A method of analyzing fuel component using an RF (Radio Frequency) sensor for a vehicle includes: receiving a new fuel into a fuel tank so as to mix existing fuel in the fuel tank with the new fuel, measuring a resonance frequency of the mixed fuel using an RF sensor, comparing the measured resonance frequency of the mixed fuel with a resonance frequency of a standard fuel, determining whether the mixed fuel is a normal fuel through the comparison, maintaining an engine combustion pattern corresponding to the standard fuel when the mixed fuel is a normal fuel, and operating reflecting an engine combustion control.

Methods and systems are provided for an exhaust gas arrangement. In one example, a system comprises an air supply device arranged between a first LNT and a second LNT. The air supply device positioned to adjust an air/fuel ratio and a temperature of exhaust gas flowing to the second LNT and devices downstream thereof.

A method and system for reducing cycle to cycle variation of an engine is provided. The system may determine fuel injection characteristics and predict a gas burning rate or flame speed based on the fuel injection characteristics. The system may adjust an ignition timing in response to the predicted gas burning rate within the same engine cycle.

An exhaust purification system includes: an NOx reduction type catalyst, which is provided in an exhaust system; a temperature acquisition unit, which acquires a catalyst temperature of the NOx reduction type catalyst; and a regeneration treatment unit, which executes a catalyst regeneration to recover an NOx purification capacity, wherein the regeneration treatment unit alternately executes a rich control, in which an exhaust air fuel ratio is set to a rich state to raise a temperature of the NOx reduction type catalyst to a predetermined target temperature, and a lean control, in which the exhaust air fuel ratio is set to a lean state to lower the temperature of the NOx reduction type catalyst, and sets an execution period of the lean control based on a deviation between the catalyst temperature acquired by the temperature acquisition unit during the previous rich control and the target temperature.

A reciprocating engine system includes a cylinder, a piston disposed within the cylinder, a knock sensor disposed proximate to the cylinder and configured to detect vibrations of the cylinder, piston, or both, a crankshaft sensor configured to sense a crank angle of a crankshaft, and a controller communicatively coupled to the knock sensor and the crankshaft sensor. The controller is configured to receive a raw knock signal from the knock sensor and a crank angle signal from the crankshaft sensor corresponding to vibrations of the cylinder, piston, or both relative to the crank angle of the crankshaft, convert the raw knock signal into a digital value signal, and at least one of a crank angle for a start of combustion, a peak firing pressure, a percentage of fuel mass fraction burn, or a combination thereof, based on the digital value signal and the crank angle.

An exhaust gas purification system for an internal combustion engine includes an oxidation catalyst device on an upstream side in an exhaust passage of an internal combustion engine and a lean NOx trap catalyst device on a downstream side, a controller which controls the exhaust gas purification system is configured to, when a temperature-rising control of an exhaust gas in a regeneration control is performed to recover a purification ability of the exhaust gas purification system, perform a control that changes a measurement position of a control temperature which is a control amount of a feedback control in the temperature-rising control, according to an excess air ratio or an oxygen concentration of the exhaust gas passing through the exhaust passage.

An engine control device is provided, which includes an oxidation catalyst provided in an exhaust passage to oxidize unburned fuel within exhaust gas, a NO.sub.x catalyst provided integrally with or downstream of the oxidation catalyst, a PM filter provided in the exhaust passage downstream of the oxidation catalyst to capture fine particulate matter within the exhaust gas, a fuel injector, and a controller. When the particulate matter is accumulated by a given amount, the controller starts a PM filter regeneration control to remove the particulate matter, and after this control is started and when the accumulation amount decreases by a given amount, the controller starts a NO.sub.x catalyst regeneration control to switch between a first state in which an air-fuel ratio of the exhaust gas is a stoichiometric air-fuel ratio or less and a second state in which the air-fuel ratio is higher than the stoichiometric air-fuel ratio.

An exhaust emission control device for an engine is provided with a first purifying catalyst including an HC adsorbent that adsorbs HC at a low temperature and releases HC at a high temperature and a diesel oxidation catalyst capable of oxidizing HC, a second purifying catalyst including a NOx catalyst capable of storing NOx contained in exhaust, a NOx catalyst regenerator that regenerates the NOx catalyst while raising the temperature of the NOx catalyst, and HC controller that decides whether the amount of adsorbed HC that is HC adsorbed by the HC adsorbent is equal to or more than a preset reference amount and, when the amount of adsorbed HC is decided to be equal to or more than the reference amount, raises the temperature of the first purifying catalyst.

An exhaust purification system includes: an NOx reduction type catalyst, which is provided in an exhaust passage; an intake air amount sensor, which detects an intake air amount of the internal combustion engine; and a controller, which executes a regeneration treatment that recovers an NOx purification capacity of the NOx reduction type catalyst by switching an exhaust air fuel ratio from a lean state to a rich state by using: an air-system control to reduce the intake air amount; and an injection-system control to increase a fuel injection amount, wherein, in response to a detection value of the intake air amount sensor, the controller changes at least one of a fuel injection timing and the fuel injection amount in the internal combustion engine, in at least one period of switching of: a period of starting the regeneration treatment; and a period of ending the regeneration treatment.

A reciprocating engine system includes a cylinder, a piston disposed within the cylinder, a knock sensor disposed proximate to the cylinder and configured to detect vibrations of the cylinder, piston, or both, a crankshaft sensor configured to sense a crank angle of a crankshaft, and a controller communicatively coupled to the knock sensor and the crankshaft sensor. The controller is configured to receive a raw knock signal from the knock sensor and a crank angle signal from the crankshaft sensor corresponding to vibrations of the cylinder, piston, or both relative to the crank angle of the crankshaft, convert the raw knock signal into a digital value signal, and at least one of a crank angle for a start of combustion, a peak firing pressure, a percentage of fuel mass fraction burn, or a combination thereof, based on the digital value signal and the crank angle.