Gas-fired engine

Abstract

A gas-fired engine which supplies high-pressure liquefied gas (e.g., LNG) as fuel by a reciprocating pump. A gas fuel supply device includes: a reciprocating pump driven by a hydraulic motor to boost an introduced liquefied gas pressure to a desired pressure and discharge the liquefied gas; a hydraulic oil introduction line that introduces a portion of high-pressure hydraulic oil from a hydraulic oil line and supplies the high-pressure hydraulic oil to the hydraulic motor; a hydraulic oil return line that returns the high-pressure hydraulic oil to the hydraulic oil line; a heating unit that heats and gasifies the boosted liquefied gas; a control section that adjusts a rotational speed of the hydraulic motor to maintain constant a gas fuel outlet pressure of the heating unit; and an engine inlet gas pressure-reducing valve that regulates a gas fuel pressure injected into a combustion chamber.

1 . A gas-fired engine for a high-pressure gas injection engine comprising an electronic control unit that drives an engine by controlling high-pressure hydraulic oil by a controller and an electromagnetic valve, and a gas fuel supply device that boosts a pressure of liquefied gas as fuel gas to a high pressure and performs supply into a combustion chamber by injection,
 wherein the gas fuel supply device includes:   a reciprocating pump that is driven by a hydraulic motor to boost a pressure of liquefied gas introduced thereto to a desired pressure and discharge the liquefied gas;   a hydraulic oil introduction line that introduces a portion of the high-pressure hydraulic oil from a hydraulic oil line of the electronic control unit, supplies the high-pressure hydraulic oil to the hydraulic motor, and thereby drives the hydraulic motor;   a heating unit that heats and gasifies the boosted liquefied gas supplied from the reciprocating pump; and   a control section that adjusts a rotational speed of the hydraulic motor by controlling oil supplied from the hydraulic pump to maintain constant a gas fuel outlet pressure of the heating unit.   
     
     
         2 . The gas-fired engine according to  claim 1 , wherein the rotational speed of the hydraulic motor is controlled by adjusting a discharge rate of a hydraulic pump that supplies the high-pressure hydraulic oil to the electronic control unit. 
     
     
         3 . A gas-fired engine for a high-pressure gas injection engine comprising a gas fuel supply device that boosts a pressure of liquefied gas as fuel gas to a high pressure and performs supply into a combustion chamber by injection,
 wherein the gas fuel supply device includes:   a reciprocating pump that is driven by a hydraulic motor to boost a pressure of liquefied gas introduced thereto to a desired pressure and discharge the liquefied gas;   a hydraulic pump unit that supplies a driving hydraulic pressure to the hydraulic motor from a hydraulic pump driven by a rotating shaft of an exhaust turbine, the exhaust turbine being operated by extracting a portion of exhaust gas from an engine exhaust static-pressure pipe;   a heating unit that heats and gasifies the boosted liquefied gas supplied from the reciprocating pump; and   a control section that adjusts a rotational speed of the hydraulic motor by controlling oil supplied from the hydraulic pump to maintain constant a gas fuel outlet pressure of the heating unit.   
     
     
         4 . The gas-fired engine according to  claim 3 , further comprising an engine inlet gas pressure reducing valve that regulates a pressure of gas fuel to be injected into the combustion chamber. 
     
     
         5 . A gas-fired engine for a high-pressure gas injection engine comprising a turbocharger, and a gas fuel supply device that boosts a pressure of liquefied gas as fuel gas to a high pressure and preforms supply into a combustion chamber by injection,
 wherein the gas fuel supply device includes:   a reciprocating pump that is driven by a hydraulic motor to boost a pressure of liquefied gas introduced thereto to a desired pressure and discharge the liquefied gas;   a hydraulic pump unit that supplies a driving hydraulic pressure to the hydraulic motor from a hydraulic pump driven by a rotating shaft of the turbocharger;   a heating unit that heats and gasifies the boosted liquefied gas supplied from the reciprocating pump; and   a control section that adjusts a rotational speed of the hydraulic motor by controlling oil supplied from the hydraulic pump to maintain constant a gas fuel outlet pressure of the heating unit.   
     
     
         6 . The gas-fired engine according to  claim 5 , further comprising an engine inlet gas pressure reducing valve that regulates a pressure of gas fuel to be injected into the combustion chamber. 
     
     
         7 . The gas-fired engine according to  claim 3 , wherein in the gas fuel supply device, the hydraulic pump is a variable capacity pump, and the control section adjusts the rotational speed of the hydraulic motor by variable capacity control of the hydraulic pump to maintain constant the gas fuel outlet pressure. 
     
     
         8 . The gas-fired engine according to  claim 4 , wherein in the gas fuel supply device, the hydraulic pump is a variable capacity pump, and control section adjusts the rotational speed of the hydraulic motor by variable capacity control of the hydraulic pump to maintain constant the gas fuel outlet pressure. 
     
     
         9 . The gas-fired engine according to  claim 5 , wherein in the gas fuel supply device, the hydraulic pump is a variable capacity pump, and the control section adjusts the rotational speed of the hydraulic motor by variable capacity control of the hydraulic pump to maintain constant the gas fuel outlet pressure. 
     
     
         10 . The gas-fired engine according to  claim 6 , wherein in the gas fuel supply device, the hydraulic pump is a variable capacity pump, and the control section adjusts the rotational speed of the hydraulic motor by variable capacity control of the hydraulic pump to maintain constant the gas fuel outlet pressure. 
     
     
         11 . The gas-fired engine according to  claim 3 , wherein in the gas fuel supply device, the hydraulic pump is a constant capacity pump, and the control section adjusts the rotational speed of the hydraulic motor by rotation number control of the exhaust turbine to maintain constant the gas fuel outlet pressure. 
     
     
         12 . The gas-fired engine according to  claim 4 , wherein in the gas fuel supply device, the hydraulic pump is a variable capacity pump, and the control section adjusts the rotational speed of the hydraulic motor by variable capacity control of the hydraulic pump to maintain constant the gas fuel outlet pressure.