Abstract: A controller for a vehicle is configured to execute a lubricating oil degradation degree acquisition process that calculates a degradation degree of a lubricating oil that lubricates an internal combustion engine, a battery degradation degree acquisition process that calculates a degradation degree of a battery, and an oil change time calculation process that calculates an oil change time for the lubricating oil from the degradation degree of the lubricating oil and the degradation degree of the battery. The oil change time calculation process includes calculating the oil change time so as to become earlier as the degradation degree of the battery increases.

Abstract: A method for providing the engine oil usage information may include determining, by a controller, a current engine driving state out of a plurality of predetermined driving states of an engine of the hybrid electric vehicle from driving information, determining, by the controller, a real-time cumulative distance value corresponding to the determined current engine driving state, updating, by the controller, an oil usage distance using the real-time cumulative distance value, determining, by the controller, an engine oil change time by comparing the updated oil usage distance with a predetermined engine oil change distance, and informing, by the controller, information related to the determined engine oil change time through a notification unit.

Abstract: A locomotive system is provided that includes a platform, plural wheel-axle sets operably coupled to the platform, a reservoir attached to the platform and configured to hold a fluid, and a resonant sensor probe assembly coupled to the reservoir. The sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid, to generate an electric field between the free-standing electrodes, and to measure an impedance response of the sensor to the fluid between the electrodes.

Abstract: Systems and methods are described for predicting a remaining oil life in an engine of a vehicle. One or more parameters of the engine can be monitored over a period of time. A hot compartment temperature can be determined from the parameter. A condition of the oil can be determined based on the hot compartment temperature, and the condition of the oil can be displayed.

Abstract: A fluid condition monitoring device includes a sensing assembly including a sensor and a transducer, the sensor to sense a property of the fluid and the transducer to apply a test signal to the fluid and receive a return signal from the fluid; a control assembly coupled to the sensing assembly, the control assembly including a controller and an input/output interface, the controller interfacing with the transducer to generate fluid condition information in response to the return signal; and an interface assembly coupled to the control assembly, the interface assembly including a connection to the input/output interface to transmit the fluid condition information to an external system.

Abstract: There is described herein methods and systems for comparing an engine fluid signature of a first engine with engine fluid signatures of other engines of a same engine family. A delta signature is obtained via the comparison and delta signatures below a given threshold are considered similar. Historical data for each engine having a similar signature may then be used to determine the condition and the future states of the first engine.

Abstract: Herein provided are methods and systems for detecting blockage of an inlet of gas turbine engine. An oil temperature measurement of the engine and an ambient temperature measurement is obtained. The oil temperature measurement is compared to a threshold based on the ambient temperature measurement. Blockage of the inlet of the engine is detected when the oil temperature measurement exceeds the threshold.

Abstract: A system includes a sensor that may measure one or more engine oil parameters to assess engine oil health of an engine and a processor communicatively coupled to the sensor and that may receive a signal from the sensor. The signal is representative of a real-time measurement of the one or more engine oil parameters. The processor may also estimate the one or more engine oil parameters over time via an adaptive predictive model associated with the one or more engine oil parameters to generate estimated data and reconcile the real-time measurement and the estimated data to generate an integrated engine oil degradation model and predict engine oil remaining useful life based on the integrated engine oil degradation model and one or more condemn limits associated with the one or more engine oil parameters.

Abstract: A device for determining a filling level of a container is provided, having a damping cup, a measuring section extending vertically inside the damping cup, and having an ultrasound converter arranged at its lower end region, and at least one antechamber. A calming structure is arranged in at least a part of at least one antechamber, to achieve as much degassing of the liquid as possible. The part of the antechamber having the calming structure is designed to be open towards the top over a large area and is connected, via a venting channel, with a vent in the upper region of the device.

Abstract: A sensing apparatus for detecting fluid quality change using signals obtained from a fluid quality sensor for exposure to a fluid and a reference sensor positioned in a reference sensing means having a fluid trap section holding a part of the fluid. Sensing values obtained from the fluid quality sensor and the reference sensor are compared in determining an aging factor. An application of the sensing apparatus is an apparatus for detecting engine oil quality change in an engine system. With the sensing apparatus, a first aging factor can be calculated after an engine cold soak and a second one can be obtained during engine operation. With these two aging factors, in addition to oil quality change, failures in the engine system and sensors, and oil change events can also be detected. Additionally, since reference sensing values are provided by the reference sensor, power disconnections have least effects.

