Abstract: A method for automatically operating a cam-driven pump is disclosed. The pump is monitored to determine whether a specified detachment condition or potential detachment of an actuator of the pump from a driving cam is occurring. The pump is operated in a minimal pressure holding mode to provide a minimal pressure within a working chamber of the pump so as to bias the actuator towards the cam if it is determined that the detachment condition is occurring.

Abstract: An air flow velocity calculating device of a internal combustion engine, has a cylinder, a spark plug, an air intake passage, an air flow controlling valve, an air flow velocity calculating portion, and an electric discharge current controlling portion. An electric discharge between a center electrode and a ground electrode is sustained during an electric discharge sustaining period. The electric discharge sustaining period is a period from when the electric discharge begins to when the electric discharge is intercepted by the air flow. Energy is supplied to the spark plug, so that the electric discharge current is sustained at a constant value by the electric discharge current controlling portion during an ignition period.

Abstract: An engine includes a cylinder body, a cylinder head, and an ignition device including spark plugs. The engine also includes an intake device connected to intake ports, an exhaust device connected to exhaust ports, pistons, and a crankshaft connected to the pistons by connecting rods. Explosion intervals of the cylinders are 270°, 180°, 90°, and 180° as crank angles. The engine further includes a discomfort eliminator which, when the engine speed is lower than a predetermined value, makes the indicated mean effective pressure of at least one of two cylinders having an explosion interval of 90° lower than the indicated mean effective pressures of the other cylinders having an explosion interval of not 90°. The engine causes unequal-interval explosions but produces little change in the driving energy per unit time during an operating state in which an occupant is liable to feel torque fluctuations.

Abstract: A control device for an internal combustion engine includes an in-cylinder pressure detector, an output shaft torque calculator, a target torque calculator, an input torque parameter calculator, and a controller. The output shaft torque calculator is to calculate an output shaft torque of an output shaft of the internal combustion engine based on an in-cylinder pressure. The target torque calculator is to calculate a target torque of the output shaft torque. The input torque parameter calculator is to calculate an input torque parameter representing an input torque such that the output shaft torque becomes equal to the target torque using a feedback control algorithm which is based on a controlled object model which models a controlled object that receives the input torque parameter as input and produces the output shaft torque as output. The controller is to control the output shaft torque using the input torque parameter.

Abstract: A system according to the principles of the present disclosure includes a switching period module and at least one of a valve lift control module and a start-stop control module. The switching period module determines a switching period that elapses as a valve lift actuator of an engine switches between a first valve lift position and a second valve lift position that is different than the first lift position. The switching period begins when a measured position of the valve lift actuator corresponds to the first lift position and the switching period ends when the measured position of the valve lift actuator corresponds to the second lift position. The valve lift control module controls the valve lift actuator based on the switching period. The start-stop control module determines whether to automatically stop the engine based on the switching period.

Abstract: In a vehicle with an automatic transmission, an internal combustion engine is provided with a variable compression ratio mechanism. A target compression ratio of the variable compression ratio mechanism is determined based on a demand load and an engine rotation speed with reference to a compression ratio map. A reverse-drive compression ratio map is selected when the automatic transmission is in a reverse drive position; a first compression ratio map is selected when an actual speed reduction ratio of the transmission is low; and a second compression ratio map is selected when the actual speed reduction ratio of the transmission is high. A variable control range of the compression ratio is narrower in the second compression ratio map than in the first compression ratio map and is narrower in the reverse-drive compression ratio map than in the first and second compression ratio maps.

Abstract: Techniques for measuring cylinder pressure include receiving an analog cylinder pressure signal indicative of pressure in a cylinder of an engine and an angular position signal indicative of an angular position of the engine. The analog cylinder pressure signal is converted to a digital cylinder pressure signal by (i) windowing the analog cylinder pressure signal in the angle-domain using the angular position signal and (ii) sampling the windowed analog cylinder pressure signal in the time-domain, and the digital cylinder pressure signal is filtered in the time-domain to obtain a filtered digital cylinder pressure signal. A measured pressure in the angle domain is obtained by sampling the filtered digital cylinder pressure signal using the angular position signal, and operation of the engine is controlled using the measured cylinder pressure.

