WO2012153198A2

WO2012153198A2 - Automatic transmission fluid temperature warning system

Info

Publication number: WO2012153198A2
Application number: PCT/IB2012/001602
Authority: WO
Inventors: Wasfi Alshdaifat
Original assignee: Almuhairbi, Eida
Priority date: 2012-08-13
Filing date: 2012-08-13
Publication date: 2012-11-15
Also published as: WO2012153198A3

Abstract

As keeping pressing on the brake pedal for long periods with the transmission (20) shift lever (23) at D position in vehicles, causes the torque converter (25) to churn the ATF (21), and so ATF overheating results which causes serious damages to the transmission (20) operating parts, a monitoring (warning) system (26) is provided. By collecting data from the ATF temperature sensor, transmission shift position sensor, engine speed, vehicle speed, ABS wheels speed sensors, coolant temperature sensor, and Auxiliary fan speed, to feed it into a microprocessor (35), the system carry out three operations. The first: by warning the driver via a warning message how to act, while a warning sound is provided if the driver did not act. The second: by increasing the Auxiliary fan speed. The third: by carrying out calculations of the evaluated remaining age or mileage for the ATF, and warning the driver when to replace it.

Description

AUTOMATIC TRANSMISSION FLUID TEMPERATURE WARNING SYSTEM Description of the Invention

Technical Field of Invention

The rise of automobiles transmissions fluids temperatures over limits causes overheating to the fluid, which degrade its life; tranmssion parts damage results, many monitoring systems are used to monitor such overheating conditions.

Background Art

Some fluids in automobiles are exposed to overheating which causes serious damages for the systems where they operate, so fluids temperatures monitoring systems are used in automobiles, basically as a standard in cooling systems related to radiator coolant, such as the coolant fluid temperature monitor disclosed in patent No.: US 5,531,191 dated: Jul.2, 1996, temperature sensor for automobile disclosed in patent No.: US 8,029,181 B2. Temperature sensors are used also to monitor transmission fluids; these are disclosed in patents No.: US 4,488,140, and Patent Pub. No.: US 2008/0077297 A1. While in general, temperature measurement devices are disclosed in many patents such as patent No.: US 7,819,578 B2

Warning systems are used to warn the drivers from measured overheating conditions, many sytems are used to indicate a fault and provide the data through the instrument cluster, either via warning messages, warning lights, warning sounds or all of these in one system, examples: US 4,184,146, US 6,198,388 B1, US 6,289,332 B2 and Int. Publication No.: WO 2011/126956 A1.

Even most transmissions of running vehicles nowadays are filled with Dexeron III ATF, drivers are believing it is a long life fluid, even it is supposed to be good for 100,000 miles, but the most important fact is that the majority of the drivers did not know what dramatic results comes from transmission fluid overheating, on this supposed mileage life.

All automatic transmissions create a lot of internal heat through friction: the friction of the fluid churning inside the torque converter, friction created when the clutches plates engage, and the normal friction created by gears and bearings carrying their loads.

It doesn't take long for the ATF to heat up once the transmission is running, the normal operating temp, for the ATF is 79.5° C, but once this temp, goes much higher, the life of the fluid begins to decrease, the reason is that the heat destroys the fluid lubricating qualities and friction characteristics, varnish begins to form on internal parts (such as the valve body) which interferes with the operation of the transmission.

As per ATF manufactures, if the temp, gets above 121° C, rubber seals begin to harden, which leads to leaks and pressure losses, at higher temperatures the transmission begins to slip, eventually clutches burn out, the only way to repair it is either an overhaul with average cost of 1,500 $, or replace it with a new one, with average cost range: 5,000 - 10,000 $.

As a rule, every 11°C increase in the operating temperature above the 79.5° C normal operating temperature, cuts the life of the fluid in half, the most serious fact is that most of transmissions encounter a temp. Increase up to 105° C, which cuts the life of the fluid into a quarter (25,000 miles).

A major reason for ATF temperature increase, is that while waiting at traffic lights or roundabouts...etc, most of the drivers keep the transmission shift lever at D position, while holding the vehicle unmoving by pressing at the brake pedal, unaware that at this situation the torque converter which contains 1/3 of the transmission fluid is left running; building up heat in the ATF.

