126 results about "Hcci combustion" patented technology

A liquid primary fuel is ignited by HCCI with the assistance of the early injection of a liquid pilot fuel. Pilot fuel injection and/or ignition are preferably controlled so as to permit the injected pilot fuel to become thoroughly distributed through and mixed with the primary fuel/air charge in the combustion chamber and vaporized prior to ignition. Pilot fuel having a lower autoignition temperature will be ignited by compression ignition, followed by the ignition of the homogeneous mixture of the primary fuel and air. HCCI combustion of the primary fuel is facilitated by 1) selection of the properties of the primary and pilot fuels and 2) obtaining a homogenous mixture of primary fuel and air by injecting primary fuel into the engine's intake air stream in the form of finely atomized droplets having a mean diameter in the micron range.

The controller includes combustion mode switching means for decreasing an exhaust gas temperature in the spark ignition combustion immediately before the combustion mode switching based on an estimated exhaust gas temperature immediately before the combustion mode switching, or for decreasing an EGR amount in the HCCI combustion immediately after the combustion mode switching.

An engine (10, 100) utilizes “regular EGR cooling” when operating in HCCI mode within a low load range and “enhanced EGR cooling” that allows the engine to continue to operate in HCCI mode when engine load increases beyond the low load range. When engine load increases to a high load range, the combustion mode changes over to conventional diesel combustion, and exhaust gas recirculation reverts to “regular EGR cooling”. In a first embodiment, cooling is provided by two heat exchangers, one being a regular EGR cooler always used when cooling is needed and the other, an enhancing EGR cooler that is selectively used. In a second embodiment, cooling is also provided by two heat exchangers, one being an EGR cooler through which liquid coolant always flows when cooling is needed, and the other being a radiator used selectively to cool the liquid coolant before it enters the EGR cooler.

An engine (10) utilizes “regular EGR cooling” when operating in HCCI mode at loads within a low load range (56, 58, 60) and “enhanced EGR cooling” that allows the engine to continue to operate in HCCI mode when engine load increases beyond loads in the low load range (64, 66, 68). When engine load increases further to a point where it enters a high load range, the combustion mode changes over to conventional diesel combustion, and exhaust gas recirculation reverts to “regular EGR cooling” (70, 72, 74).

A compression ignition engine (60) has a control system (66) for processing data, one or more combustion chambers (62), and fuel injectors (64) for injecting fuel into the chambers. The control system controls fueling using a result of the processing of certain data, such as engine speed and engine load, to select one of three fueling modes (HCCI+RVT, HCCI+VVT, CD+RVT) for operating the engine. When the result of the processing selects the HCCI+RVT mode, intake valves operate with regular valve timing (RVT), and the engine is fueled to cause homogeneous-charge compression-ignition (HCCI) combustion. When the result of the processing selects the HCCI+VVT mode, intake valve timing is changed relative to RVT, and the engine is fueled to cause HCCI combustion. When the result of the processing selects the CD+RVT mode, the intake valves operate with RVT, and the engine is fueled to cause CD combustion.

The invention discloses an energy-saving ultra-low discharge dual-mode uniform engine, based on variable-throttle device, wherein a cylinder cover is a variable-throttle cylinder cover arranged with two throttle strike continuous changers and a variable-throttle phase device whose frame is arranged with a chain tooth around and connected with a crank of the engine via chain. The inventive engine can completely utilize the high-effect energy-saving ultra-low discharge character of uniform HCCI burning mode to switch between spark burning SI and HCCI burning mode according to working conditions, to save energy and ultra-low discharge. And the variable-throttle device can realize the control on different burning modes, and switch between two modes.

An engine operating in a spark-assisted homogeneous charge compression ignition mode during warm-up cycle is controlled using settings determined by interpolating between cold engine temperature settings fully warmed-up engine temperature settings.

The invention discloses a model-based decoupling and disturbance-rejection control method for HCCI. The method comprises model-based decoupling control, active disturbance rejection control (ADRC), feed-forward control and self-adaptation compensation control for valve mechanism action delay. The method comprises the steps of designing a decoupling compensator on the basis of a control model of the HCCI, and converting an HCCI system into a plurality of independent single-input single-output (SISO) systems; conducting inversion on transfer functions of all SISO systems to obtain a feed-forward controller; designing ADRC controllers for all SISO systems respectively, and observing and compensating deviations of the model and random disturbance of the outside in real time; and estimating the action delay of a valve mechanism in real time, actively delaying an oil injection action, and obtaining the response speed which is the same as that of the valve mechanism. By the aid of the method, the modeling burden of the HCCI control model and the standard workload of controller parameters can be reduced greatly, the robustness for engine working condition variations is high, and the ignition process control is stable.

A method of controlling homogenous charge compression ignition (HCCI) combustion timing and pressure rise rate. A constant volume air pump, such as a supercharger, is equipped to provide a variable amount of fresh air to a turbocharger. The also turbocharger drives a high pressure exhaust gas recirculation (EGR) loop. The fresh air intake and the EGR ratio are independently controlled. This combination of hardware allows for good control of combustion timing by providing for EGR variations without undue effect from varying oxygen concentration. Additionally, by adjusting the EGR ratio, the pressure rise rate during combustion can be controlled to reduce combustion noise.

