Glossary

The Glossary is organized in alphabetical order. If you would like to see just the entries for a particular letter, choose from below.
Active Safety (ABS, VSC, TRAC)

A vehicle's safety features or equipment that help avoid collisions. (Examples: ABS, VSC, TRAC, etc.)

Anti-Lock Brake System (ABS)

Anti-lock Brake System (ABS) Computer-controlled ABS modulates brake pressure during hard braking to help avoid wheel lock-up and maintain steering control. When the wheels begin to lock, the computer causes the brakes to pulse more rapidly than humanly possible, allowing the wheels to rotate rather than skid.

Battery

An electrochemical device that converts chemical energy into electrical energy. Typical automotive batteries supply the source of power for cranking the engine and also the electrical energy for the ignition system.

Brake Assist (BA)

In emergencies, some drivers, especially inexperienced ones, often panic and do not apply sufficient pressure on the brake pedal. Brake Assist measures the speed and force with which the brake pedal is pushed to determine whether the driver is attempting an emergency stop. If the system determines that is the case, it applies additional brake pressure to allow the driver to take full advantage of the ABS brake system. When the driver intentionally eases up on the brake pedal, the system reduces the amount of assistance it provides. This feature comes with VSC.

Crumple Zones

These exist at the front and rear of the vehicle to help absorb the impact of a collision. These pre-stressed areas in the fender, hood, frame and related body components are designed to deform in a predetermined manner during collision. Their purpose is to help lessen the force the impact transfers to the passenger compartment. In essence, the crumple zone of a vehicle is sacrificed to help protect the occupants.

Differential

A gear assembly that allows one driven wheel to turn at a different speed from the wheel on the other end of the axle. This is necessary since an outside wheel has farther to travel than an inside wheel when turning a corner.

Drive configuration

Refers to where the engine is placed in the vehicle and which wheels power the vehicle.

Driving Simulator

Enclosed in a large dome, a spherical screen displays high-resolution images that stretch 360 degrees around a driver. The machine reproduces the sensations of actually driving a car, including road vibrations and road and wind noise. To help ensure the realism of the driving experience, the entire testing chamber is mounted on a hydraulic lift that shifts and pivots to reproduce the feeling of acceleration and deceleration, as well as the sensation of driving around a curve. The Driving Simulator makes possible an entire class of experiments that would otherwise be impossible, even in the controlled environment of a test course. The system allows engineers to safely test hazardous driver behavior such as falling asleep at the wheel, looking away from the road, and even driving under the influence.

Dynamic Laser Cruise Control (DLCC)

Dynamic Laser Cruise Control function has two cruise control modes: a vehicle-to-vehicle distance control mode for maintaining an appropriate distance between two vehicles, and a conventional fixed-speed cruise control mode for cruising at preset speeds.

Electrical System

The system that cranks the engine for starting, supplies high voltage to the spark plugs, powers the lights, and operates other accessories and electrical equipment.

Electronic Brake-force Distribution (EBD)

This system optimizes the braking effort distributed between front and rear axles. Vehicle stability during braking is improved in conditions that fall short of triggering the ABS. EBD helps minimize stopping distances regardless of load conditions.

Electronic Control Module (ECM)

Electronic Control Module.

Electronic Throttle Control with intelligence (ETCS-i)

This system replaces the mechanical cable-operated throttle control with an electronic version with inputs from the accelerator pedal and engine control module. The system is more precise, more efficient and quieter. It also controls the cruise control system and engine idle speed when the air conditioning system or other accessories are turned on.

EPA-estimated fuel economy

Mileage figures arrived at through laboratory tests conducted by the Environmental Protection Agency (EPA). Mileage figures for city and highway driving are usually reduced by a set factor to more closely reflect "real-world" driving.

Force limiters

Front seatbelt safety feature that helps reduce the load of the seatbelt on an occupant's chest, thereby reducing the risk of injury from the seatbelt itself.

Hybrid Synergy Drive®

Refers to Toyota's name for advanced technology hybrid powertrains that combine gasoline and electric propulsion with the ability to operate on one or the other, or both, depending on the driving situation. By enabling the vehicle to operate at its most efficient level, regardless of engine speed, Hybrid Synergy Drive® boosts power output and, at the same time, enhances efficiency and emissions control.

Hydrogen Fuel Cell Hybrid Vehicle (FCHV)

The Toyota Fuel Cell Hybrid Vehicle advanced (FCHV-adv) is based on the popular Toyota Highlander mid-size sport utility vehicle. It utilizes the same core hybrid synergy drive (HSD) technology utilized in the Toyota Prius. The FCHV-adv fuel cell system features four compressed hydrogen fuel tanks, an electric motor, a nickel-metal hydride battery, and a power control unit. Hydrogen gas is fed into the fuel cell stack where it is combined with oxygen. The electricity produced by this chemical reaction is used to power the electric motor and to charge the battery.

Intelligent Transport Systems

Advanced transport systems that are constructed to integrate people, vehicles, and the traffic environment, using state-of-the-art information and communication technologies to build a safe, comfortable and smooth transport infrastructure.