Abstract: Embodiments provide systems and methods for using a feedback correction factor to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system. If the feedback correction factor is within a predetermined range, the vehicle is placed in a judging mode. If the feedback correction factor is outside a predetermined range, the vehicle is placed in a non-judging mode. Methods and systems for using an engine oil temperature to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system are disclosed. If an engine oil temperature, or predicted engine oil temperature, is below a predetermined temperature, the motor vehicle is placed in a non-judging mode. If an engine oil temperature, or predicted engine oil temperature, is above a predetermined temperature, the motor vehicle is placed in a judging mode.

Abstract: Systems and methods for monitoring engine oil temperatures to detect higher than normal oil temperatures are provided. The system comprises a plurality of sensors for obtaining input signals from the operating engine for a predetermined set of engine conditions. At least one of the plurality of sensors includes an oil temperature sensor for measuring an engine oil temperature. The system also includes an engine control unit (ECU) where a plurality of predetermined limit values corresponding to at least one predetermined set of engine operating conditions is stored. The engine control unit is configured to select a predetermined limit value corresponding to a measured set of engine operating conditions, to calculate a maintenance limit value using the selected predetermined limit value, and to compare the measured oil temperature with the maintenance limit value. An output unit outputs a predetermined output depending on the result of the comparison.

Abstract: A cetane number estimation apparatus injects fuel from a fuel injection valve in a diesel engine based on a target fuel injection amount, calculates an indicator of output torque of the diesel engine produced through fuel injection, and estimates the cetane number of the fuel using the calculated indicator. The cetane number estimation apparatus includes a pressure sensor for detecting fuel pressure varied by variation in actual fuel pressure in the fuel injection valve at the time of the fuel injection. The cetane number estimation apparatus also has a pressure correcting section that is adapted to calculate actual operating characteristics of the fuel injection valve based on a variation waveform of the detected fuel pressure and corrects the target fuel injection amount based on the difference between the calculated actual operating characteristics and prescribed reference operating characteristics.

Abstract: An oil filter and oil-additive dispensing device comprising an oil filter and oil additive replenishment system further comprising: a full-flow oil filter; a by-pass oil filter; an oil additive dispensing system; and an on-vehicle controller to dispense additive as required, track additive consumption and signal the need for a replacement system is described. Also a method of using such oil filter and oil-additive dispensing device to extend the useful life of lubricating oil in a vehicle engine is described.

Abstract: This invention encompasses embodiments for multi-modal integrated simultaneous measurement of various aspects of fluids contained in circulating systems such as automotive reciprocating engines and vehicle transmissions. These circulating systems perform constant internal lubrication, and heat and contaminant removal to protect the internal moving parts from the inherent friction and damage in normal operation. Most commonly this is achieved with fluids based on hydrocarbon and/or related synthetics, which, over time, can lose their protective properties, and vary in their performance or breakdown/decay due to internal and external events. Several components within the lubricant fluid can be measured and can provide insight into the efficacy of the system to perform its designed mission. Described herein is a real-time, simultaneous, integrated, multi-modal sensor system for early warning notification.

Abstract: This invention encompasses embodiments for multi-modal integrated simultaneous measurement of various aspects of fluids contained in circulating systems such as automotive reciprocating engines and vehicle transmissions. These circulating systems perform constant internal lubrication, and heat and contaminant removal to protect the internal moving parts from the inherent friction and damage in normal operation. Most commonly this is achieved with fluids based on hydrocarbon and/or related synthetics, which, over time, can lose their protective properties, and vary in their performance or breakdown/decay due to internal and external events. Several components within the lubricant fluid can be measured and can provide insight into the efficacy of the system to perform its designed mission. The mass and level of the fluid may also be monitored on an on-going basis. Described herein is a real-time, simultaneous, integrated, multi-modal sensor system for early warning notification.

Abstract: A method of monitoring oil in a vehicle having an internal combustion engine is provided. The method includes setting an original oil life, which is measured by event units occurring in the engine, and measuring a lapse of the event units. The method calculates a remaining oil life as a function of the lapse of event units and the original oil life. The remaining oil life is expressed in terms of the event units. The method monitors for oil additions and calculates an addition credit from any monitored oil additions. The method also includes calculating a modified oil life as a function of the addition credit, wherein the modified oil life is expressed in terms of the event units.

