Compression ignition internal combustion engine

Abstract

It is an object of the present invention to provide a compression ignition internal combustion engine capable of making compatible an increase in compression self-ignition operating area with an optimum output torque control in the operating area and also smoothly switching between a self-ignition combustion and a spark ignition combustion. The compression ignition internal combustion engine operates by switching between the spark ignition combustion using an ignition device and the compression ignition combustion which self-ignites a mixture by piston compression. Variable valve mechanisms ( 15 a, 15 b ) vary at least one of the valve timings and valve lifts of an intake valve and an exhaust valve. Intake air regulating means ( 7; 30; 32; 40, 42 ) vary the amount of air intake into a combustion chamber on the upstream side of a combustion chamber inlet of the compression ignition internal combustion engine. Control means ( 1 ) controls the variable valve mechanisms ( 15 a, 15 b ) and the intake air regulating means ( 7; 30; 32; 40, 42 ) during the compression ignition combustion so as to perform the compression ignition combustion.

1 . A compression ignition internal combustion engine for operating by switching a spark ignition combustion using an ignition device and a compression ignition combustion for self-igniting a mixture by piston compression comprising: 
 variable valve mechanisms ( 15   a,    15   b ) for varying at least one of valve timings and valve lifts of an intake valve and an exhaust valve;    intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) for varying an amount of air intake into a combustion chamber on an upstream side of a combustion chamber inlet of the compression ignition internal combustion engine; and    control means ( 1 ) for controlling said variable valve mechanisms and said intake air regulating means during a compression ignition combustion so as to perform a compression ignition combustion.    
     
     
         2 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ) so as to reduce valve lifts of said exhaust valve during a compression ignition combustion.  
     
     
         3 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ) so as to reduce an opening time of said exhaust valve during a compression ignition combustion.  
     
     
         4 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) decides an amount of fuel injection according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine, calculates a target amount of intake air from said decided amount of fuel injection so as to attain a target air-fuel ratio and controls said variable valve mechanisms ( 15   a,    15   b ) and said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) so that the amount of air intake into said combustion chamber becomes the target amount of air.  
     
     
         5 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) decides an amount of fuel injection according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine, calculates a target amount of intake air from said decided amount of fuel injection so as to attain a target air-fuel ratio and controls said variable valve mechanisms ( 15   a,    15   b ) and said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) so that an ignition timing becomes a target ignition timing.  
     
     
         6 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) decides a target amount of intake air according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine and controls said variable valve mechanisms ( 15   a,    15   b ) and said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) so that an air-fuel ratio becomes a target air-fuel ratio.  
     
     
         7 . A compression ignition internal combustion engine according to  claim 6 , wherein said control means ( 1 ) further performs feedback control so that an ignition timing becomes a target ignition timing.  
     
     
         8 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) operates said intake valve or said exhaust valve according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine and controls fuel injecting means ( 11 ) and said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) so that an air-fuel ratio becomes a target air-fuel ratio.  
     
     
         9 . A compression ignition internal combustion engine according to  claim 8 , wherein said control means ( 1 ) further performs feedback control so that an ignition timing becomes a target ignition timing.  
     
     
         10 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ), said fuel injecting means ( 11 ) and said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of the vehicle incorporating said compression ignition internal combustion engine so that an air-fuel ratio becomes a target air-fuel ratio.  
     
     
         11 . A compression ignition internal combustion engine according to  claim 10 , wherein said control means ( 1 ) performs feedback control so that an ignition timing becomes a target ignition timing.  
     
     
         12 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) operates said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine and controls said fuel injecting means ( 11 ) and said variable valve mechanisms ( 15   a,    15   b ) so that an air-fuel ratio becomes a target air-fuel ratio.  
     
     
         13 . A compression ignition internal combustion engine according to  claim 12 , wherein said control means ( 1 ) further performs feedback control so that an ignition timing coincides with a target ignition timing.  
     
     
         14 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ) so that the intake valve has small lifts and the closing timing of the intake valve is advanced during an operating condition is in a low-speed and low-load state,.  
     
     
         15 . A compression ignition internal combustion engine according to  claim 14 , wherein said control means ( 1 ) maximizes an amount of intake air by said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) while keeping an internal EGR rate constant.  
     
     
         16 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ) so that an amount of intake air into said combustion chamber is increased as an engine load increases in an operating area by said compression ignition combustion.  
     
     
         17 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ) or said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) so that a temperature of a mixture inside said combustion chamber increases at the start of a compression process as an engine speed increases in an operating area by said compression ignition combustion so as to increase an internal EGR rate.  
     
     
         18 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls so that an amount of fuel injection increases as an engine speed increases in an operating area by said compression ignition combustion.  
     
     
         19 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means ( 1 ) controls so that an air-fuel ratio approaches a theoretical air-fuel ratio as an engine speed increases in an operating area by said compression ignition combustion.  
     
     
         20 . A compression ignition internal combustion engine according to  claim 1 , wherein when said compression ignition combustion is switched to said spark ignition combustion, said control means ( 1 ) controls said variable valve mechanisms ( 15   a,    15   b ) so that an internal EGR rate is reduced compared with that during said compression ignition combustion.  
     
