EP0082837A1

EP0082837A1 - Microprocessor controlled variable capacity internal combustion engine

Info

Publication number: EP0082837A1
Application number: EP19810900214
Authority: EP
Inventors: Norman Stinson Ritchie
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-01-21
Filing date: 1981-01-21
Publication date: 1983-07-06
Also published as: WO1982002576A1; AU6707281A

Abstract

Un moteur a combustion interne avec un rapport de compression variable a l'aide d'une tete de piston ajustable. Les tetes de piston sont reglables le long de leurs axes longitudinaux, de maniere a augmenter ou diminuer le volume de la chambre de combustion. Un microprocesseur est utilise pour etablir la liaison entre le systeme d'injection de combustible et le turbo-compresseur, ou alternativement le circuit pneumatique pour obtenir la compression optimale dans la chambre de combustion pour tout reglage de capacite, pour le combustible particulier utilise, que se soit du diese1, de l'essence, du gaz propane, ou de l'alcool, ou tout autre carburant de propulsion. L'invention explique comment les resultats obtenus a partir du fonctionnement au banc d'essai ont pu etre utilises pour cabler le microprocesseur de maniere a obtenir le rendement maximum du combustible pour des conditions de conduite variables. Dans le cas de vehicules de marchandises lourds, cela peut inclure une conduite du vehicule decharge, ou de conduites sur autoroute. Le microprocesseur possede un clavier d'entree a touches, ainsi qu'une unite d'affichage visuelle LED, et il peut etre utilise pour controler le rendement du moteur, ainsi que pour gerer les parametres variables de capacite.An internal combustion engine with a variable compression ratio using an adjustable piston head. The piston heads are adjustable along their longitudinal axes, so as to increase or decrease the volume of the combustion chamber. A microprocessor is used to establish the connection between the fuel injection system and the turbo-compressor, or alternatively the pneumatic circuit to obtain optimal compression in the combustion chamber for any adjustment of capacity, for the particular fuel used, that be diese1, gasoline, propane gas, or alcohol, or any other propellant fuel. The invention explains how the results obtained from operation on the test bench could be used to wire the microprocessor so as to obtain the maximum fuel efficiency for variable driving conditions. In the case of heavy goods vehicles, this may include driving the unloaded vehicle, or driving on the motorway. The microprocessor has an input keypad, as well as a visual LED display unit, and it can be used to monitor motor performance, as well as to manage variable capacity parameters.

Description

MICROPROCESSOR CONTROLLED VARIABLE CAPACITY INTERNAL COMBUSTION ENGINE

I, NORMAN STINSON RITCHIE, a British subject of 17 Thirlmere Road, Patchway, Bristol, BS12 5PD), in the County of Avon, England, do hereby declare that the invention for which I pray that a patent be granted, tinder the Patent Cooperation Treaty, and the method by which it is to be performed to be particularly described in and by the following statement :-

This invention relates to internal combustion engines, and in particular to the improved efficiency in the use of fuels in a variable capacity combustion chamber.

It is known to adjust the volume of the combustion chamber whilst the compression ratio is kept constant by a turbo compressor charger, or as an alternative a pneumatic circuit incorporating a twin head horizontally opposed diaphragm type compressor, in addition to a fuel injector circuit. The engine capacity and the compression ratio are synchronized by the microprocessor. Yet another object of this invention is to provide an adjustable piston head which can be actuated sufficiently accurately and rapidly with very precise control at top dead centre position of the piston head.

The scope of the invention is defined bj the appended claims; and how it can be carried out will be apparent from the following description and accompanying drawings wherin :-

Fig; 1 is a longitudinal section of the cylinder head and cylinder embodying the invention;

Fig; 2 shows an electric brake gearmotor with off-set gearbox, and chain drives with sprocket wheels. Fig; 3 shows a Turbo Compressor charger circuit, and fuel injection system.

