Engine: Description and Operation
Engine generalB5244S6 and B5244S, USA
General
B5244S6, Super Ultra Low Emission Vehicle (SULEV+), California
- The B5244S6 is based on the B5244S
- Corresponds to emissions regulations Partial Zero Emission Vehicle (PZEV). This car must satisfy statutory warranty, exhaust and EVAP regulations
- Introduced only in the S60 and V70
- Due to emissions requirement, only available in California
- Maximum torque 225 Nm. Maximum power 123 kW
- DENSO engine management system
- New Electronic Throttle Actuator (ETA)
- Start is based on the Wide Range concept
- Only available with automatic transmission AW 55-50 SN
- The final drive ration is 2.65:1 to ensure good response.
B5244S
- Only available in the 125 kW version
- DENSO engine management system
- New Electronic Throttle Actuator (ETA)
- Start is based on the Wide Range concert
- Start is based on the Wide Range concept
- Available with both manual and automatic transmissions
- Final drive 2.44:1.
B5244S6, news
Cylinder head
Cylinder head with Continuous Variable Valve Timing (CVVT) for both the intake and exhaust camshafts.
Change over angle CVVT:
- intake = 60 crankshaft degrees
- exhaust = 30 crankshaft degrees.
Wide Range. When cold starting in positions P/N (automatic transmissions) or neutral (manual transmissions), the engine speed may initially reach approx. 2000 rpm before dropping immediately to approx. 1650 rpm for 15 - 20 seconds. The engine then runs at a low ignition setting and lean lambda.
The engine speed (RPM) then drops to idle speed approx. 750 rpm. This is to reduce the emissions during the warm-up phase.
The camshaft toothed belt is reinforced to increase service life. The belt tensioner has a new gasket to ensure an optimal seal.
Pistons
Graphite coated pistons.
The pistons have a two piece oil control ring. The design of a stainless steel ring with nitrated steel spring ensures good service life. The thickness of the oil control ring is 2 mm.
Evaporative emission canister (EVAP canister) in the Air Cleaner (ACL) housing
An EVAP canister is integrated in the Air Cleaner (ACL) housing.
There is no service interval for the EVAP canister. If the canister is damaged and needs to be replaced, the entire cover must be replaced. The canister absorbs the hydro-carbons which return through the air cleaner when the engine is switched off. When the engine is started, the absorbed hydro-carbons enter into the air flow and are combusted.
Crankcase ventilation
The connection nipple for the crankcase ventilation at the intake manifold has been modified to provide more even distribution of the crankcase vapors between the cylinders. A Positive Temperature Coefficient (PTC) element prevents freezing. The flame trap has a labyrinth which efficiently separates oil from the crankcase vapors before they are returned to the intake manifold.
Resonator
There is a resonator on the hose between the Mass Air Flow (MAF) sensor and the Electronic Throttle Actuator (ETA). This is to satisfy European legal requirements for vehicle sound levels. By modifying the unfavorable frequencies which occur at high engine speeds, the sound levels of the intake and exhaust systems are reduced.
When the pulses affect the measurement function of the Mass Air Flow (MAF) sensor, software in the Engine Control Module (ECM) compensates for this. Because the pulses have been reduced, the software has also been modified from previous Engine Control Module (ECM). If the resonator is removed, the signals from the Mass Air Flow (MAF) sensor will be incorrectly interpreted by the Engine Control Module (ECM).
Electrical cooling fan for the control module box
The fan starts when the temperature in the control module box reaches approx. +70°C and stops at approx. +65°C. The temperature sensor in the Engine Control Module (ECM) is used as a reference.
Three-Way Catalytic Converter (TWC)
The manifold with the catalytic converter, Closed Coupled Catalyst (CCC), has double ceramic monoliths. The Under Floor Catalyst (UCF) has a ceramic monolith.
B5244S, ULEV (Ultra Low Emission Vehicle)
Differences from B5244S6:
- Continuous Variable Valve Timing (CVVT) only for the intake camshaft. Change over angle CVVT intake = 60 crankshaft degrees
- Emissions regulations apply for 100,000 miles/10 years
- The pistons have three piece oil control rings, 2.5 mm thick
- A new manifold gives improved torque at low engine speeds
- No EVAP canister in the Air Cleaner (ACL) housing
- Only an under floor catalyst with two ceramic monoliths and integrated muffler.
When compression testing
- Disconnect engine speed (RPM) sensor before carrying out a compression test.
- The Diagnostic Trouble Code (DTC) must be erased when the engine speed (RPM) sensor has been reconnected.
B5254T2
General
- Based on the B5244T3
- There have been a number of changes to the engine, resulting in improved performance and lower emissions
- A modified length of stroke results in a cylinder capacity of 2521 cm3.
- Meets the emissions requirements for EURO 2005 (EURO 4) and ULEV II
- The maximum torque of 320 Nm is reached at 1500 rpm
- Maximum power is 154 kW (210 hk) at 4800 rpm
- Engine management system Bosch ME 7.01
- The start sequence is based on the Wide Range concept.
