WO2007092168A2

WO2007092168A2 - Combustion pressure sensor

Info

Publication number: WO2007092168A2
Application number: PCT/US2007/002037
Authority: WO
Inventors: Edward Charles Mendler
Original assignee: Edward Charles Mendler
Priority date: 2006-02-02
Filing date: 2007-01-24
Publication date: 2007-08-16
Also published as: WO2007092168A3

Abstract

A method an apparatus is provided for sensing combustion pressure preferably in variable compression ratio engines having a hydraulic actuator. A low cost hydraulic pressure sensor is placed in the hydraulic actuator of the variable compression ratio engine for sensing combustion loads applied on the crankshaft support structure. Pressure readings from the sensor are indexed to crankshaft rotational angle for correlating pressure readings from the sensor to individual engine cylinders. The sensor enables real-time closed loop engine control in spark-ignition and diesel engines, as well as in homogeneous charge compression-ignition engines.

Description

COMBUSTION PRESSURE SENSOR

This application relates to Provisional Application No. 60/764,951 having a filing date of February 2, 2006.

BACKGROUND OF THE INVENTION

Automotive internal combustion engine efficiency, power, combustion stability and emissions control can be improved by real-time adjustment of engine settings in response to pressures inside the engine cylinders. Engine settings that may be adjusted include spark timing, intake air flow rate, valve timing, compression ratio, exhaust gas recirculation or EGR flow rates, as well as other engine control variables. A problem however is that a low-cost durable sensor for measuring pressure inside the engine cylinders in real-time is not available.

Knock sensors have been used for some time in turbocharged engines. A problem with these sensors is that they indicate the occurrence of detonation within the cylinder but do not indicate actual cylinder pressures. Actual cylinder pressure readings are needed to optimize engine settings when the engine is operated both at small power levels where detonation is unlikely and at higher power levels where adjustment of engine settings is needed to avoid detonation. An additional problem with earlier knock sensors is that they are not always reliable or capable of indicating detonation or near detonation conditions.

Knock sensors are shown in a number of variable compression ratio engines. In US Patent number 6,990,934 issued on January 31, 2006 Sugiyama et al. of Nissan Motor Company shows in their variable compression ratio engine a knock sensor part number 8 in Fig. 1. In US Patent number 6,970,781 issued on November 29, 2005 Chen et al. of Ford Global Technologies shows in their variable compression ratio engine a knock sensor part number 140 in Fig. 1. In US Patent Application Publication no. US 2005/0028760 issued February 10, 2005 Akihisa et al. of Toyota show a sensor in their variable compression ratio engine. In US 6,443,124 issued September 3, 2002 Mendler shows in his variable compression ratio engine a knock sensor in Fig. 6. In US 6,125,801 issued on October 3, 2000 Mendler shows in his variable compression ratio engine a knock sensor part number 52 in Fig. 2.

Piezoelectric sensors sold by Kistler and other companies can be used to measure combustion pressure in real time, but cost about $2,600 each. These sensors are too expensive for use in passenger cars. Sensors that measure gas conductivity across the sparkplug gap are anticipated to have problems of cost, durability and accuracy considering sparkplug life-cycle aging. A combustion pressure sensor is also needed for controlled auto-ignition engines also known as homogeneous charge compression-ignition engines and commonly referred to as CAI or HCCI engines. These engines typically operate under conditions where a knock sensor is incapable of providing combustion pressure readings needed for control of the CAI or HCCI engine. Because of the large potential improvement in fuel efficiency and emissions reduction that CAI and HCCI engines can bring, the U.S. Department of Energy issued on January 26, 2006 Funding Opportunity Announcement Number DE-PS26-06NT42718-00 for providing research and development funding for Advanced Start- of Combustion sensors. A major problem with HCCI combustion is that the timing of combustion is not well controlled and consequently erratic. The erratic combustion timing of HCCI engines is a major barrier to their commercialization. A sensor that indicates combustion pressure is needed for providing control of HCCI engines.

The objective of the present invention is to provide a low-cost highly reliable sensor for measuring pressure in the engine's cylinders in real-time. Data readings from the sensor will be used to adjust engine settings preferably in real-time with closed-loop engine control for optimizing engine efficiency, power, combustion stability and/or emissions control. A further objective is to provide a combustion pressure sensing system to enable control of CAI and HCCl engines.

