Omnivision Launches OmniBSI+ CameraCubeChip

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PRNewswire: OmniVision announces what it says is the industry's most compact VGA CameraCubeChip to date: the OVM7695. The camera module size is just 2.4 x 2.4 x 2.3 mm. The sensor is based on 1.75um OmniBSI+ pixel.

"Front-facing cameras have quickly become a defining feature in mobile devices. As these devices continue down the path of miniaturization, manufacturers are tasked with providing a better video recording experience within tighter space constraints," said Aaron Chiang, senior technical marketing manager at OmniVision.

The OVM7695 is currently sampling and is expected to enter volume production by the first quarter of 2013.

10:42 PM

Sony Applies for Tilted Pixel Patent

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Sony Alpha Rumors noticed Japanese language Egami post on the new Sony patent application talking about tilted pixel to increase the pixel density. Here is the Google translation:
  • If the incident light is incident perpendicularly, and the photoelectric conversion film thickness of the optical path length is equal
  • If the incident light is incident at an angle, the optical path length is longer than the film thickness of the photoelectric conversion film
  • That because of the long optical path length to improve the photoelectric conversion efficiency, high sensitivity can be obtained.

The patent application also talks about Foveon-like sensor structure.

Thanks to AA for the link!
2:37 PM

e2v Announces 2MP Sensor in Sapphire Family

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e2v has added the 2MP EV76C570 device to its Sapphire family of industrial CMOS sensors. A 1/1.8-inch sensor is based on 4.5um pixels. An extra effort has been spent to make it compatible with older 1.3MP sensors in Sapphire family, including the pinout, package, optical format and register banks retained to minimize customer efforts to adapt the new 2MP product.

The new sensor features:
  • Both rolling and global shutter configuration with high global shutter efficiency
  • Up to 60fps frame rate
  • 4 x separately configurable regions of interest including the possibility to programme each window with separate exposure and gain settings
  • A histogram embedded in the footer of the image data field for image statistics to reduce the processing overhead for auto exposure/gain algorithms
  • A lin/log pixel response mode for high dynamic range image capture
  • A 10 Bit parallel output which can be compressed to 8 bits using a multi-slope companding technique.
2:27 PM

First CMOS Sensor from Truesense Imaging

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Formerly known by its CCDs, Truesense Imaging re-enters CMOS image sensor market with the new 12MP 4/3-inch KAC-12040 based on 4.7um 5T global shutter pixel. The new sensor is delivers 60fps at full resolution of 100fps in 4K 8.3MP 16:9 mode. The fast output is delivered through 64 LVDS lanes in 260MHz DDR manner. The ADC resolution can be selected in 10b to 14b range. The power consumption is 2W in 12MP/60fps mode.

The pixel full well is 13Ke-. The read noise is 10e in rolling shutter mode and 30e with global shutter, meaning DR of 62dB with rolling shutter or 52dB with the global one. The reported QE for Bayer color version is 40%, 45%, 43% at 470, 540, 620 nm respectively. The monochrome version's QE is 50%, 18%, 11% at 500, 850, 900 nm respectively.

The KAC-12040 Image Sensor is available in monochrome and Bayer color configurations, and is sampling now with production planned for Q2, 2013. An evaluation system that allows detailed analysis of the sensor’s performance is expected to be available in Q4, 2012.

The KAC-12040 CMOS sensor is said to be the first in a planned family of CMOS devices that complement Truesense Imaging’s CCD portfolio by providing the functionality and flexibility available uniquely from CMOS technology.