Fig; (1) comprises a stainless steel splined rod 4 screwed into a rotatable piston head 7, which is locked in position with a thread key and thermo-setting glue. The opposite end moves up and down within a female socket 3, in which a keyway is formed. The socket 3 is fixed to the inner race of a call bearing 6 and is held in position by a boss 5, which is screwed into the cylinder head 10 onto a thrust washer which is located at the bottom, of the threads, effectively sealing the cylinder but allowing the socket to rotate, clockwise or anticlockwise. A chain sprocket wheel 2, is fixed to the socket. The piston head 7 is screwed to the piston body 8, and helical coil thread inserts 12 of the free running type are interposed between the tapped and screwed threads to reduce wear and provide good turning qualities.

Fig; (2) shows a 12 volts Prake gearmotor with an off-set gearbox 13, and a double chain sprocket wheels 14, for mounting on the side of the engine. At rest the motor is braked, but when energized the brakes are released. The motor operates in two senses, clockwise or anti-clockwise. The gearbox contains reduction gearing giving low R.P.K. output for accurate location and high torque for turning the piston heads. The electric gearmotor is controlled by the microprocessor which records the height of the piston heads, stops the motor and stores the information. This is achieved by a sensor on the lowest turning gear wheel. More than one sensor on the gear wheel will give very precise location of the heights of the piston heads.One electric gearmotor will be powerful enough to rotate all piston heads even whilst the engine is running

Fig; 3 shows the Turbo Compressor Charger circuit to which tte following reference numbers apply:-

17 Air intake and Turbo Compressor 18. Air inlet Kanifold

19. Air temperature circuit

20. Air flow pressure regulator. 21. Throttle switch.

22. Cold start injector. 23. Auxiliary air valve. 24. Fuel injector.

25. Fuel pump.

26. Fuel filter.

27. Fuel pressure regulator.

28. Fuel regulator pipe.

29. Ring gear.

30. Thermo time switch.

31. Temperature sensor.

32. Compression pressure sensor.

33. Rotational speed sensor.

34. Reference mark sensor.

35. Microprocessor with input facility, and L.E.D. display unit.

36. Turbo compressor rotational speed regulator. ( For small engines only)

37. Ignition switch.

38. Ignition coil for spark ignition engines only.

39. Distributor for spark ignition engines only.

40. Electric brake gearmotor.

41. Piston head positional sensor.

42. Gear ratio engagement sensor.

An alternative means of supplying air with an adjustable pressure to suit the capacity setting would be the use of a twin head horizontally opposed diaphragm type compressor, driven by the engine and initially supplying a small air receiver vessel via a non return valve. From the air receiver it would be fed through adjustable pressure reducing valves actuated by the microprocessor and injected into each cylinder at pressures to suit the capacity setting. Thus for any capacity setting the compressed air/fuel pressure could be kept constant. The microprocessor would interface with the air/fuel injectors, as well as pressure/capacity settings for optimum fuel efficiency. Such a system would operate as a closed circuit not open to atmospheric pressure. By charging the cylinders at, or nearly at top dead centre position on the compression stroke would compensate for the power loss required to run the compressor. However for a low pressure system the cylinders would require charging approximately at the half way mark between bottom and top dead centre position so that final compression would take place in the cylinders.

She function of a microprocessor is to interface and synchronize all the engine running variables, and issue control signals to the various control valves and meters, as well as store in its memory such parameters as engine capacity setting, fuel octane number, and whether spark or compression ignition. In the case of heavy goods vehicles of the 7.0 litres variety, it would also store in its memory whether laden or unladen, and the processor would in addition interface between gear ratio engaged and capacity setting. It can be shown that for maximum efficiency in fuel consumption such engines must operate within a narrow band of revs. With an adjustable capacity engine fewer gear ratios would be required since control of the torque would be by way of the said invention, and sot solely dependent on gear ratios. Accordingly the microprocessor would be programmed to increase the capacity setting for any sudden requirements for increased torque related to the gear ratio in use.