SUMMARY OF THE INVENTION

According to the preferred embodiment of the present invention a hydraulic pressure sensor is placed in the hydraulic actuator of a variable compression ratio engine. Combustion forces are transferred through the variable compression ratio mechanism to the hydraulic actuator. Combustion pressure is sensed according to the preferred embodiment of the present invention by measuring hydraulic pressure inside the hydraulic actuator used for varying compression ratio. The hydraulic pressure sensor is located away from the combustion chamber in a relatively cool and protected location of the engine. Hydraulic pressure sensors are commercially available that have low cost, about $50, and that are highly durable and reliable.

The hydraulic pressure sensor used in the current invention will preferably replace the traditional knock sensor. In engines having variable compression ratio, the hydraulic pressure sensor will add no or nearly no cost to the engine when the cost of the traditional knock sensor is eliminated. The hydraulic pressure sensor of the present invention will provide a major improvement in combustion sensing capability over the traditional knock sensor. Specifically the pressure sensing system of the present invention can be employed for determining combustion pressure in contrast to knock sensors that can only indicate the occurrence of detonation or knock. The combustion pressure sensing system of the present invention will enable improved control of CAI and HCCI engines, as well as improved efficiency, power and reduced emissions from conventional spark-ignition and diesel engines. In other embodiments of the present invention an electric sensor may optionally be used instead of a hydraulic sensor. Electrical sensors may have advantages in variable compression ratio engines that employ electrical actuators instead of hydraulic actuators for varying compression ratio.

The present invention may also be practiced in engines that do not have variable compression ratio. In these engines the sensor or load sensor as it is more generally referred to measures combustion forces applied to the crankshaft support structure of the engine.

Signals from the sensor are optionally correlated with crankshaft rotational angle for determining pressure from individual cylinders. Settings for individual cylinders are optionally individually adjusted for providing optimum engine efficiency, power, optimum emissions control, and/or improved control of other engine qualities. The present invention is preferably used for realtime closed-loop control of engine settings.

The present invention provides a low-cost, durable, and reliable apparatus and method of determining combustion pressure in real-time. The present invention will be employed for increasing engine efficiency, reducing engine emissions and increasing engine power. The present invention enables improved control of CAI and HCCI engines. CAI and HCCI engine technology offers potential for large gains in engine efficiency as well as large reduction in emissions from diesel engines.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is intended to illustrate a combustion pressure sensing apparatus according to the present invention.

Fig. 2 shows a detailed view of the hydraulic cylinder shown in Fig. 1.

Fig. 3 is intended to illustrate the applied and reactive loads acting on the eccentric support shown in Fig. 1.

Fig. 4 is similar to Fig. 1 but shows a combustion pressure sensing apparatus in a first multi- link variable compression ratio engine.

Fig. 5 is similar to Fig. 1 but shows a combustion pressure sensing apparatus in a second multi- link variable compression ratio engine.

Fig. 6 is similar to Fig. 1 but shows a combustion pressure sensing apparatus in a third variable compression ratio engine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1 is intended to illustrate a portion of a variable compression ratio engine 1 having a combustion pressure sensing system according to the present invention. Engine I has a piston 2, a cylinder 4, and a combustion chamber 6. Preferably cylinder 4 includes an intake port 8 for admitting air into cylinder 4 and an exhaust port 10 for release of combustion gasses from cylinder 4. Cylinder 4 may optionally include a spark plug and/or a diesel or gasoline fuel injector 11.

Engine 1 further includes an engine block or housing 12 and an actuator mount 14. Actuator mount 14 is preferably rigidly attached to the engine block 12, and optionally may be included in the engine block casting (shown) or may be a fixed or adjustable bracket attached to engine block 12 (not shown). Fig. 1 is intended to schematically illustrate cylinder 4 joined to actuator mount 14 by housing 12.

Engine 1 further includes a connecting rod 16, a crankshaft 18 having an axis of rotation 20, and an eccentric carrier or support 22 having a pivot or rotational axis 24 and a pivot angle 25 in housing 12. Eccentric carrier 22 preferably includes a clevis 26 for adjusting the pivot angle 25 of eccentric carrier 22 in housing 12 about pivot axis 24. Connecting rod 16 connects piston 2 to crankshaft 18 for reciprocating motion of piston 2 in cylinder 4. Engine 1 further includes crankshaft main bearings 19 for supporting crankshaft 18. In the embodiment of the present invention shown in Fig. 1, crankshaft main bearings 19 are mounted in eccentric carrier 22.

