Abstract: An oil pressure warning system for an outboard motor for detecting and alarming an abnormal oil pressure of an internal combustion a first oil pressure switch which generates an ON signal when the oil pressure is less than or equal to a first predetermined oil pressure, and a second oil pressure switch which generates an ON signal the oil pressure is less than or equal to a second predetermined oil pressure set higher than the first predetermined oil pressure. The abnormality of oil pressure is detected and alarmed based on the ON signal of the switches. The first and second predetermined oil pressures are first and second predetermined oil pressures is determined based on an oil pressure characteristic of a (possible) maximum oil temperature (under which the engine has been warmed up) set relative to the engine speed, thereby ensuring to detect and alarm the abnormality of oil pressure under any engine speed and any oil temperature.

Abstract: An oil proper amount informing apparatus for engines capable of simply checking whether or not a remaining amount or level of oil is proper even if the period of time of warming-up varies. An oil level gauge mounted to an oil reservoir unit, a temperature sensor for detecting the temperature of oil, and temperature indicating means for indicating the temperature on the basis of a detected signal of the temperature sensor are provided. The temperature indicating means indicates the temperature of oil in either of a plurality of divided regions H, M, and L, each of which has a predetermined width or range of temperature. The oil level gauge is provided with the indicating regions H, M, and L, each of which indicates an proper amount of oil at a position corresponding to the proper amount of oil in each of the temperature regions H, M, and L.

Abstract: A reliable capacitive oil deterioration and level sensor has a conductive housing member that includes a conductive shielding member defining a ground electrode, and a conductive inner member defining a measuring electrode. The shielding member protects the sensor from moving objects that could adversely affect its performance. The housing member is adapted to provide a fluidic connection between an oil container and a space between the ground electrode and the measuring electrode. The sensor also includes electronics adapted to employ this capacitor geometry to generate signals indicative of a degree of deterioration and a level of the oil within the gap. The electronics further include at least one isolating capacitor to eliminate a flow of current between the electrodes that may cause a build up of material on the two electrodes that define the capacitor. This build up of unwanted material may cause an undesirable effect in the sensor output signal.

Abstract: A limit-level sensor for measuring level of a liquid has a resistance element which has an electric resistance which suddenly varies a transition temperature which lies above the maximum liquid temperature. The resistance element is first heated by electric current. Thereupon, the electric resistance of the resistance element is measured. When the resistance element is covered with liquid, the heat generated by the electric current is led away so that the temperature of the resistance element is less than its transition temperature. If the resistance element is not covered by liquid, this heat is scarcely led away, so that the temperature of the resistance element remains above the transition temperature.

Abstract: The inexpensive sensor detects a low oil or no oil condition in an internal combustion engine and shuts down the engine. The sensor includes two inductors having different resistances disposed in a sensing bridge. The inductors are heated by a steady low voltage. A periodic higher voltage is applied to the inductors by means of a power winding disposed on the same frame as the ignition coil. When at least one of the inductors is disposed in air and not in oil, an imbalance is created in the sensing circuit that is used to short out the ignition primary. Alternatively, the sensor can be used to provide a visual or audible indication of a low oil level without stopping the engine.

Abstract: In a preferred embodiment, an engine oil change indicator system, including: a combination engine oil pressure sensor and engine oil temperature sensor connected to a port on the engine to which port is normally connected an oil pressure switch; and a microprocessor connected to receive inputs from the combination engine oil pressure sensor and engine oil temperature sensor and to cause a low engine oil pressure warning light to be illuminated when the microprocessor has calculated from the inputs that the engine oil should be changed.

Abstract: A voice warning system for automobiles includes a microprocessor connected with the battery of an automobile, a plurality of sensors arranged on different parts of the engine and connected with the microprocessor, and two voice integrated circuits for storing voice messages, whereby the microprocessor will give voice messages to notify the driver of the conditions of the car thereby ensuring the safety of the driver.

Abstract: A real-time maintenance alert system and method for use in a heavy-duty truck having an engine controller with memory are provided. The system includes a sensor operative to indicate an engine condition from the group consisting of: oil filter restriction, air filter restriction, fuel filter restriction, oil level, and coolant reserve tank fluid level. Control logic at the engine controller processes the sensor signal to determine a real-time fault condition, when appropriate.