opened further, and the steam admission time lengthened.
The cranks of the high and the intermediate pressure cylinders of section 24a may be disposed at an angle of 180 to each other, in which case the high pressure cylinder exhaust valve can also serve as the intermedlate cylinder inlet valve, i.e., a transfer valve. The exhaust steam from the lntermedlate pressure cyllnder is merged ln junction element 34 with the _g_ Z~22 steam from the steamjwater separator 15 and conducted through the reheater section 18c of the steam generator unit 18. Under various low power conditions the exhaust from the intermediate cylinder can be at a lower pressure than the steam supply from the engine jacket, so a check valve 33 is placed between the exhaust of the intermediate pressure cylinder and steam line junction element 34.
The condenser 36 is about the same size, and may go in the same place, as the standard automobile radiator.
The heat transfer requirements are somewhat greater, but not substantially so, than those of the standard automobile radiator. The condenser 36 is preferably constructed of externally finned vertical steel tubes, ~or the strength ~o resist internal pressure, and the geometry to avoid damage when the water freezes. The vertical condenser tubes are connected between headers at the top and bottom, and the-sides of the bottom plenum are mad~ sufficiently flexible to ac-commodate expansion of the accumulated water during feeezing.
This bottom plenum is made sufficiently large so that it can contain all the water that could accu~ulate in the condenser during shutdown without the water level rising into the vertical tubes. The bottom plenum of the condenser may serve as the hot well 38, or a separate flexlble-walled container may be provided. Water from the hot well 38 is pumped by the boiler feed pump(s) such as 20 to the I.C. engine cooling jacket 30 and to the steam generator unit 18. A vacuum line 54 is con-nected from the condenser 36 and hot well 38 via check valve 56 to the I.C. en~ine intake manifold to collect and dispose of the non-condensibles that may accumulate in the steam system due to decomposition of steam cylinder lubricating oil, and ' ~ ~ 2'~ ~2 ~
in-leakage of air through imperfect seals. The flow is suit-ably restricted to prevent excessive quan~ities of steam from being admitted to the I.C. engine. Thus the check valve 56 may be provided with a restricted orifice to permit limited flow in a one-way direction only without disrupting the mix-ture at the I.C. engine inlet under any operating conditions.
Coordinated control of the power of the I.C. engine E~ etl~qin~
12 and the steam e~Fa~6~ 24 may be achieved by a control unit ~ such as is illustrated in Fig. 2. In the unit ~3 of Fig.2 a link rod 61 is connected to the standard foot control pedal that is operated by the driver of the car. Slotted arms 62 and 64 connected together by shafts 65a, 65b are caused to rotate about the axis of shaft 65b mounted in base 63 by the motion o'f link rod 61. Control rods 67 and 69 connected to the various throttles and cutoff control at the points desig-nated "C" in Fig. 1 have pins 66 and 68 riding in the slots - in the control arms 62, 64. The linkage consisting of links 70 and 72 joined by link 71 is actuated by rod 73 to control the relative demand made upon the I.C. engine and the steam en~ / ~e e~a~e~ to provide the power call'ed for by the driver's ac-tuation of the power control pedal and consequently the link rod 61. Rod 73 is moved upward with increase of steam pres-sure i.n line 81 applled to piston 80 in cylinde:r 82'against spring 84. This upward motîon moves the pin on steam power control rod 69 higher in the slot in arm 64) and the pin'on I.C. engine throttle control rod 67 lower in the slot in arm 62, with the effect that as the steam pressure in-creases, the operation of the'linkage arranges that more power will be called for from the steam engine, and less from the I.C. engine. Thus, when steam pressure is larger than the 1 ~ ~f~ ~2Z
desired predetermined value, steam will be drawn from the boiler and cooling jacket at a greater rate, and the I.C.
engine will operate at a lower Fuel and air throughput to make less exhaust gas, and less heat for the steam generator 18 and englne jacket 30. Accordingly, the two eEfects cooperate to bring the steam pressure to the desired predetermined value.
