WO1999047794A1

WO1999047794A1 - Selective disabling of cam operated devices

Info

Publication number: WO1999047794A1
Application number: PCT/IN1999/000008
Authority: WO
Inventors: Vasant Joshi
Original assignee: Vasant Joshi
Priority date: 1998-03-16
Filing date: 1999-03-15
Publication date: 1999-09-23
Also published as: EP1062410A1; AU3626299A; KR20010041904A; JP2002506948A

Abstract

Each cylinder valve (14, 15) of an internal combustion engine is intermittently and cyclically operated in active mode by a cam (3a, 3b), acting through a cam follower (4a, 4b). Cyclic operations of the valve (14, 15) are suspended throughout passive mode of the cylinder. The cam (3a, 3b) operating the valve (14, 15) has uniform radial profile excepting for a lobe and a trough. In active mode, the lobe of cam lifts the cam follower (4a, 4b) to open the valve (14, 15) while trough of cam (3a, 3b) passes under the cam follower (4a, 4b) without affecting the closed valve. Changes in operating mode of a valve (14, 15) involve reconfiguring mode changing components comprising the cam follower (4a, 4b), necessitating entry of cam follower (4a, 4b) in the trough of cam profile during an intermediate phase, to maintain the timing. Although all valves of a cylinder change to same mode by common initiation and motive power, troughs of operating cams time mode changes of individual valves.

Description

SELECTIVE DISABLING OF CAM OPERATED DEVICES

TECHNICAL FIELD

The invention allows selective^" control of periodic cam operations of devices such as cylinder valves of internal combustion engines. Its primary application relates to selective and synchronous suspension and resumption of cylinder valve operations in fuel-efficient engines.

BACKGROUND ART

Indian Patent App. No. 60/BOM/97 and US Patent Application No. 09/076,643, have described internal combustion engines in which operations of cylinder valves are selectively, enabled or disabled, depending on load and other considerations. Controlled variable number of cycles operating in active mode produce desired power output, while other cylinders in passive mode are not charged and produce no output. Mode cams rotating at integer fraction of camshaft speed power and time the suspensions and resumption of valve operations. Although the improved engine is more fuel-efficiency and less polluting than a conventional engine, the larger size, increased cost and complexity of the mode changing mechanisms become deterrents in practical applications of the invention.

DISCLOSURE OF INVENTION

The present invention allows easy, direct changes in operating modes of individual cylinders of an engine. Changes in mode of suction and exhaust valves of a cylinder are automatically synchronized with periods of closure of respective valves, in the cycle. There are different provisions for powering and timing the mode changes. Internal or external means initiate changes in operating mode of a cylinder by asynchronously providing power for changing mode of the cylinder valves. However, the power is utilized for reconfiguring mode-changing components of each cylinder according to the timing provided by the cams that operate the respective valves.

In preferred embodiments of the invention, each cam profile has a trough in definite rotary position relative to the lobe. In active mode configuration of mode changing components, the cam follower is lifted over the lobe for opening the valve. However, passage of trough of the cam under the cam follower has no effect on cam follower or the valve, which remains closed. In passive mode configuration of mode changing components, the cam follower is temporarily retracted or relieved from the cam to suspend cyclic operations of the valve. Mode changing components including ^"cam roflower reconfigure with mdc-e-selective pressure, necessitating the cam follower to temporarily enter within the trough of cam profile in transient dispositions. This times the change in operating mode of each valve with the incidence of its cam follower over the trough of operating cam.

Most internal combustion engines have multiple cylinders. The mechanism of present invention is ideally suited for changing mode of individual cylinders. Mode changes of cylinders are staggered over the range of accelerator pedal positions to have more cylinders in active mode over longer periods for lower accelerator positions. Activation of additional cylinders is resorted to only after cylinders those are already active generate close to peak power. Likewise, lifting of accelerator pedal deactivates one or more cylinders, whenever fewer cylinders in active mode are found adequate to service lighter loads. If one or more cylinders remain active during change of mode of other cylinder or cylinders, the former cylinders adjust their output to compensate for quantum changes in power output by change of mode of latter cylinders. The above method of power control gives jerk-free and generally proportional power output to accelerator position.

Without precluding and limiting other interpretations, the description refers to three generic types of mode changing mechanisms, for cylinder valves of internal combustion engines. Each mode changing mechanism suits certain type of valve opening means. The first type of mode changing mechanism suits valve-opening means, comprising a cam follower that connects to both valve and cam. A. Operating mode of a valve is changed to passive or active mode, by transporting a movable carrier carrying the cam follower away from, or towards, either of valve and cam, respectively.

The second type of mode changing mechanism suits valve-opening means comprising' of a cam follower and a distinct lever joining the valve. Different carriers carry each of lever and cam follower. Either of the carriers is moved away from, or towards, one of valve and cam for changing operating mode of the valve to passive or active mode, respectively. The third type of mode changing mechanism suits valve-opening means, which open the valve in active mode by transferring motion induced. by the cam through a cam follower, latch and lever, in that order. A carrier fixed to the engine body supports lever and cam follower. A movable carrier moves ^"trie latch -©'""different dispositions between lever and cam follower, in active and passive modes. In active mode, the position of latch between cam follower and lever, efficiently transfers cam induced movement of cam follower to the lever to cause valve operations. In passive mode, the retracted latch between cam follower and lever fails to transfer the motion from cam follower to lever, making the valve inoperative by the cam.

The invention is now described with help of figures and tables. Unless otherwise mentioned, text and drawings refer to a spark-ignited multiple point externally fuel injected automobile engine with single overhead camshaft, three in-line cylinders, two valves per cylinder, and a four-stroke working cycle. Unless repugnant to context, net power output of engine is equal to load demand, and the engine is assumed to run at constant speed.