The input facility would comprise a touch button keyboard, for the following information :-

Fuel Octane number

Spark or compression igrition Motoring condition such as motorway constant speed, or other types. Laden or unladen in the case of heavy goods vehicles. Wind speed in the case of light vehicles. Such a facility would require a display unit in the form of a L.E.D. (light emitting diode) which would show at a glance the selected parameters, and programme mode in which the engine was running. It could also display the speed of the vehicle; engine torque; R.P.M; engine temperature, and fuel left in tank.

Another feature which could be incorporated into the microprocessor would be a colour change in the revolution counter digits, whenever a gear change was recommended. For fuel efficient low revving high torque heavy goods vehicle diesel engines, the relatively narrow usable rev band from 1,300 to 1,000 R.P.M. the colour code for the digits would be green. Outside this band the colour code would be red, the point at which gear changes can be made, encouraging the vehicle to be driven at a steady pace. With such engines the inventor envisages cutting the number of gearbox speeds down to four, or five, and using the variable torque characteristics of the engine to provide the difference, for smooth running, and efficiency in fuel consumption. The use o fewer constant mesh gears would reduce the amount of power required to drive the gears, and this factor would be important when driving the vehicle especially in the unladen state when the engine capacity would be adjusted to its lower ratings.

The fuel injection system differs from existing electronically controlled injection systems in that the air inlet pressure is also controlled by a microprocessor for optimum efficiency in the use of fuel of any octane number, as prescribed by the oil company, and would allow for engine temperature variations, in addition to the most important factor, namely the engine capacity setting. Rapid calculations would be performed by the processor, and the engine compression continually updated, and checked for efficient fuel consumption. By engine compression is meant the pressure of the compressed fuel/air mixture at top dead centre position immediately prior to the explosion stroke. Tne stroke length of such an engine would remain constant, and therefore it is important to maintain control over the air charging pressure, if full advantage is to be taken of the variable capacity characteristics of the engine. For this reason a Turbo compressor charger whilst relying on the engine speed for its own rotational speed, requires a fan that can deliver air at pressure, which can be adjusted, if necessary by a reduction valve. Such a Turbo charger exists which employs a mixed flow fan. A mixed flow fan as its name implies is a cross between an axial flow type, and a centrifugal impellor type. Automotive fans used for cooling are of the axial flow type, but are limited in performance try the speed of the engine, whilst centrifugal is capable of delivering at high pressure but because of its size is not used in automotive designs. Suitable mixed flow fans would require design to suit aiy particular engine rating. Tne nominal rating is defined in the context of this invention as the mean capacity of the engine which occurs when the piston heads have reached two thirds of their forward threaded travel, since one third of the threads are required for securing the piston head to its body in the minimum capacity position.

For the design of the engine to function satisfactorily, it would mean that in this position known as manual override, the engine would not require microprocessor supervision, and therefore should the microprocessor break down the driver would have the option of continuing without it. A touch button would be provided on the keyboard, for this purpose. By pressing this button the brake gearmotor would return the engine to nominal capacity rating.

CARRYING OUT INVENTION

After a number of test experiments on a test bed rig, the results of R.P.M/torque/capacity/fuel consumption, would enable the manufacturer to recommend combustion chamber settings to suit various motoring conditions, such as cruising on the motorway, laden or unladen especially in the case of heavy goods vehicles, traffic crawls, climbing hills, decending hills, accelerating from a stationary position, though in the case of heavy goods this would be automatically performed by the gear changes, as indeed similar consideration could be given to lighter vehicles.