Abstract: Provided are a knocking determination device and a knocking control device for an internal combustion engine, with which a large amount of knocking can be detected quickly and with which knocking is easily determined. A knocking time window and a bandpass filter (BPF) are used (B1-B2) to extract a knocking frequency waveform signal from a knock sensor signal (Sg1), and integration is performed to obtain a first calculated value (B3). A reference time window and a BPF are used (B4-B5) to extract a reference frequency waveform signal from the knock sensor signal (Sg1), and integration is performed to obtain a second calculated value (B6). The average value of multiple instances of the second calculated value is obtained (B7), and the first calculated value is divided by the average value to obtain a signal-to-noise (S/N) ratio (B8).

Abstract: Various systems and methods are provided for identifying cylinder misfire. In one example, cylinder misfire may be identified based on a misfire monitor that differentiates a single-cylinder misfire event from a multi-cylinder misfire event based on output from a crankshaft speed sensor.

Abstract: A control apparatus for an internal combustion engine having an exhaust gas purification device which is arranged in an exhaust passage and includes a NOx storage reduction (NSR) catalyst. The control apparatus, when the air fuel ratio of the air-fuel mixture is shifted from a lean air fuel ratio to the stoichiometric air fuel ratio, determines a predetermined NOx amount so as to be larger when the temperature detected by the first detection unit is high in comparison with when the detected temperature is low, and when the storage amount of NOx in the NSR catalyst is larger than the predetermined NOx amount, performs the rich spike processing and then controls the air fuel ratio to the stoichiometric air fuel ratio, whereas when otherwise, controls the air fuel ratio to the stoichiometric air fuel ratio without performing the rich spike processing.

Abstract: Methods and systems are presented for assessing the presence or absence of engine torque deviation which may indicate air-fuel ratio imbalance between engine cylinders. In one example, the method may include assessing the presence or absence of engine torque variation based on engine torque deviation from a desired engine torque during a deceleration fuel shut-off event.

Abstract: A method and system for blending between different torque maps of a vehicle so that step changes of torque output are avoided as accelerator pedal position is changed. Different blending rates are provided so as to reduce the blending time if driver demand is in the direction of torque change.

Abstract: Fuel injector wear methodologies for use with internal combustion engines include a method that determines power of the engine and/or fuel flow of a fuel injector(s) associated with a cylinder the engine; obtains a duration of a fuel injection event from the injector(s) associated with the cylinder(s) of the engine; compares the power, the fuel flow, and/or the duration with a reference value; and then adjusts the fuel injection timing of the fuel injector(s), based on the comparison. Another method adjusts operation of an engine includes: comparing two (or more) engine models, wherein one model is related to a fuel injection event duration of the engine or a modeled fuel quantity being supplied to the engine and then adjusting the fuel injection timing of a fuel injector(s) of the engine, based on the comparison.

Abstract: A drive current applied to a coil is reduced from a time at which a first collision signal indicating collision of a movable core with a valve element is input to a time at which a second collision signal indicating collision of the movable core with a stationary core is input.

Abstract: A fuel injection control apparatus is provided with a first valve opening timing determination portion that determines a first valve opening timing on the basis of a collision signal that is included in detected signals of an in-cylinder pressure sensor and indicates a collision between a movable core and a valve element and a second valve opening timing determination portion that determines a second valve opening timing on the basis of another collision signal that is included in the detected signals and indicates a collision between the movable core and a stationary core.

Abstract: Fuel injector wear compensation methodologies for use with internal combustion engines that alter the injection schedule over the life of the fuel injector(s) by using methods that conduct a primary injection of fuel in the engine (primary fuel event), per an injection schedule within an engine cycle; compare a measured engine parameter(s) to a reference value(s); and then alter the injection schedule applied to the engine, based on the comparing. Another method comprises: during injection events, inject a first fuel in a combustion chamber of the engine; measure an engine parameter(s) of the engine during operation; compare the engine parameter(s) to a reference value(s); add a post injection event of a second fuel during the injection events, based on the comparison. The methods can be applied with single or dual fuels.

Abstract: An engine system and method for adjusting pressure of fuel supplied to an engine responsive to compressibility of fuel supplied to the engine is disclosed. In one example, the engine is operated with a fuel pump in an off state to determine compressibility of fuel supplied to the engine. Fuel pressure supplied to the engine is adjusted responsive to the fuel compressibility.