BRIEF DESCRIPTION OF DRAWINGS

The following reference signs are used in the description and drawings:

Body 1, camshaft 2, cams 3, rocker 4, shaft 5, links bracket 6, sidebars 7, accelerator pedal 8, accelerator cable 9, accelerator spring 10, mode selector 11, locator 12, rocker pivot 13, suction valve 14, exhaust valve 15, valve spring 16, mode spring 17, lock 18, spring 19, throttle valve 20, handlebar 21, accelerator handle 22, rotary holder 23, retainer 24, pin 25, pin 26, follower 27, lever 28, latch 29, cable 30, rocker spring 31, spring 32, stopper 33, ledge 34, links 35, fuel controller 36, actuator 37, air flow meters 38, bearing 39, drum segment 40, link 41, constriction 42, pivot pin 43, solenoid actuated fuel injector 44, suction manifold 45, flow control valve 46, direction control valve 47, rotary encoder/speed switch 48, compensator 49, fuel line 50, magnetic set screw 51, distributor 52, accumulator 53, thermostat 54, flow control valve 55.

The described first three embodiments use unitary rockers as cam followers and first type of mode changing mechanism. Figures 1 to 10 illustrate the first embodiment. Figures 1 1 and 12 show the second and third embodiments.

Figure 1 shows mode changing components . for one cylinder configured for passive operating mode.

Figure 2 shows reconfigured components for active operating mode.

Figure 3 shows exploded view of mode changing components for a cylinder.

Figure 4 shows the arrangement for controlling power output in a multi-cylinder engine by changing the level of charge and operating mode of individual cylinders.

Figure 5 plots the response of charge and output of individual cylinders to movement of accelerator pedal. The plots are explained in Table I.

Figure 6 shows two sets of plots showing timing and sequence of operations of mode changing components for a cylinder. Table II explains the lower set of twelve plots, pertaining to first embodiment. The upper set of three plots, pertaining to the second embodiment, illustrated in fig. 11, are presented in the same figure to highlight differences in operations of certain components between the two embodiments of the invention.

Figures 7, 8. 9 and 10 show physical configurations of ^■ mode-changing components in instances that are marked in figure 5, during the phase of change to active operating mode.

Figure 11 illustrates the second embodiment of the invention. The three pronged design of exhaust rocker keeps exhaust valve partly open throughout passive mode.

Figure 12 shows a third embodiment of the invention suitable for an engine having its camshaft over the rockers.

Figure 13 shows a fourth embodiment of the invention using the second type of cam follower mechanism. One carrier holding the lever is fixed to body, while other carrier carrying the cam follower moves to change operating mode. Figures 14 - 16 show mode changing components for suction and exhaust valves, in the fourth embodiment of the invention; in passive mode, an intermediate stage between active and passive modes, and active mode, respectively.

Figure 17 shows a fifth embodiment of invention deploying third type of mode changing mechanism.

Figures 18 and 19 show a sixth embodiment of the invention, employing third type of mode changing mechanism. A valve is operated by either of two cams in one each of active and passive operating modes.

Figure 20 shows a seventh embodiment of the invention, suitable for an engine having four valves per cylinder. A cam operates one valve in passive mode, and two in active mode.

Figure 21 shows a hand operated method for changing cylinder mode in a motorcycle or outboard engine.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode derives maximum benefits of fuel efficiency and clean emissions offered by the invention, by operating an engine having multiple cylinders with least number of cylinders in active mode, for each load. Throttling of charge and injected fuel are secondary means for infinitesimally controlling the power output of cylinders in active mode. Apart from the magnitude of load as judged by the accelerator position, overriding considerations of engine temperature and speed determine each cylinder mode.

The arrangement of Figure 4 gives smooth control of power output, by controlling cylinder modes and charging of cylinders in active mode. Pin 25 on vehicle body holds one end of accelerator spring 10, and rotable hydraulic cylinder called compensator 49. Accelerator spring 10 lifts pedal 8. Mating teeth of accelerator pedal and compensator cause latter to turn with former. The sheath of an accelerator cable 9, held between stopper 33 on vehicle chassis and engine body 1, carries the core joining the end of piston of compensator 49 to throttle valve 20. A cam on accelerator pedal operates direction control valves 47x and 47y. Both valves are activated in idling position of accelerator pedal, and are serially released by movement of accelerator pedal frqm idle position.

Lubricating oil, under" presStfre, έ diverted 'to accumulator 53 for powering the changes of cylinder modes. Constriction 58 limits the maximum diversion of oil from lubrication system. Accumulator holds enough oil for several cycles of operations of actuators and compensator. Thermostat 54 activates direction control valve 46 to use the oil for changing cylinder modes only after the engine is sufficiently warm after running with all cylinders in active mode by default. Tank ports of solenoid valves 47x, 47y, and 55, discharge oil to engine sump. Rotary encoder / speed switch 48 activates direction control valve 55 to prevent oil from solenoid valve 47x from reaching one of inputs to distributor 52 on way to one of actuators 37, at measured engine speed less than 120 % of idling speed. Direction control valve 47y controls oil flow to compensator 49 and remaining two actuators 37 through distributor 52. The inputs to distributor are periodically reassigned to different outputs, by internal timing. This cyclically changes the order of activation of physical cylinders for equalizing wear and internal temperatures in cylinder. All cylinders x, y and z operate in active mode by default, and each changes to passive mode operations only while its actuator 37 remains actuated.

Each branch of suction manifold 45 leading to each of the cylinders, has air flow meter 38. Fuel pumped by an external pump is carried by fuel line 50, to each injector 44. Fuel controller 36 energizes solenoids of fuel injectors 44 for controlled variable periods in each cycle, to inject the desired amount of fuel for each cylinder in active mode. Rotary encoder/speed switch 48 synchronizes timing of fuel injection with suction stroke.

