On closer inspection, however, one sees that the engine being used as the basis for the system is an in-line four (or six, or eight) with direct injection:
"the engine 3 is an in-line multi-cylinder gasoline engine having a multiplicity of pairs of cylinders 3a and pistons 3b (only one pair of which is shown) ... the engine 3 is configured as a direct injection engine. Further, the fuel injection valve 10 is electrically connected to the ECU 2 and the valve-opening time period and the valve-opening timing thereof are controlled by the ECU 2, whereby the fuel injection control is carried out, as will be described hereinafter."
Let's see if the engine in this patent application turns out to be based on an actual prototype Honda plans on bringing to market. Here's a picture from the patent application:
Honda's patent application can be found here.