Abstract: An engine is mounted in a vehicle configured to perform EV travelling. The engine includes a port injection valve that injects fuel to an intake port, a low pressure delivery pipe that stores the fuel for injection from the port injection valve, and a feed pump that compresses and thus supplies the fuel to the low pressure delivery pipe. An ECU, in the EV travelling, starts the fuel pump when a vehicle request power representing a driving power of the vehicle requested by the user exceeds a pump threshold value, and the ECU, in the EV travelling, generates a request to start the engine when the vehicle request power exceeds an engine threshold value larger than the pump threshold value.

Abstract: An object is to achieve stable diesel combustion and improvement in the thermal efficiency of the diesel combustion in an internal combustion engine using a fuel having a relatively high self-ignition temperature. A control apparatus for an internal combustion engine includes a fuel injection valve capable of injecting fuel into a combustion chamber and an ignition device whose position relative to the fuel injection valve is set in such a way that it can ignite fuel spray directly. The apparatus causes pre-injected fuel to burn and generates unburned residue of the pre-injected fuel in the combustion chamber by pre-injection performed at a predetermined pre-injection time during the compression stroke and ignition of pre-spray formed by the pre-injection by the ignition device.

Abstract: An object is to achieve stable diesel combustion and improvement in the thermal efficiency of the diesel combustion in an internal combustion engine using a fuel having a relatively high self-ignition temperature. A control apparatus for an internal combustion engine includes a fuel injection valve capable of injecting fuel into a combustion chamber and an ignition device whose position relative to the fuel injection valve is set in such a way that it can ignite fuel spray directly. The apparatus performs pre-injection at a predetermined pre-injection time during the compression stroke and main injection at a predetermined injection start time after pre-spray formed by the pre-injection is ignited by the ignition device, thereby causing self-ignition to occur and causing at least a portion of the main-injected fuel to burn by diffusion combustion. When the quantity of the pre-injected fuel is increased, the pre-injection time is advanced responsive to the increase in the quantity of the pre-injected fuel.

Abstract: A control device for a compression-ignited internal combustion engine includes a nozzle that includes plural injection holes arranged at intervals in the circumferential direction and that directly injects fuel to a combustion chamber, a piston that includes a cavity with an inner circumferential side surface to which a distance from the nozzle varies in the circumferential direction, a first injection hole for injecting fuel to a portion of the inner circumferential side surface to which the distance from the nozzle is the largest out of the plural injection holes, a second injection hole for injecting fuel to a portion of the inner circumferential side surface to which the distance from the nozzle is the smallest out of the plural injection holes, a detection unit that detects a heat release rate in the combustion chamber, and a control unit that determines which of the first and second injection holes is abnormal.

Abstract: The cylinder head includes: an intake port; a low-temperature cooling water channel for circulating low-temperature cooling water; a high-temperature cooling water channel for circulating cooling water of a higher temperature than the cooling water flowing through the low-temperature cooling water channel; and a gas channel for recirculating a portion of blow-by gas or EGR gas to the intake port. The low-temperature cooling water channel is configured to include a first water jacket that covers at least one portion of the wall surface of the intake port on an intake-air upstream side relative to an opening end opening at a wall surface of the intake port from the gas channel.

Abstract: The present disclosure provides an apparatus for improving engine air flow including: a combination recess which is formed at an intake port of a cylinder head and is extended toward a combustion chamber along an air flow path at a position combined with an intake manifold; a fixing body which is fit-inserted to and combined to the combination recess; and a plate an end of which is combined to the fixing body on the flow path of the intake port and which guides the air flow flowing into the intake port.

Abstract: A variable area fan nozzle actuation (“VAFN”) system is disclosed. The VAFN system may include an electrohydrostatic actuator (“EHA”) arranged to translate a VAFN panel relative to a translating sleeve. An electrical coupling may extend between a translating sleeve associated with the VAFN system and the fixed structure. The electrical coupling may be movable so that as the translating sleeve and fixed structure move relative to each other, power may be provided to the EHA by a wiring harness extending across the space between the translating sleeve and the fixed structure and connecting the EHA to an EHA power source.