All cylinders operate in passive mode, when accelerator pedal is lifted above level 'b', and if engine runs at more than 120% of its idling speed. These conditions indicate a lack of load on the engine, further allowing a presumption that the engine can draw power from the connected load to meet its own losses, as in descending or retarding vehicles. At lower engine speeds, this presumption is not valid and one cylinder of the engine is activated by deactivatibn of flow control valve 55, irrespective of accelerator position. For accelerator pedal positions below 'b', the same cylinder operates in active mode by relieving direction control valve 47x, by the accelerator pedal. Power generated by the sole active cylinder suffices for idle running of the engine, and even for servicing light external loads corresponding to accelerator positions above 'c'. Heavier loads, corresponding to other accelerator positions call for activation of all cylinders.

Figure 4 shows the relative geometry of compensator and^ccelerator cable in idling position 'a' of accelerator pedal. The piston of compensator moves at right angle to accelerator cable for changing between active and passive modes, which makes little or no difference to throttle position. However, the throttle valve increasingly opens more with the extended piston than the retracted piston with lowering of accelerator pedal, and opens fully in position c with the extended piston, to deliver full output of the sole active cylinder before activation of the remaining cylinders.

The engine idly runs faster with one active cylinder, as a single cylinder is typically charged by about one and half times than its level of charge along with other cylinders for same throttle opening and engine speed. Lower internal losses in passive mode cylinders aid the increase in idling speed. The cylinders in passive mode can also be activated on demand within two camshaft cycles; in which event they generate even more power at the higher idling speed than their generation at regular idling speed with all active cylinders. Due to combination of these factors, the engine stably idling with one active cylinder and consuming only half the fuel than with three active cylinders, provides a power reserve that is about 50 per cent higher than with three active cylinders. Lesser consumption of fuel also means lesser emissions of carbon di-oxide, and even lesser NOx emissions due to combustion of denser and ricer mixtures in active mode cylinders.

Table I describes plots of figure 5, which relate power output of engine and operating mode and charging of its cylinders to accelerator positions. For increasing load, the first cylinder is activated (plot 4) when accelerator pedal is lowered below position 'b'(plot 1). Power output of the first activated cylinder (plot 5) increases proportionally to throttle opening (plot 2) to nearly peak level when accelerator pedal lowers to position 'c'. Remaining two cylinders (plot 6) are simultaneously activated in accelerator position V, with sharp cutback in opening of throttle (plot 3) to generally equate net power output of the engine with three active cylinders to the output with one active cylinder for same accelerator position 'c' (plot 2 ). Beyond accelerator position c, the throttle valve again opens with the accelerator pedal to give equal increase in output of all cylinders (plots 5 and 7) till the engine delivers its rated output for the current speed, with a fully open throttle valve in the lowest accelerator pedal position.

With fall in load from peak level, lifting of accelerator pedal simultaneously deactivates two cylinders in accelerator^"pos- fo c (plot 6)^'and opens throttle valve (plot 3) to derive all power from one active cylinder (plot 5). Even this cylinder is deactivated above level b* of accelerator pedal (plot 4), and the engine runs by drawing power from the load. Lowest levels of plots 2, 5 and 7 signify power consumption by individual cylinders and engine, rather than power generation. Slight staggering in accelerator positions for activation and deactivation of cylinders, as between b and b*, and c and c*, are result of dead zones in operations of direction control valves. This usefully avoids any cylinder from too frequently changing modes about any accelerator position.

Figure 1 shows mode changing components of one cylinder configured for passive operating mode in midst of suction stroke. Figure 2 shows reconfiguration of mode changing components for active mode and same camshaft position.

Figure 3 shows an exploded view of mode changing components of one cylinder. Cylinder head of body 1 has walls rising between adjacent cylinders, and at each end. Coaxial bores in walls pass shaft 5. For and above each cylinder, shaft 5 supports independently rotable, axially interlocked locators 12a for suction valve and 12b for exhaust valve, placed between a pair of flanges of separately rotable mode selector 11. A beam joins flanges of suction locator over exhaust valve, while a similar beam joins flanges of exhaust locator over suction valve. Inner flanges of suction and exhaust locators have bosses touching each other around shaft 5, and short horizontal pegs facing each other over the bosses. Flanges of mode selector join by an overhead pin passing above suction and exhaust locators. Each locator carries helical mode spring 17 around its boss. The two ends of each mode spring terminate beyond either side of peg of its locator and the pin of mode selector. Part of the inner flange of each locator radially protrudes over and across the beam of other locator.

Sidebars 7, fixed to body 1 carry ledges 34 on either side of each cylinder. In passive mode, the protrusion of suction locator and beam of exhaust locator rest under the ledge over suction valve, as shown in figure 1. In active mode, the protrusion of exhaust locator and beam of

8 suction locator rest under the ledge over exhaust valve, as shown in figure 2. In each case, the beam restraints movement of the protrusion, to prevent moves of exhaust and suction locators from active and passive mode dispositions, respectively, before the other.

Sidebars 7 support locl-s lifmid coil springs^" 19 over the ledges 34. Nearly horizontal prong of lock 18 presses down against the locator by pressure of spring 19, and locates in axial ridge on the locators in active mode disposition of suction locator and passive mode disposition of exhaust locator. The locked locator is effectively stalled from moving out of its positions, till released by the lock. The mode selector releases a lock on reaching the end of its movement to either mode, to allow movement of one locator that is locked directly, and the other locator constrained from movement by the first locator.