Abstract: A monitoring method that includes calculating the autonomy of a lubrication system of an airplane engine and also providing for the diagnosis and prognosis of a plurality of problems and breakdowns of the engine and of its lubrication system by means of measurements taken by sensors arranged in the lubrication system. The method further comprises the step of calculating the status of the lubrication system at a given moment and calculating its evolution over time in order to determine the remaining lifetime before a breakdown.

Abstract: Systems and methods for monitoring engine oil temperatures to detect higher than normal oil temperatures are provided. The system comprises a plurality of sensors for obtaining input signals from the operating engine for a predetermined set of engine conditions. At least one of the plurality of sensors includes an oil temperature sensor for measuring an engine oil temperature. The system also includes an engine control unit (ECU) where a plurality of predetermined limit values corresponding to at least one predetermined set of engine operating conditions is stored. The engine control unit is configured to select a predetermined limit value corresponding to a measured set of engine operating conditions, to calculate a maintenance limit value using the selected predetermined limit value, and to compare the measured oil temperature with the maintenance limit value. An output unit outputs a predetermined output depending on the result of the comparison.

Abstract: Disclosed in certain embodiments is a method of determining the individual concentration of different antioxidants of the same class in a sample comprising contacting the sample with an effective amount of phenol; and analyzing the sample by voltammetry.

Abstract: Systems and methods for testing an engine lubricant are provided. The system includes a tilting platform selectively movable between tilt angles and at least one test tray. The tilting platform includes a heated block with a heat source. The test tray has the engine lubricant therein. The test tray also has a heated portion and an unheated portion. The test tray is tiltably positionable on the tilting platform with the heated portion heatable by the heated block whereby the engine lubricant is selectively positionable about the heated and unheated portions of the test tray.

Abstract: A valve freeze control apparatus for an internal combustion engine includes a concentration sensor, a valve, a freeze control device, and a start determination unit. The concentration sensor is adapted to detect an alcohol concentration of fuel supplied to the internal combustion engine. The valve is provided in one of an intake passage and an exhaust passage of the internal combustion engine, wherein the valve controls flow of air that passes through the one of the intake and exhaust passages. The freeze control device is adapted to limit malfunction of the valve caused by freeze of water in exhaust gas, and the water has been attached to the valve. The start determination unit determines to start the freeze control device when the alcohol concentration detected by the concentration sensor is equal to or greater than a reference value.

Abstract: Internal combustion engines which are operated using ethanol exhibit an improved capability for lean-burn running. The lean-burn running limit with a higher ethanol proportion is displaced in the direction of lean. This link between the lean-burn running limit and the ethanol proportion of the fuel is used to determine the ethanol proportion. To determine the lean-burn running limit, a fuel quantity is injected into a cylinder in the operating range of the overrun fuel cut-off, with which fuel quantity no combustion of the air/fuel mixture occurs, and the fuel quantity is increased continuously until combustion occurs; the smooth running of the engine is monitored for this cylinder and the lean-burn running limit is detected as reached if the smooth running exceeds a predefined threshold value. The ethanol proportion is then deduced from the increase in the injected fuel quantity which is required to reach the lean-burn running limit.

Abstract: A method for automatically determining an engine oil change frequency at an engine control unit includes the steps of determining an amount of fuel used per oil change, and calculating an amount of fuel remaining from the fuel used per oil change. The method also includes the steps of comparing the amount of fuel remaining to a predetermined amount of fuel remaining, and actuating an oil change indicator if the fuel remaining is less than the predetermined amount of fuel.

Abstract: A method is provided for determining remaining oil life prior to an oil change in an internal combustion engine that uses a body of oil. The method includes transferring the body of oil to the engine and determining a volume of the transferred body of oil. The method also includes determining a volume of oil consumed by the engine from the transferred body of oil and determining the remaining oil life based on the determined volume of the body of oil and the determined volume of oil consumed. The method additionally includes activating an oil change indicator when the remaining oil life reaches a predetermined level. A system for determining a number of engine revolutions permitted on a volume of oil is also disclosed.