Because at this situation the vehicle is not moving, the cooling will be poor over the ATF in the torque converter, it is poor either through the ATF cooling unit (heat exchanger) or the transmission housing fins, while the most serious issue, is that inside the torque converter, the ATF is isolated and located far away from a natural cooling, but close to the engine heat, this issue, which is not disclosed by any prior art, with no warning system developed for it, is handled here, and a monitoring system is developed for it as a major and serious cause for ATF overheating, and transmissions damages. Disclosure of Invention

Brief Description

As drivers are unaware that keeping pressing on the brake pedal for long periods with the transmission shift lever at D, will cause the torque converter to churn 1/3 of the ATF that is contained inside it, and as a result ATF overheating results which causes serious damages to the transmission operating parts, a monitoring (warning) system is provided.

By collecting data from the ATF temperature sensor, transmission shift lever position sensor, engine speed, vehicle speed, ABS wheels speed sensors, coolant temperature sensor, and Auxiliary fan speed, coolant thermostat, to feed it into a microprocessor, the system carry out three operations.

The first is by warning the driver via a warning message how to act, while a warning sound is provided if the driver did not act. The second operation is by activating and increasing the Auxiliary fan speed, and actuating the thermostat. The third operation is by carrying out calculations of the evaluated remaining age or mileage for the transmission fluid, and warning the driver when to replace it.

Brief Description of the Drawings:

• FIG. 1 : Illustrates a flow chart for the ATF temperature warning system. · FIG. 2: Illustrates a view of the control system for the ATF temperature monitoring.

Best Mode for Carrying out the Invention:

From experience with service centers for American, European, and Japanese automobiles in the Arabian Gulf region, the data analysis for the reasons that are standing mainly behind the transmissions 20 break downs, and secondly for transmissions 20 leaks, were indicating that more than 90% of these defects were related to a burnt transmission fluid 21. These results also agree with most automatic transmission rebuilders around the world, according to whom 90% of all transmissions 20 failures are caused by overheating. And most of these can be blamed on worn out fluid 21 that should have been replaced. Even though it is well-known worldwide that any number of reasons can push ATF 21 temperatures beyond the system ability to maintain safe limits: 1- towing a trailer, 2- mountain driving, 3- driving at sustained high speeds during hot weather, 4- stop-and-go driving in city traffic, 5- shifting the automatic transmission 20 from drive to reverse to free a wheel from mud or snow, 6- cooling system 22 poor performance or defected parts; it is found by the inventor that there are still further main reasons for the problem: a- Keeping the transmission shift lever 23 at D position while pressing the brake pedal under hot outside summer condition like in the Arabian gulf region where the average temperature under the sun at summer mid-noon is in-between 45-50°C, b- driving and climbing sand hills and mountains under the same summer conditions.

Via personal investigation with the customers who own vehicles that got defects in their transmissions 20, it is found by the inventor that around 30% of them did not face any problem like those mentioned in points 1 , 2, 3, 5, and 6 or like that in point b, rather the reason was because they always kept it as a habit in stop and go traffic to keep the brake pedal pressed while the transmission shift lever 23 is put at drive position.

Further tests and comparisons carried out by the inventor on the ATF 21 quality changes under two conditions: a- shifting the transmission 20 to neutral at stop and go traffic, b- applying brake with transmission shift lever 23 put at drive at stop and go traffic, these provided results that showed in 100% of the cases, the ATF 21 fluid quality were degraded at the case of point b, wherein the ATF 21 were burnt, with little varnish appearing to stick on the magnet, and viscosity is lowered, this happens because while the engine 24 is running at idle, and the transmission shift lever 23 is kept at D, with the brake pedal pressed, the torque converter 25 will be running useless, but as 1/3 of the ATF 21 is churning inside the torque converter 25 without cooling, it will build up heat, and then overheats.

These results show how much a solution for such a manner by the drivers is a necessity, but this solution will solve part of the problem, as the other reasons of ATF 21 temperature rise, or even driving on a burnt ATF 21 or the unawareness of degraded ATF 21 life date of replacement should also be considered into account, and included in the solution.

The best conventional solution for such cases is to develop a warning system 26 that monitors all of parts and data related to ATF 21 overheating, and announcing the results to the driver in a form of warning messages and even with a warning sound.

To design such a system 26, it is required at first to pinpoint all the conditions, parts, sensors, actuators, and systems that are related to the ATF 21 overheating, or those which provide data that help in monitoring ATF 21 temperature rise data gathering. These can be limited in the followings:

1- Conditions: a- ATF 21 temperature rise up over 79.5°C, b- Engine 24 running at idle with transmission shift lever 23 at drive while brake is applied for a period of time. C- engine coolant temperature.

2- Sensors: a- ATF temperature sensor 27 to provide a reading for the transmission fluid 21 , b- Transmission shift lever position sensor 28, to indicate if transmission shift lever 23 is at D position, c- Vehicle speed sensor 29 signal and ABS wheels speed sensors 30 signal to indicate if the vehicle speed is zero, d- engine speed sensor 31 to indicate if engine 24 is running at idle, f- coolant temperature sensor 32 to indicate if the coolant is overheating.