Engine 1 further includes a hydraulic cylinder or actuator 28 having a ram 30, a ram pin 31, and a mounting pin 32. Hydraulic cylinder 28 connects clevis 26 to actuator mount 14. Extension and retraction of ram 30 in hydraulic cylinder 28 adjusts the pivot angle 25 of eccentric carrier 22 in engine housing 12 for adjusting the location of the crankshaft axis of rotation 20 in housing 12. Adjusting the location of crankshaft axis 20 in engine housing 12 adjusts the compression ratio of engine 1.

Fig. 2 is a detailed view of hydraulic cylinder 28 shown in Fig. 1. Figs. 1 and 2 are intended to illustrate the preferred embodiment of the present invention. Hydraulic cylinder 28 includes a first hydraulic chamber 34 in fluid communication with a first hydraulic line 36. Hydraulic cylinder 28 also includes a second hydraulic chamber 38 in fluid communication with a second hydraulic line 40. Hydraulic cylinder 28 includes a piston 42 attached to ram 30 and separating first hydraulic chamber 34 from second hydraulic chamber 38. Hydraulic cylinder 28 may include a control valve such as a spool valve 44 for controlling fluid flow in and out of hydraulic chambers 34 and 38 through hydraulic lines 36 and 40 for adjusting the position of ram 30. Engine 1 may also include an engine controller or controller 46 and control wire 48 for controlling control valve 44 and controlling the position of ram 30. Controller wire 48 preferably connects controller 46 to control valve 44.

According to the present invention, hydraulic cylinder 28 may also includes a first pressure sensor 50 mounted in line 36 for measuring hydraulic pressure in hydraulic chamber 34. Hydraulic cylinder 28 may also include a second pressure sensor 52 mounted in hydraulic chamber 38 for measure hydraulic pressure in hydraulic chamber 38. Pressure sensors 50 and 52 preferably include lead wires 54 and 56 for transmitting pressure signals from pressure sensors 50 and 52 to controller 46. Signals from the pressure sensor or load sensor are preferably input directly into controller 46. Referring now to Figs. 1 and 2, the present invention may be practiced with other functional actuators or hydraulic cylinders and other functional sensor arrangements.

According to the preferred embodiment of the present invention, engine 3 including a crankshaft support 23. In the embodiment of the present invention shown in Figs. 1 and 2, crankshaft support 23 includes eccentric carrier or support 22. According to the present invention, engine 1 includes a load sensor 51. In the embodiment shown in Figs. 1 and 2, load sensor 51 includes pressure sensor 50 and/or 52. Preferably, according to the present invention, load sensor 51 is placed in and/or included in crankshaft support 23 for measuring load on the crankshaft support. Fig. 4 show a crankshaft support 123 having a load sensor 151, and Fig. 5 shows a crankshaft support 223 having a load sensor 251. According to the present invention, various types of crankshaft supports and load sensors may optionally be used. The load sensors may optionally include hydraulic or electric sensing means. According to the present invention, the sensor or sensing means may be placed in any functional location for measuring combustion forces applied to the support structure. The crankshaft support preferably includes variable compression ratio, however variable compression ratio is not required according to the present invention.

According to the present invention, pressure in combustion chamber 6 produces a first reaction pressure 58 in hydraulic chamber 34, pressure in combustion chamber 6 being transmitted to hydraulic chamber 34 through piston 2, connecting rod 16, crankshaft 18, eccentric carrier 22, clevis 26, ram 30 and piston 42. In the preferred embodiment of the present invention sensor 50 transmits a signal to controller 46 indicating the magnitude of first reaction pressure 58.

According to the present invention, pressure in combustion chamber 6 produces a second reaction pressure 60 in hydraulic chamber 38, pressure in combustion chamber 6 being transmitted to hydraulic chamber 38 through piston 2, connecting rod 16, crankshaft 18, eccentric carrier 22, clevis 26, ram 30 and piston 42. In the preferred embodiment of the present invention sensor 52 transmits a signal to controller 46 indicating the magnitude of second reaction pressure 60. According to the preferred embodiment of the present invention one or more sensors are located on one or both sides of piston 42, and located in fluid communication with hydraulic chamber 34 and/or 38, either directly in the hydraulic chamber or in a hydraulic passage or chamber in fluid communication with the hydraulic chamber.

