Hill-holder


Hill-holder is a name for the mechanism invented by Wagner Electric and manufactured by Bendix Brake Company in South Bend, Indiana. It is a device that holds the brake until the clutch is at the friction point, making it easier to start up hills from a stop in manual transmission automobiles. Hill-holder works by holding the brake in position while the driver sets-up and activates the first gear to move the car forward from a complete stop, without fear of roll-back.
It was first introduced in 1936 as an option for the Studebaker President. By 1937 the device, called "NoRoL" by Bendix, was available on Hudson, Nash and many other cars. Studebaker and many other carmakers offered the device as either optional or standard equipment for many years. In modern usage, this driver-assistance system is also called hill-hold control, hill-start assist or hill-start assist control.

Availability

As a trade name, it was introduced by Studebaker in the 1936 President. It was also promoted by Studebaker as an option in the 1939 model year. Later, the technology became available on a variety of modern automobiles, starting with the 2005-onwards Volkswagen Passat, 2011-onwards Volkswagen Jetta, and 2004-onwards Volkswagen Phaeton and Touareg. It is further available on the Subaru Forester, Subaru Impreza and Subaru Legacy. The 2009 Dodge Challenger SRT8 also comes equipped with hill-holder.
Similar systems are or were in use by Alfa Romeo, Citroën, Fiat, BMW, Skoda Superb 2009, Lancia, Mercedes-Benz, Volkswagen, Lamborghini Aventador, Saab, smart, Subaru, Cadillac and Stutz.
The mechanism was available in American car parts stores so that car owners could add to their vehicle to improve it from the late 1930s through the 1950s. But it required that the car have hydraulic brakes, so it could not be added to Ford Motor Company products before 1939. In 1949 it became available on factory-built Fords.
Cars with hill-holder feature:
MakeModelYearCommentReference
VinFastFadil
LUX A2.0
LUX SA2.0		2019
SubaruOutback2003-2014above
SubaruImpreza2003above
SubaruLeone1984-1994above
SubaruLegacy1989-2015above
SubaruForesterJuly 2005above
SubaruVortex 1985-2001above
DodgeChallenger SRT82009
Alfa Romeo1592005
Fiat500 Sport2011
FordFiesta2012-Current
ChevroletSonic2012
HondaCR-Z2012Called "Hill Start Assist"
HondaFit and Fit Hybrid2015
ChevroletSpark2013Called "Hill Start Assist"
Mercedes-Benz SmartForTwo2011Called "Hill Start Assist"
Mercedes-BenzGL3202008
Mercedes-BenzM-Class2012
MINICooperPart of Dynamic Stability Control
ToyotaRAV4EV2012-2014Called "Hill-start assist control"
VolkswagenPassat2012
AudiA32012
KiaKia_Soul2012+Called "Hill Start Assist"
MazdaCX-3,5,72013+
BMW5-Series2012Called "Drive-off assistant"
MahindraE2O2013electric car
LadaVesta2015 - current
BMW3-Series2007+Called "Drive-off assistant"

Operation

In layman’s terms, the modern hill-holder function works by using two sensors, in concert with the brake system on the vehicle. The first sensor measures the forward-facing incline of the vehicle, while the second is a disengaging mechanism. The 1930s-1950s NoRoL used a ball bearing as a check valve in the hydraulic brake line; when the car was on an uphill incline, the ball rolled back and blocked the brake line - when the car was level or facing downhill, the ball rolled away, leaving the line free. The clutch linkage slightly dislodged the ball when the clutch was released, enabling the car to move away from a stop.

Manual transmission vehicles

When the driver stops the vehicle on an incline where the nose of the car is sufficiently higher than the rear of the car, the system is engaged when the driver's foot is depressing the brake pedal, and then the clutch pedal is fully depressed. Once set, the driver must keep the clutch pedal fully depressed but may remove the foot from the brake pedal. To disengage the system and move the car forward, the driver selects first gear, gently depresses the fuel pedal, and slowly releases the clutch pedal which at a point in its travel releases the braking system, allowing the car to proceed.

Usage

Hill-holder works best for those who are inexperienced with manual shift techniques, or in situations with heavy traffic in steep hilly conditions.
However the same technique can be accomplished by a driver through the use of the manual parking brake lever, coordinated with the brake, clutch, gear shift and accelerator. This is a standard technique in most countries where manual transmissions remain popular, for example the UK. Cars equipped with a parking brake pedal are not suited for this maneuver unless it is released by hand, for example in the Citroen XM.