Showing papers on "Combustion chamber published in 2005"

Cylinder head gasket

Abstract: The invention relates to a metallic cylinder head gasket for an internal combustion engine having a cylinder block with adjacent combustion chambers and a cylinder head connected to the said block by bolts, having at least one sheet metal layer of resilient metal, which is provided with a plurality of combustion chamber openings corresponding to the combustion chambers of the internal combustion engine, and also fluid and bolt passage openings, where, around each combustion chamber opening, at a distance from the latter, leaving a straight sheet metal section in the opening edge area, a bead is provided, whose spring travel is limited by a stopper extending concentrically with respect to the bead the stopper being profiled in terms of height and/or width in accordance with reductions in compression pressure to be expected in specific areas on account of reduced component stiffness of cylinder block and cylinder head in the clamped state of the cylinder head gasket, where, when profiling the stopper height and/or width, the increase in the compression pressure as a result of thermal expansions to be expected because of the operating temperature of the internal combustion engine is additionally taken into account in such a way that the profiling is designed substantially in accordance with a mid-range between an increase in compression pressure resulting from thermal expansions and a decrease in compression pressure resulting from component stiffnesses.

Gas turbine combustor and operating method thereof

Abstract: A gas turbine combustor has a combustion chamber into which fuel and air are supplied, wherein the fuel and the air are supplied into said combustion chamber as a plurality of coaxial jets.

Method and device for controlling an internal combustion engine

Abstract: An internal combustion engine comprises an intake tract in which a throttle valve is disposed. The engine also comprises a camshaft which acts on gas inlet valves associated with respective cylinders. A phase-adjustment device is used to adjust a phase between the camshaft and a crankshaft. A desired air mass flow in a combustion chamber of the cylinder is determined depending on a charge requirement requested by the driver. The desired air mass flow is adjusted by varying the phase between the camshaft and the crankshaft if the desired air mass flow can be adjusted by varying the phase while substantially maintaining an actual pressure difference upstream and downstream of the throttle valve. Otherwise, the desired air mass flow is adjusted by varying the opening angle of the throttle valve.

PCCI Operation with Early Injection of Conventional Diesel Fuel

Abstract: In order to further reduce exhaust gas emissions, an investigation was carried out concerning premixed charge compression ignition (PCCI) combustion, which is achieved by the early injection of conventional diesel fuel to the combustion chamber. The engine used for the experiments was a single cylinder version of a modern passenger car type common rail engine with a displacement of 550(cm 3 ). An injector with a narrower corn angle was used to prevent interaction of the spray and the cylinder liner. Also, the compression ratio was decreased in order to avoid an excessively advanced ignition situation. Additionally, a large degree of cooled exhaust gas recirculation (EGR) was applied. These measures led to a significantly reduction in NOX emissions. However, a fuel wall-film, which was formed on the surface of the piston bowl wall, caused increases in soot, HC and CO emissions. Also observed was a reduction in indicated mean effective pressure (IMEP), as well as deteriorate in Coefficient of Variation-IMEP (COV IMEP), both of which result from excessively advanced ignition and the formation of lean air-fuel mixture. A measure, consisting of an EGR increase and a small amount of secondary injection, improved IMEP and COV IMEP. It was also effective in reducing soot.

The effect of turbine blade cooling on the cycle efficiency of gas turbine power cycles

Abstract: A thermodynamic cycle analysis computer code for the performance prediction of cooled gas turbines has been used to calculate the efficiency of plants with varying combustor outlet temperature, compressor pressure ratio, and turbomachinery polytropic efficiency. It is shown that the polytropic efficiency exerts a major influence on the optimum operating point of cooled gas turbines: for moderate turbomachinery efficiency the search for enhanced combustor outlet temperature is shown to be logical, but for high turbomachinery efficiency, this is not necessarily so. The sensitivity of the cycle efficiency to variation in the parameters determining the cooling flow rates is also examined. While increases in allowable blade metal temperature and film cooling effectiveness are more beneficial than improvements in other parameters, neither is as important as increase in turbomachinery aerodynamic efficiency.