Pressure in hydraulic chambers 34 and 38 fluctuate with crankshaft rotation in response to pressure in combustion chamber 6, inertial forces of the reciprocating piston assembly and other factors. Controller 46 is preferably programmed to take into account forces acting on ram 30 not attributable to pressure in combustion chamber 6.

The present invention provides a durable low cost sensing apparatus for measuring the combustion pressure of internal combustion engines. According to the present invention, at least one piston 2 is mounted for reciprocating motion in engine 1, and crankshaft 18 defines an axis 20 about which the crankshaft rotates. Connecting rod 16 connects piston 2 to crankshaft 18. Crankshaft 18 is supported by crankshaft main bearings 19.

Preferably engine 1 is a variable compression ratio engine, however the present invention may be practiced in engines that do not have variable compression ratio. Engine 1 including a crankshaft support 23. In the embodiment of the present invention shown in Fig. 1 crankshaft support 23 includes eccentric carrier or support 22. As described earlier, other types of support structures may optionally be used according to the present invention. Figs. 4 and 5 show a linkage type support structure.

Referring now to Figs. 1 and 3, crankshaft support 23 has an applied load A and a reactive load R that are dependent on the combustion pressure in combustion chamber 6. In the embodiment shown in Figs. 1 and 3 the applied load A applies a torque in eccentric carrier 22 about axis 24. Reactive load R exerts an opposing torque on eccentric carrier 22 thereby preventing eccentric carrier 22 from rotating when adjustment of engine compression ratio is not desired. Applied load A is transmitted from crankshaft ] 8 to eccentric carrier 22 through crankshaft main bearings 19. Reactive load R is dependent on the combustion pressure in combustion chamber 6, the crankshaft rotational angle, the spacing between the crankshaft axis of rotation 20 and pivot axis 24, the spacing between ram pin 31 and pivot axis 24, and other factors.

Sensor 52 is positioned for measuring reactive load R, and in more detail sensor 52 provides a sensor output signal for determining combustion pressure. Referring now to Figs. 1, 2 and 3, in the preferred embodiment of the present invention controller 46 interprets the sensor output signal from sensor 52 thereby enabling control of engine 1 in response to combustion pressure. In the embodiment of the present invention shown in Figs. 1 and 2, sensor 52 is a hydraulic pressure sensor mounted in hydraulic cylinder 28 for measuring hydraulic pressure in hydraulic chamber 38. Fig. 4 shows electric sensors or sensing means. Hydraulic or electric sensor or sensing means may be used according to the present invention.

The hydraulic pressure sensor 52 is positioned for measuring the reactive load R on the crankshaft support. In the embodiment shown in Fig. 2, sensor 52 is in fluid communication with hydraulic cylinder or actuator 28, and in fluid communication with hydraulic chamber 38. Sensor 52 provides a sensor output signal for determining combustion pressure in combustion chamber 6. The crankshaft support 23 shown in Fig. 1 includes variable compression ratio and eccentric carrier 22. Referring now to Fig. 2, the variable compression ratio includes a first compression ratio setting when ram 30 is at position 62, a second compression ratio setting when ram 30 is at position 64, and hydraulic cylinder or actuator 28 for adjusting compression ratio from the first compression ratio setting to the second compression ratio setting. Other types of variable compression ratio mechanisms may be used according to the present invention. Figs. 4 and 5 show a linkage type variable compression ratio mechanism having a pressure sensing system according to the present invention.

A major advantage of the present invention as shown in Figs. 1 and 2 is that the combustion pressure sensor is of the hydraulic type and is located in a relatively cool location, thereby enabling combustion pressure to be measured in real-time with a low-cost durable sensor. Sensor 52 may optionally be positioned in other locations for measuring hydraulic pressure within hydraulic cylinder 28. Sensor 52 may be mounted for directly measuring pressure in hydraulic chamber 38 (shown), or in fluid communication with chamber 38 through a duct or line. Optionally one or more additional sensors may be used such as sensor 50. Optional sensor 50 is shown mounted in line 36 and in fluid communication with hydraulic chamber 34. Preferably only sensor 52 is employed in order to minimize cost, however additional sensors may be employed according to the present invention.

Preferably the combustion pressure sensing apparatus of the present invention is practiced in variable compression ratio engines, where the crankshaft support includes the variable compression ratio mechanism.

