Showing papers on "Four-stroke engine published in 2007"

Engine mounting configuration for a turbofan gas turbine engine

Abstract: An engine mounting configuration reacts engine thrust at an aft mount. The engine mounting configuration reduces backbone bending of the engine, intermediate case distortion and frees-up space within the core nacelle.

Cylinder charge temperature control for an internal combustion engine

Abstract: A method is disclosed for operating an engine with a first cylinder providing a net flow of gases from the intake to the exhaust while combusting; and a second cylinder providing a net flow of gases from the exhaust to the intake. Both the first and second cylinders may carry out combustion during such operation.

Dynamic Load and Stress Analysis of a Crankshaft

Abstract: In this study a dynamic simulation was conducted on a crankshaft from a single cylinder four stroke engine. Finite element analysis was performed to obtain the variation of stress magnitude at critical locations. The pressure-volume diagram was used to calculate the load boundary condition in dynamic simulation model, and other simulation inputs were taken from the engine specification chart. The dynamic analysis was done analytically and was verified by simulation in ADAMS which resulted in the load spectrum applied to crank pin bearing. This load was applied to the FE model in ABAQUS, and boundary conditions were applied according to the engine mounting conditions. The analysis was done for different engine speeds and as a result critical engine speed and critical region on the crankshaft were obtained. Stress variation over the engine cycle and the effect of torsional load in the analysis were investigated. Results from FE analysis were verified by strain gages attached to several locations on the crankshaft. Results achieved from aforementioned analysis can be used in fatigue life calculation and optimization of this component.

Method for stopping and starting an internal combustion engine having a variable event valvetrain

Abstract: A method for controlling stopping and starting of an engine having a variable event valvetrain is described. According to the method engine valves may be used to reduce engine evaporative emissions as well as engine starting emissions. Since the engine configuration shown has electrically actuated intake and exhaust valves it is possible to reconfigure the engine operating sequence during a start. For example, the pistons for cylinders two and three are in the same position at the same time. This allows either cylinder to be set to an intake stroke during a subsequent engine restart when the piston is traveling away from the cylinder head while the companion cylinder is set to the expansion or power stroke. Thus, the cylinder having the first intake stroke could be configured to provide a first combustion event during an engine restart. On the other hand, the cylinder set to the power stroke could have been set to the intake stroke such that it is the first cylinder to provide a combustion stroke during a restart.

Engine pre-lubrication system

Abstract: A system (10) for pre-lubricating an engine (12) is disclosed. The system (10) has the engine (12), a first pump (22) driven by the engine (12) to lubricate the engine (12), and a second pump (42) configured to lubricate the engine (12). The system (10) also has at least one component driven by the engine (12) and fluidly connected downstream of the second pump (42) and upstream of the engine (12). System (10) further has a sensor (54) located at the engine (12) to generate a signal indicative of an engine lubrication status. Starting of the engine (12) is inhibited based on the engine lubrication status.

Two-stage Fuel Direct Injection in a Diesel Fuelled HCCI Engine

Abstract: Two-stage fuel direct injection (DI) has the potential to expand the operating region and control the autoignition timing in a Diesel fuelled homogeneous charge compression ignition (HCCI) engine. In this work, to investigate the dual-injection HCCI combustion, a stochastic reactor model, based on a probability density function (PDF) approach, is utilized. A new wall-impingement sub-model is incorporated into the stochastic spray model for direct injection. The model is then validated against measurements for combustion parameters and emissions carried out on a four stroke HCCI engine. The initial results of our numerical simulation reveal that the two-stage injection is capable of triggering the charge ignition on account of locally rich fuel parcels under certain operating conditions, and consequently extending the HCCI operating range. Furthermore, both simulated and experimental results on the effect of second injection timing on combustion indicate that there exists an optimal second injection timing to gain maximum engine output work for a given fuel split ratio.

Control of supercharged engine

Abstract: There is provided a method of controlling an engine system. The engine system comprises an internal combustion engine, a supercharging system having at least one supercharger to boost intake air to the internal combustion engine, a turbine, and a motor. The turbine receives an exhaust gas flow from an exhaust system of the internal combustion engine and is capable of at least partly driving the supercharging system. The motor is capable of at least partly driving the supercharging system. The method comprises operating the exhaust system in a first exhaust state and operating the motor in a first motor state when a speed of the internal combustion engine is below a first engine speed, operating the exhaust system in the first exhaust state and operating the motor in a second motor state where power to drive the motor is reduced from that in the first motor state when the speed of the internal combustion engine is between the first engine speed and a second engine speed which greater the said first engine speed, and operating the exhaust system in a second exhaust state where energy transmitted from the internal combustion engine to the turbine is reduced from that in the first exhaust state and operating the motor in the second motor state when the speed of the internal combustion engine is above the second engine speed. Accordingly, the maximum torque can be increased while maintaining the system efficiency over the entire engine speed range.

