Wisconsin Alumni Research Foundation

Gm Global Technolgoy Operations, Inc.

David Darin Wickman

Sage Lucas Kokjohn

Carl-Anders Hergart

Ramachandra Diwakar

Shengming Chang

Flavio Dal Forno Chuahy

A compression ignition engine system allows use of hydrous fuels, in particular hydrous biofuels, with high water content (e.g., 20-85% water). The hydrous fuel is pressurized, and also preferably heated via the engine's exhaust gas, to increase its enthalpy, and is then directly injected into the engine cylinder(s) near top dead center. The system provides brake thermal efficiency increases of 20% or more versus a comparable system using conventional diesel fuel, while allowing the use of inexpensive undistilled or lightly distilled biofuels.

Wet biofuel compression ignition

An engine/reformer system accepts a first fuel and reforms it into syngas for use as a fuel in an accompanying internal combustion engine. Prior to reforming, the first fuel is pressurized and/or heated to at or near supercritical fluid conditions, such that the resulting syngas leaves the reformer in a supercritical fluid state. Injection of the supercritical syngas into an engine cylinder avoids the autoignition problems that occur when gaseous syngas is used. The first fuel is a fully self-reforming fuel (one that needs no separate water supply for complete conversion to syngas), and can beneficially be a 'wet' fuel, such as ethanol containing water, allowing the system to use intermediate products of an ethanol production process (such as hydrous ethanol and stillage wastewater) as fuel, and reducing the overall cost of fuel production and engine operation.

Supercritical reforming of fuels, without separate water supply, for internal combustion engines

A first engine fuel, for example diesel fuel, is reformed (preferably via steam reforming) to produce syngas for use as a second engine fuel, with the fuels then both being used in an internal combustion engine to perform Reactivity Controlled Compression Ignition (RCCI). The syngas is produced and supplied to the engine as a supercritical fluid, thereby avoiding the pumping losses that would occur if syngas was pressurized for supply/injection. The reforming is done by a reformer which is provided as a unit with the engine (e.g., both the engine and reformer are onboard a vehicle), thereby effectively allowing use of a single fuel for RCCI engine operation.

Engines using supercritical syngas

A piston for a diesel engine has a crown and a three-dimensional shape defined in an x-y-z coordinate space. The z-axis generally defines a cylinder axis of the piston, and the plane z=0 generally intersects an upper rim of the crown. The piston includes a combustion bowl recessed in the crown. The combustion bowl has a center point on the z-axis and has a two-dimensional partial cross-sectional configuration defined by a peripheral line connecting coordinate points (x,y,z) in the x-y-z coordinate space. The (x,y,z) coordinate points include points from a coordinate set S. The combustion bowl has a three-dimensional axisymmetric configuration defined by rotating the peripheral line 360&#xb0; about the z-axis.

Low emissions diesel piston

The present invention is a compression ignition internal combustion engine and method of operation which expands the load limit of quietly operating a premixed charge compression ignition (PCCI) engine by injecting a secondary fuel B, in ratios lean of stoichiometric, either into the intake air stream or directly into the cylinder to form a homogeneous fuel B and air mixture. Near top dead center of the compression stroke, a PCCI-type direct injection of fuel A event is used to initiate combustion of both fuel A and B at the proper time. At low loads the combustion mode is characterized a PCCI-type with high EGR rates. At medium loads the combustion mode is that of homogeneous combustion of fuel B coupled with PCCI combustion of fuel A. At the highest loads the engine will revert to a conventional diesel combustion mode of fuel A to maintain power density.

Growing community of inventors

Madison, WI, United States of America

David Darin Wickman