Similarly if the steam pressure is less than the desired predetermined value, the mechanism will operate in the reverse 8 manner to increase the I.C, engine throughput and exhaust eng I r~e.
gas flow, and reduce the steam e*~ e~ steam consumption.
Fig. 3 shows the general trend of oxidesof nitrogen prod~lction in standard American au~omobile engines for two dif-ferent cities, Cincinnati and Los Angeles, as a function of the fuel--air ratio in the rnixture fed to the engine. It is apparent from this data that changing the fuel-air ratio of the gasoline-air mixture fed to the internal combustion engine from the standard value of .0714 to the preferred value of .090 for this invention wlll effect an overall reduction of NOX
emission from .020 lbs~/vehicle mile to about .0025 lbs./
vehicle mile, before crediting the system with the propulsive effort delivered by the steam engine; including this credit demonstrates an overall reduction in oxides of nitrogen emission by a factor of about sixteen.
Fig. 4 is a graph of a performance map of the conventional I.C. engine installed in an average Americarl car.
The broken line 90 on the map represents level road load. It is readily apparent that the road load condition is far from the region of best efficiency. The best efficiency is at a brake mean effective pressure (bmep) of ab'out 100 psi, and a piston speed of 1000 ft/min. (approximately the point 92).
~ 2 ~
With a conventional engine in a standard automobile, fifty milesan hour cruise in hlgh gear corresponds to a piston speed of about 1500 ftlminute, and one can see from Fig. 3 ~hat the road load bmep is about 22 psi, and the brake specific fuel consumption (bsfc) is 0.8 lbs/hp-hr. ~hen the conventional engine is replaced with the new engine system of this inven-tion, the I.C. engine of the new engine system under the comparable condition is loaded to a bmep of ~4 psi, and lts bsfc would be 0.6 lb/hp-hr if it were conventionally carbureted. For the preferred carburetion 1.4 times as much fuel is fed to the I.C. engine for a total fuel consumption of 0.82 lb. per I.C. engine horsepower hour. Since the steam engine part of the system provides an amount of power about equal to that provided by the I.C. engine of the system, the overall bsfc of the combined system is half the above value--. about .42 lb/hp-hr. This i5 about half the fuel consumption of the conventional I.C. engine.
Overall the new engine is twice as fuel-efficient in automotive service as the conventional powerplant.
Furthermore combustible pollutants have been reduced to ex-tremely low values in the afterburner, far below any levels presently set by any air pollution control agency. In addition ~he N0x emissions have been reduced by a factor be-tween lO and 16 below the levels emit-ted by-presently produced engines. This has been done without compromlse of fuel economy but instead a dramatic improvement therein has been achieved.
In this preferred application of the engine to~the propulsion task, the peak steady state power available from the `30 system is less than that available from the conventional ~ 2 ~'2Z
internal combustion engine. However, by taking advantage of the fact that energy storage in the hot water and hot metal of the steam generator unit 18 provides a reservoir from which energy may be drawn for surge power capability, this~engine will provide acceleration capability in city traffic, freeway on-ramp accPleration, and passing maneuvers on the open highway. What will be given up in performance in the previously discussed sizing of the engine system to the load is the ability to tow a heavy load up a 10% grade at 60 mph, or to operate the vehicle on the level at speeds above 100 mph. If this performance were necessary in special cases, such as for law enforcement vehicles, the displacement of the I.C. engine and steam engine in the system need only be chosen somewhat larger, at some cost in fuel economy.
The engine system as shown in Fig. 1 of the drawing and described in conjunction therewith is essentially a sche-matic representation of the preferred embodiment of my invention. Numerous variations may be Pmployed as a matter of design choice. For example, engine accessories such as the pumps, fan, blower and the like may be shaft-driven from -the Sz'~ en.~/ne B ~c~e~ or the I.C. engine J or -they may be driven by motors from the electrical system. Other arrangements than that shown in Fig. 2 may be employed to coordinat.e the operation of ~he steam and gas engine throttles and other controls.