12:08 PM

Omnivision Announces Improved Version of OmniBSI-2

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PR Newswire: OmniVision announces the OV8835, a 8MP 1.4um pixel sensor for smartphones and tablets, an improved version of similarly speced OV8830. The 1/3.2-inch OV8835 is built on a newly improved 1.4um OmniBSI-2 pixel that delivers dramatically improved sensitivity of 1000 mV/(Lux-sec), a 20% improvement over the previous-generation OV8830 (however, the product brief doc gives 824mV/(Lux-sec), same as the older OV8830). Other performance improvements over the OV8830 include a 20% improvement in low-light performance and a 25% improvement in full-well capacity. (Note that the older OV8830 was said to deliver 20% improvement in peak QE in all color channels, 35% improvement in low-light sensitivity, and 45% increase in full well capacity over the first generation OmniBSI). The dark current of the new sensor is 10e/s at 50C.

The new OV8835 sensor delvers 30fps at full 8MP resolution for zero shutter lag (was 24fps in the older OV8830). The current consumption at that speed is 152mA, the power is 265mW. It is capable of capturing full 1080p30 video with EIS, or 720p60 video with full horizontal FOV. The sensor's 2 x 2 binning functionality with post-binning resampling filter minimizes special artifacts and removes image artifacts around edges.

The OV8835 fits into an industry standard 8.5 x 8.5 mm package. It is currently available for sampling and is expected to enter volume production in the Q4 2012.

11:54 AM

Omnivision Announces Low Cost 5MP BSI Sensor

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PR Newswire: OmniVision introduces the OV5645, a 1.4um BSI pixel-based 5MP SOC that targets the cost-sensitive segment of the mobile handset market. As the successor to a popular OV5640, the new low-cost OV5645 has retained only a MIPI port, eliminating both the bandwidth-limited DVP interface and the costly embedded JPEG compressor. With an embedded AF VCM driver, the OV5645 offers further cost savings for manufacturers.

"Industry analysts predict 5-megapixel image sensors will remain highly popular for mobile devices for the next few years. Consequently, there is an increased need for cost-effective 5-megapixel cameras that meet the requirements of mainstream mobile markets," explained Per Rosdahl, senior product marketing manager at OmniVision. "The OV5645 SOC sensor provides handset manufacturers with a fully-featured yet extremely cost-effective solution that delivers the high-quality image capture and HD video currently required in the mainstream handset market. In addition, the OV5645's increased CRA enables ultra-thin camera modules with z-heights of approximately 4 mm, which is a key requirement for many OEMs' future products."

The OV5645 also features a new picture-in-picture (PIP) based on a master/slave configuration where a secondary camera (e.g., one based on the OV7965) can be connected to a master camera (OV5645).

The new OV5645 offers 720p60 or 1080p30 video modes. The 720p HD video is captured in full FOV with 2 x 2 binning. Additionally, a unique post-binning, re-sampling filter function removes zigzag artifacts around slant edges and minimizes spatial artifacts to deliver even sharper, crisper color images.

The OV5645 comes in CSP and RW packaging options and is now available for sampling, with mass production expected to begin in the Q1 2013.

11:28 AM

New Panasonic and ON Semi Catalogs

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Panasonic and ON Semiconductor published new catalogs presenting their image sensor lineups.

Update: According to Panasonic Annual Report 2012, its businesses are undergoing a reorganization with the main focus in semiconductors shifting to image sensors and power devices "which continue to exhibit high-growth potential" (see page 12, 33):

2:18 PM

Image Processing News: Mobileye, ST, CogniVue

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Marketwire: Mobileye and ST announce that their jointly developed vision processor SoC, using Mobileye's EyeQ technology, is now deployed in more than one million vehicles around the world. With a growing list of manufacturers building the system into their vehicles, including BMW, GM, Volvo, Ford and many more, ST and Mobileye expect to continue to expand their presence in the automotive safety market.

Developing driver safety technology since 2005, Mobileye and ST have delivered two generations of vision processors that use Mobileye's collision avoidance technology and ST's automotive-grade manufacturing and expertise to 'interpret' a scene in real-time and provide drivers and their vehicles with an immediate evaluation. The third-generation EyeQ3 is in development and will be introduced by car makers as early as 2014.