Walls of cylinder head have grooves in radial direction of centre-line of shaft 5. Locators 12, by their rotation around shaft5, move rocker pivots 13 held by links brackets 6, within opposite grooves over each cylinder, to passive and active mode dispositions respectively. Figure 2 shows rocker pivots 13 and rockers 4 in active mode position. Figure 1 shows both distant from valve and camshaft in passive mode positions. Rocker pivot 13 and rocker 4 reach the lowest position relative to valve and camshaft for one intermediate rotary disposition of locator between active and passive dispositions, shown in case of suction locator in fig 9.

Magnetic set screws 51 keep rockers joined to underlying valves, while permitting adjustments to maintain a small clearance between the rocker and radial positions of cam other than lobe and trough. Lubricating oil is carried to rockers through shaft 5, locator 12, links bracket 6 and carrier 13.

Actuators 37 for changing cylinder modes are held by sidebar 7 over exhaust valves. Link 41 envelops pin of mode selector on one side and joins piston of actuator 37 on the other. Mode selector turns by linear movement of actuator in either direction, caπying with it one end of each mode spring on its leading side. The other ends of modes springs exert pressure on the pegs of locators, to follow the mode selector in direction of movement. However, till the mode selector reaches the end of its new disposition, one locator remains directly locked by a lock, while the other locator is held in place by the first locator. Before releasing either lock, the mode selector stresses each of the mode springs adequately for moving the locator with connected links bracket, rocker pivot and rocker to position of changed mode within 140 degrees of transitory cam positions when the cam follower is incident over the trough of the cam. This period lasts for about 10 milliseconds at engine speed of 4000 RPM. Suction and exhaust cams assume transitory positions within expansion and exhaust strokes, and suction and compression strokes, reSffectfvely. Transitory positions of both cams are staggered to prevent undesirable simultaneous movement of suction and exhaust locators from active mode disposition, causing disabling of exhaust valve of a cylinder charged earlier in the cycle by open suction valve.

Plots 2 and 3 of figure 6 show varying radii of suction and exhaust cams under respective cam followers, in different camshaft positions.

The stress in mode spring is relieved when the locator moves with the connected rocker pivot and rocker. The locator and rocker pivot can move through one intermediate disposition between active mode and passive mode dispositions, only by pushing the rocker lower towards either of valve and cam. Its end over the valve is unable to lower due to opposition of the stiff valve spring. However, the pressure of mode spring is quite adequate to lower the other end of rocker without any resistance from the cam during transitory cam positions of a cycle, when the cam follower is incident over the trough of cam profile.

Figure 6 plots the sequence of events characterizing each change of operating mode for a cylinder. The four strokes of each camshaft cycle are marked as 1 to 4. Table II explains the plots of figure 6:

At beginning of cycle A, accelerator pedal is fully pressed (plot 1 ) and the cylinder is in activate mode. Lifting of accelerator pedal increases throttling to reduce power output of the cylinder till accelerator pedal reaches the threshold level "c*' when the actuator (not shown) for the cylinder turns mode selector (plot 4) to passive mode disposition. Rotation of mode selector stresses both mode springs, before releasing lock 18a (plot 5). Each mode spring moves the connected one of suction and exhaust locators to passive mode dispositions (plots 6 and 8), when each of the cam followers enters the trough of the cam, in respective transitory positions (plots 2 and 3). Cyclic operations of both cylinder valves by cams cease from camshaft cycle C (plots 11 and 12).

10 The cylinder reverts to active mode operations by lowering accelerator pedal below lower threshold level (plot 1). In passive mode, the exhaust locator blocks movement of suction locator to active mode in transitory cam positions of cycle N. The exhaust locator moves to active mode disposition dur gHhe^first half of cycle O, and operations of exhaust valve are resumed from the exhaust stroke of the cycle. Suction valve operations are resumed from following cycle P. The cylinder operates in passive mode from cycles C to O.

OTHER MODES FOR CARRYING OUT THE INVENTION

The amount of fuel injection can be controlled without airflow meters, by estimating the airflow based on estimated volume of combustion air calculated by considering throttle valve position, engine speed, engine temperature and number of active cylinders. An embodiment of the invention uses an EPROM that is programmed with a look-up table, for controlling the amount of fuel injection in each active cylinder in each current cycle. Fuel is injected only in the branches of suction manifold leading to active mode cylinders. Even the throttle position and number of active cylinders can be determined by software, rather than hardware as shown in figure 4.

An engine equipped with a carburetor automatically controls the ratio of air and fuel. However mixing both before the entry to suction manifold creates problems fuel droplets and film enter the branches leading to passive mode cylinders in absence of combustion air. Nonreturn flap valves provision of in each branch, which closes in passive mode in absence of air draft, is an easy way of avoiding the problem. Conventional carburetor has an economizer that directly injects liquid fuel without atomizing in the air stream to each cylinder. Such flow has also to be eliminated whenever the cylinder is in passive mode.

Cylinders can contribute differently to power output than the first embodiment. In one variation of the first embodiment, specific cylinders receive charge through a manifold, which freely admits air without throttling. Each of these cylinders contributes full power output in active mode. Charge to one or more cylinders in active mode is however throttled, or quantity of fuel injected in these cylinders is varied, to produce finely variable component of net power output.

11 In another version of the invention, all cylinders of an engine receive charge without throttling, and fuel in ideal ratio for combustion, in every active mode cycle. Frequent switching of one or more cylinders between active and passive modes with a duty cycle responding to load variutions'-ι--elV^vv--rics power output of the engine.

Closure of suction and exhaust valves of a cylinder throughout passive mode creates conditions of partial vacuum in passive mode cylinders, allowing the piston rings to collapse within the grooves and cause least friction during reciprocal pistons movements. Optionally, the suction valve can be closed but exhaust valve opened to allow a cylinder to freely breathe the gases of exhaust manifold. Unhindered flow of gases through the exhaust valve avoids build up of pressure in the cylinders and allows free piston movement. The hot exhaust gases, initially generated by other active cylinders, transfer some heat to the passive mode cylinders and pistons, avoiding deformation of piston geometry and helping combustion in subsequent active cycles.

