Mitsubishi Heavy Industries Limited

Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.

Hideki Nishio

Hajime Suzuki

Yuuichi Shimizu

Michiyasu Ishida

Hirotoshi Kitagawa

Hiroshi Yoshizumi

Junnosuke Andou

A knocking control method in a power generation system () which includes a gas engine () including a plurality of air cylinders () and a knocking detection unit () configured to detect knocking in each of the air cylinders (). The knocking control method includes a first control step of delaying an ignition timing for at least one of the air cylinders () when the knocking detection unit () has detected knocking; a second control step of reducing an amount of gas supplied to at least one of the air cylinders () when the knocking has not been eliminated by the first control step; and a third control step of shutting off supply of a gas to any of the air cylinders () in which the knocking has occurred.

Knocking control method

In an embodiment, a combustion control device for an engine includes: a knocking determination unit to determine occurrence of knocking of each of the cylinders; a knocking reduction unit to halt or reduce supply of gas to a cylinder in which the knocking is occurring and reduce supply of the gas to other cylinders in which the knocking is not occurring; a first recovery unit configured to recover a state where the gas is at least reduced in the cylinder in which the knocking is occurring; and a second recovery unit configured to recover a state where the gas is reduced in other cylinders within which knocking is not occurring. In embodiments, a recovery time of the first recovery unit is shorter than a recovery time of the second recovery unit, and prioritizing recovery of the cylinder in which the knocking is occurring.

Combustion control device for gas engine

Embodiments may provide a starting device for a gas internal combustion engine whereby non-combusted gas accumulating in the gas internal combustion engine and an exhaust channel is discharged before ignition startup of the gas internal combustion engine and abnormal combustion of the gas internal combustion engine is prevented so as to improve safety, breakage prevention, durability and reliability. A starting device of a gas internal combustion enginehaving an air starting deviceincludes a rotation-speed detection unit of the gas internal combustion engine, a compressed-air introduction unitfor supplying compressed air to each of cylinders according to an order of an ignition timing of the gas internal combustion engine, a compressed-air supply unitfor supplying the compressed air to the compressed-air introduction unit, and a control deviceincluding a cumulative rotation-speed setting devicewhereby an operator can set a threshold value of a cumulative rotation speed optionally, the control devicebeing configured to halt supply of the compressed air by the compressed-air supply unitif a set cumulative rotation speed is achieved on the basis of the rotation speed detected by the rotation-speed detection unit.

Starting device for gas internal combustion engine

In a gas engine provided with a gas supply pipe () branching into a supercharger-side gas supply pipe () and a cylinder-side gas supply pipe (), a supercharger-side gas adjusting valve () and a cylinder-side gas adjusting valve () for controlling flow rates of passages, when the gas concentration of the fuel gas changes, the cylinder-side gas adjusting valve is controlled first to keep the output of the gas engine constant and then the supercharger-side gas adjusting valve is controlled to achieve the fuel gas flow rate Qbased on the constant flow ratio by means of a gas supply controller (), while maintaining the flow rate ratio Q/Qat a constant value where Qis a fuel gas flow rate in the supercharger-side gas supply pipe and Qis a fuel gas flow rate in the cylinder-side gas supply pipe.

Fuel gas supply method and supply unit for gas engine

In particular embodiments, a starting device for a gas internal combustion engine whereby non-combusted gas accumulating in the gas internal combustion engine and an exhaust channel is discharged during ignition startup of the gas engine and abnormal combustion is reduced in the occurrence so as to improve safety, breakage prevention, durability and reliability. An exhaust purge device for a gas internal combustion engine, which operates using flammable gas as fuel, includes an exhaust channelforming an exhaust channel of the gas internal combustion engine, a blast pipeconnected to an upstream portion of the exhaust pipe at a first end, an exhaust purge fanconnected to a second end of the blast pipeand configured to send ambient air to the exhaust channel, and a control devicefor performing a control to drive the exhaust purge fan

Exhaust purge device for gas internal combustion engine

A controller for a gas engine includes a cycle detection unitconfigured to detect a crank angle period of a single combustion cycle of an engine including a plurality of cylinders based on a crank angle detection value inputted from a crank angle detector, a misfire detection unitconfigured to detect a misfire in a combustion chamberbased on an in-cylinder pressure detection value inputted from the in-cylinder pressure detector, and a simultaneous misfire determination unitconfigured to determine a simultaneous misfire of more than one cylinder when a total number of cylinders where the misfire is detected in the single combustion cycle by the misfire detection unitis not less than a preset threshold value of a cylinder number. The fuel gas to all of the cylinders is shut off when the simultaneous misfire of more than one cylinder in the single combustion cycle is determined by the simultaneous misfire determination unit

Controller and control method for gas engine

An object is to provide a method and a system of controlling a load during misfire of an engine, whereby additional stress on a crank shaft is calculated from torsional vibration of the crank shaft to obtain an output limit rate, and an operation output of an engine is controlled on the basis of the output limit rate. The method includes: a first step of calculating additional stress on a crank shaft on the basis of a vector sum of crank-shaft torsional vibration vibratory force when the misfire is detected; a second step of determining whether the calculated additional stress on the crank shaft is less than an allowable stress with respect to the crank shaft; a third step of controlling an operation output of the engine to be reduced by a predetermined amount and returning to the first step if the calculated additional stress is greater than the allowable stress and obtaining an output limit rate by calculating the additional stress on the crank shaft if it is determined that the calculated additional stress on the crank shaft is less than the allowable stress with respect to the crank shaft; and a fourth step of controlling the operation output of the engine on the basis of the output limit rate.