Referring now to the embodiment of the present invention shown in Figs. 1, 2 and 3, preferably crankshaft support 23 and the variable compression ratio mechanism includes at least one eccentric support 22 having pivot or rotational axis 24 and offset axis 20, where at least one of the crankshaft main bearings 19 is mounted in eccentric support 22 concentric with offset axis 20. In more detail, eccentric support 22 defines rotational axis 24 about which the eccentric support pivots. Offset axis 20 is preferably parallel to rotational axis 24. Offset axis 20 is spaced apart from rotational axis 24. Eccentric support 22 has a reactive load or torque R, reactive load or torque R being dependent on the combustion pressure in combustion chamber 6 as well as other factors. The sensor is positioned for measuring the reactive load and providing a sensor output signal for determining combustion pressure. Controller 46 is preferably programmed to take into account forces acting on ram 30 not attributable to pressure in combustion chamber 6. In the preferred embodiment controller 46 determines or distinguishes combustion pressure from the sensor reading and enables improved control of engine 1 in response to combustion pressure.

Referring now to Fig. 4, the sensor may optionally be an electric sensor. Referring now to Figs. 1, 4 and 5, the variable compression ratio mechanism may optionally be a multi-link variable compression ratio mechanism or another type of variable compression ratio mechanism. According to the present invention, a sensor is positioned for measuring the reactive load on the support structure and/or variable compression ratio mechanism, and the sensor provides a sensor output signal for determining combustion pressure and/or measuring the reactive load on the support structure or variable compression ratio mechanism. The sensor may be a hydraulic sensor or an electric sensor or sensing apparatus, such as means for measuring change of torque in an electric actuator motor.

Referring now to Figs. 1 and 2, sensor 52 has a sensor output signal. Preferably the sensor output signal from sensor 52 is an input signal into engine controller 46 transmitted through wire 56. Controller 46 has a plurality of control output signals for providing a plurality of engine settings.

In more detail, variable compression ratio settings can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to control valve 44 through control wire 48.

Ignition settings can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to ignition system 11 through control wire 68.

Valve actuation settings can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to valve system 70 through control wire 72.

Boost pressure settings can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to boost system 74 through control wire 76. Fuel injection settings can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to fuel injection system 78 through control wire 80. Fuel may optionally be injected directly into the combustion cylinder of the engine.

Transmission gear ratio can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to the transmission gear selector system through transmission wire 82.

Air mass flow into intake port 8 can optionally be controlled by a control output signal from controller 46, optionally with a control output signal from controller 46 passing to a throttle 88 through control wire 90.

Controller 46 has at least one control output signal being dependent on an input signal from a sensor positioned for measuring reactive load according to the present invention, such as load sensor 51, 50 and/or 52, thereby providing improved efficiency, increased power and/or reduced emissions from engine 1.

In more detail, preferably at least one control output signal is selected from the group • consisting of a variable compression ratio control output signal, an ignition control output signal, a valve actuation control output signal, a boost pressure control output signal, a fuel injection control output signal, air mass flow control output signal, and a transmission gear ratio control output signal. According to the present invention, each control output signal may take any form as needed for control and/or adjustment of the engine settings.

The present invention teaches a method of controlling an internal combustion engine, the internal combustion engine being operable in a plurality of engine settings, the method comprising: placing a load sensor in the crankshaft support; input signals from the load sensor into engine controller 46; and adjust one or more engine settings with engine controller 46 in response to input signals obtained from load sensor 51.

One or more of the following engine or cylinder settings may optionally be adjusted with controller 46 in response to input signals obtained from load sensor 51 : engine compression ratio; ignition timing; valve timing;, lift, and/or other valve actuation; boost pressure; fuel injection; air mass flow; or other engine settings. Valve actuation refers to the valves used for control of intake and exhaust gasses into and out of cylinder 4 and combustion chamber 6. Engine 1 preferably includes an engine timing sensor 84 for determining the rotational angle of crankshaft 18. Fig. 1 shows timing sensor 84 connected to controller 46 with a timing wire 86. The method of controlling engine 1 may optionally further including the step of correlating load sensor readings from load sensor 51 to crankshaft rotational angle for determining individual cylinder conditions. According to the present invention, the pressure within an individual cylinder in a multi- cylinder engine can be predicted by correlating the sensor output signal from load sensor 51 to crankshaft rotational angle readings from timing sensor 84. Fig. I is intended to illustrate sensor output signals in general from load sensor 51, preferably from pressure sensors 50 and 52.

