Abstract: Method and apparatus for controlling the food cooking time in a microprocessor controlled microwave oven in response to the remotely sensed condition of the food being heated. The average food temperature is constantly derived during cooking, utilizing user entered data on the food category, the food's initial mass, and the measured input power to the magnetron. The average current and average peak voltage input to the magnetron are sensed and the absorbed power in the food is derived using the magnetron efficiency. A self-calibrating analog to digital converter provides the magnetron input power in digital form for a microprocessor controller. In one embodiment the microprocessor sequentially derives the average food temperature as a function of cooking time using the entered food data, stored cooking coefficients previously determined by regression analysis, and the measured magnetron input power.

Abstract: A method of browning food in a microwave oven. The method comprises alternating over the entire cooking cycle the application of power to a microwave generating device with the application of power to an infrared heater. The operational periods of each type of radiation device are automatically varied over the cooking cycle. The parameters of these periods are empirically predetermined for each broad category of food and retained in a nonvolatile memory. In one embodiment, the periods are adjusted to compensate for varying quantities of food and desired donenesses by relating them to a total cooking time per unit mass empirically predetermined for each food category and doneness. Alternatively, the periods are adjusted by entering the food mass into a microprocessor in the oven. The microprocessor calculates the cooking time by use of the food category, food mass and power input to the microwave generating device.

Abstract: Method and apparatus for controlling the food cooking time in a microprocessor controlled microwave oven in response to the remotely sensed condition of the food being heated. The average food temperature is constantly derived during cooking, utilizing user entered data on the food category, the food's initial mass, and the measured input power to the magnetron. The average current and average peak voltage input to the magnetron are sensed and the absorbed power in the food is derived using the magnetron efficiency. A self-calibrating analog to digital converter provides the magnetron input power in digital form for a microprocessor controller. In one embodiment the microprocessor sequentially derives the average food temperature as a function of cooking time using the entered food data, stored cooking coefficients previously determined by regression analysis, and the measured magnetron input power.

Abstract: A method of cooking thin meat in a microwave oven by determining the temperature of the thin meat as a function of humidity and temperature environmental conditions of a microwave oven heating cavity. The relative humidity of the oven heating cavity is continuously sampled during cooking, and signals indicative of the humidity are provided to a digital computing device having a memory such as a programmable microprocessor. The slope of the curve of humidity as a function of elapsed time is compared to the slope of a characteristic curve for thin meats stored in the microprocessor. The doneness time is calculated from the comparison of the curves and cooking is terminated when the calculated doneness time is reached.

Abstract: A method for effectively browning foods in a microwave oven by controlling the humidity of the cooking environment. Humidity and temperature sensors are provided to measure the relative humidity of the environment surrounding a foodstuff to be browned as the food is cooked by microwave energy. The actual sensed conditions are compared with a predetermined optimum relative humidity. Adjustments to the relative humidity are then made by either increasing or decreasing the air exchange rate, or by increasing or decreasing the amount of heat added to the air exchanged, or both.

Abstract: A method of cooking meat in a microwave oven by determining the mean internal temperature of the meat which is indicative of the internal doneness of meat as a function of sensed and sampled time dependent humidity and temperature of the microwave oven heating cavity. The mean internal temperature of the meat is determined as a function of the initial temperature of the meat; a net heat loss due to surface evaporation; a net input of energy by the microwave power source, and a net convective heat loss.

Abstract: A method for indicating the optimum time at which to turn meat over in a microwave oven. The method detects the point where the absolute humidity remains constant and no longer increases indicating that the temperature of the meat has reached an equilibrium point. At the temperature equilibrium point, the meat is ready to be turned over.

Abstract: A microwave oven sensing system having a humidity sensor and a temperature sensor at an exit ventilation port of a microwave oven heating cavity to sense the exiting humidity and the air temperature of the microwave oven heating cavity. The humidity sensor and the temperature sensor are positioned to sense the "in-situ" environmental conditions of the microwave oven heating cavity such as adjacent to and by the exterior of the exit ventilation port of the microwave oven heating cavity. The sensors connect to a programmable controller and input the sensed "in-situ" environmental conditions of the microwave oven heating cavity to the programmable controller. "Characteristic humidity curves" for microwave cooking of different types of foods are stored as algorithms in a memory of the programmable controlled and the programmable controller controls the microwave cooking in accordance with a selected algorithm for the sensed "in-situ" environmental conditions.

Abstract: A method of cooking foods containing a substantial liquid component by sensing "in-situ" humidity and temperature environmental conditions of a microwave oven heating cavity. The method monitors the rate of change of the slope of the "characteristic humidity curve" to indicate the degree of cooking of the foods. By determining the rate of change of the slope of the "characteristic humidity curve", the value is indicative of the degree of the temperature level of microwave cooking of the foods and can be used to control microwave cooking of the foods.

Abstract: A method for detecting a fire in a microwave oven heating cavity by sensing the time dependent "in-situ" humidity and the temperature environmental conditions of a microwave oven heating cavity in a microwave oven. The humidity sensor and the temperature sensor connect to a programmable controller in the microwave oven. When the sensed "in-situ" relative humidity decreases and the sensed temperature increases within a predetermined time interval, there is a fire in the cavity. The programmable controller processing the sampled humidity and temperature signal information turns off the microwave oven upon sensing the decreasing humidity and increasing temperature within the predetermined time interval indicating a fire.