Method and system for load control during misfire of engine

An air supply device of a gas engine having a turbocharger includes a first intake passage configured to guide the mixture of outdoor air and unpurified gas into the turbocharger, a second intake passage configured to guide indoor air into the turbocharger, a filter configured to remove a solid impurity in the unpurified gas which is disposed in the first intake passage, a first damper capable of opening and closing the first intake passage disposed on the downstream side of the filter in the first intake passage, a heating unit for heating the indoor air disposed in the second intake passage, a second damper capable of opening and closing the second intake passage disposed on the downstream side of the heating unit in the second intake passage, and a damper control device configured to control the opening degree of each of the first and second dampers.

Air supply device of gas engine

In a gas enginethat uses a gas having a lower specific gravity than air and has a pre-mixing device before a turbocharger, a pre-mixed gas mixture compressed by a turbochargeris cooled by an intercoolerlocated downstream of the turbochargerin the intake system. Condensed water produced as the gas is cooled and the pre-mixed gas mixture discharged with the condensed water are separated into condensed water, air, and fuel gas in a vapor-liquid separator. The fuel gas is returned to the intake system upstream of the turbocharger, while the condensed water is discharged to atmosphere.

Gas engine having intercooler

A gas engine includes a generator coupled to an output shaft thereof, an intake passage to which a low-concentration methane gas (VAM gas) derived from mine venting is supplied, and a gas mixing unit mixing a high-concentration methane gas (CMM gas) to the low-concentration methane gas midway along the intake passage, so that a gas mixture of the low-concentration methane gas and the high-concentration methane gas is supplied to and burnt in a combustion chamber. A turbocharger is provided in the intake passage upstream of the gas mixing unit, and in the intake passage upstream of the turbocharger, is provided a mixture ratio adjusting unit adjusting a mixture ratio of the low-concentration methane gas and the air. The temperature or flow rate of intake gas flowing into the turbocharger is kept in a constant range by an intake controller.

Gas engine

Provided is a seal air supply system including: a seal air compressorprovided separately from an exhaust gas turbine turbochargerto generate compressed air; a seal air supply passagethrough which the compressed air is supplied to a seal air supply partas seal air of the exhaust gas turbine turbocharger; and a surplus air inlet passagebifurcating from the seal air supply passageand guiding surplus air of the seal air to an outlet side of an intake gas compressorof the exhaust gas turbine turbocharger.

Seal air supply system and exhaust gas turbine turbocharger using seal air supply system

A method to control a gas engine system is disclosed, whereby the engine can be operated with an air-fuel-ratio controlled with high precision, even in using a low calorific fuel-gas that is prone to vary in calorific value; the engine system includes: In the case when the fuel-gas is of a low calorific value or where the output of the engine is high, a part of the fuel-gas is supplied to the engine through the first and second lines. The mixer forms a mixture of a prescribed mixing ratio that is leaner than a lower limit of flammability of the fuel-gas, while the remaining fuel-gas through the first line is supplied to the mixture just before each cylinder so that a final prescribed air fuel ratio is formed. In the case when the calorific value of the fuel-gas is high, or of high engine output, the whole fuel-gas can be supplied only through the first gas line.

Method to control a gas engine system thereof

In a gas engine system, air fed through a turbocharger is mixed with fuel gas flowing through a fuel gas supply line and supply into a combustion chamber is controlled. In case that the fuel gas has a low calorie or the engine output power is high, a portion of the fuel gas is diverged from the fuel gas supply line, and the flow rate thereof is set to a constant rate less than that of the diverged side fuel gas. The diverging fuel gas is fed into the combustion chamber through a divergence control valve while the remainder of the fuel gas is fed into the fuel flow control valve. In case that the fuel gas has a high calorie or the engine output power is low, the divergence control valve is closed so as to feed the fuel gas only into the gas supply main pipe.

Method to control a gas engine and a gas engine system thereof

What is disclosed is a micro-pilot injection ignition type gas engine, whereby an air fuel ratio control in starting the engine is executed with enhanced precision, by means of introducing skip-firing intermittent operations which reflect the engine operation conditions, while an idling time span can be shortened or omitted. The engine includes: a gas valve that opens and closes a fuel-gas passage in front of each cylinder, so as to arbitrarily control the throat area as well as the opening-closing time span of the gas valve; an engine speed detecting unit to detect the engine speed; a combustion diagnosis unit to detect an engine combustion state through a cylinder pressure distribution along elapsed time, as to each cylinder; an opening-closing control unit as to the gas valve, so as to control the intermittent opening-closing of the gas valve according to the levels of the detected engine speed as well as the cylinder pressure distribution; whereby, in starting the engine, the intermittent opening-closing of the gas-valve enables at least one skip-firing mode that brings an enhanced fuel-supply pressure-pulsation with which a relatively large amount of fuel-gas is supplied per engine cycle with firing so that the air fuel-gas ratio of each cylinder reaches a prescribed target value.

Growing community of inventors

Tokyo, Japan

Hideki Nishio