The paper presents the influence of the use of rapeseed oil and diesel mixture on diesel engine performance and pollutant emissions. The main focus of the study is to identify the possibility of using rapeseed oil mixed with diesel at tractor engines. The fuel mix used consists of 50% diesel with cetane number (CC) 51 and 50% refined rapeseed oil. The experimental results have led to the conclusion that, in the case of tractor engines, NO and NO_x emissions can be substantially reduced compared to the situation when diesel fuel is used. Following the experimental determinations carried out and presented in the paper, both in load and idle operation, by using a fuel mixture consisting of diesel and rapeseed oil, a NO_x and NO_x emission reduction of up to 25% was achieved. Such a reduction in NO and NO_x emissions is important to emphasize precisely because of the fact that at the moment there is still a large number of U650 tractors in agriculture.

The paper presents a study concerning the influence of air conditioning system operation on the increase of gases emissions from cars. The study focuses on urban operating regimes of the automobile, regimes when the engines have low loads or are operating at idling. Are presented graphically the variations of pollution emissions (CO, CO₂, HC) depending of engine speed and the load on air conditioning system. Additionally are presented, injection duration, throttle position, the mechanical power required by the compressor of air conditioning system and the refrigerant pressure variation on the discharge path, according to the stage of charging of the air conditioning system.

Cars with hybrid powertrain substantially reduce the fuel consumption and the environmental pollution, especially at medium and low speeds, because they uses mostly electrical propulsion. The paper presents the mathematical calculation for working regimes of a car with parallel hybrid powertrain system, mathematical model which permits calculation of the propulsion power and torque, as well as the power and mechanical couple at the electrical generator. Dynamics performances for a car with a parallel hybrid powertrain system are presented and compared with the dynamics performances of the same car equipped only with same gasoline internal combustion engine and without hybrid system. From the point of view of performances, hybrid-powered cars can achieve higher accelerations and traction forces than classic cars during autonomy of electric system, due to the propulsion with this system.

The paper presents a study of smoke emissions for car Dacia Solenza 1.9D-SDI (63HP) which was produced by Renault in Romania. A similar engine can also be found on the Kangoo Express and Kangoo Passenger cars respectively. Smoke emissions are analyzed comparatively, between idling regimes and load regimes. Also are presented variations of engine speed, accelerator pedal position, fuel flow injected, automotive speed, which are taken using OBD II connection and Autocom CARS CDP+ Scanner. To simulate the load regimes chassis dynamometer V-Tech Dyno VT-2/B1 was used. A module for measuring the opacity of the exhaust gases was used, which is in the gas analyzer Ultimax 600. In graphics are shown variations of the opacity of exhaust gases between idling regimes and load regimes considered. The different pollutions levels with smoke are analyzed between idling regimes and low loads, respectively high loads. Conclusions about the level of pollution are stated. Also are make recommendations for operating regimes of the car, so as to reduce the level of pollution.