"The deployment of our millionth device is a major milestone in Mobileye's development and growth, and speaks to the strength of our partnership with STMicroelectronics," said Ziv Aviram, CEO of Mobileye. "More significantly, it exemplifies the growing commitment of global automakers, lawmakers and consumers to making driver safety a top priority, a reality we can all be proud of."

Marketwire: CogniVue unveils its next generation APEX-2 Image Cognition Processing engine that is said to revolutionizes embedded vision technology. The APEX-2 makes significant advances in vision processing performance per area per power over the original APEX (which already had up to a 10x advantage over competitive approaches). CogniVue will be releasing new ICP products based on APEX-2 in 2013 and will also be licensing APEX-2 IP to strategic partners.

"Our ICP products, based on our current APEX technology, are already penetrating a number of markets. We see significant semiconductor vendors struggling with a lack of adequate vision processing IP (chips and software) to complement their existing processor architectures similar to when GPUs were first introduced for graphics processing more than a decade ago." said Simon Morris, CEO of CogniVue Corporation. "By licensing APEX technology to strategic partners like Freescale, we enable new embedded vision roadmaps in different markets, accelerate the propagation of our technology into even more applications, and grow our code base overall. With APEX-2, we have an even higher performance embedded vision processing platform with enhanced flexibility to advance our next-gen ICP product line while also enabling our strategic partners like Freescale."

"Today's collision avoidance systems are typically enabled by digital signal processors or field-programmable gate arrays. Freescale is taking a different approach by integrating CogniVue's Image Cognition Processing IP into our processors, providing massively parallel processing in small packages and with very low power consumption." said Ray Cornyn, VP of Freescale's Automotive MCU Division.
1:58 PM

Chipworks on Leica-CMOSIS-ST Full Frame Sensor and More

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Chipworks concludes its full frame sensor reviews by a discussion of the new Leica "M" rangefinder sensor designed by CMOSIS in cooperation with ST and manufactured by ST. The sensor is based on ST's IMG175 300 mm Cu process, originally developed for 1.75um mobile CIS. The process has been adapted to 6um pixels and use 0.11um design rules for the front end of line (FEOL) processing and 90nm design rules for the BEOL. This is the most advanced process node among the full frame sensors vendors.
1:30 PM

TSMC Reports Improvements in Sensor Optics

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Seeking Alpha published TSMC quarterly earnings call transcript. The company's CEO Morris Chang briefly mentions CIS group achievements:

"Another product segment, CMOS image sensor. We have made significant improvements in optical performance. And dual cameras and higher-resolution sensors have been introduced in smartphones and tablets as an example of value-added increase in mobile products."
8:46 AM

Chipworks Reviews Canon DSLR Sensors

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Chipworks continues its DSLR review series. The second part talks about Canon sensors, designed and manufactured by Canon itself. Canon sensor from 1DX full frame camera uses 5T pixel with no sharing. The additional transistor connecting FD in three rows is used for binning:

Canon 1DX pixel

So far Canon used 0.5um process for its full frame DSLR sensors:

10:32 PM

Chipworks Reviews DSLR Sensors: Sony and Nikon

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Chipworks starts a series of full frame DSLR sensor reviews. The first part talks about sensors found inside Nikon cameras from 2004 till today. Chipworks has analyzed the pixel structures of APS-C and full frame sensors used in 10 Nikon DSLRs. Six cameras use Nikon-designed, Renesas fabricated CIS, while four cameras are based on Sony sensors:


A shared pixel structure was used in both Sony latest 36MP 4.75um-pixel IMX094 (made in 0.18um process) and Renesas 7.3um-pixel NC81366W (using 0.25um process):

Sony IMX094 from the D800
Nikon NC81366W from the D4

Thanks to RF for the link!
11:40 AM

NIT to Show 1.3MP GS + 140dB WDR Sensor

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New Imaging Technology (NIT) announces a new global shutter member of its WDR sensor family - the 1.3MP, 140dB NSC1003. It's said to be the first sensor delivering a DR of more than 140dB in a single frame, a resolution of 1.3MP and a global shutter function combined. The sensor is based on 6.8um pixels and has 2/3-inch optical format. The sensor has global and rolling shutter readout modes and provides a differential analog output. The NSC1003 is available for pre-order.