Abstract: The passive edge-tone suppression method includes the step of inserting a central insertion tube within a nozzle to disturb jet oscillations in a flow field of an edge-tone feedback loop. The central insertion tube can have a diameter of 200 micrometers and can be inserted within a center of the nozzle. The method also includes the step of extending the central insertion tube through the nozzle and into an alignment with the edge producing the edge tone. Further, the method includes the step of increasing a length of the central insertion tube in relation to a stand-off distance between the nozzle and the edge. The length of the central insertion tube can be increased to a length of about 30 percent of the stand-off distance.

Abstract: A hydraulic control system of a thrust reverser for a turbojet engine nacelle includes a hydraulic machine fed by a pressure source, which motorizes actuators carrying out the thrust reverser stroke, wherein the hydraulic machine includes a variable displacement.

Abstract: A track lock assembly is described herein according to various embodiments. The track lock assembly may comprise a translating sleeve, a track beam, a pivoting lock assembly, and a ramp. In various embodiments, the pivoting lock assembly may be mounted to the translating sleeve, wherein in response to the pivoting lock being mounted to the translating sleeve, the ramp is mounted to the track beam. In various embodiments, the pivoting lock assembly may be mounted to the track beam, wherein in response to the pivoting lock being mounted to the track beam, the ramp is mounted to the translating sleeve.

Abstract: A post launch pressurized gas production system and method includes a cell containing a pressurized gas producing medium, such as anhydrous sodium bicarbonate producing CO2 gas when heated. A plenum tank is in fluid communication with the cell. A heater heats the cell to produce gas delivered to the plenum tank storing the gas therein under pressure. A pressure vessel includes a propellant therein pressurized by the gas and in fluid communication with a thruster for delivery of the propellant to the thruster after pressurization by the gas.

Abstract: Embodiments of an internal combustion engine are provided. In one example, an engine includes at least one cylinder, an intake system for supplying charge air to the at least one cylinder, an exhaust-gas discharge system for discharging exhaust gas from the at least one cylinder, a first exhaust-gas turbocharger including a first turbine arranged in the exhaust-gas discharge system and a first compressor arranged in the intake system; and an exhaust-gas recirculation (EGR) system. The EGR system includes a line which branches off from the exhaust-gas discharge system and opens into the intake system, a second exhaust-gas turbocharger comprising an EGR turbine arranged in the line on a shaft and an EGR compressor arranged in the line on the shaft upstream of said EGR turbine, and an EGR cooler positioned between the EGR turbine and the EGR compressor.

Abstract: Provided is a catalytic converter to be disposed in a branch portion between an exhaust gas passage that guides exhaust gas from an internal combustion engine to outside and an exhaust gas recirculation passage that recirculates a portion of the exhaust gas from the exhaust gas passage to an intake system of the internal combustion engine. The catalytic converter comprises a catalyst storage case that stores a catalyst, a recirculation pipe that forms the exhaust gas recirculation passage, an abutment portion that makes the catalyst storage case and the recirculation pipe be in surface contact with each other and be arranged in parallel to each other, and a downstream cone that makes the exhaust gas passage and the exhaust gas recirculation passage merge with each other.

Abstract: An EGR device is operated and EGR is executed, when a temperature of a first cooling water that cools a cylinder block and a cylinder head is higher than an EGR allowable temperature, and a working point of the internal combustion engine that is fixed by a load and an engine speed is in an EGR execution region. The EGR execution region is variable with respect to a temperature of the second cooling water (the temperature of the second cooling water is lower than the first cooling water) that cools the intake port, and the EGR execution region is narrowed to a high load side in a case where the temperature of the second cooling water is lower than a threshold value temperature, as compared with a case where the temperature of the second cooling water is higher than the threshold value temperature.

Abstract: A method of providing internal EGR to an engine having at least one dedicated EGR cylinder. The main (non dedicated) cylinders are operated with internal EGR, in addition to external EGR from the dedicated EGR cylinder. The dedicated EGR cylinder has separate valve control so that it need not be operated with internal EGR, thereby allowing it to be operated at a richer air-to-fuel ratio.

Abstract: A mixer to mix a fuel with air includes plural fluid inlets, at least one fluid outlet, a casing, a plurality of stirring blades, and a particle material or a porous material. The casing has a substantially tubular shape extending in an axial direction of the casing between the plural fluid inlets and the at least one fluid outlet. The plurality of stirring blades are provided in the casing to align in the axial direction so that a torsional turning direction of the plurality of stirring blades is sequentially reversed in an order of alignment. The particle material or a porous material is disposed in the casing to fill an entire space containing the plurality of stirring blades from the plural fluid inlets to the at least one fluid outlet. Sizes of gaps existing in the entire space are less than a quenching distance of the fuel.