A double fuel homogeneous compression ignition/quasi-homogeneous compression ignition combustion system is composed of a diesel tank, a gas tank, a high pressure common track spray device, a gas channel spray device, cooled waste gas recycle device and an electronic control unit, among which, the diesel tank and the gas tank are connected with the engine via the high pressure spray device and gas recycle device is connected with the inlet and discharge tubes of the engine, the input of the engie work state output by the engine and the output is connected with the common track spray device, gas channel device and the cooled waste gas recycle device.

A method for controlling combustion in a spark-ignition direct-injection internal combustion engine includes monitoring an engine operating mode and an ambient parameter, determining a deviation of the ambient parameter relative to a nominal ambient parameter, determining a nominal desired engine operation parameter based on engine speed and load, determining and adjusted desired engine operation parameter based on the nominal desired engine operation parameter and said deviation of the ambient parameter, and controlling the engine based on the engine operating mode and one of the nominal desired engine operation parameter and adjusted desired engine operation parameter.

A compression ignition engine (20) has a control system (26) for processing data, one or more combustion chambers (22), and fuel injectors (24) for injecting fuel into the chambers. The control system controls fueling using a result of the processing of certain data, such as engine speed and engine load, to select one of three fueling modes (HCCI, HCCI+CD, CD) for operating the engine. When the result of the processing selects the HCCI mode, the engine is fueled to cause homogeneous-charge compression-ignition (HCCI) combustion in all combustion chambers. When the result of the processing selects the HCCI+CD mode, the engine is fueled to cause HCCI combustion in some chambers and CD (conventional diesel) combustion in the remaining chambers. When the result of the processing selects the CD mode, the engine is fueled to cause CD combustion in all chambers.

An ECU switches a combustion mode of an HCCI engine from HCCI combustion to spark ignition combustion. The ECU executes the following operations a) and b) before switching an intake lift amount from a first intake lift amount to a second intake lift amount:

a): switching an exhaust lift amount from a first exhaust lift amount to a second exhaust lift amount while ensuring an internal EGR amount, and

b): delaying a closing timing of an exhaust valve so as to reduce the internal EGR amount after switching the exhaust lift amount from the first exhaust lift amount to the second exhaust lift amount.

In an engine in which a first portion of engine cylinders operate in HCCI combustion mode only and a second portion of engine cylinders operate in SI combustion mode only, two EGR ducts and valves are provided: a first EGR duct adapted to provide flow from an exhaust of HCCI engine cylinders to an intake of HCCI cylinders; a first EGR valve disposed in the first EGR duct; a second EGR duct adapted to provide flow from an exhaust of SI cylinders to an intake of HCCI cylinders via a first EGR valve; and a second EGR valve disposed in the second EGR duct. By adjusting the EGR valves, the intake temperature to HCCI cylinders is controlled. During cold start, the second EGR valve is opened to pull SI exhaust through HCCI cylinders for the purpose of preheating HCCI cylinders.

The present invention relates to a device expanding the load range of a compression ignition gasoline engine and a method thereof. The device comprises a cylinder which is respectively connected with an air inlet channel and an exhaust channel by a vale, a piston which moves up and down in the cylinder and is provided with a drop pit at the top, an electric heater plug with a heating end extended into the drop pit when the piston runs to an upper stop point, and an oil atomizer with a nozzle opposite to the drop pit when the piston runs to the upper stop point. The method has the steps as follows: the oil atomizer sprays oil respectively during an air intake stroke and a compression stroke to form delaminated mixed gas in dense and thin areas; the electric heater plug heats the mixed gas in the cylinder to form heat delamination; the area with dense gas and high temperature in the drop pit of a combustion chamber fires firstly and ignites other areas to fire accordingly. The present invention controls the dense and the thin areas to fire successively, so as to reduce the pressure increase rate in the cylinder, ensure the reliable firing and achieve the purpose of developing HCCI combustion executable high and low charge ranges at the same time.

An HCCI (homogeneous charge compression ignition) engine fire detecting and controlling method includes that a crank angle signal and a cylinder pressure signal are acquired in each working cycle of an HCCI engine, a pressure observation window with a compression top dead center is arranged, the integral value of the cylinder pressure signal in the pressure observation window is compared with a fire pressure threshold value at a finishing point of the pressure observation window, when the integral value is smaller than or equal to the fire pressure threshold value, an ECU (electronic control unit) sequentially transmits an oil recharging signal and an ignition signal to an oil injector and an ignition coil, and mixed gas in a fire cylinder is ignited in an expansion stroke. The HCCI engine fire detecting and controlling method has the advantages of simplicity, reliability, high control precision and the like, inter-circulation fluctuation of the HCCI engine can be reduced effectively, stability of combustion of a small load is improved, a running range of an HCCI combustion mode is expanded, fuel economy is improved, and HC (hydrocarbon compound) emission caused by fire is reduced.