ENGINE COMPONENT AND LOCATION 103 When the accelerator pedal is released (and the Volvo Engine Brake switch is ON), the solenoid opens allowing some oil to escape through a small port. Reduced spring pressure moves the piston, opens the passage to the rocker shaft and increases the oil pressure. The system opens the exhaust valve during induction and again immediately before TDC on the compression stroke. The engine slows because the extra volume under compression takes more power to compress, and escaping pressure in the combustion stroke reduces the power output. A switch on the instrument panel allows the driver to engage or disengage Volvo Engine Brake.
If the ABS system becomes active, it automatically disables Volvo Engine Brake.If the oil temperature goes below 55°C (131°F), Volvo Engine Brake cannot be activated. A warning lamp on the instrument panel flashes if the driver attempts to activate it under this condition. A port in the cylinder head allows access to the oil passageway. The plug can be removed and a gauge inserted for use during diagnostic procedures.
System Oil Pressure Engine Speed/RPM Temperature Pressure 600 90 – 110°C (195 – 230°F) >250 kPa (>36 psi) >1100 90 – 110°C (195 – 230°F) 300 – 550 kPa (44– 80 psi) >1100 Cold Engine 650 kPa (95 psi) Rocker Shaft Engine Brake Engine Speed/RPM Oil Pressure Active 900 — 2300 220 kPa (32 psi) Inactive — 80 — 120 kPa (12 — 17 psi)