3- Actuators: Auxiliary fan 33 (speed), map coolant thermostat 34 (opening degree). These two parts can help in activating the cooling system to create a lower effect of the engine cooling system 22 either on the ATF 21 cooling unit, or on the whole transmission 20.

4- A microprocessor 35 to receive data, process it, to do the followings: a- to issue a warning message or warning sound to the driver via the instrument cluster 36 or information center 37, b- to activate the Auxiliary fan 33 and open the map coolant thermostat 34, c- to issue a reminder message about the remaining mileage for replacing the ATF 21 , by calculating and estimating the remaining mileage age of the ATF 21 according to the gathered data about the operating conditions that are affecting ATF 21 fluid age degradation, and processing it via a built-in program inside the microprocessor 35 for this sake.

So through all of these, our main four objectives are: 1- to warn the driver if the ATF 21 temperature passes 79.5°C. 2- Warn the driver after a period of time (10 s) if he kept applying brake pedal at stationary while the engine 24 is at idle and the transmission shift lever 23 is put at drive. 3- To actuate the auxiliary fan 33 and the thermostat 34 when the temperature of the ATF 21 is rising up over limits to provide a cooler condition from the engine 24 which is affecting by its lowered heat the surrounding area of the transmission 20. 4- Warn the driver about the remaining mileage to replace the ATF 21.

To go a further step in arranging the warning system 26 operation, a flow chart need to be drawn at first, wherein the flow chart will show how the information will flow to achieve the four objectives mentioned in the prior paragraph. Fig. 1 is showing a flow chart, note that after receiving the following data: ATF 21 temperature from ATF temperature sensor 27, transmission shift lever position 23 from its sensor 28, vehicle speed from the vehicle speed sensor 29 wherein all of these are extracted from the transmission (gear) electronic control unit 38. Getting wheels speed from ABS speed sensors 30 that feed data to the ABS control unit 39. And getting from the engine electronic control unit 40 the engine speed from the engine speed sensor 31, coolant temperature from the coolant temperature sensor 32, auxiliary fan 33 speed, and thermostat 34 opening position from the engine control unit 3. These data are processed in the microprocessor 35, wherein the actuation of the messages will be divided into two parts:

The first part: if the ATF 21 temperature >79.5°C, due to towing, climbing mountains, stuck wheels in the sand, cooling system 22 overheating... the issued message by the instrument cluster 36 will be: "ATF overheats stop vehicle" with one warning (beeb) sound, obeying this warning message by the driver will decrease the ATF 21 temperature, and hence protecting it from overheating. Meanwhile if the thermostat 34 is closed and the auxiliary fan 33 is not working, they will be actuated to help in cooling the engine 24 and its coolant, that is because the engine's 24 heat affects the transmission 20 surrounding area, while the coolant temperature affects the ATF 21 temperature and ATF 21 cooling unit (heat exchanger).

The second part: if all sensors indicated that the transmission shift lever 23 is at drive position, and the engine 24 is running at idle (500-1300 RPM), and the vehicle speed = 0, the issued message by the instrument cluster 36 will be: "Move vehicle or shift to N" with one warning (beeb) sound, which means the driver has two choices, the first choice is to shift the transmission selector lever 23 to Neutral, wherein the message will be deleted, and the transmission's 20 torque converter 25 will be stopped, and hence no churning of the ATF 23 will happen, and so no heat build up will continue.

While the second choice for the driver is to move the vehicle so that the ATF 21 that is churning inside the torque converter 25, will have chance to move through the transmission 20, cooling pipes and cooling unit, wherein with the movement of the vehicle the outside air will move towards the parts in which the ATF 21 is contained and moving, and as a result the ATF 21 will be cooled down.

The flow chart also shows that every time a warning message is issued in relation to the ATF 21 temperature, these data are furthermore processed by a built-in program inside the microprocessor 35, to restimate or recalculate the remaining mileage (life) of the ATF 21, with an updating to the driver is carried out via a reminder message issued on the instrument cluster 36.

Figure 2 is showing the control system 26 flow of data from specific sensors toward their specific electronic control units, which provide these data to the microprocessor 35, which by its role manipulate the data and actuate the instruments cluster 36 to issue message and warning sounds.

Note that further conventional figures or drawings of the conventional available parts and wiring connections in-between them can be done by any person with little skills in the art, so it is excluded here.