NIT is going to demo the new sensor at the VISION Show 2012 in Stuttgart on Nov. 6-8. NIT also nominated for Vision Award for its MAGIC 3D stereoscopic platform.

NSC1003
9:18 AM

Canon Explains Why it Got Emmy Sensor Award

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Canon announces that it will be recognized at the 64th Annual Technology & Engineering Emmy Awards for "Improvements to Large Format CMOS Imagers for Use in High Definition Broadcast Video Cameras."

Canon debuted its large format CMOS sensor in EOS C300 Digital Cinema Camera in November of 2011 at a global launch event held at Paramount Studios in Hollywood. By exploring alternatives to the established Bayer color filter array algorithms, Canon was able to achieve an overall image quality capture through its CMOS sensor that has helped bring digital cinema closer to the superb aesthetics associated with 35 mm motion picture film.

Over the past 10 months, the company has introduced a total of three high-definition, high-performance Cinema EOS digital cinema cameras—the EOS C300 Digital Cinema Camera, the EOS C500 4K Digital Cinema Camera and the compact, lightweight EOS C100 Digital Video Camera—all built around Canon's Super 35mm CMOS image sensor technology specifically developed for Cinema EOS motion image capture. Separately, the EOS-1D C 4K DSLR Cinema Camera, equipped with an 18.1-megapixel full frame (36 mm x 24 mm) CMOS image sensor, also joined the Cinema EOS product family in April of this year. For professional photographers, and independent and student filmmakers, Canon has also introduced the EOS 5D Mark III digital SLR camera, building on the strong success of the EOS 5D Mark II in film and television production.
10:41 PM

Truesense Imaging Announces 1080p60 CCD with 7.4um Pixels and More

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Truesense Imaging launches 1080p and 4MP CCDs based on 7.4um pixels. The KAI-02170 CCD is a 1” optical format device in 1080p (1920 x 1080) resolution supporting frame rates up to 60 fps ( with 4 outputs), while the KAI-04070 provides 4MP (2048 x 2048) resolution in a 4/3 optical format at up to 28 fps. When compared to a 5.5um pixel, signal-to-noise and low light performance in 7.4um platform have been enhanced through an 80% increase in light gathering capability of the pixel, and smear rejection has been improved four-fold to -115 dB. Dynamic range has been doubled to 70 dB, and can be extended even further to 82 dB in binned pixel operation.

The KAI-02170 and KAI-04070 CCDs are sampling today, with a full evaluation kit available that allows the performance of the new devices to be examined in detail. Truesense blog tells more about the placement of the new devices in the company's product line.
9:37 AM

A simplified overview of the revised Marpol Annex V (resolution MEPC.201(62))

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Simplified overview of the discharge provisions of the revised
MARPOL Annex V (resolution MEPC.201(62)) which will enter into force on
1 January 2013
(for more detailed guidance regarding the respective discharge requirements please refer to the text of
MARPOL Annex V or to the 2012 Guidelines for the Implementation of MARPOL Annex V)


A simplified overview of  the revised Marpol Annex V (resolution MEPC.201(62)) has been issued by the International Maritime Organisation. The annexe become mandatory 1 January 2013.
The annexe on if, where, when and how ships and offshore facilities can dispose of garbage.
Download the PDF Here.

Write to me at marinenotes4u@gmail.com,283928@gmail.com.::MK::.
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Ships electrical plant and distribution system for the A.C. generators

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How alternating current is produced onboard ?

A coil of wire rotating in a magnetic field produces a current. The current can be brought out to two slip rings which are insulated from the shaft. Carbon bushes rest on these rings as they rotate and collect the current for use in an external circuit. Current collected in this way will be alternating, that is, changing in direction and rising and falling in value. To increase the current produced, additional sets of poles may be introduced.