Method and apparatus for engine piston installation by use of industrial robots

Abstract: A method and apparatus for engine piston installation in which robots are used for the entire engine piston installation process. A first robot equipped with a stuffing gripper and force control picks up a piston with a connection rod, detects the piston ring presence, squeeze the rings, find the engine cylinder bore, and stuffs the piston into the cylinder bore. A second robot can be used to load and unload the engine block, hold the block and position it to the location, and indexes the crankshaft into the proper orientation for each cylinder bore. A set of tools either fixed on a stationary station or on a third robot is used to guide the piston connecting rod, transport and place on the connecting rod cap, and fasten the cap onto the connecting rod. The piston connecting rod guiding process may be omitted in piston stuffing for some types of engines.

Ignition recognition method for a spark-ignited internal combustion engine in which ignition of the cylinder is recognized when the rotational speed of the crankshaft is slowed compared to a reference value

Abstract: Rotational speed of crankshaft during a compression cycle of the cylinder is measured during a time interval in the sequence of operations of the internal combustion engine. A knock signal during a working cycle of the cylinder is detected during a second time interval in the sequence of operations of the internal combustion engine. Ignition of the cylinder is recognized when the rotational speed of the crankshaft is slowed compared to a reference value. A knocking combustion has been detected due to the knock signal. An independent claim is included for an internal combustion engine.

Multi-mode 2-stroke/4-stroke internal combustion engine

Abstract: In a multi-mode, 2-stroke/4-stroke internal combustion engine operation, by switching the engine stroke from 4-stroke operation to 2-stroke operation so that the combustion frequency is doubled, doubling of the engine power is achieved even at the same work output per cycle. In order to meet the demand of extremely high power, the engine operates in 4-stroke boosted SI operation transitioned from 2-stroke HCCI operation at pre-set level of power and crank speed requirements. By combining the multi-stroke (2- stroke HCCI and 4-stroke HCCI) and multi-mode operation (2-stroke HCCI and 4-stroke boosted SI operation), full load range and overall high efficiency with minimal NOx emission are achieved.

Method for operating an internal combustion engine and internal combustion engine for such a method

Abstract: The invention relates to a method for operating a direct-injection, self-striking internal combustion engine, and a correspondingly configured internal combustion engine. Into a piston head (5) of the piston (2), a piston recess (6) is formed, which passes into an essentially ring-shaped staging chamber (7) in the transition region of the piston head (5). Injection jets (9, 9') of an injection unit (8) are fed to the staging chamber (7) and there diverted in such a way that a first partial quantity (11) of fuel is diverted into the piston recess (6) in an axial direction (14) and a radial direction (15), that a second partial quantity (12) of fuel in the axial direction (14) and the radial direction (15) is diverted into the combustion chamber (4) via the piston head (5), and that a third partial quantity (13) of fuel is diverted into a circumferential direction (16), wherein each of the three partial quantities (13, 13') of adjacent injection jets (9, 9') meet together in the circumferential direction (16) and are subsequently diverted inwards in the radial direction (15).

Split-cycle aircraft engine

Abstract: A split -cycle aircraft engine includes a crankshaft rotatable about a crankshaft axis. A power piston is slidably received within a power cylinder and is operatively connected to the crankshaft such that the power piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A compression piston is slidably received within a compression cylinder and is operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single, rotation of the crankshaft. A gas crossover passage operatively interconnects the compression cylinder and the power cylinder. An air reservoir is operatively connected to the gas crossover passage by a reservoir passage. The air reservoir is selectively operable to receive and deliver compressed air. The engine is mounted to an aircraft and the air reservoir is disposed within the aircraft.A split -cycle aircraft engine includes a crankshaft rotatable about a crankshaft axis. A power piston is slidably received within a power cylinder and is operatively connected to the crankshaft such that the power piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A compression piston is slidably received within a compression cylinder and is operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single, rotation of the crankshaft. A gas crossover passage operatively interconnects the compression cylinder and the power cylinder. An air reservoir is operatively connected to the gas crossover passage by a reservoir passage. The air reservoir is selectively operable to receive and deliver compressed air. The engine is mounted to an aircraft and the air reservoir is disposed within the aircraft.A split -cycle aircraft engine includes a crankshaft rotatable about a crankshaft axis. A power piston is slidably received within a power cylinder and is operatively connected to the crankshaft such that the power piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A compression piston is slidably received within a compression cylinder and is operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single, rotation of the crankshaft. A gas crossover passage operatively interconnects the compression cylinder and the power cylinder. An air reservoir is operatively connected to the gas crossover passage by a reservoir passage. The air reservoir is selectively operable to receive and deliver compressed air. The engine is mounted to an aircraft and the air reservoir is disposed within the aircraft.

