2004 september 24

Start-Stop, STOPStayCOOL/STOPStayWARM and Clutch-by-Wire
Valeo’s solutions for driving in the city
Paris, France, September 24th, 2004 - Start-Stop, STOPStayCOOL/STOPStayWARM
and Clutch-by-Wire are three innovations designed by Valeo to increase the well-being of
drivers and passengers in the car. The “Start-Stop” starter-alternator, can be enhanced by the
addition of the STOPStayCOOL/STOPStayWARM air-conditioning system which maintains a
comfortable temperature inside the cabin even when the engine has been cut off. The electric
Clutch-by-Wire system improves driving comfort in the city center. Valeo has reinvented the
pleasure of city-center driving!
Driver and passenger well-being and comfort are among Valeo’s key objectives. City driving
conditions are among the most stressful, and these three technical innovations aim to relieve
this stress. The starter-alternator and its Start-Stop function is the first step: its ability to stop
and re-start the engine instantaneously, silently and with no action required on the part of the
driver, means that no fuel is consumed and no pollution created when the vehicle is at a red
light or in a traffic jam.
However, this causes the A/C compressor and water pump to stop operating. To ensure the
vehicle’s occupants continue to benefit from optimum air temperature, Valeo has designed the
“STOPStayCOOL/STOPStayWARM” system.
Air conditioning that functions without the engine
The cooling function is obtained through an A/C evaporator that stores cold energy.
This evaporator contains a material which accumulates cold energy while the engine is
running normally. When the engine is cut by the Start-Stop system, the A/C fan continues to
operate, directing air through the evaporator, which cools the air before releasing it into the
cabin.
During cold weather, the cabin is heated using an additional electric water pump which
continues to circulate water between the engine - which remains hot - and the heating
radiator, so there is no interruption to the heating of air entering the cabin.
The STOPStayCOOL/STOPStayWARM system allows drivers to optimise the time the motor
is stopped and the fuel consumption reduction.
An electronic system that transforms the mechanical clutch
Repetitive use of the clutch pedal is one of the more uncomfortable aspects of city-center
driving. By replacing the effort of the driver, Valeo’s Clutch-by-Wire system offers vastly
improved driving comfort. The clutch pedal features a position sensor linked to an electronic
control unit (ECU). This unit controls the clutch actuator and operates the clutch directly.
This system allows the driver to choose whether or not to use the clutch-pedal. The gear
change can be carried out using the sensor on the gear stick. If the pedal is used, the system
is designed to reduce the effort of operating the pedal, while retaining the pedal feel with
“virtual” resistance to foot pressure.
Optimum reliability, safety and longevity
By correcting any driver errors such as the accidental release of the pedal, inappropriate
“clutch-in” operation or misuse leading to wheel-lock, the system improves the lifetime of the
clutch and the vehicle transmission. The system also offers fully automatic clutch functions,
and will then contribute to anti-sliding and anti-blocking by preventing wheel lock.
Being more compact in design than a tradition clutch pedal, it also provides better protection
for the driver’s feet in case of accident.
The last, but not the least, advantage is that by supplying data about the real use of the clutch,
the ECU facilitates clutch maintenance.