General, continued
Crankshaft, crankshaft bearing
Stroke of 93.2 mm. Forged. Weight: 21559 grams. Connecting rod pins: [diameter] 50.00 mm. Main bearing journals: [diameter] 65.00 mm. Both the upper and lower crankshaft bearings are aluminum. The upper bearing has a lubrication hole.
Connecting rods, connecting rod bearing
Forged connecting rods with split covers. Length center to center = 145 mm. Weight = 634 grams. Both the upper and lower bearings are aluminum.
Pistons
Graphite coated pistons. Diameter/length gudgeon pin = 21 mm/60 mm.
Cylinder head, camshafts
Cylinder head with Continuous Variable Valve Timing (CVVT) for both the intake and exhaust camshaft. Change over angle CVVT:
- intake = 50 crankshaft degrees
- exhaust = 30 crankshaft degrees.
Other
Flame trap with labyrinth. Modified manifold providing improved gas flow and more exhaust energy to the turbine in the Turbocharger (TC). Gives a quicker turbocharger response.
The camshaft toothed belt is reinforced to increase service life. The belt tensioner has a new gasket to ensure an optimal seal.
Engines, General modifications
5 and 6 cylinder diesel and gasoline engines
Generator
The first ramp up of the charge current (after start) is always completed, irrespective of the engine speed (rpm). This increases the engine load successively, preventing sudden loads. Otherwise the ramp up characteristic of the charge current is maintained.
Previously the ramp up was interrupted and full charge current was permitted when the generator speed exceeded approx. 3400 rpm, even during the first ramp up.
Function:
- The charge current is 0 A until the generator speed has reached approx. 1450 rpm. The charge regulator continues to maintain the charge current at 0 A for a few further seconds
- Ramp up then begins. For a number of seconds the charge current increases linearly from 0 % to 100 % of the maximum power handling capacity. If the requirement is less than the power handling capacity, it takes less than 6 seconds to reach the controlled condition.
General:
- All 5 cylinder engines have generators with freewheels
- 6 cylinder engines have fixed pulleys
- All 5 and 6 cylinder engines have 140 A generators.
Unique to the XC90:
- The 5 cylinder engines (diesel and gasoline) with rear air conditioning have 160 A generators
- The 6 cylinder engines have 160 A generators.
5 and 6 cylinder gasoline engines
Pistons
All engines (except B5204TX, B5234TX and B5244TX) have pistons with the mantles coated with graphite. This reduces noise and lowers the friction between the piston and the cylinder, particularly when cold starting and under large loads at low engine speeds. Also improves resistance to scoring.
Pulsation damper fuel rail
The engines have a pulsation damper, Air Tube Damper (ATD), in the fuel rail. The pulsation damper is filled with air and helium. Helium is used during manufacture to check for leaks.
Combined temperature/pressure sensor for intake air (turbocharged engines only)
The temperature/pressure sensor, T-MAP (Temperature/Manifold Absolute Pressure), is on the outlet side of the Charge Air Cooler (CAC). The sensors work according to the previous principles.
There are new resistance values for the temperature sensor.
5 cylinder naturally aspirated and turbocharged engines
The flame trap has a labyrinth which efficiently separates oil from the crankcase vapors before they are returned to the intake manifold. Does not apply to Bi-Fuel cars.
The camshaft toothed belt is reinforced to increase service life. The belt tensioner has a new gasket to ensure an optimal seal.
B6294T and B6294S2
The diameter of the gear drive on the coolant pump has been reduced. The number of teeth has been reduced from 21 to 17. The pump operates at a higher speed, improving the flow and therefore engine cooling. New tension pulley for the camshaft. The increased diameter compensates for the smaller gear drive for the coolant pump. The timing belt is unchanged.
B5244S/S2
- CVVT (Continuous Variable Valve Timing) only for the intake camshaft. Change over angle CVVT intake = 60 crankshaft degrees
- A new manifold gives improved torque at low engine speeds
- Only an under floor catalyst with two ceramic monoliths and integrated muffler
- New Electronic Throttle Actuator (ETA)
- Start is based on the Wide Range concept
- Electrical cooling fan for the control module box. The fan starts when the temperature reaches
- approx. +70°C and stops at approx. +65°C. The temperature sensor in the Engine Control Module (ECM) is used as a reference
- The connection nipple for the crankcase ventilation at the intake manifold has been modified to provide more even distribution of the crankcase vapors between the cylinders. A Positive Temperature Coefficient (PTC) element prevents freezing.
Resonator
There is a resonator on the hose between the Mass Air Flow (MAF) sensor and the ETA (Electronic Throttle Actuator). This is to satisfy European legal requirements for vehicle sound levels. By modifying the unfavorable frequencies which occur at high engine speeds, the sound levels of the intake and exhaust systems are reduced.
When the pulses affect the measurement function of the Mass Air Flow (MAF) sensor, software in the Engine Control Module (ECM) compensates for this. Because the pulses have been reduced, the software has also been modified from previous Engine Control Module (ECM). If the resonator is removed, the signals from the Mass Air Flow (MAF) sensor will be incorrectly interpreted by the Engine Control Module (ECM).