Internal combustion engine

Abstract

According to the invention, noise of an internal combustion engine is reduced by dynamically correcting the moment of injection when the engine is in the transient mode.

1 - 20 . (canceled) 
   
   
       21 . A method of operating an internal combustion engine which is switched at least between a first and a second mode of operation as a function of at least one characteristic engine operation parameter, involving the following steps:
 selecting at least one characteristic engine operation parameter,   associating value ranges with each engine operation parameter, at least one first value range being associated with the first mode of operation and at least one second value range being associated with the second mode of operation,   comparing actual values of the selected characteristic engine operation parameters with the value ranges, and   switching to the second mode of operation or remaining in the second mode of operation when all the selected characteristic engine operation parameters lie within the second value range.   
   
   
       22 . The method according to  claim 21 , wherein the engine is switched to the first mode of operation or remains in the first mode of operation when at least one actual value of a selected characteristic engine operation parameter lies within the first value range. 
   
   
       23 . The method according to  claim 21 , wherein at least one threshold value for switching between the modes of operation is associated with each selected characteristic engine operation parameter, the first and the second range of values being separated by said threshold value. 
   
   
       24 . The method according to  claim 21 , wherein at least one characteristic engine operation parameter is selected from a group comprising engine speed, engine load, engine coolant temperature, atmospheric pressure, temperature of an exhaust gas after-treatment system, exhaust gas temperature upstream of an exhaust gas after-treatment system, exhaust gas temperature downstream of the exhaust gas after-treatment system, speed of an engine speed change, speed of the engine load change and actual transmission ratio of a driving train. 
   
   
       25 . The method according to  claim 21 , wherein the internal combustion engine is operated in the first mode of operation with conventional diesel combustion and in the second mode of operation with alternative diesel combustion. 
   
   
       26 . The method according to  claim 21 , wherein a predetermined fixed value is selected for at least one threshold value. 
   
   
       27 . The method according to  claim 21 , wherein at least one threshold value of at least one selected characteristic engine operation parameter is determined as a function of at least one other engine operation parameter. 
   
   
       28 . The method according to  claim 21 , wherein at least one threshold value has a hysteresis. 
   
   
       29 . A method of operating an internal combustion engine which is switched at least between a first and a second mode of operation as a function of at least one characteristic engine operation parameter, wherein switching occurs as a function of a measured and/or calculated temperature before and/or after the exhaust after-treatment system. 
   
   
       30 . A method of operating an internal combustion engine comprising the following steps:
 determining a desired value for injection timing and/or a combustion situation,   determining a desired value for a ratio fresh air mass to inert gas mass inside a cylinder and/or for an air/fuel ratio in an exhaust,   measuring or computing an actual value for a ratio fresh air mass to inert gas mass inside the cylinder and/or for the air/fuel ratio in the exhaust,   calculating a difference between the desired value and the actual value of the ratio fresh air mass to inert gas mass inside the cylinder or of the air/fuel ratio in the exhaust, and   correcting a desired value of injection timing or the combustion situation as a result of the difference between the desired value and the actual value of the ratio fresh air mass to inert gas mass in the cylinder or of the air/fuel ratio in the exhaust.   
   
   
       31 . The method according to  claim 30 , wherein the desired value for injection timing and/or for the combustion situation is corrected by being advanced if the actual value for the ratio fresh air mass to inert gas mass inside the cylinder and/or the air/fuel ratio in the exhaust is smaller than the desired value for the ratio fresh air mass to inert gas mass or the air/fuel ratio in the exhaust. 
   
   
       32 . The method according to  claim 30 , wherein the desired value for injection timing and/or for the combustion situation is corrected by being retarded if the actual value for the ratio fresh air mass to inert gas mass inside the cylinder and/or the air/fuel ratio in the exhaust is greater than the desired value for the ratio fresh air mass to inert gas mass or the air/fuel ratio in the exhaust. 
   
   
       33 . The method according to  claim 30 , wherein the desired value for injection timing is determined by simple control—without feedback on the actual combustion situation. 
   
   
       34 . The method according to  claim 30 , wherein injection timing is determined by regulation from the difference between the desired value of the combustion situation and the actual value of the combustion situation—using a combustion regulator with feedback on the actual combustion situation.