A species-specific gas sensor and monitor comprising a light source, a sample enclosure or measurement chamber, an optical interface between the light source, the sample and the detection system, electronics that integrate the light source and the detection system, and computational components, such as an onboard microprocessor for calculation of the gas composition and communications between the sensor and the vehicle electronics. The species-specific gas sensor of the present invention can be used to target gases, such as nitric oxide (NO), nitrogen dioxide (NO.sub.2) ammonia (NH.sub.3), and sulfur dioxide (SO.sub.2) which are measurable in the UV spectrum.

A gas analyzer via which exhaust gas to be analyzed is conducted untreated through a first measurement chamber and, after treatment in an oxidation device, through a second measurement chamber, wherein ozone is produced from oxygen to thereby convert nitrogen monoxide into nitrogen dioxide, where the gas analyzer has a first light emitting diode and a second light emitting diode, light of both diodes is conducted through the first measurement chamber onto a first detector, light of the first light emitting diode is partly conducted through the second measurement chamber onto a second detector via a beam splitter arrangement, based on the first detector signal, the nitrogen dioxide concentration of the untreated gas is also measured, based on the second detector signal, the nitrogen dioxide concentration of the treated exhaust gas is measured, and the nitrogen oxide concentration of the exhaust gas is additionally determined from measured nitrogen dioxide concentrations.

In order to separately evaluate an influence degree of fuel and an influence degree of lubricating oil with respect to particulate matters contained in exhaust gas, an exhaust gas analysis method includes: analyzing particulate matters contained in the exhaust gas exhausted from an engine, thereby making it possible to analyze the particulate matters derived from the lubricating oil by using isooctane as a fuel.

The present invention is provided with: a SOx purge control unit that executes catalyst regeneration processing that maintains the temperature of a NOx occlusion/reduction catalyst at a prescribed recovery temperature; a catalyst temperature estimation unit that estimates catalyst temperature on the basis of the amount of unburnt fuel contained in exhaust and of a catalyst heat generation amount; a second exhaust temperature sensor that is arranged further to an exhaust downstream side than the catalyst and that detects exhaust temperature; and a heat generation amount correction value setting unit that, during the execution of the catalyst regeneration processing, on the basis of an estimated catalyst temperature estimated by the catalyst temperature estimation unit and of an actual exhaust temperature detected by the second exhaust temperature sensor, obtains a heat generation amount correction value that is used to correct the heat generation amount of the catalyst.

Gas treatment systems and processes for reducing tail gas emissions such as SO.sub.2, SO.sub.3, H.sub.2SO.sub.4, NOx, HC, CO, and other pollutants are provided. The processes include transferring tail gas from at least one source of tail gas to at least one destination sulphuric acid plant via a tail gas transfer system, wherein the tail gas replaces or supplements one or more of the combustion gas, air feed, dilution gas, and quench gas used by the destination sulphuric acid plant. The systems include at least one destination sulphuric acid plant and a tail gas transfer system for transferring tail gas from at least one source of tail gas to the at least one destination sulphuric acid plant. The systems and processes described herein may be used to eliminate start-up emissions and/or convert sulphur-containing species present in tail gas emissions into commercial H.sub.2SO.sub.4.

A gas detector includes a measurement control section that controls a voltage application section, obtains an output current flowing between a first electrode and a second electrode of an electrochemical cell, and detects a concentration of sulfur oxides in exhaust gas based on the output current. The measurement control section uses a minimum value of the output current obtained by using a current detection section in a period in which lowering sweep is executed and in which an applied voltage is a voltage within a detection voltage range that is equal to or lower than a decomposition initiation voltage of sulfur oxides as a parameter used for detection of the concentration of sulfur oxides.

A gas detection device includes: an element portion; a voltage applying unit configured to apply a voltage across a first electrode and a second electrode on surfaces of a solid electrolyte; a current detecting unit configured to detect an output current flowing between the first electrode and the second electrode; and a measurement control unit. The measurement control unit acquires a parameter which has a correlation with a degree of change of the output current increasing as a concentration of sulfur oxides in an exhaust gas increases based on the output current, and performs determination of whether the concentration of sulfur oxides in the exhaust gas is equal to or higher than a predetermined value or detection of the concentration of sulfur oxides in the exhaust gas based on the acquired parameter.

A gas detection device includes a temperature control part configured to control an amount of energization to a heater so that an impedance of an element part matches a target impedance, to thereby control a temperature of the heater. The temperature control part is configured to set a first target impedance as the target impedance while performing application voltage control for air-fuel ratio detection, and set a second target impedance as the target impedance while performing application voltage control for SOx detection.

The present invention identifies substances which suppress odors of sulfide compounds. Provided is a method for evaluating and/or selecting an agent for suppressing odors of sulfide compounds, the method comprising: adding a test substance and a sulfide compound to at least one olfactory receptor polypeptide selected from the group consisting of OR4S2 and polypeptides having an amino acid sequence identity of at least 80% to OR4S2; and measuring the response of the olfactory receptor polypeptide to the sulfide compound.

A control system for an engine including a limiting current sensor, the control system includes an ECU configured to: execute a sweep process for gradually reducing a voltage that is applied to the sensor from a first voltage a second voltage; acquire an extreme value of an output current of the sensor during execution of the sweep process from output currents of the sensor while a voltage included in a specific voltage range is applied to the sensor, the extreme value being predicted to be output; and detect the concentration of SOx in exhaust gas based on the extreme value and a reference value, the reference value being a value of limiting current of the sensor, the value of limiting current of the sensor corresponding to the concentration of oxygen having the constant value.