sensor introduce

Oxygen sensors are essential components in engines that use three-way catalytic converters to reduce exhaust pollution. Once the air-fuel ratio of the mixture deviates from the theoretical air-fuel ratio, the three-way catalyst affects CO The purification ability of HC and NOx will sharply decrease. Therefore, an oxygen sensor is installed in the exhaust pipe to detect the concentration of oxygen in the exhaust and send a feedback signal to the ECU. The ECU then controls the increase or decrease of the fuel injection amount of the fuel injector, thereby controlling the air-fuel ratio of the mixture near the theoretical value. In order to achieve high exhaust purification rate and reduce carbon monoxide (CO) in the exhaust, an electronic fuel injection vehicle is equipped The composition of (HC) hydrocarbons and (NOx) nitrogen oxides requires the use of a three-way catalytic converter. However, in order to effectively use a three-way catalytic converter, it is necessary to precisely control the air-fuel ratio so that it always approaches the theoretical air-fuel ratio. The catalytic converter is usually installed between the exhaust manifold and the muffler. Oxygen sensors have a characteristic, It outputs a sudden change in voltage near the theoretical air-fuel ratio (14.7:1). This characteristic is used to detect the concentration of oxygen in the exhaust and feedback it to the computer to control the air-fuel ratio. When the actual air-fuel ratio increases, the concentration of oxygen in the exhaust increases, and the oxygen sensor notifies the ECU of the lean state of the mixture (small electromotive force: 0V). When the air-fuel ratio is lower than the theoretical air-fuel ratio, the concentration of oxygen in the exhaust decreases, The status of the oxygen sensor (high electromotive force: 1 volt) notifies the (ECU) computer The ECU determines whether the air-fuel ratio is low or high based on the difference in electromotive force from the oxygen sensor, and correspondingly controls the duration of fuel injection. However, if there is a malfunction in the oxygen sensor that causes the output electromotive force to be abnormal, The (ECU) computer cannot precisely control the air-fuel ratio. Therefore, the oxygen sensor can also compensate for the error in the air-fuel ratio caused by wear and tear of mechanical and other components of the electronic fuel injection system. It can be said that it is the only "intelligent" sensor in the electronic fuel injection system. The function of the sensor is to determine whether there is excess oxygen in the exhaust after engine combustion, that is, the oxygen content, and convert the oxygen content into a voltage signal to transmit to the engine computer, Enable the engine to achieve closed-loop control with the goal of excessive air factor; Ensure that the three-way catalytic converter has the maximum conversion efficiency for hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOX) in the exhaust, and maximize the conversion and purification of emitted pollutants)

Installation position of oxygen sensor

The installation position of the oxygen sensor is in the exhaust pipe. Generally, the first one is installed before the three-way catalytic converter, and the second one is installed after the three-way catalytic converter. One is a sensor for detecting the combustion situation of the engine, and the other is an oxygen sensor for detecting the three-way catalytic converter. The oxygen sensor is seen to have a screw with a wire on the back of the exhaust pipe. Both oxygen sensors work normally at the same time, transmitting the collected information to the ECU and adjusting and controlling the fuel injection quantity from time to time, Ensure the normal operation of the engine. If the oxygen sensor is damaged, during driving, especially within 40 to 60 miles, the engine can be felt to shake during rapid acceleration. The degree of shaking may vary depending on the vehicle model. Note: The thread size of the oxygen sensor for automobiles is generally M18, and it is recommended to install it with a torque of 45 to 55 Nm. In addition, the exhaust pipe and oxygen sensor threads should be carefully removed, Don't be damaged. It can easily handle high temperature environments. When the oxygen sensor works, the temperature can reach 800 ℃. To prevent the oxygen sensor threads from sintering in high temperature environments, anti jamming agents need to be applied. In addition, the exhaust pipes and oxygen sensors of the vehicle are very hot after driving. To prevent burns, it is necessary to wait for the exhaust pipes to completely cool before proceeding to the next step of operation

Fiat CROMA introduce

The new Croma station wagon has a more dynamic and modern exterior design, although only modified from the current model, the effect is indeed immediate. The new car incorporates the design elements of the new generation Fiat, and we can see the shadow of the new Punto and Brava. The engine hood of the new car has clear lines and a strong sense of power. The elongated front headlights are very dynamic, and the horizontal grille has been replaced by a chrome plated mesh. The tail light shade is darker and cooler than the old model, and the new design of the rear bumper is more dynamic. The cabin of the new car has also been decorated, full of Italian style luxury. The seats are made of leather and fabric. The newly designed instrument panel and steering wheel are very elegant. The standard configuration of the new Croma is already very rich, including rain sensors, reverse radar, tire pressure sensors, cruise control system, ABS anti lock braking system, EBD brake force distribution system, ESP body stability control system, front dual airbags, side airbags, air curtains, and knee airbags. In addition, the new car also has a large number of optional configurations, Including DVD audio and video system, navigation and information system with Bluetooth function, high fidelity audio system, etc. The second row seats can be fully folded, and when the passenger seat is folded down, it becomes a small coffee table. The cargo space can be conveniently increased from 500 liters to 1610 liters. Fiat provides five engines for users to choose from for the new Croma, including two gasoline engines and three Multijet turbocharged diesel engines. The entry-level power is a 1.8-liter gasoline engine with a 140 hp output, and the top-level power configuration is a 2.4-liter turbocharged diesel engine with a 200 hp output. The diesel engine comes standard with a six speed automatic transmission, while the gasoline engine comes standard with a five speed manual transmission. 2.2 A gasoline engine can be equipped with a six speed automatic transmission, while a 1.9-liter diesel engine can be equipped with a five speed manual transmission (Kevin Lee)