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Models with the 1.6 and 2.0 liter engines

All models Nissan Sunny, described in this manual may use gasoline containing no tetraethyl lead, as well as have a system to help minimize emissions.

On all models the system reducing crankcase emissions, as well as the following systems, depending on the model:

Models with the carburettor engine of 1.6 liters without a catalytic converter - emission control system when the engine is idling and the throttle damper.

Models with the carburettor engine of 1.6 liters with a catalytic converter - catalytic converter, exhaust gas recirculation control system for the release of fuel vapors from the fuel system, air intake system, emission control system when the engine is idling and the throttle damper .

Models with the 1.6-liter engine and multi-point fuel injection system - catalytic converter, exhaust gas recirculation and a system of control over the release of fuel vapors from the fuel system.

Models with engine capacity of 2.0 liters and a single-point fuel injection system without a catalytic converter - a system of neutralization of the exhaust heat and the damper throttle.

Models with engine capacity of 2.0 liters and a single-point fuel injection system with catalytic converter - catalytic converter, exhaust gas recirculation system, the system of control over the release of fuel vapors from the fuel system, the system of thermal neutralization of exhaust gases and the damper throttle.

Models with engine capacity of 2.0 liters and a multi-point fuel injection system without catalytic converter - no additional emission control systems have not been established.

Models of "Phase I" (produced before June 1993) with an engine capacity of 2.0 liters and a multi-point fuel injection system with catalytic converter - catalytic converter and system control over the release of fuel vapors from the fuel system.

Models of "Phase II" (manufactured after June 1993) with an engine capacity of 2.0 liters and a multi-point fuel injection system with catalytic converter - catalytic converter, the system of control over the release of fuel vapors from the fuel system and exhaust gas recirculation.

System of decrease in emissions of crankcase gases

To reduce the emission of unburned hydrocarbons from the engine crankcase to air motor hermetically closed and intruding into the crankcase gases and vapors engine oil is withdrawn from the crankcase through the valve into the intake port, where they then go into the engine and are burned in the subsequent cycles of the engine.

If the intake manifold negative pressure is very low, the gases will be tightened in a crankcase thereof. When the vacuum in the intake manifold is not so large, the gases will leave the crankcase under the influence of higher (relatively) the pressure in the crankcase; when the engine is worn, the increased pressure in the crankcase (due to increased breakthrough gas) will cause part of the gases flow into the intake manifold at any pressure in the reservoir.

Catalytic Converter

The sensor is sensitive to the oxygen content of the exhaust gas and sends signals to the electronic control unit with different voltages depending on its concentration. If the intake air / fuel mixture is too rich, the sensor sends a signal to a high voltage. Voltage decreases with increasing oxygen content in the fuel mixture. The maximum coefficient of exhaust gas catalytic converter is achieved when the composition is supported by the chemically correct fuel mixture / intake air for complete combustion of gasoline - 14.7 parts (by weight) of air to 1 part of fuel (stoichiometric ratio). At this ratio, the voltage signal of the sensor sharply changes and the electronic control unit adjusts the composition of the fuel mixture / intake air by changing the pulse width of the injector (s) (the time during which the injector is open). On later models, the sensor has a built-in heating element (controlled by the electronic control unit), which serves to quickly warm up the sensitive tip of the sensor to the normal operating temperature.

System control release of fuel vapor from fuel system

In order to minimize emissions of unburned hydrocarbons into the atmosphere, on models with catalytic converter installed control the release of fuel vapors from the fuel system. Cap fuel filler is hermetically closed and a carbon filter collects gasoline vapors generated in the fuel tank (models with fuel injection), or in the fuel tank and carburetor float chamber (models with carburetor engine) when the vehicle is stationary. Pairs remain in the carbon filter as long as they can not be let out into the intake port during engine operation.

On models with the carburettor engine controls operation of the system thermovacuum valve, which is mounted in the intake manifold; thermovacuum valve also controls the exhaust gas recirculation system. When the engine is cold, the valve closes thermovacuum intake vacuum to the vacuum diaphragm valve of the coal filter and the filter is closed. When the engine is warmed up to normal operating temperature (70 ?� C), the valve opens and thermovacuum underpressure present in the intake manifold influences on the diaphragm carbon filter. The diaphragm valve is opened and all the couples gathered in the carbon filter, tightened into the inlet, followed by combustion in the next cycle of the engine.

On models "Phase I" (produced before June 1993) with an engine capacity of 2.0 liters and a multi-point fuel injection system activated carbon filter is connected directly to the intake manifold and the operation of the system controls the restrictor valve on the vacuum valve membrane filter. When the engine is running, negative pressure present in the intake manifold acts on the diaphragm through the restriction valve. When the engine is idling the valve is closed, but with an increase in engine speed, increases the vacuum in the intake manifold. The restrictor valve increases underpressure behind the diaphragm, thereby controlling the opening of the diaphragm valve according to the engine speed. Valve open slightly at low engine speed, but is fully opened with increasing engine speed.