In engines having more than one cylinder 4, according to the present invention, controller 46 may optionally determine optimum settings for each individual cylinder and/or for groups of cylinders. The method of controlling engine 1 may optionally further including the step of providing individual settings to two or more cylinders. In more detail two cylinders in engine 1 may have different settings for providing improved efficiency, increased power, and/or reduced emissions.

Fig. 4 shows a portion of a multi-link variable compression ratio engine 100 having a combustion pressure senescing apparatus according to the present invention. Engine 100 may include a piston 2, a cylinder 4, an engine block or housing 12, a combustion chamber 6, a crankshaft 131, and a crankshaft support 123. Crankshaft support 123 includes a journal or crankshaft main bearing 132, a crankpin 133, a lower link 134, an upper link 135, a connecting pin 136, a control link 140, a connecting pin 141, a control shaft 142, preferably having a large diameter portion 142a and a small diameter portion 142b, and an actuator 143. Engine 100 may include a gear drive 144 or other functional means for turning control shaft 142 with actuator 143. Actuator 143 may be an electric actuator or a hydraulic actuator.

According to the present invention, crankshaft support 123 includes a load sensor 151 for measuring load on the crankshaft support, and in more detail for sensing combustion pressure. According to the present invention, load sensor 151 may include a first electric or hydraulic sensor 146, and a first connection wire 154 for connecting sensor 146 preferably to the engine controller. According to the present invention, load sensor 151 may include a second electric or hydraulic sensor 148, and a second connection wire 156 preferably for connecting sensor 148 to the engine controller. According to the present invention, load sensor 151 may include a third electric or hydraulic sensor located in a third functional location for measuring load on crankshaft support 123, such as sensor 150. According to the present invention, actuator 143 may be electric or hydraulic, and load sensor 151 may include electric or hydraulic sensors. In embodiments including an electric actuator, sensor 146 may optionally detect the value of the current supplied to the electric actuator oτ motor that rotates gear drive 144. Sensor 146 may optionally detect the angle of rotation in a resilient members such as a torsion springs interposed between the actuator and gear drive 144. Sensor 146 may employ other functional sensing means.

Fig. 5 is similar to Fig. 4, but shows an actuator 243 for turning control shaft 142. Control shaft 142 preferably includes a clevis 242 for connection to actuator 243. Actuator 243 may optionally be similar in construction to actuator 28 shown in Fig. 1. Preferably actuator 243 includes a hydraulic or electric sensor 246 and a sensor wire 254 preferably for connection to the engine controller. Fig. 5 shows actuator mount 14 integrated into a structural oil pan or bedplate 214.

According to the present invention, a crankshaft support 223 includes a load sensor 251 for measuring load on the crankshaft support, and in more detail for sensing combustion pressure. According to the present invention, load sensor 251 may include an electric or hydraulic sensor 246, and a sensor wire 254 for connecting sensor 246 preferably to the engine controller. According to the present invention, actuator 243 may be electric or hydraulic, and load sensor 251 may include electric or hydraulic sensors or sensing means.

Fig. 6 shows another embodiment of the present invention in a variable compression ratio engine 300. Engine 300 includes a crankshaft support 323 having an upper cylinder block 303 having one or more cylinders 4, and a crankshaft 315 rotatably mounted in a lower case 304. One or more eccentric camshafts 309 movably pin upper cylinder block 303 and lower case 304, where rotation of camshafts 309 adjusts the spacing between upper cylinder block 303 and lower case 304 for adjusting engine compression ratio. Fig. 6 shows two camshafts 309, however a single camshaft can optionally be used. Typically a single camshaft system would include one or more links and a hinge pin. Preferably camshafts 309 are turned by a gear set including a worm wheels 310 and worm gear 31 1. Worm gear 31 1 is preferably turned by an electric or hydraulic actuator 312. According to the present invention crankshaft support 323 includes a load sensor 351 for measuring load on the crankshaft support and in more detail for sensing combustion pressure.. Load sensor 351 may include an electric or hydraulic sensor 348 attached to actuator 312 for sensing combustion pressure. Load sensor 351 may optionally include a sensor located in another location for sensing combustion pressure, such as sensor 350 located between the cylinder block 303 and lower case 304.

