GB2206646A - Engine valve gear - Google Patents

Abstract

Mechanically, electrically, hydraulically or pneumatically operated valves are controlled electrically. A computer may control the valve actuators and additionally ignition, fuel injection and the transmission gearing.

Description

Improvements in valve actuation for Heat Engines.

RNTRODUCTION.

This invention relates to all reciprocating heat engines other than turbines whether diesel, petr:rl, steam, sterling or other types.

On these engines the phases of the operating cycle are controlled either by fixed ports interacting with pistons, or by valves of various types.

Typically these valves may be of poppet, sleeve, rotary, double beat, or slide type.

Valves on engines are all currently actuated by mechanical means, such as cams and springs, desmossromic cam systems, eccentrics, or linkages or any combination of these.

The mechanical complications of these systems is considerable and this becanes excessively so when variation in valve timing is attempted.

The noise generated by mechanical actuating equipment is also a considerable disadvantage.

There is a need for simplification in the valve actuation of all heat engines, particularly in automobiles. This new system should also faciliate variable valve actuation relative to crank angle, and variable opening interval and possibly variable valve lift to permit optimisation of engine performance against parameters of maximum performance, maximum economy, maximum smoothies, minimum noise, or maximum power time lif product.

OBJECT OF THE INVENTION.

The object of this invention is to replace current valve actuation means by an electrically controlled actuator operating on each individual valve or group of valves.

STATEMENT OF INVENTION.

According to the present invention there is provided an engine having one, or more valves to control its operating cycle.

The operation of these valves to the required extent and in the required order is controlled by electrical signals, supplied to the actuators, which depending on the signals actuate the valves by mechanical, electrical, hydraulic, or pneumatic power.

As a result of this change the gear trains and camshafts previously required may be eliminated and replaced in its most elementary form by a simple switching device.

This reduces cost of the engine, and also reduces noise levels intrinsic to the engine design. It is also feasible with this design to control valve actuation by computor, allowing adjustment fran cycle to cycle to achieve optimum performance, or optimum economy, or minimum noise, or minimum vibration, or other parameter.

Anti-knock provision of a petrol engine can also be made by simple adjustment to the ccmputer programmed information.

The same computer may also control the fuel injection into such engines, and in some cases the transmission also faciliating total management of the entire drive line to achieve optimum results overall against any specific parameter.

DRAWINGS.

Figure 1 is a cross section of a typical poppet valve in a petrol engine for use in a passenger car constructed in accordance with this invention.

Figure 2 is a double beat valve suitable for controlling the cycle of a steam engine constructed in accordance with this invention.

SPECIFIC DESCRIPTION.

Refering to figure 1 the poppet valve 1 and its associated guide 2 are manufactured in accordance with currently understood technology.

The valve is considerably shorter than normal and attached to its stem is a hydraulic actuator 3. The example shown is adapted to hydraulicaly open and close the valve. An alternative cheaper solution would be to use a spring closed valve which is only opened by the actuator, but this will restrict engine speed.

The actuator and valve stem are firmly joined by a collet type connector.

Control of the hydraulic actuator is by spring returned solenoid operated piston valve 4, which is connected to a hydraulic pressure supply line 5 and a return line 6 to supply tank.

Other types of electrical control are feasible, such as poppet valves, and valves requiring signals for movement in either direction.

The actuator is attached to the engine structure by a mounting with lateral compliance but negligable longitudinal ccmplience relative to the actuator.

The method of operation of this design is simply that when the valve is to be opened, the solenoid is energised.

The signal may cane frail a simple switch on the ignition distributor drive. Alternatively various degrees of sophistication in control are feasible, the most advanced is likely to be a system which selects and autanaticaly controls the valve timing and opening, together with the ignition and fuel injection functions and with the ratios of a computer controlled gearbox to give any one of the followingoptional optimisation targets.

1. Maximum performance.

2. Maximum econamy, by varying timing or cutting out operation of sane cylinders.

3. Minimum noise in vehicle.

4. Minimum external noise.

5. Most canfortable ride.

6. Minimum noxious emmissions.

7. Maximum durability.

Any of which can be selected by the driver while driving.

In addition an input into the controlling canputer when the brakes are applied may then adjust the valve timing to achieve maximum engine braking. Any combination or all of these features may be programmed into the engine/trasmission management system.

The principle as set out here can be used for valves of other engines, not necessarily of internal combustion types.

Figure 2 illustrates a steam engine double beat valve. The valve 1 running in a guide is connected directly to an actuator 3 which is controlled by a solenoid operated piston valve 4 with its hydraulic supply 5 and return line 6.

This valve may be controlled to vary expansion ratio, steam wetness at exhaust, or forward braking, and reverse running, all under simple switched control, or by computer control of various levels of sophistication.

Claims (6)

CLEMS .

1. A heat engine in which the phases of the operating cycle are operated by valves, such valves being opened by electrically controlled actuators and closed by spring means.

2. A heat engine as described in (1) above the valves of which are opened and closed by electrically controlled actuators.

3. A heat engine as described in (1) and (2) above wherein the movement of the valves is measured and signalled by transducer devices.

4. A heat engine as described in (3) above wherin the timing of the valves is varied by suitable electrical or electronic means to achieve approximation to the optimisation of certain operating parameters of driving and braking, or other operation.

5. A heat engine as described in (3) above wherin the opening distance and the timing of the valves is varied by suitable electrical or electronic means which may ellimiate the operation of certain cylinders if necessary, to achieve approximations to the optimisation of certain parameters of driving or braking.

6. A heat engine as described in any previous claim, where provision is made to select different bases for optimisation of performance.