TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Components: The oxidant comprises air, oxygen-enriched air, essentially pure oxygen, or a gas mixture comprising oxygen and nitrogen as main components, and/or the hydrocarbon fuel is selected from gasoline, light oil (diesel fuel), biodiesel fuel, natural gas, ethane, propane, and alcohols. The catalyst comprises an ultra-short-channel-length metal mesh substrate having one or more noble metals deposited to it, where preferably the hydrocarbon fuel is diesel fuel and the oxidant is air. Preferred Composition: In process steps (a) and (b), an equivalence ratio of hydrocarbon fuel to oxidant fed to the reactor is greater than 1:1. Preferred Process: In catalytic partial oxidation with in-situ coke removal, the hydrocarbon fuel is fed to the reactor in a pulsed on-off cycle, where the pulsed on-off cycle preferably ranges from about 5 milliseconds to about 50 milliseconds. Step (c) is conducted at a temperature greater than 600 degrees C and less than 1100 degrees C. In step (d),either the feed of hydrocarbon fuel is decreased or stopped while the oxidant feed is maintained to produce a fuel-lean feed ratio of fuel to oxidant to the reactor or the oxidant feed is increased while the feed of hydrocarbon fuel is maintained to produce a fuel-lean feed ratio of fuel to oxidant to the reactor. The hydrocarbon fuel and oxidant are fed to the reactor in an equivalence ratio less than 1:1. All process steps (a) through (f) are conducted in the absence of co-fed water or steam. Hydrocarbon fuel and oxidant are fed into a reactor and contacted with a catalyst under catalytic partial oxidation conditions sufficient to produce at least one partially-oxidized reaction product; the improvement comprises: (i) varying the feed of hydrocarbon fuel, or the feed of oxidant, or both feeds to produce a fuel-rich feed ratio of hydrocarbon fuel to oxidant to the reactor; and maintaining the fuel-rich feed ratio for a fuel-rich cycle-time sufficient to produce at least one partially-oxidized reaction product; (ii) varying the feed of hydrocarbon fuel, or the feed of oxidant, or both feeds to produce a fuel-lean feed ratio of hydrocarbon fuel to oxidant to the reactor; and maintaining the fuel-lean feed ratio for a fuel-lean cycle-time sufficient to remove coke deposits and to maintain a substantially constant yield of partially-oxidized reaction product; and (iii) reiterating process steps (i) to (ii) throughout the process. Preferred Parameters: A duty ratio, which is the total time that the hydrocarbon fuel is fed to the reactor during the pulsed on-off cycle, ranges from 20 percent to 80 percent of the pulsed on-off cycle. Fuel-rich cycle-time is greater than 20 seconds but less than a time that would raise the process temperature to greater than 1050 degrees C when the fuel is shut off. The fuel-lean cycle-time is greater than 5 milliseconds and shorter than a time that would result in a decrease of more than 10 percent in the percentage difference between maximum and minimum yields of partially-oxidized reaction product. Fuel-lean cycle-time is greater than 100 milliseconds and less than 1000 milliseconds. A substantially constant yield refers to a percentage difference between maximum and minimum yields of partially-oxidized reaction product of less than 10 percent over the first 60 minutes of process operation.