Direct injection
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Modern diesel engines make use of one of the following direct injection methods:
[edit] Distributor pump direct injection
The first incarnations of direct injection diesels used a rotary pump much like indirect injection diesels; however the injectors were mounted in the top of the combustion chamber rather than in a separate pre-combustion chamber. Examples are vehicles such as the Ford Transit and the Austin Rover Maestro and Montego with their Perkins Prima engine. The problem with these vehicles was the harsh noise that they made and particulate (smoke) emissions. This is the reason that in the main this type of engine was limited to commercial vehicles— the notable exceptions being the Maestro, Montego and Fiat Croma passenger cars. Fuel consumption was about fifteen to twenty percent lower than indirect injection diesels, which for some buyers was enough to compensate for the extra noise.
One of the first small-capacity, mass-produced direct-injection engines that could be called refined was developed by the Rover Group.Factdate=February 2007 The 200Tdi 2.5-litre four-cylinder turbodiesel was used by Land Rover in their vehicles from 1989, and the engine used an aluminum cylinder head, Bosch two-stage injection and multi-phase glow plugs to produce a smooth-running and economical engine while still using mechanical fuel injection.
This type of engine was transformed by electronic control of the injection pump, pioneered by Volkswagen Audi group with the Audi 100 Turbo Direct InjectionTDI introduced in 1989. The injection pressure was still only around 300 bar, but the injection timing, fuel quantity, EGR and turbo boost were all electronically controlled. This gave much more precise control of these parameters which made refinement much more acceptable and emissions acceptably low. Fairly quickly the technology trickled down to more mass market vehicles such as the Mark 3 Golf TDI where it proved to be very popular. These cars were both more economical and more powerful than indirect injection competitors of their day.
Modern diesel engines make use of one of the following direct injection methods:
[edit] Distributor pump direct injection
The first incarnations of direct injection diesels used a rotary pump much like indirect injection diesels; however the injectors were mounted in the top of the combustion chamber rather than in a separate pre-combustion chamber. Examples are vehicles such as the Ford Transit and the Austin Rover Maestro and Montego with their Perkins Prima engine. The problem with these vehicles was the harsh noise that they made and particulate (smoke) emissions. This is the reason that in the main this type of engine was limited to commercial vehicles— the notable exceptions being the Maestro, Montego and Fiat Croma passenger cars. Fuel consumption was about fifteen to twenty percent lower than indirect injection diesels, which for some buyers was enough to compensate for the extra noise.
One of the first small-capacity, mass-produced direct-injection engines that could be called refined was developed by the Rover Group.Factdate=February 2007 The 200Tdi 2.5-litre four-cylinder turbodiesel was used by Land Rover in their vehicles from 1989, and the engine used an aluminum cylinder head, Bosch two-stage injection and multi-phase glow plugs to produce a smooth-running and economical engine while still using mechanical fuel injection.
This type of engine was transformed by electronic control of the injection pump, pioneered by Volkswagen Audi group with the Audi 100 Turbo Direct InjectionTDI introduced in 1989. The injection pressure was still only around 300 bar, but the injection timing, fuel quantity, EGR and turbo boost were all electronically controlled. This gave much more precise control of these parameters which made refinement much more acceptable and emissions acceptably low. Fairly quickly the technology trickled down to more mass market vehicles such as the Mark 3 Golf TDI where it proved to be very popular. These cars were both more economical and more powerful than indirect injection competitors of their day.
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