Indirect Injection - Advantages of Indirect Injection Combustion Chambers

Advantages of Indirect Injection Combustion Chambers

• Smaller diesels can be produced.
• The injection pressure required is low, so the injector is cheaper to produce.
• The injection direction is of less importance.
• Indirect injection is much simpler to design and manufacture; less injector development is required and the injection pressures are low (1500 psi versus 5000 psi and higher for direct injection)
• The lower stresses that indirect injection imposes on internal components mean that it is possible to produce petrol and indirect injection diesel versions of the same basic engine. At best such types differ only in the cylinder head and the need to fit a distributor and spark plugs in the petrol version whilst fitting an injection pump and injectors to the diesel. Examples include the BMC A-Series and B-Series engines and the Land Rover 2.25/2.5-litre 4-cylinder types. Such designs allow petrol and diesel versions of the same vehicle to be built with minimal design changes between them.
• Higher engine speeds can be reached, since burning continues in the prechamber. The Mercedes-Benz type prechamber is able to achieve over 6000rpm in a turbocharged engine.
• Indirect injection is superior for running on thicker vegetable oil fuel, due to lower pressure injection, a longer burn time and increased swirl ensuring more complete combustion.