The magnetic field is provided by electromagnets so arranged that adjacent poles have opposite polarity. These 'field coils', as they are called, are connected in series to an external source or the machine output.

Three-phase alternator output

Fig: Three-phase alternator output

If separate coils or conductors are used then several outputs can be obtained. Three outputs are usually arranged with a phase separation of 120°, to produce a three-phase supply. The supply phasing is shown in fig . The three-phase system is more efficient in that for the same mechanical power a greater total electrical output is obtained. Each of the three outputs may be used in single-phase supplies or in conjunction for a three-phase supply. The separate supplies are connected in either star or delta formation . 

The star formation is most commonly used and requires four sliprings on the alternator. The three conductors are joined at a common slipring and also have their individual siipring. The central or neutral line is common to each phase. The delta arrangement has two phases joined at each of the three sliprings on the alternator. A single-phase supply can be taken from any two sliprings.

Star and delta three-phase connections

Fig: Star and delta three-phase connections

So far, alternator construction has considered the armature rotating and the field coils stationary. The same electricity generating effect is produced if the reverse occurs, that is, the field coils rotate and the armature is stationary. This is in fact the arrangement adopted for large, heavy duty alternators.

The field current supply in older machines comes from a low-voltage direct current generator or exciter on the same shaft as the alternator. Modern machines, however, are either statically excited or of the high-speed brushless type. The exciter is required to operate to counter the effects of power factor for a given load. 

The power factor is a measure of the phase difference between voltage and current and is expressed as the cosine of the phase angle. With a purely resistance load the voltage and current are in phase, giving a power factor of one. The power consumed is therefore the product of voltage and current. Inductive or capacitive loads, combined with resistance loads, produce lagging or leading power factors which have a value less than one. The power consumed is the product of current, voltage and power factor.

The alternating current generator supplying a load has a voltage drop resulting from the load. When the load has a lagging power factor this voltage drop is considerable. Therefore the exciter, in maintaining the alternator voltage, must vary with the load current and also the power factor. The speed change of the prime mover must also be taken into account.

Hand control of excitation is difficult so use is made of an automatic voltage regulator (AVR). The AVR consists basically of a circuit fed from the alternator output voltage which detects small changes in voltage and feeds a signal to an amplifier which changes the excitation to correct the voltage. Stabilising features are also incorporated in the circuits to avoid 'hunting' (constant voltage fluctuations) or overcorrecting. Various designs of AVR are in use which can be broadly divided into classes such as carbon pile types, magnetic amplifiers, electronic types, etc,

The statically excited alternator has a static excitation system instead of a d.c. exciter. This type of alternator will more readily accept the sudden loading by direct on-line starting of large squirrel cage motors. The static excitation system uses transformers and rectifiers to provide series and shunt components for the alternator field, that is, it is compounded. Brushes and sliprings are used to transfer the current to the field coils which are mounted on the rotor.

The terminal voltage from the alternator thus gives the no-load voltage arid the load current provides the extra excitation to give a steady voltage under any load condition. The careful matching of components provides a system which functions as a self regulator of voltage. Certain practical electrical problems and the compensation necessary for speed variation require that a voltage regulator is also built into the system.

The brushless high speed alternator was also developed to eliminate d.c. exciters with their associated commutators and brushgear. The alternator and exciter rotors are on a common shaft, which also carries the rectifiers. The exciter output is fed to the rectifiers and then through conductors in the hollow shaft to the alternator field coils. An automatic voltage regulator is used with this type of alternator.

Alternator construction

Fig: Alternator construction

The construction of an alternator can be seen in Figure above. The rotor houses the poles which provide the field current, and these are usually of the salient or projecting-pole type. Slip rings and a fan are also mounted on the rotor shaft, which is driven by the auxiliary engine. The stator core surrounds the rotor and supports the three separate phase windings. Heat is produced in the various windings and must be removed by cooling. The shaft fan drives air over a water-cooled heat exchanger. Electric heaters are used to prevent condensation on the windings when the alternator is not in use.