Figure 11 shows a second embodiment of the invention, which has a partially open exhaust valve throughout passive mode. Exhaust rocker 4b has a vertical extension reaching up to beam of suction locator. In active mode, the prong delays rotation of suction locator to passive mode disposition till removal of hindrance in last exhaust stroke in active mode, as shown in plot 6a of figure 6. In passive mode, the beam of suction locator gets under the prong of exhaust rocker to prevent complete closure of exhaust valve; as shown in plot 12a of figure 6. Plot 9a of figure 6 shows the position of suction rocker pivot. While changing back to active mode, movement of suction locator to active mode disposition, before last exhaust stroke in passive mode releases the exhaust rocker. Suction locator does not obstruct normal movements of exhaust rocker in active mode.

Figure 12 shows a third embodiment of the invention, for an engine with camshaft over the rockers, using the first type of mode changing mechanism. Suction and exhaust rockers are carried by rocker pivots 13 movable within vertical grooves of body 1 , Links brackets 6 join rocker pivots and locators. Rotation of mode selector in any one direction compresses both mode springs, inducing torque on connected locators. Rocker pivots rise to highest level only when troughs of cam profiles in transitory cam positions allow rise of rockers 4, for flipping

12 of locators through intermediate dispositions, between active and passive mode dispositions around shaft 5.

The second type of mode changing mechanism, illustrated in figure 13 to 16, describes a fourth embodiment of the inVentiδn that is suitable for valve opening means comprising of two oscillating parts. A fixed rocker pivot 13 supports lever 28 joining the valve, while opposite bosses in links bracket 6 support cam follower 27 over bearings 39. Links bracket 6 have oval slots in within the bosses passing rocker pivot 13, which guides the movement of the bosses along radial direction towards or away from shaft 5 by rotation of locator 12 between active and passive dispositions. The bosses are concentric to rocker pivot in active mode disposition of locator, as shown in figure 16; while they are raised from this position by link brackets for passive mode disposition of locator shown in figure 14, and lowered from this position for one intermediate disposition of locator between active and passive dispositions, as shown for the boss of links bracket for suction valve, on left of figure 15.

Pin 26 joins cam follower 27 and lever 28. In active mode configuration of figure 16, both cam follower 27 and lever 28 turn concentrically around rocker pivot 13, to operate as unitary rocker and open the valve by lobe of the cam. In passive mode configuration, the cam follower is clearly lifted off the cam lobe to eliminate valve operations by cam. However, for changing between modes, the locator has to assume an intermediate disposition between active and passive mode dispositions which is allowed by the cam follower entering the trough of cam profile in transitory cam positions, as shown for the suction cam follower in figure 15.

The fifth embodiment of the invention described in figure 14, uses the third type of mode changing mechanism for reconfiguring valve opening means comprising of three oscillatory parts. Cam follower 27 joining the cam, and lever 28 joining the valve, are two of the three oscillatory parts of valve opening means that are carried by fixed rocker pivot 13. A movable pivot pin 43, carried by links bracket 6 holds the third oscillatory part that is latch 29 on

/ bearings 39. Links bracket 6 moves pivot pin 43 by rotation of locator, within radial grooves of walls in body 1 in direction of shaft 5.

Cam follower 27 and lever 28 can independently oscillate around rocker pivot 13. Both have

13 facing surfaces with involute cam profiles on their top, joining matching profiles on sides of tooth at base of latch 29. The locator, in active mode disposition moves pivot pin 43 carrying the latch to correct center distance from rocker pivot 13, to introduce the right chordal thickness of latch between tooth forms of lever and cam follower. The gear-like enmeshing of latch with cam follower to l-fVer ogives smooth transfer of Oscillations from cam follower to lever through reverse oscillations of latch. The combined cam follower, latch and lever operate the valve by cam rotation, as any conventional rocker.

In passive mode disposition, pivot pin 43 lifts the latch to introduce less than chordal thickness of its tooth between tooth forms of lever and cam at the pitch circle of their involute profiles. The clearance between connecting profiles absorbs motion of the cam follower without transmitting it to the lever, resulting in a closed valve even for a cam follower lifted over the lobe of the cam lobe.

The locator turns between active and passive mode dispositions, only by wedging the latch deepest between cam follower and lever in one intermediate disposition of locator. For accommodating the greater chordal thickness of tooth of latch between lever and cam follower, the cam follower needs to enter the trough of cam profile by overcoming pressure of rocker spring 31 in transitory cam positions, which controls the timing of mode changes.

A sixth embodiment of the invention shown in figures 18 and 19 has a valve, alternately operated by different cams in different operating modes. Two flanges of the locator carry different links brackets around pins placed in staggered rotary positions around shaft 5. Each of the links bracket joins one of three links 57 by pivot pin 43. Rotation of locators causes movement of both pivot pins guided by one each of radial grooves in walls of body 1. One each of the two pivots pins is raised in either of active and passive mode dispositions of the locator, while the other pivot pin is lowered. Both pivot pins have to pass though their lowest levels in the grooves in slightly separated intermediate positions of the locator. The top link 57 joins other links 57 joining to each of lever and one of two cam followers, carried by each rocker pivot. In active and passive modes shown in figures 18 and 19 respectively, lowering of one connecting pivot pin 43 relative to the other, lowers one of the cam followers over its operating cam and lifts the other cam follower away from its operating cam. In this manner, one each of cams in each of operating modes operates the valve. Changes in operating mode

14 are possible by successively passing both cam followers in troughs of their cams during overlapping transitory positions of both cams.