Claims

1. A durable low cost sensing apparatus for measuring the combustion pressure of internal combustion engines, including at least one piston mounted for reciprocating motion in said engine, a crankshaft defining an axis about which the crankshaft rotates, a connecting rod, and a plurality of crankshaft main bearings, further including a crankshaft support, said crankshaft support having a reactive load, said reactive load being dependent on said combustion pressure, and a sensor, said sensor being positioned for measuring said reactive load, wherein said sensor provides a sensor output signal for determining combustion pressure.

2. The durable low cost sensing apparatus of claim 1, wherein said crankshaft support includes a variable compression ratio mechanism.

3. The durable low cost sensing apparatus of claim 2, wherein said reactive load is a torque, said variable compression ratio mechanism having said reactive torque, said reactive torque being dependent of said combustion pressure, and said sensor being positioned for measuring said reactive torque, wherein said sensor provides a sensor output signal for determining combustion pressure.

4. The durable low cost sensing apparatus of claim 1, wherein said crankshaft support includes at least one eccentric support, said eccentric support having a rotational axis and an offset axis, wherein at least one of said crankshaft main bearings is mounted in said eccentric support concentric with said offset axis, said eccentric support having said reactive load, said reactive load being dependent of said combustion pressure, said sensor being positioned for measuring said reactive load, wherein said sensor provides a sensor output signal for determining combustion pressure.

5. The durable low cost sensing apparatus of claim 1, wherein said sensor is a hydraulic pressure sensor, said hydraulic pressure sensor being positioned for measuring said reactive load, wherein said sensor provides a sensor output signal for determining combustion pressure.

6. The durable low cost sensing apparatus of claim 2, wherein said sensor is a hydraulic pressure sensor, said hydraulic pressure sensor being positioned for measuring said reactive load, wherein said sensor provides a sensor output signal for determining combustion pressure.

7. The durable low cost sensing apparatus of claim 6, further including a first compression ratio setting, a second compression ratio setting, and a hydraulic actuator for adjusting compression ratio from said first compression ratio setting to said second compression ratio setting, wherein said sensor is a hydraulic pressure sensor is in fluid communication with said hydraulic actuator.

8. The durable low cost sensing apparatus of claim 2, wherein said sensor is an electrical sensor, said electrical sensor being positioned for measuring said reactive load, wherein said sensor provides a sensor output signal for determining combustion pressure.

9. The durable low cost sensing apparatus of claim 2, wherein said variable compression ratio mechanism is a multi-link variable compression ratio mechanism, said sensor being positioned for measuring said reactive load, wherein said sensor provides a sensor output signal for determining combustion pressure.

10. The durable low cost sensing apparatus of claim 1, further including an engine controller, wherein said sensor output signal from said sensor is an input signal into said controller, said controller having a plurality of control output signals for providing a plurality of engine settings, wherein said controller has at least one control output signal being dependent on said input signal from said sensor, thereby providing improved efficiency, increased power and/or reduced emissions from said engine.

1 1. The durable low cost sensing apparatus of claim 10, wherein said at least one control output signal is selected from the group consisting of variable compression ratio control signal, ignition timing control signal, valve timing control signal, boost pressure control signal, fuel injection timing control signal, fuel injection amount control signal, air mass flow control signal, and transmission gear ratio control signal.

12. A method of controlling an internal combustion engine, the internal combustion engine being operable in a plurality of engine settings, the method comprising: placing a load sensor in the crankshaft support; input signals from the load sensor into the engine controller; adjust one or more engine settings with the controller in response to input signals obtained from the load sensor.

13. The method of claim 12, wherein one of the engine settings adjusted by the controller is engine compression ratio.

14. The method of claim 12, wherein one of the engine settings adjusted by the controller is ignition timing.

] 5. The method of claim 12, wherein one of the engine settings adjusted by the controller is valve timing.

16. The method of claim 12, wherein one of the engine settings adjusted by the controller is boost pressure.

17. The method of claim 12, wherein one of the engine settings adjusted by the controller is fuel injection.

18. The method of claim 12, wherein one of the engine settings adjusted by the controller is air mass flow.

19. The method of claim 12, further including the steps of correlating load sensor readings to crankshaft rotational angle for determining individual cylinder conditions.

20. The method of claim 19, further including the steps of providing individual settings to two or more cylinders.