Showing papers by "Land Rover published in 2002"

Aerodynamic Drag of a Compact SUV as Measured On-Road and in the Wind Tunnel

Abstract: Growing concerns about the environmental impact of road vehicles will lead to a reduction in the aerodynamic drag for all passenger cars. This includes Sport Utility Vehicles (SUVs) and light trucks which have relatively high drag coefficients and large frontal area. The wind tunnel remains the tool of choice for the vehicle aerodynamicist, but it is important that the benefits obtained in the wind tunnel reflect improvements to the vehicle on the road. Coastdown measurements obtained using a Land Rover Freelander, in various configurations, have been made to determine aerodynamic drag and these have been compared with wind tunnel data for the same vehicle. Repeatability of the coastdown data, the effects of drag variation near to zero yaw and asymmetry in the drag-yaw data on the results from coastdown testing are assessed. Alternative blockage corrections for the wind tunnel measurements are examined. A reasonable correlation between wind tunnel and on-road aerodynamic drag data is established for the configurations tested.

Traction control system

Abstract: A vehicle brakes traction control system and method of operation, for a vehicle having a drive axle with a differential operable between wheels at the two ends of the axle, and brakes for each respective wheel operable by a brake controller. The traction control system includes wheel speed sensors sensing the rotational speed of the wheels, an engine torque demand sensor and an engine torque output monitor. The brake system controller receives signals from the wheel speed sensors, the engine torque demand sensor and the engine torque output monitor to apply the brakes to equalize the rotational speed of the wheels if the engine torque output is less than a desired torque output for a given torque demand.

A vehicle speed control system

Abstract: A vehicle speed control system includes an engine control system 36 with an engine idle speed controller 37 which maintains the engine idle speed set point I for varying engine torque outputs, and a vehicle braking system 13,14,20, for braking the vehicle and which is operated by a deceleration demand means 22,32. The idle speed controller 37 is arranged to receive signals from the deceleration demand means 22,32 and any increase in engine torque output demanded by the idle speed controller 37 to maintain idle speed is limited in response to signals received from the deceleration demand means 22,32.

Vehicle brakes traction control for increasing engine output torque

Abstract: For a vehicle having a driven axle 11 with a differential 17 operable between wheels 12,13 at the two ends of the axle 11, a brakes traction control system includes several wheel speed sensors 14 to sense the rotational speed of said wheels, an engine torque demand or throttle opening sensor 21, an engine torque output monitor 22, and a programmable brake system controller 18. In the event of a wheel spinning, the controller 18 applies one of the vehicle brakes 15, 16 to equalise the rotational speed of the wheels and slow the engine speed only if such an application will increase engine torque output towards a maximum torque output for the sensed torque demand. Thus maximum torque may be transferred to the other wheel, and engine stall or vehicle immobilisation is prevented. If the maximum torque is available over a range of engine speeds, a target engine speed giving the maximum torque value is chosen in dependence on the rate of change of the throttle opening.

A traction control system

Abstract: A vehicle brakes traction control system and method of operation, for a vehicle having a drive axle (11) with a differential (17) operable between wheels (12,13) at the two ends of the axle (11), and brakes (15,16) for each respective wheel (12,13) operable by a brake controller (18). The traction control system includes wheel speed sensors (14) sensing the rotational speed of said wheels, an engine torque demand sensor (21), and an engine torque output monitor (22). The brake system controller (18) receives signals from the wheel speed sensors (14), the engine torque demand sensor (21) and the engine torque output monitor (22) to apply the brakes (15,16) to equalise the rotational speed of said wheels (12,13) if the engine torque output is less than a desired torque output for a given torque demand.