In addition to auxiliary-engine-driven alternators a ship may have a shaft-driven alternator. In this arrangement a drive is taken from the main engine or the propeller shaft and used to rotate the alternator. The various operating conditions of the engine will inevitably result in variations of the alternator driving speed. A hydraulic pump and gearbox arrangement may be used to provide a constant-speed drive, or the alternator output may be fed to a static frequency converter. In the static frequency converter the a.c. output is first rectified into a variable d.c. voltage and then inverted back into a three-phase a.c. voltage. A feedback system in the oscillator inverter produces a constant-output a.c, voltage and frequency.

A.C. distribution system

Fig: A.C. distribution system


Distribution system

An a.c. distribution system is provided from the main switchboard which is itself supplied by the alternators (Figure above). The voltage at the switchboard is usually 440 volts, but on some large installations it may be as high as 3300 volts. Power is supplied through circuit breakers to larger auxiliaries at the high voltage. Smaller equipment may be supplied via fuses or miniature circuit breakers. Lower voltage supplies used, for instance, for lighting at 220 volts, are supplied by step down transformers in the distribution network.

The distribution system will be three-wire with insulated or earthed neutral. The insulated neutral has largely been favoured, but earthed neutral systems have occasionally been installed. The insulated neutral system can suffer from surges of high voltage as a result of switching or system faults which could damage machinery. Use of the earthed system could result in the loss of an essential service such as the steering gear as a result of an earth fault. An earth fault on the insulated system would not, however, break the supply and would be detected in the earth lamp display. Insulated systems have therefore been given preference since earth faults are a common occurrence on ships and a loss of supply in such situations cannot be accepted.

In the distribution system there will be circuit breakers and fuses, as mentioned previously for d.c. distribution systems. Equipment for a.c. systems is smaller and lighter because of the higher voltage and therefore lower currents. Miniature circuit breakers are used for currents up to about 100 A and act as a fuse and a circuit breaker. The device will open on overload and also in the event of a short circuit. Unlike a fuse, the circuit can be quickly remade by simply closing the switch. A large version of this device is known as the 'moulded-case circuit breaker' and can handle currents in excess of 1000 A. Preferential tripping and earth fault indication will also be a part of the a.c. distribution system. These two items have been mentioned previously for d.c. distribution systems.


Alternating current supply

Three-phase alternators arranged for parallel operation require a considerable amount of instrumentation. This will include ammeters, wattmeter, voltmeter, frequency meter and a synchronising device. Most of these instruments will use transformers to reduce the actual values taken to the instrument. This also enables switching, for instance, between phases or an incoming machine and the bus-bars, so that one instrument can display one of a number of values. The wattmeter measures the power being used in a circuit, which, because of the power factor aspect of alternating current load, will be less than the product of the volts and amps. Reverse power protection is provided to alternators since reverse current protection cannot be used. Alternatively various trips may be provided in the event of prime mover failure to ensure that the alternator does not act as a motor.

The operation of paralleling two alternators requires the voltages to be equal and also in phase. The alternating current output of any machine is always changing, so for two machines to operate together their voltages must be changing at the same rate or frequency and be reaching their maximum (or any other value) together. They are then said to be 'in phase'. Use is nowadays made of a synchroscope when paralleling two a.c. machines. The synchroscope has two windings which are connected one to each side of the paralleling switch. A pointer is free to rotate and is moved by the magnetic effect of the two windings. When the two voltage supplies are in phase the pointer is stationary in the 12 o'clock position. If the pointer is rotating then a frequency difference exists and the dial is marked for clockwise rotation FAST and anti-clockwise rotation SLOW, the reference being to the incoming machine frequency.