Abstract: A method is provided for determining remaining oil life prior to an oil change in an internal combustion engine that uses a body of oil. The method includes transferring the body of oil to the engine and determining a volume of the transferred body of oil. The method also includes determining whether an oil squirter is present in the engine. Additionally, the method includes determining the remaining oil life based on the determined volume of the body of oil and whether an oil squirter is present in the engine. Moreover, the method includes activating an oil change indicator when the remaining oil life reaches a predetermined level. A system for determining a number of engine revolutions permitted on a volume of oil is also disclosed.

Abstract: A method and apparatus for determining oil degradation measures a first electric-current value of a driving current used to operate an electric oil pump at a predetermined consistent revolution, and stores the first electric-current value as an electric-current initial value. Data is corrected by measuring a second electric-current value of the driving current, with the second electric-current value being measured when the electric pump is operated at the predetermined consistent revolution when the engine is driven a predetermined time after the electric-current initial value is stored. The electric-current initial value is compared with the second electric-current value. It is then determined that a viscosity of the oil has become low when a difference between the electric-current initial value and the second electric-current value is equal to or greater than a predetermined value.

Abstract: A system and method is employed to regulate a minimum transmission input speed based on automatic fluid temperature. The system includes a temperature sensor for sensing a temperature of the automatic transmission fluid and a controller for setting a minimum engine speed of the engine based on the temperature of the automatic transmission fluid. The size of a transmission pump may be reduced while the pump is still able to supply enough automatic transmission fluid to friction elements and gear ratios to provide lubrication and enable friction element actuators to engage and disengage the friction elements in a timely and effective manner. In a preferred form of the invention, when the temperature of the automatic transmission fluid is below 210° F., the minimum engine speed is set to no greater than 900 rpm; and when the temperature of the automatic transmission fluid is above 210° F., the minimum engine speed is set to no less than 1000 rpm.

Abstract: A cetane number estimation method is provided in which: the preliminary injection is preformed multiple times at different compression end temperatures with a fuel tank (26) containing fuel having a predetermined cetane number, and an engine torque increase caused by each preliminary injection is calculated and the relation between the compression end temperatures at the respective preliminary injections and the engine torque increases caused by the respective preliminary injections is determined; the compression end temperature and the engine torque increase at a predetermined reference point on the relation are recorded as a basic compression eng temperature and a basic engine toque increase; the preliminary injection is performed at the basic compression end temperature and an engine torque increase caused by this preliminary injection is calculated; and the cetane number of fuel is estimated based on the relation between the calculated engine torque increase and the basic engine torque increase.

Abstract: A minute amount of fuel is injected into a combustion chamber during fuel cut, and a cylinder pressure is detected when the minute amount of fuel is being combusted. Then a combustion ratio is calculated based on the detected cylinder pressure, and a determination crank angle, which is used for determining a cetane number based on the combustion ratio, is determined. The cetane number is determined based on the determination crank angle.

Abstract: A cetane number estimating device (1) comprises cylinders which are provided to an internal combustion engine where a part of the exhaust gas can be fed back from the exhaust system to the intake system, injection device (30) for injecting fuel into the cylinders, measuring device (40) for measuring the ignition timings in the cylinders, and estimating device (20) for estimating the cetane number of the fuel according to the measured ignition timing as well as any one of a first correlation between the ignition timing corresponding to the stage at which when one cylinder is in the intake stroke, another cylinder in the exhaust stroke exhausts non-burned gas and the cetane number and a second correlation between the ignition timing corresponding to the stage at which when one cylinder is in the intake stroke, another cylinder exhausts burned gas and the cetane number.

Abstract: A fuel temperature sensing device has fuel temperature sensors provided to respective cylinders for sensing fuel temperature. Each fuel temperature sensor is arranged in a position closer to an injection hole than to a pressure accumulator in a fuel passage extending from the pressure accumulator to the injection hole. The device has an average value calculating section for calculating an average value of fuel temperature sensing values sensed with the fuel temperature sensors of the respective cylinders. The device has a deviation calculating section for calculating deviations between the average value and the fuel temperature sensing values of the respective fuel temperature sensors. The device has a correcting section for correcting the fuel temperature sensing value of each fuel temperature sensor to approximate the deviation to zero for each fuel temperature sensor.

