Approach for reducing overheating of direct injection fuel injectors

A vehicle system, comprising:

• a first fuel storage tank;
• a second fuel storage tank separate from the first fuel storage tank;
• at least one cylinder;
• a port injection fuel injector to inject fuel into an intake passage in operative communication with the at least one cylinder, the port injection fuel injector being supplied with a first type of fuel from the first fuel storage tank;
• a direct injection fuel injector to inject fuel directly into the at least one cylinder, the direct injection fuel injector being selectively supplied with the first type of fuel from the first fuel storage tank and the second type of fuel from the second fuel storage tank;
• and
• a control system configured to cause the second type of fuel from the second storage tank to be supplied to the direct injection fuel injector in response to an amount of the second type of fuel in the second fuel storage tank exceeding a threshold amount, and configured to cause the first type of fuel from the first storage tank to be supplied to the direct injection fuel injector in response to the amount of the second type of fuel in the second fuel storage tank not exceeding the threshold amount.