To parallel an incoming machine to a running machine therefore it is necessary to ensure firstly that both voltages are equal Voltmeters are provided for this purpose. Secondly the frequencies must be brought into phase. In practice the synchroscope usually moves slowly in the FAST direction and the paralleling switch is closed as the pointer reaches the 11 o'clock position. This results in the incoming machine immediately accepting a small amount of load.
A set of three lamps may also be provided to enable synchronising. The sequence method of lamp connection has a key lamp connected across one phase with the two other lamps cross connected over the other two phases. If the frequencies of the machines are different the lamps will brighten and darken in rotation, depending upon the incoming frequency being FAST or SLOW. The correct moment for synchronising is when the key lamp is dark and the other two are equally bright.
Write to me at marinenotes4u@gmail.com,283928@gmail.com.::MK::.
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Exhaust and inlet valves question

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In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low-alloy steels because  _____________./intake valves are less affected to the corrosive action of exhaust gases
The opening of an exhaust valve on a modern, large, low- speed, main propulsion diesel engine, may be actuated by _____________./hydraulic "push rods"
The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by _____________./compressed air pressure
If the intake, or exhaust valve stem clearance is found to be excessive, in addition to too little movement of the  rocker arms, you should check for _____________./collapsed hydraulic valve lifters
A burned exhaust valve may be detected by a higher than  normal ____________./exhaust temperature from a particular cylinder
Which of the listed conditions will occur if a diesel engine exhaust valve is leaking?/All of the above
In a diesel engine, a leaking exhaust valve can cause  _____________./misfiring
Exhaust valve grooving and corrosion is caused by certain components of residual fuel oil. These components are  sodium, sulfur, and _____________./vanadium
The easiest way to locate a defective diesel engine exhaust valves is by _____________./comparing exhaust pyrometer readings
Increasing the exhaust valve tappet clearance of a diesel engine will result in the exhaust valve opening __________./later and closing earlier
Diesel engine exhaust valve springs are under compression when they are __________./in any position
A diesel engine exhaust valve spring is under compression when _____________./all of the above
The intake and exhaust valves used in a diesel engine are returned to their seats by _____________./spring force
In which of the scavenging methods listed will the exhaust valve be located in the cylinder head?/Uniflow
The purpose of an interference angle in a diesel engine exhaust valve is to ________.  I. work in conjunction with valve rotators to rotate   the valve  II. break up seat deposits/II only
The purpose of an interference angle in a diesel engine exhaust valve is to ________. I. break up seat deposits  II. work in conjunction with valve rotators to rotate   the valve/I only
The exhaust valve opens before bottom dead center in a four stroke engine to___________.  I. allow for blow down  II. reduce pumping losses/both I and II
The purpose of an interference angle in a diesel engine exhaust valve is to ________.  I. seat the valve quickly  II. break up seat deposits/both I and II
The purpose of an interference angle in a diesel engine exhaust valve is to ________.  I. work in conjunction with valve rotators to rotate   the valve  II. seat the valve quickly/II only
In a diesel engine, exhaust valves open before the intake ports are uncovered to ___________.  I. reduce pumping losses  II. reduce back pressure/both I and II
A substance found in residual fuels which tends to cause exhaust valve corrosion and grooving, is ____________./vanadium
During diesel engine warm-up, which type of valve lash  adjuster listed allows for the change in length of the  exhaust valves?/Hydraulic
Which of the listed design features is found in an exhaust valve and NOT in an intake valve?/Hard alloy steel construction
Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to _____________./assist in dissipating heat due to the extreme operating  temperatures
A built-up exhaust valve is one in which _____________./the stem and heads are made of different material
The size of the exhaust valve opening is ____________./most critical in a two-stroke/cycle diesel engine
Exhaust valve openings in a diesel engine cylinder head are made as large as practical to _____________./reduce the pumping loss associated with scavenging
The satisfactory operation of diesel engine exhaust valves usually depends on ______________./correct timing and proper seating