The stainless steel rod shown in Fig; (1) would be made of Inconel, or other high alloy steel, which retains its tensile strength at elevated temperatures. It is important that the rod diameter be kept as small as practicable so as to cause as little obstruction as possible within the combustion chamber, and its weight to a minimum, as well as make the seals simple and effective. Another consideration at this stage is the use of a hollow rod with horizontal aperture holes for speedy evacuation of the socket during the compression stroke, as well as other additions or alternatives considered to improve the efficiency of the invention. Clearances for a running fit between the rod and the socket would allow for cylinder wear, and some form of lubrication would be considered, possibly a Teflon liner in the socket and/ or on the rod, to ensure long and trouble free life. Other possible improvements in the performance of the invention would be some forced lubrication of the piston head thread inserts by means of oil jets from the cylinder walls, whilst the piston is in the bottom dead centre position.

After completion of engine tests, electronic controls would be added. The results would be used for hard wiring the microprocessor for onboard use in the vehicle, and the programmes designed for optimum fuel efficiency.

Finally it must be pointed out that the splined red which moves within the socket must be of such length that part of it remains within the socket during a complete cyile of the engine, and the height of the socket be such that the piston head can never be accidentally unscrewed from the piston body.

Claims

What I claim is : -

1. An internal combustion engine comprising cylinders and pistons having piston heads adjustable along the longitudinal axis thereof, so as to increase or decrease, the volume of the combustion chamber.

2. An internal combustion engine according to Claim 1, in which the engine compression pressure is adjusted and maintained by means of a turbo compressor charger or alternatively by means of a pneumatic circuit.

3. An internal combustion engine according to Claims 1 and 2, in which a microprocessor interfaces between the selected capacity setting and engine compression pressure, and adjusts the air charge pressure, so that the compression pressure remains constant for any adjusted engine capacity.

4. An internal, combustion engine according to Claim 1, in which the said piston heads are screwed to the piston bodies, with helical coil thread inserts interposed between the threads. The said piston heads are thus adjustable along the longitudinal axis thereof, which is effected by means a of/splined rod fixed to the said piston head. During engine rotation the splined rod moves vertically up and down, remaining partly within a socket with mating keyway and rotatable bearing5. An internal combustion engine according to Claim 4, in which a socket rotated by a chain sprocket wheel, is held in position and sealed by a screwed boss, ball bearing race, and thrust washer, which allows the socket to rotate but prevents any escape of gas. 6. An internal combustion engine according to Claim 5, in which an electric brake gearmotor equipped with sprocket wheels and chain drives, rotates the complete engine assemblies, (one assembly per cylinder) concurrently, and whilst the engine is running, so that each cylinder is adjusted by exactly the same amount, in terms of cubic capacity by each revolution, or part thereof, at any instant in time.

7. An internal combustion engine according to Claims 2, 3, and 6, in which the said assemblies are rotated accurately, and with very precise control of the engine compression, in which the said brake gearmotor locks the adjusted assemblies in position by means of its spring operated disc brakes, which act instantly on de-energizing the electric brake gearmotor. 8. An internal combustion engine according to Claims (1 - 7) inclusive, in which a microprocessor is programmed to select the most efficient power rating for any particular motoring conditions. 9. An internal combustion engine according to Claims (1 - 8) inclusive in which a microprocessor is programmed to select an optimum capacity in relation to the gear ratio engaged, and in the case of heavy goods vehicles, with respect to whether laden, or unladen.

10. An internal combustion engine according to Claims (1 - 9) inclusive in which a programmable microprocessor synchronizes the adjusted engine capacity, and the engine compression, to suit any particular fuel octane number, including any variety of petrol, gas, alcohol, or diesel oil, the microprocessor having touch button input facility for such constants, and L.E.D; (light emitting diode) display unit, for visual verification.

11. An internal combustion engine according to Claim 10, in which the microprocessor is provided with a Manual Override touch button. In the said position the electric brake gearmotor returns the engine capacity to the nominal capacity rating, in which position the engine functions without the aid of the microprocessor.

12. A fuel efficient variable capacity, spark, or compression ignition, internal combustion engine, with microprocessor engine control, substantially as hereinbefore described, and as illustrated in the accompanying drawings.