Abstract: Techniques for managing metadata storage units involve: in response to receiving, from a client, a request for allocating a target number of metadata storage units, determining a first number of available metadata storage units remaining in a metadata storage space of a storage system after the allocation is performed; and if the first number is not less than a reserved number, allocating the target number of metadata storage units from the metadata storage space for the client to use, wherein the reserved number is associated with a usage condition of the metadata storage units in the storage system. Accordingly, such techniques can effectively manage metadata and improve the performance of a system.

Abstract: Techniques for managing a redundant array of independent disks (RAID) involve detecting an abnormality of a storage device in a RAID. The techniques further involve resetting the storage device in response to detecting the abnormality. The techniques further involve storing an address of a write operation for the RAID within a preset time period, so as to rebuild the RAID in the case that the storage device is recovered within the preset time period. Accordingly, temporary errors of the RAID can be efficiently handled, the number of downtime of the RAID caused by the storage device or the back end can be reduced, and computing resources and time required to rebuild the RAID can be significantly reduced.

Abstract: Techniques for managing a storage system involve: based on a degree of importance of data stored in a persistent storage device of the storage system, determining key data from the data, wherein a degree of importance of the key data is higher than a threshold degree; respectively identifying first data corresponding to the key data in a first cache of the storage system and second data corresponding to the key data in a second cache of the storage system as non-removable; and in response to corruption of the first data, repairing the first data using the second data in the second cache. Such techniques can avoid system shutdown caused by corruption of key data.

Abstract: Technology is disclosed for recovering the consistency of a RAID (Redundant Array of Independent Disks) metadata database when data corruption is detected in the RAID metadata database. The RAID metadata database includes super sectors, stage sectors, and a data region. Valid data within the data region is a contiguous set of sectors extending from a head sector to a tail sector. In response to data corruption in one of the two super sectors, a set of pointers contained in the other super sector is used to identify the head sector and tail sector. In response to data corruption in both super sectors, the head sector and tail sector are located based on the contents of the sectors in the data region. Techniques are also disclosed for recovering consistency when the data corruption occurs in the stage sectors and/or data region.

Abstract: Techniques for managing a redundant array of independent disks (RAID) involve detecting an abnormality of a storage device in a RAID. The techniques further involve resetting the storage device in response to detecting the abnormality. The techniques further involve storing an address of a write operation for the RAID within a preset time period, so as to rebuild the RAID in the case that the storage device is recovered within the preset time period. Accordingly, temporary errors of the RAID can be efficiently handled, the number of downtime of the RAID caused by the storage device or the back end can be reduced, and computing resources and time required to rebuild the RAID can be significantly reduced.

Abstract: Techniques for managing a storage system involve: based on a degree of importance of data stored in a persistent storage device of the storage system, determining key data from the data, wherein a degree of importance of the key data is higher than a threshold degree; respectively identifying first data corresponding to the key data in a first cache of the storage system and second data corresponding to the key data in a second cache of the storage system as non-removable; and in response to corruption of the first data, repairing the first data using the second data in the second cache. Such techniques can avoid system shutdown caused by corruption of key data, thereby optimizing system performance.

Abstract: Techniques for managing metadata storage units involve: in response to receiving, from a client, a request for allocating a target number of metadata storage units, determining a first number of available metadata storage units remaining in a metadata storage space of a storage system after the allocation is performed; and if the first number is not less than a reserved number, allocating the target number of metadata storage units from the metadata storage space for the client to use, wherein the reserved number is associated with a usage condition of the metadata storage units in the storage system. Accordingly, such techniques can effectively manage metadata and improve the performance of a system.

Abstract: Technology is disclosed for recovering the consistency of a RAID (Redundant Array of Independent Disks) metadata database when data corruption is detected in the RAID metadata database. The RAID metadata database includes super sectors, stage sectors, and a data region. Valid data within the data region is a contiguous set of sectors extending from a head sector to a tail sector. In response to data corruption in one of the two super sectors, a set of pointers contained in the other super sector is used to identify the head sector and tail sector. In response to data corruption in both super sectors, the head sector and tail sector are located based on the contents of the sectors in the data region. Techniques are also disclosed for recovering consistency when the data corruption occurs in the stage sectors and/or data region.

Abstract: Technology for configuration metadata recovery that detects a reliability failure regarding configuration metadata stored in non-volatile data storage of a data storage system. The configuration metadata indicates how a metadata database is stored in the non-volatile data storage of the data storage system. In response to detection of the reliability failure regarding the configuration metadata, the technology identifies valid generations of the configuration metadata that are currently stored in the non-volatile data storage of the data storage system, and determines a user-selected one of the valid generations of the configuration metadata. The metadata database is accessed based on the user-selected one of the valid generations of the configuration metadata.

Abstract: Techniques involve avoiding a potential failure event on a disk array. Along these lines, data collected for a disk array are obtained. It is determined, based on the collected data, whether a potential failure event is to occur on the disk array. In response to determining that the potential failure event is to occur on the disk array, an action to be taken for the disk array is determined, to avoid occurrence of the potential failure event.

Abstract: A method and system for estimating air mass per cylinder of an internal combustion engine is provided. An output signal from a MAF sensor is digitally processed to provide an estimate air mass per cylinder (APC). The system includes the MAF sensor; a data acquisition unit configured to receive an output signal from the MAF sensor and produce a sampled signal having a sampling rate greater than one sample per firing event; a multiple band pass (MBP) filter configured to remove signal components caused by airflow pulsations and oscillations through the MAF sensor; an envelope detector configured to detect the lower and upper envelopes of the MBP filtered signal; a MAF estimator configured to estimate a mass airflow based on the detected lower and upper envelopes; a signal decimator; a low pass filter; and a APC converter to converted the low pass filtered signal into an estimated APC.