A seventh embodiment of the invention shown in figure 20 also uses the third type of mode changing mechanism. The 'engine has four valves per cylinder, and each cam operates one valve in passive mode characterizing low speed operations of the engine, and two valves in another active mode characterizing high-speed operations. Cam follower 27 acting as a conventional rocker directly operates one valve at all times. It operates the extra valve, through the latch and lever in active mode disposition of the locator, as in the fifth embodiment of the invention.

Other means of actuation can also change cylinder modes. The description has throughout described hydraulic means of actuation. However, electrical, pneumatic, or mechanical energy can be alternately utilized to turn the mode selectors, to the same effect.

A motor cycle or outboard engine normally has one or two cylinders, and direct manual means can be employed for changing their mode, as shown in figure 21. The power output is controlled by accelerator handle 22. The engine idly runs with its cylinder in active mode, with accelerator handle 22 in middle position. The sheath of accelerator cable 9 is held by rotary holder 23 held next to accelerator handle 22 between top and bottom parts of retainer 24. One end of core of accelerator cable joins the throttle valve, while the other end joins the accelerator handle. Turning accelerator handle in one direction from idling position, increases power output of the engine by wrapping the core of accelerator cable 9 around cylindrical drum segment 40 of accelerator handle 22, with the top half of retainer preventing rotation of rotary holder with accelerator handle. The cylinders of the engine are changed to passive mode by reverse direction of rotation of accelerator handle. In this direction, accelerator handle 22 carries with it the rotary holder 23, extracting the core of mode-changing cable 30 from its sheath held by retainer 24. The other end of the core pulls the mode selector to passive mode position against pressure of a return spring 32, to change the operating mode of the cylinder to passive operating mode. Release of accelerator handle allows spring 32 to return the mode selector to active mode disposition for resuming active operations of the cylinder.

15 INDUSTRIAL APPLICABILITY

All types of internal combustion engines, -irrespective of number and configuration of cylinders, camshafts, valves, fuel mixing or injection systems, ignition systems and operating cycles, can derive benefits o the ϊhvention, and improve fuel-efficiency, reserve power and quality and quantity of emissions. Even other machines with cam-operated devices, such as gas compressors and industrial equipment can derive benefits of alternate device operations.

The invention helps vehicles with parallel hybrid engines, having an internal combustion engine as the prime mover, and another small engine, electric motor or energy storage device such as spring, flywheel or compressed fluid as auxiliary mover. The prime mover essentially provides greater reserve power to the vehicle, with accompaniment of smaller no-load losses with operations of all cylinders in passive mode, while the auxiliary mover can adequately service the lighter load.

Vehicle engines modified as per the invention produce fuel efficient operations and satisfactory torque across wider range of speeds and loads as compared to conventional engines, permitting use of fewer gear ratios in their transmission.

Disabling of cylinders is also a tool used for diagnosing engine problems. Alternate disabling of cylinders as per the invention can allow estimation of contribution of individual cylinders to net power output under running conditions. Periodic sequential deactivation of individual cylinders in steady load conditions can allow cylinders to be ranked according to their efficiencies of operations. Activation of cylinders can then follow the decreasing order of their efficiencies to get most fuel efficient operations from the engine. Efficient combustion in cylinders automatically reduces pollution.

Throughout the above description, reference is made to a radial cam profile with a lobe and trough in one axial plane. This is indeed the simple and preferred manner of carrying out the invention, though by no means an essentiality. Transitory positions of operating cam can be defined and detected by other mechanical or electronics means. Mechanical or electronically initiated means can stop the locator, or any other component of the mode changing mechanism, from changing towards the position of the changed mode outside said transitory

16 positions. Such means and mechanisms are included in the scope of the present invention.

TABL ,E I

Plot Parameter Rise signifies s

1) Accelerator pedal position lift

2) Total power output increase

3) Throttle position opening

4) Status of first activated cylinder activation st

5) Power output for 1 cylinder increase

6) Status of each other cylinder activation

7) Power output of each other cylinder increase

TABLE II

Plot Parameter Rise indicates

1) Accelerator pedal position lift

2) Cam radius under suction rocker high radius

3) Cam radius under exhaust rocker high radius

4) Mode selector rotary position active mode position

5) Status of lock 18a for suction locator locking

6) Position of suction locator active mode position

7) Status of lock 18b for exhaust locator locking

8) Position of exhaust locator active mode position

9) Position of suction carrier higher level

10) Position of exhaust carrier higher level

I D Suction valve closed

12) Exhaust valve closed

17

Claims

1. Internal combustion engine or like machine having at least one device (14) movable between open and closed positions on body (1), device closing means (16) for closing said device, device opeήr g^x means comprising cam" follower (4, 27) for opening said device in active positions of cyclically moving cam (3), characterized by- locator (12) movably held by said body joining to and movable with at least one component of said device opening means (13), said cam positions in each cycle comprising transitory positions, substantially excluding said active positions, mode selective means for moving said locator between active and passive dispositions on said body, said cam follower means with said cam in other than said transitory positions for disabling movement of said locator by said mode selective means to one intermediate disposition between active and passive dispositions, disabling of said device opening means that are enabled by said locator in active disposition, in passive disposition of said locator for at least one active position of said cam.

1. Internal combustion engine or like machine as in Claim 1 characterized by disabling of said device opening means in passive disposition of said locator for all active positions of said cam.

2. Internal combustion engine as in claim 1 characterized by four-stroke operating cycle comprising of suction, compression, expansion and exhaust strokes, two of said devices being a suction valve and an exhaust valve of a cylinder, two of said cams, each cam operating one of said valves, the cam operating suction valve assuming transitory positions within expansion and exhaust strokes of the cycle, and cam operating exhaust valve assuming transitory positions within suction and compression strokes of the cycle.

