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.

Description

[0001]This application claims priority of U.S. Provisional Patent Application Ser. Nos. 61 / 535,404, filed Sep. 16, 2011; 61 / 603,977 filed on Feb. 28, 2012; 61 / 663,670, filed Jun. 25, 2012; and 61 / 667,493 filed Jul. 3, 2012, the disclosures of which are incorporated herein by reference in their entireties.BACKGROUND OF THE INVENTION[0002]The performance and efficiency of spark ignition engines can be increased by increasing knock resistance. Direct injection of alcohol in spark ignition gasoline engines provides strong vaporization cooling of the fuel-air mixture in the cylinders and thereby substantially increases knock resistance. The increased knock resistance allows operation and higher compression ratio and / or higher levels of turbocharging.[0003]The alcohol can be either directly injected from a single source by itself or along with gasoline or another fuel, or injected on-demand from a secondary tank into an engine that is primarily fueled with gasoline. For example, U.S. Pat....

AI Technical Summary

Benefits of technology

[0009]An engine having two of more fuel injectors is disclosed, where at least one of the fuel injectors is used to port fuel inject fuel into the cylinder when the air intake valve is open. This provides vaporization cooling, thereby increasing the stability of the gaseous mixture and reducing autoignition. In some embodiments, the open valve fuel injector is used to inject the primary fuel, which is typically gasoline. In other embodiments, the open valve fuel injector is used for separately controlled injection of an anti-knock fuel that contains alcohol. The position and operation of the open valve fuel injector can also be modified to optimize the vaporization cooling provided by the fuel injected through this injector. In other embodiments, the open valve fuel injector may be used in connection with direct injection of either the primary fuel or the anti-knock fuel.

Problems solved by technology

Direct injection, however, has the disadvantage that if it is to be employed by modifying existing engines that are not direct injection spark ignition engines, it is necessary to change the engine head in order to provide the additional penetration for the direct injector.

This can substantially increase the effort that is required for engine modification.

However, as discussed in this patent, it has the disadvantage that, while there is a knock resistance improvement from the higher chemical octane of the alcohol relative to gasoline, the vaporization cooling effect inside the cylinder is lost in conventional port fuel injection.

However, it does not discuss a set of approaches that could be particularly effective in increasing the knock resistance of open-valve port fuel injection and minimizing the adverse effects of open valve port fuel injection.

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