Part 1

Engine general

B5244S6 and B5244S, USA

General




B5244S6, SULEV+ (Super Ultra Low Emission Vehicle), California
- The B5244S6 is based on the B5244S
- Corresponds to emissions regulations PZEV (Partial Zero Emission Vehicle). 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 ETA (Electronic Throttle Actuator)
- Start is based on the Wide Range concept
- Only available with automatic transmission AW 55-50SN
- 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 ETA (Electronic Throttle Actuator)
- 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 CVVT (Continuous Variable Valve Timing) 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 approximately2000 rpm before dropping immediately to approximately1650 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 approximately750 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 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 modules (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 approximately +70 °C and stops at approximately +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, CCC (Closed Coupled Catalyst), has double ceramic monoliths.
The Under Floor Catalyst (UCF) has a ceramic monolith.

B5244S, ULEV (Ultra Low Emission Vehicle)
Differences from B5244S6:
- CVVT (Continuous Variable Valve Timing) 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.

B5244S6, fuel injection system





Combined fuel pressure / fuel temperature sensor
Fuel temperature sensor
A negative temperature coefficient (NTC) sensors transmits a voltage signal (corresponding to a certain temperature) to the engine control module (ECM). The signal is used to compensate for changes in fuel temperature. The injection period is regulated to provide compensation.
Example: If the engine is restarted after a short stop, the temperature of the fuel in the fuel rail will have increased. The engine control module (ECM) uses the signal from the sensor to compensate for the increased temperature by extending the injection period. (The volumetric energy content of hot fuel is lower than cold fuel).
Fuel pressure sensor
For information about this function, see "Control of the fuel pump".

Fuel injection system miscellaneous

- Fuel tank constructed from stainless steel
- Fuel pump (FP) which is activated as required
- Leak diagnostic based on the overpressure principle
- DENSO fuel control system
- New DENSO ETA (Electronic Throttle Actuator).

Fuel supply system B5244S6 and B5244S, USA

Fuel tank




1. Fuel filler pipe
2. EVAP canisters
3. FLVV (Float Limit Vent Valve)
4. Outlet to canisters
5. Roll over valves
6. Control module for the fuel pump (FP) (Pump Electronic Module)
7. Wiring
8. Fuel pump
9. Service hatch
10. Water separator, LSD (Liquid Separation Device).
- In order to satisfy statutory requirements in California, the fuel tank is made of stainless steel. The release of hydro-carbons is reduced because steel is less permeable than plastic
- Volume 70 liters
- The fuel filler pipe, which is manufactured from stainless steel, is welded to the fuel tank. The small diameter of the pipe limits the flow of air into the fuel tank when refueling. The air supply effects the degree to which the canisters full up and therefore emissions
- Fuel tank filler cap with more efficient valves
- The geometric shape of the fuel tank enables three roll-over valves to be used
- The service hatch is made of plastic. The hatch is secured using a stainless steel nut
- The B5244S6 engine has an evaporative emission (EVAP) system with two canisters. There is a water separator upstream of the canisters. The EVAP canister closest to the fuel tank has three chambers filled with active carbon. There is another canister, HCS (Hydro Carbon Scrubber), connected in series. Based on a honeycomb coated with active carbon
- B5244S has only one canister (does not have HCS).

Fuel pump




1. Pump with an integrated PRV safety valve (Pressure Relief Valve)
2. PVV (Pressure Ventilation Valve)
3. Fuel level sensor
4. Fuel filter
5. Non-return valve
6. Ejector pump.
A fuel pump (FP) with a flow which is adjusted to suit the requirements. By controlling the power consumption of the pump based on the fuel requirement of the engine, the following is achieved:
- long service life (all components in the system must last 150 000 miles/15 years)
- tailored power consumption.
A DC motor drives a pump which works on the turbine principle.
Pump flow is as follows at:
- full load approximately 90 liters per hour at 400 kPa (corresponding to 380 kPa at the fuel rail)
- idle speed approximately 1.2 to 2.0 liters per hour.
The power consumption varies from approximately 8 A at full capacity to approximately 2 A at idle speed.

Valves
PVV (Pressure Ventilation Valve)
The valve compensates for surges in pressure that occur when, for example, fuel injection ceases during engine braking. Allowing fuel to continually pass through the valve ensures rapid pressure compensation. Any excess fuel flows into the pump housing.
The pressure is limited to 400 kPa (corresponds to 380 kPa at the fuel rail).
When the engine is switched off, the valve maintains a residual pressure in the fuel injection system to prevent condensation.
Non-return valve
Releases fuel into the pump housing when the fuel tank is refilled having been almost empty. The valve is closed if the car tilts so that fuel remains in the pump housing.
PRV (Pressure Relief Valve)
Safety valve integrated in the fuel pump (FP). The valve opens between 550 kPa - 850 kPa.

Ejector
Continuously fills the pump housing with fuel. approximately 10-15 liters per hour always flows from the fuel pump (FP) through the ejector and back to the pump housing.

Fuel filter
The fuel filter is in the pump housing. Cannot be replaced.

Fuel pump control




The following components are included in the system which controls the fuel pump:
- Engine control module (ECM) with built-in atmospheric pressure sensor
- Fuel pressure sensor
- Control module for the fuel pump (FP) (Pump Electronic Module).
Function
A piezo-electric fuel pressure sensor transmits a voltage signal to the engine control module (ECM) about the actual pressure in the fuel rail.
The engine control module (ECM) compares the signal with the signal from the atmospheric pressure sensor in the engine control module (ECM). The fuel pressure is regulated so that the pressure in the fuel rail is always 380 kPa above the atmospheric pressure (i.e. the difference in pressure is 380 kPa).
Depending on factors such as engine speed and load, the engine control module (ECM) transmits a calculated pulse width modulated (PWM) signal to the control module for the fuel pump (FP). The control module for the fuel pump sends the signal on to the fuel pump at a higher frequency.
The PWM signal corresponds to a certain feed voltage to the pump. This in turn corresponds to a certain pump flow rate. By adapting the supply voltage, the load of the pump matches the fuel requirement.
If the engine is running at higher engine speeds (RPM) and under high load, the speed of the pump is higher (greater flow) than at small loads and low engine speed (RPM).
If the pressure briefly rises to 400 kPa, during acceleration for example, the fuel flow is compensated by reducing the injection period. For longer periods of time, such as a couple of seconds, the fuel pressure is lowered via the fuel pump to compensate.
A diagnostic trouble code (DTC) is stored If the pressure sensor detects that the pressure remains at the same value for a long time. The emissions warning lamp lights if the same fault persists or returns.
A diagnostic trouble code (DTC) is stored in the fuel pressure system if there is no signal from the pressure sensor or if it is implausible. The fuel pump (FP) is controlled using a PWM signal. The signal is calculated from the fuel flow - based on the injection periods and the desired pressure.

Emissions classifications




The illustration shows the relationship between the different emissions classifications.
- Tier 1 (the applicable obligatory requirements, both federal and in California)
- TLEV (Transitional Low Emission Vehicle)
- LEV (Low Emission Vehicle)
- ULEV (Ultra Low Emission Vehicle)
- LEV II (Low Emission Vehicle, stage 2)
- ULEV II (Ultra Low Emission Vehicle, stage 2)
- SULEV (Super Ultra Low Emission Vehicle)
- NOx g/mile (nitrous oxides)
- CO g/mile (carbon monoxide)
- NMOG g/mile (Non-Methane Organic Gases). These are the basis of smog. In principle NMOG are hydro-carbons
- "A" symbolizes the optimal target of the car when it leaves the factory.

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.