MotoTune:FAQ:Using Batch Fuel Injection vs. Sequential or Standard Fuel Injection Mode

By definition batch fuel injection references a crankshaft position sensor only. It can identify the crankshaft position, but it cannot identify the camshaft phase.

Because of this, all of the injectors fire each revolution. Two injectors from complementing cylinders will fire simultaneously. Complementing cylinders are defined as cylinders which fire at the same crankshaft position, but at opposite cam phases. Injector firing will be evenly distributed across the engine revolution.

In batch injection there will be half as many driver outputs as there are cylinders (assuming an engine with an even cylinder count).

The hardware requirements to run batch injection are to drive two injectors on each injector driver. For maximum efficiency, each injector pair must be from complementing cylinders.

In a V6 example that has a firing order of: 1-6-5-4-3-2, cylinders 1-4, 6-3, and 5-2 are complementing cylinders. FI1D pin will connect to injector 1 and 4. FI2D pin will connect to injector 2 and 5. FI3D pin will connect to injector 3 and 6. Each FI pin will connect to the same cylinder number, and it’s complement.

The hardware requirements in standard mode require one driver for each cylinder, as each injector will fire individually over one engine cycle. In that case, each FI pin will connect to the same cylinder number.

The software differences are subtle. In each case the correct firing order is needed in the encoder block, or encoder calibration in Mototune. The firing order is the same in either case.

However, there is an ‘injector behavior’ switch. It may be set to be calibrateable in Mototune, or set as a software change only. Changing this between ‘Standard’, and ‘Batch’ will alter the injector driver function between the two modes.

Use caution when making changes to injector mode types, as incorrect software OR hardware implementation can cause engine damage.

Note the above only applies to fuel injection control. Ignition Control must be implemented separately.

Additional Info

Examples of different Fuel Injection Sequences: Fuel Injector Sequence