Starter arrangement for an internal combustion engine

Abstract: A starter arrangement for an internal combustion engine the arrangement including a starter motor having a pinion gear coupled to an output shaft, the pinion gear being arranged in constant engagement with a corresponding crank gear of a crank wheel located between an engine block and a flywheel of the engine. The crank wheel is operatively coupled to a crankshaft of the engine via a one-way clutch unit loosely fitted to an end of the crankshaft, the crankshaft including a circumferential slot carrying a clip ring. The one-way clutch unit including a tube shaped hub loosely fitted to an end of the crankshaft, the axial movement of the one-way hub is fixed via a clip-ring in co-operation with a first axially delimiting member and a second axially delimiting member at least partially enclosed by the hub.

Internal combustion engine with alternator

Abstract: An internal combustion engine has a combustion chamber having a spark plug arranged thereat. A crankcase supports a crankshaft. An intake for introducing fuel and combustion air into the combustion chamber is provided. An exhaust for exhausting combustion gases from the combustion chamber is provided. A piston is connected to the crankshaft and drives the crankshaft in rotation. A wheel member is connected to the crankshaft and rotates with the crankshaft. An alternator driven by the crankshaft supplies electric power to a consumer. The alternator is arranged within a radial boundary of the wheel member and external to the crankcase. The alternator has a stator and a rotor, wherein the crankshaft penetrates the stator and wherein the rotor is fixedly connected to the wheel member.

Method and apparatus for determining piston position in an engine

Abstract: The invention comprises a method to determine a position of a piston in a cylinder of an engine during ongoing operation, comprising adapting pressure sensing devices to monitor in-cylinder pressure, and, operating the engine. In-cylinder pressure is monitored along with a corresponding engine crank position. The engine is operated in a motoring mode and in a cylinder firing mode, and a plurality of instantaneous in-cylinder pressure states are determined during compression and expansion strokes. Pressure ratios are determined based upon the instantaneous in-cylinder pressure states, which are used to determine an engine crank angle and compression ratio error and, adjust the monitored engine crank position based upon the crank angle error and readjust engine operation according to these sensed errors.

Variable compression ratio dual crankshaft engine

Abstract: A synchronized, dual crankshaft engine ( 10 ) uses a phase-shifting device ( 42 ) to alter the angular position of one crankshaft ( 12 ) relative to the other crankshaft ( 14 ) for dynamically varying the engine's developed compression ratio. Each crankshaft ( 12, 14 ) drives a respective connecting rod ( 16, 18 ) which, in turn, reciprocates a piston ( 24, 26 ) in a cylinder ( 28, 30 ). The center lines (C, D) of each cylinder ( 28, 30 ) are skewed relative to each other so that the pistons ( 24, 26 ) converge toward a common combustion chamber formed under a common cylinder head ( 34 ). Movable exhaust valves ( 36 ) are located above the piston ( 24 ) whose phase shifted orientation is retarded or lagging dead center conditions, whereas movable intake valves ( 38 ) are located above the piston ( 26 ) that is leading or advanced in its phase displacement relative to dead center conditions.

Nagata cycle rotary engine

Abstract: An internal combustion rotary engine using vanes to create separate combustion chambers within the engine and capable of performing all four strokes of the Otto cycle (intake, compression, combustion and exhaust) in each separate combustion chamber. Each Otto cycle is completed in a 180-degree rotation with all four strokes of the Otto cycle being completed in 720 degrees. An intake and exhaust valve system tightly controls the flow of the air/fuel mixture into each separate combustion chamber.