Claims (29)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The method of reducing the output of polluting emissions while improving the economy of a vehicle propulsion system having an internal com-bustion engine in combination with a steam engine by using the heat of com-busted exhaust gas from the internal combustion engine to generate steam and applying the steam to the steam engine to develop mechanical work therefrom, comprising the steps of providing the combustion chamber of an internal combustion engine with a combustible mixture having a fuel-air ratio sub-stantially greater than stoichiometric in order to produce a combusted exhaust gas from the internal combustion engine which is low in oxides of nitrogen content and rich in combustibles content; introducing air downstream of the engine for mixing with the combustibles-rich exhaust gas to support further combustion thereof; completing the combustion of the exhaust-air mixture; directing the further-combusted gas to a steam generator; and con-trolling the relative contributions of the two engines to the propulsion system by adjusting the respective inputs of the engines in accordance with load demand and the pressure of generated steam.
2. The method of claim 1 wherein said combustible mixture has a fuel-air ratio in the range of .075 to .125.
3. The method of claim 2 further including mixing the fuel and air in the ratio of approximately .090.
4. The method of any of claims 1-3 further including applying the combusted exhaust gas to a superheater, a boiler and an economizer in succession; the superheater, boiler and economizer being coupled in series relationship with respect to the flow of an evaporative fluid therethrough.
5. The method of claim 1, 2 or 3 further including the steps of:
storing heat energy in the steam generator during periods of steady-state operation at average and low power demands; and removing the energy stored in said storing step, during short periods of peak power demand, to provide additional mechanical power from the steam expander.
storing heat energy in the steam generator during periods of steady-state operation at average and low power demands; and removing the energy stored in said storing step, during short periods of peak power demand, to provide additional mechanical power from the steam expander.
6. A vehicle propulsion system comprising an internal combustion engine combined with a steam engine, means for directing exhaust gas from the internal combustion engine to a steam generator coupled to provide steam to a steam engine, a transmission for mechanically coupling the internal combustion engine and the steam engine to propel the vehicle, means for pro-viding the combustion chamber of the internal combustion engine with a fuel-air mixture in which the fuel-air ratio is substantially greater than the stoichiometric fuel-air ratio in order to produce a combusted exhaust gas from the internal combustion engine which is low in oxides of nitrogen con-tent and rich in combustibles content, means for introducing air downstream of the engine for mixing with said exhaust gas to support further combustion thereof, a combustion device coupled to receive the exhaust gas to complete the combustion of said exhaust gas, and means for controlling the relative contributions of the internal combustion engine and the steam engine to the propulsion system by adjusting the respective inputs of the engines in accordance with load demand and the pressure of generated steam.
7. Apparatus in accordance with claim 6 wherein the combustion device includes an air admitting member for adding air to the exhaust gas to permit the completion of combustion thereof.
8. Apparatus in accordance with claim 6 wherein the combustion device comprises an afterburner.
9. Apparatus in accordance with claim 6 further including a super-heater in series with a boiler and positioned to receive the exhaust gas from the combustion device upstream of the boiler.
10. Apparatus in accordance with claim 6 wherein the internal com-bustion engine includes a water cooling jacket and further including means for deriving steam from said jacket and applying it to the steam engine.
11. Apparatus in accordance with claim 10 further including means for separating steam from water in the cooling jacket and means for mixing this steam with steam from the steam generator for application to the steam engine.
12. Apparatus in accordance with any of claims 6-8 wherein the means for providing the fuel-air mixture includes means for establishing a fuel-air ratio in the range of .075 to .125.
13. Apparatus in accordance with claims 6, 7 or 8 wherein the means for providing the fuel air mixture includes means for establishing a fuel-air ratio of approximately .090.
14. Apparatus in accordance with claims 6, 7 or 8 wherein the steam engine comprises a compound unit having a high pressure section and a low pressure section and further includes a reheater connected to receive ex-hausted steam from the high pressure section and apply it to the low pressure section after reheating.
15. Apparatus in accordance with claim 14 wherein the reheater is located to absorb heat from the exhaust gas stream downstream of the steam generator boiler.