Methods and apparatus for low emission gas turbine energy generation

Abstract: A low-emission method for producing power using a gas turbine includes premixing a plurality of fuel and air mixtures, injecting the fuel and air mixtures into a combustion chamber using a plurality of fuel nozzles, and adjusting a ratio of fuel and air injected by at least one of the nozzles to control a fuel/air concentration distribution within the combustion chamber

Systems and methods for power generation and hydrogen production with carbon dioxide isolation

Abstract: A power generation system includes a first gas turbine system. The first turbine system includes a first combustion chamber configured to combust a first fuel stream of primarily hydrogen that is substantially free of carbon-based fuels, a first compressor configured to supply a first portion of compressed oxidant to the first combustion chamber and a first turbine configured to receive a first discharge from the first combustion chamber and generate a first exhaust and electrical energy. The power generation system further includes a second gas turbine system. The second turbine system includes a second combustion chamber configured to combust a second fuel stream to generate a second discharge, wherein the first compressor of the first gas turbine system is configured to supply a second portion of compressed oxidant to the second combustion chamber and a second turbine configured to receive the second discharge from the second combustion chamber to generate a second exhaust and electrical energy. A second compressor is configured to receive the second exhaust comprising carbon dioxide and to discharge a recycle stream to the second combustion chamber and a split stream to a separator system adapted to recover carbon dioxide. The power generation system also includes a hydrogen generation system configured to receive a third fuel and steam to generate the first fuel and a third exhaust gas, wherein the third exhaust gas is recycled into the second combustion chamber.

Lean Burn Natural Gas Operation vs. Stoichiometric Operation with EGR and a Three Way Catalyst

Abstract: Exhaust emissions from lean burn natural gas engines may not always be as low as the potential permits, especially engines with open-loop lambda control. These engines can produce much higher emissions than a comparable diesel engine without exhaust gas aftertreatment. Even if the engine has closed-loop lambda control, emissions are often unacceptably high for future emission regulations. A three-way catalyst is, today, the best way to reduce hazardous emissions. The drawback is that the engine has to operate with a stoichiometric mixture and this leads to; higher heat losses, higher pumping work at low to medium loads, higher thermal stress on the engine and higher knock tendency (requiring lower compression ratio, and thus lower brake efficiency). One way to reduce these drawbacks is to dilute the stoichiometric mixture with EGR. This paper compares lean burn operation with operation at stoichiometric conditions diluted with EGR, and using a three-way catalyst. The results show that nitric oxides (NOdx) and hydrocarbon (HC) emissions are several orders of magnitude lower than at lean operation. Higher loads can be achieved, and brake efficiency is higher than lean operation optimized for low NOdx production. A fast burning (high turbulence) combustion chamber is used to allow high amounts of dilution. (Less)

Combustor and combustion method for combustor

Abstract: A combustor and a combustion method for the combustor, which can suppress backfire and ensure stable combustion. The combustor comprises a mixing-chamber forming member for forming therein a mixing chamber in which air for combustion and fuel are mixed with each other, and a combustion chamber for burning a gas mixture mixed in the mixing chamber and producing combustion gases. A channel for supplying the air for combustion to the mixing chamber from the outer peripheral side of the mixing-chamber forming member is provided inside the mixing-chamber forming member. The fuel and the air are premixed in the channel, and a resulting premixed gas mixture is supplied to the mixing chamber.

Reverse-flow gas turbine combustion system

Abstract: A gas turbine combustion system for burning air and fuel into exhaust gases. The gas turbine combustion system may include a combustor, a turbine nozzle integral with the combustor for providing the air to the combustor, and a fuel injector for providing the fuel to the combustor. The turbine nozzle and the fuel injector are positioned within the combustor such that a mixture of the air and the fuel flows in a first direction and the exhaust gases flow in a second direction.

Compression-ignited IC engine and method of operation

Abstract: The present invention is a compression ignition internal combustion engine and method of operation which expands the load limit of quietly operating a premixed charge compression ignition (PCCI) engine by injecting a secondary fuel B, in ratios lean of stoichiometric, either into the intake air stream or directly into the cylinder to form a homogeneous fuel B and air mixture. Near top dead center of the compression stroke, a PCCI-type direct injection of fuel A event is used to initiate combustion of both fuel A and B at the proper time. At low loads the combustion mode is characterized a PCCI-type with high EGR rates. At medium loads the combustion mode is that of homogeneous combustion of fuel B coupled with PCCI combustion of fuel A. At the highest loads the engine will revert to a conventional diesel combustion mode of fuel A to maintain power density.

Cylinder cutoff control apparatus of internal combustion engine

Abstract: A cylinder cutoff control apparatus of an engine initiates a cylinder cutoff mode only when two conditions, namely a low load condition such as a vehicle cruising condition and an intake valve closure timing controlled to a given timing value before a bottom dead center, are both satisfied. A fuel cutoff mode is executed prior to the cylinder cutoff mode. During a transition to the cylinder cutoff mode, the control apparatus holds an intake valve open timing at a given timing value substantially corresponding to a top dead center, simultaneously with reducing an intake valve lift amount of each intake valve, subjected to cylinder cutoff control, to a zero lift. Immediately when the intake valve lift amount is reduced to below a lift threshold value, an exhaust valve lift amount of each exhaust valve, subjected to the cylinder cutoff control, is controlled to a zero lift.

