PSA PEUGEOT CITROËN is bringing out a new high-pressure direct-injection petrol engine featuring lean-burn stratified-charge technology. It is the first engine of this type to be developed by a European carmaker. The new engine HPi was developed in-house by PSA PEUGEOT CITROËN over a period of 121 weeks with a total investment budget of FF 420 million (64 million euro). It will be manufactured at the Trémery engines plant in France’s Moselle region at a rate of 200 units per day. The HPi engine will be fitted on upper-mid-range Peugeot and Citroën vehicles from the second quarter of 2000. 

The new HPi engine has a capacity of two litres and develops an output power of 103 kW (143 bhp). Specific advantages include the following:

Fuel consumption is 19% lower than the previous-generation XU two-litre engine and 10% lower than the recent EW two-litre indirect-injection engine (regulatory cycle). On an urban driving cycle, the improvement is even more remarkable, with consumption 21% lower than the XU and 11% lower than the EW. 

Engine response at low running speed is improved, with torque of 170 Nm available at 2000 rpm, an improvement of 9.6% on the XU engine and 3.6% on the EW.  Environmental performance is improved through a significant reduction in CO2 emissions, which is proportional to fuel consumption. Emissions are well within the Euro 3 regulations (2001) and compatible with the Euro 4 standards scheduled for 2005.

To achieve these improvements, PSA PEUGEOT CITROËN designed the HPi engine using the most advanced technology available today: lean-burn stratified-charge direct fuel injection. 

Stratified-charge technology involves concentrating an inflammable air/petrol mixture in the vicinity of the spark plug, then filling the rest of the combustion chamber with air. Intake must be closely matched to engine speed and requires precise fuel injection directly into the combustion chamber.

The Group developed the high-pressure petrol injection pump for the HPi engine through a joint venture with Siemens. The pump supplies injection pressure of between 30 and 100 bars, compared with 3.5 bars on a conventional petrol engine. The high injection pressure and lean fuel mix that can be used with stratified charge, substantially reduce the amount of fuel required for combustion, and so bring significant fuel savings. 

Owing to the excess air in the combustion mix, however, the exhaust gas contains far more oxygen than a conventional engine. Special measures are therefore required to reduce emissions of nitrogen oxides (NOx). To solve this problem, PSA PEUGEOT CITROËN has developed a sequential NOx treatment system based on a storage-release principle. 

The new HPi direct-injection petrol engine marks the latest step in an ambitious engine development policy initiated by PSA PEUGEOT CITROËN in 1998 with the HDi high-pressure common-rail diesel engine.  

(May 25, 2000)