3. Internal combustion engine or like machine as in Claim 1, characterized by radial cam profile with a generally uniform base radius excepting for an angular region of lobe with larger radii and another angular region of trough with smaller radii, said active

18 positions of cam being rotary positions with incidence of said lobe under said cam follower, said transitory positions of cam being rotary positions with incidence of said trough under said cam followen, said mode selective means for moving said locator through said intermediate disposition by entering said cam follower into said trough of cam profile within said transitory positions of cam.

5. Internal combustion engine or like machine as in Claim 4 characterized by said device opening means comprising said cam follower held by a carrier (13), said locator joining to and movable with said carrier, said locator in passive disposition disabling said device opening means by moving said carrier more distant from either of said cam and said device than in active disposition of said locator.

6. Internal combustion engine or like machine as in Claim 4 characterized by said device opening means comprising a cam follower held by a first carrier and a lever (46) joining said device held by a second carrier, one of said two carriers joining and movable with said locator, said locator in passive disposition disabling said device opening means by moving said movable carrier more distant from either of said cam and said device than in active disposition of said locator.

7. Internal combustion engine or like machine as in Claim 4 characterized by said device opening means comprising lever (46) cam follower (45) and spacer (47), said lever joining said device, said cam follower joining said cam, both said lever and said cam follower carried by one carrier fixed to engine body, said spacer joining to and movable with said locator carried by another carrier movable with respect to engine body, said locator in passive disposition disabling said device opening means by moving said movable carrier and reducing width of said spacer between said lever and cam follower for absorbing motion of said cam follower by said cam without said movement affecting said lever joining closed said device.

8. Internal combustion engine or like machine as in Claim 1 characterized by said mode selective means comprising a mode selector movably held on body 1, at least one mode spring joining said mode selector and said locator, said mode selective means for moving said locator comprising of asynchronous means for moving said mode selector for

19 stressing said mode spring and synchronous means in transitory positions of said cam for relieving stress in said mode spring with movement of said locator.

9. Internal combustion engine or like machine as in claim 8 characterized by said mode selective means comprising locking means for holding said locator to said body till said mode selector stresses said mode spring sufficiently for moving said locator through said intermediate disposition with connected components of device opening means within the period of transitory positions of a cam cycle at highest engine speed.

10. Internal combustion engine or like machine as in claim 1 characterized by said mode selective means being hydraulic means using lubricating oil of the engine as hydraulic medium.

20 AMENDED CLAIMS

[received by the International Bureau on 30 August 1999 (30.08.99); original claims 1-10 replaced by amended claims 1-13 (5 pages)]

AMENDED CLAIMS

1. Internal combustion engine or like machine having at least one device ( 14, 15) movable between open and closed positions on body ( 1), device closing means (16), device'opening means comprising cam follower (4a.4b) means for periodic opening of said device with incidence on larger cam radii than a base cam radius in active positions of rotating cam (3a,3b), characterized by:

-passage of said cam through a range of rotary positions called transitory positions in each rotation, said transitory positions being mutually exclusive of said active positions, -said body (1) carrying at least one movable locator (12a, 12b) joined to move with at least one movable component (13a. l3b) of said device opening means called carrier-,

-mode selective means for moving said locator from one to other of active and passive dispositions on said body within interval of time between said active positions of consecutive cam rotations.

- said carrier means, with said device being not more open than by said cam means and said cam follower being incident over said cam in other than said transitory positions, for barring said locator from a range of restricted dispositions that are transitional dispositions between said active and passive dispositions. - said mode selective means, being powerless to more open said device than by said cam means against said device closing means, for synchronously passing said locator through said restricted dispositions within period of transitory positions of said cam between said active positions of said consecutive cam rotations,

- at least one of said active positions of said cam in which said device opening means that are enabled in active disposition of said locator are disabled by said locator in passive disposition.

2. Internal combustion engine or like machine as in Claim 1 with significantly smaller cam radii than said base cam radius in a trough region of said cam. said cam

AMENDED SHEET (ARTICLE 19) 21 trough for being incident under said cam follower in said transitory positions, said mode selective means for moving said locator through said restricted dispositions in said transitory cam positions comprising said carrier means for impelling part of said cam follower in said trough of cam with said device in said closed position.

3. Internal combustion engine or like machine as in Claim 1 with said locator in passive disposition for disabling said device opening means in all said active positions of said cam.

4. Internal combustion engine as in claim 1 with at least one cylinder operating in four-stroke cycle comprising suction, compression, expansion and exhaust strokes, a camshaft (2) bearing at least two of said cams comprising suction cam (3 a) and exhaust cam (3b) for said cylinder, each of said cams for opening one each of two said devices comprising suction valve (14) and exhaust valve ( 15) for said cylinder, said suction cam for assuming said transitory positions substantially within said expansion and exhaust strokes, said exhaust cam for assuming said transitory positions substantially within said suction and compression strokes.

5. Internal combustion engine or like machine as in Claim 2 with said carrier (13a, 13b) holding said cam follower, said cam follower connecting to said device ( 14, 15), said locator (12a, 12b) means in said passive disposition for disabling said device opening means comprising said carrier means for distancing said cam follower from at least one of said cam and said device than in said active disposition, said mode selective means for moving said locator through said restricted dispositions comprising said carrier means with said locator in said restricted dispositions for impelling part of said cam follower into said trough of cam with detention of another portion of said cam follower by said device in closed position.

