Open-valve Port Fuel Injection Of Alcohol In Multiple Injector Engines

Abstract

An engine having two or more fuel injectors is disclosed, where at least one of the injectors is used to port fuel inject fuel into the cylinder when the air intake valve is open. The open valve port fuel injector is used to inject a fuel that has alcohol as a constituent and is the same fuel injected by another fuel injector. In other embodiments, the open valve fuel injector is used to inject an anti-knock fuel containing alcohol while a primary fuel, is introduced by another injector. The operation of the open valve fuel injector can be optimized to maximize the vaporization cooling. In other embodiments, the open valve fuel injector may be used in conjunction with direct injection of the primary fuel or the anti-knock fuel. Heavy EGR can be optimally used with the various embodiments.

What is claimed is: 
     
         1 . A spark ignition engine, having at least one cylinder and an intake valve, where a fuel that contains alcohol as a constituent is introduced into the cylinder by a first port fuel injector and the same fuel is also introduced into the cylinder by a second port fuel injector, where the fuel from the second port fuel injector is introduced in such a way that it vaporizes inside the cylinder and the vaporization cools the fuel-air mixture in the cylinder;
 wherein, for a given amount of fuel injected by a fuel injector, fuel injected by the second port fuel injector provides more vaporization cooling than fuel provided by the first port fuel injector;   and wherein the ratio of the amount of fuel from the second port fuel injector to the amount of fuel from the first port fuel injector increases with increasing torque.   
     
     
         2 . The spark ignition engine of  claim 1 , where the ratio of the amount of fuel from the second port fuel to the amount of fuel from the first port fuel injector is determined by the requirement of avoiding knock. 
     
     
         3 . The spark ignition engine of  claim 1 , where hot EGR is used at low loads and the EGR is reduced or eliminated at high loads. 
     
     
         4 . The spark ignition engine of  claim 1 , where at least 30% EGR is used. 
     
     
         5 . The spark ignition engine of  claim 1 , where the EGR level is decreased when the alcohol content in the fuel is decreased. 
     
     
         6 . The spark ignition engine of  claim 1 , where the compression ratio is at least 14. 
     
     
         7 . A spark ignition engine, having at least one cylinder and an intake valve, where a first fuel is introduced by a first fuel injector and where a second fuel of which alcohol is a constituent having a higher alcohol concentration than the first fuel and which has a different composition than the first fuel, is introduced by a second fuel injector, which is a port fuel injector, where the second fuel from the second fuel injector is introduced in such a way that it vaporizes inside the cylinder and the vaporization cools the fuel-air mixture in the cylinder;
 wherein the second fuel from the second fuel injector is introduced while the intake valve is open;   wherein the second fuel injected by the second fuel injector provides more vaporization cooling than the first fuel provided by the first fuel injector; and   wherein the ratio of the amount of second fuel introduced from the second fuel injector to the amount of first fuel introduced from the first fuel injector increases with increasing torque.   
     
     
         8 . The spark ignition engine of  claim 7 , where the ratio of the amount of second fuel from the second port fuel injector to the amount of first fuel from the first port fuel injector is determined by the requirement of avoiding knock. 
     
     
         9 . The spark ignition engine of  claim 7 , where hot EGR is used at low loads and the EGR is reduced or eliminated at high loads. 
     
     
         10 . The spark ignition engine of  claim 7 , where at least 30% EGR is used. 
     
     
         11 . The spark ignition engine of  claim 7 , where the compression ratio is at least 14. 
     
     
         12 . The spark ignition engine of  claim 7 , wherein the second port fuel injector is located closer to the intake valve than the first port fuel injector. 
     
     
         13 . The spark ignition engine of  claim 7 , wherein the second port fuel injector produces smaller droplets than the first port fuel injector. 
     
     
         14 . The spark ignition engine of  claim 7 , wherein the first fuel injector introduces natural gas or another gaseous fuel into the engine. 
     
     
         15 . A spark ignition engine, having at least one cylinder and an intake valve, where a first fuel is introduced by a first fuel injector which is a closed valve port fuel injector and where a second fuel, which has methanol as a constituent, is introduced by a second fuel injector which is an open-valve port fuel injector;
 and where the second fuel is produced by onboard separation from a methanol-gasoline mixture,   and where the ratio of the amount of second fuel introduced into the engine from the second fuel injector to the amount of first fuel introduced into the engine by the first fuel injector increases with increasing torque.   
     
     
         16 . The spark ignition engine of  claim 15 , where the second fuel injector is located closer to the intake valve than the first fuel injector. 
     
     
         17 . The spark ignition engine of  claim 15 , where the second fuel injector introduces smaller droplets into the engine than the first fuel injector. 
     
     
         18 . The spark ignition engine of  claim 15 , where hot EGR is used at low loads and EGR is reduced or eliminated at high loads. 
     
     
         19 . The spark ignition engine of  claim 15 , where the methanol-gasoline mixture is M15. 
     
     
         20 . The spark ignition engine of  claim 15 , where the amount of methanol in the methanol-gasoline mixture varies, and where EGR is used and the EGR level decreases when the amount of methanol in the methanol-gasoline mixture decreases. 
     
     
         21 . The spark ignition engine of  claim 15 , where the amount of second fuel that is used in the engine is determined by the requirement to prevent knock. 
     
     
         22 . A spark ignition engine where a first fuel is introduced into the engine by a first fuel injector and by a second fuel injector, where the first and second fuel injectors are port fuel injectors, and the second port fuel injector provides more vaporization cooling than the first port fuel injector and the ratio of the amount of fuel provided by the second fuel injector to the amount provided by the first fuel injector increases with increasing torque;
 wherein a second fuel is introduced by third fuel injector, wherein the third fuel injector is a direct injector;   wherein the ratio of the amount of the second fuel to the amount of first fuel that is used in the engine increases with increasing torque;   and wherein the engine is operated with a substantially stoichiometric fuel-air ratio.   
     
     
         23 . A spark ignition engine in a vehicle comprising a tank in which methanol-gasoline mixtures of varying methanol content are stored; and where a first fuel injector introduces a first fuel and a second fuel injector introduces a second fuel where the second fuel is produced from onboard separation from the stored methanol-gasoline mixture and has a higher methanol content than both the first fuel and the methanol-gasoline mixture from which it is produced;
 where the ratio of the second fuel to the first fuel increases with increasing torque so as to prevent knock;   and where the operation of the onboard separation system is varied as a function of the amount of methanol in the methanol-gasoline mixture.   
     
     
         24 . The spark ignition engine of  claim 23 , where the second fuel injector introduces a higher fraction of fuel as a liquid into a least one cylinder in comparison to the first fuel injector. 
     
     
         25 . The spark ignition engine of  claim 23 , where the first fuel injector is a closed valve port fuel injector. 
     
     
         26 . The spark ignition engine of  claim 23 , where the second fuel injector is an open-valve port fuel injector. 
     
     
         27 . The spark ignition engine of  claim 23 , where the methanol-gasoline mixture is M15. 
     
     
         28 . The spark ignition engine of  claim 23 , where, when the methanol in the methanol-gasoline mixture in the tank is reduced, the effective compression ratio is reduced.