Engine including speed-change actuator

Abstract: To lower the center of gravity of the entire engine including a speed-change actuator for realization of the lowered center of gravity of a vehicle in which the engine is mounted and to suppress the effect on an arrangement space for components above the engine. In an engine including a transmission which is provided in a power transmission pathway to a drive wheel, a counter shaft which is an output shaft of the transmission, an engine case in which a crankshaft and the transmission are accommodated, and a speed-change actuator which is attached to the engine case, the speed-change actuator is arranged below relative to the counter shaft.

Method and apparatus for controlling transitions in an engine having multi-step valve lift

Abstract: There is provided a method for controlling engine valves of an internal combustion engine adapted to selectively operate at one of a first open position and a second open position, including controlling engine operation during a transition from a first to a second combustion mode. The method comprises determining a desired engine airflow based upon an operator torque request. A cylinder intake volume is determined for the desired engine airflow when operating at the first open position. A control scheme is determined to control the engine valves to attain the cylinder intake volume for the desired engine airflow when operating at the second open position. The control scheme is executed and the engine valve is transitioned to the second open position when the cylinder intake volume to operate at the second open position is within a range of authority of the engine valves.

Numerical and Experimental Analysis of the Intake Flow in a High Performance Four-Stroke Motorcycle Engine: Influence of the Two-Equation Turbulence Models

Abstract: An experimental and numerical analysis of the intake system of a production high performance four-stroke motorcycle engine was carried out. The aim of the work was to characterize the fluid dynamic behavior of the engine during the intake phase and to evaluate the capability of the most commonly used two-equation turbulence models to reproduce the in-cylinder flow field for a very complex engine head. Pressure and mass flow rates were measured on a steady-flow rig. Furthermore, velocity measurements were obtained within the combustion chamber using laser Doppler anemometry (LDA). The experimental data were compared to the numerical results using four two-equation turbulence models (standard k-e, realizable k-e, Wilcox k-w, and SST k-ω models). All the investigated turbulence models well predicted the global performances of the intake system and the mean flow structure inside the cylinder. Some differences between measurements and computations were found close to the cylinder head while an improving agreement was evident moving away from the engine head. Furthermore, the Wilcox k-w model permitted the flow field inside the combustion chamber of the engine to be reproduced and the overall angular momentum of the flux with respect to the cylinder axis to be quantified more properly.

Performance, Efficiency, and Emissions Characterization of Reciprocating Internal Combustion Engines Fueled with Hydrogen/Natural Gas Blends

Abstract: Hydrogen is an attractive fuel source not only because it is abundant and renewable but also because it produces almost zero regulated emissions. Internal combustion engines fueled by compressed natural gas (CNG) are operated throughout a variety of industries in a number of mobile and stationary applications. While CNG engines offer many advantages over conventional gasoline and diesel combustion engines, CNG engine performance can be substantially improved in the lean operating region. Lean operation has a number of benefits, the most notable of which is reduced emissions. However, the extremely low flame propagation velocities of CNG greatly restrict the lean operating limits of CNG engines. Hydrogen, however, has a high flame speed and a wide operating limit that extends into the lean region. The addition of hydrogen to a CNG engine makes it a viable and economical method to significantly extend the lean operating limit and thereby improve performance and reduce emissions. Drawbacks of hydrogen as a fuel source, however, include lower power density due to a lower heating value per unit volume as compared to CNG, and susceptibility to pre-ignition and engine knock due to wide flammability limits and low minimum ignition energy. Combining hydrogen with CNG, however, overcomes more » the drawbacks inherent in each fuel type. Objectives of the current study were to evaluate the feasibility of using blends of hydrogen and natural gas as a fuel for conventional natural gas engines. The experiment and data analysis included evaluation of engine performance, efficiency, and emissions along with detailed in-cylinder measurements of key physical parameters. This provided a detailed knowledge base of the impact of using hydrogen/natural gas blends. A four-stroke, 4.2 L, V-6 naturally aspirated natural gas engine coupled to an eddy current dynamometer was used to measure the impact of hydrogen/natural gas blends on performance, thermodynamic efficiency and exhaust gas emissions in a reciprocating four stroke cycle engine. The test matrix varied engine load and air-to-fuel ratio at throttle openings of 50% and 100% at equivalence ratios of 1.00 and 0.90 for hydrogen percentages of 10%, 20% and 30% by volume. In addition, tests were performed at 100% throttle opening, with an equivalence ratio of 0.98 and a hydrogen blend of 20% to further investigate CO emission variations. Data analysis indicated that the use of hydrogen/natural gas fuel blend penalizes the engine operation with a 1.5 to 2.0% decrease in torque, but provided up to a 36% reduction in CO, a 30% reduction in NOX, and a 5% increase in brake thermal efficiency. These results concur with previous results published in the open literature. Further reduction in emissions can be obtained by retarding the ignition timing. « less

