Patent Application
20110023509
The subject system is an air conditioner system for vehicles that uses compressed air as the means of powering the airconditioner refrigerant cycle. This is different to systems that use mechanical or electrical means to power the refrigerant cycle.
The subject system is designed to capture and store braking energy that would otherwise be lost in the form of heat via the wheel brakes of the vehicle. Braking energy is used to compress air and recharge a compressed air reservoir while the vehicle is under deceleration. The air compressor can also be powered from the main vehicle engine or motor.
This system is different from other compressed air vehicle systems in that it does not provide motive power for the vehicle in any way.
The system provides environmental, performance and safety benefits:
The design of this system is such that it can immediately implemented on existing “conventional” internal combustion engine vehicles without major redesign while achieving significant fuel economies.
It also allows “automatic start/stop” technology to be used in high ambient temperature environments by allowing continued airconditioner operation even when the engine is temporarily shut down. It can also be used on electric or hybrid-electric vehicles to reduce the load and wear on the electric batteries caused by running a vehicle airconditioner system.
It is estimated that this system using compressed air can save up to 1 liter of fuel for every 100 kilometres under normal driving conditions with the airconditioner operating, increasing to 2 liters of fuel for every 100 kilometres under urban conditions with frequent acceleration and braking. This fuel economy would be further improved with the use of “automatic stop/start” systems which, with this system, can allow the airconditioner to continue running while the vehicle motor is stopped.
In tropical urban environments, the system offers significant environmental benefits by reducing or eliminating the need to operate a polluting internal combustion engine on a parked vehicle simply to run the vehicle's airconditioner. This system allows the airconditioning system to run for a period of time while the internal combustion engine is switched oil eliminating harmful kerbside exhaust pollution and eliminating the heat produced by an idling motor.
The maximum period of operation of the airconditioner is determined inter alia by: the size (volume) and the pressure rating of the compressed air reservoir(s), the ambient outside temperature and the target internal cabin temperature.
This system may also be retrofitted to existing vehicles with suitable modifications.
The descriptions and functions of the components shown in
Outside air is drawn into the INTAKE and compressed by the air compressor “B”. The Air Compressor “B” is driven off the vehicle internal combustion engine or electric motor via direct, geared, belt, hydraulic, electric or other drive connection through a Variable Clutch/Drive “A”. The drive from the engine is such that it can supplement “engine braking” by providing additional load on the engine via the variable clutch while the vehicle is decelerating.
The Variable Clutch “A” is a variable power drive that is controlled by the ECU depending on the Operation Modes tabulated below and the Pressure state of “D” (monitored by the pressure sensor P). The ECU will control the Variable Clutch to ensure progressive application and avoid harsh changes to the vehicle motion or engine speed. The Variable Clutch/Drive “A” can be mechanical, hydraulic, electric, electro-magnetic, etc., the important characteristics being that the power transmission from the engine to the compressor “B” can vary from 0% to 100% depending on the operation mode.
Compressed air is either used to recharge the reservoir “D” or to drive the compressed air motor “F” directly via the Bypass Line (optional). Heat created by the compression of the air is lost to the outside via the heat exchanger (or radiator) “C”.
The control Valve “E” is used to control the flow of compressed air to the Compressed Air motor “F”, which drives the Airconditioner Compressor “G”. The operation of Control Valve “E” is determined by the thermostat settings on the airconditioner unit and the energy mode determined by the ECU (see below). Control Valve “E” may be one-way or two-way depending on whether the bypass is fitted.
Exhaust Air from “F” which is below ambient temperature following decompression is used to further cool the airconditioner heat exchanger “H1”, thereby boosting the efficiency of the airconditioner. (To maximise the effectiveness of the cooling airstream, the airflow will be directed starting from the downstream end of the heat exchanger “H1”.)
Normal pressure state corresponds to reservoir at 50-70% of maximum capacity (ie: of maximum rated pressure) depending on reservoir size. The “headroom” is to allow for maximum recharging under braking. The ECU can be programmed to allow this “headroom” to increase if the vehicle is travelling at higher speeds, allowing greater recharging capacity under braking. The headroom will therefore depend on several factors, such as the particular vehicle weight and speed (which determine the maximum available kinetic energy that can be recovered), driving style of the owner/driver, and driving conditions (for example, hilly vs flat). The ECU can, if required, be programmed to use “fuzzy logic” to optimise the available “headroom” for recharging the reservoir under braking. The optimal condition is where the reservoir is 99.9% full following completion of a typical braking cycle.
Normal mode means the vehicle airconditioner will control the cabin air temperature to the desired settings regardless of the pressure state of the reservoir “D”. Low Energy Mode is Optional and if installed means the vehicle airconditioner will balance maximising the availability of remaining compressed air with internal cooling demand, ie: normally via reducing fan speed and targeting cabin temperature to within the range of the desired setting +3 C.
The emergency valve is operated to release compressed air rapidly from “D” in case of an accident impact. This is to minimise the risk of uncontrolled decompression of the reservoir. Control is from impact sensors elsewhere in the car via the ECU. Under certain specifications, this compressed air can alternatively be used to inflate additional air bag safety systems, internal or external.
The simplified version is mainly mechanical with limited electronic control. The variable clutch is replaced by a fixed or limited variability drive (eg: binary state, on/off), such that the air compressor is continuously operating up to approximately 50%-70% of reservoir capacity, thereafter it operates only when the braking system is applied. This system does not offer all the benefits of the ECU-controlled system, the main benefit being to allow the airconditioner to continue to operate once the main engine is switched “off”. This simplified system may have application to ultra low-cost vehicles in tropical climate or high ambient temperature countries.
As noted above, the ECU can also be replaced by mechanical, electro-mechanical, or other forms of control system which achieve the same, or broadly similar, results as the proposed ECU.
| Number | Date | Country | |
|---|---|---|---|
| 61271941 | Jul 2009 | US |