16. Apparatus in accordance with claim 9 further including an econo-mizer positioned in heat transfer relationship with the exhaust gas downstream of the boiler for preheating water with heat drawn from the exhaust gas prior to the introduction of the water to the boiler.
17. Apparatus in accordance with claim 6 further including a power controller for controlling the fuel-air mixture input into the internal combustion engine and the steam input to the steam engine.
18. Apparatus in accordance with claim 17 further including a co-ordinator for coordinating the operation of the power controller in accordance with the availability of steam from the steam generator.
19. Apparatus in accordance with claim 18 wherein the coordinator includes a linkage mechanism for driving the power controller in unison in response to operator control input while adjusting the fuel air mixture relative to the steam input to the steam engine in accordance with the availability of steam from the steam generator.
20. Apparatus in accordance with claim 15 further including a steam generator pressure responder for adjusting the relationship of fuel-air mix-ture to steam engine input in response to operator control input.
21. Apparatus in accordance with claim 6 further including a condenser for condensing the steam engine exhaust steam.
22. Apparatus in accordance with claim 21 further including means for removing non-condensible products from the condenser and directing them to the input of the internal combustion engine for combustion therein.
23. Apparatus in accordance with claim 22 wherein the removing means comprises a check valve having a restricted orifice for passing the non-condensible products from the condenser to the internal combustion engine input without disrupting the operation of the internal combustion engine.
24. Apparatus in accordance with claim 14 wherein the high pressure section of the steam engine comprises a first high pressure cylinder and a second intermediate pressure cylinder, and the low pressure section of the steam engine comprises a pair of low pressure cylinders of approximately equal displacement.
25. Apparatus in accordance with claim 24 wherein the high pressure cylinder has a displacement of 6 cubic inches, the intermediate pressure cylinder has a displacement of 20 cubic inches and the low pressure cylinders each have a displacement of 50 cubic inches.
26. A vehicle propulsion system in accordance with claim 6 wherein the internal combustion engine has a substantially smaller displacement than a conventional internal combustion engine of equivalent power and is normally operated at higher cylinder pressures and a higher efficiency than such con-ventional engine when subjected to the same load and speed conditions; further including a steam generator coupled in heat exchange relationship with the combusted exhaust gas from the combustion device, the steam engine being coupled to receive steam from the steam generator and to generate mechanical power therefrom, the steam engine being operable to provide sufficient steady-state power to supplement the internal combustion engine adequately for most vehicle operating conditions, and the steam generator having sufficient heat capacity to act as an energy storage reservoir which may be drawn upon for short periods of vehicle acceleration; and further comprising first and second power control means for controlling the fuel-air mixture input to the internal combustion engine and the steam input to the steam engine, respectively, and means for coordinating the operation of the power control means in accordance with the availability of steam from the steam generator, the coordinating means having a linkage mechanism for driving the first and second power control means in unison in response to operator control input while adjusting the operation of one power control means relative to the other in accordance with the availability of steam from the steam generator.
27. A vehicle propulsion system in accordance with claim 26 wherein the coordinating means further includes means responsive to steam generator pressure for adjusting the relative control of the first and second power control means in response to operator input.
28. A vehicle propulsion system in accordance with claim 26 wherein the steam engine further includes a condenser coupled to receive exhaust steam from the steam engine, and means for removing non-condensible products from the condenser and directing them to the input of the internal combustion engine for combustion therein.
