03-173660-01
5. TRANSAXLE ELECTRONIC CONTROL SYSTEM
1) General Information
The transmission control unit (TCU) and its input/output network control the following transmission
operations:
Shift timing
Line pressure
Clutch pressure (shift feel)
Torque converter clutch -
-
-
-
also uses these signals when determining transaxle operating strategy. Using all of these input signals,
the TCU can determine when the time and conditions are right for a shift, or when to apply or release the
torque converter clutch. It will also determine the pressure needed to optimise shift feel.
2) TCU (Transmission Control Unit)
The transaxle control unit (TCU) is mounted
under the driver's seat and controls the operation
of the transaxle.
Internal sensors and signals received across the
CAN bus in analogue and digital forms such as:
Transaxle input speed
Transaxle output speed
Accelerator pedal position
Gear selector position
Engine torque
Engine speed
Transaxle fluid temperature
Brake pedal status
Engine oil temperature
Engine coolant temperature
Ambient air temperature
Barometric pressure -
-
-
-
-
-
-
-
-
-
-
-
The TCU monitors all TCU inputs and outputs to confirm correct system operation. If a fault occurs the
TCU is able to perform default action and inform the driver of the problem through the instrument cluster
warning lights. Detailed information is available via trouble codes which can be read with the service tool.
04-90000-00
3. DUAL MASS FLYWHEEL (DMF)
The dual mass flywheel (DMF) is of having a mass divided into two halves.
While one mass is connected to the engine crankshaft, which is affected by the mass moment of inertia
of the engine, the other mass is affected by one of the transmission.
The divided dual masses are connected to the coil spring and damping system internally.
The DMF has the following benefits: ▶
Reducing fuel consumption by lowering engine speed
Reducing rattling noise and vehicle vibration in all driving ranges
Reducing synchronization wear
Facilitating gear change
Protecting power train parts by preventing excessive load from being delivered -
-
-
-
-
Primary flywheel
Secondary flywheel
Arc damper spring
Torque limiter
Ring gear 1.
2.
3.
4.
5.
12-8
Installation of steering
gear box and pipeInstallation of pipe
Installation of reservoir and hoseInstallation of power steering pump
and pipe
2. SYSTEM LAYOUT
The steering pump is driven by the engine power through a belt. This pump circulates the power steering
oil from the reservoir -> steering pump -> oil supply pipe -> steering gear box -> oil return pipe ->
reservoir to perform steering operations.
Return pipe
Supply pipe
13-6
Hydraulic power steering Electric power steering
1. OVERVIEW
The electric power steering, EPS, does not have any belt-driven steering pump constantly running, so it
is lightweight and the motor consumes energy only when the steering wheel is turned by the driver, and
this leads to improvement in fuel efficiency. Also, the elimination of a belt-driven pump and its
accessories greatly simplifies manufacturing and maintenance. While offering these benefits, as it does
not contain any steering oil, the environment is not polluted both when the steering system is produced
and discarded.
In other words, the electric power steering (EPS) system uses the electric motor to assist the steering
force. It functions independently regardless of whether the engine is running or not, unlike the existing
hydraulic power steering.
The EPS system generates an assist steering force variably depending on the driving conditions by
controlling the motor's operation, based on the input signals from the sensors such as torque sensor and
angle sensor. In turn, the EPS receives the torque signal by the driver's movements of the steering
wheel, as well as the vehicle speed, and uses the motor to determine the assist torque. The EPS
controls the motor for this. Another features of EPS are fail-safe function, diagnosis function,
communication function between units and interface function for external diagnostic device.
The EPS system components such as the torque sensor, steering angle sensor, fail-safe relay, etc. are
located in the steering column and EPS unit assembly.
Advantages: ▶
Assurance of improved steering
Provides optimal steering force according to the
vehicle speed
Enhanced steering stability while driving at high
speed (1)
-
-Reduced fuel consumption
Consumes energy only when steering wheel
is turned (improved by 3 to 5%)
Energy saving (reduced by 85% compared
with hydraulic power steering)
Reduced number of parts: Elimination of
steering pump, hydraulic hose, pump pulley,
oil reservoir, belt, bracket, etc. (2)
-
-
-
Comparison between hydraulic power steering and electric power steering (EPS) ▶