     
         21 . A compression ignition internal combustion engine according to  claim 20 , wherein when said compression ignition combustion is switched to said spark ignition combustion, said control means ( 1 ) controls said intake air regulating means ( 7 ;  30 ;  32 ;  40 ,  42 ) so that an amount of intake air changes continuously.  
     
     
         22 . A compression ignition internal combustion engine according to  claim 1 , wherein said intake air regulating means ( 30 ) is provided in a flow channel that bypasses an intake path.  
     
     
         23 . A compression ignition internal combustion engine according to  claim 1 , wherein said intake air regulating means ( 32 ) is provided by a supercharger which supplies supercharged air into said combustion chamber and said control means controls the amount of air to be supplied by controlling the supercharging pressure of this supercharger.  
     
     
         24 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means controls for switching said spark ignition combustion and said compression ignition combustion according to engine operating conditions of this compression ignition internal combustion engine, a vehicle driving condition of said vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine.  
     
     
         25 . A compression ignition internal combustion engine according to  claim 24 , wherein when an accelerator opening is equal to or greater than a predetermined value or when a vehicle acceleration is equal to or greater than a predetermined value, said engine is operated by said spark ignition combustion.  
     
     
         26 . A compression ignition internal combustion engine according to  claim 24 , wherein when an accelerator opening is equal to or greater than a predetermined value or when the vehicle speed is equal to or greater than a predetermined value, said engine is operated by said spark ignition combustion.  
     
     
         27 . A compression ignition internal combustion engine according to  claim 24 , wherein when a vehicle speed is equal to or greater than a predetermined value and a brake depressing force is equal to or greater than a predetermined value, engine operation by said compression ignition combustion is prohibited.  
     
     
         28 . A compression ignition internal combustion engine according to  claim 24 , wherein when a cooling water temperature and a intake air temperature are equal to or lower than a predetermined value, said engine is operated by said spark ignition combustion.  
     
     
         29 . A compression ignition internal combustion engine according to  claim 28 , wherein when an exhaust temperature is equal to or higher than a predetermined value, engine operation is switched to operation by said compression ignition combustion.  
     
     
         30 . A compression ignition internal combustion engine according to  claim 1 , wherein said control means prohibits engine operation by said compression ignition combustion according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of the vehicle incorporating said compression ignition internal combustion engine.  
     
     
         31 . A compression ignition internal combustion engine for operating by switching a spark ignition combustion using an ignition device and a compression ignition combustion for self-igniting a mixture by piston compression, wherein a switching engine operation between said spark ignition combustion and said compression ignition combustion according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating said compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine.  
     
     
         32 . A compression ignition internal combustion engine according to  claim 31 , wherein when an accelerator opening is equal to or greater than a predetermined value or a vehicle acceleration is equal to or greater than a predetermined value, engine operation is performed by said spark ignition combustion.  
     
     
         33 . A compression ignition internal combustion engine according to  claim 31 , wherein when an accelerator opening is equal to or greater than a predetermined value or a vehicle speed is equal to or greater than a predetermined value, engine operation is performed by said spark ignition combustion.  
     
     
         34 . A compression ignition internal combustion engine according to  claim 31 , wherein when a vehicle speed is equal to or greater than a predetermined value and a brake depressing force is equal to or greater than a predetermined value, engine operation by said compression ignition combustion is prohibited.  
     
     
         35 . A compression ignition internal combustion engine according to  claim 31 , wherein when a cooling water temperature and a intake air temperature are equal to or lower than a predetermined value, engine operation is performed by said park ignition combustion.  
     
     
         36 . A compression ignition internal combustion engine according to  claim 35 , wherein when an exhaust temperature is equal to or higher than a predetermined value, engine operation is switched to operation by said compression ignition combustion.  
     
     
         37 . A compression ignition internal combustion engine for operating switching a spark ignition combustion using an ignition device and a compression ignition combustion for self-igniting mixture by piston compression, wherein engine operation by said compression ignition combustion is prohibited according to engine operating conditions of said compression ignition internal combustion engine, a vehicle driving condition of a vehicle incorporating this compression ignition internal combustion engine and an intention of a driver of said vehicle incorporating said compression ignition internal combustion engine.  
     
     
         38 . A compression ignition internal combustion engine according to  claim 37 , wherein when an accelerator opening is equal to or greater than a predetermined value or a vehicle acceleration is equal to or greater than a predetermined value, engine operation is performed by said spark ignition combustion.  
     
     
         39 . A compression ignition internal combustion engine according to  claim 37 , wherein when an accelerator opening is equal to or greater than a predetermined value or a vehicle speed is equal to or greater than a predetermined value, engine operation is performed by said spark ignition combustion.  
     
     
         40 . A compression ignition internal combustion engine according to  claim 37 , wherein when a vehicle speed is equal to or greater than a predetermined value and a brake depressing force is equal to or greater than a predetermined value, engine operation by said compression ignition combustion is prohibited.  
     
     
         41 . A compression ignition internal combustion engine according to  claim 37 , wherein when a cooling water temperature and a intake air temperature are equal to or lower than a predetermined value, engine operation is performed by said spark ignition combustion.  
     
     
         42 . A compression ignition internal combustion engine according to  claim 41 , wherein when an exhaust temperature is equal to or higher than a predetermined value, engine operation is switched to operation by said compression ignition combustion.