Abstract: An intake sound introducing apparatus has, for example, a branch pipe, a sound creator, a communication pipe, and a resonator. The branch pipe branches from an intake pipe of the engine. The sound creator includes a vibrator that vibrates with the intake pulsation of the intake sound propagating within the branch pipe. The communication pipe provides communication between the inside of a casing of the sound creator and the inside of the cabin. The resonator is provided in the communication pipe.

Abstract: A fuel pump may be driven by a brushless motor. The fuel pump may include a core; three supplying terminals configured to supply electric power to a coil wire fixed to the core and wound around the core; a resin layer holding the three supplying terminals; and a ground terminal held by the resin layer in a state of being insulated from the three supplying terminals, wherein the ground terminal may be electrically connected to a control circuit configured to control electric power supplied to the three supplying terminals.

Abstract: A fuel supply system for an internal combustion engine may include a plurality of fuel injection pumps, each fuel injection pump being configured to pressurize fuel and provide the pressurized fuel to an associated fuel injector. The fuel supply system may further include a low-pressure fuel supply line fluidly connected to the plurality of fuel injection pumps and configured to provide fuel from a fuel supply tank to the plurality of fuel injection pumps. The fuel supply system may still further include a low-pressure fuel return line fluidly connected to the plurality of fuel injection pumps and configured to return remaining fuel from the plurality of fuel injection pumps to the fuel supply tank. The fuel supply system may include a first fuel cut-off valve disposed in the low-pressure fuel supply line and configured to stop a flow of fuel from the fuel supply tank to the plurality of fuel injection pumps.

Abstract: A fuel injector for delivering vaporized or aerosolized fuel mixtures to a spark ignited internal combustion engine.

Abstract: A connecting device for fuel injection systems is used for joining a fuel injector to a cup and to a fuel-conveying component. In this context, connecting elements are provided, which are insertable into the cup in such a manner, that they are situated at least approximately in one plane, which is oriented perpendicularly to a longitudinal axis of a cup. Connecting elements take the form of pin-shaped connecting elements. In addition, the connecting elements are formed in such a manner, that they are inserted into the cup, inside an outer cross-section of the cup. A securing element is also provided for securing the connecting elements. Furthermore, a fuel injection system having such a connecting device is provided.

Abstract: Methods are provided for controlling a solenoid spill valve of a direct injection fuel pump, wherein the solenoid spill valve is energized and de-energized according to certain conditions. An example control strategy is provided for operating the direct injection fuel pump when fuel vapor is detected at an inlet of the direct injection fuel pump. To ensure pump effectiveness during the presence of fuel vapor, the solenoid spill valve may be maintained energized for a minimum angular duration past a top-dead-center position of a piston in the direct injection fuel pump.

Abstract: A fuel injection valve includes a housing having a nozzle hole, a valve seat, and a fuel passage; a needle that is accommodated in the housing to be capable of reciprocating in an axial direction of the housing and that opens or closes the nozzle hole; a coil; a fixed core; a movable core; a shift permitting member that is provided between the housing and an internal-combustion engine to permit a shift of an attachment position at time of attachment of the housing and the engine; and a friction reducing part that is provided between the engine and the shift permitting member to reduce friction between the engine and the shift permitting member. The friction reducing part permits displacement of the housing in a direction perpendicular to the axial direction of the housing.

Abstract: The present disclosure generally relates to nozzles for a valve and, more specifically, to a fuel injection valve for a combustion engine. In some embodiments, a nozzle assembly for a fuel injection valve for a combustion engine may include: a valve body with a central longitudinal axis; a valve cavity within the valve body; a nozzle tip body comprising a protrusion limiting a free volume of the valve cavity; and at least one nozzle aperture out from the valve cavity through the protrusion. The protrusion may extend from an end surface of the nozzle tip body in an extending direction parallel to a longitudinal axis of the nozzle tip body away from the valve cavity and comprise a first section adjacent to the end surface, the first section having a cylindrical outer surface, and a second section adjacent to the first section, the second section having an outer surface of decreasing diameter in the course away from the end surface along the extending direction.