29. A vehicle propulsion system in accordance with claim 28 wherein the means for removing non-condensible products comprises a check valve having a restricted orifice for passing the non-condensible products from the condenser to the internal combustion engine input without disrupting the operation of the internal combustion engine.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US59888875A | 1975-07-24 | 1975-07-24 | |
| US598,888 | 1975-07-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1122422A true CA1122422A (en) | 1982-04-27 |
Family
ID=24397334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA256,537A Expired CA1122422A (en) | 1975-07-24 | 1976-07-07 | Vehicle propulsion system |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5925850B2 (en) |
| CA (1) | CA1122422A (en) |
| DE (1) | DE2558919A1 (en) |
| FR (1) | FR2326576A1 (en) |
| GB (1) | GB1554766A (en) |
| IT (1) | IT1070356B (en) |
| SE (1) | SE438710B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2933369A1 (en) * | 1979-08-17 | 1981-03-26 | Rudolf Kurt Hermann Ing.(grad.) 5860 Iserlohn Wuttke | IC engine for vehicle - has steam turbine coupled to it to recover heat in engine cooling water and exhaust gases |
| DE19610382C2 (en) * | 1996-03-16 | 2000-06-29 | Reinhard Leithner | Combi engine |
| DE10054022A1 (en) | 2000-11-01 | 2002-05-08 | Bayerische Motoren Werke Ag | Method for operating a heat engine |
| DE20117271U1 (en) * | 2001-10-20 | 2002-01-03 | Enginion Ag | internal combustion engine |
| DE10211317A1 (en) * | 2002-03-14 | 2004-04-22 | Thorwald Buck | Ecological system for utilization of waste heat from combustion engines in steam power process has for steam power process a pump, heat exchangers, steam power machine and condenser |
| DE102007002611A1 (en) | 2007-01-12 | 2008-07-24 | Voith Patent Gmbh | Hybrid drive unit with an internal combustion engine and a steam engine |
| WO2010099941A1 (en) * | 2009-03-04 | 2010-09-10 | Voith Patent Gmbh | Steam cycle process device |
| DE102010015039A1 (en) * | 2010-04-15 | 2013-01-31 | Ziemann Energy Gmbh | Combustion plant for wet manure and the like |
| DE102010031498A1 (en) | 2010-07-19 | 2012-01-19 | Robert Bosch Gmbh | Electromagnetic clutch for connecting a steam engine to an internal combustion engine |
| FR2985767B1 (en) * | 2012-01-18 | 2019-03-15 | IFP Energies Nouvelles | DEVICE FOR CONTROLLING A WORKING FLUID IN A CLOSED CIRCUIT OPERATING ACCORDING TO A RANKINE CYCLE AND METHOD USING SUCH A DEVICE |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR965772A (en) * | 1950-09-21 | |||
| DE310184C (en) * | ||||
| US1230617A (en) * | 1913-12-05 | 1917-06-19 | William Joseph Still | Internal-combustion engine. |
| US1339177A (en) * | 1916-03-14 | 1920-05-04 | Leonard H Dyer | Power plant |
| US2688843A (en) * | 1945-11-13 | 1954-09-14 | Solar Aircraft Co | Apparatus for augmenting mass and velocity of exhaust streams |
| DE2116824A1 (en) * | 1971-04-06 | 1972-10-19 | Hagiu, Faust, Dipl Ing , 8000 Mun chen | Antnebsgruppe |
| US3877229A (en) * | 1972-11-15 | 1975-04-15 | Cornell Res Foundation Inc | Combustion means for a low-pollution engine |
-
1975
- 1975-12-29 DE DE19752558919 patent/DE2558919A1/en active Granted
-
1976
- 1976-05-21 JP JP51058968A patent/JPS5925850B2/en not_active Expired
- 1976-07-07 CA CA256,537A patent/CA1122422A/en not_active Expired
- 1976-07-14 GB GB29374/76A patent/GB1554766A/en not_active Expired
- 1976-07-20 SE SE7608268A patent/SE438710B/en not_active IP Right Cessation
- 1976-07-22 IT IT83409/76A patent/IT1070356B/en active
- 1976-07-23 FR FR7622668A patent/FR2326576A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5925850B2 (en) | 1984-06-21 |
| DE2558919A1 (en) | 1977-02-10 |
| GB1554766A (en) | 1979-10-31 |
| SE7608268L (en) | 1977-01-25 |
| DE2558919C2 (en) | 1990-02-08 |
| FR2326576A1 (en) | 1977-04-29 |
| JPS5215949A (en) | 1977-02-05 |
| IT1070356B (en) | 1985-03-29 |
| FR2326576B1 (en) | 1980-07-11 |
| SE438710B (en) | 1985-04-29 |
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| MKEX | Expiry |