Crankcase emission control system - ’L’Series

Crankcase emission control system - ’L’Series

A positive crankcase ventilation system is used to vent crankcase gases to the air induction system. Gases from the crankcase are drawn into the inlet manifold to be burnt in the combustion chambers with the fresh air/fuel mixture. The system provides effective emission control while the engine is running under all circumstances.

Crankcase gases are drawn from the camshaft cover into the turbocharger intake via a depression limiting valve (crankcase pressure limiting valve). The valve closes progressively as engine speed increases, so limiting the maximum depression in the crankcase.

NOTE: Injection timing is extremely important with regards the effects on emissions. The 2.0 L-series engine injection timing is electronically controlled (Refer to the Engine Management - EDC section ).

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NOTE: The Freelander 2.0 L-series engine incorporates an intercooled turbo-charger. Cooling the intake air increases the density of the oxygen mass per unit volume that is available for combustion, and so improves the engine combustion performance. In addition, the lower combustion temperature helps to inhibit the formation of oxides of Nitrogen (NO_x).

CAUTION: The depression limiting valve taking crankcase fumes to the intake of the turbo-charger must be fitted in the correct orientation.

Exhaust emission control - ’K’ Series

The engine management system provides accurately metered quantities of fuel to the combustion chambers to ensure the most efficient air to fuel ratio under all conditions of operation. A further improvement to combustion is made by measuring the oxygen content of the exhaust gases to enable the quantity of fuel injected to be varied, maintaining the optimal ratio necessary for efficient gas conversion by the catalytic converter.

The correct operation of the catalytic converter is dependent upon closed-loop control of the oxygen concentration in the exhaust gas entering the converter. The quantity of oxygen in the exhaust gas is determined by a heated oxygen sensor situated in the exhaust front pipe. The heated oxygen sensor provides the Engine Control Module (ECM) with a signal proportional to the oxygen content. The ECM can then determine whether any adjustment is required to the amount of fuel being injected to achieve the correct exhaust gas content, and implement the required changes.