Abstract: A fuel pipe of a fuel supply device includes: a first side wall having a mounting surface to which an injector cup and a bracket are attached; and a second side wall to which the injector cup and the bracket are not attached. A peripheral wall of the injector cup extends at least from a position on a bottom-end side relative to a centerline in a mounting surface to a position on an upper-end side relative to the centerline, and is fixed to the mounting surface at a part of the mounting surface on the bottom-end side relative to the centerline and at a part thereof on the upper-end side relative to the centerline.

Abstract: A crank permission system includes first and second permission modules and a crank module. The first permission module selectively generates a first permission signal, based on a first gear range engaged within a transmission, when an ignition system transitions to crank. The second permission module selectively generates a second permission signal, based on (i) the first gear range stored when the ignition system last transitioned to off and (ii) a second gear range of the transmission requested by a driver using a transmission range selector, when the ignition system transitions to crank. The crank module begins cranking an engine via a starter, in response to the generation of at least one of the first and second permission signals, when the ignition system of the vehicle transitions to crank.

Abstract: A priming system for an engine system having a throttle valve configured to regulate a flow of air and fuel into an intake manifold of an engine is disclosed. The priming system may include a first sensor configured to generate a signal indicative of an engine speed, an auxiliary fuel line configured to direct fuel from a fuel source to a location between an outlet of the throttle valve and the intake manifold, an auxiliary fuel valve disposed in the auxiliary fuel line, and a controller in communication with the first sensor and the auxiliary fuel valve. The controller may be configured determine the engine speed based on the first signal and close the auxiliary fuel valve when the engine speed is greater than or equal to a threshold engine speed. The threshold engine speed may be less than an idle speed of the engine.

Abstract: A motor vehicle heat exchanger system includes a closed circuit for a working medium and an exhaust gas channel for passage of exhaust gas that is discharged from an internal combustion engine of the motor vehicle. An evaporator makes contact with the exhaust gas channel and evaporates the working medium. The evaporator includes at least one evaporator cassette having a housing and a capillary structure arranged in the housing. The capillary structure is formed by a porous plate body, e.g. made of sintered material.

Abstract: The invention relates to hydraulic systems with constant delivery of fluid under pressure, using continuous balancing of pressures generated by liquid accumulated in a reservoir and coming from a collecting system. The system converts motion of liquid to operate individual high-pressure pumps, which pump water through water pipes from a natural body of water into the reservoir above sea level. A device for pressure conversion of the flow of water coming through the water duct from the reservoir in the consumption energy for the production of useful work. Tanks are at the bottom of the reservoir and connected to high-pressure pumps that pump water at high pressure, and which are equipped with pressure accumulators to normalize the pressure. A buffer vessel at the bottom of water duct, below the reservoir and above the sea level, is equipped with pressure accumulators.

Abstract: A rolling-door-type load regulating device and an ocean energy power generating device using the same are described herein. The rolling-door-type load regulating device includes a water guiding unit, a roller spindle, and a driver. The water guiding unit includes at least two water guiding plates connected in parallel. The roller spindle is fixed to one end of the water guiding unit. The driver is connected with the roller spindle and drives the roller spindle to rotate to spread or retract the water guiding unit. The rolling-door-type load regulating device in the invention can regulate the load suffered by the hydraulic turbine. Therefore, the power generated by the ocean energy power generating device can be stably output and be directly used, thereby solving the problem that the output power of the conventional ocean energy power generator has wide fluctuations and poor stability.

Abstract: A wave energy convertor for extracting energy from ocean waves. The wave energy convertor may include a buoy arranged to oscillate relative to a reference point about an equilibrium position and a negative spring device connected between the buoy and the reference point, wherein the negative spring device is for applying a positive force in the direction of displacement when the buoy moves away from the equilibrium position.

Abstract: A wave energy converter can be dynamically tuned to achieve resonance with ocean swell by varying the geometry of an attached submerged water-filled vessel (41).

Abstract: A water current power generating system includes a support structure located on a bed of a body of water. A power generating apparatus, such as a water current turbine device, is mounted on the support structure, by way of a mounting portion. The system also includes a measurement unit operable to determine operating information relating to operation of the system, and a controller operable to determine loading on the system from such operating information, and to adjust a controlled parameter of the system such that loading on the system falls below a predetermined threshold value.