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nb Tanya Louise – Oil Cooling Improvements

Temperature Gauges
Temperature Gauges

Since the engine & hydrostatic transmission were installed in the boat a few years back, the hydraulic oil cooler has been in the same fresh water circuit as the engine’s water cooling system, however this has been causing some heat issues with the engine & hydraulic system under a heavy load, such as when I’m using the onboard generator to run the welding gear. The hydraulic oil temp would rise to over 80°C during the course of a long day’s cruising – such temperatures will degrade the oil very quickly, and in turn will cause premature wear of the very expensive hydraulic pumps. (Not to mention increasing the requirement for hydraulic oil changes, which are very expensive). The engine oil has been cooled by a standard automotive oil radiator, with air forced over the matrix by two large fans. This is also pretty inefficient, so another cooler will be added to replace the automotive one.
This cooling requirement is caused by the inefficiency of hydraulic systems – a simple variable displacement piston pump driving a bent-axis piston motor has an overall efficiency of roughly 80%. Given our engine’s max power of 76HP (56.7kW), this gives an energy loss of 15.2HP (11.33kW) at maximum power. This extra heat overloaded the skin tank, resulting in a cooling system that didn’t really work all too well once the engine was hot.

To solve this issue, we’ve decided to run a raw water circuit using the canal to remove the waste heat from the hydraulic system & engine oil, putting less of a heat load on the skin tank to bring the temperatures down to something reasonable. The image above show the system at running temperature after I installed the monitoring instruments. The top gauge is measuring engine oil temperature, at the point where it’s being fed to the bearings. The bottom one is measuring hydraulic oil temperature.

The engine oil temperature does have to be higher than any other cooling circuit on board, to boil off any condensate from the cylinders. Overcooling the oil in the sump will eventually cause sludging as the oil tries to absorb the resulting water. I’m aiming for a system temperature in the engine oil circuit of 95°C-120°C when the engine is under load & at operating temperature.

Raw Water Suction
Raw Water Suction

Water from the canal is drawn from a skin fitting installed at the last drydock visit, pulling water through a strainer to remove all the large bits of muck. The large slotted screen on the suction skin fitting keeps larger objects out of the intake.

Raw Water Pump
Raw Water Pump

A flexible impeller pump provides the power to move water through the system, in this case about 25L/Min. This pump is a cheap copy of a Jabsco pump from eBay. So far it’s been pretty reliable.

Temperature Senders
Temperature Senders

The temperature senders are standard automotive parts, and some adaptors were required to graft them into the oil lines of both systems. The senser’s 1/8″ NPT threads are here fitted into 1/2″ BSP hydraulic fittings.

Hydraulic Temperature Sender
Hydraulic Temperature Sender

Here’s the hydraulic oil sender installed in the drain line from the main propulsion pump, this should give me a pretty good idea of the temperature of the components in the system, the sender is earthed through the steel hydraulic oil tank.

Engine Oil Temperature Sender
Engine Oil Temperature Sender

The oil temperature sender is installed in the return line to the engine from the heat exchanger. This is measuring the oil temperature the bearings in the engine are being fed with.

Hydraulic Oil Heat Exchanger
Hydraulic Oil Heat Exchanger

The stack of heat exchangers is located on the starboard side of the engine bay, the large one here is cooling the hydraulic oil, the auxiliary pump is continually circulating the oil from the tank through this, then into the return filter on the top of the tank.

Engine Oil Heat Exchanger
Engine Oil Heat Exchanger

The engine oil is fed through this much smaller heat exchanger mounted on the back of the large hydraulic cooler, the last in the circuit before the water is discharged back overboard through a skin fitting.

Remote Oil Filter
Remote Oil Filter

As we’ve got the diverter block on the side of the engine where the oil filter should be, a remote oil filter is fitted above the fuel tank. The thermostat strapped on operates the main engine bay ventilation fans, switching them on once the engine oil reaches 60°C.

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nb Tanya Louise Heating Upgrades – Saloon Heating

With the installation of the new diesel fired heater we’ve noticed a small problem – since the only heat source in the saloon is the stove, even with the diesel heater fired up the temperature doesn’t really change much, as the heat from the radiators in the both the cabins & the head isn’t spreading far enough.

The solution to this problem is obviously an extra radiator in the saloon, however there isn’t the space to fit even a small domestic-style radiator. eBay turned up some heater matrix units designed for kit cars & the like:

3.8kW Matrix
3.8kW Matrix

These small heater matrix units are nice & compact, so will fit into the back of a storage cupboard next to the saloon. Rated at a max heat output of 3.8kW, just shy of the stove’s rated 4kW output power, this should provide plenty of heating when we’re running the diesel heater rather than the fire.

Water & Power
Water & Power

The blower motor has a resistor network to provide 3 speeds, but this probably won’t be used in this install, water connections are via 15mm copper tails. The current plan is to use a pipe thermostat on the flow from the boiler to switch on the blower when the water temperature reaches about 40°C.

Hot Air Outlets
Hot Air Outlets

The hot air emerges from the matrix via 4 55mm duct sockets. This gives enough outlets to cover both the saloon & the corridor down to the cabins.

Hot Air Vents
Hot Air Vents

Standard 60mm Eberspacher style vents will be used to point the warmth where it’s needed.

More to come soon with the install!

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Amano PIX 3000x Timeclock

Front
Front

This is a late 90’s business timeclock, used for maintaining records of staff working times, by printing the time when used on a sheet of card.

Front Internal
Front Internal

Here is the top cover removed, which is normally locked in place to stop tampering. The unit is programmed with the 3 buttons & the row of DIP switches along the top edge.

Instructions
Instructions

Closeup of the settings panel, with all the various DIP switch options.

CPU & Display
CPU & Display

Cover plate removed from the top, showing the LCD & CPU board, the backup battery normally fits behind this. The CPU is a 4-bit microcontroller from NEC, with built in LCD driver.

PSU & Drivers
PSU & Drivers

Power Supply & prinhead drivers. This board is fitted with several NPN Darlington transistor arrays for driving the dox matrix printhead.

Printhead
Printhead

Printhead assembly itself. The print ribbon fits over the top of the head & over the pins at the bottom. The drive hammers & solenoids are housed in the circular top of the unit.

Printhead Bottom
Printhead Bottom

Bottom of the print head showing the row of impact pins used to create the printout.

2013-02-13 18.00.09Bottom of the solenoid assembly with the ribbon cable for power. There are 9 solenoids, to operate the 9 pins in the head.

Return Spring
Return Spring

Top layer of the printhead assembly, showing the leaf spring used to hold the hammers in the correct positions.

Hammers
Hammers

Hammer assembly. The fingers on the ends of the arms push on the pins to strike through the ribbon onto the card.

Solenoids
Solenoids

The ring of solenoids at the centre of the assembly. These are driven with 3A darlington power arrays on the PSU board.

Gearbox Internals
Gearbox Internals

There is only a single drive motor in the entire unit, that both clamps the card for printing & moves the printhead laterally across the card. Through a rack & pinion this also advances the ribbon with each print.