Method for mid load operation of auto-ignition combustion

Abstract: A method is disclosed for expanding the mid load range of a four-stroke gasoline direct-injection controlled auto-ignition combustion engine. The engine includes at least one cylinder containing a piston reciprocably connected with a crank and defining a variable volume combustion chamber including an intake valve controlling communication with an air intake and an exhaust valve controlling communication with an exhaust outlet. A system is employed for variably actuating the intake and exhaust valves. The valve actuating system is employable to operate the intake and exhaust valves with an exhaust re-compression or an exhaust re-breathing valve strategy. A reservoir chamber in communication with the combustion chamber is provided for temporary holding of residual burned gas. Residual burned gas in the combustion chamber and the exhaust outlet enters into the reservoir chamber and then loses thermal energy while in the reservoir chamber before being drawn back into the combustion chamber.

Gaseous fuel burner

Abstract: An ejector, such as a venturi, facilitates the delivery of gaseous fuel to the combustion chamber of a burner. A blower forces air through the ejector, and the air flow produces a suction that draws fuel from a fuel inlet to produce a fuel-air mixture. The amount of fuel drawn from the fuel inlet is a function of the air flow such that a substantially constant fuel-air ratio is obtained over a range of air flow rates and temperatures without the need for a separate high-pressure fuel pump. The fuel-air mixture may be provided to a combustion chamber for combustion. Air from the blower may be pre-heated prior to entering the ejector, for example, using a heat exchanger that recovers some of the heat from the combusted fuel-air mixture. Air flow through the ejector may be conditioned, for example, by a swirler, to produce a tangential air flow that can increase fuel flow by increasing air velocity across the fuel inlet and/or produce a swirl-stabilized flame in the combustion chamber. The combusted fuel-air mixture may be provided to a thermal load, such as an external combustion engine. Blower speed may be controlled manually or automatically to control power output. Fuel flow to the ejector can be controlled manually or automatically to control fuel-air ratio. The burner can be configured to operate with multiple fuel types, for example, using a fuel selector with fixed or variable restrictors.

Assessment of Rich-Burn, Quick-Mix, Lean-Burn Trapped Vortex Combustor for Stationary Gas Turbines

Abstract: This paper describes the evaluation of an alternative combustion approach to achieve low emissions for a wide range of fuel types. This approach combines the potential advantages of a staged rich-burn, quick-mix, lean-burn (RQL) combustor with the revolutionary trapped vortex combustor (TVC) concept. Although RQL combustors have been proposed for low-Btu fuels, this paper considers the application of an RQL combustor for high-Btu natural gas applications. This paper will describe the RQL/TVC concept and experimental results conducted at 10 atm (1013 kPa or 147 psia) and an inlet-air temperature of 644 K (700°F). The results from a simple network reactor model using detailed kinetics are compared to the experimental observations. Neglecting mixing limitations, the simplified model suggests that NOx and CO performance below 10 parts per million could be achieved in an RQL approach. The CO levels predicted by the model are reasonably close to the experimental results over a wide range of operating conditions. The predicted NOx levels are reasonably close for some operating conditions; however, as the rich-stage equivalence ratio increases, the discrepancy between the experiment and the model increases. Mixing limitations are critical in any RQL combustor, and the mixing limitations for this RQL/TVC design are discussed.

A generalized model of acoustic response of turbulent premixed flame and its application to gas-turbine combustion instability analysis

Abstract: An analytical model is developed to study the combustion response of turbulent premixed flames to acoustic oscillations. The analysis is based on a level-set flamelet model, and accommodates spatial variations in chamber geometry and mean-flow properties. All known factors affecting the flame response to local flow disturbances are analyzed. A triple decomposition technique, which expresses each flow variable as the sum of a long-time-averaged, a periodic, and a turbulent component, is used to examine the interactions between acoustic and turbulent motions and their collective influence on the flame dynamics. As specific examples, both a simple and an enveloped flame commonly observed in a swirl-stabilized combustor are studied. The resultant flame response is incorporated into a three-dimensional acoustic analysis to determine the stability characteristics of a model gas-turbine combustor. Results are consistent with experimental observations and numerical simulations in terms of the stability b...