Industrial applicability

The subject invention has the following benefits:

1- The sensors, actuators and instrument cluster to be used in the warning system are already available in any new vehicle.

2- The microprocessor and its programming can be made simply by any skilled body like any other conventional microprocessor available in any new vehicle. 3- The come outs of adopting such a warning system can calculates in billions of $ savings yearly, not only from the cash saving of decreasing the ratio of yearly repairs, overhauling or replacement of transmissions, but from the environmental saving of scrapping the replaced parts, and the transmissions fluids wastes.

4- Lowering the number of times of transmission fluid overheating, will participate even in a minor ratio in decreasing the warming potential of the Earth. 5-A comprehensive warning system that protects the ATF from overheating, or the transmission from running with a defected ATF, that is achieved either by protecting the fluid from overheating via the driver, or the engine cooling system side effects, or by protecting the transmission itself from an overheated ATF by recommending the driver to replace it at a knowledgeable known mileage instead of wrongly believing it is a long life fluid under whatever conditions.

5- in total such a system will lead to environmentally friendly results Parts Index:

20 Automatic transmission.

21 Automatic transmission fluid (ATF).

22 Cooling system.

23 Transmission shift lever.

24 Engine.

25 Torque converter.

26 ATF Warning System.

27 ATF temperature sensor.

28 Transmission shift lever position sensor.

29 Vehicle speed sensor.

30 ABS wheels speed sensors.

31 Engine speed sensor.

32 Coolant temperature sensor.

33 Auxiliary fan.

34 Coolant thermostat.

35 Microprocessor.

36 Instrument cluster.

37 Information center.

38 Transmission electronic control unit.

39 ABS electronic control unit.

40 Engine electronic control unit.

Claims

1- An automobile transmission (20) warning system (26) for protecting ATF (21 ) and automatic transmission (20) mainly from overheating at transmission shift lever (23) drive position with vehicle speed = 0, primarily via warning messages, warning sounds, and secondly via engine (24) cooling system activation, the system is comprising: a specific microprocessor (35) with a specific built in program; a set of available sensors in vehicles, providing data to vehicle ECUs (38, 39, 40) such as: ATF temperature sensor (27), transmission shift lever position sensor (28), vehicle speed sensor (29), ABS wheel speed sensors (30), engine speed sensor (31), coolant temperature sensor (32).

Transmission electronic control unit (38);

ABS electronic control unit (39);

Engine control unit (40); Instrument cluster (36);

Information (messages) center (37); auxiliary fan (33); coolant thermostat (34);

2- The ATF (21) temperature warning system (26) in claim 1 , wherein the specific microprocessor (35) is installed in the vehicles to manipulate the data received from the gear control unit (38) that is received from the ATF temperature sensor (27), and the transmission shift lever position sensor (28), and vehicle speed sensor (29). And to manipulate the data received from the engine control unit (40) received from the engine speed sensor (31), coolant temperature sensor (32), auxiliary fan (33), and thermostat (34). And to manipulate the data received from the ABS control unit (39) that receives the data from the wheel speed sensors (30). 3- The microprocessor (35) in claims 1 and 2, wherein the manipulated data via it, are used to issue messages, create warning intermittent beeb sound, via the instrument cluster (36), or to activate the auxiliary fan (33) and coolant thermostat (34). 4-The ATF (21) temperature warning system (26) in claim 1, wherein if according to the engine speed sensor (31) data that are showing that the engine (24) is running at idle and the transmission shift lever position sensor (28) is showing that the lever (23) is at drive position, and the vehicle speed sensor (29) and the wheel speed sensors (30) are showing that the vehicle speed = 0, a warning message after time delays 10 s is issued to the driver: "Move vehicle or shift to D" with one warning (beeb) sound, while after a time delay of 15 s the (beeb) sound is kept as continuous intermittent (beebs).

5- The ATF (21) temperature warning system (26) in claim 1, wherein if the ATF (21) temperature according to the ATF temperature sensor (27) is over the operating limit e.g ATF TEMP.≥ 79.5°C, a warning message is issued to the driver: "Stop vehicle" with one warning (beeb) sound.

6- The ATF (21) temperature warning system (26) in claim 1, wherein if the ATF (21) temperature according to the ATF temperature sensor (27) is over the operating limit e.g ATF TEMP. > 79.5°C, the engine (24) cooling auxiliary fan (33) and coolant thermostat (34) are actuated.

7- The microprocessor (35) in claims 1 and 2, wherein it will store and manipulate all stored and received data after a warning message is issued, to recalculate the remaining mileage for replacing the ATF (21) via a warning message updating the driver about it.