Gas Engine

Abstract

Provided is a gas engine wherein NOx concentration in exhaust gas can be maintained properly regardless of fuel gas composition. A gas engine ( 101 ) comprises a fuel gas supply regulation valve ( 45 ) for regulating fuel gas supply, an engine speed sensor ( 71 ) for detecting engine speed, an engine torque sensor ( 72 ) for detecting engine load, and a controller ( 50 ) for calculating a proper fuel gas supply and regulating the fuel gas supply regulation means to ensure the proper fuel gas supply thus calculated, wherein the controller ( 50 ), calculates the temperature difference of a combustion chamber in the combustion stroke of one combustion cycle by recognizing at least the engine speed and engine load and calculates the NOx concentration in exhaust gas based on the temperature difference, calculates a proper fuel gas supply based on the NOx concentration and regulates the fuel gas supply regulation valve ( 45 ) to ensure the proper fuel gas supply.

1 . A gas engine comprising:
 a fuel gas supply amount regulation means for regulating a fuel gas supply amount;   an engine speed detection means for detecting an engine speed;   an engine load detection means for detecting an engine load; and   a control means for calculating a proper fuel gas supply amount and regulating the fuel gas supply amount regulation means so as to ensure the proper fuel gas supply amount,   wherein the control means recognizes at least the engine speed and the engine load so as to calculate a temperature difference in a combustion chamber in a combustion stroke of one combustion cycle, calculates a NOx concentration in exhaust gas based on the temperature difference, calculates the proper fuel gas supply amount based on the NOx concentration, and regulates the fuel gas supply amount regulation means so as to ensure the proper fuel gas supply amount.   
     
     
         2 . The gas engine according to  claim 1 , further comprising:
 an air-fuel mixture temperature detection means for detecting an air-fuel mixture temperature;   an air-fuel mixture pressure detection means for detecting an air-fuel mixture pressure; and   a throttle opening detection means for detecting a throttle opening,   wherein the control means recognizes at least the engine speed, the engine load, the air-fuel mixture temperature, the air-fuel mixture pressure and the throttle opening so as to calculate a temperature difference in the combustion chamber in the combustion stroke of one combustion cycle.   
     
     
         3 . The gas engine according to  claim 1 , further comprising:
 a fuel gas temperature detection means for detecting a fuel gas temperature;   a fuel gas pressure detection means for detecting a fuel gas pressure;   an air mass flow rate detection means for detecting an air mass flow rate; and   a fuel gas supply amount detection means for detecting the fuel gas supply amount of the fuel gas supply amount regulation means,   wherein the control means recognizes at least the engine speed, the engine load, the fuel gas temperature, the fuel gas pressure, the air mass flow rate and the fuel gas supply amount so as to calculate a temperature difference in the combustion chamber in the combustion stroke of one combustion cycle.   
     
     
         4 . The gas engine according to  claim 1 , further comprising:
 an air-fuel mixture flow rate detection means for detecting an air-fuel mixture flow rate,   wherein the control means recognizes at least the engine speed, the engine load and the air-fuel mixture flow rate so as to calculate a temperature difference in the combustion chamber in the combustion stroke of one combustion cycle.   
     
     
         5 . The gas engine according to  claim 1 , further comprising:
 an air-fuel mixture temperature detection means for detecting an air-fuel mixture temperature;   an air-fuel mixture pressure detection means for detecting an air-fuel mixture pressure;   a throttle opening detection means for detecting a throttle opening;   a cylinder pressure detection means for detecting a cylinder pressure in the cylinder; and   an exhaust gas temperature detection means for detecting an exhaust gas temperature,   wherein, instead of calculating the NOx concentration of the exhaust gas based on the temperature difference, the control means recognizes at least the engine speed, the engine load, the air-fuel mixture temperature, the air-fuel mixture pressure, the throttle opening, the cylinder pressure in the cylinder and the exhaust gas temperature so as to calculate a maximum temperature in the combustion chamber in the combustion stroke of one combustion cycle, and calculates the NOx concentration of the exhaust gas based on the maximum temperature.