GB2291221A

GB2291221A - Car defrost control system

Info

Publication number: GB2291221A
Application number: GB9414283A
Authority: GB
Inventors: Cameron Thomas Screen
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-07-15
Filing date: 1994-07-15
Publication date: 1996-01-17
Also published as: GB9414283D0

Abstract

A car defrost control system actuates a car's engine and electrical system, with the driver absent, at a preset time and for a given duration. The driver would set the heater/blower and demister switches before leaving the car. As the engine warms so the car would defrost. Sensors ensure that the engine is not capable of starting or running when the car is in gear, or continue to run in the event of high exhaust fume levels, such as might be experienced in the confines of a garage. <IMAGE>

Description

CAR DEFROST CONTROL SYSTEM This invention relates to the preset and automatic start-up of a car's heating and defrost systems in the absence of the driver.

There are many days during Winter when cars left outside have to be defrosted before use. Because this practise is uncomfortable it is often performed insufficicently well, resulting in cold uncomfortable cars with restricted visibility. This has serious safety implications to the driver and other road users. A certain way to fully warm and defrost a car is to run the engine with the heater/blower and rear window demister systems on.

According to the present invention there is provided a car defrost control system which will switch a cars electrical and starter motor systems on automatically and safely, with the driver absent, at a time preset by the driver and for a set duration.The driver would set the heater/blower and rear window demister switches before hand. As the engine warms so the car would warm and defrost.Safety considerations demand, however, that the engine must not be capable of starting when the car is in gear, or continue to run in the confines of a garage. The car's defrost control system ensures this through sensors located in the gear box and near the exhaust exit.

A specific embodiment of the invention will now be described by way of example with reference to figure 1.

The defrost control system is comprised of seven essential components listed below. The mode of operation will then be described.

Component 1 is a timing device, timer 1, that can be preset to turn 'on' and 'off' at required times. The likely function would be for the driver to set the 'start time' and have a factory set duration to prevent excessive running of the engine.The timer 1 is powered at all times and is capable of supplying power to the gas sensor 2, gas monitor 3,gearbox switch 4 and relay switch 5.The power supply to the gas sensor 2 and gas monitor 3 would be made up to one hour or so before the set 'start time' to allow these components to precondition. Power would be supplied to the gearbox switch 4 and relay switch 5 at the 'start time'.The relay switch 5 would 'close' for the duration of the timer.

Components 2 and 3 are the gas sensor 2 and gas monitoring 3 components for the car's exhaust emissions. These emissions comprise of various gases which are capable of detection. A suitable gas for detection in this application would be, although not limited to, carbon monoxide.The sensor 2, which is commercially available, produces when powered an electrical output proportional to the concentration of carbon monoxide detected. At factory set limits for the output from the gas sensor 2, the monitor 3 would 'open' (carbon monoxide level high) or 'close'(carbon monoxide level low) the relay 6. 'High' carbon monoxide levels would be seen if the engine was running whilst the car was garaged,'low' levels would be seen in the open air.The gas sensor 2 would be positioned at the rear of the car near the exhaust outlet and protected from the weather by a cowling.

Component 4 is a gearbox switch which will only allow the passage of an electrical signal from the timer 1 to the relay switch 7 if the gear lever is in a neutral position ( ie out of gear ).The electric signal to the relay switch 7 would cause it to 'close'.

Components 5,6 and 7 are electrical relay switches 5,6 and 7 which default to the 'open' position when not powered, as shown in figure l.Power from the timer 1, gas monitor 3 and gearbox switch 4 cause the respective relays 5,6 and 7 to close.

A to B is an electric bypass of the cars electrical system and starter motor circuits as connected to the car's ignition switch.When the relays 5,6 and 7 are closed the car engine will start and run until any one relay is opened.However, because the ignition switch is bypassed, a delay switch capable of turning off the starter motor after one second or so, would be required in the starter motor circuitry.

The mode of operation is as follows.

a) The driver sets the heater/blower controls and rear window demister switch to the on position, and sets the timer 1 'start time'. The car ignition would be off at this stage. The driver then leaves and secures the car.

b)About one hour before the timer 1 'start time' is reached the gas sensor 2 and monitor 3 are powered to allow them to precondition.

c) When the timer 1 reaches the 'start time' the relay 5 will close. The gas monitor 3 will close relay 6. If the car is in neutral the gear box switch 4 will close the relay 7.With relays 5,6 and 7 closed the A to B electric bypass line will be complete and the car engine will start.

d)The car engine will run and the car will defrost until either the timer 1 duration expires,opening relay 5; or the carbon monoxide level increases to unsafe levels,in which case the gas sensor 2 will detect this and the monitor 3 will open the relay 6;or if the car is placed in gear, inwhich case the gear box switch 4 will open relay 7.

Claims

1) A car defrost control system which will automatically start and stop a cars engine and electrical system to allow the cars heating and defrost equipment to operate. Means are provided to preset the start and stop times of the engine, to safeguard against high levels of exhaust fumes, and to prevent operation of the engine whilst the car is in gear.

2) A car defrost control system as claimed in claim 1, wherein the start and duration of the engine running is controlled by a timer linked to an electric relay switch in the electric bypass line A-B (figure 1).

3) A car defrost control system as claimed in claim 2, wherein the use of a gas sensor and monitor linked to an electric relay switch in the electric bypass line A-B (figure 1), ensures that the engine will not run if exhaust gas levels become too high.

4) A car defrost control system as claimed in claim 3, wherein the use of a gear box switch linked to an electric relay switch in the electric bypass line A-B (figure 1), ensures the engine will not operate if the car is in gear.

5) A car defrost control system as claimed in claim 4, wherein the electric bypass line A-B (figure 1) has a number of electric relays linked in series. When all relays are closed then the cars electrical and starter motor switches are bypassed, opening of a relay will prevent this.

6) A car defrost control system as shown in figure 1.