Abstract: A method is provided for determining remaining oil life prior to an oil change in an internal combustion engine that has a sump and uses a body of oil. The method includes transferring the body of oil to the engine and determining a volume of the transferred body of oil. The method also includes determining degradation of the determined volume of oil in response to oxidation and/or decomposition. The method additionally includes determining the remaining oil life based on the determined volume and degradation of the transferred body of oil. Furthermore, the method includes activating an oil change indicator when the remaining oil life reaches a predetermined level. A system for determining a number of engine revolutions permitted on a volume of oil is also disclosed.

Abstract: A fluid condition and level sensor is provided that includes a solenoid body, a coil, and an armature surrounded by the coil. The solenoid body defines an armature chamber in which the armature is movable in response to energizing of the coil. The sensor is mounted to a reservoir such that a first portion of the solenoid body extends into a cavity defined by the reservoir, and so that movement of the armature is substantially transverse to a direction of fluid level change in the reservoir. The first portion of the solenoid body defines an opening permitting fluid communication between the cavity and the armature chamber, such that fluid enters and is displaced from the armature chamber through the opening as the armature moves, movement of the armature within the armature chamber thereby being affected by fluid level in the reservoir.

Abstract: An alcohol concentration sensor detecting alcohol concentration of fuel is provided in a fuel tank or a fuel passage. An alcohol concentration detected at a previous driving of an engine is stored in a backup RAM. When a current alcohol concentration is different from the previous alcohol concentration, a procedure of an abnormality diagnosis is prohibited or invalidated until all of the fuel remaining in the fuel passage is consumed.

Abstract: A fluid level detection system includes a fluid reservoir defining a cavity for holding fluid therein. A fluid level sensor is mounted to the fluid reservoir. The solenoid body defines a first opening establishing fluid communication between an armature chamber and a cavity defined by the reservoir. Travel time of an armature within the armature chamber is thereby affected by fluid level in the reservoir. A controller is operatively connected to the sensor and is operable to receive a sensor signal indicative of travel time from the sensor and formulate a control signal corresponding thereto. A power source is operatively connected to the controller for energizing the coil and the controller. In some embodiments, multiple fluid containing components are connected with one or more controllers. An engine, a transmission, and rear axle differentials on a vehicle may be equipped with sensors to provide fluid level, temperature and viscosity information.

Abstract: A method for determining a deviation of a fuel quality from a reference quality and for determining a change in exhaust gas emissions caused by this deviation by evaluating pressure waves in a fuel system of an internal combustion engine outfitted with one of a discontinuous fuel delivery and a fuel take-off.

Abstract: Disclosed in certain embodiments is a method of determining the individual concentration of different antioxidants of the same class in a sample comprising contacting the sample with an effective amount of phenol; and analyzing the sample by voltammetry.

Abstract: A method of operating an internal combustion engine. The method including monitoring a pressure in a combustion chamber of the engine during a compression stroke, determining whether a fuel composition has changed from a first composition to a second composition based at least in part on the monitored pressure, and triggering a fuel composition adaptation in response to a determination that the fuel composition has changed.

Abstract: The invention relates to a measurement device (10), to a measurement method, to a monitoring apparatus (1) and a monitoring method for monitoring a state of wear of a component of a reciprocating piston internal combustion engine (2) including a cylinder (3) having a cylinder cover (4) and a running surface (51) provided at a cylinder wall (5) of the cylinder (3), in which cylinder (3) a piston (6) is arranged moveable to and fro in an axial direction (A) along the running surface (51) between a bottom dead center and a top dead center such that the piston (6), the cylinder cover (4) and the cylinder wall (5) form a combustion space (7) in the cylinder (3) for the combustion of a mixture of a fuel and air, wherein an oil collection device (8) is provided for the collection of lubrication oil (9) from the cylinder (3) so that a predetermined measured quantity (91) of lubrication oil (9) is suppliable from the cylinder (3) to a measurement device (10).

Abstract: A method is provided for determining remaining oil life prior to an oil change in an internal combustion engine that uses a body of oil. The method includes transferring the body of oil to the engine and determining a volume of the transferred body of oil. The method also includes determining whether an oil squirter is present in the engine. Additionally, the method includes determining the remaining oil life based on the determined volume of the body of oil and whether an oil squirter is present in the engine. Moreover, the method includes activating an oil change indicator when the remaining oil life reaches a predetermined level. A system for determining a number of engine revolutions permitted on a volume of oil is also disclosed.