Engine fuel injection control system

Abstract: A system for controlling fuel injection in an engine. The engine includes an intake passage (15), an intake passage injector (18), a cylinder (11) having a combustion chamber (10), and a cylinder injector (17) for injecting a target amount of fuel into the combustion chamber (10). The system includes a controller (21) for controlling the intake passage and cylinder injectors (17, 18) to permit fuel injection, each with an injection ratio, while said engine operates in a condition in which said engine permits fuel injection from said cylinder injector (17). The system also includes a sensor (23) for sensing the amount of fuel injected from the cylinder injector. The system is characterized by a controller (21) for detecting the difference between the target injection amount and the amount of fuel injected (S102), for correcting the injection ratios based on the result of the detection so that the intake passage injector (18) performs fuel injection together with the cylinder injector (17).

Mixing process in high pressure diesel jets by normalized laser induced exciplex fluorescence Part II Wall impinging versus free jet

Abstract: The effect of perpendicular jet wall impingement on the mixing process of high pressure Diesel jets is studied using normalized laser induced exciplex fluorescence (LIEF). A single hole common rail Diesel injector is used which allows high injection pressures up to 200MPa. Visualisations of the jet were performed in a high pressure, high temperature cell that reproduces the thermodynamic conditions which exist in the combustion chamber of a Diesel engine during injection. A LIEF technique is combined to a normalization method in order to obtain fuel vapor concentration fields. The jet-wall interaction configuration is compared to a free jet configuration at identical operating conditions in order to provide detailed information on the influence of wall impingement and its effects on the subsequent mixing process. A significant effect is observed on the mixing rate, which is weaker in the central part of the jet before impact, while it is higher in the jet tip due to the formation of a jet wall vortex. Both effects seem to compensate for one another at an injection pressure of 150MPa, so that the quantity of air entrained in the jet for the jet wall configuration is similar to that of a corresponding free jet. However, at an injection pressure of 200MPa the increased mixing rate at the jet tip becomes predominant due to the intensity of the wall jet vortex, so that the mass of air entrained in the jet is higher in the case of the impinging jet compared to the free jet.

Validation of a Fractal Combustion Model through Flame Imaging

Abstract: The paper is focused on the development of a fractal combustion model, included within a whole-engine one-dimensional model (1 Dime code). An extensive validation is carried out through the comparison with experimental data. The experimental activity was carried out in the combustion chamber of an optically accessible one-cylinder engine, equipped with a commercial head. Experimental data basically consisted on optical measurements which were also correlated to the instantaneous pressure inside the cylinder. Optical measurements were based on 2D digital imaging and UV chemiluminescence of radical species. The rate of chemical energy release and related parameters were evaluated from the in-cylinder pressure data using interpretation models for heat release analysis. Moreover a post-processing of the optical measurements allowed to define the mean flame radius, and propagation speeds as well, as a function of the crank angle. Theoretical and experimental analyses allowed to fully characterize flame structure and propagation speed as well. In order to estimate prediction levels and limitations of the numerical procedure, different engine speeds and spark timings were experimentally analyzed. A good agreement has been found in the whole tested range.

Intercooled Recuperated Gas Turbine Engine Concept

Abstract: *Economical and environmental concerns have world-wide initiated research programs towards a “cleaner engine”, with the objective of a substantial reduction in polluting emissions and fuel consumption. In the context of different programs and international collaborations, MTU has conducted studies to integrate heat exchangers into a novel concept aero engine cycle, a technological innovation that can be extremely beneficial in terms of fuel consumption. NOx emissions and noise levels can also be reduced, thanks to different combustion chamber conditions and to a high bypass ratio configuration. The paper focuses on the thermodynamic cycle and on the necessary technological innovations. An intercooler and a MTU-designed exhaust gas recuperator are applied to a 3-shaft, geared turbofan configuration. The engine is optimized for long range applications, with regard to fuel consumption. Status results for the chosen configurations are presented, together with parametric and optimization studies. Estimations of heat exchanger weight and of engine emissions are finally made.