Lithium-Ion Battery

Lithium-ion battery electrodes are composed of lightweight lithium and carbon. Lithium is a highly reactive element, meaning that a lot of energy can be stored in its atomic bonds.

Nickel Metal Hydride Battery

The components of NiMH batteries include a cathode of Nickel-hydroxide, an anode of Hydrogen absorbing alloys and a Potassium-hydroxide (KOH) electrolyte. The energy density of NiMH is more than double that of a lead acid battery but less than lithium ion batteries.

Passive Safety

A vehicle's safety features or equipment that help protect occupants in the event of a collision. (Examples include crumple zones, seatbelts, airbags, etc.)

Plug-In Hybrid Vehicle (PHV)

The Prius Plug-in Hybrid (PHV) is based on the third-generation Prius. The vehicle represents a significant enhancement of Toyota's Hybrid Synergy Drive® (HSD) system. It combines high-output lithium-ion batteries with HSD technology to offer an expanded fully electric driving mode.

Regenerative braking

An advanced type of braking system that is found on electric or hybrid vehicles, it works together with an electric motor to slow the vehicle and, at the same time, recapture the vehicle's energy to help recharge the hybrid's battery. With this type of brake system, the hydraulic brakes usually operate in only the last few moments of braking for great braking performance and reduced wear on the front brake pads. (Featured on the Toyota Hybrids.)

Seatbelt Pretensioners With Force Limiters

Seatbelt pretensioners cinch the seatbelts during certain types of frontal impacts. Pretensioning can help the belt to immediately begin absorbing the occupants' forward momentum and help them avoid injury. All Toyota vehicles with seatbelt pretensioners also feature force limiters. After the pretensioners deploy and a preset amount of force has been reached, force limiters slowly release tension on the belt to help absorb the energy of an impact.

Sustainable Mobility

Advanced technologies needed to develop transportation technologies to reduce the environmental impact of human mobility.

Star Safety SystemTM (STAR)

Toyota's Star Safety SystemTM consists of five mechanisms that work together to help keep Toyota drivers in control. They are:

  • Anti-lock Braking System (ABS)
  • Electronic Brake-force Distribution (EBD)
  • Vehicle Stability Control (VSC)
  • Traction Control (4-wheel on 4WD models; includes auto limited-slip rear differential function on 2WD models)
  • Brake Assist (BA)

Total Human Model for Safety (THUMS)

An experimental virtual model of the human body that includes not just the exterior shape, but also internal structures like organs, bone, ligaments, tendons, and muscle. This advanced experimental approach to crash testing simulates the injuries sustained in actual car crashes. As a result, the model is able to detect and predict the most common injuries reported in accident data analysis.

Traction Control (TRAC)

The sophisticated Toyota system is an all-speed design that utilizes both brake and engine throttle control. TRAC helps to avoid slippage of the driving wheels by slightly applying the brake on a slipping drive wheel and reducing the throttle to maintain traction according to the road surface conditions. The system eliminates the need for a subtle accelerator pedal operation and helps ensure vehicle control when starting or accelerating on slippery roads.

Variable Valve Timing and Lift with intelligence (VVTL-i)

Based on the VVT-i system, the VVTL-i system has adopted a cam changeover mechanism that varies the amount of lift of the intake and exhaust valves while the engine is operating at high speeds. In addition to achieving higher engine speeds and higher outputs, this system enables the valve timing to be optimally set, resulting in improved fuel economy. When the engine is operating in the low- to mid-speed range, the low- and medium-speed cams of the camshafts operate to move the two valves via the rocker arms. Then, when the engine is operating in the high-speed range, the signals from the sensors cause the engine's control module (ECM) to change the hydraulic passage of the oil control valve (for the variable valve lift), thus changing to the operation of the high-speed cams. Now the lift of the intake and exhaust valves increases, allowing the introduction of a greater volume of air-fuel mixture, as well as the discharge of a greater volume of exhaust gases. As a result, the engine operates at higher speeds and higher outputs when the engine is under more strain.

Vehicle Stability Control (VSC)

The VSC system electronically monitors speed and direction, and compares the vehicle's direction of travel with the driver's steering, acceleration and braking inputs. VSC can help compensate for loss of traction which can cause skids. It utilizes some components shared with the Anti-lock Brake System (ABS) and an electronically controlled engine throttle as well as a dedicated computer and sensors providing information to the VSC system. These include a yaw rate sensor, a G-sensor and a steering angle sensor. When VSC is active, a warning beep tone and instrument panel warning light indicate that the system is functioning. In many cases, VSC reacts well before the driver is aware of a loss of traction. As with other safety technologies, such as anti-lock brakes, it is important to drive safely, since Vehicle Stability Control cannot defy the laws of physics, nor can it provide more traction than exists in a given condition.

Whiplash

Whiplash injuries occur when the forces of a rear-end collision cause the head and torso to move relative to one another.

Whiplash Injury Lessening (WIL) Concept Seat

Testing has shown that it is important for the seatback and headrest to simultaneously restrain the occupant's head and torso during an impact, and so Toyota reassessed the position of the setback frame and headrest in designing the WIL concept seats.