Experimental and Computational Studies on Gasoline HCCI Combustion Control Using Injection Strategies

Abstract: Homogeneous Charge Compression Ignition (HCCI) has challenges of ignition control. In this paper, HCCI ignition timing and combustion rate were controlled by two-stage direct injection (TSDI) strategies on a four-stroke gasoline HCCI engine. TSDI strategy was proposed to solve the two major problems of HCCI application-ignition control and load extension. Both simulation and experiments were carried out on a gasoline HCCI engine with negative valve overlap (NVO). An engine model with detailed chemical kinetics was established to study the gas exchange process and the direct injection strategy in the gasoline HCCI engine with TSDI and NVO. Simulation results were compared with experiments and good agreement was achieved. The simulated and experimental results provided a detailed insight into the processes governing ignition in the HCCI engine. Using TSDI, the fuel concentration, temperature as well as chemical species can be controlled. The effects of different injection parameters, such as split injection ratio and start-of-injection (SOI) timing, were studied. The experimental results indicate that, two-stage direct injection is a practical technology to control the ignition timing and combustion rate effectively in four-stroke gasoline HCCI engines. Both the high load and low load limits of HCCI operation were extended.

Turbocharger configuration for an outboard motor

Abstract: A marine propulsion device is provided with a turbocharger that is located above all, or at least a majority of, the cylinders of an engine. The exhaust gases are directed to one side of the engine and the compressed air is directed to an opposite side of the engine. The turbocharger is located at a rear portion of the engine behind the crankshaft.

Pressure reactive piston for reciprocating internal combustion engine

Abstract: A pressure reactive piston for an internal combustion engine includes an axially directed central bore formed within a piston ring portion of the piston, which houses a slidably mounted crown which cooperates with the central bore to define a gas chamber which is closed off from the environment by means of a flexible gas seal interposed between the crown and the ring portion of the piston.

Control apparatus of internal combustion engine and control method of internal combustion engine

Abstract: A control apparatus of an internal combustion engine in which a plurality of cylinders is divided into a first cylinder group (1a) and a second cylinder group (1b), the internal combustion engine being able to be selectively switched between operating in a partial cylinder operation mode in which only one of the first cylinder group (1a) and the second cylinder group (1b) is operated, and operating in a full cylinder operation mode in which both the first cylinder group (1a) and the second cylinder group (1b) are operated. This control apparatus includes a supercharger (8), as well as a controller (30) that selectively starts and stops operation of the supercharger (8) depending on a load on the internal combustion engine when the internal combustion engine is to be operated in the partial cylinder operation mode.

Dual head piston engine

Abstract: A gas or diesel internal combustion engine of either a two or four stroke design uses both ends of each piston to create a combustion chamber. The piston rod rides linearly through a lower cylinder head. The lower cylinder head forms a lower combustion chamber with its own set of valves and fuel/air inlet. A second set of lower cams and camshaft operate the lower set of valves. Crankcase oil is pumped up the middle of the piston rod to an outlet in the center of the piston.

Six-stroke internal combustion engine, method of operation of such an engine and vehicle equipped with such an engine

Abstract: This six-stroke internal combustion engine is provided with injection means (121 ) adapted to inject (I3) into at least one of its cylinders (11 ) a liquid (L) containing a reductor agent and/or a precursor for a reductor agent. During the fifth and sixth strokes of a piston (13) within the cylinder (11), this reductor agent can react with NOx molecules in order to clean the gases resulting from the combustion of a fuel mixture within the cylinder.

Charge air cooler for a stroke piston combustion engine

Abstract: The intercooler (1) has a cooler housing extending from a cooler inlet to a cooler outlet along a longitudinal axis. The inlet and outlet are connected with an outlet of a diffuser and a drain valve of an internal-combustion engine, respectively, such that fresh air is introduced as supercharged air (10) from a supercharger to the intercooler by a diffuser. Cooler packets (6) cool and precipitate condensation (11) of the supercharged air. The packets are separated from each other by a draining device (12) to remove the condensation from the intercooler.