Fuel composition containing iron and manganese to reduce spark plug fouling

1. A method of forming reduced conductivity deposits on spark plugs, said method comprising:

combusting a fuel comprising ferrocene and a manganese-containing compound in an apparatus comprising the spark plugs, the treat rate of the manganese-containing compound ranging from about 1 to about 20 mg of manganese per liter of fuel, the weight ratio of iron metal to manganese metal in the fuel ranging from about 2:36 to 35:36,

wherein the apparatus is chosen from spray guided-, wall guided-, and combined wall/spray guided-direct injection gasoline (DIG) engines; turbocharged DIG engines; supercharged DIG engines; homogeneous combustion DIG engines; homogeneous/stratified DIG engines; DIG engines outfitted with piezo injectors capable of multiple fuel pulses per injection; DIG engines with EGR; DIG engines with a lean NOx trap; DIG engines with a lean-NOx catalyst; DIG engines with SN-CR NOx control; DIG engines with exhaust diesel fuel after-injection for NOx control; DIG engines outfitted for flex fuel operation; advanced port-fueled gasoline engines; gasoline-fueled homogeneous charge compression ignition (HCCI) engines; gasoline HCCI-electric hybrid engines; and gasoline-electric hybrid vehicles,

wherein the manganese-containing compound is methylcyclopentadienyl manganese tricarbonyl.

2. The method of claim 1 , wherein the fuel comprises ferrocene in an amount of from about 1 to about 35 mg of iron per liter of fuel.

3. The method claim 1 , wherein the conductivity of the deposit composition is about an order of magnitude less than the conductivity of a deposit composition that would be formed using the same fuel without the manganese containing compound in the same engine combusting process.

4. The method of claim 1 , wherein the weight ratio of iron metal to manganese metal in the fuel ranges from 3:4 to less than 1:1.

5. A deposit composition produced by combusting a fuel comprising:

(a) ferrocene and

(b) methylcyclopentadienyl manganese tricarbonyl at a treat rate ranging from about 1 to about 20 mg of manganese per liter of fuel,

wherein the deposit composition has a conductivity of about an order of magnitude less than the conductivity of a deposit composition that would be formed using the same fuel in the same engine combusting process without the manganese containing compound, and

wherein the weight ratio of iron metal to manganese metal in the fuel ranges from about 2:36 to 35:36.

6. The deposit composition of claim 5 , wherein the fuel comprises ferrocene in an amount of from about 1 to about 35 mg of iron per liter of fuel.

7. The composition of claim 5 , wherein the weight ratio of iron metal to manganese metal in the fuel ranges from 3:4 to less than 1:1.

8. A fuel system comprising

(a) a fuel,

(b) ferrocene, in an amount of from about 1 to about 35 mg of iron per liter of fuel,

(c) methylcyclopentadienyl manganese tricarbonyl at a treat rate ranging from about 1 to about 20 mg of manganese per liter of fuel, and

(d) a combustion system combusting said fuel,

wherein the fuel system produces a spark plug deposit composition, the conductivity of the deposit composition being less than the conductivity of a deposit composition that would be formed using the same fuel without the manganese containing compound in the same engine combusting process, and

wherein the spark plugs are present in an apparatus chosen from spray guided, wall guided, and combined wall/spray guided-direct injection gasoline (DIG) engines; turbocharged DIG engines; supercharged DIG engines; homogeneous combustion DIG engines; homogeneous/stratified DIG engines; DIG engines outfitted with piezoinjectors capable of multiple fuel pulses per injection; DIG engines with EGR; DIG engines with a lean NOx trap; DIG engines with a lean-NOx catalyst; DIG engines with SN-CR NOx control; DIG engines with exhaust diesel fuel after-injection for NOx control; DIG engines outfitted for flex fuel operation; advanced port-fueled gasoline engines; gasoline-fueled homogeneous charge compression ignition (HCCI) engines; gasoline HCCI-electric hybrid engines; and gasoline-electric hybrid vehicles, and

wherein the weight ratio of iron metal to manganese metal in the fuel ranges from about 2:36 to 35:36.

9. The fuel system of claim 8 , wherein said combustion system is spark ignited or compression ignited.

10. The fuel system of claim 8 , wherein said combustion system has a glow plug ignition.

11. The method claim 8 , wherein the conductivity of the deposit composition is about an order of magnitude less than the conductivity of a deposit composition that would be formed using the same fuel without the manganese containing compound in the same engine combusting process.

12. The system of claim 8 , wherein the weight ratio of iron metal to manganese metal in the fuel ranges from 3:4 to less than 1:1.

13. A method of reducing spark plug misfire in an apparatus comprising spark plugs, said method comprising:

combusting a fuel comprising ferrocene and a manganese-containing compound in the apparatus, the fuel including the manganese-containing compound at a treat rate ranging from about 1 to about 20 mg of manganese per liter of fuel, the weight ratio of iron metal to manganese metal in the fuel ranging from about 2:36 to 35:36,

wherein the apparatus is chosen from spray guided-, wall guided-, and combined wall/spray guided-direct injection gasoline (DIG) engines; turbocharged DIG engines; supercharged DIG engines; homogeneous combustion DIG engines; homogeneous/stratified DIG engines; DIG engines outfitted with piezoinjectors capable of multiple fuel pulses per injection; DIG engines with EGR; DIG engines with a lean NOx trap; DIG engines with a lean-NOx catalyst; DIG engines with SN-CR NOx control;

DIG engines with exhaust diesel fuel after-injection for NOx control; DIG engines outfitted for flex fuel operation; advanced port-fueled gasoline engines; gasoline-fueled homogeneous charge compression ignition (HCCI) engines; gasoline HCCI-electric hybrid engines; and gasoline-electric hybrid vehicles, wherein the spark plug misfire is reduced relative to spark plug misfire that would occur in the same method except for using a fuel without a manganese-containing compound, and

wherein the manganese-containing compound is methylcyclopentadienyl manganese tricarbonyl.

14. The method of claim 13 , wherein the fuel comprises ferrocene in an amount of from about 1 to about 35 mg of iron per liter of fuel.

15. The method of claim 13 , wherein the weight ratio of iron metal to manganese metal in the fuel ranges from 3:4 to less than 1:1.

16. A method of preventing spark plug misfire in an engine combusting a fuel comprising ferrocene, said method comprising:

adding a manganese-containing compound to the fuel at a treat rate ranging from about 1 to about 20 mg of manganese/liter of fuel, the weight ratio of iron metal to manganese metal in the fuel ranging from about 2:36 to 35:36, wherein lack of spark plug misfire is identified by the absence of a malfunction indicator light (MIL) code on an on-board diagnostic system (OBD) connected to the engine,

wherein the manganese-containing compound is methylcyclopentadienyl manganese tricarbonyl.

17. The method of claim 16 , wherein the fuel comprises ferrocene in an amount of from about 1 to about 35 mg of iron per liter of fuel.