Decreasing the exhaust valve clearance of a diesel engine will cause the exhaust valve to open ______________./earlier and remain open longer
Multiple concentric valve springs are often used with diesel engine valves to ____________./operate the valve gear where a larger force is normally  required, but space limitations restrict the use of a single large spring
If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will _____________./open late and close early
Increasing the valve clearance between a valve stem and  rocker arm, will result in the valve _____________./staying open for a shorter period of time
Which of the listed items should be secured before   performing any maintenance on a solenoid operated air start valve?/Electric power
An important design characteristic of an explosion relief valve for a diesel engine is the ability to _________./close quickly in order to prevent an inrush of air
Which statement regarding the arrangement and location of explosion relief valves used on an internal combustion  engines is true_____________?/Minimizing the danger from emission of flame is a key  consideration
Collapsed hydraulic valve lifters in a diesel engine will result in ____________./excessive valve clearance
At what pressure should a cylinder relief valve of an  internal combustion engine be set to relieve?/The device should be set to relieve at a pressure not more than 40 percent in excess of the maximum firing pressure.
The diesel engine valve subjected to most severe conditions of service is the ____________./cylinder exhaust valve
When the cold tappet clearance is less than that specified by the engine manufacturer, the diesel engine valves will _____________./open earlier than normal
In diesel engines, hydraulic valve lifters are used to  ____________./reduce valve gear pounding
Valve lash, or clearance refers to the _____________./clearance between the top of the valve stem and the rocker arm
What is the purpose of a hydraulic valve lash adjuster?/Allows for constant contact between the valve stem and the rocker arm regardless of whether the engine is cold or warm.
Diesel engine valve springs function to _____________./close the valves
Valve cages are used on some large diesel engines to  _____________./facilitate valve removal for servicing
During warm-up the expansion of valve stems due to engine heat, is allowed for by the _____________./valve lash
In a diesel engine, the spring force required for proper valve operation is determined by _____________./cam contour
According to Coast Guard regulations, isolation valves used in keel cooler installations are permitted to be constructed of ____________./bronze
If a single cylinder relief valve on a diesel engine lifts frequently while the engine is running, the cause may be an _____________./incorrectly adjusted fuel injector
Diesel engine air start valve timing is controlled by  _____________./individual cams and valve gear
If there is a "clicking" sound in the valve compartment of a diesel engine, the cause may be _____________./excessive valve lash
Excessively worn, or polished ends on a diesel engine valve spring, indicate ________________./spring surge
Excessive valve clearance will cause a valve to open  _____________./late and close early
The valve stem expansion associated with engine warm-up is allowed for by the ____________./valve lash adjusters
Diesel engine air start system check valves are opened by _____________./starting air pressure
Excessive valve lash in an auxiliary diesel engine will  cause the valves to open _____________./later and close sooner
If the valve lash on a diesel engine is set improperly,  which of the following statements represents the most  serious problem that can develop?/Too little lash may prevent the valves from seating   properly.
If you increase the clearance between a valve stem and  rocker arm, which of the listed conditions will occur?/Valve will open later.
Reducing the clearance between a valve stem and rocker arm will result in the valve _____________./having a longer duration of opening
If you were inspecting the valve springs on an auxiliary diesel engine, your best indication of impending spring  failure would be _____________./cracks in the surface of the spring
If the relief valve on a diesel engine cylinder lifts, the cause could be due to _____________./liquid in the cylinder
Which of the listed items should be secured before   performing any maintenance on a solenoid operated air start valve?/Electric power and starting air
Bouncing of the valve gear in a diesel engine can be caused by _____________./spring surge
Spring surge in diesel engine valve springs can result in _____________./bouncing of the valve gear
If a clicking sound is being produced from within the valve compartment of a diesel engine, the cause may be __________./all of the above
The force exerted by a valve spring to close the diesel  engine valves, is proportional to _____________./spring compression
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