Abstract: Techniques involve avoiding a potential failure event on a disk array. Along these lines, data collected for a disk array are obtained. It is determined, based on the collected data, whether a potential failure event is to occur on the disk array. In response to determining that the potential failure event is to occur on the disk array, an action to be taken for the disk array is determined, to avoid occurrence of the potential failure event.

Abstract: A vehicle system includes an engine defining a plurality of cylinders and configured to combust a fuel. A method of increasing efficiency of an engine includes controlling an amount of fuel being injected into the plurality of cylinders of the engine via a respective fuel injector. An exhaust gas recirculation (EGR) system is in selective fluid communication with a second subset of the plurality of cylinders and the air intake system to route the second exhaust product from the second subset of the plurality of cylinders to an air intake system. A valve is coupled to the EGR system and the exhaust system. A first sensor is disposed between the valve and the air intake system, and measures an amount of reformate in the second exhaust product when the valve is in a second position.

Abstract: A method and system for estimating air mass per cylinder of an internal combustion engine is provided. An output signal from a MAF sensor is digitally processed to provide an estimate air mass per cylinder (APC). The system includes the MAF sensor; a data acquisition unit configured to receive an output signal from the MAF sensor and produce a sampled signal having a sampling rate greater than one sample per firing event; a multiple band pass (MBP) filter configured to remove signal components caused by airflow pulsations and oscillations through the MAF sensor; an envelope detector configured to detect the lower and upper envelopes of the MBP filtered signal; a MAF estimator configured to estimate a mass airflow based on the detected lower and upper envelopes; a signal decimator; a low pass filter; and a APC converter to converted the low pass filtered signal into an estimated APC.

Abstract: A fuel vapor control system for a vehicle includes a fuel vapor canister that traps fuel vapor from a fuel tank of the vehicle. A purge valve opens to allow fuel vapor flow to an intake system of an engine and closes to prevent fuel vapor flow to the intake system of the engine. An electrical pump pumps fuel vapor from the fuel vapor canister to the purge valve. A vent valve allows fresh air flow to the vapor canister when the vent valve is open and prevents fresh air flow to the vapor canister when the vent valve is closed. A purge control module controls a speed of the electrical pump, opening of the purge valve, and opening of the vent valve.

Abstract: An exhaust aftertreatment system including a selective catalytic reduction device (SCR), a NOx sensor and a reductant injection system is described. A method for controlling the reductant injection system to inject reductant into the exhaust gas feedstream upstream relative to the SCR includes monitoring engine operation, and determining an initial reductant dosing rate responsive to the engine operation. A dosing perturbation is induced in the reductant dosing rate. The exhaust gas feedstream is monitored via the NOx sensor, and a reductant dosing correction term is determined based upon the monitoring. A final dosing rate for controlling the reductant injection system is determined based upon the initial reductant dosing rate, the dosing perturbation, and the reductant dosing correction term.

Abstract: An exhaust aftertreatment system including a selective catalytic reduction device (SCR), a NOx sensor and a reductant injection system is described. A method for controlling the reductant injection system to inject reductant into the exhaust gas feedstream upstream relative to the SCR includes monitoring engine operation, and determining an initial reductant dosing rate responsive to the engine operation. A dosing perturbation is induced in the reductant dosing rate. The exhaust gas feedstream is monitored via the NOx sensor, and a reductant dosing correction term is determined based upon the monitoring.

Abstract: A method for controlling a turbine of an engine system to achieve a desired boost pressure is provided. The method determines a desired exhaust gas pressure based on the desired boost pressure by using a model for a power balance between the turbine and a compressor of the engine system. The method generates a base command for controlling a position of a vane of the turbine based on a ratio of the desired exhaust gas pressure to a measured turbine outlet pressure.

Abstract: A fuel vapor control system for a vehicle includes a fuel vapor canister that traps fuel vapor from a fuel tank of the vehicle. A purge valve opens to allow fuel vapor flow to an intake system of an engine and closes to prevent fuel vapor flow to the intake system of the engine. An electrical pump pumps fuel vapor from the fuel vapor canister to the purge valve. A vent valve allows fresh air flow to the vapor canister when the vent valve is open and prevents fresh air flow to the vapor canister when the vent valve is closed. A purge control module controls a speed of the electrical pump, opening of the purge valve, and opening of the vent valve.

Abstract: A method is provided for generating rapid light-off for a diesel oxidation catalyst (DOC) close-coupled to a compression-ignition engine. The engine includes an intake passage in fluid communication with a combustion chamber, a throttle for controlling a flow of intake air through the intake passage, and an exhaust passage configured to channel an exhaust gas from the combustion chamber to the DOC. The method includes starting the engine to commence a warm-up thereof and regulating the throttle to restrict supply of the intake airflow to the combustion chamber. The method additionally includes injecting a predetermined amount of fuel into the combustion chamber during the engine's exhaust cycle such that the injected fuel is carried by the exhaust gas and burned in the exhaust passage. Regulating the throttle and injecting fuel during the warm-up of the engine together increase temperature of the exhaust gas for rapid light-off of the close-coupled DOC.