The OHC 16V-diesel engine Y 20 DTH, which is used in the Astra-G and Zafira, has been revised for MY 2003. The purpose of the revision was to reduce the exhaust gas emissions and achieve a quieter engine.
The majority of the significant features of the revision of the Y 20 DTH have been taken from the Y 22 DTR and are:
- New radial piston-distributor injection pump with pre-injection VP 44 PSG 16
- New engine management PSG 16
- Throttle valve
- Electrically controlled exhaust gas recirculation valve cooled by coolant
- Fuel radiator
The above-mentioned changes are illustrated below and described in greater detail.
Radial Piston-Distributor Injection Pump with Pre-Injection Vp 44 Psg 16
The VP 44 PSG 16 is a further development of the existing VP 44 versions and permits injection pressures of up to 1800 bar at the jet. Thanks to pre-injection and the use of even faster high pressure solenoid valves, the optimised injection pump is characterised by its quietness.
One principal characteristic of the VP 44 PSG 16 is a single combined pump and engine control unit, which is permanently connected to the injection pump in hybrid technology.
• Service: During assembly work, in which the wiring harness plug has been unplugged from the engine or pump control unit, the protective caps KM-6154 must be fitted on the wiring harness connections of the control unit, which serves to protect the contacts. The injection pump and control unit cannot be separated and must be replaced together in one module if a fault arises in one of the components.
- 1. Special tool KM-6154 (to cover the wiring harness connection)
- 2. Pump control unit with integrated engine control unit
- 3. Radial piston distributor injection pump VP 44 PSG 16
Throttle Valve
The purpose of the throttle valve is to reduce vibration when turning off the engine.
When turning off the engine, a signal from the engine control causes the throttle valve to be triggered and closed via the solenoid valve of the throttle valve using a vacuum. The fact that the throttle valve closes at the time when the engine is turned off, causes the turning off process to be damped considerably, thus making travel in the car more pleasant.
- 1. Throttle valve connection
- 2. Throttle valve vacuum unit
- 3. Solenoid valve of throttle valve
Electrically Controlled Exhaust Gas Recirculation Valve Cooled by Coolant
The exhaust gas recirculation valve sits in the upper part of the intake manifold, has two coolant connections and one wiring harness plug connection.
The cooling of the exhaust gas recirculation valve supports the effects of recirculating the exhaust gas by a clear reduction in the temperature of the recirculated exhaust gas (reduction of oxides of nitrogen).
Triggering the exhaust gas recirculation valve electrically permits an even more precise adjustment to the operating status of the engine in comparison with pneumatic regulation, which results in a further reduction in the oxides of nitrogen.
- 1. Exhaust gas recirculation valve
- 2. Coolant connection, supply side
- 3. Wiring harness plug
- 4. Coolant connection, return side
Fuel Cooling
The high pressures in the VP 44 PSG 16 cause the fuel to heat up significantly. This leads to expansion of the fuel, causing its density to be lower. To avoid a resulting loss of power, the fuel in the return line is cooled to a temperature of +27 °C.
The thermoswitch valve attached to the fuel tank routes the fuel through the fuel cooler if it is above a temperature of +27 °C. During this process, the fuel in the return line flows through the fuel cooler attached to the floor pan of the vehicle and is cooled by the cooling ribs positioned longitudinally in the slipstream.
- 1. Fuel tank
- 2. Thermoswitch valve
- 3. Bracket for fuel and brake lines
- 4. Fuel radiator
