Car controls

In the Ford Model T, the pedals control the two forward gears (left pedal), reverse (center pedal), and the brake (right pedal). The steering-column levers control ignition timing (left) and the throttle (right). The large hand-levers set the rear-wheel parking brake and put the transmission in neutral (left) and control an after-market 2-speed transmission adapter (right).

Car controls are the components in automobiles and other powered road vehicles, such as trucks and buses, used for driving and parking.

While controls like steering wheels and pedals have existed since the invention of cars, other controls have developed and adapted to the demands of drivers. For example, manual transmissions became less common as technology relating to semi-automatic and automatic transmissions advanced.

Earlier versions of headlights and signal lights were fueled by acetylene or oil. Acetylene was preferred to oil, because its flame is resistant to both wind and rain. Acetylene headlights were popular until 1898, when the first electric headlights were introduced.

Steering

1969 Citroen DS Pallas interior with hydraulic gear selector mounted top right of steering column with a single spoke steering wheel. Note the so-called mushroom brake pedal. (The pedal on the left is the parking brake).

The first automobiles were steered with a tiller. The steering wheel was first used when Alfred Vacheron competed in the 1894 Paris–Rouen motor race in a Panhard et Levassor. In 1898, steering wheels became a standard feature of Panhard et Levassor cars. They were introduced in the U.S. by Packard in 1899.

Power steering helps drivers steer by augmenting the driver's steering effort. Power steering has used hydraulics to reduce a driver's steering effort. However, hydraulic steering is being replaced by electric power steering, because it eliminates the hydraulic pump, and increases fuel efficiency.^[1]

Pedals

Hanging pedals in a Subaru Legacy. From left to right: foot rest, clutch, brake, throttle.

Standing pedals in a Saab Sonett. From left to right: clutch, brake, throttle.

Foot pedals are levers that are activated by the driver's feet to control certain aspects of the vehicle's operation. Pedals usually hang from the bulkhead on smaller vehicles, while typically standing on the floor in heavy-duty vehicles. Regardless of where the pedals are mounted, the arrangement is the same for both right- and left-hand traffic. The following pedals are positioned in left-to-right order:

• parking brake pedal (replaces the hand lever in some automatic transmission vehicles)
• clutch pedal (if the vehicle is not equipped with automatic transmission)
• brake pedal
• throttle (controls fuel and air supply to the engine and is also known as the "accelerator" or "gas pedal") The accelerator has a fail-safe design – a spring, which returns it to the idle position when not depressed by the driver.

Normally the throttle and brake are operated by the right foot, while the clutch is operated by the left foot. In the US, drivers who mistake the accelerator for the brake, leading to sudden unintended acceleration, cause 16,000 accidents per year.^[2] However, there are drivers who practice left-foot braking.

Transmission

A floor-mounted gear lever in a modern passenger car with a manual transmission

Vehicles that generate power with an internal combustion engine (ICE) are generally equipped with a transmission or gearbox to change the speed-torque ratio and the direction of travel. This does not usually apply to electric vehicles because their motors can drive the vehicle both forward and backward from zero speed. In some four-wheel drive vehicles there is a gear lever that engages a low-ratio gearbox. Other levers may switch between two- and four-wheel drive and differential locks.

Some cars have a freewheel that disengages the driveshaft from the driven shaft. This happens when the driven shaft rotates faster than the driveshaft. For example, Saab used a freewheel system in the Saab 96 V4 and early Saab 99 for better fuel efficiency. It was also used in Saab's two-stroke models at the cost of engine braking. Some cars, such as the Rover P4, include a manual switch to engage or disengage the freewheel.^[3]

Manual

Manual transmission is also known as a manual gearbox, stick shift, standard, and stick. Most automobile manual transmissions have several gear ratios that are chosen by locking selected gear pairs to the output shaft inside the transmission. Manual transmissions feature a driver-operated clutch and gear stick. Historically, cars had a manual overdrive switch.

