Circuito de refrigeração motores M52TU e M54

Área de discussão geral

Moderador: Staff

Responder
Avatar do Utilizador
navigator
Membro Gold
Mensagens: 1445
Registado: 09 set 2009, 10:25
O meu Carro:: 328ci E46

Circuito de refrigeração motores M52TU e M54

Mensagem por navigator »

Decidi partilhar esta informação na sequência de um tópico em que se compara funcionamentos de termostátos. O M52TU tem um sistema de refrigeração completamente novo, relativamente ao M52. A circulação de água faz-se primeiro na cabeça do motor para a manter mais fresca e ganhar eficiência volumétrica. Depois pelo bloco para o manter mais quente e baixar atritos de funcionamento. O termostato usa um núcleo de cera que expande com a temperatura e fecha circuito com a ajuda de uma resistência eléctrica.

O texto original é este:
Electrically Heated Thermostat
Model specific variants of the electrically heated thermostat are now equipped on all LEV/
ULEV compliant engines. This thermostat allows the engine to run hotter than conventional
thermostats improving fuel economy.
The ECM also electrically activates the thermostat to lower the engine coolant temperatures
based on monitored conditions. It is both a conventionally functioning and ECM controlled
thermostat (two stage operation). ECM control adds heat to the wax core causing the thermostat
to open earlier than it’s mechanical temperature rating providing increased coolant
flow.

Conventional Function: The thermostat begins to open at 103ºC. This is at the inlet side of the water pump and represents the temperature of the coolant entering the engine. Before the 103ºC temperature is realized, the coolant is circulated through the engine block by the water pump.

After the temperature reaches 103ºC it is maintained as the inlet temperature by the thermostat. The coolant temperature at the water pump engine outlet is approximately 110ºC. The additional 7ºC is achieved after the coolant has circulated through the block.

The operating temperature of the engine will remain within this range as long as the engine is running at part load conditions and the engine coolant temperature does not exceed 113ºC.

ECM Control
Electric thermostat activation is based on the following parameters:
• Engine temperature > 113ºC
• Radiator Coolant Outlet Temperature
• Load signal “ti” > 5.8 ms
• Intake air temp > 52ºC
• Vehicle speed > 110 MPH

When one or more of these monitored conditions is determined, the ECM activates
(switched ground) the thermostat circuit. The activated heating element causes the wax
core in the thermostat to heat up and open the thermostat increasing coolant circulation
through the radiator which brings the engine temperature down.
The temperature of the coolant at the inlet side of the water pump will drop to approximately
85ºC and the temperature at the outlet side will drop to approximately 103ºC when activated.
Imagem
Imagem

Avatar do Utilizador
navigator
Membro Gold
Mensagens: 1445
Registado: 09 set 2009, 10:25
O meu Carro:: 328ci E46

Re: Circuito de refrigeração motores M52TU e M54

Mensagem por navigator »

Electric Fan
The electric cooling fan is controlled by the ECM. The ECM uses a remote power output
final stage (mounted on the fan housing). The power output stage receives power from a
50 amp fuse (E46 - located in glove box above the fuse bracket). The electric fan is controlled
by a pulse width modulated signal from the ECM.

The fan is activated based on the ECM calculation (sensing ratio) of:
• Coolant outlet temperature
• Calculated (by the ECM) catalyst temperature
• Vehicle speed
• Battery voltage
• Air Conditioning pressure (calculated by IHKA
and sent via the K-Bus to the ECM)

After the initial test has been performed, the fan is brought up to the specified operating
speed. At 10% (sensing ratio) the fan runs at 1/3 speed. At a sensing ratio of between 90-
95% the fan is running at maximum speed. Below 10% or above 95% the fan is stationary.
The sensing ratio is suppressed by a hysteresis function, this prevents speed fluctuation.

When the A/C is switched on, the electric fan is not immediately activated.

Torque Interfaces

If torque reduction or increase is required for ASC/DSC/MSR/AGS, the ECM will regulate
engine power in the following manner:
• If less torque is required, the ignition timing is
reduced (fast intervention), the idle speed actuator
and MDK/EDK reduce intake air.
• If increased torque is required (MSR), the idle
speed actuator and MDK increase intake air.

The data required for engine torque manipulation
is relayed via the CAN bus.
Imagem

Responder

Voltar para “Discussão Geral”