On all models with fuel injection operation of the system of control over the release of fuel vapors from the fuel system controlled by an electronic engine control unit via a solenoid valve; the same solenoid valve controls the exhaust gas recirculation. To the engine to operate correctly after a cold start, and / or in idling mode, and also to protect the catalytic converter when entering the engine too rich mixture, the solenoid valve does not open the electronic control unit, until the engine is warmed up or it is not It will be given load. Thereafter, the solenoid valve is opened so that the collected fuel vapor could enter the intake pipe.

EGR

This system reduces the amount of unburned hydrocarbons in the exhaust gases as they have not been put into the catalytic converter. To this end, some of the exhaust gas taken from the exhaust manifold and discharged back into the intake manifold through a pipe connecting them, after which they are again involved in the operation of the engine. The EGR valve is set to the other end of the connection tube, which is attached to the intake manifold.

On models with the carburettor engine controls operation of the system thermovacuum valve and pressure. Thermal vacuum valve also controls the operation of the control system for the release of fuel vapors from the fuel system. When the engine is cold, the valve stops the flow thermovacuum vacuum to the EGR valve, and it remains closed. When the engine is at normal operating temperature (70 ?� C), thermovacuum valve opens, allowing underpressure influence the EGR valve through the valve pressure. Backpressure valve sensitive to the pressure of the exhaust gases and, according to it, opens or closes the EGR valve. When the exhaust pressure is high, the backpressure valve is closed, allowing underpressure affect EGR valve, opening it. When the pressure of the exhaust gas falls, back pressure valve opens, stopping the supply of vacuum to the EGR valve, the valve closes.

On models with fuel injection, exhaust gas recirculation is controlled by an electronic control unit of engine work through a solenoid valve and back pressure valve; solenoid valve also controls the operation of the control system for the release of fuel vapor from the fuel system. When the engine is cold, the electronic control unit of engine work keeps the solenoid valve closed, stopping the flow of the dilution recirculation valve. When the engine is warmed up to normal operating temperatures, the electronic control unit opens the solenoid valve, allowing underpressure influence the EGR valve through the valve pressure. Backpressure valve sensitive to the pressure of the exhaust gases and, according to it, opens or closes the EGR valve. When the exhaust pressure is high, the backpressure valve is closed, allowing underpressure affect EGR valve, opening it. When the pressure of the exhaust gas falls, back pressure valve opens, stopping the supply of vacuum to the EGR valve, the valve closes.

System of thermal neutralization of exhaust gases

This system reduces the amount of unburned hydrocarbons in the exhaust gases, preventing them from excessive contact with the exhaust gases. This is achieved by supplying additional air into the intake manifold when the intake manifold vacuum is very high. The system comprises only one valve.

The valve system of thermal neutralization of exhaust gases is sensitive to the pressure in the intake manifold. If the intake manifold vacuum is formed too high (i.e. when the throttle is closed at a high engine speed), the valve opens and passes into the intake manifold portion of fresh filtered air from the air filter housing.

The air intake system to the exhaust manifold

The air intake system to the exhaust manifold reduces the amount of unburned hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas passing portion of the filtered air filter air directly into the exhaust manifold for a substantial portion of the molecules of unburned hydrocarbons and carbon dioxide may be oxidized in the exhaust manifold before reaching the catalytic converter. The system includes air supply valve and a solenoid valve controlled by electronic control of engine operation.

In order to operate properly on the engine after a cold start and / or idling, the solenoid valve does not open the electronic control unit until the engine warms up and it will be given to the load. When these two conditions occur, the solenoid valve is opened to a portion of fresh filtered air filter, the air could get into the exhaust manifold. Combustion air from the air filter, the difference between the pressure in the exhaust manifold and the air filter, there is no need to use an air pump for supplying air. Air supply valve passes air in one direction only, so the exhaust gases can not enter the air filter.

Emission control system when the engine is idling

The system minimize exhaust emissions at idle motor serves to fuel mixture does not become too rich at high engine temperatures. This is achieved by additional air inlet into the intake manifold at high engine temperatures. The system comprises only one valve, which is mounted on the casing of the air filter.

The valve system to minimize exhaust emissions at idle motor has a bimetallic spring, sensitive to temperature. At low temperatures, the engine valve is closed. When the temperature in the housing of the air filter increases, the bimetallic spring valve is deformed and the valve is gradually opened. This allows fresh, filtered air filter, air to get into the intake manifold, increasing the oxygen content of the fuel mixture.

Throttle damper

Throttle damper serves to reduce the content of unburnt hydrocarbons in the exhaust gases when switching off the motor or a sudden reduction in turnover. This is achieved by preventing abrupt closure of the throttle, for example, when the driver is at a high engine speed quickly releases the accelerator pedal. The damper throttle serves as a shock absorber and slowly closes the throttle in the latter stages. This reduces the amount of unburned hydrocarbons in the exhaust gases, preventing the formation of the intake manifold vacuum is too large, which would lead to the ingress end of the unburned fuel to the exhaust manifold.