series characteristics
The various Changfa engine series are all diesel engines. They each have some distinct differences and defining characteristics, but we have focused on the ZS series which are the largest of the horizontal single-cylinder designs. These are a good match with the power requirements of most rural New Zealand homes and lifestyle blocks.
| Value | Units | ZS195 | ZS1100 | ZS1115 | ZS1130 |
|---|---|---|---|---|---|
| Type | description | single cylinder, horizontal, evaporative hopper water cooling, 4-stroke diesel | single cylinder, horizontal, evaporative hopper water cooling, 4-stroke diesel | single cylinder, horizontal, evaporative hopper water cooling, 4-stroke diesel | single cylinder, horizontal, evaporative hopper water cooling, 4-stroke diesel |
| Cylinder displacement | litres | 0.815 | 0.903 | 1.1945 | 1.659 |
| Combustion chamber type | description | swirl combustion | swirl combustion | direct injection | direct injection |
| Bore | mm | 95 | 100 | 115 | 130 |
| Stroke | mm | 95 | 100 | 115 | 120 |
| Rated power/Speed | kW/rpm | 10.6/2200 | 12.1/2200 | 16.2/2200 | 22/2200 |
| Max Torque | N.m | ~51.6 | 58.8 | 78.8 | 78.8 |
| RPM at max torque | rpm | ~1760 | ~1760 | ~1760 | ~1760 |
| Specific fuel consumption at rated condition | g/kW.h | 258.4 | 246.2 | 244.8 | 252.7 |
| Idle speed | rpm | 800 | 800 | 800 | 800 |
| Starting mechanism | . | hand crank or electric motor | hand crank or electric motor | hand crank or electric motor | hand crank or electric motor |
| Net weight | kg | 145 | 155 | 185 | . |
| Overall dimensions LxWxH | mm | 814x480x618 | 821x410x671 | 858x450x699 | 915x435x757 |
| Horsepower (approx.) | hp | 11.5 | 15 | 22 | 30 |
Calculations
Start by calculating how many kilowatts or kVA you need to power your necessary equipment. Then add maybe 20 or 30 percent as contingency. That gives you the alternator capacity you need.
From that you can calculate the prime mover (engine) output you need to drive that. Engines outputs are often specified in horsepower (hp). There are old imperial and newer metric versions of this unit but the different is relatively small (746 vs 735 kilowatts respectively).
So divide your required kW value for your alternator by 0.735 to convert to horsepower.
For example:
- You determine you need about 5 kW to run your electrical stuff.
- Multiply by 1.2 to give 20% contingency = 6kW.
- Then to get horsepower: kW x 0.735 = 8.1 hp.
Remember that with a Power Factor for your load of 0.8, that 6kw of power can also be stated as 7.5 kVA.
So you need a generator system with at least 6kW (same as 7.5kVA) and an 8hp motor.
You should have a fairly closely matched engine and alternator. If your engine is larger than necessary for your alternator, you’ll just burn more fuel than you should, with a loss of efficiency. If your alternator is too large for the engine, the engine will be overloaded and unable to deliver the power you need.