6. Internal combustion engine or like machine as in Claim 2 with said device opening means having at least two carrying components, first said carrying component (6a, 6b) for carrying said cam follower (27a,27b) connecting to said cam (3a,3b), second said carrying component (13a, 13b) for carrying lever (28a,28b) connecting to said cam follower and said device ( 14, 15), said carrier being one of aforesaid carrying components, said locator means in passive disposition for disabling said device

AMENDED SHEET (ARTICLE 19) 22 opening means comprising said carrier means for distancing held cam follower or lever from connecting one of said cam and said device than in said active disposition of said locator, said mode selective means for moving said locator through said restricted dispositions comprising said carrier means with said locator in said

/ restricted dispositions for impelling part of said cam follower into said trough of cam with detention of said lever by said device in closed position.

7. Internal combustion engine or like machine as in Claim 2 with a lever (28) component of said device opening means connecting to said device, said cam follower (27) connecting to said cam, said device opening means further comprising a spacer (29) held by said carrier (43), said cam follower means for periodically opening said device in active disposition of said locator comprising said cam follower means of moving said lever by transferring motion through said spacer, said carrier means in active disposition of said locator for positioning said spacer between said cam follower and said lever to approximately close the gap between said lever and said cam follower with said lever incident over said device in closed position and said cam follower incident over said base cam radius, said locator means in said passive disposition for disabling said device opening means comprising said carrier means for repositioning said spacer for allowing said cam follower to close in towards said lever than in said active disposition, said mode selective means for moving said locator through said restricted dispositions comprising said carrier means with said locator in said restricted dispositions for repositioning said spacer for distancing said cam follower from said lever than in said active disposition of said locator, said repositioning for impelling part of said cam follower into said trough of cam with detention of said lever by said device in closed position.

8. Internal combustion engine or like machine as in Claim 1 with said mode selective means for moving said locator comprising at least one mode spring ( 17) or like energy storing device, at least one mode selector ( 1 1) movably held between active and passive dispositions on said body, said mode spring joining said mode selector and said locator, said mode selective means comprising of two phases, first of said phases comprising means for energizing said mode spring by movement of

AMENDED SHEET (ARTICLE 19) 23 said mode selector from said one to other of active and passive dispositions without movement of said locator, said mode spring for de-energizing by movement of said locator to last changed disposition of said mode selector in said second of said phases.

9. Internal combustion engine as in claim 8 with said body or its fixture (5) for rotably carrying said locator (12) between said active and passive dispositions, said body or its fixture (7) preventing rotation of said locator beyond said active and passive dispositions, partial incidence of both ends of said mode spring against each of said mode selector and said locator, stressing of said mode spring from one each of ends by mode selector movement to each one of active and passive dispositions in said first phase, said mode spring for releasing said stress from opposite end by moving said locator in said second phase.

10. Internal combustion engine or like machine as in claim 8 with said mode selective means comprising locking means (18a, 18b) for said locator to said body in said first phase, said means for moving said mode selector to one of said active and passive dispositions comprising means for disabling said locking means in close proximity of said dispositions for commencement of said second phase after adequate storage of energy in said mode spring for moving said locator between said active and passive dispositions with resultant movements of connected components of said device opening means within interval of time between said active positions of said consecutive cam rotations.

11. Internal combustion engine as in claim 10 with at least one cylinder operating in four-stroke cycle comprising suction, compression, expansion and exhaust strokes, two of said devices being a suction valve and an exhaust valve for one cylinder, two of said cams being a suction cam and an exhaust cam for opening one each of said devices, said transitory positions of said suction cam substantially coinciding with said expansion and exhaust strokes, said transitory positions of said exhaust cam substantially coinciding with said suction and compression strokes, said mode selector (11) joining each of two locators (12a, 12b) with one each of two mode springs (17a, 17b), one of said locators being suction locator (12a) for disabling operations of said suction valve, another of said locators being exhaust locator (12b) for disabling

AMENDED SHEET (ARTICLE 19) 24 operations of said exhaust valve, said locking means for locking each of said suction locator in said active disposition and said exhaust locator in said passive disposition comprising one of locks (18) carried by body (1), disabling of said locking means for said suction locator and said exhaust locator by movement of said mode selector to said passive and active dispositions respectively, said locking means for locking each of said exhaust locator in active disposition and said suction locator in passive disposition comprising interlocking means by said other locator in similar disposition, said suction locator by moving from said active disposition in said expansion and exhaust strokes for disabling said interlocking means for allowing movement of said exhaust locator from said active disposition through said restricted dispositions in following suction and compression strokes, said exhaust locator by moving from said passive disposition in said suction and compression strokes for disabling said interlocking means for allowing movement of said suction locator from said passive disposition through said restricted dispositions in following expansion and exhaust strokes.

12. Internal combustion engine as in Claim 11 with a component (4b) of said device opening means for said exhaust valve (15) hindering said mode selective means for moving said suction locator (12a) to said passive disposition till midway in said exhaust stroke, said suction locator in said passive disposition for hindering movement of said component of device opening means (4b) with said exhaust valve at end of exhaust stroke for preventing full closure of said exhaust valve with said device closing means (16).

13. Internal combustion engine as in Claim 8 with manually operated accelerator (8) means for controlling power output of said engine, said means for moving said mode selector to said passive disposition comprising manual means for moving said accelerator to one passive end position, said means for moving said mode selector to said active disposition comprising manual means for moving said accelerator from said passive end position to one intermediate neutral position, said movement of accelerator (8) beyond said neutral position for controlling power output of said engine.

AMENDED SHEET (ARTICLE 19) 25 "Statement under article 19(1)"

/

All claims are amended to clearly state the novel features of the invention, particularly in context of references cited in the international search report. The proposed amendments do not necessarily require changes in description or figures. The components referred in amended claims 5, 6 and 7 relate to three generic types of mode changing mechanisms described in description, and illustrated in figures 1-12, 13-16, and 17, respectively. Because of amendments to claims, some components are variously named in description and claims; however, numerals in parenthesis remove any ambiguity.

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