Control system for internal combustion engine with catalyst for purifying exhaust gas

Abstract

There is provided a control system for an internal combustion engine, which aim for early warm-up of catalyst and the engine in order to control a cooling loss and a heat radiation for cooling in such a way that the warm-up of the catalyst is carried out prior to the warm-up of the engine. That is, if the temperature of the catalyst is not greater than an activation temperature, there is carried out at least one of (1) retardation control of the ignition timing, (2) stopping control of a water pump for engine cooling water, (3) lowering control of the flow rate of the cooling water, but if the temperature of the catalyst is higher than the activation temperature, there is carried out at least one of control of the water pump in accordance with a temperature of the cooling water and control of retardation of the ignition timing, until the temperature of the cooling water reaches a warm-up temperature which is a normal operation temperature of the engine.

What is claimed is:  
     
         1 . A control system for an internal combustion engine incorporating catalyst for purifying exhaust gas from the engine, characterized in that a heat transmitted from combustion gas to an engine block (cooling loss) and a heat transmitted from the engine block to cooling water (heat radiation for cooling), are controlled to effect early warm-up of the catalyst during a cold start of the engine.  
     
     
         2 . A control system for an internal combustion engine as set forth in  claim 1 , wherein the cooling loss and the heat radiation for cooling are controlled in such a way that the warm-up of the catalyst is carried out prior to the warm-up of the engine while aiming for early warm of both catalyst and engine during a cold start of the engine.  
     
     
         3 . A control system for an internal combustion engine as set forth in  claim 1  or  2 , wherein the control of the cooling loss is carried out by controlling an ignition timing, and the control of the heat radiation for cooling is carried out by controlling a flow rate of engine cooling water by means of a water pump, and if a temperature of the catalyst has not yet reach its activation temperature, the ignition timing is retarded under control so as to decrease the cooling loss while a flow rate of the engine cooling water is set to be zero or smaller than a normal flow rate so as to decrease the heat radiation for cooling.  
     
     
         4 . A control system for an internal combustion engine as set forth in any one of  claim 1  to  3 , wherein the cooling loss and the heat radiation for cooling are controlled in accordance with at least either a temperature of engine cooling water or a temperature of the catalyst.  
     
     
         5 . A control system for an internal combustion engine as set forth in any one of  claims 1  to  4 , wherein the heat radiation for cooling is controlled so as to be minimum until the temperature of the catalyst comes up to the activation temperature.  
     
     
         6 . A control system as set forth in any one of  claims 1  to  5 , the cooling loss is controlled to be maximum until the internal combustion engine is warmed up after the temperature of the catalyst reaches the activation temperature.  
     
     
         7 . A control system for an internal combustion engine comprising cooling water for cooling the engine, a circulation passage for the cooling water, a water pump for controlling a flow rate of the cooling water, and catalyst for purifying exhaust gas from the engine, characterized in that the water pump is controlled in accordance with a temperature of the catalyst.  
     
     
         8 . A control system for an internal combustion engine as set forth in  claim 7 , wherein the water pump is stopped under control if the temperature of the catalyst is not greater than an activation temperature at which the catalyst can purify the exhaust gas, and the water pump is controlled in accordance with a temperature of the cooling water after the temperature of the catalyst reaches the activation temperature.  
     
     
         9 . A control system for an internal combustion engine incorporating cooling water for cooling the engine, a circulation passage for the cooling water, a water pump for controlling a flow rate of the cooling water and catalyst for purifying exhaust gas from the engine, characterized in that 
 if a temperature of the catalyst is not greater than an activation temperature, control is made in such a way that at least either (1) an ignition timing is retarded from the normal one, (2) the water pump is stopped, or (3) the flow rate of the cooling water becomes less than the normal one,    if the temperature of the catalyst is higher than the activation temperature, control is made in such a way that at least either (5) the water pump is controlled in accordance with a temperature of the cooling water, or (6) the ignition timing is advanced from the normal one, until the temperature of the cooling water reaches a warm-up temperature which is a normal operation temperature of the engine.    
     
     
         10 . A control system for an internal combustion engine as set forth in  claim 9 , further comprising a knocking sensor for detecting knocking of the internal combustion engine, wherein when knocking is detected, the ignition timing is retarded under control, and the water pump is controlled so as to increase the flow rate of the cooling water.  
     
     
         11 . A control system for an internal combustion engine incorporating a turbocharger for supercharging intake air in the engine, a cooling passage for cooling the turbocharger and catalyst for purifying exhaust gas, characterized by a valve for controlling a flow rate of cooling water flowing through the cooling passage, wherein the valve is controlled so as to decrease the flow rate of the cooling water flowing through the cooling passage if the temperature of the catalyst is not greater than an activation temperature.  
     
     
         12 . A control system for an internal combustion engine incorporating a transmission for transmitting a power from the engine, an oil cooler for cooling oil which lubricates the transmission, a cooling passage for cooling the oil cooler, and catalyst for purifying exhaust gas, characterized by a shut-off valve for blocking the cooling passage, wherein the shut-off valve is controlled so as to stop the flow of the cooling water in the cooling passage if a temperature of the catalyst is not greater than an activation temperature.