Abstract: It is an object of the present invention to provide a fuel property detection apparatus that excels in durability and reliability and is capable of accurately detecting the biofuel concentration in a mixture of hydrocarbon fuel and biofuel with a compact and simple configuration. A fuel property sensor 22 includes a light-emitting device 28 and a light-receiving device 32, which detect the optical transmittance of a fuel in a fuel path 26; and a light-emitting device 36 and a position sensitive device 38, which detect the refractive index of the fuel. As the optical transmittance correlates with the RME concentration of the fuel, the RME concentration can be calculated from the detected optical transmittance. As the refractive index correlates with the cetane number of the fuel, the cetane number can be calculated from the detected refractive index. The optical transmittance is detected through the use of light within a wavelength range of 640 nm to 680 nm.

Abstract: A fuel property sensor is provided with three bypass passages and a measure passage. The measure passage is located inside of a closed loop which is comprised of common tangential lines of adjacent bypass passages and a part of profile line of each bypass passage in a cross section perpendicular to the measure passage. Even if the fuel property sensor is rotated around the axis of a fuel pipe in assembling the fuel property sensor to the fuel pipe, at least one of two bypass passages is always located above the measure passage in a vertical direction. Hence, bubbles included in the fuel are restricted from flowing into the measure passage. The fuel property sensor can detect the concentration of ethanol contained in the fuel with high accuracy.

Abstract: It is an object of the present invention to provide a fuel property detection apparatus that excels in durability and reliability and is capable of accurately detecting the biofuel concentration in a mixture of hydrocarbon fuel and biofuel with a compact and simple configuration. A fuel property sensor 22 includes a light-emitting device 28 and a light-receiving device 32, which detect the optical transmittance of a fuel in a fuel path 26; and a light-emitting device 36 and a position sensitive device 38, which detect the refractive index of the fuel. As the optical transmittance correlates with the RME concentration of the fuel, the RME concentration can be calculated from the detected optical transmittance. As the refractive index correlates with the cetane number of the fuel, the cetane number can be calculated from the detected refractive index. The optical transmittance is detected through the use of light within a wavelength range of 640 nm to 680 nm.

Abstract: A fuel property sensor is provided with three bypass passages and a measure passage. The measure passage is located inside of a closed loop which is comprised of common tangential lines of adjacent bypass passages and a part of profile line of each bypass passage in a cross section perpendicular to the measure passage. Even if the fuel property sensor is rotated around the axis of a fuel pipe in assembling the fuel property sensor to the fuel pipe, at least one of two bypass passages is always located above the measure passage in a vertical direction. Hence, bubbles included in the fuel are restricted from flowing into the measure passage. The fuel property sensor can detect the concentration of ethanol contained in the fuel with high accuracy.

Abstract: In a detection of an alcohol concentration, a first light and a second light are irradiated to a mixed liquid including a fossil fuel, an alcohol, and water, and the alcohol concentration is calculated based on amounts of the first light and the second light permeated through the mixed liquid. In the detection, a difference of a transmittance of the fossil fuel with respect to the first light and each transmittance of the alcohol and water with respect to the first light is larger than a first value. In addition, a difference of a transmittance of water with respect to the second light and each transmittance of the fossil fuel and the alcohol with respect to the second light is larger than a second value.

Abstract: A device for purifying the exhaust gas of an internal combustion engine is disclosed. The device includes a particulate filter arranged in the exhaust system, which carries a catalyst for absorbing and reducing NOx. The catalyst absorbs NOx when the air-fuel ratio in the surrounding atmosphere thereof is lean and releases the absorbed NOx to purify NOx by reduction when the air-fuel ratio is stoichiometric or rich. The device further includes a catalytic apparatus for purifying NOx arranged in the exhaust system upstream of the particulate filter, which has an oxidation function.

Abstract: A device for purifying the exhaust gas of an internal combustion engine is disclosed. The device includes a particulate filter arranged in the exhaust system, which carries a catalyst for absorbing and reducing NOx. The catalyst absorbs NOx when the air-fuel ratio in the surrounding atmosphere thereof is lean and releases the absorbed NOx to purify NOx by reduction when the air-fuel ratio is stoichiometric or rich. The device further includes a catalytic apparatus for purifying NOx arranged in the exhaust system upstream of the particulate filter, which has an oxidation function.

Abstract: A NOx catalyst in the exhaust passage of an internal combustion engine is capable of lean burn and adapted to release and reduce absorbed NOx by a reducing agent. Reducing agent supplier is provided in the exhaust passage on the upstream side of the NOx catalyst. A load detector detects the load of an internal combustion engine. Reducing agent addition controller controls the reducing agent addition period and the reducing agent addition interval based on the load of the internal combustion engine, whereby sufficient reducing agent is supplied to the NOx catalyst side independently of the operating condition.

Abstract: The present invention is provided with an NOx catalyst 17 provided in the exhaust passage of an internal combustion engine capable of lean burn and adapted to release and reduce absorbed NOx by a reducing agent, a reducing agent supplying means 19 provided in the exhaust passage on the upstream side of the NOx catalyst 17, a load detecting means for detecting the load of an internal combustion engine 1, and a reducing agent addition control means for controlling the reducing agent addition period and the reducing agent addition interval on the basis of the load of the internal combustion engine 1. The addition period and the addition interval for the reducing agent are controlled taking into account, for example, the degree to which reducing agent adheres to the wall surface in the exhaust passage depending on the velocity, temperature, etc.

Abstract: A device for purifying the exhaust gas of an internal combustion engine is disclosed. The device comprises a particulate filter arranged in the exhaust system, which carry a catalyst for absorbing and reducing NOx. The catalyst absorbs NOx when the air-fuel ratio in the surrounding atmosphere thereof is lean and releases the absorbed NOx to purify NOx by reduction when the air-fuel ratio is the stoichiometric or rich. The device further comprises a catalytic apparatus for purifying NOx arranged in the exhaust system upstream of the particulate filter, which has an oxidation function.