Automatic

The desire for driver convenience led to the widespread implementation of the semi-automatic transmission, automatic transmission and continuously variable transmission (CVT). Some automatic transmission vehicles have extra controls that modify the choices made by the transmission system. These controls depend on the engine and road speed. Automatic transmissions generally have a straight pattern, beginning at the most forward position with park, and running through reverse, neutral, drive, and then to the lower gears.

Signals and lighting

Cars have controls for headlamps, fog lamps, turn signals, and other automotive lighting. Turn signals are activated by the driver to alert other drivers of their intent to turn or change lanes.^[4] While the modern turn signal was patented in 1938,^[5] electric turn-signal lights date back to 1907.^[6]

As of 2013, most countries require turn signals to be included on all vehicles driven on public roadways. The turn signal lever is usually activated by a horizontal lever protruding from the steering column.

Instrumentation

An analog speedometer using kilometres per hour (km/h). Immediately below is a digital odometer. Partially visible on the left and right are the tachometer and fuel gauge.

Vehicles are generally equipped with a variety of instruments mounted on the dashboard to indicate driving parameters and the state of the mechanics. The placement of the instruments can vary. While they are usually mounted behind the steering wheel, they may also be mounted centrally below the windshield, or integrated into the center stack above the climate control and audio system. The standard gauges found on road vehicles include the following:

• Speedometer
• Tachometer
• Odometer
• Fuel gauge
• Engine temperature gauge
• Ammeter
• Oil pressure gauge

These gauges are supplemented by an assortment of warning lights that indicate the currently selected transmission gear mode, the generic check engine light, and the current status of various vehicle systems.

The layout and design of these instruments have evolved over the years by being implemented as digital readouts rather than the traditional analog dial-type indicators. Depending on the type of vehicle, more specialized instruments may be used such as a trip computer, fuel economy gauge, or battery level display.

Starting and running the engine

1917 Packard crank holder

Before the appearance of the starter motor, engines were started by various difficult and dangerous methods. These methods included: wind-up springs, gunpowder cylinders, and human-powered techniques such as a removable hand-crank. In 1896, the first electric starter was installed on an Arnold,^[7] one of the first motor cars manufactured in the United Kingdom. Charles Kettering and Henry Leland later invented and filed U.S. Patent 1,150,523 for the first electric starter in America in 1911. In 1912, the Cadillac Model Thirty became the first American car to have a starter installed.

Before Chrysler's 1949 innovation of the key-operated combination ignition-starter switch,^[8] the starter was operated by the driver pressing a button that was mounted on the floor or dashboard. This type of control has now returned with the use of keyless entry. Early Chevrolet cars had the starter pedal to the right of the accelerator, with a secondary throttle control knob on the dashboard because it was difficult to operate the starter pedal and the throttle pedal at the same time.

Early cars such as the Ford Model T had a hand lever to control the throttle.^[9] Later cars used both a foot pedal and a hand lever to set the minimum throttle. This was an early form of cruise control. The 1918 Stutz Bearcat had a central throttle pedal with the clutch and brake to the right and left.^[10] Modern cruise control was invented in 1948.^[11]

Some other historical engine controls, which are automated in modern cars, were the choke valve, ignition timing, and spark arrestor.^[12]

Additional controls

In the past, all cars had manual controls for starting and running the engine. Now, modern cars not only have automated controls, but they also have controls that are not directly used to drive the vehicle. These controls include air conditioning, navigation systems, on-board computers, in-car entertainment, windscreen wiper, and touchscreen panels.

These controls vary in scope and design between different types of cars. They may also be located and operated differently in other road vehicles such as motorcycles, where the throttle is controlled by a hand lever and the gear shift is operated by a pedal. Some types of vehicle controls are found in rail vehicles. For example, some trams and light rail vehicles like the PCC streetcar use automobile-style pedals to control the speed.

See also

• History of the automobile

References