Benchmark Wall Heat Flux Data for a GO2/GH2 Single Element Combustor

Abstract: Wall heat flux measurements in a 1.5 in. diameter circular cross-section rocket chamber for a uni-element shear coaxial injector element operating on gaseous oxygen (GOz)/gaseous hydrogen (GH,) propellants are presented. The wall heat flux measurements were made using arrays of Gardon type heat flux gauges and coaxial thermocouple instrumentation. Wall heat flux measurements were made for two cases. For the first case, GOZ/GHz oxidizer-rich (O/F=l65) and fuel-rich preburners (O/F=1.09) integrated with the main chamber were utilized to provide vitiated hot fuel and oxidizer to the study shear coaxial injector element. For the second case, the preburners were removed and ambient temperature gaseous oxygen/gaseous hydrogen propellants were supplied to the study injector. Experiments were conducted at four chamber pressures of 750, 600, 450 and 300psia for each case. The overall mixture ratio for the preburner case was 6.6, whereas for the ambient propellant case, the mixture ratio was 6.0. Total propellant flow was nominally 0.27-0.29 Ibm/s for the 750 psia case with flowrates scaled down linearly for lower chamber pressures. The axial heat flux profile results for both the preburner and ambient propellant cases show peak heat flux levels a t axial locations between 2.0 and 3.0 in. from the injector face. The maximum heat flux level was about two times greater for the preburner case. This is attributed to the higher injector fuel-to-oxidizer momentum flux ratio that promotes mixing and higher initial propellant temperature for the preburner case which results in a shorter reaction zone. The axial heat flux profiles were also scaled with respect to the chamber pressure to the power 0.8. The results at the four chamber pressures for both cases collapsed to a single profile indicating that at least to first approximation, the basic fluid dynamic structures in the flow field are pressure independent as long as the chamber/njector/nozzle geometry and injection velocities remain the same.

Concept and combustion characteristics of ultra-micro combustors with premixed flame

Abstract: Under micro-scale combustion influenced by quenching distance, high heat loss, shortened diffusion characteristic time, and flow laminarization, we clarified the most important issues for the combustor of ultra-micro gas turbines (UMGT), such as high space heating rate, low pressure loss, and premixed combustion. The stability behavior of single flames stabilized on top of micro tubes was examined using premixtures of air with hydrogen, methane, and propane to understand the basic combustion behavior of micro premixed flames. When micro tube inner diameters were smaller than 0.4 mm, all of the fuels exhibited critical equivalence ratios in fuel-rich regions, below which no flame formed, and above which the two stability limits of blow-off and extinction appeared at a certain equivalence ratio. The extinction limit for very fuel-rich premixtures was due to heat loss to the surrounding air and the tube. The extinction limit for more diluted fuel-rich premixtures was due to leakage of unburned fuel under the flame base. This clarification and the results of micro flame analysis led to a flat-flame burning method. For hydrogen, a prototype of a flat-flame ultra-micro combustor with a volume of 0.067 cm3 was made and tested. The flame stability region satisfied the optimum operation region of the UMGT with a 16 W output. The temperatures in the combustion chamber were sufficiently high, and the combustion efficiency achieved was more than 99.2%. For methane, the effects on flame stability of an upper wall in the combustion chamber were examined. The results can be explained by the heat loss and flame stretch.

The Effects of High-Pressure Injection on a Compression–Ignition, Direct Injection of Natural Gas Engine

Abstract: This study investigated the effects of injection pressure on the performance and emissions of a pilot-ignited, late-cycle direct-injected natural gas fueled heavy-duty engine. The experiments, conducted on a single-cylinder engine, covered a wide range of engine speeds, loads, and exhaust gas recirculation fractions. The injection pressure was varied at each operating condition while all other parameters were held constant. At high loads, increasing the injection pressure substantially reduced particulate matter and CO emissions, with small increases in NOx and no significant effect on hydrocarbon emissions or fuel consumption. At low loads, injection pressure had no significant impact on either emissions or performance. At high loads, higher injection pressures consistently reduced both the number density and the size of particles in the exhaust stream. Injection pressure had reduced effects at increased engine speeds.

Method for combustion of a fuel

Abstract: In a method for the combustion of a fuel, a fuel or a premixed combustible mixture is introduced into a combustion space as a combustible fluid open jet. The velocity of the open jet is selected in such a way that it is impossible for a stable flame front to form, i.e. is in any event greater than the flame front velocity, and that, on account of a jet pump effect, flue gas is mixed into the combustible fluid jet from the combustion chamber in a jet-induced recirculation internally within the combustion chamber. The admixed flue gas dilutes and heats the combustible fluid. The heating causes the spontaneous ignition temperature to be exceeded, and a low-pollutant volumetric flame is formed in a highly dilute atmosphere.

Low flame temperature limits for mixing-controlled Diesel combustion

Abstract: The low flame temperature limits for mixing-controlled Diesel combustion were investigated in a constant-volume combustion chamber at well-defined ambient conditions Flame temperatures were controlled by varying ambient oxygen concentration or by using fuel-lean mixing-controlled combustion Pressure rise measurements show that combustion efficiency remains high for flame temperatures as low as 1500–1600 K for conditions where the ambient gas temperature was greater than 1000 K This low flame temperature limit is less than those of propagating flame processes in engines but close to that of HCCI combustion Chemiluminescence imaging shows that a cool flame exists prior to the quasi-steady lift-off length, suggesting that ignition processes are continuously occurring within the Diesel fuel jet as air and fuel mix upstream of the high-temperature reaction zone at the lift-off length