Abstract: A method is provided for determining remaining oil life prior to an oil change in an internal combustion engine that uses a body of oil. The method includes transferring the body of oil to the engine and determining a volume of the transferred body of oil. The method also includes determining a volume of oil consumed by the engine from the transferred body of oil and determining the remaining oil life based on the determined volume of the body of oil and the determined volume of oil consumed. The method additionally includes activating an oil change indicator when the remaining oil life reaches a predetermined level. A system for determining a number of engine revolutions permitted on a volume of oil is also disclosed.

Abstract: A method is provided for determining remaining oil life prior to an oil change in an internal combustion engine that has a sump and uses a body of oil. The method includes transferring the body of oil to the engine and determining a volume of the transferred body of oil. The method also includes determining degradation of the determined volume of oil in response to oxidation and/or decomposition. The method additionally includes determining the remaining oil life based on the determined volume and degradation of the transferred body of oil. Furthermore, the method includes activating an oil change indicator when the remaining oil life reaches a predetermined level. A system for determining a number of engine revolutions permitted on a volume of oil is also disclosed.

Abstract: A method and control module for indicating engine oil life includes a viscosity determination module determining a viscosity of the engine oil based on an engine oil pressure and engine oil temperature. The control system further includes a comparison module comparing the viscosity of the engine oil to a threshold and generating a warning signal in response to comparing the viscosity.

Abstract: This invention is a method for determining the quality of lubrication oil added to a quantity of used oil in an operating engine or mechanism such as occurs during an oil change or when additional oil is added to maintain the vehicle manufacturer's specified total volume of oil. The method is based on identifying the electrical resistivity characteristics of the oil addition, representative of both the base oil formulation and its additive package, and, through comparison with previously-generated resistivity data on multiple oils identifying the oil addition. The added oil may then be compared with manufacturer specifications for the specific application to determine whether it meets recommended manufacturer requirements.

Abstract: In a fuel property detection device, a fuel housing is made of a thin-plate metal member that can be elastically-deformed by a fuel pressure in a fuel chamber. Thus, if the fuel pressure in the fuel chamber is increased, the fuel housing expands and the pressure in the fuel chamber is decreased. Further, if the fuel pressure in the fuel chamber is decreased, the fuel housing contracts and the pressure in the fuel chamber is increased. That is, the fuel housing functions as a kind of damper. Therefore, in the fuel property detection device, generation of abnormal noise due to fuel pulsation or the like, and a positional change of the electrodes due to the fuel pulsation or the like can be prevented.

Abstract: A system for simulating an engine environment during engine operation is disclosed. The system includes a surface. The system also includes a liquid delivery device configured to deliver a liquid to the surface. The system further includes a temperature controller operably coupled to the surface, and the system is configured to cause condensation of a fluid on the surface.

Abstract: A control unit executes sensing of a fuel property of fuel based on a physical value, which is related to a combustion state of the fuel in an internal combustion engine, when it is determined that a predetermined prerequisite operational condition for the sensing of the fuel property is satisfied upon occurrence of at least one of consumption of a predetermined amount of fuel, traveling of a vehicle through a predetermined travel distance, and execution of a predetermined number of operation cycle(s). The predetermined prerequisite operational condition may be satisfied when an operational state of the internal combustion engine is a deceleration fuel cut-off state or an idle state.

Abstract: A method for identifying a lubricant composition that reduces the propensity for knock in an engine. The lubricant composition is mixed with a solvent to reduce the viscosity of the lubricant composition, thereby forming a lubricant-solvent mixture having a viscosity similar to or less than that of engine fuel. A sample of a lubricant-solvent mixture is then subjected to a constant volume combustion test to determine the reactivity associated with the lubricant-solvent mixture. The test is repeated for a range of lubricant-solvent ratios, and statistical methods are used to calculate the reactivity of the lubricant composition without solvent.

Abstract: The present invention is to provide a machine tool in which appropriate warm-up operation can be performed. Unnecessary warm-up operation before machining is not carried out and damage of bearings caused by the warm-up operation is prevented. A controlling unit stores data of a supply amount of lubricant to bearings and a rotation speed of a main spindle in a memory unit as time-series data. When rotation of the main spindle is started, the time-series data stored in the memory unit is used to calculate an amount of remaining lubricant in the bearings and determination of necessity of warm-up operation is made based upon the stored data. A rotation speed at a start-up time of the main spindle is controlled according to the determination result.